Conservation tillage effects on soil physical and chemical properties in rice production in the Arkansas Delta

Cultivation of rice has been ongoing in the state of Arkansas for nearly a century. Arkansas leads the nation generating 46.5% of total U.S. rice production. Conventional-tillage (CN) practices used for rice production in the Mississippi River Delta are very intensive. It is believed that over one-hundred years of CN, soil physical and chemical properties may have been altered negatively. Conservation-tillage or no-till (NT) in rice production is a technique rarely used, but is being explored as an alternative to CN. The objectives of this study were to evaluate the effects of tillage and crop rotation on soil physical and chemical properties (i.e., soil aggregate stability, soil penetration resistance and moisture, and aggregate associated C and N). Soil samples for this study were obtained to compare cropping rotation and tillage treatments. Results indicated increasing the frequency of large residue producing crops (i.e. rice, wheat, corn) in a rotation resulted in increased water-stable aggregates (WSA) and increased C and N concentration and contribution of soil aggregates. The use of NT also increased WSA especially when grown in rotations containing crops that return more biomass to the soil, as well as lowered soil penetration resistance values at soil depths of 10- to 40-cm. Continued research may lead to increased awareness and development of more sustainable agricultural practices that can lead to a less degraded soil for future productivity.