Crop Residue Management and Tillage Systems' Impact on Yield and Soil Quality.

A six-year (2012-2017) study evaluated crop residue management and tillage systems’ impact on soil quality, and yield in a soybean/corn rotation on a loam soil. The crop residue management systems were burning and not burning corn crop residue. Fall tillage systems: 1) Reduced Till (reshaped old beds when bed heights were less than 3 or 4 inches); 2) Bed-roller; 3) in-row subsoil-bed-roller (TerraTill^®, one-pass implement, Bigham Ag, Lubbock, TX); and 4) Disk (2x) + TerraTill. Burning corn crop residue resulted in lower spring bed heights with only less ground cover in 2012 and 2014; and lower soybean and corn yield in 2013 and 2016, respectively, with no negative effect on soil quality. With no tillage by year interaction, the six-year average 74 bu/acre TerraTill yield was greater than Reduced Till, Bed-roller and Disk (2x) + TerraTill. The six-year average 225 bu/acre TerraTill yield was greater than the Disk (2x) + TerraTill, Bed-roller and Reduced Till.

Soil quality factors (aggregate stability, soil microbial biomass and soil respiration) were greater for Reduced Till than Disk (2x) + TerraTill, and Bed-roller. Most often TerraTill soil quality factors were similar to Reduced Till and greater than Disk (2x) + TerraTill and Bed-roller. In 2017 Reduced Till, Bed-roller and TerraTill sites had very similar soil organic matter (1.39%) but were significantly greater than the 1.27% for Disk (2x) + TerraTill. Disk operations for both corn and soybeans did not enhance yield and had a negative impact on soil quality. Disk (2x) + TerraTill soil environment also had more Proteobacteria (destroy soil organic matter) than the other tillage systems. These results indicated an in-row-subsoil-bed-roller (one-pass) system can improve yield with a positive effect on soil quality.