【摘要】 为了探明秸秆腐解的最佳初始条件,为腐熟秸秆还田提供科学依据,以水稻秸秆为腐解对象,设置不同的"金葵子"腐秆剂用量(因素A:A₀、A_0.5、A_1.0;%)、含水量(因素B:B₅₀、B₆₀、B₇₀;%)及初始碳氮（C/N）比(因素C:C₂₀、C₂₂、C₂₅)等初始条件,进行正交试验,研究水稻秸秆腐解过程中pH、种子发芽指数（GI）、C/N比、腐解率（DR）、水溶性有机碳（DOC）及紫外光谱参数(SUVA₂₈₀、E₂/E₃和A_226-400)等指标的动态变化,以确定这些初始条件对水稻秸秆腐解性能的影响。结果表明,（1）在腐解过程中,所有处理GI和DR值均随着腐解的进行逐渐升高;A₀B₇₀C₂₅和A_0.5B₇₀C₂₂处理C/N比持续下降,其他处理先升高后下降;A₀B₅₀C₂₀和A_1.0B₇₀C₂₀处理DOC含量先升高后下降,其他处理持续升高,紫外光谱参数的变化反映了水溶性有机物芳香性结构和腐殖化程度变化情况。（2）腐解结束时,未腐熟完全的A₀B₅₀C₂₀处理pH、GI和DR值（分别为7.05、34.9%和30.7%）明显较低,其C/N比（25.7）则明显较高,而大多数处理pH值符合腐熟堆肥标准（8.00-9.00）,GI值符合毒性较低（≥50%）或完全腐熟状态（≥80%）;A₀B₇₀C₂₅、A_0.5B₇₀C₂₂和A_1.0B₆₀C₂₅处理C/N比（分别为13.1、14.4、16.4）基本符合腐解产物最佳C/N比标准（15.0）;A_0.5B₇₀C₂₂处理DR值（47.1%）最高。通过紫外光谱参数测定来预测GI值大小,为判断秸秆是否腐熟完全提供了一种替代性评价方法。直观分析法表明,水稻秸秆腐解最佳初始条件为"金葵子"腐秆剂0.5%、含水量70%、初始C/N比25;腐秆剂用量对DOC含量影响最大,含水量对C/N比、DR、SUVA280、E₂/E₃和A_226-400值影响最大,初始C/N比对pH和GI值影响最大。更多还原

【Abstract】 In the present study, the effect of different "Jinkuizi" decomposition agent dosages(Factor A: A₀, A_0.5, and A_1.0; %),moisture contents(Factor B: B₅₀, B₆₀, and B₇₀; %), and initial C/N ratios(Factor C: C₂₀, C₂₂, and C₂₅) on rice straw decomposition was investigated using an orthogonal test design, in order to find out the best initial conditions for decomposing straw and provide a scientific basis for decomposed straw returning to the fields. Decomposition indicators such as pH, germination index（GI）, C/N ratio, decomposing ratio（DR）, dissolved organic carbon（DOC）, and ultraviolet spectral parameters(SUVA₂₈₀, E₂/E₃, and A_226-400)were analyzed. Results showed that during the decomposition period, the GI and DR values for all treatments gradually increased as the decomposition progressed. The C/N ratios for the A₀ B₇₀ C₂₅ and A_0.5 B₇₀ C₂₂ treatments continuously decreased, while those for the other treatments first increased and then decreased. The DOC contents for the A₀ B₅₀ C₂₀ and A_1.0 B₇₀ C₂₀ treatments first increased and then decreased, while there was an increasing trend for the other treatments. The variation of aromatic structure and humification degree of dissolved organic matter was well linked to the variations of ultraviolet spectral parameters obtained from the rice straw compost. At the end of the decomposition period, the p H, GI, and DR values（7.05, 34.9%, and 30.7%, respectively） declined dramatically, whereas the C/N ratio（25.7） was very high in the incompletely decomposed A₀ B₅₀ C₂₀ treatment. For all the employed treatments(except A₀ B₅₀ C₂₀), the pH values were found in accordance with the required standard of compost maturity（8.00-9.00）,while the higher GI values indicated low toxicity（≥50%） or fully decomposed state（≥80%）. The C/N ratios for the A₀ B₇₀ C₂₅,A_0.5 B₇₀ C₂₂, and A_1.0 B₆₀ C₂₅（13.1, 14.4, and 16.4, respectively） treatments were consistent with the best-fit value（15.0）, and the highest DR value（47.1%） was found in the A_0.5 B₇₀ C₂₂ treatment. The GI value could be inferred from ultraviolet spectral parameter detection, which provided an alternative evaluation method for determining whether the rice straw compost was fully decomposed.Under such controlled experimental conditions, the optimal initial requirements for rice straw decomposition were determined to be a decomposition agent dosage of 0.5%, moisture content of 70%, and initial C/N ratio of 25. Further analysis showed that the decomposition agent dosage had the greatest influence on the DOC content; the moisture content had the greatest influences on the C/N ratio, DR, SUVA₂₈₀, E₂/E₃, and A_226-400 values; and the initial C/N ratio had the greatest influences on the pH and GI values.更多还原