Tillage and Cover Cropping Effects on Soil Physical Properties.

Management factors such as tillage have a significant influence on soil physical properties in medium and fine textured soils. Continuous cotton mono cropping under conventional tillage for several decades caused deterioration of soil physical properties in north Alabama. The objective of this study was to evaluate the long-term effects of conservation tillage, cover cropping and poultry litter on soil physical properties.  The soil physical properties evaluated included soil bulk density, saturated hydraulic conductivity, aggregate stability, particulate organic matter and soil moisture retention. The study was done on Decatur silt loam soil (clayey, kaolinitic thermic, Typic Paleudults) located in north Alabama.  Soil moisture in standing crop was collected once a week throughout the crop growing period. Bulk density was significantly higher in no-till (NT) (1.38 g cm^-3) compared to conventional till (CT) (1.26 g cm^-3) in the 0-5 cm soil depth. Saturated hydraulic conductivity in NT (5.57 cm hr^-1) was significantly higher compared to that in CT (2.45 cm hr^-1) at the 10-15 cm soil. Rye cover crop significantly improved the saturated hydraulic conductivity (5.6 cm hr^-1) at 10-15 cm soil compared to no cover cropping. There was no significant difference in soil moisture retention due to different tillage systems or different types of fertilization. We found no significant differences in particulate organic matter carbon in tillage or in different cropping systems, but the mean values in NT were 23 % and 22% higher compared to that in CT at 0-5 cm and 5 -15 cm soil depth respectively. Wet aggregate stability in macro-aggregate for all sizes tested was higher in NT compared to CT. We observed higher volumetric water content in NT compared to CT during the prolonged dry periods. Overall, our results showed that conservation tillage practices in addition to being economical, can improve soil physical properties and conditions.