【摘要】：過度放牧是科爾沁沙地退化的主要原因,禁牧圍封可以有效地控制牲畜對植被-土壤系統(tǒng)的破壞,促進退化生態(tài)系統(tǒng)的有效恢復。以過度放牧后的沙漠化草地為對象,調查了禁牧圍封13年后沙漠化草地土壤理化性質的變化特征,并分析了圍封對土壤固碳潛力的影響。結果表明:(1)沙漠化草地圍封13年后,土壤砂粒含量減少、粉粒和黏粒含量增加,且粉粒增加最為明顯,平均含量增加123%;土壤容重在不同土壤深度均呈下降趨勢。(2)圍封后土壤有機質、全氮、速效氮和速效鉀含量呈增加趨勢,分別增加了102%、97%、123%和24%,但土壤有效磷和緩效鉀呈減少趨勢;土壤pH顯著升高,陽離子交換量呈現(xiàn)增加趨勢。(3)除土壤有效鐵外,其余有效微量元素包括有效銅、有效錳和有效鋅平均含量均呈增加趨勢,分別增加44%、30%和82%。(4)土壤有機質與pH值、陽離子交換量、全氮、速效氮、速效鉀、有效銅、有效錳、有效鋅含量呈顯著正相關關系。(5)沙漠化草地圍封13年后,100cm深度土壤有機碳儲量增加393.45 g·m~(-2),碳截存速率為30.27 g C·m~(-2)·a-1。對于因持續(xù)過度放牧所導致的嚴重退化草地,禁牧圍封可有效促進土壤有機質、養(yǎng)分和微量元素的增加,影響土壤質地及固碳潛力等的變化,但嚴重退化沙漠化草地的恢復需要一個長期的過程,土壤有機碳儲量要恢復到科爾沁非沙漠化草地水平至少需要百年的時間尺度。
[Abstract]:Overgrazing is the main cause of degradation in Horqin sandy land. Forbidding grazing enclosure can effectively control livestock damage to vegetation-soil system and promote the effective restoration of degraded ecosystem. The changes of soil physical and chemical properties of desertification grassland after 13 years of forbidding grazing were investigated, and the effects of enclosure on soil carbon sequestration potential were analyzed. The results are as follows: (1) after 13 years of closure of desertification grassland, the content of sand and clay in soil decreased, and the content of silt and clay increased most obviously. The average content of organic matter, total nitrogen, available nitrogen and available potassium increased by 102% and 24%, respectively, but the available phosphorus and slow available potassium decreased. (3) except for available iron, the average contents of available trace elements, including available copper, available manganese and available zinc, increased by 44% and 82%, respectively. (4) soil organic matter and pH value. Cationic exchange capacity, total nitrogen, available potassium, available copper, available manganese and available zinc were positively correlated. (5) the soil organic carbon storage increased by 393.45 g m-2 and the carbon sequestration rate was 30.27 g cm ~ (-2) a ~ (-1). For the severely degraded grassland caused by continuous overgrazing, forbidding grazing enclosure can effectively promote the increase of soil organic matter, nutrients and trace elements, and affect the changes of soil texture and carbon sequestration potential, etc. However, the restoration of degraded desertification grassland needs a long-term process, and it takes at least a hundred years for the soil organic carbon reserves to recover to Horqin non-desertification grassland level.
【作者單位】： 中國科學院西北生態(tài)環(huán)境資源研究院奈曼沙漠化研究站;中國科學院大學;華東師范大學生態(tài)與環(huán)境科學學院/上海市城市化生態(tài)過程與生態(tài)恢復重點實驗室;
【基金】：國家自然科學基金項目(31640012,41271007) 中國科學院“百人計劃”項目(Y551821)
【分類號】：S812

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