Effect of N disposable application rates on the growth and yield of rice with plastic film covering

【Objective】 Exploration was done on the effect on rice growth and yield of the different N disposable application rates under the condition of film mulching cultivation.【Method】 High quality rice "Liang-you 6326" was used as plant material.Five different designs:0(CK),75,150,225,300 kg/hm2 of the Nitrogen Fertilizer were applied before film mulching.The tiller number was counted once every week after transplanting.Then the effect photo out,chlorophyll content and yield were measured one week before initial heading stage,full heading time and harvest time of the rice.The best N application rate was analyzed by economic benefit of curve fitting.【Result】 In the experiment,with the increase of the N application rate,the physiological indexs of photo out,chlorophyll content and the tillers all increased.But the yield showed a decreasing tendency when the yield increased to a certain degree.N application had no significant effect on photosynthetic parameters,such as:cond out,ci out,trmmol out and leaf except the photo out.When the Maximum N application rate was 300 kg/hm2,the chlorophyll content was 48.38 mg/g,the highest at initial heading stage,and the tillers per hill reached 44.42 ind.But there was no obvious difference with the nitrogen application 225 kg/hm2,the effective panicle number reached 225.60×104 plants/hm2,and yield reached 10 062.57 kg/hm2.【Conclusion】 Through the nonlinear curve fit,the results showed that:285.37 kg/hm2 was the best N disposable application rate under the condition of film mulching,and 10 062.57 kg/hm2 was the highest theoretical yield.