Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 22, 2000
Publication Date: N/A
Interpretive Summary: Both benefits, such as erosion control, and risks, such as cool and wet soils at planting time, are identified with variations in tillage and subsequent residue conditions. Additionally many short term effects may be overshadowed by long term changes in the soil system. The consequences of corn residue management or removal from cropland can only be evaluated under conditions when the changes in soil organic matter and its many associated physical and chemical properties are equilibrated. In our long term study with 6 variations in tillage and residue conditions including residue removal under which both grain and stover yields have been measured it appears that water conservation, which can be substantial in those years when growing season precipitation is limited, is a major and economically important benefit through higher grain yields. Residue removal must yield sufficient benefit to the farmer to counterbalance the reduction in income due to lost yields. This research will allow the farmer to make an informed choice on corn residue management.
Technical Abstract: The effect of tillage and residue management on corn (Zea mays L.) grain and stover yields was studied for 13 seasons in east central Minnesota. Three primary tillage methods [no-till (NT), fall chisel plow (CH), fall moldboard plow (MB)] and two residue management schemes residue removal versus residue returned were combined in a factorial design. No significant teffects on grain yield were seen due to tillage in 9 out of 13 years. NT produced yields lower than CH and MB in years 6 and 7, and lower than MB in year 8, indicating a gradual decrease in yield over time with continuous NT. There were differences due to residue management in at least 8 out of 13 years. Residue returned contributed to greater yields in intermediate level dry years such as year 3 and year 6 which had cumulative growing season precipitation 20 and 30 percent below the nine year average, respectively. In excessively dry or normal years residues provided little yield difference between treatments. The most pronounced effects of residues were on CH treatments with significantly greater yields in 8 out of 13 years. The ratio of grain to total dry matter yield averaged 0.56 and did not vary with time or between treatments.