Effect of nitrogen on yield, yield attributes and quality of soybean (Glycine max) intercropped with cereals in foot-hills of Uttar Pradesh

A field experiment was conducted during rainy season of 1992-93 and 1993-94 to study the effect of N on yield, yield attributes and quality of soybean in soybean [Glycine max (L.) Merr.] + maize (Zea mays L.) and soybean + sorghum [Sorghum bicolor (L.) Moench] intercropping systems. The treatments consisted of 4 levels of N (0, 50, 100, 150 kg N/ha) for each of intercropping systems of soybean + maize and soybean + sorghum in alternate rows of 60 cm and with and without recommended dose of N for each sole crop. Number of branches, number of pods, number of seeds/pod, 1,000-seed weight, seed and straw yields and protein yield of soybean decreased significantly when intercropped with maize or sorghum. The maximum branches/plant, pods/plant, seeds/pod and 1,000-seed weight of intercropped soybean system were recorded with 50 kg N/ha in either of intercropping systems. Soybean + maize system fertilized with 50 kg N/ha recorded the highest seed yield (1,088.3 and 767.6 kg/ha) of intercropped soybean, during both the years. Almost similar pattern of seed (796.6 and 770.6 kg/ha) and straw yields (1,633.0 and 1,781.0 kg/ha) of intercropped soybean were also observed in soybean + sorghum system. With increasing the dose of N above 50 kg/ha showed detrimental effect on yield attributes, seed and straw yields of intercropping soybean in both the intercropping system. Protein content of soybean seed was not significantly affected by N, although it improved with N, the highest protein yield of intercropped soybean was recorded under 50 kg N/ha.