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| Run off-on-out method and models for soil infiltrability on hill-slope under rainfall conditions | |
| 摘 要： | Infiltration is the process of water penetrating into soil, generally referred to as the downward movement of water from the soil surface1,2]. This process is af-fected by water supply and the soil infiltrability, de-termines the amounts of water entering into soil pro-file and the surface runoff. Infiltrability is defined as the infiltration flux of a unit area under atmospheric pressure and sufficient water supply. The actual infil-tration rate and/or the infiltrability is expressed in m/s … |
| 收稿时间： | 8 July 2004 |
| 修稿时间： | 7 August 2005 |
Run off-on-out method and models for soil infiltrability on hill-slope under rainfall conditions |
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| Authors: | LEI Tingwu LIU Han PAN Yinghua ZHAO Jun ZHAO Shiwei YANG Yonghui |
| Institution: | 1. The Key Laboratory of Modern Precision Agriculture System Integration Research, College of Hydraulic and Civil Engineering, China Agricultural University, Beijing 100083, China;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Yangling 712100, China 2. The Key Laboratory of Modern Precision Agriculture System Integration Research, College of Hydraulic and Civil Engineering, China Agricultural University, Beijing 100083, China 3. Geographic and Resources Management College, Yantai Normal University, Yantai 264025, China 4. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Yangling 712100, China |
| Abstract: | The soil infiltrability of hill-slope is important to such studies and practices as hydrological process, crop water supply, irrigation practices, and soil erosion. A new method for measuring soil infiltrability on hill-slope under rainfall condition with run off-on-out was advanced. Based on water (mass) balance, the mathematic models for soil infiltrability estimated from the advances of runoff on soil surface and the water running out of the slope were derived. Experiments of 2 cases were conducted. Case I was done under a rainfall intensity of 20 mm/h, at a slope gradient of about 0° with a runoff/on length (area) ratio of 1: 1. Case II was under a rainfall intensity of 60 mm/h and a slope of 20° with a runoff/on length (area) ratio of 1: 1. Double ring method was also used to measure the infiltrability for comparison purposes. The experiments were done with soil moisture of 10%. Required data were collected from laboratory experiments. The infiltrability curves were computed from the experimental data. The results indicate that the method can well conceptually represent the transient infiltrability process, with capability to simulate the very high initial soil infiltrability. The rationalities of the method and the models were validated. The errors of the method for the two cases were 1.82%/1.39% and 4.49%/3.529% (Experimental/Model) respectively, as estimated by comparing the rainfall amount with the infiltrated volume, to demonstrate the accuracy of the method. The transient and steady infiltrability measured with double ring was much lower than those with this new method, due to water supply limit and soil aggregates breaking down at initial infiltration stage. The method can overcome the short backs of the traditional sprinkler method and double ring method for soil infiltraility. It can be used to measure the infiltrability of sloped surface under rainfall-runoff-erosion conditions, in the related studies. |
| Keywords: | Infiltrability runoff-on-out rainfall sloped surface model |
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