Study on the Relationship between Fertilizer Level and Yield of Paddy Rice under the Condition of Controlled Irrigation

In order to study the relationship between fertilizer level and yield of paddy rice under the condition of controlled irrigation,three times repeated experiments had been tested based on the rice variety of longdun 104 with different fertilizer levels.The results showed that the fertilizer level had a very significant correlation with yield from the fertilizer 180 kg/hm2 to 480 kg/hm2,in existing fertilization technology condition,higher fertilizing amount took less yield increase,the yield reached a new high with the fertilizer level with 420 kg/hm2,when the fertilizing amount exceeded 420 kg/hm2,the yield decreased.If the fertilizer level was controlled to the limit of 200 kg/hm2,the yield should increase properly on the base of 7 500 kg/hm2.In guarantee of per unit yield,the fertilizing amount should be less than 400 kg/hm2.