Effect of Superphosphate on the Yield of Wheat and Rice oil Acid Soil of Nagaland and Nutrient Content of Grain

In acid soil of Nagaland both wheat and rice responded to phosphorus applied as superphosphate. The optimum dose was 80 kg P₂O₅/ha. Residual effect of phosphate on wheat was also significant. Phosphate application increased the available P in soil and its uptake by grain. Availability of Ca and K and their uptake were not markedly changed. Soil available micronutrients (Cu, Zn and Fe) were significantly decreased except iron in rice soils. Higher doses of P significantly depressed Cu uptake in both the crops and 80 kg P₂O₅/ha produced the highest increase in the uptake of Zn and Fe by wheat and rice.