Back to Directory

Gurpal Toor

Professor

Professor, Extension Specialist, & Associate Chair

Professional Summary  |  Research  |  Extension  |  Teaching  |  Service  |  Team Members  |  News  |  Blog

 

Environmental Science & Technology 1426 Animal Science/Agricultural Engineering Building 8127 Regents Drive College Park, Maryland 20742

Expertise

  • Nutrient Management
  • Water Quality
  • Biogeochemistry
  • Soil Chemistry
  • Soil Fertility
  • Extension Specialist
  • Extension

Education

  • Ph.D. Environmental Soil Science, Lincoln University, New Zealand.

PROFESSIONAL SUMMARY

I am a Professor, Extension Specialist, and Associate Chair in the Department of Environmental Science & Technology. My expertise is in Nutrient Management, Soil Fertility, and Water Quality. From 2007 to 2017, I was an Assistant Professor, Associate Professor, and Full Professor in the Department of Soil and Water Sciences at the University of Florida. After receiving my doctoral degree in Environmental Soil Science from Lincoln University, New Zealand, I was trained as a Postdoctoral Researcher in the Plant and Soil Science department at the University of Delaware and as a Research Scientist in the Biological and Agricultural Engineering department at the University of Arkansas.

The overall goal of my research and extension program at the University of Maryland is to conduct basic and applied research and extension to (1) increase understanding of environmental issues as related to agricultural and natural ecosystems and (2) solve environmental problems related to nutrient pollution in the water bodies, including the Chesapeake Bay.

Summary of professional activities, in numbers:

  • 107 peer-reviewed scientific journal articles

  • 37 peer-reviewed extension publications

  • 19 graduate students major advisor

  • 26 invited talks, 55 volunteered talks, and 100+ extension/outreach presentations

  • 121 conference abstracts

  • 22 symposia, conferences organized

  • 21+ competitive grants awarded for over US$ 22.1 million

Consult my professional profiles at the following links for current activities:  Google Scholar  Researchgate  Linkedin  Twitter

RESEARCH

Nitrogen and phosphorus are not only critical nutrients that affect agricultural crop productivity but are pollutants when they reach Chesapeake Bay leading to water quality issues such as eutrophication, onset of algal blooms, and hypoxia. The over-arching goal of research conducted by the group is to develop solutions to manage nutrients in plant root-zone and protect water quality. Our current research efforts are focused on gaining better understanding of processes, mechanisms, and pathways of nitrogen and phosphorus flows in soil-plant-water systems. The outcomes of this research will sustain agricultural production and reduce environmental impacts on water bodies in Maryland and Chesapeake Bay.

The specific objectives of my research program are to:

  • Develop, evaluate, and refine innovative tools using nutrient management principles to reduce nitrogen and phosphorus pollution of water bodies while using waste materials (manures, biosolids) and commercial fertilizers.

  • Investigate mechanisms and processes controlling release and transport of nitrogen and phosphorus from agricultural landscape to drainage ditches, streams, and rivers in the Chesapeake Bay watershed and other water bodies.

Current Projects

A set of integrated research–extension projects are addressing the current issues in the region:

1. Reducing Nitrogen and Phosphorus Losses and Protecting Water Quality in the Chesapeake Bay. The Chesapeake Bay Watershed, located in the northeastern USA, covers an area of ~64,000 square miles, includes six states (MD, NY, PA, DE, VA, WVA) and Washington DC, and is home to >18 million people. The watershed drains to the Chesapeake Bay estuary, located in areas surrounding the state of Maryland. The Bay is the largest estuary in the US and 3rd largest globally, with a land-to-water ratio of 14:1. This means the large area of the watershed drains a large amount of nutrients into the small size of the Bay. The Bay has a long-term history of water pollution and algal blooms stemming from nutrient pollution from agriculture. The row crops, comprising Corn and Soybean rotation, are the most common land use in the watershed. Three primary sources of nutrients (nitrogen and phosphorus) to the Bay are runoff and leaching from agricultural land, developed land, and contributions from urban wastewater. The overall goal of this project is to protect and restore the Chesapeake Bay ecosystem through continued technical support to address water-quality restoration goals and maintain public awareness of Chesapeake Bay restoration. 

       Active Grant:

  • Title: Agriculture and Nonpoint Sources Program Support for the Chesapeake Bay Program Partnership. Funding agency: United States Environmental Protection Agency. Funded amount: $3.2 million. Years: 2021-2027. Role: PI.

2. Managing Nitrogen in Agricultural Production Systems to Optimize Efficiency and Reduce Losses. Innovative and transformative approaches that keep nitrogen in the plant-root zone and minimize offsite losses are needed to meet agricultural production and environmental quality goals. A series of projects are investigating the behavior and transport of nitrogen in crop production systems and connected water bodies.

        Active Grants in Nitrogen:

3. Manipulating Phosphorus in the Soil-Plant-Water Continuum. To optimize and sustain crop production systems in the Chesapeake Bay Watershed, new solutions to reduce legacy soil phosphorus levels, phosphorus leaching, and phosphorus transport to surface waters are needed. A series of projects are addressing the long-standing issues of phosphorus accumulation in soils and losses to water bodies.

       Active Grants in Phosphorus:

  • Title: Field Testing to Revise Phosphorus Management Tool. Funding agency: Maryland Department of Agriculture. Funded amount: $934,750. Years: 2020-2025. Role: PI

  • Title: Environmental Risks and Benefits of Grass Buffer Strips Grown for Nutrient Conservation and Poultry Bedding Production on the Delmarva Peninsula. Funding agency: USDA-NRCS. Funded amount: $165,644. Years: 2020-2022. Role: PI

  • Title: Refining, Retooling, and Implementing the Next Generation of Phosphorus Management Tool to Balance Crop Production and Water Quality Goals in Maryland. Funding Agency: USDA-NIFA. Funded amount: $299,605. Years: 2019-2022. Role: PI

  • Title: Fate of Phosphorus in Biosolids-Amended Soils: Characterizing Short-, Medium-, and Long-term Phosphorus Pools (Phase I). Funding Agency: Metropolitan Washington Council of Governments. Funded amount: $70,000. Years: 2021-2022. Role: PI

4. Assessing the Effectiveness of Soil Health Practices in Enhancing Soil Organic Carbon. The link between soil organic carbon (SOC) and soil health underpins two of humanity's greatest challenges––providing food security and agricultural sustainability to an increasing global population, and mitigating global climate change, for which soil C sequestration on agricultural lands can play a key role. This linkage is increasingly recognized as a crucial aspect of developing and implementing new conservation and regenerative management practices. At the state level in Maryland, the legislation passed a bill in 2017 for the promotion of soil health programs and practices This policy defined a need in Maryland to develop local capacity to measure and track soil C and other soil health metrics for the successful implementation of these programs. The goal of this project is to provide this capacity and strengthen science.

        Active Grants in SOC and Soil Health:

  • Title: Assessing Effectiveness of Soil Health Practices in Enhancing Soil Organic Carbon in Maryland. Funding agency: Harry R. Hughes Center for Agroecology. Funded amount: $400,000. Years: 2019-2021. Role: PI

Research Publications (total published: 107)

Overview of research articles

The published scientific journal articles (total: 107) are organized into the following seven tabs. The first tab includes all publications and the subsequent six tabs are organized based on the topic areas:  Nitrogen, Phosphorus, Carbon, General water quality, Trace metals, and Organic contaminants. Note that 9 articles are listed across topic areas due to the broader scope of these publications.

  • For a complete and updated publication list, consult Google Scholar

  • For obtaining PDF copies of publications, click on the article title to or consult ResearchGate

*Graduate student; ** Postdoctoral researcher/scientist

All peer-reviewed articles (107)

Peer-reviewed articles (total published: 107):

  • For a complete and updated publication list, consult Google Scholar

  • For obtaining PDF copies of publications, click on the article title or consult ResearchGate

*Graduate student; ** Postdoctoral researcher/scientist

107. *Lucas, E., L. Mosesso, T. Roswall, Y-Y. Yang, K. Scheckel, A. Shober, & G.S. Toor. 2022. X-ray absorption near edge structure spectroscopy reveals phosphate minerals at surface and agronomic sampling depths in agricultural Ultisols saturated with legacy phosphorus. Chemosphere, 308, 136288. https://doi.org/10.1016/j.chemosphere.2022.136288

106. *Roswall, T., B.E. Haggard, & G.S. Toor. 2022. Fate and transformations of dissolved phosphorus forms in runoff: Effect of poultry litter and products extracted with variable water extraction ratios. Chemosphere, 308, 136220. https://doi.org/10.1016/j.chemosphere.2022.136220  

105. Spargo, J. T., Lyons, S. E., Clark, J. D., Osmond, D. L., Parvej, R. Md., Pearce, A. W., Slaton, N. A., Saffire, D., Alford, S., Allen, T., Arnall, B., Buob, T., Camberato, J. J., Cardon, G., Culman, S, W., Davenport, J. R., Fernandez, F. G., Florence, R., Flynn, R., Franzen, D., Geisseler, D., Grove, J., Hardy, D., Heckman, J., Hopkins, B., Hoskins, B., Hue, N. V., Huluka, G., Jones, C., Jones, K., Kaiser, D. E., Kalmbach, B., Ketterings, Q. M., Laboski, C. A. M., Lessl, J., Lucas, E., Maguire, R., Mahler, R., Mallerino, A., Margenot, A., McGrath, J. M., Miller, R., Moore, A. D., Morris, T. F., Mylavarapu, R., Nathan, M., Nelson, N. O., Norton, J., Pena-Yewtukhiw, E., Pettinelli, D., Provin, T., Radin, A., Ross, D., Saunders, O., Self, J., Shober, A. L., Sonon, L., Sotomayor, D. R., Stammer, A., Steinke, K., Toor, G.S., Walworth, J., Wang, J. J., Wortmann, C., Zhang, H. (2022). A survey to evaluate the current status of land grant university and state department of agriculture soil fertility recommendations and analytical methods. Ag Data Commons. https://doi.org/10.15482/USDA.ADC/1526506

104. **Yang, Y., M. M. Tfaily, J.L. Wilmoth, & G.S. Toor. 2022. Molecular characterization of dissolved organic nitrogen and phosphorus in agricultural runoff and surface waters. Water Research, 118533. https://doi.org/10.1016/j.watres.2022.118533

103. Angelakis, A.N., M. Valipour, K.-H. Choo, A.T. Ahmed, A. Baba, R. Kumar, G.S. Toor, & Z. Wang. 2021. Desalination: From Ancient to Present and Future. Water, 13, 2222. https://doi.org/10.3390/w13162222

102. Toor, G.S., Y. Yang, S. Das, S. Dorsey, & G. Felton. 2021. Soil health in agricultural ecosystems: current status and future perspectives. Advances in Agronomy, 168, 157–201. https://doi.org/10.1016/bs.agron.2021.02.004

101. *Roswall, T., E. Lucas, Y. Yang, C. Burgis, Isis SPC Scott, & G.S. Toor. 2021. Hotspots of legacy phosphorus in agricultural landscapes: Revisiting water-extractable phosphorus pools in soils. Water, 13, 1006. https://doi.org/10.3390/w13081006

100. **Duan, S., K. Banger, & G.S. Toor. 2021. Evidence of phosphate mining and agriculture influence on concentrations, forms, and ratios of nitrogen and phosphorus in a Florida River. Water, 13, 1064. https://doi.org/10.3390/w13081064

99. *Lucas, E., G.S. Toor, & J. McGrath. 2021. Agronomic and environmental phosphorus decline in coastal plain soils after cessation of manure application. Agriculture, Ecosystems & Environment, 311, 107337. https://doi.org/10.​1016/​j.​agee.​2021.​107337 

98.    Ji, W., J. Xiao, G.S. Toor, & Z. Li. 2021. Nitrate-nitrogen transport in streamwater and groundwater in a loess covered region: Sources, drivers, and spatiotemporal variation. Science of the Total Environment, 761, 143278. https://doi.org/10.1016/j.scitotenv.2020.143278

97.    **Yang, Y., S. Asal, & G.S. Toor. 2021. Residential catchments to coastal waters: Forms, fluxes, and mechanisms of phosphorus transport. Science of the Total Environment, 765,142767. https://doi.org/10.1016/j.scitotenv.2020.142767

96. *Kalev, S., S. Duan, & G.S. Toor. 2021. Enriched dissolved organic carbon export from a residential stormwater pond. Science of the Total Environment, 751, 141773. https://doi.org/10.1016/j.scitotenv.2020.141773

95. Toor, G.S., Y. Yang, M. Morris, P. Schwartz, Y. Darwish, G. Gaylord, & K. Webb. 2020. Phosphorus pools in soils under rotational and continuous grazed pastures. Agrosystems, Geosciences & Environment, 3: e20103. https://doi.org/10.1002/agg2.20103

94. **Yang, Y, A. Goldsmith, I. Herold, S. Lecha, & G.S. Toor. 2020. Assessing soil organic carbon in soils to enhance and track future carbon storage. Agronomy, 10(8), 1139; https://doi.org/10.3390/agronomy10081139

93. *Jani, J., M. Lusk, Y. Yang, & G.S. Toor. 2020. Wet season nitrogen export from a residential stormwater pond. PLoS ONE, 15 (4): e0230908. https://doi.org/10.1371/journal.pone.0230908

92. * Kalev, S. & G.S. Toor. 2020. Concentrations and loads of dissolved and particulate organic carbon in urban stormwater runoff. Water, 12 (4), 1031.https://doi.org/10.3390/w12041031

91. *Jani, J., Y. Yang, M. Lusk, & G.S. Toor. 2020. Composition of nitrogen in urban residential stormwater runoff: variation in concentrations, loads, and source characterization of nitrate and organic nitrogen. PLoS ONE, 15(2): e0229715. https://doi.org/10.1371/journal.pone.0229715

90. *Lusk, M, G.S. Toor, & P. Inglett. 2020. Organic nitrogen in residential stormwater runoff: Implications for stormwater management in urban watersheds. Science of the Total Environment, 707. 135962. https://doi.org/10.1016/j.scitotenv.2019.135962

89. *Rodríguez-Jorquera, I. A., R. C. Colli-Dula, K. Kroll, B.M. Jayasinghe, M.V.P. Marco, C. Silva-Sanchez, G. S. Toor, & N.D. Denslow. 2019. Blood transcriptomics analysis of fish exposed to perfluoro alkyls substances: Assessment of a non-lethal sampling technique for advancing aquatic toxicology research. Environmental Science & Technology, 53: 1441–1452. DOI: 10.1021/acs.est.8b03603

88. **Yang, Y. & G.S. Toor. 2018. Stormwater runoff driven phosphorus transport in an urban residential catchment: Implications for protecting water quality in urban watersheds. Scientific Reports, 8: 11681. DOI:10.1038/s41598-018-29857-x

87. *Jani, J., G.S. Toor. 2018. Composition, sources, and bioavailability of nitrogen in a longitudinal gradient from freshwater to estuarine waters. Water Research, 137: 344–354.

86. *Lusk, M.G., G.S. Toor, & P.W. Inglett. 2018. Characterization of dissolved organic nitrogen in leachate from a newly established and fertilized turfgrass. Water Research, 131: 52­–61.

85. **Dhaliwal, S.S., G.S. Toor, S. Newman, & T.Z. Osborne. 2018. Trace metals in the soils of Water Conservation Area of Florida Everglades: consideration for ecosystem restoration. Journal of Soils and Sediments, 18: 342-351. DOI: 10.1007/s11368-016-1459-5.

84. *Kalev, S.D. & Toor, G.S. 2018. The Composition of Soils and Sediments. In Torok, B. and T. Dransfield, eds., Green Chemistry: An Inclusive Approach. 1st Edition. Elsevier, pp 339–357.

83. *Darre, N.C, G.S. Toor. 2018. Desalination of water: a review. Current Pollution Reports. 4, pages104–111. https://doi.org/10.1007/s40726-018-0085-9 

82. *Rodríguez-Jorquera, I., P. Siroski, W. Espejo, J. Nimptsc, S. Woelfl, P.G. Choueri, R.B. Choueri, C. Moraga, M. Mora, & G.S. Toor. 2017. Latin American Protected Areas: Protected from Chemical Pollution? Integrated Environmental Assessment and Management, 13:360–370. DOI: 10.1002/ieam.1839.

81. *Rodríguez-Jorquera, I, N. Vitale, L. Garner, C. Galbán, N. Duque-Wilckens, N, & G.S. Toor. 2017. Contamination of the Upper Class: Occurrence and Effects of Chemical Pollutants in Terrestrial Top Predators. Current Pollution Reports, 3: 206-219

80. *Lusk, M.G., G.S. Toor, Y. Yang, S. Mechtensimer, M. De, & T. Obreza. 2017. A review of fate and transport of nitrogen, phosphorus, pathogens, and trace organic chemicals in septic systems. Critical Reviews in Environmental Science & Technology. 47: 455–541. http://dx.doi.org/10.1080/10643389.2017.1327787

79. *Lusk, M.G. & G.S. Toor. 2017. Optimizing Hydrologic Properties of Urban Soils. In Lal, R. and B.A. Stewart, eds., Advances in Soil Science: Urban Soils. CRC Press, pp 199–214.

78. **Yang, Y., G.S. Toor, P.C. Wilson, & C.F. Williams. 2017. Micropollutants in groundwater from septic systems: Transformations, transport mechanisms, and human health risk assessment. Water Research. 123: 258–267. DOI: 10.1016/j.watres.2017.06.054

77. Toor, G.S., M.L. Occhipinti, Y. Yang, T. Majcherek, D. Haver, & L. Oki. 2017. Managing urban runoff in residential neighborhoods: nitrogen and phosphorus in lawn irrigation driven runoff. PLoS ONE12 (6), e0179151. DOI: 10.1371/journal.pone.0179151

76. *De, M. & G.S. Toor. 2017. Nitrogen transformations in the mounded drainfields of drip dispersal and gravel trench septic systems. Ecological Engineering, 102: 352–360. DOI: 10.1016/j.ecoleng.2017.02.039

75. **Yang, Y. & G.S. Toor. 2017. Sources and mechanisms of nitrate and orthophosphate transport in urban stormwater from residential catchments. Water Research, 112:176–184. DOI: 10.1016/j.watres.2017.01.039.

74. *Mechtensimer, S. & G.S. Toor. 2017. Septic systems contribution to phosphorus in shallow groundwater: Field-scale studies using conventional drainfield designs. PLoS ONE, 12 (1): e0170304. DOI: 10.1371/journal.pone.0170304

73. *Colon, B. & G.S. Toor. 2016. A review of uptake and translocation of pharmaceuticals and personal care products by food crops irrigated with treated wastewater. Advances in Agronomy, 140:75–100. DOI: 10.1016/bs.agron.2016.07.001.

72. **Yang, Y., G.S. Toor, P.C. Wilson, & C.F. Williams. 2016. Septic systems as hot-spots of pollutants in the environment: Fate and mass balance of micropollutants in septic drainfields. Science of the Total Environment, 566–567:1535–1544. DOI: 10.1016/j.scitotenv.2016.06.043

71. *Mechtensimer, S. & G.S. Toor. 2016. Fate, mass balance, and transport of phosphorus in the septic system drainfields. Chemosphere, 159:153­­–158. DOI:10.1016/j.chemosphere.2016.05.084.

70. *Lusk, M.G. & G.S. Toor. 2016. Biodegradability and molecular composition of dissolved organic nitrogen in urban stormwater runoff and outflow water from a stormwater retention pond. Environmental Science & Technology, 50:3391–3398DOI: 10.1021/acs.est.5b05714. 

69. *Lusk, M.G. & G.S. Toor. 2016. Dissolved organic nitrogen in urban streams: biodegradability and molecular composition studies. Water Research, 96:225–235. DOI: 10.1016/j.watres.2016.03.060.

68. *Rodriguez-Jorquera, I., C. Silva-Sanchez, M. Strynar, N.D. Denslow, & G.S. Toor. 2016. Footprints of urban micro-pollution in protected areas: investigating the longitudinal distribution of perfluoroalkyl substances in wildlife preserves. PLoS ONE, 11(2): e0148654. DOI: 10.1371/journal.pone.0148654.

67. **Yang, Y. & G.S. Toor. 2016. δ15N and δ18O reveal the sources of nitrate-nitrogen in urban residential stormwater runoff. Environmental Science & Technology, 50: 2881–2889. DOI: 10.1021/acs.est.5b05353. 

66. *De, M. & G.S. Toor. 2016. Mass balance of water and nitrogen in the mounded drainfield of a drip-dispersal septic system. Journal of Environmental Quality, 45:1392–1399. DOI: 10.2134/jeq2016.02.0043.

65. Toor, G.S. & J.T. Sims. 2016. Phosphorus leaching in soils amended with animal manures generated with modified diets. Journal of Environmental Quality, 45:1–7. DOI: 10.2134/jeq2015.10.0542.

64. *De, M. & G.S. Toor. 2016. High removal of effluent-borne nitrogen with multiple external electron donors in the engineered drainfield of an advanced septic system. Journal of Environmental Quality, 45:1874–1882. DOI: 10.2134/jeq2016.06.0215.

63. Toor, G.S., & J.T. Sims. 2015. Managing phosphorus leaching in mid-Atlantic soils: importance of legacy sources. Vadose Zone Journal. 14: DOI:10.2136/vzj2015.08.0108.

62. **Zhan, F., He, Y., Li, T., Yang, Y.Y., Toor, G.S. & Zhao, Z. 2015. Subcellular distribution and chemical forms of cadmium in a dark septate endophyte (DSE), Exophiala pisciphila. Environmental Science and Pollution Research. 22:17897-17905.

61. *Rodriguez-Jorquera, I., Kroll,K.J., Toor, G.S.  & Denslow, N.D. 2015. Transcriptional and physiological response of fathead minnows (Pimephales promelas) exposed to urban waters entering into wildlife protected areas. Environmental Pollution. 199: 155-165. DOI: 10.1016/j.envpol.2015.01.021.

60. *De, M. & G.S. Toor. 2015. Fate of effluent-borne nitrogen in the mounded drainfield of an onsite wastewater treatment system. Vadose Zone Journal. DOI: 10.2136/vzj2015.07.0096.

59. **Yang, Y., Toor, G.S. & Williams, C.F. 2015. Pharmaceuticals and organochlorine pesticides in sediments of an urban river in Florida, USA. Journal of Soils and Sediments DOI: 10.1007/s11368-015-1077-7

58. **Yang, Y. & Toor, G.S. 2015. Fate of nutrients, trace metals, bacteria, and pesticides in nursery recycled water. Journal of Water Resource and Protection.7:293-299. DOI:10.4236/jwarp.2015.74023.

57. **Zhan, F., He, Y., Li, T., Yang, Y.Y., Toor, G.S. & Zhao, Z. 2015. Tolerance and antioxidant response of a dark septate endophyte (DSE), Exophiala pisciphila, to cadmium stress. Bulletin of Environmental Contamination and Toxicology. 94: 96-102. DOI. 10.1007/s00128-014-1401-8.

56. **Filipovic, V., Toor, G.S., Ondrasek, G. & Kodesova, R. 2015. Modeling water flow and nitrate-nitrogen transport on future golf courses under turfgrass. Journal of Soils and Sediments. 15: 1847-1859. DOI 10.1007/s11368-014-0980-7.

55. **Wang, H.Y., H. Wang, L. Li Tang, Y. H. Dong, L. Zhao, & G.S. Toor. 2014. Sorption characteristics of cyromazine and its metabolite melamine in typical agricultural soils of China. Environmental Science and Pollution Research. 21: 979-985.

54. Toor, G.S., L. Han, & C.D. Stanley. 2013. Temporal variability in water quality parameters-a case study of drinking water reservoir in Florida, USA. Environmental Monitoring and Assessment. 185: 4305-4320.

53. **Wang, H., Y. Dong, Y. Yang, G.S. Toor, & X. Zhang. 2013. Changes in heavy metal contents in animal feeds and manures in an intensive animal production region of China. Journal of Environmental Sciences. 25: 2435-2442.

52. **Carey, R.O., G. Hochmuth, C.J. Martinez, T.H. Boyer, M.D. Dukes, G.S. Toor, & J.L. Cisar. 2013. Evaluating nutrient impacts in urban watersheds: Challenges and research opportunities. Environmental Pollution. 173:138-149.

51. **Carey, R.O., G. Hochmuth, C.J. Martinez, T.H. Boyer, V.D. Nair, M.D. Dukes, G.S. Toor, A.L. Shober, J.L. Cisar, L.E. Trenholm, & J.B. Sartain. 2012. Regulatory and resource management practices for urban watersheds: The Florida experienceHORTTECHNOLOGY. 22: 418-429.

50. *Khare, Y.P., C.J. Martinez, & G.S. Toor. 2012. Water quality and land use changes in the Alafia and Hillsborough river watersheds, Florida, USA. Journal of American Water Resources Association. 48:1276-1293.

49. *Pannu, M.W., G.S. Toor, G.A. O’Connor, & P.C. Wilson. 2012. Toxicity and bioaccumulation of biosolids-borne triclosan in food crops. Environmental Toxicology & Chemistry. 31: 2130-2137.

48. *Pannu, M.W., G.A. O'Connor, & G.S. Toor. 2012. Toxicity and bioaccumulation of biosolids-borne triclosan in terrestrial organismsEnvironmental Toxicology & Chemistry.  31:646-653.

47. *Chahal, M.K., G.S. Toor, & B.M. Santos. 2012. Chemical characterization of tomato industry wastewater, Florida, United States. Journal of Water Resource and Protection. 4:107-114.

46. *Hagan, D. C. Dobbs, N. Timilsina, F. Escobedo, G.S.Toor, & M. Andreu. 2012. Anthropogenic effects on the physical and chemical properties of subtropical coastal urban soils. Soil Use and Management. 28:78-88.

45. **Carey, R.O., G. Hochmuth, C.J. Martinez, T.H. Boyer, V.D. Nair, M.D. Dukes, G.S. Toor, A.L. Shober, J.L. Cisar, L.E. Trenholm, & J.B. Sartain. 2012.  A Review of Turfgrass Fertilizer Management Practices: Implications for Urban Water QualityHORTTECHNOLOGY. 22: 280-291.

44. *Waria, M., G.A. O’Connor, & G.S. Toor. 2011. Biodegradation of triclosan in biosolids-amended soils. Environmental Toxicology and Chemistry. 30:2488-2496.

43. *Chahal, M.K., G.S. Toor, P. Nkedi-Kizza, & B.M. Santos. 2011. Effect of tomato packinghouse wastewater on phosphorus and cation leaching in a spodosol. Journal of Environmental Quality. 40:999–1009.

42. Abd-Elrahman, A., M. Croxton, R. Pande-Chettri, G.S. Toor, S. Smith, & J. Hill. 2011. In-situ estimation of water quality parameters in freshwater aquaculture ponds using hyperspectral imaging system. ISPRS Journal of Photogrammetry and Remote Sensing. 60:463–472.

41. *Chahal, M.K. & G.S. Toor. 2011. Trace metal leaching in a spodosol irrigated with tomato packinghouse wastewater. Soil Use and Management. 27:480-490.

40. *Chahal, M.K., G.S. Toor, & P. Brown. 2010. Trace metals and polycyclic aromatic hydrocarbons in an urbanized area of Florida. Soil and Sediment Contamination. 19:419–435.

39. *Banger, K., G.S. Toor, T. Chirenje, & L. Ma, 2010. Polycyclic aromatic hydrocarbons in urban soils of different land uses in Miami, Florida. Soil and Sediment Contamination. 19: 231–243.

38. *Banger, K., G.S. Toor, A. Biswas, S.S. Sidhu, & K. Sudhir. 2010. Soil organic carbon fractions after 16-years of applications of fertilizers and organic manure in a Typic Rhodalfs in semi-arid tropics. Nutrient Cycling in Agroecosystems. 86: 391–399.

37. He, Z., H. Zhang, G.S. Toor, Z. Dou, C.W. Honeycutt, & B.E. Haggard. 2010. Phosphorus distribution in sequentially extracted fractions of biosolids, poultry litter, and granulated products. Soil Science. 175: 154–161.

36. Stanley, C.D. & G.S. Toor. 2010. Florida commercial horticultural production:  constraints limiting water and nutrient use efficiency. HortTechnology. 20: 89–93.

35. Toor, G.S. 2009. Enhancing phosphorus availability in low-phosphorus soils by using poultry manure and commercial fertilizer. Soil Science. 174:358–364.

34. Toor, G.S. & B.E. Haggard. 2009.  Phosphorus and trace metal dynamics in soils amended with poultry litter and granulates. Soil Use & Management.  25:409–418.

33.*Banger, K., S.S. Kukal, G.S. Toor, & K. Sudhir, & T. Hanumanthraju. 2009. Impact of long-term additions of chemical fertilizers and farm yard manure on carbon and nitrogen sequestration under rice-cowpea cropping system in semi-arid tropics. Plant and Soil. 318: 27–35.

32. Toor, G.S., R.D. Harmel, B.E. Haggard, & G. Schmidt. 2008. Evaluation of regression methodology with low-frequency water quality sampling to estimate constituent loads for ephemeral watersheds in Texas. Journal of Environmental Quality. 37:1847–1854.

31. Toor, G.S., B.E. Haggard, & A.M. Donoghue. 2007. Water extractable trace elements in poultry litters and granulated products. Journal of Applied Poultry Research. 16:351–360.

30. Toor, G.S., B.E. Haggard, M.S. Reiter, T.C. Daniel, & A.M. Donoghue. 2007. Phosphorus solubility in poultry litters and granulates: influence of litter treatments and extraction ratios. Transactions of the American Society of Agricultural and Biological Engineers. 50:533–542.

29. He, Z., B.J. Cade-Menun, G.S. Toor, A. Fortuna, C.W. Honeycutt, & J.T. Sims. 2007. Comparison of phosphorus forms in wet and dried animal manures by solution phosphorus-31 nuclear magnetic resonance spectroscopy and enzymatic hydrolysis. Journal of Environmental Quality. 36:1086–1095.

28. Kleinman, P.J., D. Sullivan, A. Wolf, R.C. Brandt, Z. Dou, H.A. Elliott, J. Kovar, A.B. Leytem, R.O. Maguire, P. Moore, L. Saporito, A.N. Sharpley, A.L. Shober, J.T. Sims, J.P. Toth, G.S. Toor, H. Zhang, & T. Zhang. 2007. Selection of a water extractable phosphorus test for manure and biosolids as an indicator of runoff loss potential. Journal of Environmental Quality. 36:1357–1367.

27. Toor, G.S., B.E. Haggard, S.M. Williamson, & A.M. Donoghue. 2007. Less environmental effects from granulated litter. World Poultry. 23:26–27.

26. Toor, G.S., S. Hunger, J.D. Peak, J.T. Sims, & D.L. Sparks. 2006. Advances in the characterization of phosphorus in organic wastes: environmental and agronomic applications. Advances in Agronomy. 89:1–72.

25. He, Z., G.S. Toor, C.W. Honeycutt, & J.T. Sims. 2006. An enzymatic hydrolysis approach for characterizing labile phosphorus forms in dairy manure under mild assay conditions. Bioresource Technology. 97:1660–1668.

24. Toor, G.S., B.J. Cade-Menun, & J.T. Sims. 2005. Establishing a linkage between phosphorus forms in dairy diets, feces, and manures. Journal of Environmental Quality. 34:1380–1391.

23. Toor, G.S., J.D. Peak, & J.T. Sims. 2005. Phosphorus speciation in broiler litter and turkey manure produced from modified diets. Journal of Environmental Quality. 34:687–697.

22. Toor, G.S., L.M. Condron, B.J. Cade-Menun, H.J. Di, & K.C. Cameron. 2005. Preferential phosphorus leaching from an irrigated grassland soil. European Journal of Soil Science. 56:155–167.

21. Toor, G.S., J.T. Sims, and Z. Dou. 2005. Reducing phosphorus in dairy diets improves farm nutrient balances and decreases the risk of nonpoint pollution of surface and ground waters. Agriculture Ecosystems & Environment. 105:401–411.

20. Verma, V.K., L.B. Patel, G.S. Toor, P.K. Sharma, & V. Singh. 2005. Dynamics and spatial distribution of soluble salts in ground waters with special reference to their suitability for irrigation in Faridkot District of Punjab, India.  Ecology, Environment and Conservation. 11:119–122.

19. Verma, V.K., L.B. Patel, G.S. Toor, & P.K. Sharma. 2005. Spatial distribution of macronutrients in soils of arid tract of Punjab, India. International Journal of Agriculture and Biology. 7:285–297.

18. Toor, G.S., L.M. Condron, H.J. Di, K.C. Cameron, & J.T. Sims. 2004. Impact of farm dairy effluent application on amounts and forms of phosphorus loss from irrigated grassland. New Zealand Journal of Agricultural Research. 47:479–490.

17. Toor, G.S., L.M. Condron, H.J. Di, & K.C. Cameron. 2004. Seasonal fluctuations in phosphorus loss by leaching from a free draining grassland soil. Soil Science Society of America Journal. 68:1429–1436.

16. Toor, G.S., L.M. Condron, H.J. Di, K.C. Cameron, & J.T. Sims. 2004. Assessment of phosphorus leaching losses from a free draining grassland soil. Nutrient Cycling in Agroecosystems. 69:169–184. 

15. Verma, V.K., P.K. Sharma, V. Singh, L.B. Patel, & G.S. Toor. 2004. Hydrochemical facies of ground waters of Southwestern Punjab, India in relation to their suitability for irrigation. Asian Journal of Microbiology, Biotechnology and Environmental Sciences. 6:379–381.

14. Thind, H.S., C.L. Arora, & G.S. Toor. 2004. Nutrients return through leaf litter and their relations with poplar growth under different treatments of N, irrigation and inter-cropping. Indian Journal of Agroforestry. 62: 41–45.

13. Toor, G.S., L.M. Condron, H.J. Di, K.C. Cameron, & B.J. Cade-Menun. 2003. Characterization of organic phosphorus in leachate from a grassland soil. Soil Biology & Biochemistry. 35:1317–1323.

12. Verma, V.K., L.B. Patel, P.K. Sharma, G.S. Toor, & V. Singh. 2003. Evaluation, characterization and management of soil - water related constraints for sustainable agriculture: an integrated approach using remote sensing and GIS. International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences. 34:280–283.

11. Sinaj, S., C. Stamm, G.S. Toor, L.M. Condron, T. Hendry, H.J. Di, K.C. Cameron, & E. Frossard. 2002. Phosphorus exchangeability and leaching losses from two grassland soils. Journal of Environmental Quality. 31:319–330.

10. Bahl, G.S. & G.S. Toor. 2002. Influence of poultry manure on phosphorus availability and the standard phosphate requirement of crop estimated from quantity–intensity relationships in different soils. Bioresource Technology. 85:317–322.

9. Patel, L.B., V.K. Verma, G.S. Toor, & P.K. Sharma. 2001. Ground water quality for irrigation: Its assessment and management in District Mansa, Punjab (India). Ecology, Environment and Conservation. 7:315–318.

8. Patel, L.B., V.K. Verma, G.S. Toor, & P.K. Sharma. 2000. Beneficial plant nutrient supply from ground waters of arid tract of Punjab.  Ecology, Environment and Conservation. 6:105–108.

7. Patel, L.B., V.K. Verma, G.S. Toor, & P.K. Sharma. 2000. Hydrochemistry of ground waters of southern Punjab, India in relation to their suitability for irrigation.  Ecology, Environment and Conservation. 6:179–183.

6. Verma, V.K., L.B. Patel, P.K. Sharma, G.S. Toor, & C. Singh. 2000. Integrated approach for evaluation, characterisation and management of soil and water related constraints in arid environment of Punjab, India. Asian Journal of Microbiology, Biotechnology and Environmental Sciences. 2:43–50.

5. Bahl, G.S. & G.S. Toor. 1999. Efficiency of P utilization by sunflower grown on residual P fertility. Bioresource Technology. 67:97–100.

4. Toor, G.S. & G.S. Bahl. 1999. Kinetics of phosphate desorption from different soils as influenced by application of poultry manure and fertilizer phosphorus and its uptake by soybean. Bioresource Technology. 69:117–121.

3. Toor, G.S. & G.S. Bahl. 1997.  Effect of poultry manure addition and phosphorus fertilization on phosphorus adsorption and desorption pattern of soils. Ecological Agriculture: Towards Sustainable Development, Center for Research in Rural and Industrial Development, Chandigarh, India, pp.72-98.

2. Toor, G.S., G.S. Bahl, & A.C. Vig. 1997. Pattern of P availability in different soils as assessed by different adsorption equations. Journal of Indian Society of Soil Science. 45:719–723.

1. Toor, G.S. & G.S. Bahl. 1997. Effect of solitary and integrated use of poultry manure and fertilizer phosphorus on the dynamics of P availability in different soils. Bioresource Technology. 62:25–28.

Phosphorus (45)

For obtaining a PDF copy of the publication, click on the article title:

45. *Lucas, E., L. Mosesso, T. Roswall, Y-Y. Yang, K. Scheckel, A. Shober, & G.S. Toor. 2022. X-ray absorption near edge structure spectroscopy reveals phosphate minerals at surface and agronomic sampling depths in agricultural Ultisols saturated with legacy phosphorus. Chemosphere, 308, 136288. https://doi.org/10.1016/j.chemosphere.2022.136288

44. *Roswall, T., B.E. Haggard, & G.S. Toor. 2022. Fate and transformations of dissolved phosphorus forms in runoff: Effect of poultry litter and products extracted with variable water extraction ratios. Chemosphere, 308, 136220. https://doi.org/10.1016/j.chemosphere.2022.136220  

43. **Yang, Y., M. M. Tfaily, J.L. Wilmoth, & G.S. Toor. 2022. Molecular characterization of dissolved organic nitrogen and phosphorus in agricultural runoff and surface waters. Water Research, 118533. https://doi.org/10.1016/j.watres.2022.118533

42. *Roswall, T., E. Lucas, Y. Yang, C. Burgis, Isis SPC Scott, & G.S. Toor. 2021. Hotspots of legacy phosphorus in agricultural landscapes: Revisiting water-extractable phosphorus pools in soils. Water, 13, 1006. https://doi.org/10.3390/w13081006

41. **Duan, S., K. Banger, & G.S. Toor. 2021. Evidence of phosphate mining and agriculture influence on concentrations, forms, and ratios of nitrogen and phosphorus in a Florida River. Water, 13, 1064. https://doi.org/10.3390/w13081064

40. *Lucas, E., G.S. Toor, & J. McGrath. 2021. Agronomic and environmental phosphorus decline in coastal plain soils after cessation of manure application. Agriculture, Ecosystems & Environment, 311, 107337. https://doi.org/10.​1016/​j.​agee.​2021.​107337 

39. **Yang, Y., S. Asal, & G.S. Toor. 2021. Residential catchments to coastal waters: Forms, fluxes, and mechanisms of phosphorus transport. Science of the Total Environment, 765,142767. https://doi.org/10.1016/j.scitotenv.2020.142767

38. Toor, G.S., Y. Yang, M. Morris, P. Schwartz, Y. Darwish, G. Gaylord, & K. Webb. 2020. Phosphorus pools in soils under rotational and continuous grazed pastures. Agrosystems, Geosciences & Environment, 3: e20103. https://doi.org/10.1002/agg2.20103

37. **Yang, Y. & G.S. Toor. 2018. Stormwater runoff driven phosphorus transport in an urban residential catchment: Implications for protecting water quality in urban watersheds. Scientific Reports, 8: 11681. DOI:10.1038/s41598-018-29857-x

36. *Lusk, M.G., G.S. Toor, Y. Yang, S. Mechtensimer, M. De, & T. Obreza. 2017. A review of fate and transport of nitrogen, phosphorus, pathogens, and trace organic chemicals in septic systems. Critical Reviews in Environmental Science & Technology. 47: 455–541. http://dx.doi.org/10.1080/10643389.2017.1327787

35. Toor, G.S., M.L. Occhipinti, Y. Yang, T. Majcherek, D. Haver, & L. Oki. 2017. Managing urban runoff in residential neighborhoods: nitrogen and phosphorus in lawn irrigation driven runoff. PLoS ONE12 (6), e0179151. DOI: 10.1371/journal.pone.0179151

34. **Yang, Y. & G.S. Toor. 2017. Sources and mechanisms of nitrate and orthophosphate transport in urban stormwater from residential catchments. Water Research, 112:176–184. DOI: 10.1016/j.watres.2017.01.039.

33. *Mechtensimer, S. & G.S. Toor. 2017. Septic systems contribution to phosphorus in shallow groundwater: Field-scale studies using conventional drainfield designs. PLoS ONE, 12 (1): e0170304. DOI: 10.1371/journal.pone.0170304

32. *Mechtensimer, S. & G.S. Toor. 2016. Fate, mass balance, and transport of phosphorus in the septic system drainfields. Chemosphere, 159:153­­–158. DOI:10.1016/j.chemosphere.2016.05.084.

31. Toor, G.S. & J.T. Sims. 2016. Phosphorus leaching in soils amended with animal manures generated with modified diets. Journal of Environmental Quality, 45:1–7. DOI: 10.2134/jeq2015.10.0542.

30. Toor, G.S., & J.T. Sims. 2015. Managing phosphorus leaching in mid-Atlantic soils: importance of legacy sources. Vadose Zone Journal. 14: DOI:10.2136/vzj2015.08.0108.

29. Toor, G.S., L. Han, & C.D. Stanley. 2013. Temporal variability in water quality parameters-a case study of drinking water reservoir in Florida, USA. Environmental Monitoring and Assessment. 185: 4305-4320.

28. **Carey, R.O., G. Hochmuth, C.J. Martinez, T.H. Boyer, M.D. Dukes, G.S. Toor, & J.L. Cisar. 2013. Evaluating nutrient impacts in urban watersheds: Challenges and research opportunities. Environmental Pollution. 173:138-149.

27. **Carey, R.O., G. Hochmuth, C.J. Martinez, T.H. Boyer, V.D. Nair, M.D. Dukes, G.S. Toor, A.L. Shober, J.L. Cisar, L.E. Trenholm, & J.B. Sartain. 2012. Regulatory and resource management practices for urban watersheds: The Florida experienceHORTTECHNOLOGY. 22: 418-429.

26. *Khare, Y.P., C.J. Martinez, & G.S. Toor. 2012. Water quality and land use changes in the Alafia and Hillsborough river watersheds, Florida, USA. Journal of American Water Resources Association. 48:1276-1293.

25. *Chahal, M.K., G.S. Toor, P. Nkedi-Kizza, & B.M. Santos. 2011. Effect of tomato packinghouse wastewater on phosphorus and cation leaching in a spodosol. Journal of Environmental Quality. 40:999–1009.

24. He, Z., H. Zhang, G.S. Toor, Z. Dou, C.W. Honeycutt, & B.E. Haggard. 2010. Phosphorus distribution in sequentially extracted fractions of biosolids, poultry litter, and granulated products. Soil Science. 175: 154–161.

23. Toor, G.S. 2009. Enhancing phosphorus availability in low-phosphorus soils by using poultry manure and commercial fertilizer. Soil Science. 174:358–364.

22. Toor, G.S. & B.E. Haggard. 2009.  Phosphorus and trace metal dynamics in soils amended with poultry litter and granulates. Soil Use & Management.  25:409–418.

21. Toor, G.S., B.E. Haggard, M.S. Reiter, T.C. Daniel, & A.M. Donoghue. 2007. Phosphorus solubility in poultry litters and granulates: influence of litter treatments and extraction ratios. Transactions of the American Society of Agricultural and Biological Engineers. 50:533–542.

20. He, Z., B.J. Cade-Menun, G.S. Toor, A. Fortuna, C.W. Honeycutt, & J.T. Sims. 2007. Comparison of phosphorus forms in wet and dried animal manures by solution phosphorus-31 nuclear magnetic resonance spectroscopy and enzymatic hydrolysis. Journal of Environmental Quality. 36:1086–1095.

19. Kleinman, P.J., D. Sullivan, A. Wolf, R.C. Brandt, Z. Dou, H.A. Elliott, J. Kovar, A.B. Leytem, R.O. Maguire, P. Moore, L. Saporito, A.N. Sharpley, A.L. Shober, J.T. Sims, J.P. Toth, G.S. Toor, H. Zhang, & T. Zhang. 2007. Selection of a water extractable phosphorus test for manure and biosolids as an indicator of runoff loss potential. Journal of Environmental Quality. 36:1357–1367.

18. Toor, G.S., B.E. Haggard, S.M. Williamson, & A.M. Donoghue. 2007. Less environmental effects from granulated litter. World Poultry. 23:26–27.

17. Toor, G.S., S. Hunger, J.D. Peak, J.T. Sims, & D.L. Sparks. 2006. Advances in the characterization of phosphorus in organic wastes: environmental and agronomic applications. Advances in Agronomy. 89:1–72.

16. He, Z., G.S. Toor, C.W. Honeycutt, & J.T. Sims. 2006. An enzymatic hydrolysis approach for characterizing labile phosphorus forms in dairy manure under mild assay conditions. Bioresource Technology. 97:1660–1668.

15. Toor, G.S., B.J. Cade-Menun, & J.T. Sims. 2005. Establishing a linkage between phosphorus forms in dairy diets, feces, and manures. Journal of Environmental Quality. 34:1380–1391.

14. Toor, G.S., J.D. Peak, & J.T. Sims. 2005. Phosphorus speciation in broiler litter and turkey manure produced from modified diets. Journal of Environmental Quality. 34:687–697.

13. Toor, G.S., L.M. Condron, B.J. Cade-Menun, H.J. Di, & K.C. Cameron. 2005. Preferential phosphorus leaching from an irrigated grassland soil. European Journal of Soil Science. 56:155–167.

12. Toor, G.S., J.T. Sims, and Z. Dou. 2005. Reducing phosphorus in dairy diets improves farm nutrient balances and decreases the risk of nonpoint pollution of surface and ground waters. Agriculture Ecosystems & Environment. 105:401–411.

11. Toor, G.S., L.M. Condron, H.J. Di, K.C. Cameron, & J.T. Sims. 2004. Impact of farm dairy effluent application on amounts and forms of phosphorus loss from irrigated grassland. New Zealand Journal of Agricultural Research. 47:479–490.

10. Toor, G.S., L.M. Condron, H.J. Di, & K.C. Cameron. 2004. Seasonal fluctuations in phosphorus loss by leaching from a free draining grassland soil. Soil Science Society of America Journal. 68:1429–1436.

9. Toor, G.S., L.M. Condron, H.J. Di, K.C. Cameron, & J.T. Sims. 2004. Assessment of phosphorus leaching losses from a free draining grassland soil. Nutrient Cycling in Agroecosystems. 69:169–184. 

8. Toor, G.S., L.M. Condron, H.J. Di, K.C. Cameron, & B.J. Cade-Menun. 2003. Characterization of organic phosphorus in leachate from a grassland soil. Soil Biology & Biochemistry. 35:1317–1323.

7. Sinaj, S., C. Stamm, G.S. Toor, L.M. Condron, T. Hendry, H.J. Di, K.C. Cameron, & E. Frossard. 2002. Phosphorus exchangeability and leaching losses from two grassland soils. Journal of Environmental Quality. 31:319–330.

6. Bahl, G.S. & G.S. Toor. 2002. Influence of poultry manure on phosphorus availability and the standard phosphate requirement of crop estimated from quantity–intensity relationships in different soils. Bioresource Technology. 85:317–322.

5. Bahl, G.S. & G.S. Toor. 1999. Efficiency of P utilization by sunflower grown on residual P fertility. Bioresource Technology. 67:97–100.

4. Toor, G.S. & G.S. Bahl. 1999. Kinetics of phosphate desorption from different soils as influenced by application of poultry manure and fertilizer phosphorus and its uptake by soybean. Bioresource Technology. 69:117–121.

3. Toor, G.S. & G.S. Bahl. 1997.  Effect of poultry manure addition and phosphorus fertilization on phosphorus adsorption and desorption pattern of soils. Ecological Agriculture: Towards Sustainable Development, Center for Research in Rural and Industrial Development, Chandigarh, India, pp.72-98.

2. Toor, G.S., G.S. Bahl, & A.C. Vig. 1997. Pattern of P availability in different soils as assessed by different adsorption equations. Journal of Indian Society of Soil Science. 45:719–723.

1. Toor, G.S. & G.S. Bahl. 1997. Effect of solitary and integrated use of poultry manure and fertilizer phosphorus on the dynamics of P availability in different soils. Bioresource Technology. 62:25–28.

Nitrogen (21)

For obtaining a PDF copy of the publication, click on the article title:

21. **Yang, Y., M. M. Tfaily, J.L. Wilmoth, & G.S. Toor. 2022. Molecular characterization of dissolved organic nitrogen and phosphorus in agricultural runoff and surface waters. Water Research, 118533. https://doi.org/10.1016/j.watres.2022.118533

20. Ji, W., J. Xiao, G.S. Toor, & Z. Li. 2021. Nitrate-nitrogen transport in streamwater and groundwater in a loess covered region: Sources, drivers, and spatiotemporal variation. Science of the Total Environment, 761, 143278. https://doi.org/10.1016/j.scitotenv.2020.143278

19. *Jani, J., M. Lusk, Y. Yang, & G.S. Toor. 2020. Wet season nitrogen export from a residential stormwater pond. PLoS ONE, 15 (4): e0230908. https://doi.org/10.1371/journal.pone.0230908

18. *Jani, J., Y. Yang, M. Lusk, & G.S. Toor. 2020. Composition of nitrogen in urban residential stormwater runoff: variation in concentrations, loads, and source characterization of nitrate and organic nitrogen. PLoS ONE, 15(2): e0229715. https://doi.org/10.1371/journal.pone.0229715

17. *Lusk, M, G.S. Toor, & P. Inglett. 2020. Organic nitrogen in residential stormwater runoff: Implications for stormwater management in urban watersheds. Science of the Total Environment, 707. 135962. https://doi.org/10.1016/j.scitotenv.2019.135962

16. *Jani, J., G.S. Toor. 2018. Composition, sources, and bioavailability of nitrogen in a longitudinal gradient from freshwater to estuarine waters. Water Research, 137: 344–354.

15. *Lusk, M.G., G.S. Toor, & P.W. Inglett. 2018. Characterization of dissolved organic nitrogen in leachate from a newly established and fertilized turfgrass. Water Research, 131: 52­–61.

14. *Lusk, M.G., G.S. Toor, Y. Yang, S. Mechtensimer, M. De, & T. Obreza. 2017. A review of fate and transport of nitrogen, phosphorus, pathogens, and trace organic chemicals in septic systems. Critical Reviews in Environmental Science & Technology. 47: 455–541. http://dx.doi.org/10.1080/10643389.2017.1327787

13. Toor, G.S., M.L. Occhipinti, Y. Yang, T. Majcherek, D. Haver, & L. Oki. 2017. Managing urban runoff in residential neighborhoods: nitrogen and phosphorus in lawn irrigation driven runoff. PLoS ONE12 (6), e0179151. DOI: 10.1371/journal.pone.0179151

12. *De, M. & G.S. Toor. 2017. Nitrogen transformations in the mounded drainfields of drip dispersal and gravel trench septic systems. Ecological Engineering, 102: 352–360. DOI: 10.1016/j.ecoleng.2017.02.039

11. **Yang, Y. & G.S. Toor. 2017. Sources and mechanisms of nitrate and orthophosphate transport in urban stormwater from residential catchments. Water Research, 112:176–184. DOI: 10.1016/j.watres.2017.01.039.

10. *Lusk, M.G. & G.S. Toor. 2016. Biodegradability and molecular composition of dissolved organic nitrogen in urban stormwater runoff and outflow water from a stormwater retention pond. Environmental Science & Technology, 50:3391–3398DOI: 10.1021/acs.est.5b05714. 

9. *Lusk, M.G. & G.S. Toor. 2016. Dissolved organic nitrogen in urban streams: biodegradability and molecular composition studies. Water Research, 96:225–235. DOI: 10.1016/j.watres.2016.03.060.

8. **Yang, Y. & G.S. Toor. 2016. δ15N and δ18O reveal the sources of nitrate-nitrogen in urban residential stormwater runoff. Environmental Science & Technology, 50: 2881–2889. DOI: 10.1021/acs.est.5b05353. 

7. *De, M. & G.S. Toor. 2016. Mass balance of water and nitrogen in the mounded drainfield of a drip-dispersal septic system. Journal of Environmental Quality, 45:1392–1399. DOI: 10.2134/jeq2016.02.0043.

6. *De, M. & G.S. Toor. 2016. High removal of effluent-borne nitrogen with multiple external electron donors in the engineered drainfield of an advanced septic system. Journal of Environmental Quality, 45:1874–1882. DOI: 10.2134/jeq2016.06.0215.

5. *De, M. & G.S. Toor. 2015. Fate of effluent-borne nitrogen in the mounded drainfield of an onsite wastewater treatment system. Vadose Zone Journal. DOI: 10.2136/vzj2015.07.0096.

4. **Filipovic, V., Toor, G.S., Ondrasek, G. & Kodesova, R. 2015. Modeling water flow and nitrate-nitrogen transport on future golf courses under turfgrass. Journal of Soils and Sediments. 15: 1847-1859. DOI 10.1007/s11368-014-0980-7.

3. **Carey, R.O., G. Hochmuth, C.J. Martinez, T.H. Boyer, M.D. Dukes, G.S. Toor, & J.L. Cisar. 2013. Evaluating nutrient impacts in urban watersheds: Challenges and research opportunities. Environmental Pollution. 173:138-149.

2. **Carey, R.O., G. Hochmuth, C.J. Martinez, T.H. Boyer, V.D. Nair, M.D. Dukes, G.S. Toor, A.L. Shober, J.L. Cisar, L.E. Trenholm, & J.B. Sartain. 2012. Regulatory and resource management practices for urban watersheds: The Florida experienceHORTTECHNOLOGY. 22: 418-429.

1. *Khare, Y.P., C.J. Martinez, & G.S. Toor. 2012. Water quality and land use changes in the Alafia and Hillsborough river watersheds, Florida, USA. Journal of American Water Resources Association. 48:1276-1293.

Carbon (6)

For obtaining a PDF copy of the publication, click on the article title:

6. Toor, G.S., Y. Yang, S. Das, S. Dorsey, & G. Felton. 2021. Soil health in agricultural ecosystems: current status and future perspectives. Advances in Agronomy, 168, 157–201. https://doi.org/10.1016/bs.agron.2021.02.004

5. *Kalev, S., S. Duan, & G.S. Toor. 2021. Enriched dissolved organic carbon export from a residential stormwater pond. Science of the Total Environment, 751, 141773. https://doi.org/10.1016/j.scitotenv.2020.141773

4. **Yang, Y, A. Goldsmith, I. Herold, S. Lecha, & G.S. Toor. 2020. Assessing soil organic carbon in soils to enhance and track future carbon storage. Agronomy, 10(8), 1139; https://doi.org/10.3390/agronomy10081139

3. * Kalev, S. & G.S. Toor. 2020. Concentrations and loads of dissolved and particulate organic carbon in urban stormwater runoff. Water, 12 (4), 1031.https://doi.org/10.3390/w12041031

2. *Banger, K., G.S. Toor, A. Biswas, S.S. Sidhu, & K. Sudhir. 2010. Soil organic carbon fractions after 16-years of applications of fertilizers and organic manure in a Typic Rhodalfs in semi-arid tropics. Nutrient Cycling in Agroecosystems. 86: 391–399.

1.*Banger, K., S.S. Kukal, G.S. Toor, & K. Sudhir, & T. Hanumanthraju. 2009. Impact of long-term additions of chemical fertilizers and farm yard manure on carbon and nitrogen sequestration under rice-cowpea cropping system in semi-arid tropics. Plant and Soil. 318: 27–35.

General water quality (21)

For obtaining a PDF copy of the publication, click on the article title:

21. Spargo, J. T., Lyons, S. E., Clark, J. D., Osmond, D. L., Parvej, R. Md., Pearce, A. W., Slaton, N. A., Saffire, D., Alford, S., Allen, T., Arnall, B., Buob, T., Camberato, J. J., Cardon, G., Culman, S, W., Davenport, J. R., Fernandez, F. G., Florence, R., Flynn, R., Franzen, D., Geisseler, D., Grove, J., Hardy, D., Heckman, J., Hopkins, B., Hoskins, B., Hue, N. V., Huluka, G., Jones, C., Jones, K., Kaiser, D. E., Kalmbach, B., Ketterings, Q. M., Laboski, C. A. M., Lessl, J., Lucas, E., Maguire, R., Mahler, R., Mallerino, A., Margenot, A., McGrath, J. M., Miller, R., Moore, A. D., Morris, T. F., Mylavarapu, R., Nathan, M., Nelson, N. O., Norton, J., Pena-Yewtukhiw, E., Pettinelli, D., Provin, T., Radin, A., Ross, D., Saunders, O., Self, J., Shober, A. L., Sonon, L., Sotomayor, D. R., Stammer, A., Steinke, K., Toor, G., Walworth, J., Wang, J. J., Wortmann, C., Zhang, H. (2022). A survey to evaluate the current status of land grant university and state department of agriculture soil fertility recommendations and analytical methods. Ag Data Commons. https://doi.org/10.15482/USDA.ADC/1526506

20. Angelakis, A.N., M. Valipour, K.-H. Choo, A.T. Ahmed, A. Baba, R. Kumar, G.S. Toor, & Z. Wang. 2021. Desalination: From Ancient to Present and Future. Water, 13, 2222. https://doi.org/10.3390/w13162222

19. *Darre, N.C, G.S. Toor. 2018. Desalination of water: a review. Current Pollution Reports. 4, pages104–111. https://doi.org/10.1007/s40726-018-0085-9 

18. *Kalev, S.D. & Toor, G.S. 2018. The Composition of Soils and Sediments. In Torok, B. and T. Dransfield, eds., Green Chemistry: An Inclusive Approach. 1st Edition. Elsevier, pp 339–357.

17. *Lusk, M.G. & G.S. Toor. 2017. Optimizing Hydrologic Properties of Urban Soils. In Lal, R. and B.A. Stewart, eds., Advances in Soil Science: Urban Soils. CRC Press, pp 199–214.

16. Toor, G.S., L. Han, & C.D. Stanley. 2013. Temporal variability in water quality parameters-a case study of drinking water reservoir in Florida, USA. Environmental Monitoring and Assessment. 185: 4305-4320.

15. *Chahal, M.K., G.S. Toor, & B.M. Santos. 2012. Chemical characterization of tomato industry wastewater, Florida, United States. Journal of Water Resource and Protection. 4:107-114.

14. *Hagan, D. C. Dobbs, N. Timilsina, F. Escobedo, G.S.Toor, & M. Andreu. 2012. Anthropogenic effects on the physical and chemical properties of subtropical coastal urban soils. Soil Use and Management. 28:78-88.

13. **Carey, R.O., G. Hochmuth, C.J. Martinez, T.H. Boyer, V.D. Nair, M.D. Dukes, G.S. Toor, A.L. Shober, J.L. Cisar, L.E. Trenholm, & J.B. Sartain. 2012. A Review of Turfgrass Fertilizer Management Practices: Implications for Urban Water QualityHORTTECHNOLOGY. 22: 280-291.

12. Abd-Elrahman, A., M. Croxton, R. Pande-Chettri, G.S. Toor, S. Smith, & J. Hill. 2011. In-situ estimation of water quality parameters in freshwater aquaculture ponds using hyperspectral imaging system. ISPRS Journal of Photogrammetry and Remote Sensing. 60:463–472.

11. Stanley, C.D. & G.S. Toor. 2010. Florida commercial horticultural production:  constraints limiting water and nutrient use efficiency. HortTechnology. 20: 89–93.

10. Toor, G.S., R.D. Harmel, B.E. Haggard, & G. Schmidt. 2008. Evaluation of regression methodology with low-frequency water quality sampling to estimate constituent loads for ephemeral watersheds in Texas. Journal of Environmental Quality. 37:1847–1854.

9. Verma, V.K., L.B. Patel, G.S. Toor, P.K. Sharma, & V. Singh. 2005. Dynamics and spatial distribution of soluble salts in ground waters with special reference to their suitability for irrigation in Faridkot District of Punjab, India.  Ecology, Environment and Conservation. 11:119–122.

8. Verma, V.K., L.B. Patel, G.S. Toor, & P.K. Sharma. 2005. Spatial distribution of macronutrients in soils of arid tract of Punjab, India. International Journal of Agriculture and Biology. 7:285–297.

7. Verma, V.K., P.K. Sharma, V. Singh, L.B. Patel, & G.S. Toor. 2004. Hydrochemical facies of ground waters of Southwestern Punjab, India in relation to their suitability for irrigation. Asian Journal of Microbiology, Biotechnology and Environmental Sciences. 6:379–381.

6. Thind, H.S., C.L. Arora, & G.S. Toor. 2004. Nutrients return through leaf litter and their relations with poplar growth under different treatments of N, irrigation and inter-cropping. Indian Journal of Agroforestry. 62: 41–45.

5. Verma, V.K., L.B. Patel, P.K. Sharma, G.S. Toor, & V. Singh. 2003. Evaluation, characterization and management of soil - water related constraints for sustainable agriculture: an integrated approach using remote sensing and GIS. International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences. 34:280–283.

4. Patel, L.B., V.K. Verma, G.S. Toor, & P.K. Sharma. 2001. Ground water quality for irrigation: Its assessment and management in District Mansa, Punjab (India). Ecology, Environment and Conservation. 7:315–318.

3. Patel, L.B., V.K. Verma, G.S. Toor, & P.K. Sharma. 2000. Beneficial plant nutrient supply from ground waters of arid tract of Punjab.  Ecology, Environment and Conservation. 6:105–108.

2. Patel, L.B., V.K. Verma, G.S. Toor, & P.K. Sharma. 2000. Hydrochemistry of ground waters of southern Punjab, India in relation to their suitability for irrigation.  Ecology, Environment and Conservation. 6:179–183.

1. Verma, V.K., L.B. Patel, P.K. Sharma, G.S. Toor, & C. Singh. 2000. Integrated approach for evaluation, characterisation and management of soil and water related constraints in arid environment of Punjab, India. Asian Journal of Microbiology, Biotechnology and Environmental Sciences. 2:43–50.

Trace metals (8)

For obtaining a PDF copy of the publication, click on the article title:

8. **Dhaliwal, S.S., G.S. Toor, S. Newman, & T.Z. Osborne. 2018. Trace metals in the soils of Water Conservation Area of Florida Everglades: consideration for ecosystem restoration. Journal of Soils and Sediments, 18: 342-351. DOI: 10.1007/s11368-016-1459-5.

7. **Zhan, F., He, Y., Li, T., Yang, Y.Y., Toor, G.S. & Zhao, Z. 2015. Subcellular distribution and chemical forms of cadmium in a dark septate endophyte (DSE), Exophiala pisciphila. Environmental Science and Pollution Research. 22:17897-17905.

6. **Yang, Y. & Toor, G.S. 2015. Fate of nutrients, trace metals, bacteria, and pesticides in nursery recycled water. Journal of Water Resource and Protection.7:293-299. DOI:10.4236/jwarp.2015.74023.

5. **Zhan, F., He, Y., Li, T., Yang, Y.Y., Toor, G.S. & Zhao, Z. 2015. Tolerance and antioxidant response of a dark septate endophyte (DSE), Exophiala pisciphila, to cadmium stress. Bulletin of Environmental Contamination and Toxicology. 94: 96-102. DOI. 10.1007/s00128-014-1401-8.

4. **Wang, H., Y. Dong, Y. Yang, G.S. Toor, & X. Zhang. 2013. Changes in heavy metal contents in animal feeds and manures in an intensive animal production region of China. Journal of Environmental Sciences. 25: 2435-2442.

3. *Chahal, M.K., G.S. Toor, & P. Brown. 2010. Trace metals and polycyclic aromatic hydrocarbons in an urbanized area of Florida. Soil and Sediment Contamination. 19:419–435.

2. *Chahal, M.K. & G.S. Toor. 2011. Trace metal leaching in a spodosol irrigated with tomato packinghouse wastewater. Soil Use and Management. 27:480-490.

1. Toor, G.S., B.E. Haggard, & A.M. Donoghue. 2007. Water extractable trace elements in poultry litters and granulated products. Journal of Applied Poultry Research. 16:351–360.

Organic contaminants (16)

For obtaining a PDF copy of the publication, click on the article title:

16. *Rodríguez-Jorquera, I. A., R. C. Colli-Dula, K. Kroll, B.M. Jayasinghe, M.V.P. Marco, C. Silva-Sanchez, G. S. Toor, & N.D. Denslow. 2019. Blood transcriptomics analysis of fish exposed to perfluoro alkyls substances: Assessment of a non-lethal sampling technique for advancing aquatic toxicology research. Environmental Science & Technology, 53: 1441–1452. DOI: 10.1021/acs.est.8b03603

15. *Rodríguez-Jorquera, I., P. Siroski, W. Espejo, J. Nimptsc, S. Woelfl, P.G. Choueri, R.B. Choueri, C. Moraga, M. Mora, & G.S. Toor. 2017. Latin American Protected Areas: Protected from Chemical Pollution? Integrated Environmental Assessment and Management, 13:360–370. DOI: 10.1002/ieam.1839.

14. *Rodríguez-Jorquera, I, N. Vitale, L. Garner, C. Galbán, N. Duque-Wilckens, N, & G.S. Toor. 2017. Contamination of the Upper Class: Occurrence and Effects of Chemical Pollutants in Terrestrial Top Predators. Current Pollution Reports, 3: 206-219

13. *Lusk, M.G., G.S. Toor, Y. Yang, S. Mechtensimer, M. De, & T. Obreza. 2017. A review of fate and transport of nitrogen, phosphorus, pathogens, and trace organic chemicals in septic systems. Critical Reviews in Environmental Science & Technology. 47: 455–541. http://dx.doi.org/10.1080/10643389.2017.1327787

12. **Yang, Y., G.S. Toor, P.C. Wilson, & C.F. Williams. 2017. Micropollutants in groundwater from septic systems: Transformations, transport mechanisms, and human health risk assessment. Water Research. 123: 258–267. DOI: 10.1016/j.watres.2017.06.054

11. *Colon, B. & G.S. Toor. 2016. A review of uptake and translocation of pharmaceuticals and personal care products by food crops irrigated with treated wastewater. Advances in Agronomy, 140:75–100. DOI: 10.1016/bs.agron.2016.07.001.

10. **Yang, Y., G.S. Toor, P.C. Wilson, & C.F. Williams. 2016. Septic systems as hot-spots of pollutants in the environment: Fate and mass balance of micropollutants in septic drainfields. Science of the Total Environment, 566–567:1535–1544. DOI: 10.1016/j.scitotenv.2016.06.043

9. *Rodriguez-Jorquera, I., C. Silva-Sanchez, M. Strynar, N.D. Denslow, & G.S. Toor. 2016. Footprints of urban micro-pollution in protected areas: investigating the longitudinal distribution of perfluoroalkyl substances in wildlife preserves. PLoS ONE, 11(2): e0148654. DOI: 10.1371/journal.pone.0148654.

8. *Rodriguez-Jorquera, I., Kroll,K.J., Toor, G.S.  & Denslow, N.D. 2015. Transcriptional and physiological response of fathead minnows (Pimephales promelas) exposed to urban waters entering into wildlife protected areas. Environmental Pollution. 199: 155-165. DOI: 10.1016/j.envpol.2015.01.021.

7. **Yang, Y., Toor, G.S. & Williams, C.F. 2015. Pharmaceuticals and organochlorine pesticides in sediments of an urban river in Florida, USA. Journal of Soils and Sediments DOI: 10.1007/s11368-015-1077-7

6. **Wang, H.Y., H. Wang, L. Li Tang, Y. H. Dong, L. Zhao, & G.S. Toor. 2014. Sorption characteristics of cyromazine and its metabolite melamine in typical agricultural soils of China. Environmental Science and Pollution Research. 21: 979-985.

5. *Pannu, M.W., G.S. Toor, G.A. O’Connor, & P.C. Wilson. 2012. Toxicity and bioaccumulation of biosolids-borne triclosan in food crops. Environmental Toxicology & Chemistry. 31: 2130-2137.

4. *Pannu, M.W., G.A. O'Connor, & G.S. Toor. 2012. Toxicity and bioaccumulation of biosolids-borne triclosan in terrestrial organismsEnvironmental Toxicology & Chemistry.  31:646-653.

3. *Waria, M., G.A. O’Connor, & G.S. Toor. 2011. Biodegradation of triclosan in biosolids-amended soils. Environmental Toxicology and Chemistry. 30:2488-2496.

2. *Chahal, M.K., G.S. Toor, & P. Brown. 2010. Trace metals and polycyclic aromatic hydrocarbons in an urbanized area of Florida. Soil and Sediment Contamination. 19:419–435.

1. *Banger, K., G.S. Toor, T. Chirenje, & L. Ma, 2010. Polycyclic aromatic hydrocarbons in urban soils of different land uses in Miami, Florida. Soil and Sediment Contamination. 19: 231–243.

EXTENSION

The overall goal of my extension program is to sustain agricultural production and improve the water quality in water bodies in Maryland and Chesapeake Bay by educating, informing, and empowering stakeholders. These efforts will improve stakeholder’s decision-making ability with regard to crop production management practices in the region.

Our group extends knowledge generated from research to educate farmers, county extension faculty, environmental groups, local and state government agencies, policy makers, and citizens about ways to sustain agriculture and protect water quality in the Chesapeake Bay. Information used in this program is synthesized from the research conducted in the group and in collaborations with colleagues from the region. The knowledge and awareness of critical soil processes that drive nutrient cycling, transformations, and loss among farmers, local, state, and federal governmental agencies, environmental groups, and citizens will lead to better management of nutrients in the agricultural production systems and decrease the risk of losses to protect and restore water quality in the Chesapeake Bay.

The specific objectives of my Extension program are to:

  • Provide statewide leadership and guidance to farmers, commodity groups, stakeholders, environmental groups, and state and federal agencies on nutrient management and water quality connections in the Chesapeake Bay.

  • Develop cost-effective and innovative tools and practices to manage nitrogen and phosphorus in the plant root-zone and prevent water quality impairment in water bodies.

Extension Publications (total published: 37)

Extension Publications (total published: 37)

For obtaining a PDF copy of the publication, click on the article title:

Peer-reviewed Extension Publications (32):

37. Kalmbach, B. & G.S. Toor. 2021. Soil Sampling for Optimizing Agricultural Production in Maryland. FS-1184. University of Maryland Extension, College Park, MD.

36. Toor, G.S., B. Kalmbach, P. Shipley, & D. Ruppert. 2021. Converting among Soil Test Analyses Frequently Used in Maryland. SFM-4, pp4. University of Maryland Extension, College Park, MD.

35. Kalmbach, B., G.S. Toor, & D. Ruppert. 2020. Soil Fertility Recommendations: Nitrogen, Phosphorus, and Potassium Requirements of Miscanthus. EB-443, pp 8. University of Maryland Extension, College Park, MD.

34. **Yang, Y., Rodriguez-Jorquera, I. & G.S. Toor. 2015. Contaminants in the Urban Environment: Microplastics. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss649

33. *Rodriguez-Jorquera, I., Yang, Y. & G.S. Toor. 2015. Contaminants in the Urban Environment: Bisphenol-A. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss648

32. **Yang, Y. & G.S. Toor. 2015. Contaminants in the Urban Environment: Dioxins. University of Florida– IFAS, Gainesville, FL. https://edis.ifas.ufl.edu/ss642

31. **Yang, Y. & G.S. Toor. 2014. Contaminants in the Urban Environment: Pharmaceuticals and Personal Care Products-Part 1. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss631

30. **Yang, Y. & G.S. Toor. 2014. Contaminants in the Urban Environment: Pharmaceuticals and Personal Care Products-Part 2. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss632

29. *Rodriguez-Jorquera, I. & G.S. Toor. 2014. Contaminants in the Urban Environment: Perfluoroalkyl Substances. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss633

28. *Rodriguez-Jorquera, I. & G.S. Toor. 2014. Contaminantes en el Medio Ambiente Urbano: Los Perfluoroalquilos. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss644

27. Shober, A.L., C. Wiese, & G.S. Toor. 2013. Preplant soil assessment for new residential landscapes in Florida. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss534

26. Toor, G.S. M.K. Chahal, & B.M. Santos. 2012. Solutions for managing tomato culls in Florida tomato packinghouses. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss572

25. Toor, G.S. M.K. Chahal, & B.M. Santos. 2012. Solutions for managing wastewater in Florida tomato packinghouses. University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss573

24. *Winans, K., S. Speas-Frost, M. Jerauld, M. Clark, & G.S. Toor. 2012. Small-scale natural wastewater treatment systems: principles and regulatory framework. University of Florida-IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss566

23. Toor, G.S. & M. Lusk. 2011. Reclaimed Water Use in the Landscape: What’s in reclaimed water and where does it go?  University of Florida– IFAS, Gainesville, FL.  http://edis.ifas.ufl.edu/ss542

22. Toor, G.S. & M. Lusk. 2011. Reclaimed Water Use in the Landscape: Constituents of concern in reclaimed water. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss543

21. Toor, G.S. & M. Lusk. 2011. Reclaimed Water Use in the Landscape: Managing salinity, sodicity, and specific ion toxicity in reclaimed water irrigated sites. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss545

20. Toor, G.S. & M. Lusk. 2011. Reclaimed Water Use in the Landscape: Understanding landscape irrigation water quality tests. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss546

19. Toor, G.S. & M. Lusk. 2011. Reclaimed Water Use in the Landscape: Frequently asked questions about reclaimed water. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss544

18. Toor, G.S., M. Lusk, & T. Obreza. 2011. Onsite sewage treatment and disposal systems:  overview. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss549

17. Toor, G.S., M. Lusk, & T. Obreza. 2011. Onsite sewage treatment and disposal systems:  nitrogen. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss550

16. *Lusk, M., G.S. Toor, & T. Obreza. 2011. Onsite sewage treatment and disposal systems: phosphorus. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss551

15. *Lusk, M., G.S. Toor, & T. Obreza. 2011. Onsite sewage treatment and disposal systems: bacteria and protozoa. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss552

14. *Lusk, M., G.S. Toor, & T. Obreza. 2011. Onsite sewage treatment and disposal systems: viruses. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss553

13. Toor, G.S., M. Lusk, & T. Obreza. 2011. Onsite sewage treatment and disposal systems:  trace organic chemicals. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss554

12. Martinez, C., M.W. Clark, G.S. Toor, & G.J. Hochmuth. 2011. Accounting for nutrients in reclaimed water. University of Florida – IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ae479

11. *Hagan, D., F. Escobedo, G.S. Toor, H. Mayer, J. Klein, & C. Dobbs. 2010. Soil bulk density and organic matter in urban Miami-Dade county, Florida. University of Florida – IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss537

10. *Hagan, D., F. Escobedo, G.S. Toor, C. Dobbs, & M. Andreu. 2010. Key physical and chemical properties of Tampa’s urban soils. University of Florida – IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss536

9. Toor, G.S. & D. Rainey. 2009. History and current status of reclaimed water use in Florida. University of Florida– IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/ss520

8. Toor, G.S., & A.L. Shober. 2008. Soils and fertilizers for Master Gardeners: Soil organic matter and organic amendments. SL273/MG454. University of Florida – IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/MG454

7. Shober, A.L., & G.S. Toor. 2008. Soils and fertilizers for Master Gardeners: Urban soils and their management issues. SL276/MG456. University of Florida – IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/MG456

6. Sartain, J.B., L.T. Trenholm, E.F. Gilman, T.A. Obreza, & G.S. Toor. 2008. Frequently asked questions about landscape fertilization for Florida-friendly landscaping ordinances. ENH1115/WQ143. University of Florida – IFAS, Gainesville, FL. http://edis.ifas.ufl.edu/WQ143

Featured Magazine Article (2)

5. Toor, G.S. & Sims, J.T. 2016. Managing legacy and new sources of phosphorus to reduce leaching in mid-Atlantic soils. Crops and Soils. September–October Issue: 40–47. doi:10.2134/cs2016.49.0512

4. Bartens, J., N. Basta, S. Brown, C. Cogger, B. Dvorak, B. Faucette, P. Groffman, G. Hettairachchi, K. McIvor, R. Pouyat, G.S. Toor, & J. Urban. 2012. Soils in the City: A Look at Soils in Urban Areas. CSA News. 57 (Issue 8): 4-13. Published by CSSA-SSSA-ASA. Available online at: https://www.agronomy.org/files/publications/csa-news/soils-in-the-city.pdf

Other Extension/Teaching Publications–Peer reviewed (3)

3. Toor, G.S., R.O. Maguire, & J.T. Sims, J.T. 2004. Grazing Management.  In Phosphorus Best Management Practices, Southern Extension Research Activity–Information Exchange Group. http://www.sera17.ext.vt.edu//Documents/BMP_grazing_management.pdf

2. Hyde, J.E., & G.S. Toor. 2004. Where in the world is hydra electron? Lesson plan for K-8 grades. http://ag.udel.edu/iseq/lessonplans.htm.

1. Verma, V.K., P.K. Sharma, L.B. Patel, D.C. Loshali, & G.S. Toor. 2000. Natural resource management for sustainable development using remote sensing technology - a case study. National Natural Resources Management System, 24, 41-49.

TEACHING

I am actively involved in teaching, advising, and mentoring students and visiting students and scientists. Teaching is important to me for two reasons. First, I am eager to educate students and scholars about the complex interactions between soil processes, nutrients, water quality, and environmental sustainability. Second, soil and water are some of our most important natural resources; thus, all forms of soil and water pollution need to be prevented or corrected.

My goal as a teacher is to synthesize, evaluate, and integrate the latest research findings to introduce students to a variety of topics in the subject matter. My goal as an academic advisor is to provide students with the necessary skills and knowledge that will allow them to become outstanding professionals and productive members of society.

I currently teach undergraduate and graduate-level classes, which include:

  • ENST 471, Capstone I (Fall)

  • ENST 472, Capstone II (Spring)

  • ENST 689, Special Topics (Fall, Spring)

  • ENST 799, Research Credits (Fall, Spring)

Previously, I have taught various classes over 10+ years of an academic career at the University of Florida. Some of these include:

  • SWS 4204, Urban Soil and Water Systems

  • SWS 6209, Advanced Urban Soil and Water Systems

  • SWS 3022L, Introduction to Soils in the Environment Lab

  • SWS 6905, Special Problems

  • SWS 6910, Supervised Teaching

  • SWS 6971, Masters Research

  • SWS 7979, Advanced Research

  • SWS 7980, Doctoral Research

    SERVICE

    Editorial Boards

    • Section Editor, Current Pollution Reports (Springer) journal (2016-current)

    • Academic Editor, PLoS ONE (2018-current)

    • Academic Editor, Water (2020-current)

    • Associate Editor, Journal of Environmental Quality (2008-2014)

    Leadership Activities

    • Member, Board of Directors of American Society of Agronomy (2022-current)

    • Member, Science-Policy Committee of Soil Science Society of America (2020-current)

    • Member, ASA-CSSA-SSSA Book and Multi-Media Publishing Committee (2014-present)

    • Appointed Member of the State of Maryland Nutrient Management Committee by Secretary of Agriculture (2017-present)

    • Appointed Member of the State of Maryland Phosphorus Management Tool Committee by Secretary of Agriculture (2017-present)

    • Member, Faculty Research Council, College of Agricultural and Natural Resources, University of Maryland (2020-present)

    • Member, United States Environmental Protection Agency, Chesapeake Bay Program Agriculture Workgroup (2019-present)

    • Chair, Urban & Anthropogenic Soils Division of Soil Science Society of America (Jan-Dec 2014)

    • Chair, Nominations Committee for Urban & Anthropogenic Soils Division Officers of Soil Science Society of America (Jan-Dec 2014)

    • Member, Nominations for Soil Science Society of America President-Elect Committee (Jan-Dec 2014)

    • Member, SSSA Annual meeting Program Planning Committee (Jan-Dec 2014)

    • Past Chair, Urban & Anthropogenic Soils Division of Soil Science Society of America (Jan-Dec 2015)

    • Past Chair, Nominations Committee for Urban & Anthropogenic Soils Division Officers of Soil Science Society of America (Jan-Dec 2015)

    • Member, Soil Science Society of America S594 Urban Soils Committee (2012-2013)

    • Member, American Society of Agronomy K-12 Committee (2010-2012)

    Team Members Info

    The below tabs include information about the current team members and various lab instruments and associated analyses capabilities in the laboratory.

    Current Team Members:

    Professional-Track Faculty:

    Ruth Cassilly

    Faculty Specialist

    Located at Chesapeake Bay Office of U.S. Environmental Protection Agency in Annapolis, MD

    Loretta Collins

    Faculty Specialist

     Located at Chesapeake Bay Office of U.S. Environmental Protection Agency in Annapolis, MD

    Mark Dubin

    Senior Faculty Specialist

    Located at Chesapeake Bay Office of U.S. Environmental Protection Agency in Annapolis, MD

    Dr. Shuiwang Duan

    Assistant Research Scientist 

    (2019-present)

    Taylor Roswall

    Faculty Assistant

    (2021-present)

    Post-doctoral Researchers:

    Dr. Charles Burgis

    Postdoctoral Research Associate

    (2020-present)

    Graduate Students:

    Bradley Kennedy

    Ph.D. Student

    (2021-present)

    Emileigh Lucas

    Ph.D. Student

    (Fall 2022 onwards)

    Other Researchers:

    Dr. Patricia Steinhilber

    Faculty Specialist

    (retired Coordinator of Agricultural Nutrient Management Program)

    Dr. Fajun Sun

    Lab Manager/Agricultural Technician Supervisor

    Undergraduate Research Assistants:

    Autumn McCarthy

    Junior

    Majoring in Biochemistry

    Fiona Quin Zabel

    Sophomore

    Majoring in ENST and Chemistry with a minor in Statistics

    Previous team

    Professional Track Faculty:

    • Dr. Yun-Ya YangPrincipal Faculty Specialist (2018-2021). Currently Senior Scientist at Andes Ag in California.

    Staff:

    • Stanley SchlosnagleAgricultural Technician Supervisor (2017-2021). Retired and enjoying life since May 2021.

    PhD Students:

    • Jariani Jani, Ph.D. Student, Soil and Water Science, 2018. Currently Researcher at University of Malaya, Malaysia
    • Mary Lusk, Ph.D. Student, Soil and Water Science, 2015. Currently Assistant Professor and Extension Specialist, University of Florida, Balm, FL
    • Mriganka De, Ph.D. Student, Soil and Water Science, 2015. Currently Assistant Professor, Minnesota State University, MN
    • Ignacio Rodriguez, Ph.D. Student, Interdisciplinary Ecology, 2014. Currently Executive Director of Wetland Center at University of Chile, Valdivia, Chile
    • Manmeet Waria, Ph.D. Student, Soil and Water Science, 2011. Currently Senior Scientist at Orange County Water District, Los Angeles, CA

    MS Students:

    • Taylor Roswall, M.S. Student, Soil and Watershed Science, 2021. Currently Faculty Assistant, Department Environmental Science and Technology, College Park, MD
    • Kristi Dobra, M.S. Student, Soil and Water Science, 2018. Currently PhD Student at University of Pittsburgh and Senior Project Manager, US Army Corps, Pittsburgh, PA
    • Stefan Kalev, M.S. Student, Soil and Water Science, 2017. Currently Environmental Scientist, Charlotte County, FL
    • Matthew Jablonski, M.S. Student, Soil and Water Science, 2017. Currently Supervisor at South Florida Water Management District, Brooksville, FL
    • Michael Mertens, M.S. Student, Soil and Water Science, 2017. Currently Staff at Florida Department of Environmental Protection, Orlando, FL
    • Natasha Darre, M.S. Student, Soil and Water Science, 2017. Currently Staff at NASA Kennedy Space Center, Cape Canaveral, FL
    • Sara Mechtensimer, M.S. Student, Soil and Water Science, 2015. Currently Environmental Specialist at Florida Power and Light, West Palm Beach, FL
    • Josefin Edeback-Hirst, M.S. Student, Soil and Water Science, 2015. Currently Senior Environmental Engineer, Hazen & Sawyer, Tampa, FL
    • Bethzaida Colon, M.S. Student, Soil and Water Science, 2015. Currently Consultant at USAID, Washington DC
    • Stephanie McLean, M.S. Student, Soil and Water Science, 2015. Currently Environmental Consultant, Atlanta, GA
    • Marti Occhipinti, M.S. Student, Soil and Water Science, 2012. Currently in NC
    • Kamaljit Banger, M.S. Student, Soil and Water Science, 2010. Currently Post-doctoral Researcher at the University of Guelph, Canada
    • Maninder Chahal, M.S. Student, Soil and Water Science, 2010. Currently Ph.D. Student at Washington State University, Pullman, WA
    • Lori Clark, M.S. Student, Soil and Water Science, 2008. Currently Staff at Washington State Department of Ecology, WA

    Undergraduate Students:

    • Erin Rogers (Fall 2021)
    • Ante Rosales (Spring 2021)
    • Avi Goldsmith, ENST (2018-2019)
    • Ilana Herold, ENST (2018-2019)
    • Sebastian Lecha, ENST (2018-2019)
    • Philip Schwartz, ENST (2017-2018)
    • Yasmine Darwish, ENST (2017-2018)
    • George Gaylord, ENST (2017-2018)
    • Kristen Webb, ENST (2017-2018)

    Lab Instruments

    The following instruments to analyze nutrient and various isotopes in soil, sediment, plant, water samples are available in our lab:

    • Lachat for nutrient analysis (nitrogen, phosphorus species) in extracted samples from soil and sediment, and water samples

    • Shimadzu TOC/L for analysis of DOC, TOC, TDN, and TN in water samples

    • Delta V Isotope Ratio Mass Spectrometer, with EA, Gas Bench, Denitification Kit for analysis of:

      • total carbon, total nitrogen, 13C, 15N in solid soil, sediment, and plant samples

      • dD and 18O/16O in water samples

      • dO of phosphate in water, solid extract samples

      • 15N and 18O of nitrate in water samples

    NEWS

    Explore the following sections to learn about new research and extension publications, new personnel in the laboratory, and current open positions.

    New Personnel and Projects

    • April 2022: Dr. Toor is a sole PI of a new award (>$3.2 million) from the United States Environmental Protection Agency. The overall goal of this project is to protect and restore the Chesapeake Bay ecosystem through continued technical support to address water-quality restoration goals and maintain public awareness of Chesapeake Bay restoration. Three non-tenure-track faculty have been hired to undertake various activities of this complex project with stakeholders spread across the Chesapeake Bay Watershed of ~64,000 square miles, six states (MD, NY, PA, DE, VA, WVA) and Washington DC, and population of >18 million people.

    • January 2022: We welcomed three new undergraduate research assistants. Fiona Quin Zabel, a sophomore majoring in ENST and Chemistry, with a minor in Statistics. Quin will be working on the biosolids phosphorus project with Taylor Roswall. Autumn McCarthy, a junior majoring in Biochemistry, will be working on the soil organic carbon project with Emileigh Lucas. We also have new additions with two capstone students, Orman Morton, and Mackenzi Wintermoyer,  seniors majoring in ENST and working on sediment and particulate phosphorus loss in agricultural landscapes with Dr. Charles Burgis. Welcome, Quin, Autumn, Orman, and Mackenzi to the group!

    • December 2021: We bode farewell to our colleague Dr. Yun-Ya Yang, who has been an integral part of our group since 2018. Dr. Yang is heading out to the silicon valley in California to take a Senior Scientist position in private industry (https://www.andes.bio/). She will continue her nutrient and carbon capture work to solve pressing issues in modern agriculture. Congratulations and Best Wishes, Yun-Ya!

    • November 2021: Dr. Toor received funding from Metropolitan Washington Council of Governments to investigate the fate of phosphorus in biosolids-amended soils. Taylor Roswall will be coordinating this project with assistance from undergraduate assistant.

    • October 2021: Dr. Fajun Sun, joins our group as a Lab Manager/Agricultural Technician Supervisor. She recently completed a Ph.D. in Geochemistry from Florida State University. In her new role, Fajun will be providing us lab support in terms of various nutrients, carbon, and isotopes analyses in the lab, and as time permits, she may start a new line of research in agricultural ecosystems. Welcome, Fajun! We’re very excited to have you here in the group and our department.

    • August 2021: Bradley Kennedy joins us as a new Ph.D. student on the USDA-NIFA Sustainable Agricultural Systems project. Bradley received a BS in Natural Resources from Cornell University and an MS in Agriculture from the University of Copenhagen. She was Research Associate at Rich Earth Institute in Vermont before joining us. Bradley's dissertation research will focus on optimzing nitrogen in agricultural production systems to reduce losses to water bodies. Welcome, Bradley to the group!

    • May 2021: Congratulations to Taylor Roswall for graduating with an MS degree in Soil and Watershed Science. Taylor's thesis was on Quantification of Water Extractable Phosphorus Pools in Soils and Manures to Predict Phosphorus Loss. She has already published one paper from her thesis and working on submitting the second paper soon. Taylor is now working as a Faculty Assistant in our group, conducting field research on nutrient losses. Welcome aboard in a new role, Taylor!

    • January 2021: Dr. Toor and Prof. Zhi Li (Northwest A&F University) are editing a special issue collection of peer-reviewed articles for the journal Water on the topic area of "Nitrogen and Phosphorus in Surface- and Ground-water: Sources, Mechanisms, Processes, and Pathways." More details about the collection and process to submit manuscripts can be found at this weblink: mdpi.com/si/74143

    • January 2021: Dr. Isis Stacanelli Pires Chagas Scott joins us as a Postdoctoral Researcher in the nutrient remediation project using Miscanthus and other buffers on the Delmarva Peninsula. She is jointly supervised by Dr. Greg McCarty, USDA-ARS and Dr. Dean Hively, USGS. Isis (pronounced Izzys) holds an MS in Agronomy and Soil Science and a PhD in Agricultural Engineering, both from Purdue University. Welcome, Isis, to the group!

    • October 2020: Dr. Toor received grants from USDA-ARS and USDA-NRCS to evaluate environmental risks and benefits of grass buffer strips for nutrient remediation on the Delmarva Peninsula.

    • July 2020: Dr. Charles Burgis joins us as a Postdoctoral Researcher in the Phosphorus project funded by USDA-NIFA and Maryland Department of Agriculture. He received an MS and PhD in Environmental Engineering from the University of Virginia. Welcome, Charles, to the group!

    • April 2020: Dr. Shuiwang Duan joins us as Assistant Research Scientist in nutrients project funded by USDA-NIFA and Maryland Department of Agriculture. He received a PhD in Biogeochemistry and Water Quality from the University of Louisiana and has been most recently working in the Geology Department at UMD. Welcome, Shuiwang, to the group!

    • March 2020: Dr. Toor is part of a large inter-disciplinary proposal funded by USDA-NIFA Sustainable Agricultural Systems grant. Check this weblink for information about the project: https://extension.umd.edu/news/creating-sustainable-future-chesapeake-bay-watershed-and-its-people

    • February 2020: Dr. Toor received grants from the Maryland Department of Agriculture and USDA-NIFA to investigate phosphorus losses from agricultural landscapes and develop the next generation of phosphorus index for the state of Maryland.

    • January 2020: Drs. Toor and Yang along with Keith Paustian from Colorado State University received a grant from Harry R. Hughes Center for Agroecology to fine-tune and develop a tool to quantify and track soil organic carbon in Maryland soils.

    New Research Articles

    • New article by former MS student, and now environmental law student Taylor Roswall, in Chemosphere (8.9 impact factor) on our favorite nutrient—phosphorus (P). She investigated the transport of P in soils amended various poultry litters and products such as granulated litter+urea. Here is a plot twist: Rather than adding litters on total nitrogen (N)—that’s what most of the world does—to get full N or total P, which is recommended or regulated in areas where soil P levels are high such as in the Chesapeake Bay Watershed; the poultry litters were added based on P that could be extracted with water (called water-extractable P)—why? Because water will extract a portion of P that will be taken up by plants and also lost in runoff and leaching. But lab extractions are tricky—as dictated by solid-to-water ratios. Several cool points: 1) lab extractions to determine soluble P do not simulate field rainfall events, so the ratios should be carefully used in interpreting the data and making conclusions; 2) if all litters are applied on a similar amount of P extracted with water, the risk of P loss can be easily compared and contrasted; 3) the use of granulated poultry litter + urea balances N and P so there is no surplus of P in soils and this can help prevent legacy P buildup in soils and/or could be used in moderation in regions with legacy P (to replace P taken up by crops). Side notes to all the fertilizer manufacturers: why not make fertilizer with an N:P ratio of ~8:1—that’s what most crops need? Full reference: Roswall, T., B.E. Haggard, & G.S. Toor. 2022. Fate and transformations of dissolved phosphorus forms in runoff: Effect of poultry litter and products extracted with variable water extraction ratios. Chemosphere, 308, 136220. https://doi.org/10.1016/j.chemosphere.2022.136220  

    • New Article by 1st semester PhD student Emileigh Lucas (what a great way to start grad school!) in Chemosphere (8.9 impact factor) on our favorite nutrient—phosphorus (P). She identified and quantified P minerals in legacy P soils (soils that have received way too much P over the years/decades) using a fantastic technique called XANES. She found out several cool minerals exist in both surface layer and soil sampling depth used for soil fertility analysis, in combination with calcium, iron, aluminum, and a few others (copper and manganese-based). She made anecdotal connections with water and chemical-extracted P pools. She suggested some of the minerals on the more P solubility side will control P release to crops and losses when/if soil solution P is depleted. Full reference: Lucas, E., L. Mosesso, T. Roswall, Y-Y. Yang, K. Scheckel, A. Shober, & G.S. Toor. 2022. X-ray absorption near edge structure spectroscopy reveals phosphate minerals at surface and agronomic sampling depths in agricultural Ultisols saturated with legacy phosphorus. Chemosphere, 308, 136288. https://doi.org/10.1016/j.chemosphere.2022.136288

    • New article outlining the results from a national soil fertility survey is published in a data paper. This dataset provides the current status of soil fertility testing across the US. It could be transformational in future collaborative efforts in the country to harmonize soil fertility recommendations across the state and regional boundaries. As part of the effort, information about soil test recommendations, fertilization philosophy, analytical methods, and the provenance of correlation and calibration data that support soil-test-based recommendations in US states were collected. Congrats to John Spargo from Penn State University and the FRST team led by Deanna Osmond from North Carolina State University. Here is the complete reference: Spargo, J. T., Lyons, S. E., Clark, J. D., Osmond, D. L., Parvej, R. Md., Pearce, A. W., Slaton, N. A., Saffire, D., Alford, S., Allen, T., Arnall, B., Buob, T., Camberato, J. J., Cardon, G., Culman, S, W., Davenport, J. R., Fernandez, F. G., Florence, R., Flynn, R., Franzen, D., Geisseler, D., Grove, J., Hardy, D., Heckman, J., Hopkins, B., Hoskins, B., Hue, N. V., Huluka, G., Jones, C., Jones, K., Kaiser, D. E., Kalmbach, B., Ketterings, Q. M., Laboski, C. A. M., Lessl, J., Lucas, E., Maguire, R., Mahler, R., Mallerino, A., Margenot, A., McGrath, J. M., Miller, R., Moore, A. D., Morris, T. F., Mylavarapu, R., Nathan, M., Nelson, N. O., Norton, J., Pena-Yewtukhiw, E., Pettinelli, D., Provin, T., Radin, A., Ross, D., Saunders, O., Self, J., Shober, A. L., Sonon, L., Sotomayor, D. R., Stammer, A., Steinke, K., Toor, G.S., Walworth, J., Wang, J. J., Wortmann, C., Zhang, H. (2022). A survey to evaluate the current status of land grant university and state department of agriculture soil fertility recommendations and analytical methods. Ag Data Commons. https://doi.org/10.15482/USDA.ADC/1526506

    • New article by the very talented former team member Yun-Ya Yang in a highly ranked and our favorite journal, Water Research (Impact Factor: >11), uses an advanced technique (FT-ICR-MS) to determine thousands of compounds in a water sample. In this paper, we focused on how the molecular composition of dissolved organic N (DON) and P (DOP) compounds differs as agricultural runoff waters traverse complicated flow paths in a watershed. We found that most DON and DOP compounds found in runoff and surface waters were present in less-bioavailable forms (like lignin), and many more-bioavailable compounds (like proteins) were degraded as runoff waters were transported from agricultural fields to downstream waters. To our knowledge (which the reviewers and journal editors concurred), this study is the first attempt to characterize both DON and DOP in runoff and surface waters and may lead to a better understanding of the critical role of organic N and P compounds in eutrophication, harmful algal blooms, and hypoxia! Full reference: Yang, Y., M. M. Tfaily, J.L. Wilmoth, & G.S. Toor. 2022. Molecular characterization of dissolved organic nitrogen and phosphorus in agricultural runoff and surface waters. Water Research, 118533. https://doi.org/10.1016/j.watres.2022.118533
       

    • New article on water desalination with authors from Greece, Saudi Arabia, Korea, Egypt, Turkey, India, and China. If you enjoy history, you would probably enjoy a deep dive into the history of desalination, beginning with Bronze Age (ca. 3200 BC) to the present. The article concludes with emerging trends in desalination, driven by technology and reduced costs of producing water (via desalination) for the growing human population. Some great pictures or paintings of artwork depicting cleaning/purifying water, are included. Here is the full reference: Angelakis, A.N., M. Valipour, K.-H. Choo, A.T. Ahmed, A. Baba, R. Kumar, G.S. Toor, & Z. Wang. 2021. Desalination: From Ancient to Present and Future. Water, 13, 2222. https://doi.org/10.3390/w13162222

    • New article by current MS Student Taylor Roswall in Water journal questions if our currently used methods to quantify soluble phosphorus in legacy soils saturated with historical manure applications are accurate? She discovered that the current methods underestimate soluble phosphorus pools in soils, which led to developing a revised and new method, and then the new method was used to investigate soluble P in phosphorus-rich soils. Here is the full reference: Roswall, T., E. Lucas, Y. Yang, C. Burgis, Isis SPC Scott, & G.S. Toor. 2021. Hotspots of legacy phosphorus in agricultural landscapes: Revisiting water-extractable phosphorus pools in soils. Water, 13, 1006. https://doi.org/10.3390/w13081006

    • New review article on soil health is published in the Advances in Agronomy journal. Toor, G.S., Y. Yang, S. Das, S. Dorsey, & G. Felton. 2021. Soil health in agricultural ecosystems: current status and future perspectives. Advances in Agronomy, 168, 157–201. https://doi.org/10.1016/bs.agron.2021.02.004

    • New article led by Dr. Shuiwang Duan in the Water journal investigated how, when, and why phosphate-mining and agriculture affect nutrient transport and water quality in a Florida watershed, where parts of the watershed are reclaimed and still actively mined. This was a challenging and fun paper to write from the data collected by Kamaljit Banger when he was an MS student with me at the University of Florida! Here is the full reference: Duan, S., K. Banger, & G.S. Toor. 2021. Evidence of phosphate mining and agriculture influence on concentrations, forms, and ratios of nitrogen and phosphorus in a Florida River. Water, 13, 1064. https://doi.org/10.3390/w13081064

    • New article led by Emileigh Lucas is accepted for publication in Agriculture, Ecosystems & Environment. Congratulations to Emileigh on her first first-author paper!  Lucas, E., G.S. Toor, & J. McGrath. 2021. Agronomic and environmental phosphorus decline in coastal plain soils after cessation of manure application. Agriculture, Ecosystems & Environment, 311, 107337. https://doi.org/10.​1016/​j.​agee.​2021.​107337  

    • New article with Professor Zhi Li's group at Northwest A&F University, Yangling, China, on nitrate transport in rivers across Loess Plateau region, published in the Science of the Total Environment journal. Ji, W., J. Xiao, G.S. Toor, & Z. Li. 2021. Nitrate-nitrogen transport in streamwater and groundwater in a loess covered region: Sources, drivers, and spatiotemporal variation. Science of the Total Environment, 761, 143278.https://doi.org/10.1016/j.scitotenv.2020.143278

    • New article by Dr. Yang on phosphorus transport from residential catchments to coastal waters is published in the Science of the Total Environment journal.  Yang, Y., S. Asal, & G.S. Toor. 2021. Residential catchments to coastal waters: Forms, fluxes, and mechanisms of phosphorus transport. Science of the Total Environment, 765, 142767. https://doi.org/10.1016/j.scitotenv.2020.142767 

    • New article on organic carbon in stormwater pond discharges, by former MS student Stefan Kalev and current group member Dr. Duan, is published in the Science of the Total Environment. Kalev, S., S. Duan, & G.S. Toor. 2021. Enriched dissolved organic carbon export from a residential stormwater pond. Science of the Total Environment, 751, 141773https://doi.org/10.1016/j.scitotenv.2020.141773

    • New article on the distribution of P pools in pastures grazed by cattle, with undergraduate students, is published in the Agrosystems, Geosciences & Environment journal. Toor, G.S., Y. Yang, M. Morris, P. Schwartz, Y. Darwish, G. Gaylord, & K. Webb. 2020. Phosphorus pools in soils under rotational and continuous grazed pastures. Agriculture, Ecosystems & Environment, 3: e20203. https://doi.org/10.1002/agg2.20103

    • New article on how to assess, quantify, and track soil organic carbon, by Dr. Yang and undergraduate students, is published in the Agronomy journal. Yang, Y, A. Goldsmith, I. Herold, S. Lecha, & G.S. Toor. 2020. Assessing soil organic carbon in soils to enhance and track future carbon storage. Agronomy10(8), 1139; https://doi.org/10.3390/agronomy10081139

    • New article on organic carbon forms in stormwater runoff, by a former MS student, is published in the Water journal. Kalev, S. & G.S. Toor. 2020. Concentrations and loads of dissolved and particulate organic carbon in urban stormwater runoff. Water12(4), 1031; https://doi.org/10.3390/w12041031

    • New article on nitrogen composition and source tracking in stormwater runoff, by a former PhD student, Dr. Jani, is published in the PLoS ONE journal. Jani, J., M. Lusk, Y. Yang, & G.S. Toor. 2020. Composition of nitrogen in urban residential stormwater runoff: Concentrations, loads, and source characterization of nitrate and organic nitrogen. PLoS ONE, 15(2): e0229715. https://doi.org/10.1371/journal.pone.0229715   

    • New article on nitrogen export from a stormwater pond, by former Ph.D. student, Dr. Jani, is published in the PLoS ONE journal. Jani, J., M. Lusk, Y.Y. Yang, & G.S. Toor. 2020. Wet season nitrogen export from a residential stormwater pond. PLoS ONE, 15(4): e0230908. https://doi.org/10.1371/journal.pone.0230908

    • New article on organic nitrogen in stormwater runoff, by former Ph.D. student, Dr. Lusk, is published in the Science of the Total Environment journal. Lusk, M, G.S. Toor, & P. Inglett. 2020. Organic nitrogen in residential stormwater runoff: Implications for stormwater management in urban watersheds. Science of the Total Environment, 707, 135962. https://doi.org/10.1016/j.scitotenv.2019.135962

    New Extension Factsheets

    • New Extension Factsheet on Soil Sampling! Soil samples provide information about the soil fertility status of a field, which is used to generate nutrient and lime recommendations and develop a farm's nutrient management plan. This factsheet outlines proper soil sampling techniques (how, when, why) to optimize crop production, minimize environmental degradation, and maximize farm profitability. Get your answers to these questions: how to take a representative soil sample, what depth to sample, should you take different samples from management zones within the same field, which time of the year should soil samples be taken? Kalmbach, B. & G.S. Toor. 2021. Soil Sampling for Optimizing Agricultural Production in Maryland. FS-1184. University of Maryland Extension, College Park, MD.

    • New Extension Factsheet on Converting Soil Test Values into Maryland Index Values: what would you do if you receive a soil test report from more than two labs for the same field, where different soil tests and units are reported? And those tests/numbers may not match with the extension recommendation for the state? To facilitate an easy transfer, conversion, and interpretation of numbers across tests and units, we use a unitless “Fertility Index Value or FIV” where soil testing units for nutrients are converted into a scale of 1 to 100. Then, these are classified into four categories of low (1-25), medium (26-50), optimum (51-100), and excessive (>100). We think this makes it easy for producers, consultants, regulators, and citizens to understand and compare soil test values across different labs and years. Toor, G.S., B. Kalmbach, P. Shipley, & D. Ruppert. 2021. Converting among Soil Test Analyses Frequently Used in Maryland. SFM-4, pp4. University of Maryland Extension, College Park, MD.

    • New Extension Factsheet on Nutrient Recommendations for Miscanthus. Kalmbach, B., G.S. Toor, & D. Ruppert. 2020. Soil Fertility Recommendations: Nitrogen, Phosphorus, and Potassium Requirements of Miscanthus. EB-443, pp 8. University of Maryland Extension, College Park, MD.

    BLOG

    Dr. Fajun Sun – Lab Manager

    April 2022. Hi! My name is Fajun Sun. I was born in China. I am the Lab Manager (Agricultural Technician Supervisor) in the Nutrient Management and Water Quality group. Before joining Dr. Toor’s group in October 2021, I received a Ph.D. in Geology from Florida State University. My dissertation research used geochemical tools (stable isotopes of carbon and oxygen) and models to provide insights into the paleoenvironment in Southeast China and Florida to better understand the effects of long-term climate change on terrestrial and coastal ecosystems. Understanding what happened in the past also helps to understand the causes and mechanisms of climate change and the effects on different ecosystems.

    The primary goal of my current work at UMD is to provide research support for members of the group, including helping students, postdocs, and faculty to analyze a variety of samples (water, soil, sediment) for nutrients, carbon, and various stable isotopes. In addition, I am responsible for supporting the management of various instruments in our lab, including Hach Lachat Quickchem Auto-Analyzer 8500, Shimadzu TOC-LCPN analyzer, and Thermo Delta V Isotope Ratio Mass Spectrometer (IRMS) equipped with EA and Gas Bench. My work supports several ongoing research projects to sustain agricultural production and improve water quality in Maryland and the Chesapeake Bay. One ongoing project that interests me is investigating phosphorus entering the Chesapeake Bay through biosolids generated by wastewater treatment plants; which has similarities to my Ph.D. project in the coastal regions in the Everglades National Park and the Gulf of Mexico. I am glad I can contribute to increasing understanding of environmental issues in agricultural and natural ecosystems.

    In a short period of six months here at UMD, I have learned a lot from everyone in the lab about using various instruments and ongoing research efforts to address pressing issues in the region. I hope to expand my technical and coordination skills to better support other researchers in the lab. In addition, as time permits, I am eager to start a new line of research inquiry in agricultural ecosystems.

    Since moving to Maryland, I am glad to have had a chance to explore various museums in Washington DC. I also enjoy cooking, hiking, and reading. I am pleased to be living and working in Maryland.

    Autumn McCarthy - Undergraduate Research Assistant

    March 2022. Hey y’all! My name is Autumn McCarthy. Currently, I am a Biochemistry junior at the University of Maryland. I joined Dr. Toor’s lab in February 2022. I am working with Emileigh Lucas as an undergraduate research assistant to assess the effect of agricultural management practices on organic carbon and phosphorus pools in soils. The findings of this research will provide Maryland farmers and consultants with the ability to measure and track soil organic carbon in various pools and address the issues of legacy phosphorus in Maryland soils. This project will expand my knowledge and skills and allow me to apply my background and capabilities in biochemistry which I will use in my future career. Working on this project brings back the joy I had learning about science for the first time as a child. Born and raised in Maryland, I have long understood the importance of protecting our environment and the Chesapeake Bay. Ultimately, I plan to build up my industry experience before attending graduate school for ecosystem health and natural resource management.

    Learning skills from each scientist in Dr. Toor’s lab, I hope to build on both my dry and wet lab skills, such as collecting and analyzing data using Lachat, Shimadzu TOC/L, Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), and Delta V Isotope Ratio Mass Spectrometer (IRMS). I had some experience in research before joining this project in the First-Year Innovative Research Experience-Found In Translation stream (FIRE-FIT). Through the guidance of my peer mentors, I gained molecular biology lab basic skills such as micro-pipetting, aseptic technique, molecular cloning, biosafety level 2 environment guidelines, and human cell culture and transfection. In addition, I have had the opportunity to demonstrate my organization and communication skills, assisting other projects and preparing samples for analysis.

    During my time outside of the project, I connect with my family and friends during my free time and develop my culinary and baking skills. Since moving into an apartment close to campus, I am able to try new and exciting recipes, which my roommate is happy to taste test with me. Also, I have a love for comedy. While I don’t have the time and resources to go to a comedy show every weekend, I enjoy finding new comics with the help of the internet.

    Quin Zabel - Undergraduate Research Assistant

    Feb 2022. Hello! My name is Quin Zabel, and I am a sophomore at the University of Maryland studying Chemistry and Environmental Science & Technology with a concentration in Ecosystem Health and a minor in Statistics. In Dr. Toor’s lab, I am working on a project, with Taylor Roswall, to investigate phosphorus entering the Chesapeake Bay through biosolids generated by wastewater treatment plants. This project is especially important due to how excess levels of phosphorus can spur eutrophication and contribute to spreading dead zones in the Chesapeake Bay. This project excites me due to the focus on how humans and the environment impact each other. In the future, I plan to go to graduate school for Environmental Chemistry or Toxicology and then work in Environmental Toxicology research. My overall goal is to complete research that influences environmental policy regarding human-ecosystem health system interactions, as I believe this is a huge source of environmental injustice in the world today. This environmental injustice largely presents as disproportionate adverse health effects relating to environmental degradation in socioeconomically disadvantaged communities, and I hope to study this field further and have a positive impact pushing toward environmental equity.

    During this research experience, I hope to expand my lab technical skills as well as see the research process in action. So far, I have had the opportunity to improve my self-organization skills and keep myself on a timeline even when setbacks come up in the lab. Additionally, I have enjoyed working hands-on with soil and developing systems to keep track of samples.

    Outside of the lab, I am the president of the UMD Ethics Bowl Team and enjoy studying environmental and bioethics. I also participate in research through the Gemstone Honors College and am on Team MARINE, studying microplastics. Finally, I really enjoy baking and have recently started a journey to perfect my chocolate chip cookie recipe!