Effect Of Simulated Experimental Warming And Acid Rain On N₂O Emission From Soybean-Winter Wheat Rotation System

Global warming and acid rain are the most important problems in the world. As the important greenhouse gas, the emission flux of N2O produce the problems of global warming and acid rain. And the cropland is the main emission source. To investigate the impact of experimental warming and acid rain on N2O emission from field ecosystem, field experiment was carried with one winter wheat growing season and two soybean growing seasons. Seting four treatments include the control treatment(CK), the warming treatment(T), the acid rain treatment(S) and the warming with the acid rain compound treatment(ST). Measured the N2O emission fluxes by using static dark chamber-gas chromatograph. Analysed the crop biomass, the plant nitrogen metaboliam index and the organic carbon, total nitrogen content and nitrate nitrogen content in soils. Discussing the influencing laws and possible influencing mechanism of experimental warming and acid rain on N2O emission from field ecosystem, view to offer scientific basis to forecast the emission of field ecosystem greenhouse gas, under the circumstances of the earth’s surface climate warming. Results indicate that:Comparing to the control treatment (CK), the warming treatment (T) significantly reduced the N2O flux and the cumulative amount of N2O from the whole system. While the S and ST treatments enhanced the N2O flux and the cumulative amount of N2O from the soil-winter wheat system, signficantly. In the whole growth period, the magnitude of each treatment N2O mean emission is:S>ST>CK>T, and the cumulative amount of N2O is:ST>S>T>CK. Comparing to the control treatment (CK), the T, S and ST treatments all enhanced the N2O flux and the cumulative amount of N2O from the winter wheat soil. And in the whole growth period, the magnitude of each treatment N2O mean emission from is:ST>S>T> CK. The significant correlations were found between soil N2O emission and soil temperature of the four treatments. Except the T treatment, the else three treatments all had significant correlations between soil N2O emission and soil moisture.The warming treatments(T) changed the correlation between soil N2O emission and soil moisture.The T and ST treatments didn’t significantly change the N2O flux and the cumulative amount of N2O from the soil-soybean system, but the S treatments increased them.In the whole growthing period, the magnitude of each treatment N2O mean emission from is:S>ST>T>CK. Comparing to the CK treatment, the T and S treatments added the mean N2O flux from the soil,significantly, but the ST treatment significantly decreased the N2O flux. In the whole growthing period, the magnitude of each treatment N2O mean emission from is:T>S>CK>ST. The correlations of the four treatments between the soybean soil N2O emission and the moisture are significant. But the significantly correlation between the soil N2O emission and the soil temperature is only found in T treatment.