摘要
作物光合碳是“大气-植物-土壤”碳循环的重要组成部分，是农田土壤有机碳的重要来源，然而其在土壤碳库中的矿化和转化动态尚不清楚．应用室内模拟培养实验，研究水稻收获后输入土壤的光合同化碳在土壤碳库中的矿化及其转化特征．结果表明，100d的培养期内，原有有机碳的平均矿化速率在4．44～17．8μg·（g·d）^-1之间，而光合碳（新碳）的矿化速率则在0．15～1．51μg·（g·d）^-1之间．光合同化碳的输入对土壤活性碳库（DOC、MBC）的转化产生显著影响，在培养期内，^14C—DOC的转化量为1．89～5．32mg·kg^-1，转化速率的变化幅度为0．18～0．34mg·（kg·d）^-1，原有DOC则在61．13～90．65mg·kg^-1，减少幅度为4．10～5．48mg·（kg·d）^-1；^14C—MBC和原有MBC的转化量分别为10．92～44．11mg·kg^-1和463．31～1153．46mg·kg^-1，转化速率变化幅度分别为0．80～2．87mg·（kg·d）^-1和41．60～74．46mg·（kg·d）^-1，说明水稻光合碳的输入对MBC的周转要大于DOC的周转．而且，与原有有机碳相比，输入的“新碳”易被微生物矿化分解，100d的培养期内，有13．5％～20．2％的新碳被矿化分解，而仅2．2％-3．7％的原有有机碳被矿化分解，光合同化碳的输入对维持稻田土壤的碳汇功能具有重要作用．
Photosynthesized carbon is an important part in C cycling of ＂atmosphere-plant-soil＂ and is the source of soil organic carbon （SOC）, but its mineralization and transformation dynamics in paddy soils remains still unclear. Therefore, a batch incubation experiment was conducted to investigate the mineralization and transformation of rice photosynthesized carbon in paddy soils after rice harvest. The results showed that the mineralization rate of native SOC ranged from 4.44 to 17.8μg·（g·d）^-1, while that of photosynthesized carbon （new carbon） was 0. 15- 1.51 μg·（g·d）^-1 during the course of 100-day-incubation span. Rice photosynthesized carbon input significantly influenced the soil active carbon （DOC, MBC） transformation. During the incubation period （ 100 d） , the amount of 14C-DOC transformation ranged from 1.89 to 5.32 mg· kg^-1 ,and that of native DOC varied from 61. 13 to 90. 65 mg· kg^-1, with the transformation rates ranged from 0.18 to 0.34 mg·（kg·d）^-1 and from 4. 10 to 5.48 mg·（kg·d）^-1, respectively. However, the 14C-MBC and native original MBC were 10.92-44. 11 mg· kg^-1 and 463.31-1 153.46 mg· kg^-1 respectively, and their transformation rates were 0.80-2. 87, 41, 60-74. 46 mg·（kg·d）^-1,respectively. It suggested that the turnover of MBC was greater than that of DOC. Furthermore, ＂new carbon＂ was easier to be mineralized and decomposed than native SOC. The mineralized portion in ＂new carbon＂ was 13.5%-20. 2%, whereas that in native SOC was only 2.2%-3.7%. Therefore, we concluded that the incorporation of rice photosynthesized carbon was vital to maintain the soil carbon sink for paddy soils.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2014年第1期233-239,共7页
Environmental Science
基金
中国科学院
国家外国专家局创新团队国际合作伙伴计划项目(KZCX2-YW-T07
20100491005-8)
国家自然科学基金项目(41090283
40901124)
湖南省自然科学基金项目(11JJ4030)
中国科学院海外特聘研究员项目(2009Z2-10)
关键词
光合同化碳
水稻土
矿化
转化
土壤微生物生物量碳
土壤可溶性有机碳
photosynthesized carbon
paddy soil
mineralization
transformation
soil microbial biomass carbon
soil dissolved carbon
