Submitted to: Zero Tillage Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 27, 2006
Publication Date: February 9, 2006
Citation: Nichols, K.A. 2006. Making soil biology work for you. IN: Andy Berntson (ed.) 28th Annual Zero Tillage & Winter Wheat Workshop. 9-10 Feb. Manitoba-North Dakota Zero-Tillage Farmers Association Conference Proceedings. Interpretive Summary: Increases in global population and energy costs are major challenges facing U.S. agriculture. Mismanagement of the soil resource while attempting to increase productivity to meet these challenges will result in further declines in soil quality. Soils provide a home to billions of soil organisms. These organisms play a vital role in producing high quality soils to support plant growth. Arbuscular mycorrhizal (AM) fungi are a keystone group in soil resource management. Fungal hyphae act as a nutrient conduit from abundant areas in soil to depletion zones around roots. In return, the fungi receive carbon directly from the plant to continue their growth. The efficiency of pick-up and delivery system is maximized by minimizing the amount of carbon and energy required to make and maintain this system. Threadlike hyphae (i.e. the fungal body) will narrow and branch maximizing the surface area exposed to the soil at the nutrient ‘pick-up’ end. Hyphae penetrate plant root cells to drop the nutrients off right inside the ‘front door’ using finely branched structures called arbuscules. Glomalin is a sugar protein produced by AM fungi which is speculated to protect conduit hyphae from nutrient loss and microbial attack. In addition to protecting hyphae, glomalin also has a sticky, sugar component that glues aggregates together and a water-repelling component that forms a protective lattice around aggregates to keep the water stable. Soil aggregates are pellets of various shapes and sizes that reduce compaction in soil, increase water infiltration and aeration, improve nutrient cycling, create homes for soil organisms, and reduce susceptibility to wind and water erosion. Effective management of soil organisms, especially mycorrhizal fungi, will maintain the soil resource and provide a consistent supply of plant available nutrients to meet the demands of food, feed and fiber production for a growing global population. These management systems include reduced tillage, continuous plant cover, reduced synthetic fertilizer inputs, diversified cropping systems, and usage of AM host crops.
Technical Abstract: Effective soil resource management will help U.S. agriculture meet the challenges stemming from increases in global population and energy costs. Soils are defined by the life within them which allows them to support plant growth. Arbuscular mycorrhizal (AM) fungi are a keystone group of soil organisms. The fungal hyphae transport nutrients from the soil to plant roots. Because hyphae form finely branched threads, more of their surface area is exposed to the soil to maximize the amount of nutrients attained. These nutrients are delivered to the plant inside plant root cells via finely branched arbuscules which minimize loss and maximize the amount delivered. Glomalin is a glycoprotein produced by AM fungi that protects the fungal hyphae and assists in the formation and stabilization of soil aggregates. Management systems including reduced tillage, continuous plant cover, reduced synthetic fertilizer inputs, diversified cropping systems, and usage of AM host crops will support soil life and improve soil quality.