| 华北平原不同农田管理措施对于土壤碳库的影响 |
| 摘要点击 2986 全文点击 858 投稿时间：2016-05-27 修订日期：2016-08-27 |
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| 中文关键词 华北平原 有机碳 无机碳 同位素 秸秆还田 |
| 英文关键词 North China Plain soil organic carbon soil inorganic carbon natural isotope crop straw incorporation |
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| 中文摘要 |
| 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CO2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. |
| 英文摘要 |
| North China Plain is an important region of grain production.Soil fertility and grain production in this region are significantly influenced by the levels of soil carbon and nitrogen.In order to explore the effects of agricultural practices on the levels of soil carbon and nitrogen,a long-term field experiment was started in 1999 in Quzhou County,Hebei Province.Four treatments,including following nature (F),tillage without straw (N),no tillage with crushed straw incorporation (S),and tillage with crushed straw incorporation (TS),were chosen to collect soil samples at the layers of 0-20 cm and 20-40 cm in 2013.Soil organic carbon (SOC),soil inorganic carbon (SIC),total carbon (TC),total nitrogen (TN),δ13CSOC,δ13CSIC and δ15 N were analyzed.The results indicated that compared with F,SOC stocks of N,S and TS decreased by 21.6%,12.3% and 3.4% in the 0-20 cm soil layer,but the changes of SIC stocks were not significant.In the 20-40 cm soil layer,the changes of the SOC stocks were not significant,but the SIC stocks increased by 4.1%(N),7.3%(S) and 5.0%(TS) compared to F,respectively.Major contribution of SIC increase was the pedogenic inorganic carbonate (PIC),which increased by 97%-261% in the farmland soil.In the soil layer of 0-20 cm,the values of δ15N,δ13CSIC and δ13CSOC in the farmland treatments were higher than those of F,meanwhile,the values of δ13 CSOC were significantly higher than that of F.In the soil layer of 20-40 cm,the values of δ15N and δ13CSIC were lower than those of F,but the value of δ13CSOC showed the opposite trend.In North China Plain,lithogenic inorganic carbonate (LIC) of farmland soil decomposed and PIC increased by the soil-crop system,which provided CO2 for the formation of PIC,and straw returning was an effective agricultural practice to restore the soil carbon decreased by tillage.There should be more long-term monitoring and studies for the impacts of crop straw incorporation and tillage on SOC and SIC,especially for soil in deeper layers. |
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