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寧夏荒漠草原沙漠化過程中土壤粒徑分形特征

發(fā)布時(shí)間:2018-09-19 12:16
【摘要】:研究寧夏荒漠草原沙漠化過程中土壤性狀、土壤粒徑分形維數(shù)的變化特征,以及分形維數(shù)與土壤性狀的關(guān)系.結(jié)果表明:草地沙漠化對土壤分形維數(shù)(D)影響顯著,D值為1.69~2.62.除在10~20 cm土層出現(xiàn)較小波動(dòng)外,隨著沙漠化程度加劇,0~30 cm土層D值整體呈減小趨勢.在荒漠草原沙漠化過程中,荒漠草地D值最大,黏粒和粉粒體積百分含量最高,極細(xì)砂粒和細(xì)砂粒體積百分含量最低;流動(dòng)沙地D值最小,黏粒和粉粒體積百分含量最小,極細(xì)砂粒和細(xì)砂粒體積百分含量最高.D與50μm和50μm粒徑的土壤顆粒存在顯著正相關(guān)和負(fù)相關(guān),表明50μm粒徑是決定草地沙漠化過程中土壤分形維數(shù)與土壤粒徑關(guān)系的臨界粒徑.隨著荒漠草原沙漠化加劇,土壤有機(jī)質(zhì)和全氮含量逐漸降低,土壤容重逐漸升高,固定沙地至半固定沙地是荒漠草原沙漠化的質(zhì)變過程,其中土壤粘粒體積百分含量、粉粒體積百分含量、土壤有機(jī)質(zhì)含量、土壤全氮含量驟減,極細(xì)砂粒體積百分含量、細(xì)砂粒體積百分含量和土壤容重驟增.分形維數(shù)與土壤有機(jī)質(zhì)、土壤全氮和土壤容重顯著相關(guān),固定沙地與半固定沙地分形維數(shù)的臨界值為2.58,因此分形維數(shù)2.58可作為荒漠草原沙漠化的退化指標(biāo).
[Abstract]:The change characteristics of soil characters, the fractal dimension of soil particle size and the relationship between fractal dimension and soil character in desert steppe of Ningxia were studied. The results showed that the significant effect of desertification on soil fractal dimension (D) was 1.69 ~ 2.62. Except for the small fluctuation in 10 ~ 20 cm soil layer, the D value of 0 ~ 30 cm soil layer decreased with the increase of desertification degree. In the process of desert grassland desertification, the D value of desert grassland is the largest, the volume percent content of clay and silt is the highest, the volume percent content of extremely fine sand and fine sand is the lowest, the D value of flowing sandy land is the least, and the content of clay and silt is the smallest. There was significant positive correlation and negative correlation between the soil particle size of 50 渭 m and 50 渭 m, indicating that the particle size of 50 渭 m was the critical particle size in determining the relationship between soil fractal dimension and soil particle size in the process of grassland desertification. With the increasing desertification of desert steppe, the content of soil organic matter and total nitrogen decreased gradually, and the bulk density of soil gradually increased. It is the qualitative change process of desert steppe desertification from fixed sandy land to semi-fixed sandy land, among which the content of soil clay is percent. The content of silt volume, soil organic matter, soil total nitrogen content, very fine sand volume percent content, fine sand volume percentage content and soil bulk density increased sharply. The fractal dimension was significantly correlated with soil organic matter, soil total nitrogen and soil bulk density. The critical value of fractal dimension between fixed and semi-fixed sandy land was 2.58. Therefore, fractal dimension 2.58 could be used as an index of desertification degradation in desert steppe.
【作者單位】: 寧夏大學(xué)西北土地退化與生態(tài)恢復(fù)省部共建國家重點(diǎn)實(shí)驗(yàn)室培育基地/西北退化生態(tài)系統(tǒng)恢復(fù)與重建教育部重點(diǎn)實(shí)驗(yàn)室;
【基金】:寧夏高等學(xué)?茖W(xué)研究項(xiàng)目(NGY2017006)資助~~
【分類號(hào)】:S812.2

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