交替冻融对坡面产流产沙的影响  

Impacts of freeze-thaw cycles on runoff and sediment yield of slope land

作　　者：魏霞[1,2] 李勋贵[1] Huang Chihua 

机构地区：[1]兰州大学资源环境学院,兰州730000 [2]Agronomy Dep., Purdue Univ., and USDA-ARS National Soil Erosion Research Lab.

出　　处：《农业工程学报》2015年第13期157-163,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(41001154;51109103);中国博士后科学基金项目(20110490862);中央高校基本科研业务费专项资金资助(lzujbky-2014-126;lzujbky-2015-149)

摘　　要：冻融作用使土壤更容易成为侵蚀的物质来源,进而加剧土壤侵蚀程度。为了揭示冻融作用对坡面土壤水蚀的影响,该文通过室内交替冻融循环试验和人工模拟降雨试验,研究了交替冻融作用下坡面的降雨产流产沙特征。试验以未经过任何冻融作用的风干土壤为对照,设计了2种交替冻融循环周期处理(3和6)、2种土壤质量含水率水平(10%和20%)、4种降雨强度(25、50、75、100 mm/h)。结果表明,相对于对照,降雨强度相同时,2种土壤含水率下的交替冻融作用都可以使产流产沙强度增大,且产沙强度的增大幅度大于产流强度。交替冻融循环周期相同时,各降雨强度下的产流产沙强度随含水量的增加而增加。质量含水率相同时,各降雨强度下的产流产沙强度随冻融循环周期的变化相对较为复杂,当质量含水率为10%时,产流产沙强度随冻融循环周期的增加而增大,当质量含水率为20%时,产流产沙强度随冻融循环周期的增加而减小。当质量含水率为10%,交替冻融循环周期为3和6时,增流百分比分别为3.52%、4.71%,增沙百分比分别为6.13%、16.95%。当质量含水率为20%,交替冻融循环次数为3和6时,增流百分比分别为10.24%、5.01%,增沙百分比分别为81.99%、53.07%。相同降雨强度下,土壤质量含水率对产流产沙强度的影响大,交替冻融作用对产流产沙强度的影响小。该研究为冻融侵蚀机理的研究提供参考依据。Although freeze-thaw cycles can alter soil physical properties and microbial activity, their overall impact on soil functioning remains unclear. Soil experiencing freeze-thaw is more vulnerable to become erosion material source of erosion, thereby increasing the severity of a variety of soil erosion. In order to reveal the influence of freeze-thaw effects on soil erosion by water, in this paper we quantitatively tested the hypothesis that soil freeze-thaw processes significantly increase the potential for soil erosion by water during rainfall-runoff events. The freeze-thaw cycles detection system and simulated rainfall equipment were used for the experiment. Control test was designed as an unfrozen soil with air-dried. The experimental design involved four simulated rainfall intensities（25, 50, 75 and 100 mm/h）, two freeze-thaw cycles（FTC=3 and 6） and two kinds of soil moisture mass fraction（10% and 20%） on four 0.5-m-long, 0.2-m-wide, and 0.1-m-deep soil boxes set at 5% slope. Experiments were conducted at the USDA-ARS National Soil Erosion Research Lab. Surface soil（0-10 cm） materials from a Crosby-Miami complex alfisol with 20% clay, 66% silt and 14% sand from the Purdue Animal Science Research and Education Center in West Lafayette, Indiana. The test soil was air-dried, crushed and passed through an 8-mm sieve, and then experienced the designed freeze-thaw pattern. A 100-min continuous rainstorm was applied. The storm consisted of four intensity sequences： 50 mm/h for 60 min, 25 mm/h for 20 min, 75 mm/h for 10 min and 100 mm/h for 10 min. Runoff samples were collected in 1-L HDPE bottles every 5 min during the two lower intensity rains and every 3 min during the two higher intensity rains. Time to fill the runoff bottle was recorded. After each run, the sample bottles were weighed immediately to obtain the runoff rate. Approximately 5 mL of saturated alum solution was added to the sample bottles to flocculate the suspended sediment. After settling overnight, the excess water was poured off t

关 键 词：土壤 侵蚀 产流 冻融 模拟降雨 产沙 

分 类 号：S157[农业科学—土壤学]