Run off-on-out method and models for soil infiltrability on hill-slope under rainfall conditions  

作　　者：LEI Tingwu1,2, LIU Han1, PAN Yinghua3, ZHAO Jun2, ZHAO Shiwei2 & YANG Yonghui2 1. The Key Laboratory of Modern Precision Agriculture System Integration Research, College of Hydraulic and Civil Engineer-ing, China Agricultural University, Beijing 100083, China 2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Yangling 712100, China 3. Geographic and Resources Management College, Yantai Normal University, Yantai 264025, China 

出　　处：《Science China Earth Sciences》2006年第2期193-201,共9页中国科学（地球科学英文版）

摘　　要：The soil infiltrability of hill-slope is important to such studies andpractices as hydrological process, crop water supply, irrigation practices, and soil erosion. A newmethod for measuring soil infiltrability on hill-slope under rainfall condition with run off-on-outwas advanced. Based on water (mass) balance, the mathematic models for soil infiltrability estimatedfrom 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 aslope gradient of about 0° with a runoff/on length (area) ratio of 1 : 1. Case Ⅱ was under arainfall 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. Theexperiments were done with soil moisture of 10%. Required data were collected from laboratoryexperiments. The infiltrability curves were computed from the experimental data. The resultsindicate that the method can well conceptually represent the transient infiltrability process, withcapability to simulate the very high initial soil infiltrability. The rationalities of the methodand the models were validated. The errors of the method for the two cases were 1.82%/1.39% and4.49%/3.529% (Experimental/Model) respectively, as estimated by comparing the rainfall amount withthe infiltrated volume, to demonstrate the accuracy of the method. The transient and steadyinfiltrability measured with double ring was much lower than those with this new method, due towater supply limit and soil aggregates breaking down at initial infiltration stage. The method canovercome the short backs of the traditional sprinkler method and double ring method for soilinfil-traility. It can be used to measure the infiltrability of sloped surface underrainfall-runoff-erosion conditions, in the related studies.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 con-ducted. 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 infil-traility. It can be used to measure the infiltrability of sloped surface under rainfall-runoff-erosion condi-tions, in the related studies.

关 键 词：Infiltrability  runoff-on-out  rainfall  sloped surface  model. 

分 类 号：S157[农业科学—土壤学]