Soil Quality Lab

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.

The lab probes fundamental relationships among soil organic matter fractions and soil ecological functions and is contributing to our understanding of the active fraction of soil organic matter. The lab is known for developing a practical test for easily oxidized, microbially active carbon as part of soil organic matter. Our lab’s permanganate oxidizable carbon test (termed POXC in the scientific literature) is now used by researchers worldwide as a leading indication of soil health and carbon dynamics in a wide range of soils.

The lab’s nutrient cycling work is focused efficient use of N, P and S in various agroecosystems, including intensively grazed pastures, tropical smallholder farms, and high yield conservation grain production systems. Our work on sulfur fertility has shown that optimizing the supply of this of-neglected essential nutrient can dramatically improve the nutritional quality of legume proteins as well as yields. Our work on nitrogen has revealed large pools of mineral N that remain deep in the soil after summer crop growth. Stable isotope tracer work has shown that this nitrogen can be captured by deep rooted vegetation.

Additionally, the lab is investigating multiple soil, economic and environmental benefits derived from innovative cover crop systems. This work introduced the daikon type radish as a cover crop to North American farmers, including the “Tillage Radish” brand developed by Steve Groff, a collaborating farmer-entrepreneur in Pennsylvania. The lab’s cover crop work has had a wide impact, demonstrating, among other benefits, the compaction-alleviation capacity of the radish and other brassica cover crop roots. Our recent work has demonstrated the importance of establishing mixed-species cover crop early in the late summer or fall, generally even before harvest of summer cash crops. Similarly, the  lab is researching how to achieve the benefits of allowing cover crops to grow longer in spring, sometimes even beyond the planting of summer cash crops (a practice known as “planting green”).

The Soil Quality lab is fully equipped for a wide range of soil and plant analyses, as well as field studies such as those requiring deep soil cores, continuous soil monitoring, or root images via mini-rhizotron. The lab is doing pioneering research on the use of portable X-ray fluorescence to analyze plant tissue for nutrient element content. The lab has also developed field-ready on-the-spot analyses for a number of important soil quality parameters. These have been incorporated into a system of soil analysis called SoilDoc in collaboration with the AgCenter at Columbia University’s Earth Institute where Ray was a senior adjunct research scientist, and now with the University of Florida. This system has been deployed in many tropical countries that lack a well-developed soil testing lab infrastructure.

Dr. Weil
Dr. Ray Weil
rweil@umd.edu​​​​​