2019 ASHS Annual Conference

Land management systems and alteration of the ecosystem can significantly affect soil quality indicators such as physical, chemical, and biological properties. In this study, changes in soil organic carbon (SOC), water stable aggregates (WSA), soil pH, soil moisture and particulate organic matter C (POM-C) were examined in two contrasting management practices (no till vs conventional tillage with and without cover crops). 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, Kentucky in 2018. Three types of cover crops being evaluated include wheat, cereal rye, oats and radish and a control with no cover crop. Findings show that SOC in the no till systems ranged from 2.4-2.9% while the conventional till systems ranged from 1.8-2.8%. The macroaggregates varied largely with the conventional till 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 no till cereal rye and conventional till system with no cover crop. Conventional till with no cover crop appears to have the highest ratio of macro- to microaggregates. The ratio of POM C to SOC remained mostly equal and steady across all samples, averaging 35% for all. The highest POM C was found in conventional till systems at average of 0.96% and the lowest was observed in cereal rye no till systems at both depth intervals with 0.64%. The soil pH ranged from 5.8-7.4 for the no till systems and 6.8-7.4 for the conventional till systems. No till systems with cereal rye had the lowest soil pH of 5.8 at depth 10-20 cm. There is no significant effect of tillage systems and cover crops on soil moisture content at air dry soils. The results of this study are important to predict the benefits of the combination effects of tillage and cover crops on soil quality changes.

Keywords: Cover crop, Macro-aggregates, No till, Organic carbon, Particulate organic matter