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Dr. Ray Weil's Research Group: Current Graduate and Undergraduate Students

GUIHUA CHEN: Alleviation of soil compaction by Brassica cover crops
LawleySoil compaction is a worldwide problem in modern agriculture which restricts plant root growth, water and nutrient uptake, and results in yield reduction. My experiments demonstrated that Brassica cover crop (forage radish or rapeseed) roots are more capable to penetrate compacted soils than rye roots. It was further proved that corn /soybean benefits from Brassica cover crop(s) by growing more roots into and below compacted soil layer, taking up more subsoil water and achieving greater yields.

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YONNE LAWLEY: Using forage radish winter cover crops to control weeds in the Mid-Atlantic Region

YonneMy project characterized weed suppression during and after forage radish growth to better understand how this new cover crop may be used in grain or vegetable cropping systems of the Mid-Atlantic region. In a series of field, greenhouse and growth chamber experiments, I showed that when planted in August, forage radish controlled weeds in the fall, winter, and early spring. This cover crop can replace a pre plant herbicide application, but cannot replace in-growing season weed control. The forage radish suppressed or delayed emergence of horseweed (Conyza canadensis) and may provide a new tool to control herbicide resistant biotypes. The low-residue weed-free seedbed following forage radish cover allows early planting and provides an exciting opportunity for farmers looking to develop organic no-till systems.

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charlieCHARLIE WHITE: Forage radish and winter rye cover crop effects on mycorrhizal fungi and phosphorus availability
Arbuscular mycorrhizal fungi are beneficial soil organisms that aid plant roots in the acquisition of phosphorus, sequester carbon in soil, and improve soil aggregate stability.  Forage radish, like other members of the Brassica family, does not host arbuscular mycorrhizal fungi and releases anti-fungal compounds during its decomposition. A negative effect of forage radish cover crops on mycorrhizal fungi could influence subsequent soil fertility and soil quality. In six site years of experiments, mycorrhizal root colonization of subsequent corn at an early growth stage was the same whether forage radish or no cover crop at all had been grown; this colonization was higher following winter rye, a cover crop that hosts mycorrhizal fungi. Early differences in colonization did not translate into corn grain yield differences.

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WES BICKFORD: Assists Drs. Weil and Needelman in their project on marsh burning.

WesPrescribed burning can promote desirable vegetation and wildlife habitat. Burning also consumes organic material, removing the marsh vegetation canopy and depositing nutrient rich ash.  A field study at Blackwater National Wildlife Refuge in Cambridge, MD will study the effects of simulated canopy removal and ash deposition on vegetation responses and marsh accretion under annually burned and unburned conditions.

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MargaretMARGARET GUTHRIE: tree nursery use of cover crops to enhance soil fertility; sustainability of tree harvesting practices; use of harvested dried forage radish tissue to combat fungal plant pathogens; effect of forage radish on soil microbial communities and disease resistance of soils.

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jonJONATHAN BERLIN: Assisting with research on Soil Erosion and Runoff Losses as Affected by Cover Crops. I will collect samples in the field and then help analyze them for runoff volume, suspended solids and phosphorus.

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NancyNANCY NOBES: Assist in research how later planting dates influence the ability of forage radish cover to capture nitrogen and prevent nitrate leaching. I also am an undergraduate TA for a lab section in Dr. Weil’s introductory Soils course.    

 

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amandaAMANDA GARZIO: Assisting with research on: Soil Erosion and Runoff Losses as Affected by Cover Crops. I helped install 24 erosion weirs in the fields of two commercial fruit & vegetable farmers. I collect runoff samples and analyzed them for sediment and runoff volume.   

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HannaHANNA POFFENBARGER: Assisting Drs. Needelman and Weil in  their research on effects of prescribed burning in salt marshes, including analysis of the data in the literature on sulfate inhibition of methanogenesis in marsh soils. She also is an undergraduate TA for a lab section in Dr. Weil's introductory Soils course. 

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SarahSARAH KNEBEL: Assisting with research on soil nitrogen dynamics and helping to developing a new approach to measuring soil nitrogen dynamics in real time by monitoring changes in electrical conductivity of the soil solution. Conducting laboratory analyses to correlate nitrate-N concentration with EC in soils experiencing he decay of cover crop residues.

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XiaojieXIAOJIE ZHANG: Assisting with research on soil compaction crop root growth. She makes measurements of root length and surface area by means of isolating roots from soil core samples, making digital images and determining root length by image analysis. Verifying the image analysis results using known lengths. Xiajie has also assisted with installing erosion – runoff measurement weirs.    

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Last updated: 03/10/2009