Effect of Cowdung, NPK AND Rhizobium Inocula on Nodules Number, Yield Contributing Attributes and Yield of Summer Mungbean (Vigna radiata) in Acid Soil

A field experiment was conducted to see the effect of cowdung, NPK and Rhizobium inocula on nodules number, yield contributing attributes and yield of summer mungbean (var. Binamoog-8), in acid soil at the farm of Agricultural Training Institute, Khadim Nagar, Sylhet from April to July, 2014. Seven treatments were viz. Control (without Rhizobium inocula and fertilizers), Cowdung (CD), CD+RI, NPK, NPK+RI, ½(NPK)+RI and Rhizobium inocula (RI). The rate of Urea-N, TSP-P and MoP-K were approximately 14, 14 and 17.5 kg ha-1, respectively. CD was around 8 t ha-1 and RI used approximately 45 g kg-1 seed. The randomly selected 5 plants were uprooted at four times in 30, 45, 60 and 90 days after sowing (DAS) for nodules. The individual ripened pod was picked at 15 days interval from 45 to 90 DAS. Treatments had significant effects on all studied characters except percent sterile pods plant-1 at 75 DAS, number of seeds pod-1 and 1000 seeds weight (g). Sole application of cowdung around 8 t ha-1 performed better in growth character, yield contributing characters which influenced to produce higher seed and stover yield (705 and 2031 kg ha-1), respectively. The highest nodules number were counted when crop treated with CD+RI and ½ (NPK)+RI which did not reflect on crop productivity for suppression of N2 fixing capacity in acid soil. Application of Rhizobium in alone or with other fertilizers had no significant influenced in yield due to soil acidity with coarse texture. The heavy rainfall also limits the higher productivity.