Relation between Manuring Method of Granular Compouud Fertilizer : Its Manurial Effect on Paddy Rice in Comparison with Mixed Fertilizer

Abstract

The manurial effects of a granular compound fertilizer, as basal dressing at different applying periods on the paddy rice, were examined in the field experiments for the last 2 years. Besides the above, the plots of mixed fertilizer (consists of ammonium sulfate, superphosphate and potassium sulfate) which contains the same quantities of N, P_2O_5 and K_2O respectively as in the compound fertilizer, were prepared for comparison. The results show that in the case of the mixed fertilizer, the manurial value was most effective when the fertilizer was applied, being mixed with soil immediately before irrigation, while in the case of the compound fertilizer, it was most effective when that was applied in barrow-operation after irrigation. The manurial effect in the latter case was larger than that in the former case, if the both were compared with each other. The differences of these manurial effects were caused probably by those of nitrification, solubility and movement of NH_4-N in soil.