Effect of Rhizobium Inoculation, Phosphorus and Molybdenum in Yield, Yield Attributes and Nodulation of Cowpea under Mulched and Un-Mulched Field Condition

Cowpea is an important source of nutrition being popular in Nepal. In order to study its effect on nodulation, yield and yield attributes, a research was conducted in the sandy loam soil of the horticulture farm of Agriculture and Forestry University in 2018. The experiment was laid out in factorial 2×5 RCBD which consists of mulched and un-mulched condition as 1st factor and rhizobium inoculation (R) at 1gm/ 16.66 gm seed, phosphorus (P) at recommended dose of 120kg/ha, use of R plus P (RP), RP plus Molybdenum (RPMo) at 2 gm per kg seed and control with no such application as 2nd factor. So altogether there are ten treatments with three replications. Regarding 1st factor, mulched treatment was found significantly superior than un-mulched treatment in case of all yield attributes like canopy, stem diameter and plant height. Yield and no of nodules per plant was found 312.61 gm and 121.63 respectively in mulched treatment which was highly significant (P < 0.001) than un-mulched. In case of 2nd factor, plant height at 60 days after sowing was found significantly superior in all applications than control. Yield and no of nodules per plant was found 312.53gm (P < 0.01) and 129.33 (P < 0.05) respectively in RPMo treatment which was statistically significant and at par with P, RP and R treatment respectively and lowest in control. The rise in number of nodules due to the different treatment applications had the high positive correlation (P < 0.01) with yield and yield attributes. There was no any significant interaction between the two factors. Use of mulching and RPMo treatment was found to be the most suitable combination for cowpea in sandy loam soil