|Wortmann, Charles - UNIV OF NE/LINCOLN|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 5, 2003
Publication Date: March 1, 2004
Citation: Wilhelm, W.W., Wortmann, C.S. 2004. Tillage and rotation interactions for corn and soybean grain yield as affected by precipitation and air temperature. Agronomy Journal 96:425-432. Interpretive Summary: Reduced or no tillage and crop rotation are common practices for corn and soybean production in the Midwest. Benefits from use of no-till differ with location (north or south in the Corn Belt) and crop rotation. No tillage tends to be of greater benefit in the southern part of the Corn Belt. Southern Nebraska is located in the transitional region for positive or negative impact of no tillage. The interactions of tillage system and crop rotation with seasonal weather conditions make identification of the appropriate combination of tillage and crop sequence difficult. This experiment was conducted to quantify the influence of weather on the effects of primary tillage (plow, disk, chisel, sub-soil, ridge-till, and no-till) and rotated and continuous corn or soybean in southeastern Nebraska. Data from a 16-year rain fed study were used for the analysis. Corn and soybean yields were less with higher summer temperature. Soybean, but surprisingly not corn, yield increased with summer rainfall. Corn yields were less with no-till than with plow. Yields of corn with all other tillage practices were similar over the 16 years of study. The tillage by year interaction was significant for yield of both crops; the yield advantage for plow was less during seasons with warmer springs. Yield of corn under all tillage systems showed a similar response to an environmental index that characterized the production potential for each year of the study (the index was the yearly mean yield for all treatments). Yield of corn grown in the no-till and plow treatments, which differed from the other treatments, also deviated most from the average response to the environmental index. The deviation was due mainly to differing responses to spring temperature. Yield was greater with crops grown in rotation than with continuous cropping for both corn (113 vs. 93 bu/ac) and soybean (38 vs. 35 bu/ac). The rotation benefit was greatest for corn during years with cool, wet spring weather and high summer temperature. The rotation effect for soybean did not vary with weather conditions. Spring weather conditions were more influential in determining yield of both crops to tillage and crop rotation practices than summer weather.
Technical Abstract: Reduced tillage, including no-till, and crop rotation are common practices for corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production in the Midwest. Benefits of no-till vary with latitude and cropping system. This study was conducted to evaluate the influence of weather on the effects of primary tillage (plow, disk, chisel, sub-soil, ridge-till, and no-till) and rotated and continuous corn or soybean over 16 years in southeastern Nebraska (fine, smetitic, mesic Aquertic-Typic Argiudoll). Corn and soybean yields were less with higher summer temperature. Only soybean yield increased with summer rainfall. Corn yielded less with no-till than with plow. Tillage by year interaction was significant for both crops; the yield advantage for plow was less during seasons with warmer spring temperatures. Yield of corn, relative to an environmental index, was similar for all tillage systems [i.e., slope between treatment yield and yearly experiment mean yield (the environmental index) were equal]. No-till and plow deviated most from the normal response due to varying spring temperature. Soybean yield, relative to the environmental index, was less with chisel than with other tillage treatments. Yield was greater with rotation than with continuous cropping for both corn (7.10 vs. 5.83 Mg ha-1) and soybean (2.57 vs. 2.35 Mg ha-1). The rotation benefit was greatest for corn during years with cool, wet spring weather and high summer temperature. The rotation effect for soybean did not vary with weather conditions. Tillage and rotation effects varied more due to spring weather conditions than to summer weather.