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在内蒙古农牧交错带,选择4个邻近、不同开垦年限(5、10和50 a)的农田,分别记为C5、C10和C50,以及天然草地作为研究样地;利用静态箱法,在2008—2010年作物生长季(4—10月)进行野外原位试验,研究了土地利用变化对N2O排放量的影响.结果表明:草地与C5、C10、C50农田土壤的N2O排放量在2008—2010年作物生长季均存在显著差异,F分别为53.8、17.3和153.0(P均小于0.001),草地N2O排放量分别为87.6、91.8和211.0 mg/m2.在2008—2010年作物生长季,C5和C10农田土壤N2O排放量比草地低10%~50%;随着开垦年限的增加,N2O累积排放量增加,C50在作物生长季的N2O排放量比草地高10%~30%.草地和不同开垦年限的农田土壤在作物生长季内N2O排放量的58.1%受土壤w(NH4+-N)和含水量的综合影响(R2=0.58,P<0.01).
In the ecotone between agriculture and animal husbandry in Inner Mongolia, 4 adjacent farmlands with different years of reclamation (5, 10 and 50 years) were selected as C5, C10 and C50, and natural grassland was used as the research sample. By static box method, - 2010 in situ crop growth season (April-October) field experiments to study the impact of land-use changes on N2O emissions.The results show that: grassland and C5, C10, C50 farmland soil N2O emissions in 2008-2010 There were significant differences in annual growth seasons with F values of 53.8, 17.3 and 153.0 (P <0.001) and N2O emissions of 87.6, 91.8 and 211.0 mg / m2, respectively. During the 2008-2010 crop season, The N2O emission of C10 farmland was 10% ~ 50% lower than that of grassland, while the cumulative emission of N2O increased with the increase of reclamation age, while the N2O emission of C50 was 10% ~ 30% higher than that of grassland during the growing season. 58.1% of the N2O emissions of farmland soil with years of crop growth season were affected by the combined effects of soil moisture (NH4 + -N) and water content (R2 = 0.58, P <0.01).