Tillage and Residue Management in the Mississippi Delta - Corn and Soybean Yields.

Mississippi Delta producers continue to search for avenues to increase profitability either through higher yields or lower cost per production unit. Production costs include seed, fertilizer, and pesticides along with tillage and land preparations. With mechanized agriculture, growers in the Mid-South USA have moved toward a decrease in primary tillage and an increase in chemical control of weeds and other pests. Soils tend to be less than 1.5% organic matter and often have traffic pans that impede root penetration and reduce nutrient and water uptake. Multiple trips across fields lead to higher production costs. Multi-year field studies were established in two Mississippi regions to examine the interaction of residue management and tillage for corn and soybean grown in a 1:1 (soybean:corn) rotation. The tillage systems under investigation included: 1) a minimum tillage system [re-shape beds as needed]; 2) bed and roll; 3) subsoil, bed, and roll [one-pass]; and 4) conventional [disk (2X) + one-pass]. The studies also included a burn/no burn option for corn residue management, a common practice for many growers. Studies were located in the Mississippi Delta (irrigated) and in the North Mississippi Hill area (rain-fed). All cultural practices were consistent for the location but varied by location. The center rows of each 4-row plot were harvested with samples collected for harvest moisture, test weight, and Seed Index (100-seed weight). Yield variations have occurred across locations with the sandier Delta location requiring more bed-shaping as a result of winter precipitation and bed degradation. In the Delta, corn yields were significantly affected by tillage five of six years with lower yields associated with the reduced tillage system except in 2012. Soybean yield was only significantly affect in one of six years. While reduced tillage remains the goal, reshaping beds in the Delta is needed to continued drainage.