Rice-wheat rotation and poplar afforestation are two typical land use types in the coastal reclaimed flatlands of eastern China. This study investigated two rice-wheat rotation lands （one reclaimed from 1995 to 2004 ...Rice-wheat rotation and poplar afforestation are two typical land use types in the coastal reclaimed flatlands of eastern China. This study investigated two rice-wheat rotation lands （one reclaimed from 1995 to 2004 and cultivated since 2005, RW1, and the other reclaimed from 1975 to 1995 and cultivated since 1996, RW2） and a poplar woodland （reclaimed from 1995 to 2004 and planted in 2004, PWl） to determine the effects of land use types and years of cultivation on soil microbial biomass and mineralizable carbon （C） in this coastal salt-affected region. The results showed that the soil in PWl remained highly salinized, whereas desalinization was observed in RWl. The total organic C （TOC） in the top soil of PWl and RW1 did not show significant differences, whereas at a soil depth of 20-30 cm, the TOC of RWl was approximately 40%-67% higher than that of PWl. The TOC of 0-30-cm soil in RW2 was approximately 37% higher than that in RW1. Microbial biomass C （MBC） and mineralizable C （MNC） exhibited the trend of RW2 〉 RWl 〉 PWl. Sufficient nutrition with more abundant C substrates resulted in higher MBC and MNC, and soil respiration rates were negatively correlated with C/N in RWl and RW2. Nutrient deficiency and high salinity played key roles in limiting MBC in PWl. These suggested that rice-wheat rotation was more beneficial than poplar afforestation for C accumulation and microbial biomass growth in the coastal salt-affected soils.展开更多
基金supported financially by the National Key Research and Development Program of China (Nos.2016YFD0200303, 2016YFC0501309, and 2016YFC0501201)the Project of the Science and Technology Service (STS) Network Initiative, Chinese Academy of Sciences (No.KFJ-SW-STS-141-2)+3 种基金the Independent Innovation Project of Jiangsu Agricultural Science & Technology, China (No.CX(15)1005)the Key Research and Development Program of Jiangsu Province, China (No.BE2015337)the National Key Technology R&D Program of China (No.2015BAD-01B03-4)the National Natural Science Foundation of China (No.41171181)
文摘Rice-wheat rotation and poplar afforestation are two typical land use types in the coastal reclaimed flatlands of eastern China. This study investigated two rice-wheat rotation lands （one reclaimed from 1995 to 2004 and cultivated since 2005, RW1, and the other reclaimed from 1975 to 1995 and cultivated since 1996, RW2） and a poplar woodland （reclaimed from 1995 to 2004 and planted in 2004, PWl） to determine the effects of land use types and years of cultivation on soil microbial biomass and mineralizable carbon （C） in this coastal salt-affected region. The results showed that the soil in PWl remained highly salinized, whereas desalinization was observed in RWl. The total organic C （TOC） in the top soil of PWl and RW1 did not show significant differences, whereas at a soil depth of 20-30 cm, the TOC of RWl was approximately 40%-67% higher than that of PWl. The TOC of 0-30-cm soil in RW2 was approximately 37% higher than that in RW1. Microbial biomass C （MBC） and mineralizable C （MNC） exhibited the trend of RW2 〉 RWl 〉 PWl. Sufficient nutrition with more abundant C substrates resulted in higher MBC and MNC, and soil respiration rates were negatively correlated with C/N in RWl and RW2. Nutrient deficiency and high salinity played key roles in limiting MBC in PWl. These suggested that rice-wheat rotation was more beneficial than poplar afforestation for C accumulation and microbial biomass growth in the coastal salt-affected soils.
