| 紫色土丘陵区退耕还林对坡地土壤碳氮空间分布的影响 |
| 摘要点击 841 全文点击 239 投稿时间：2023-09-15 修订日期：2023-10-19 |
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| 中文关键词 紫色土 退耕还林 坡位 土壤氮（N） 土壤碳（C） 空间分布 |
| 英文关键词 purple soil “Grain for Green” slope position soil nitrogen （N） soil carbon （C） spatial distribution |
| 作者 | 单位 | E-mail | | 李子阳 | 中国科学院水利部成都山地灾害与环境研究所, 山地表生过程与生态调控重点实验室, 成都 610041
中国科学院大学, 北京 100049 | liziyang18@mails.ucas.ac.cn | | 刘伟 | 四川省泸州市叙永县农业农村局, 泸州 646400 | | | 李春培 | 中国科学院水利部成都山地灾害与环境研究所, 山地表生过程与生态调控重点实验室, 成都 610041
中国科学院大学, 北京 100049 | | | 朱波 | 中国科学院水利部成都山地灾害与环境研究所, 山地表生过程与生态调控重点实验室, 成都 610041 | | | 周明华 | 中国科学院水利部成都山地灾害与环境研究所, 山地表生过程与生态调控重点实验室, 成都 610041 | mhuazhou@imde.ac.cn |
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| 中文摘要 |
| 为了弥补我国四川盆地紫色土丘陵区退耕还林对坡地土壤碳（C）和氮（N）时空分布影响的研究不足,依托中国科学院盐亭紫色土农业生态试验站在万安小流域建立的长期观测样地,对比分析了约30年历史的退耕林地及其邻近的坡耕地不同坡面位置土壤的C、N形态、含量及其储量. 结果发现,退耕还林后,显著增加了剖面土壤有机碳（SOC）含量及储量（P< 0.05）,其中表层土壤（0~20 cm）SOC储量增加了25.86 t·hm-2,年均SOC储量增加速率为0.89 t·hm-2. 土壤总氮（TN）含量虽略有增加,但仅限于0~20 cm土层. 退耕林地与坡耕地相比,速效C、N养分如,土壤硝态氮（NO3--N）、铵态氮（NH4+-N）和可溶性有机碳（DOC）含量在整个土壤剖面（0~70 cm）的差异性基本不显著（P> 0.05）. 此外,研究还发现空间位置对坡耕地土壤TN、SOC、NO3--N、NH4+-N和DOC含量均有显著影响（P< 0.05）；土壤TN和SOC含量沿坡面的变化趋势大小为：下坡位>上坡位>中坡位,而土壤NO3--N、NH4+-N和DOC含量沿坡面的变化趋势大小则为：上坡位<中坡位<下坡位. 退耕林地土壤仅DOC含量受坡位的显著影响,并沿坡面向下呈增加趋势. 结果表明,在评估紫色土丘陵区土地利用变化对土壤碳氮储量的影响时,不能忽视地形等因素的影响. |
| 英文摘要 |
| In order to remedy the lack of research on the effect of “Grain for Green” on soil carbon （C） and nitrogen （N） distribution on slope soil in purple hilly areas of Sichuan Basin, China, a study was conducted on a long-term observation site established in the Wanan small watershed of Yanting Agro-ecological Experimental Station of Purple Soil, Chinese Academy of Sciences. The morphology, content, and storage of C and N in soil at different slope positions of farmland and the artificial forests in rehabilitated land with a history of approximately 30 years were compared. Our results showed that “Grain for Green” significantly increased soil organic carbon （SOC） content and SOC stock in all soil layers. The SOC stock of the surface layer （0-20 cm） increased by 25.86 t·hm-2, and the annual SOC stocks ratio was 0.89 t·hm-2. Soil total nitrogen （TN） content increased slightly but only in the 0-20 cm soil layer. Compared with those in sloping farmland, the differences in available C and N nutrients such as soil nitrate N （NO3--N）, ammonia N （NH4+-N）, and dissolved organic C （DOC） in the whole soil profile （0-70 cm） were basically not significant （P > 0.05）. In addition, our research also found that slope position had significant effects on the contents of TN, SOC, NO3--N, NH4+-N, and DOC in farmland soil （P< 0.05）. The variation trend of soil NO3--N, NH4+-N, and DOC contents along the slope was as follows： upper slope < middle slope < lower slope, whereas the soil TN and SOC contents were highest in the lower slope, followed by the upper slope and middle slope. The position of the slope had a significant impact only on DOC content in forest soil, which increased along the slope. This research indicated that when evaluating the impact of land use changes on soil C and N stocks in the purple soil hilly region, the influence of topographic factors cannot be ignored. |
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