Response of vegetable cowpea to phosphorus and biofertluzers in old alluvial zone of west bengal

A field study on vegetable cowpea (ev. Bidhan Barbati-1l was conducted during pre-kharifseason of 1999 and 2000 to study the effect of phosphorus and biofertilizers (Rhizobium and phosphatesulubilizing bacteria) on nodulation and yield in a sandy-loam soil of Old Alluvial Zone, West Bengal, Four levels of phosphorus (0, 40, 60, 80 kg/ha) as main-plot treatments and four sub-plot treatments comprising no inoculation, single inoculation with Rhizobium and Phosphate-solubilizing bacteria, dual inoculation with both of them were arranged in split-plot design with three replications. Phosphorus fertilization increased the pod yield and nodulation significantly up to 80 kg/ha. Single or dual inoculation with biofertilizers resulted in conspicuous increase in nodule number and weight, leg-haemoglobin content and Nitrogenase activity of nodules and pod yield over no inoculation. However, dual inoculation with Rhizobium and Phosphate-solubilizing bacteria resulted better response than their individual inoculations. Economic evaluation revea1ed that dual inoculation with biofertilizers gave maximum net return and B/C ratio.