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| Effects of the combined amendment of wheat and huai bean straws on soil organic carbon sequestration |
| Received:January 14, 2018 |
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| KeyWord:huai bean straw;wheat straw;double exponential model;δ13C technology;soil carbon distribution;soil organic carbon sequestration |
| Author Name | Affiliation | E-mail | | ZHU Wen-ling | College of Natural Resources and Environment, Northwest A & F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | | | LI Xiu-shuang | College of Natural Resources and Environment, Northwest A & F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | | | TIAN Xiao-hong | College of Natural Resources and Environment, Northwest A & F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | txhong@hotmail.com | | CHEN Juan | College of Natural Resources and Environment, Northwest A & F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | | | WANG Song | College of Natural Resources and Environment, Northwest A & F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | |
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| Abstract: |
| In order to investigate the effects of incorporation both wheat and leguminous straws on soil organic carbon (SOC) sequestration in dark loessial soils, incubation experiments were conducted in which the δ13C technique combined with the double exponential model was applied, and the C4 soil which had been used for years of maize cultivation was selected. There were four treatments:addition of no straw (CK), addition of wheat straw (W), addition of huai bean straw (L), addition of both wheat straw and huai bean straw (W+L), and each treatment had 6 replications. The results indicated that the cumulative CO2 emissions of the soil and the SOC were significantly increased by W+L, L, and W treatments by 5.63, 2.90, 2.60 folds and 22.3%, 10.7%, 12.5%, respectively, relative to the CK. The W+L treatment markedly increased the microbial biomass carbon (MBC) content and microbial entropy (qMB) by 39.5% and 15.6%, respectively, compared to CK. According to the results of the double exponential model, the addition of crop straws increased the recalcitrant organic carbon pool (C2) and its proportion to the total organic carbon (C2/SOC) under W+L, L, and W treatments by 2.82, 0.756, 1.98 folds and 2.27, 0.569, 1.64 folds, respectively, compared to CK. In addition, compared with W, the W + L treatment could significantly increase the cumulative CO2 emissions of the soil, C2, C2/SOC, MBC content, and qMB, the increments being 84.4%, 28.1%, 23.9%, 25.3% and 14.5%, respectively. At the same time, W+L markedly increased the exogenous newly-formed carbon from crop straws (Cstraw) and its proportion to the total organic carbon (f), and the increases were 86.5% and 79.8%, respectively. Additive effects were observed in the soil accumulation mineralization, SOC, and MBN. In conclusion, although the mixed addition of cereal and leguminous straws facilitate the rate and amount of SOC mineralization, larger amounts of Cstraw are produced by this method compared to mineralization, and the stability of the SOC pool is also increased, which therefore promotes SOC sequestration. The "additive effects" of the two straws play an important role in SOC sequestration. |
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