摘要
稻田土壤有机碳是甲烷排放的关键底物之一,不同研究者由于采取的有机碳研究方法不同而得出稻田甲烷排放与土壤有机碳关系的结论不一。为明确影响稻田甲烷排放的土壤有机碳组分,设计了稻田施用不同外源有机碳(稻草还田、鸡粪和猪粪)的田间试验,对稻田甲烷排放和土壤有机碳组分的动态变化及其关联性进行监测和分析。结果表明,猪粪处理的甲烷排放与化肥处理无显著差异,而鸡粪和稻草2个处理的甲烷排放分别比化肥增加1.67倍(P<0.05),2.69倍(P<0.05);甲烷排放量与土壤易氧化有机碳含量显示相同顺序:稻草>鸡粪>猪粪>化肥;通径分析表明,土壤易氧化有机碳组分1(被33 mmol/LKMnO4氧化的有机碳)与甲烷排放直接相关,其他有机碳组分仅通过组分1间接作用于水稻生育后期甲烷排放,且排放量较低。由此推断,易氧化有机碳组分1是甲烷排放的主要底物,通过有效措施降低肥源中易氧化态有机碳组分1是减排甲烷的关键技术之一。
Application of organic manure increases methane emissions from rice paddy fields by increasing soil organic matter. Soil organic carbon is one of the key substrates that affect methane emission from paddy soils. Different methods of researching organic carbon have been used by different researchers which have led to different conclusions regarding correlations between organic carbon and methane emission from paddy soils. To define how methane emission is influenced by fractions of soil organic carbon, a paddy field experiment with application of different exogenous organic carbon （rice straw＋chemical fertilizer, chicken manure＋chemical fertilizer and pig manure＋chemical fertilizer） was used to monitor and analyze methane emission, changes in organic carbon fractions and their correlation. A week after application of organic manure, rice straw ＋chemical fertilizer （RS） and chicken manure＋chemical fertilizer （CM） showed emission peaks of 221.6 and 128.2 mg·m-2·h-1, respectively. The methane emission was mainly concentrated before the heading stage. The amount of methane emitted in the growing season following the chemical fertilizer （CF） treatment was 296.0 kg/hm2 and following the pig manure＋chemical fertilizer （PM）, CM, and RS treatments were 340.7, 493.6 and 794.8 kg/hm2, respectively. There was no significant difference in methane emissions between the PM and CF treatments, while emissions from the CM and RS treatments were 1.67 times （P 〈 0.05） and 2.69 times （P 〈 0.05） higher than from the CF treatment, respectively. Amounts of methane emission and the content of oxidizable organic carbon in the paddy soil followed the same order： RS 〉 CM 〉 PM 〉 CF and no fertilizers. The content of organic C fractions followed the order： fraction 1 （organic C oxidizable by 33 mmol/L KMnO4） 〉 fraction 2 （the difference in C oxidizable by 167 mmol/L and that by 33 mmol/L KMnO4） 〉 fraction 3 （the difference in C oxidizable by 333 mmol/L and that by 167 mmol/L
出处
《生态学报》
CAS
CSCD
北大核心
2013年第15期4599-4607,共9页
Acta Ecologica Sinica
基金
国家科技支撑计划(2013BAD11B02)
