Preliminary study on effects of N,P and K on rice by "3414" fertilizer test

The field fertilizer tests with rice,including 3 factors,4 levels and a total of 14 fertilizer treatments,were carried out in order to study the parameters for rice to absorb and utilize fertilizers.The results showed that nitrogen affected rice yield mainly by increasing effective spikes,and phosphorus and potassium affected rice yield mainly by increasing filled grains and grain weight.Rational application of N,P and K fertilizers could significantly increase rice yield.The standard deviations of the yield increment rate,yield per unit nutrient and output/input ratio in different test plots were relatively small by N fertilizer but large by K fertilizer,especially by P fertilizer.The N,P and K contents of rice plants and seeds in the fertilization plots were higher than those in the plots without fertilization.The total amounts of N,P and K absorbed by aerial parts of rice plants were the highest in the optimal fertilization plots,higher in the P and K deficiency plots,smaller in the N deficiency plots,and the smallest in the plots without fertilization.The average fertilizer utilization ratio was 32.37% in N,4.21% in P and 31.35% in K.