The characteristics of the soil at the field experiment site were the same as those described for the soil used in the pot experiment, as the soil for the latter was taken from the same area as the site for the field experiment. Field preparation involved three plowings. A basal application of lime was made at a rate of 625 kg/ha. For high rate fertilizer treatment, N-P-K fertilizers (15-15-15) at rates of 28.13 kg/ha, 12.34 kg P/ha and 23.38 kg K/ha, respectively, were applied prior to planting, whereas in low rate fertilizer treatment, N-P-K fertilizers were applied at half the rate of the high rate treatment.