耐低温水稻秸秆降解复合菌系筛选构建及田间降解效果研究

Screening and Construction of Low-Temperature Microbial Consortia for Rice Straw Degradation and Field Performance Evaluation

摘要:

为解决东北地区水稻秸秆在低温环境下降解效率低的问题，通过梯度稀释法、刚果红透明圈法、DNS酶活测定及失重率法筛选出高效菌株L3（枯草芽孢杆菌Bacillus subtilis）和P8(酿酒酵母菌Saccharomyces cerevisiae)；以L3和P8为功能菌构建复合菌系，采用室内培养与田间试验相结合的方法，评估其对秸秆降解及土壤改良的效果。结果表明：菌株L3和P8在10℃条件下纤维素酶活性（CMC）分别为10.23 U/mL和9.45 U/mL，滤纸酶活性（FPA）分别达7.64 U/mL和10.96 U/mL，秸秆降解率为10.72%和7.28%；复合菌系b（L3∶P8=1∶2）室内实验中秸秆失重率达47.44%，较单菌处理提升34.85百分点。田间试验结果表明，复合菌2‰施用量显著促进秸秆降解，与对照相比，水稻成熟期降解率提升19.67百分点，土壤有机质、碱解氮、有效磷、速效钾含量分别增加5.88%、1.76%、3.89%和1.65%，水稻苗期株高、鲜重及分蘖数增幅达15.20%~29.84%，产量增加5.18%。研究表明，复合菌系b可突破低温限制，高效降解秸秆、改良土壤并提升作物产量，为寒地农业可持续发展提供关键技术支撑。

Abstract:

To address the bottleneck of low decomposition efficiency of rice straw in cold environments in northern China. Efficiency strains L3 (Bacillus subtilis) and P8 (Saccharomyces cerevisiae) were screened using gradient dilution, Congo red transparent circle method, DNS enzymatic activity assay, and weight loss rate analysis; A composite microbial system was constructed using L3 and P8 as functional strains. Through combined laboratory and field experiments, its effectiveness in straw degradation and soil improvement was evaluated. Results demonstrated that strains L3 and P8 exhibited outstanding performance, showing CMCase and FPA activities of 10.23 U/mL, 9.45 U/mL and 7.64 U/mL, 10.96 U/mL respectively, achieving degradation rates of 10.72% and 7.28% at 10 ℃. Among three constructed consortia, Consortium b (1∶2) showed optimal degradation efficiency with 47.44% straw weight loss, representing 34.85 percentage-point improvement over single-strain treatments. The results of field experiments showed that the application rate of composite bacteria at 2‰ significantly promoted straw decomposition. The degradation rate of rice at maturity was 55.12%, an increase of 19.67 percentage points compared to the control. The content of soil organic matter, alkaline nitrogen, available phosphorus, and available potassium increased by 5.88%, 1.76%, 3.89%, and 1.65% respectively. The plant height, fresh weight, and tiller number of rice seedlings increased by 15.20%-29.84%, and the yield increased by 5.18%. This study demonstrated that composite microbial consortium b can overcome low-temperature limitations to efficiently decompose crop straw, improve soil quality and enhance crop yield, providing critical technological foundations for sustainable agricultural development in cold regions.