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为了评价退耕地土壤抗冲性的变化,该文以黄土高塬沟壑区自然退耕农地为研究对象,通过径流小区冲刷法对不同覆盖度塬面退耕地(TAL,table-land abandoned land)和沟头退耕地(GAL,gully-head abandoned land)土壤抗冲性进行了研究。结果表明,1)与对照(Ⅰ)相比,TAL和GAL处理水稳性团聚体、根系密度和根系生物量均显著增加(P<0.05),覆盖度大于0时,崩解速率显著减小44.87%~79.16%和33.79%~70.65%,有机质显著增加70.12%~222.70%和59.20%~194.88%,覆盖度最大时,土壤容重和渗透系数才显著减小和增大。2)TAL处理0覆盖度小区抗冲系数(AS,anti-scouribility)较对照无差异,其余覆盖度则显著增大2.31~7.57倍,GAL处理AS较对照显著增大0.99~7.12倍,覆盖度越大,根系提高土壤抗冲性能的效果越显著。3)TAL和GAL处理AS分别与容重、崩解速率、水稳性团聚体含量、渗透系数均呈极显著指数函数关系,与有机质含量、根系生物量及根系密度均呈极显著线性函数关系。水稳性团聚体是影响塬面和沟头退耕地土壤抗冲性的关键因子。结果可为研究区退耕还林还草工程生态功能评价及水土流失治理提供理论依据。
In order to evaluate the change of soil anti-farmland in the conversion of cultivated land, the paper takes the natural farmland in the gully area of the Loess Plateau as the research object. Through the run-off plot scouring method, TAL (tableland abandoned land) Soil anti-scourability of GAL (gully-head abandoned land) was studied. The results showed that: 1) Compared with the control (I), TAL and GAL treated water-stable aggregates, the root density and root biomass increased significantly (P <0.05). When the coverage was greater than 0, the disintegration rate was significantly decreased From 44.87% to 79.16% and from 33.79% to 70.65%, the contents of organic matter significantly increased from 70.12% to 222.70% and from 59.20% to 194.88%, respectively. At the maximum coverage, the soil bulk density and permeability coefficient decreased significantly and increased. 2) There was no difference in anti-scouribility (AS) of TAL treatment compared with the control, while the rest coverage increased significantly by 2.31-7.57 times, and the GAL treatment AS significantly increased by 0.99-7.12 times as much as the control The greater the effect of the root system to improve soil impact resistance is more significant. 3) The AS of TAL and GAL showed a very significant exponential relationship with bulk density, disintegration rate, water-stable aggregates content and permeability coefficient, respectively, and had extremely significant linear correlation with organic matter content, root biomass and root density. Water-stable aggregates are the key factors that affect soil anti-scourability on the plateau and ditch headland. The results could provide a theoretical basis for the evaluation of ecological functions of the project of returning farmland to forestry and grassland and soil and water erosion control in the study area.