基于Green-Ampt模型分析坡地种植玉米对降水的促渗作用  

Using the Green-Ampt Model to Analyze Enhanced Infiltration in Slope Corn Field in the Loess Plateau

作　　者：王健[1] 马璠[1,2] 孟秦倩[1] 马玉红 吴发启[1] WANG Jian;MA Fan;MENG Qinqian;MA Yuhong;WU Faqi(Northwest A ＆ F University,Yangling 712100,China;Ningxia Academy of Agriculture and Forestry Sciences,Yinchuan 750000,China;Xi＇an Water and Soil Conservation Station,Xi＇an 710000,China)

机构地区：[1]西北农林科技大学,陕西杨凌712100 [2]宁夏农林科学院,银川750000 [3]西安市水利水土保持工作总站,西安710000

出　　处：《灌溉排水学报》2018年第11期99-105,120,共8页Journal of Irrigation and Drainage

基　　金：国家自然科学基金项目(41771308;41371273)

摘　　要：【目的】探究坡耕地玉米种植对降水入渗的影响,提高对降雨利用率。【方法】以玉米为对象,在3°～15°的坡地径流小区上,人工模拟降雨,测定降雨径流过程,采用水量平衡方法,分析了玉米对降水入渗的影响,利用修正的Green-Ampt模型对入渗过程进行了模拟,利用降雨后期入渗速率确定土壤表征导水率,根据产流时间及降雨强度,确定根系层土壤含水量参数,推求出了水分入渗过程。【结果】在玉米生长过程中,除抽雄后期外,伴随着玉米生长,坡面产流时间延迟,以抽雄期最为显著,平均产流时间由裸地的4.69 min推迟到17.98 min;玉米生长各阶段产流前累积入渗量较裸地明显增大,苗期、拔节期、抽雄期和抽雄后期分别较裸地提高了20.46%、130.91%、272.54%和235.93%;降雨期玉米地累积入渗量高于裸地,苗期、拔节期、抽雄期和抽雄后期分别较裸地增加了2.44%、6.33%、31.01%和24.13%;种植玉米可提高土壤表征导水率,提高土壤入渗能力,土壤含水量参数较裸地有一定提高。【结论】应用Green-Ampt模型的计算值与实测值密切相关,但由于Green-Ampt模型未考虑雨滴对地面打击压实作用,致使计算的土壤入渗能力比实测值偏大。[Objective] Cropping alters soil structure and hence hydrological cycle. This paper aimed to study the influence of corns planted in slope on water infiltration and the water use efficiency. [Method] The experiment was conducted on a slope with slope angle of 3° to 15°; the infiltration of an artificial rainfall was measured. The infiltration process was simulated using the Green-Ampt model, and the steady infiltration rate was determined based on the infiltration rate measured at the late stage of the experiment. We also calculated water deficit parame- ter of the root zone soil and derived soil water infiltration processes based on the surface-runoff time and the pre- cipitation intensity. [Result] The corn field intercepted precipitation and thus delayed the occurrence of surface runoff. The capacity of the interception increased gradually as the corn grew. The efficacy of the tasseling period in reducing surface runoff was most notable, with the average runoff time delayed from 4.69 rain to 17.98 min. The cumulative infiltration before runoff occurred was higher than that on a bare surface, increasing by 20.46%, 130.91%, 272.54%, and 235.93% respectively on the seedling, jointing, tasseling and late tasseling stages. The cu- mulative infiltration in the corn field was also higher than that on a bare surface, increasing by 2.44%, 6.33%, 31.01% and 24.13% respectively on the above four growth stages. Planting corn increased soil hydraulic conduc- tivity, thus improving its infiltration capacity and soil water content, compared to bare soil surface. [Conclusion] The Green-Ampt model is able to simulate water infiltration in the slope planted with corn and the calculated infiltration rate can match with the measured date despite a slight overestimation because the model does not consider the surface compaction induced by raindrops.

关 键 词：降雨入渗 坡耕地 玉米 黄土高原 

分 类 号：TV121[水利工程—水文学及水资源]