Response Of Groundnut (Arachis Hypogaea) To Inoculation

'I'hough groundnut is nodulated by a number of rhizobia belonging to the cowpea miscellany, the nodulation and nitrogen (Nz) I'ixulion acliicvcd unclcr I'itrmcrs' conditions is ol'tcn inadequate. Studies at IC'K ISA I have attempted to overcome this by examining a large number of inoculant strains and various methods of' inoculation. Large variability between groundnut rhizobia in ability to fix N2 exists, but poor correlations between nodule mass and plant dry weight gains can occur. lnoculum size is important with nodule number and distribution and N2 fixation enhanced by heavier inoculation rates. Liquid inoculants have provided greater increases in yield than either granular or seed slurry inoculation, the latter method reducing germination and stand establishment. Several field trials at ICKISA'I', both in the rainy and irrigated, post-rainy seasons, have given significant responses to inoculation, even though the soil already contains lo4 rhizobialg. lhe cultivar Rohut 33-1 with strain NC 92 has eiven most consistent results