Agronomic characteristics of intercropped legume and cereal crops.

Abstract

Research was conducted in the summers of 1985 and 1986 at the University of Arizona Marana Agricultural Center, with the objectives of (1) determining the best intercropping species combination under near optimum irrigation, using three cereals (sorghum (Sorghum bicolor), maize (Zea mays), and pearl millet (Pennisetum americanum) and three legumes (field bean (Phaseolus vulgaris), cowpea (Vigna unguiculata), and soybean (Glycine max) in all combinations, and (2) identifying species genotypes best adapted to intercropping. Results from 1985 determined sorghum x soybean as the most appropriate intercropping combination for the environment of the Marana Agricultural Center. In the 1986 cropping season, three sorghum genotypes (Pioneer 8493, Funks G-522DR, and California IO80H40) were combined with three soybean genotypes (Asgrow A6242, Asgrow A6520, and Rillito), to identify the best genotype combination for intercropping. Both 1985 and 1986 experiments were carried out in a randomized complete block design with four replications. Pearl millet was the cereal with the greatest decrease in yield when intercropped, indicating that this cereal was not a good competitor with legumes. Sorghum was the best cereal competitor with the legumes and soybean was the best legume competitor with the cereals. Among the three sorghum genotypes studied in 1986, only Pioneer 8493 showed higher yield in monocrop whereas the other two genotypes yielded higher in intercropping, indicating some benefit from this system. On the average, all three sorghum genotypes showed intercropping to be advantageous, with high Land Equivalent Ratio values. Soybean genotypes showed drastic decreases in yield when intercropped. Asgrow A6520 soybean had the highest yield in intercropping. Sorghum #3 (California IO80H40) and soybean #3 (Rillito) were chosen as the most appropriate genotypes for intercropping, for the environmental conditions of the study.