Effect of big granulated urea and it's rational application on paddy rice

Studied on the effects of Urea types on rice growth and rational application of N, P fertilizers on rice by means of Quadratic Saturated D-Best Design. The results showed that nitrogen was the key constructive factor to rice yield. The height of stalk, the length of ear, the granulates of ear and the ears of every stem are increased notably after supplying N fertilizer. The effect of big granulated Urea was better than common Urea on rice growth characteristics and yield. However, high quantity of N fertilizer reduced ear rating and the weight of grains. Therefore,the yield was decreased. It was needed to applying N and P fertilizers coordinately and rationally. The amount of maximum profit of N and P(P_2O_5)should be 168 kg/hm~2 and 47.6 kg/hm~2 respectively.