Effect of Rhizobium inoculation, phosphorus and time and methods of nitrogen application on growth and yield of spring blackgram (Vigna mungo (L.) Hepper) and its residual effect on succeeding fodder sorghum (Sorghum vulgare L.)

Abstract

Grain yield of blackgram or urdbean, a popular and highly proteinaceous pulse crop of India, is very low. This is possibly because of its cultivation on marginal and submarginal lands of low soil fertility where little attention is paid to adequate fertilizer, especially phosphorus and nitrogen. Although large achievements have undoubtedly been made in plant nutrition in cereals like wheat and rice, much less attention has been devoted to the development of suitable agro-techniques for production of pulses, especially blackgram. Inoculation with efficient Rhizobium strains and fertility management are important in the production technology of this crop. Though blackgram is regarded as excellent in symbiotic nitrogen fixation, many workers (Pate & Dart, 1961; Shanthakumari & Sinha, 1974) have opined that actual nitrogen fixation starts about 3 weeks after sowing and the senescence of nodules after profuse flowering. This results in nitrogen hunger at initial stages of crop growth as well as in the reproductive stage. Beneficial effects of starter nitrogen in blackgram have been reported by some workers (Singh et al. 1975). However, symbiotic nitrogen fixation may not be adequate to satisfy the N need of developing pods. Since no information is available on the effect of top dressing of nitrogen in the reproductive phase, the present investigations were planned to study the effect of Rhizobium. inoculation and phosphorus as well as time and method of N application on growth and yield of blackgram and its residual effect on fodder sorghum.