'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