Response of summer urdbean (Vigna mungo L.) to zinc, molybdenum and Rhizobium

A field experiment was carried out during two summer seasons of 2011 and 2012 at Faizabad, Uttar Pradesh to study the effect of zinc, molybdenum and Rhizobium on growth, yield attributes and yield of urdbean (Vigna mungo L. Hepper). On an average, application of 7.5 kg Zn ha⁻¹ to urdbean significantly resulted in higher number of primary (26) and secondary branches (4.3), nodules number at 35 and 45 days after sowing-DAS (7.1 and 5.8 plant⁻¹, respectively), dry weight of nodules at 35 and 45 DAS (8 and 14.3 g plant⁻¹, respectively), pods plant⁻¹ (20.3), seeds pod⁻¹ (7.1) and 100-seed weight (3.9) over 2.5 kg Zn ha⁻¹ and control treatment but it was statistically at par with 5 kg Zn ha⁻¹. Further, seed yield was increased by 5.2, 9.6 and 10.7% over the control following application of 2.5, 5.0 and 7.5 kg Zn ha⁻¹, respectively. Seed yield was highest at 1.0 kg Mo ha⁻¹, but it was statistically at par with 0.5 kg Mo ha⁻¹. Net return and benefit: cost (B: C) ratio were higher under the treatment receiving 2.5 kg Zn ha⁻¹ and 0.5 kg Mo ha⁻¹. Presowing inoculation of urdbean seeds with Rhizobium enhanced crop growth, yield attributes, seed (11.8 q ha⁻¹) and straw (21.3 q ha⁻¹) yield over uninoculated control. Net return and B: C ratio were also higher with inoculated treatment.