Corn and Soybean Yields As Affected By Residue Management and Tillage in the Mississippi Delta.

Mississippi Delta producers are continually looking for ways to increase profitability through increased yields or decreased cost per production unit. The primary costs of production include seed, fertilizer, and pesticides along with primary tillage and field preparations. Since the advent of mechanized agriculture, producers have moved toward less primary tillage and more chemical control of weeds and other pests. In the Mid-south, 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 the field also leads the higher production costs. Multi-year field studies were established in two regions of Mississippi to examine the interaction of residue management and tillage for corn and soybean grown in a 1:1 (corn:soybean) rotation. Tillage systems 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]. Also included in the objectives was a burn/no burn option for corn residue management, a common practice for many growers. The research locations were established as a split plot with the whole plot as a) burn corn residue and b) no burn of corn residue. The sub plots were the tillage treatments already outlined above. The two locations for the studies were 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. 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. Soybean yields have been more stable than corn yields in the Delta.