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Dr. Raymond Weil



Professional Activities  |  Soil Quality Lab  |  International Activities  |  Select Publications


Professor Ray R. Weil is an internationally recognized expert on soil science, nutrient cycling, soil organic matter and cover crop systems for soil health and water quality. His methods for soil microbial biomass and active carbon (POXC) are adopted by USDA/NRCS and researchers worldwide. His research on multi-purpose cover crops and ecological approaches to soil management is used by landscape managers and farms, large and small. He has advised on food security and soil management in Africa and other developing regions. He teaches undergraduate and graduate-level courses in soil science, soil fertility and sustainable agriculture. In 2022 he was awarded the FoodShot Global Groundbreaker Prize for his work on soil sulfur and food protein quality. His textbook, The Nature and Properties of Soils, is the most widely used soils textbook in the US and around the world.

Environmental Science & Technology 0115 HJ Patterson Hall 4065 Campus Dr. College Park, Maryland 20742

Soil Quality Lab webpage on ENST Site

Dr. Ray Weil on Google Scholar

For Package Delivery Dock H, AnSc-AgEng Bldg. #142 8127 Reagents Drive College Park, Maryland 20742


  • Soil Science
  • Agronomy
  • Soil Health
  • sustainable agriculture
  • International Development
  • Cover Crops
  • Soil Fertility
  • soil organic matter
  • soil carbon
  • soil compaction
  • Soil Conservation
  • Nitrogen cycling
  • Phosphorus
  • Sulfur
  • Organic transition

Professional Activities


I am dedicated to researching and promoting the adoption of soil health practices, especially more sustainable agricultural systems in both industrial and developing countries. My research focuses on soil management for enhanced soil health and nutrient cycling for productivity, water quality, and sustainability. I have also been a dedicated educator at all levels for more than 40 years, having taught over 6,500 undergraduate and graduate students in his university courses, addressed over 5000 farmers at meetings and field days, and helped train hundreds of researchers and managers in numerous companies and organizations. I have been privileged to be the major advisor for over 42 MS and Ph.D. students. The undergraduate and graduate courses I have developed and taught include two introductory courses, Soil and Environmental Quality (ENST105) and Fundamentals of Soil Science(ENST200), and three upper-level courses: Principles of Soil Fertility(ENST411), Issues in Sustainable Agriculture(ENST441), and Advanced Soil-Plant Relationships(ENST611). I aim to engage students with enthusiasm for soil science and open their eyes to the many ecological roles played by soils, but also maintain high standards and rigorous grading.

My program at the University of Maryland attempts to integrate all three legs of the Land Grant University Mission, teaching, extension, and research, in a manner that benefits all three. My teaching philosophy is summarized by three “I”s: inspire, integrate, and inform. Students in the classroom are energized by hearing first-hand accounts of soils problems and investigations and benefit by learning science from an active scientist. At the same time, the classroom discussions of cutting-edge concepts often inspire my graduate students and me to work on new research ideas.  I view my extension activities provide a two-way flow of ideas to and from regional and global farmers and other soil management practitioners.  The synergism between teaching and research and my ecological approach to soil science find their ultimate expression in my work as author of the most widely used textbook in soil science, The Nature and Properties of Soils

My research program combines three interrelated areas: 1) Organic Matter Management for Soil Health; 2) Sustainable Farming Systems, and 3) Soil Management for Improved Nutrient Cycling and Water Quality.  Much of my current work revolves around enhanced management of cover crops as major tools that impact all three of these research areas. Whenever I have the opportunity, I like to work with farmers in developing countries, especially those in Africa, by diagnosing and finding solutions to agricultural problems in the field while collaborating on integrated agricultural development and soils-related issues.

Research Topic Areas

  • Multi-Purpose Cover Crops to Enhance The Environment and Farm Profitability
  • Soil Health & Quality Management for Sustainable Agriculture
  • Profitable and Soil-Health-Building Strategies for Transitioning to Organic Grains
  • Active Organic Matter Test to Help Assess Soil Health
  • Environmental Impacts of Management Intensive Grazing Based Dairy Farms
  • Sulfur Fertility to Enhance Yields and Protein Quality of Grain Legumes
  • Soil and Nutrient Management
  • Regenerative African Small Holder Farming

Soil Quality Lab


The Soil Quality lab under the leadership of Professor Ray Weil studies physical, chemical and biological aspects of Soil Quality and Health as related to Management of Soil Organic Carbon, Nutrient Cycling and Water Quality, and Sustainable Farming Systems.


Learn More


The Soil Quality Lab has post-doc researchers, graduate students, and undergrad research assistants. See our current researchers and a list of our lab alumni:


Meet Our Researchers

Research Projects

Areas of research focus at the Soil Quality Lab: Soil Science, Soil Health, Nutrient Cycling, Sustainable Agriculture, Systems Water Quality.


Current and Ongoing Research

Plant Nutrient Deficiencies

Search through a visual reference guide that can help identify nutrient deficiencies in your soil that can affect your plants.


Plant Nutrient Deficiencies

Cover Crop Innovation Center

The Cover Crop Innovation Center grows and tests cover crops with the goal of improving soil health and reducing soil loss through the use of cover crops and best agricultural practices. 


Learn More 

International Activities


Soil work in AfricaSoil Conservation in Yinchuan, China

In 2014 and 2017 Weil visited Ningxia in western China to collaborate with research from Cornell University, the Key Laboratory of Forest Biotechnology and Ningxia University on technologies for soil, water, and biodiversity conservation in this desertified region.

Uganda Oil seed production and soil health

In 2022 Dr. Weil worked in several remote villages in northern Uganda to teach ecological, soil-centric farming to small holder farmers as part of USDAID and Catholic Relief Services farmer - to - Farmer Program.


SoilDoc Development

Soil work in AfricaSoilDoc Development and Deployment for African Smallholder Farmers


Soil work in LiberiaTraining the Trainers in Liberia

Weil worked in several counties of Liberia to assist local NGOs in diagnosing and solving soil fertility problems that plagues smallholder vegetable farmers.

Millennium Villages

Soil work as part of Millennium Villages ProjectMillennium Villages Project

From June 2009 to January 2010, Weil served as Senior Research Fellow at Earth Institute Tropical Agriculture Program at Columbia University, New York in which capacity he advised the Millennium Villages Project in on soil and crop related issue in Tanzania, Kenya, Ethiopia, Malawi, Uganda, and Senegal. In each of these countries Weil worked to solve agriculturally related problems in village clusters with up to 30,000 residents. Working directly with villagers as well as with the staff of this integrated development project, Weil performed field diagnosis and problem solving on a wide range of issues including compost production, human waste recycling, fertilizer recommendations, nutrients from indigenous sources, irrigation, soil conservation, cropping systems and rotations, agroforestry, soil testing, soil mapping, materials transport and agronomic crop management.


Soil work in MexicoTarahumara Indigenous Peoples in Mexico

During July 2005 and again in August-September 2009, Weil served as advisor on soil and water issues in rural development for the Tarahumara indigenous peoples in the Sierra Madre Mountains in Mexico. I advised the Government of Chihuahua State, Mexico, Coordinacion por las Tarahumara on compost production and use and on the production of seed for special indigenous “blue” corn that the local communities were producing and processing into premium food products such a pinole, chips and corn meal. Weil also worked closely with field staff of the Laguna Foundation in several isolated Tarahumara communities. This work including problem solving, advising and training on soil conservation, vegetable gardening, irrigation, compost and fertilizer use and other aspects of soil fertility in the Sierra.


Soil work as part of Food SecurityInternational Symposium on Climate Change and Food Security

In August 2008, Weil participated in research planning meetings, presented a lecture at University of Dhaka and served as session chair and a keynote speaker in the International Symposium on Climate Change and Food Security in South Asia, Dhaka, Bangladesh.


Black Desert Project

In January 2007, I made a study visit with colleagues from Cairo University to research sites in the Black Desert.


Soil work in Central AfricaRelationships Between Soil Health and Human Health in Central Africa

In January 2006 and July/August 2007, I conducted field research dealing with the relationships between soil health and human health in southern Chad, central Africa. The work was funded by a National Science Foundation grant in collaboration with The School of Public Health at Johns Hopkins University. Recent discovery of oil fields and development of pipelines in Chad had lead to changes in land use and land availability, influencing the pattern of local agricultural rotations with natural fallow. The visit in 2007 was devoted to training Chadian staff and collecting soil quality baseline data in villagers fields.


Soil work in EthiopiaEthiopian Agriculture Research Organization

During July–December, 2001, I served as advisor to the Ethiopian Agriculture Research Organization in the area of Soil and Water Research under a World Bank Agricultural Research and Training Project. In this capacity I worked at both the headquarters and at various research locations around the country to train and assist Ethiopian researchers in advancing agricultural and soil investigations.


Soil work in BrazilSoil Quality Research in Brazil

In July 2000 I collaborated in soil quality research in southern Brazil and presented seminars at the Federal University of Pelotas and the Federal University of Santa Maria.


Hands-On Sustainable Development in Honduras

In 1998-2000 I organized and led a soil quality research porject and a January “wintermester” Study Abroad course entitled “Hands-On Sustainable Development in Honduras” in collaboration with El Zamorano University about 50 km from Tegucigalpa, Honduras. Eleven University of Maryland students paired up with El Zamorano counterparts to work on research projects in the field.