【摘要】 研究增温条件下冬小麦根系残体和秸秆在土壤中的分解系数的变异规律及影响因素,可为探讨农田土壤-作物系统碳循环对气候变暖的长期响应规律提供理论依据和数据支撑。为研究一个生长季的昼夜连续增温对冬小麦根系残体及秸秆分解系数以及分解后土壤酶活性等理化性质的影响,采集田间经过一个生长季昼夜增温处理的根系残体（W-根）和秸秆（W-秸秆）以及不增温处理（对照）的根系残体（CK-根）和秸秆（CK-秸秆）,设置W-根、W-秸秆、CK-根、CK-秸秆的4个添加处理,每个处理设置4个添加水平（0.3、0.6、0.9、1.2g）,将这些根系残体和秸秆添加到土壤中进行培养瓶培养,测定了不同处理下的土壤CO₂排放量及培养后的pH、水溶性有机碳（DOC）含量、脲酶活性、转化酶活性、过氧化氢酶活性。结果表明,土壤CO₂排放量与残体添加量之间存在极显著的一元线性回归关系,线性方程的斜率即代表了不同残体的分解系数。W-根的分解系数为（0.269 9±0.008 0） mg?g^-1?g^-1,显著高于CK-根的分解系数（0.240 7±0.009 0） mg?g^-1?g^-1;而W-秸秆的分解系数为（0.257 3±0.003 0） mg?g^-1?g^-1,CK-秸秆的分解系数为（0.258 7±0.015 0） mg?g^-1?g^-1,差异不显著（P>0.05）。不同处理下土壤CO₂排放量随土壤pH的增大而极显著（P<0.001）减小,随土壤DOC含量的增大而极显著（P<0.001）增大。不同处理下土壤CO₂排放量与土壤脲酶、转化酶、过氧化氢酶活性均存在极显著（P<0.001）的自然对数回归关系,土壤脲酶、转化酶、过氧化氢酶活性分别可解释75.7%（R²=0.757）、80.3%（R²=0.803）、92.7%（R²=0.927）的土壤CO₂排放量的变异。研究表明,增温显著提高了冬小麦根系残体的分解系数,但对冬小麦秸秆的分解系数无显著影响。根系残体和秸秆在土壤中分解所释放的CO₂量与酶活性存在自然对数回归关系。更多还原

【Abstract】 The theoretical basis and data support for the long-term response patterns of the soil-crop system carbon cycle to climate warming can be obtained by investigating the variations and influencing factors of the decomposition coefficients of winter wheat root residue and straw under warming condition. In order to investigate the effects of diurnal warming with one growing season on the decomposition coefficients of winter wheat residues（root and straw） and the soil enzyme activities and relevant physical and chemical properties, an indoor incubation experiment was performed. The winter wheat root residue and straw for the one-season diurnal warming and control treatments（coded as W-root, W-straw, CK-root, and CK-straw） were sampled in field. There were four treatments of W-root, W-straw, CK-root, and CK-straw, and each treatment included four amendment levels of 0.3, 0.6, 0.9, 1.2 g.These root residue and straw were added into the soil for incubation. Soil CO₂ emission and soil pH, dissolved organic carbon（DOC）content, and activities of urease, invertase, and catalase after incubation were measured. Results indicated that there was a significantly linear regression relationship between soil CO₂ emission and the amount of residue（root residue or straw） addition. The slope of the regression function represented the decomposition coefficient of crop residue. The decomposition coefficients for W-root and CK-root were（0.269 9±0.008 0） and（0.240 7±0.009 0） mg?g^-1?g^-1, respectively（the former was significantly higher than the latter）, while they were（0.257 3±0.003 0） and（0.258 7±0.015 0） mg?g^-1?g^-1 for W-straw and CK-straw, respectively（no significant difference with P>0.05）. Soil CO₂ emission decreased significantly（P<0.001） with the increase of soil pH but increased significantly（P<0.001） with the increase of soil DOC content. There were highly significantly（P<0.001） relationship between soil CO₂ emission and urease, invertase, and catalase activities. Urease, invertase, and catalase activities explained 75.7%（R²=0.757）, 80.3%（R²=0.803）, and 92.7%（R²=0.927） variations in soil CO₂ emission, respectively. Our results indicated that simulated warming significantly increased the decomposition coefficients of winter wheat root residue, but it had no effects on the decomposition coefficients of winter wheat straw. The relationship between the CO₂ emission rates from the soil with root residue and straw added and enzyme activity can be explained by the natural logarithmic models.更多还原