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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.
The North China Plain is an important grain production base in China and the soil C and N levels play a direct role in the soil fertility and grain production in the region. Through long-term experiment, the effects of natural recovery (F), tillage with tillage (N) Soil organic carbon (SOC), total organic carbon (SIC), total carbon (TN), total nitrogen (TN) and total nitrogen (TN) and total nitrogen The results showed that soil organic carbon storage of N, S and TS were decreased by 21.6%, 12.3% and 3.4%, respectively, compared with F in 0-20 cm soil layer, while the change of soil inorganic carbon storage was insignificant. ~ 40 cm soil layer, soil organic carbon storage did not change significantly, while the soil inorganic carbon storage in three farmland treatments increased by 4.1% (N), 7.3% (S) and 5.0% (TS), and inorganic carbon increased The contribution of secondary carbonate was only 97% -261% of farmland soil PIC.Compared with natural restoration, the δ15N, δ13CSIC, δ13CSOC and δ13CSOC of farmland soil were significantly different, while the soil layer of 20-40 cm δ15N and δ13CSIC are low and δ13CSOC is high.The primary carbonates in farmland soil are mainly decomposed in this area, and the soil-crop system increases CO2 content The formation of secondary carbonate and the straw return to field are the effective measures for restoring the reduction of soil carbon stocks in farmland cultivation.For the North China Plain, the future should be strengthened about the effects of straw returning and tillage practices on soil organic carbon and inorganic carbon Studies require more long-term observations of carbon conversion and variation in soils below the surface layer.