红壤丘陵区典型农田土壤秸秆还田后纤维素降解特征及其影响因素  

Characteristics of cellulose degradation after straw return and its influence factors in arable lands in red soil hilly region

作　　者：董明哲[1,2] 陈香碧[1,3] 冯书珍[1,2] 尹春梅[1,4] 苏以荣[1,3] 

机构地区：[1]中国科学院亚热带农业生态研究所亚热带农业生态重点实验室,长沙410125 [2]中国科学院大学,北京100049 [3]中国科学院环江喀斯特农业生态试验站,广西环江547100 [4]中国科学院桃源农业生态试验站,湖南桃源415700

出　　处：《生态学杂志》2016年第7期1834-1841,共8页Chinese Journal of Ecology

基　　金：国家科技支撑计划项目(2012BAD05B06);国家自然科学基金项目(41301273);中国科学院西部之光人才培养计划"西部博士项目"资助

摘　　要：以亚热带红壤丘陵区典型旱地和水旱轮作长期定位试验地为研究对象,以单施化肥(NPK)为对照,研究长期秸秆还田配施化肥(NPKS)后农田土壤中纤维素的积累效应及其周年降解特征,并从纤维素降解的关键酶活性、土壤基本性质和气候环境阐明影响农田土壤中纤维素降解的主要因子。结果表明:两种土地利用方式下,长期(13年)NPKS处理后土壤中纤维素积累并不显著;周年变化来看,添加NPKS后旱地和水旱轮作地土壤中纤维素含量分别在施肥后6和3个月内迅速降至施肥前水平,表现为水旱轮作地土壤中纤维素降解速率显著高于旱地;水旱轮作地中纤维二糖水解酶(CBH)及β-葡萄糖苷酶(βG)活性的增量在添加NPKS后均显著高于旱地,说明水旱轮作地中纤维素酶活性对秸秆还田的响应更强;两种土地利用方式下,长期施肥后纤维素占土壤有机质的比例下降,说明纤维素并不是亚热带红壤丘陵区农田土壤有机碳库积累重要的直接组分。相关分析和回归分析结果表明,β-葡萄糖苷酶、土壤微生物生物量碳、碱解氮是影响纤维素降解的主要因子。未来可通过调整施肥、土地利用方式来调控亚热带红壤丘陵区农田土壤有机碳库及其组分的转化过程。Based on long-term field fertilization experiments in subtropical upland and upland-paddy rotation land, the characteristics of long-term accumulation and annual degradation after long-term chemical fertilization （nitrogen, phosphorus, and potassium） combined with crop straw （NPKS） were compared with those of chemical fertilization （NPK）. Meanwhile, the main influencing factors on cellulose degradation were clarified from the sights of key enzyme activities, soil properties and climate factors. The results showed that cellulose was not significantly accumulated after long-term （13 years） NPKS fertilization for both lands. After application of NKPS fertilization, the cellulose content was decreased to its initial level after 3 months and 6 months in rotation land and upland respectively, with the faster degradation rate in the former land. After NPKS fertilization, the increment of the activities of cellulolytic enzymes （（cellobiohydrolase （CBH） and β-glucosidase （βG）） were significantly higher in rotation land than in upland, implying a stronger response of cellulolytic enzyme in rotation land to NPKS fertilization. Besides, the proportions of cellulose in soil organic matter （CEL/SOM） were significantly decreased after long-term fertilization in both lands, suggesting that cellulose was not the key component contributing to the accumulation of SOM in subtropical agricultural lands. Correlation analysis and stepwise regression analysis demonstrated that the β-glucosidase, soil microbial biomass carbon and available nitrogen were the key factors determining cellulose degradation. In the future, fertilization and land-use type could be useful strategies to regulate the transformation of soil organic matter and its components in arable lands in red soil hilly region.

关 键 词：秸秆还田 纤维素 降解 旱地 水旱轮作地 

分 类 号：S141.4[农业科学—肥料学]