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| Soil CH4 emission and its relationship with organic carbon fraction under different irrigation methods and nitrogen rates |
| Received:December 09, 2016 |
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| KeyWord:CH4 emission;“Thin-shallow-wet-dry” irrigation;alternate drying and wetting irrigation;nitrogen rate |
| Author Name | Affiliation | E-mail | | WANG Kai | College of Agriculture, Guangxi University, Nanning 530004, China
Guangxi Academician Work Station of The New Technology of Water-saving Agriculture in Karst Region, Nanning 530004, China
Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Nanning 530005, China | | | LI Fu-sheng | College of Agriculture, Guangxi University, Nanning 530004, China
Guangxi Academician Work Station of The New Technology of Water-saving Agriculture in Karst Region, Nanning 530004, China
Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Nanning 530005, China | lpfu6@163.com | | FANG Ze-tao | College of Agriculture, Guangxi University, Nanning 530004, China
Guangxi Academician Work Station of The New Technology of Water-saving Agriculture in Karst Region, Nanning 530004, China
Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Nanning 530005, China | | | DONG Yan-fang | College of Agriculture, Guangxi University, Nanning 530004, China
Guangxi Academician Work Station of The New Technology of Water-saving Agriculture in Karst Region, Nanning 530004, China
Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Nanning 530005, China | | | LIU Jing-wen | College of Agriculture, Guangxi University, Nanning 530004, China
Guangxi Academician Work Station of The New Technology of Water-saving Agriculture in Karst Region, Nanning 530004, China
Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Nanning 530005, China | | | HUANG Zhong-hua | Nanning Irrigation Experimental Station, Nanning 530001, China | | | LUO Wei-gang | Nanning Irrigation Experimental Station, Nanning 530001, China | |
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| Abstract: |
| The readily decomposed organic matter in the paddy ecosystem increase soil methane (CH4) emission under anaerobic environment, while methane oxidizing bacteria (MOB) oxidation of methane reduces soil CH4 emission under better aeration environment. Field experiments with different irrigation methods and nitrogen (N) rates were carried out to measure the contents of organic carbon (SOC) and easily oxidized organic carbon (LOC), microbial biomass carbon (MBC) and the number of MOB at different growth stages, and CH4 emission fluxes from paddy field during the growth stage, and then the relationships between the CH4 emission flux and the contents of SOC and LOC, MBC and MOB in soils at the sampling days were analyzed, so as to obtain the rational irrigation mode and N rate for CH4 reduction. Two-season field experiments included three irrigation methods, i.e. conventional irrigation (C), “thin-shallow-wet-dry” irrigation (T) and alternate drying and wetting irrigation (D), and two N rates (N1 120 kg·hm-2 and N2 150 kg·hm-2). Results show that D mode had lower SOC content at the booting stage of late rice and tillering stage of early rice under N1, and D mode had the highest SOC content at the four growth stages of early rice and late rice under N2. When planting early rice and late rice, D mode had lower LOC content, and C mode had lower MOB and higher MBC. The contents of SOC, LOC, MBC and MOB in N2 were higher than those of N1. Accumulative CH4 emissions over the whole growth stage of early rice or late rice and the total of both seasons in D mode were significantly lower than those of T and C modes, but these indices in N2 were higher than those of N1. CH4 emission flux was directly influenced by the soil MOB, LOC and MBC and indirectly affected by the SOC. CH4 emission from paddy soil was the lowest under alternate drying and wetting irrigation and N rate of 120 kg·hm-2. |
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