Rotation, tillage, and variety main effects on grain yield were all significant in 2002. Rice grain yield, over all treatment combinations, averaged 159 bu/acre, which was 22 bu/acre more than in 2001. Grain yields for the two 3-phase rotations were 180 bu/acre for the rice-corn-soybeans rotation and 177 bu/acre for the rice-corn (wheat)-soybean rotation. These yields were slightly better than the 174 bu/acre yield from the rice-soybean rotation and 165 bu/acre from the rice-corn rotation. Grain yield declined 13 bu/acre in the continuous rice treatments when compared to 2001 yields and 27 bu/acre from the 2000 yields. Plant growth was poor in all the continuous rice plots with leaf nitrogen (N) levels lower than in other rotations. Conventional tillage treatment combinations yielded 17 bu/acre more than the no-till combinations, but this difference varied between rotations. For the continuous rice rotation, the conventional-till yielded 37 bu/acre more than the no-till whereas the same difference was 14 bu/acre in the rice-soybean rotation. There was a non-significant 7 bu/acre increase in rice yield over all treatment combinations with the 'enhanced' fertility treatments when compared to the 'standard' fertility treatments. Wells yielded a non-significant 7 bu/acre better than LaGrue across all treatments. Rice grain yield from the two rotations where rice was planted after wheat averaged 144 bu/acre-significantly higher than any previous year. There was an overall yield loss of 12 bu/acre from no-till when compared to conventional tillage, a 4 bu/acre gain from increased fertility, and a 16 bu/acre gain from the variety XL-7 when compared to RU1093. Of all the treatment combinations in this comparison the no-till rice (wheat)-soybean (wheat) rotation using enhanced fertility and the variety XL-7 was the most productive with a rice yield of 181 bu/acre and a wheat yield of 77 bu/acre. Overall, irrigation-water use declined from the previous year with an average of 26 inches needed for the conventional till treatments and 24 inches for the no-till treatments. Continuous rice needed only 17 inches of irrigation while all other rotations required between 28 and 32 inches.
