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| 秸秆碳对不同施肥水平低肥力土壤碳组分的影响 |
| Effect of straw-derived carbon on carbon component of the low fertility soil at different nitrogen application rates |
| 投稿时间：2018-05-12 |
| DOI：10.13254/j.jare.2018.0120 |
| 中文关键词: 秸秆碳，溶解性有机碳，微生物量碳，颗粒有机碳，稳定同位素标记，13C |
| 英文关键词: straw-derived carbon, dissolved organic carbon(DOC), microbial biomass carbon(MBC), particulate organic carbon(POC), stable isotope labeling, 13C |
| 基金项目:国家重点研发计划项目（2017YFD0800600）；浙江省自然科学基金青年基金项目（LQ18D030001）；浙江省重点研发计划项目（2018C02036）；国家小麦产业技术体系项目（CARS-3） |
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| 中文摘要: |
| 为探明不同施肥水平下秸秆碳对低肥力土壤溶解性有机碳（DOC）、微生物量碳（MBC）和颗粒有机碳（POC）含量的影响，采用碳化硅管原位法，向不同施肥水平（0、120、240 kg·hm-2，以纯氮计）的低肥力土壤添加13C标记小麦秸秆，定期取土样测定不同有机碳组分的含量及其δ13C值，并计算秸秆碳在各有机碳库中的转化及贡献比例。研究结果显示，秸秆添加后7 d是快速转化阶段，此后秸秆碳转化渐缓，以向POC转化为主。相较于DOC，秸秆碳更倾向转化为MBC和POC，秸秆添加60 d后的转化比例分别为0.12%~0.38%、4.01%~6.25%和4.74%~9.54%。秸秆添加后，土壤DOC、MBC和POC含量均显著增加，来自于秸秆碳的贡献分别为0.29%~15.01%、13.20%~32.85%和33.62%~59.69%。相较于0、240 kg·hm-2的施氮处理，施氮量为120 kg·hm-2时，秸秆添加能同时大幅提高试验土壤的活性和缓效性有机碳库含量。由此表明，秸秆还田条件下，适量施加氮肥更有利于低肥力土壤的培肥与固碳。 |
| 英文摘要: |
| In order to study the effects of straw C on the contents of dissolved organic carbon (DOC), microbial biomass carbon (MBC)and particulate organic carbon (POC)in low-fertility soil at different nitrogen application rates, 13C-labeled wheat straw was mixed with low fertility soils in the carborundum tube at different nitrogen application rates (0, 120, 240 kg·hm-2, pure nitrogen content). Soils were sampled periodically to analyze carbon component contents and its relative δ13C value. Straw C transformation rate and contribution to soil C pool was also calculated. The results showed that straw C was transformed rapidly within the first 7 days, thereafter the decomposition rate slowed down and was dependent on transformation to POC. Compared with DOC, straw C preferred transforming into MBC and POC, with the transformation rate of 0.12%~0.38%, 4.01%~6.25% and 4.74%~9.54% on 60 d after straw addition, respectively. Soil DOC, MBC, and POC contents were increased significantly by straw addition, with 0.29%~15.01%, 13.20%~32.85% and 33.62%~59.69% of respective carbon derived from straw, respectively. Compared with 0, 240 kg·hm-2 application rates, 120 kg hm-2 could increase the active and slow organic C pool of the experimental soil simultaneously. All results suggest that straw return with moderate nitrogen application is more conducive to both soil fertility improvement and C sequestration of low fertility soil. |
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