Growth pattern, physiological indices and productivity of different soybean (Glycine max) based intercrops as influenced by nitrogen nutrition

Abstract

A field experiment was carried out during kharif 2009 and 2010 to study the performance of maize (Zea mays L.), sorghum [Sorghum bicolor (L.) Monech] and pearlmillet [Pennisetum glaucum (L.) R.Br. Emend Stuntz] inter- cropped in soybean [Glycine max (L.) Merrill] in 1:2 ratio in additive series with varying levels of nitrogen (N) vis-- vis the sole stand of intercrops and soybean with recommended dose of N at the research farm of Indian Agricul- tural Research Institute, New Delhi. Application of 75-100% of recommended dose of N (RDN) to maize inter- cropped with soybean recorded higher values of growth parameters. Sorghum plant height, dry matter, leaf area index (LAI) and crop growth rate (CGR) were significantly influenced upto 75% RDN in intercropped stand and they were comparable to higher N level and sole sorghum. Plant height, dry matter accumulation, LAI and CGR of intercropped pearlmillet was at par with sole stand. Of these parameters, plant height and dry matter accumulation found increasing with increasing levels of N upto 50% RDN, while LAI and CGR of intercropped pearlmillet in- creased significantly upto 75% RDN. The seed yield per cob, seed index and the seed yield of intercropped maize was maximum with 100% recommended dose of nitrogen (RDN) indicating that there was no significant contribu- tion of BNF from intercropped soybean to maize. In case of sorghum, the test weight and biological yield recorded significantly higher values from 50% RDN to intercropped sorghum onwards and comparable to sole crop with 100% RDN. The grain yield on plant population basis was higher with 75% RDN to intercropped sorghum. In pearlmillet, the ear length and test weight increased significantly only up to 50% RDN, however the grain yield was significantly superior up to 75% RDN in 2009 and upto 50% RDN to intercropped pearlmillet during 2010.