DEVELOP AND IMPROVE STRATEGIES FOR MANAGEMENT OF IRRIGATED AGRICULTURAL CROPS AND SOILS
Location: Northwest Irrigation and Soils Research
Title: Nitrogen Mineralization Response to Tillage Practices on Low and High Nitrogen Soils
Submitted to: Proceedings of the Idaho Nutrient Management Conference
Publication Type: Proceedings
Publication Acceptance Date: March 9, 2010
Publication Date: March 9, 2010
Citation: Moore, A., Tarkalson, D.D. 2010. Nitrogen Mineralization Response to Tillage Practices on Low and High Nitrogen Soils. In: Proceedings of the Idaho Nutrient Management Conference, March 9, 2010, Shoshone, Idaho. p. 65-68.
In strip tillage, crop residue is left on soil surface, decreasing the contact between soil and the residue, and therefore reducing decomposition rates compared to conventional tillage methods. Decomposition rates directly affect carbon and nitrogen ratios, which can affect nitrogen mineralization rates. The objective of this research is to determine the effect of tillage method and nitrogen rate on nitrogen available to sugar beets planted after a cereal crop. This two-year field study conducted in Kimberly, Idaho, consisted of three tillage methods (moldboard plow, chisel plow, and strip tillage), two tillage timings (fall and spring), and four fertilizer N rates plus a control. Soils from each plot were sampled shortly after nitrogen fertilization and incubated at average seasonal temperatures for Kimberly, Idaho to monitor nitrogen mineralization patterns. In 2008, we found that at N fertilizer rates of 0, 50, and 100 lbs N per acre, intensive tillage (moldboard plow and chisel plow) in the spring had the greatest potential for decreasing plant available nitrogen and increasing soil carbon, while intensive tillage in the fall slightly increased plant available nitrogen. No tillage method or tillage timing effects were detected in 2009, likely due to unexpectedly high residual nitrogen concentrations in the soil. It appears that tillage method and timing are more likely to impact nitrogen mineralization in growth limiting (low N) environments.