CAJ | 학술논문

坡面流是坡面土壤分离与泥沙输移的驱动力与载体，退耕还林还草工程实施后，可能导致近地表层特征发生改变，集中体现为植被覆盖率提高、植被茎秆及枯枝落叶层出现、生物结皮发育、根系系统的形成，进而引起坡面流水动力学特性的变化。然而，目前对退耕引起土壤近地表层特性变化对坡面流水动力学特性的影响尚不清楚。因此，通过野外放水冲刷实验（坡度12°~14°；单宽流量0.002~0.006 m2/s），系统研究了退耕草地近地表层特征（茎杆-枯枝落叶层、生物结皮、植被根系）对坡面流流速的影响。结果表明：坡耕地撂荒7a后，土壤近地表层特征对坡面流流速影响显著，随着土壤近地表层特性各作用（如根系、生物结皮、植物茎秆及其枯落物）的依次叠加，水流流速依次递减，分别较黄土母质（ T4）减少了12.76%、41.53%和66.78%，且平均流速随枯落物干重、根系重量密度的增大呈幂函数形式下降。研究成果对于理解退耕草地坡面侵蚀动力的变化及其机制，具有重要的意义。
파면류시파면토양분리여니사수이적구동력여재체，퇴경환림환초공정실시후，가능도치근지표층특정발생개변，집중체현위식피복개솔제고、식피경간급고지락협층출현、생물결피발육、근계계통적형성，진이인기파면류수동역학특성적변화。연이，목전대퇴경인기토양근지표층특성변화대파면류수동역학특성적영향상불청초。인차，통과야외방수충쇄실험（파도12°~14°；단관류량0.002~0.006 m2/s），계통연구료퇴경초지근지표층특정（경간-고지락협층、생물결피、식피근계）대파면류류속적영향。결과표명：파경지략황7a후，토양근지표층특정대파면류류속영향현저，수착토양근지표층특성각작용（여근계、생물결피、식물경간급기고락물）적의차첩가，수류류속의차체감，분별교황토모질（ T4）감소료12.76%、41.53%화66.78%，차평균류속수고락물간중、근계중량밀도적증대정멱함수형식하강。연구성과대우리해퇴경초지파면침식동력적변화급기궤제，구유중요적의의。
The implement of the“grain for green project”may cause great changes in near soil surface characteris-tics,which are represented by increasing in vegetation stem and litter cover,developing in biological soil crusts, and forming in plant root system. Overland flow is the driving force for soil detachment and sediment transport and its velocity is probably affected by the changes in near soil surface characteristics greatly. However,the quantitative impacts of the near soil surface characteristics of natural restorated grassland on velocity of overland flow are still unclear. This study was performed to investigate the effects of the near soil surface characteristics( stem-litter,bio-logical soil crust,plant roots)on overland flow velocity in a natural succession grassland under different slope gra-dients(12°~14°)and flow discharges(0. 002 ~0. 006 m2/s). The results indicated that the near soil surface characteristics influenced overland flow velocity significantly. As the near soil surface factors( stem-litter,biologi-cal soil crust,plant roots)overlapped successively,the flow velocity decreased correspondingly. Compared to ve-locity of Loess soil,the mean flow velocity of stem-litter,biological soil curst,and plant roots reduced by 68. 78%, 41. 53%,12. 76%,respectively. The velocity of overland flow decreased as a power function with litter dry weight and root mass density. The results of this study have vital significance to understand the variation and mechanism of erosion dynamics in the natural succession grassland.