好气和厌氧条件下小麦秸秆的腐解特征研究

Characteristic of wheat straw decomposition under aerobic and anaerobic condition in soil

采用网袋培养法,研究在好气和厌氧条件,小麦秸秆腐解过程中碳、氮释放及纤维素、半纤维素和木质素的变化规律。结果表明：小麦秸秆在好气和厌氧条件的残留质量、碳和氮残留量均随培养时间的延长而降低,且呈前期（0～3个月）降解较快,而后（3～12个月）逐渐减缓的趋势。用一级动力学方程y=y0＋a·e^-kt对小麦秸秆在好气和厌氧条件的残留质量随时间变化进行拟合（决定系数R2均大于0.957）,质量腐解半衰期分别为72.8和121.9d,腐解速率常数（k）分别为0.022 0和0.014 0/d。在好气条件,小麦秸秆中碳和氮元素释放速率常数分别是其在厌氧条件的1.79和1.67倍,小麦秸秆中碳和氮元素的释放率分别是其在厌氧条件的4.39和1.40倍,且在培养至1个月时处理之间呈显著性差异（P〈0.05）。小麦秸秆中的纤维素、半纤维素和木质素残留量均随培养时间延长总体呈下降趋势。以上结果表明,好气条件更有利于小麦秸秆碳氮元素的释放及纤维素、半纤维素和木质素的降解,从而更有利于小麦秸秆的降解。

Net bag method was applied to determine the chemical composition （carbon, nitrogen mineralization, the residual quantities of cellulose,hemicellulose and lignin） during wheat straw decomposition process under aerobic and anaerobic condition in soil. Results showed that the residual mass,carbon and nitrogen of wheat straw sharply declined in the first 3 months,and then slowly decreased from 3 to 12 months incubation period. The decomposition of wheat residues mineralization could be quantitatively described by the first-order kinetics equation （the determination coefficient R2 〉0. 957）. Half-lives （t1/2） of wheat straw mass decomposition under aerobic and anaerobic conditions were 72.8 and 122.0 days, respectively, and the decomposition rate constants （k） of wheat straw mass were 0. 022 0 and 0. 014 0/d, under aerobic and anaerobic conditions respectively. The decomposition rate constants （k） of straw-C and straw-N in wheat straw under aerobic conditions were 1.79 and 1.67 times higher than those under anaerobic conditions,and the biggest variations were found at the end of the first month. Cellulose, hemicellulose and lignin residues in wheat straw were gradually increased during the whole incubation period. These results indicated that the straw decomposition under aerobic condition were higher than that in the anaerobic condition.