Rhizobium and Phosphorus Interaction on N-P Uptake and Dinitrogen Fixation by French bean (Phaseolus vulgaris L.) in an Acid Alfisol from North-west Himalayas

摘要

Dinitrogen fixation by grain legumes is an effective and economic way of providing nitrogen in the crop-livestock-farming system. Phosphorus plays an important role in the nutrition of legumes and improves biological nitrogen fixation. Rhizobium inoculation along with phosphorus application has a favourable effect on total factor productivity (Gupta and Sharma 1989). French bean (Phaseolus vulgaris L.) is considered to have little ability to fix atmospheric dinitrogen owing to host genotype, rhizobiastrain, the influence of environment on these isolates and their symbiosis (Giller 1990). To obtain economically attractive yield and to reduce external inputs and to improve the use of renewable source of energy, it becomes imperative to select the most efficient and competitive strains of rhizobia for French bean crop along with optimum level of phosphorus for getting the maximum N-P uptake and dinitrogen fixation by this crop. The population of specific Rhizobia i.e. Rhizobium leguminosarum bv. phaseoli causing nodu-lation in French bean varies from 2.5 x 10~2 to 218 x l0~2 in the soils of Himachal Pradesh (Dubey et al. 2007). Keeping this in view, the present study was done to select the most efficient strains of Rhizobium leguminosarum bv phaseoli along with different phosphorus levels on N-P uptake by French bean (Phaseolus vulgaris L) on the phosphorus deficient acid Alfisol from northwest Himalayan region.