| In order to ascertain the effects post-crop soils and nitrogen fertilizer types on N2O emission from soil,we conducted a culture experiment about add ammonium sulfate,potassium nitrate,ammonium nitrate and urea fertilizer to the post-crop soils of bare soil,Soybean and Corn soil.The N2O emission rate of soil was sampled by intermittent closed culture method and analyzed by gas chromatography,The main research results are as follows:1.The trend of N2O emission from different post-crop soils are as follows:The N2O emission of soybean soil decreased with the culture time,but the bare soil and corn soil were stable and no significant difference.The total amount and average rate of N2O emissions are soybean soil>bare soil>corn soil.The N2O emission rate from bare soil and soybean soil were exponentially correlated with culture time,while N2O emission rate from corn soil was logarithmic correlated with culture time.2.The trend of N2O emission from different post-crop soils treated with ammonium sulfate are as follows:The N2O emission of bare soil increased with the culture time,soybean soil fluctuated most,and that of corn soil increased first and then decreased.The total amount and average rate of N2O emissions are soybean soil>corn soil>bare soil.The N2O emission rate of bare soil and corn soil was significantly quadratic function with culture time,but the correlation between N2O emission rate of soybean soil and culture time was not significant.3.The trend of N2O emission from different post-crop soils treated with potassium nitrate are as follows:The trend of N2O emission from bare soil and corn soil are stable and no significant difference,while the N2O emission from soybean soil is significantly higher and fluctuates with time.The total amount and average rate of N2O emissions are soybean soil>bare soil>corn soil.The N2O emission rate of bare soil was significantly quadratic function with culture time,and soybean and corn soil were exponentially correlated with culture time.4.The trend of N2O emission from different post-crop soils treated with ammonium nitrate are as follows:The N2O emission of soybean soil decreased with the culture time,Com soil showed a tendency of middle height,while that of bare soil was relatively stable.The total amount and average rate of N2O emissions are soybean soil>com soil>bare soil.The N2O emission rate of bare soil and com soil were significantly quadratic function correlation with culture time,while soybean soil was exponentially correlated with culture time.5.The trend of N2O emission from different post-crop soils treated with urea treatment are as follows:The trend of N2O emission of the three soils is similar to parabola,and the soybean soil and com soil were no significant difference.The total amount and average rate of N2O emissions are soybean soil>com soil>bare soil.The rate of N2O emission of bare soil and soybean soil were exponentially correlated with the culture time,while the com soil was significantly quadratic function with culture time.6.The total amount and average rate of N2O emission showed urea>ammonium sulfate>ammonium nitrate>potassium nitrate>CK,and there were significant differences among the treatments,whether it's the legume and non-legume soil of crops,or the bare soil.7.For emission model types,The emission patterns of ammonium sulfate and urea treatments in the three post-crop soils were the same,ammonium sulfate is an increasing type,and the urea belongs to the middle and high type.The emission patterns of the four treatments were the same between bare soil and com soil.The results show that the fertilizer emission pattern will not be changed by non-legume soil of com plant.8.The results show that the non-legume soil of corn plant can promote the nitrogen emission from ammonium sulfate and urea more,and the legume soil can promote the nitrogen emission from potassium nitrate and ammonium nitrate more.In summary,N2O emission from soil is affected not only by post-crop soils,but also by fertilizer types. |
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