RICE CULTURE The Effect of Rotation, Tillage, Fertility, and Variety on Rice Grain Yield

Average grain yield for the full-season varieties, over all treatment combinations, was 165 bu/acre. This average was impacted primarily by variety differences with ‘Wells’ averaging 180 bu/acre and ‘Cybonnet’ averaging 152 bu/acre. There were no significant differences between rotation, tillage, or fertility main-effect treatments. Summaries of grain yields for the main effect of tillage indicated that no-till treatments were equal to or higher than conventional-till treatments in 6 of 7 years. In all 7 years, lowest grain yields were from the continuous rice rotation while highest yields were from the two rotations that included rice every third year. There was no difference in rice-grain yields in the two-phase rotations that had either soybeans or corn as alternate crops. Fertility had no significant effect on grain yield in any of the 7 years summarized in this study. Variety differences occurred only after Cybonnet was introduced to the study as a replacement for ‘LaGrue’. Summarized results illustrate a potential to reduce production costs by reducing or eliminating tillage and reducing fertilizer rates. Low grain yields in the continuous rice rotation are a concern only if they are sufficiently low to reduce net returns below those of alternate crops used in the rotation.