Aggregation and Soil Organic Carbon Pools Following Tillage-Cover Crop Practices.

Management practices in cultivated cropland generally affect soil quality, thus eventually influencing the crop yield. For sustainability, it is important to improve soils and reduce erosion by using cover crops in the off season with normal crop rotational practices. The objective of this study was to evaluate the changes in soil properties due to tillage systems and the use of cover crops in western Kentucky. Soil samples from no tillage (NT) and conventional tillage (CT) plots were collected from the depth of 10 cm and 20 cm in Calloway County in September 2018. The cover crops being assessed include wheat, cereal rye, oats and radish and a control with no cover crop. All samples were taken in standing corn fields. The samples were analyzed for soil organic C (SOC), soil water content, particular organic matter-C (POM-C), and macroaggregates. Soil organic C in the NT systems ranged from 2.4-2.9% while the CT systems ranged from 1.8-2.8%. The ratio of C-macroaggregates-to-soil organic carbon (SOC) was highest onaverage in the 0-10 cm depth, and highest overall in the NT oats and rye. The macroaggregates varied largely with the CT system with no cover crop containing the most in both depths. The ratio of macro-to-microaggregates in both tillage systems was fairly equal with exceptions to NT cereal rye and CT with no cover crop. CT with no cover crop appears to have the highest ratio of Ma/Mi. The highest POM C was found in CT systems at average of 0.96% and the lowest was observed in cereal rye NT systems at both depth intervals with 0.64%. The results of this study would be beneficial to producers with regards to soil conservation and yield sustainability.