昼夜增温对大豆田土壤N2O排放的影响

通过田间试验,用静态箱-气相色谱法测定N2O排放通量,研究昼夜增温对大豆田土壤N2O排放的影响.结果表明,增温没有改变大豆田土壤N2O排放通量的季节性变化规律.整个生长季,与对照相比,增温土壤N2O平均排放通量增加了17.31%(P=0.019),累积排放量显著增加了20.27%(P=0.005).对照与增温处理土壤N2O排放通量与土壤温湿度均呈显著性相关关系,对照与增温土壤的N2O排放温度敏感系数分别为3.75和4.10.整个生育期,增温显著增加了植株地上和总生物量、叶片硝酸还原酶活性和全氮含量,显著降低了叶片NO3--N含量;显著增加了土壤NO3--N含量,但对土壤有机碳及全氮含量没有显著影响.本研究表明,昼夜增温显著增加了大豆田土壤N2O的排放.

Effects of Diurnal Warming on Soil N2O Emission in Soybean Field

To investigate the impact of experimental warming on N₂O emission from soil of soybean field, outdoor experiments with simulating diurnal warming were conducted, and static dark chamber-gas chromatograph method was used to measure N₂O emission fluxes. Results indicated that: the diurnal warming did not change the seasonal pattern of N₂O emissions from soil. In the whole growing season, comparing to the control treatment (CK), the warming treatment (T) significantly enhanced the N₂O flux and the cumulative amount of N₂O by 17.31% (P=0.019), and 20.27% (P=0.005), respectively. The significant correlations were found between soil N₂O emission and soil temperature, moisture. The temperature sensitivity values of soil N₂O emission under CK and T treatments were 3.75 and 4.10, respectively. In whole growing stage, T treatment significantly increased the crop aboveground and total biomass, the nitrate reductase activity, and total nitrogen in leaves, while significantly decreased NO₃^--N content in leaves. T treatment significantly increased soil NO₃^--N content, but had no significant effect on soil organic carbon and total nitrogen contents. The results of this study suggested that diurnal warming enhanced N₂O emission from soil in soybean field.