华北平原不同农田管理措施对于土壤碳库的影响

发布时间：2018-08-26 20:06

【摘要】：华北平原是我国重要的粮食生产基地,土壤碳氮水平直接作用于区域的土壤肥力和粮食生产.通过长期定位实验,研究了包括自然恢复(F)、清茬翻耕(N)、秸秆还田免耕(S)和秸秆还田翻耕(TS)这4个处理下土壤有机碳(SOC)、无机碳(SIC)、全碳(TS)、全氮(TN)含量和储量以及13C和15N分布状况.结果表明,与F相比,在0~20 cm土层,N、S和TS的土壤有机碳储量分别降低21.6%、12.3%和3.4%,土壤无机碳储量变化不显著.在20~40 cm土层,土壤有机碳储量变化不显著,而3个农田耕作处理的土壤无机碳储量较F分别增加4.1%(N)、7.3%(S)和5.0%(TS),无机碳增加主要是次生碳酸盐的贡献,农田土壤PIC增加了97%~261%.与自然恢复地相比,农田土壤表层δ15N、δ13CSIC、δ13CSOC偏高且δ13CSOC达显著差异,20~40 cm土层δ15N、δ13CSIC偏低而δ13CSOC偏高.该地区农田土壤中原生碳酸盐以分解作用为主,土壤-作物系统通过增加CO_2含量促进次生碳酸盐的形成,秸秆还田是恢复农田耕作引起土壤碳库储存下降的有效措施.对于华北平原,今后应加强关于秸秆还田和耕作措施对土壤有机碳和无机碳影响的综合研究,对于表层以下层次土壤的碳转化和变化规律需要更多的长期观测.
[Abstract]:North China Plain is an important grain production base in China. Soil carbon and nitrogen level directly affect the soil fertility and grain production in the region. The content and storage of total organic carbon (SOC),) inorganic carbon (SIC),) total carbon (TS),) total nitrogen (TN) (TN) and the distribution of 13C and 15N of soil organic carbon (SOC),) and inorganic carbon (SIC),) in soil under four treatments including natural recovery (F), stubble cleaning (N), straw no-tillage (S) and straw returning (TS) were studied. The results showed that, compared with F, the soil organic carbon storage in 0 ~ 20 cm soil layer was decreased by 21.6% and 3.4%, respectively, and there was no significant change in soil inorganic carbon storage. In 20 ~ 40 cm soil layer, the change of soil organic carbon storage was not significant, but the increase of inorganic carbon storage of three farmland tillage treatments was 4.1% (N) + 7.3% (S) and 5.0% (TS), inorganic carbon, respectively. The contribution of secondary carbonate was the main factor, and the increase of PIC in farmland soil was 97% ~ 261%. Compared with the natural restoration land, the surface layer 未 15N, 未 13CSIC, 未 13CSOC of farmland soil was higher and 未 13CSOC was significantly different. 未 15N, 未 13CSIC and 未 13CSOC were lower and higher than those in the soil layer of 2040 cm. The primary carbonate in farmland soil in this area is mainly decomposed. The soil-crop system promotes the formation of secondary carbonate by increasing the content of CO_2. Returning straw to the field is an effective measure to restore the soil carbon storage and decrease caused by farmland tillage. For North China Plain, the comprehensive study on the effects of straw returning and tillage measures on soil organic and inorganic carbon should be strengthened in the future.
【作者单位】：中国农业大学资源与环境学院;
【基金】：国家科技支撑计划项目(2012BAD14B01) 国家自然科学基金项目(31261140367,31370527)
【分类号】：S153.6

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