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秸秆还田后作物残体的分解是农田生态系统碳循环及养分周转平衡的一个至关重要环节.为了探索秸秆化学性质和土壤质地对黑土区土壤CO2排放和微生物量的影响,本文通过室内恒温培养实验研究了添加不同植株部位玉米秸秆(根、茎下部、茎顶部、叶)进入黑土区两种质地土壤(砂壤土和黏壤土)后的CO2排放、微生物量,并分析了它们与秸秆C/N、木质素含量的关系.结果表明,添加不同部位秸秆一致增加土壤CO2排放量,激发效应值介于216.53~335.17μmol·g-1,黏壤土大于砂壤土.激发效应值与木质素/N之间的线性回归关系明显好于激发效应与木质素含量、C/N、含氮量之间的线性关系.添加秸秆增加MBC和MBN含量,降低MBC/MBN,微生物群落氮固持的速率高于碳固持.添加秸秆后,砂壤土微生物量增加的幅度大于黏壤土,总溶解性氮含量小于黏壤土.结果说明,秸秆的木质素和氮含量均会对它的分解和CO2排放产生影响,木质素/N比木质素含量、C/N等更好地说明秸秆分解和CO2排放的差异;与黏壤土相比,在砂壤土中实施秸秆还田可以取得更好的土壤碳固存、微生物量和氮素保持效果.
The decomposition of crop residue after straw returning is a critical step in the carbon cycle and nutrient turnover balance of cropland ecosystem.In order to explore the effects of stalk chemistry and soil texture on soil CO2 emissions and microbial biomass in black soil region, The experiments were conducted to study the CO2 emission and microbial biomass after adding corn stalks (roots, stems, stems and leaves) from different plant sites to two soil types (sandy loam soil and clay loamy soil) in black soil area, and analyzed their relationship with straw C / N, lignin content.The results showed that adding different parts of straw consistently increased soil CO2 emissions, the excitation effect value ranged from 216.53 to 335.17μmol · g-1, the clay loam soil was larger than sandy loam soil.The excitation effect value and lignin / N was significantly better than that of the lignin content, C / N and nitrogen content.With the addition of straw to increase MBC and MBN content and MBC / MBN, the rate of nitrogen fixation in the microbial community was high After the straw was added, the increase of microbial biomass in sandy loam soil was larger than that in clay loam soil, and the total dissolved nitrogen content was less than that of clay loam soil.The results showed that the lignin and nitrogen content of straw would Its decomposition and CO2 emissions have an impact on the lignin / N than lignin content, C / N and so on to better explain the straw decomposition and CO2 emissions differences; compared with clay loam, sandy loam implementation of straw in the field can Achieve better soil carbon storage, microbial biomass and nitrogen retention.