Plant-to-plant biomass and yield variability in corn-soybean rotations under three tillage regimes

Agronomic management practices have the potential to affect plant-to-plant variability of biomass accumulation and grain production. However, the relationship between the variability of crop production per plant (i.e., grain weight) and crop production per unit area (i.e., grain yield) is inconsistent because high variability in grain weight has been linked with lower yields in some instances but not others. The objective of this experiment was to investigate plant-to-plant variability of biomass accumulation and grain production at three developmental stages in corn (Zea mays L.)-soybean (Glycine max [Merr.] L.) rotations under conventional tillage, strip tillage, and no tillage. Plant-to-plant biomass variability, as measured by the coefficient of variation (CV) of crop biomass at three phenological stages, decreased throughout the growing season in corn but increased in soybean; these trends did not differ among tillage systems but did change among the 4 yr of the experiment. The CV of grain weight per corn plant was higher in no-till for two of the study years, suggesting an interaction between tillage and weather patterns that affects variability. Overall, mean grain weight per plant increased as CV of grain weight decreased in corn but not in soybean. This finding suggests that corn yields were maximized when all individual plants were producing relatively similar amounts of grain, whereas this relationship was not present in soybean. The findings of this study indicate that tillage practices do not consistently affect plant-to-plant variability of biomass or grain production and must be understood in context of weather conditions and other agronomic management practices.

Automated summary

This study found that the variability of plant-to-plant biomass accumulation and grain production in corn-soybean rotations is influenced by tillage practices and weather patterns. The variability of grain weight per plant was higher in no-till for two of the study years, indicating an interaction between tillage and weather conditions. Overall, corn yields were maximized when individual plants were producing similar amounts of grain, while this relationship was not present in soybean.