EFFECT OF MICRONUTRIENTS ON YIELDS, NITROGEN-FIXATION BY SOYBEAN (GLYCINE-MAX) AND ORGANIC-CARBON BALANCE IN SOIL

A field experiment on soybean was conducted during rainy season of 199 1 and 1992. Nine treatments, viz, zinc @ 5.0 kg and 10.0 kg/ha, boron @ 0.5 kg and 1.0 kg/ha, molybdenum @ 0.5 and 1.0 kg/ha, farmyard manur e @ 10 tonnes/ha and 2 controls (inoculated + recommended N. P, K and non-nodulated + recommended N, P, K) were tested. Grain yield, total b iomass yield, symbiotic nitrogen fixation and organic carbon in soil a fter the harvest increased significantly with micronutrients applicati on over the controls except B @ 1.0 kg and Mo @ 0.5 kg/ha for grain an d biomass yield during 1992. Maximum increase in biomass 52.0 and 28.9 %, nitrogen fixation 13.5 and 19.3% and organic carbon of soil 38.8 an d 43.9% were recorded with zinc @ 10.0 kg/ha during 1991 and 1992 resp ectively.