Dr. Alwyn Williams: On Sustainable Agriculture and Building Soil Health

On Thursday, 16 February, Dr. Alwyn Williams presented his research in soil functional zone management (SFZM) to the Department of Plant Science and Landscape Architecture. Dr. Williams is world traveled and has lived in many different countries. He is now an Assistant Research Scientist at the University of Maryland. Soil functional zone management is an agricultural land management technique that integrates practices from both conventional and no-till farming systems to maintain the intensive agricultural productivity of conventional management while also preserving ecosystem services through restricted tillage. Dr. Williams introduced his research by putting it in the context of boosting crop yields. This will be necessary to feed the growing global population in the face of climate change. Soil functional zone management harnesses soil ecosystem benefits by creating spatial heterogeneity in the soil. He spoke about his research on ridge tillage, a form of SFZM, in Illinois, Michigan, Minnesota, and Pennsylvania. Ridge tillage can enhance the growth of microbial soil communities, build the soil organic carbon pool, mobilize nutrients during crucial plant growth periods, encourage weed suppression, and increase soil aggregation and water holding capacity. Furthermore, SFZM can lengthen the growing season significantly by stimulating soil warming and drying.

After two years of research, Dr. Williams has already found positive effects of SZFM. In his study, ridge tillage increased soil organic carbon and mobilized nitrogen (N) with no significant loss of corn yield (Williams et al., 2017). Specifically, he found that plant-available N in ridged rows was greater than in inter-rows. This result was the opposite of what he found in conventional tillage systems. Therefore, SZFM may enhance plant nutrient availability when the crop needs it most. Ecological soil building processes, particularly soil organic carbon accumulation, often take many years to significantly enhance soil health. It will be interesting to see his results after another few years! He noted in his presentation that this research was conducted in corn and soy fields and recommends more research on SZFM in other cropping systems. Dr. Williams’ ecological approach to farm management is exciting and can help us build a more holistic approach to addressing tough questions about the global food supply.

• Dani Weissman

References:

Williams, A., Davis, A. S., Jilling, A., Grandy, A. S., Koide, R. T., Mortensen, D. A., … Jordan, N. R. (2017). Reconciling opposing soil processes in row-crop agroecosystems via soil functional zone management. Agriculture, Ecosystems and Environment, 236, 99–107. https://doi.org/10.1016/j.agee.2016.11.012

Williams, A., Kane, D. A., Ewing, P. M., Atwood, L. W., Jilling, A., Li, M., … Jordan, N. R. (2016). Soil functional zone management: a vehicle for enhancing production and soil ecosystem services in row-crop agroecosystems. Frontiers in Plant Science, 7(February), 1–15. https://doi.org/10.3389/fpls.2016.00065