Effects Of Different Fertilization Techniques On The Emission Of Methane And Nitrous Oxide From The Rice-wheat Rotation Cropland Of Chao Lake Basin

To evaluate different fertilization techniques on the emissions of farmland greenhouse gases of Chaohu Lake basin,in October 2012 to October 2013,, in view of the emissions of CH4 and N2O from Chaohu basin farmland, setted four treatments include regular fertilization, optimized fertilization, loss-control fertilizer and optimized fertilization+ urease inhibitors in the Chaohu experimental station of agricultural non-point source pollution, every treatment repeated three times, and every experimental plot is 30 m2, observation of the whole growth stages of the winter wheat and single crop-rice of Chaohu Lake basin with closed static box-gas chromatography method, in through the field observation, researched the emission rules of CH4 and N2O from the winter wheat field and the quarterly paddy of Chaohu Lake basin, getted following conclusions mainly:1. The daily variation regularity of CH4 emission from wheat field is obvious with the temperature change of day and night, it is a positive correlation; The daily variation regularity of N2O emissions is relatively complex, it is positively correlated from around 6 o’clock in the morning to two in the afternoon with the temperature variations,and it is Negatively Correlated from 2 PM to 6 o’clock in the next morning.2. The seasonal variation regularity of CH4 emissions from wheat field shows three emission peaks, which is related to the fertilization conditions and the growth of wheat; The seasonal variation regularity of N2O emission has no significant peak, it occurs mainly in wheat seeding early period with base fertilizer, before the winter and the later growth period.3. The emission of greenhouse gases from wheat field is N2O mainly, the contribution rate of CH4 to the emission of greenhouse gases from wheat field is 24.21% to 38.15%, the comprehensive greenhouse effect of treatments is:optimized fertilization> regular fertilization> optimized fertilization+urease inhibitor> loss-control fertilizer> blank control treatment, and it is no significant difference;The unit production GWP of the treatments is:regular fertilization> optimization fertilization> loss-control fertilizer> optimized fertilization+urease inhibitors> blank control treatment.4. The daily variation of CH4 emission from rice paddy appears two peaks in the afternoon and the evening respectively when the temperature is relatively low,the emission of CH4 is rather low with the highest temperature at noon, and it is a negative correlation; the daily variation of N2O emission shows three peaks, which occurs at six in the morning, at two in the afternoon and ten in the evening respectively.5. The seasonal variation regularity of CH4 emissions from rice paddy is "twin peaks", which appeares in the tillering period and booting up flowering period respectively, in the first emission peak:the peak value regular fertilization> optimized fertilizer+urea enzyme inhibitor> optimize fertilization> loss-control fertilizer> blank control treatment, in the second emission peak:the peak value of optimized fertilization> conventional fertilization> loss-control fertilizer> blank control treatment> optimal fertilizer+urea inhibitor. The seasonal variation regularity of N2O emission is "unimodal type", and there are also two small emission peaks in roast field period and after earing fertilizer espectively, the emission rate of N2O in the presence of maximum peak from big to small in turn is: optimized fertilization> regular fertilization> loss-control fertilizer> optimal fertilizer+ urea inhibitor> blank control treatment, the emission of N2O is mainly concentrated in front of the stage baking and bake field.6. The emission of greenhouse gases from paddy are mainly composed of CH4 emission, the contribution rate of N2O emission is less than 3.02%, the comprehensive greenhouse effect of all the treatments is:optimized fertilization> rrgular fertilization> loss-control fertilazer> optimized fertilization+urease inhibitors> blank control treatment. The comprehensive greenhouse effect of optimized fertilization+urease inhibitors relative to the conventional fertilization and optimized fertilization y 868.65 Kg·eqCO2·hm-2 and 1196.34Kg·eqCO2·hm-2 respectively; The comprehensive greenhouse effect of loss-control fertilizer relative to the conventional fertilization and optimized fertilization is decreased by 597.63Kg·eqCO2·hm-2 and 925.32 Kg·eqCO2·hm-2; respectively The unit yield of GWP is minimal. On the whole, the value of the unit output of the GWP in the turn is:optimized fertilization> regular fertilization> loss-conrol fertilizer> blank control treatment> optimized fertilization+urease inhibitor. The value of unit production GWP of the optimized fertilization+urease inhibitor and loss-control fertilizer is 1.00 and 1.15 respectively, and is decreased by 14.53% and 1.71% respectively to the regular fertilization.7., The comprehensive greenhouse effect of treatments under the rice and wheat rotation of Chaohu basin is:optimize fertilization> regular fertilization> loss-control fertilizer> optimized fertilization+urease inhibitors> blank control treatment, the emission of greenhouse gas from rice paddy is primary cause, the greenhouse effect of wheat season is less than rice seasonof the annual greenhouse effect; The greenhouse effect of CH4 from farmland in more than N2O, and the paddy is the largest.