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EVALUATION OF MIXED CROP OF SORGHUM (SORGHUM BICOLOR (L.) MOENCH) AND LEGUMES
Abstract
Physiomorphological differences among crops in mixtures preclude precise predictions about their yield and nitrogen (N) use due to interspecific and intraspecific crop responses. A two-year field study at Mead, Nebraska evaluated how sorghum genotypes (Sorghum bicolor (L.) Moench), Martin and CK60 when intercropped with soybean (Glycine max (L.) Merril), cowpea (Vigna unguiculata (L.) Walp ) and mungbean (Vigna radiata (L.) Wilzek) affected crop yield and N use. Treatments involved 18 binary mixed crops of sorghum and legumes that were arranged within four-row plots in a replacement series and four-row monocultures of each crop. Sorghum grain production as well as total N uptake into grains and stover depended largely on the growth habit of the associated legume in both years. Tall cowpea significantly limited the yield and N uptake of sorghum while short cowpea enhanced yield and N uptake. Sorghum yield and N uptake were similar in sorghum-soybean and sorghum-mungbean mixtures and differed with sorghum within sorghum-cowpea in both years. More remobilization of N from stover to the grain occurred in 1983 than in 1982. This may have resulted from rainfall, temperature and cloud cover differences between the two years. Separate analysis for different legumes indicated for the most part linear response in yield and total N uptake among different mixtures with sorghum. Both land equivalent ratio (LER) and nitrogen land equivalent ratio (NLER) revealed that replacement of sorghum by legumes produced significant increases in legumes and vice versa. The competitive abilities of different crops intensified for N uptake as their cropping density increased but the efficiency of N use was greatest at low proportions. Both crops in various mixtures exceeded their "expected" monoculture values in grain yield, grain and stover N uptake parameters in most instances. Even when one species fell short of "expected" monoculture value, the other component crop of the mixture ultimately compensated for the inferior response in grain yield or N uptake. Total soil N at equal soil depths of different treatments was not statistically significant. This suggested that soil N was potentially available to all species in the mixtures and that differences between the crops in mixtures resulted from comparative abilities of individual species within the mixtures.
Subject Area
Agronomy
Recommended Citation
ODO, PETER EGWUONWU, "EVALUATION OF MIXED CROP OF SORGHUM (SORGHUM BICOLOR (L.) MOENCH) AND LEGUMES" (1985). ETD collection for University of Nebraska-Lincoln. AAI8602936.
https://digitalcommons.unl.edu/dissertations/AAI8602936