保护性耕作对农田土壤有机碳库的影响

农田土壤有机碳库是陆地生态系统碳库的重要组成部分,对维持全球碳平衡具有重要意义。有机碳库的储量除了受气候和环境因素的影响外,还受农业耕作措施的影响。综述了保护性耕作对土壤有机碳库的影响,并从碳输入、碳分解和碳固持3个方面讨论了保护性耕作影响有机碳库的途径。大量实验结果表明,保护性耕作在表层土壤中能提高作物根系生物量1.0%~142.9%;增加土壤微生物的生物量2.2%~140%。免耕还显著降低土壤的呼吸强度,在0.9%~72.6%之间,从而减少碳的损失。免耕还提高了土壤团聚体数量,从而有利于有机碳在土壤中的固持。今后的研究应该在如下几方面加强：（1）加强区域性对比研究;（2）加强长期定位研究;（3）加强对固碳机理的研究;（4）建立模型加强对多种因子综合效应的研究。

Effects of conversation tillage on soil organic carbon pool

Farmland soil organic carbon,as an important component of terrestrial carbon poo1,plays a crucial role in global carbon balance.It is influenced by climate,environmental factors and farming practices.This paper reviewed the effects of conservation tillage on it,and discussed the main routes of this influence through carbon input,decomposition and sequestration.According to literature records,under conservation tillage condition,crop root biomass in top soil increased 1.0%-142.9%,and soil microbial biomass increased 2.2%-140%.No-Tillage significantly reduced soil respiration rate from 0.9%-72.6%,thereby reduced the loss of carbon in soil.No-tillage also increased the amount and size of soil aggregates,to facilitate organic carbon sequestration in soil.The following aspects should be strengthened in the future research：（1）strengthening contrast research among with regional;（2） strengthening the long-term located research;（3） to strengthen the mechanism of carbon sequestration research;（4） establishing the model of multi-factor to strengthen the study on comprehensive effect.