Soil Health Assessment after 25 Years of Tillage and Manure Management.

Nutrient management systems differ between organic and conventional agriculture, and thus leave a different footprint on soil quality.  Conventional management uses mineral sources of fertilizer, and no-tillage systems. Organic agriculture nutrient inputs come from biomass sources such as manure, cover crops and residues. Additionally, tillage is often used as a method of pest control. These management practices have different advantages and disadvantages for soil health, as well as carbon sequestration and crop yield.

            The purpose of this study was to compare the differences in soil quality under chisel disk tillage vs no-tillage, and in different fertilization systems: 168-kg N ha-1as ammonium nitrate, 168-kg N ha-1as cattle manure, and a non-fertilized control. Soil samples were taken in prior to planting, to a depth of 30 cm. Physical, chemical and microbial factors will be measured by the following analyses:  Water Stable Aggregate Distribution, Bulk Density, Extractable Nitrogen, Water Soluble Carbon and Mineralizable Carbon, and PLFA microbial community. It is expected that no-tillage systems will have better quality soil than tilled systems. This includes higher organic matter content, more stable aggregation, and more diverse microbial populations. It is also expected that manure application will increase soil organic matter, and improve soil aggregation. However, the manure application may reduce AM fungi colonization due to high phosphorous application.