Research On The Infiltration Law Of Ridge Tillage Furrow Irrigation Soil Water

Water resources shortage is an eternal theme in our country. Agricultural water-saving is the main way to resolve the contradiction between supply and demand of water resource s. Northeast is a strategic base for our country’s grain security. In the northeast,using ridge tillage,furrow irrigation and moisture of lateral seepage to the ridge furrow irrigation methods.Although it has advantages of convenient, low cost, energy efficiency, less equipment and promotion, etc, there are also problems of large irrigation quota,nonuniformity,severe deep seepage,greater labor intensity,etc.Thus studying soil water infiltration characteristics of ridge tillage and furrow irrigation has an important production and theoretical significance.Based on the ridge tillage and furrow irrigation method in northeast, this test set up three factors including soil bulk density,infiltration water head height,initial soil moisture content for soil water infiltration, each factor had three levels, a total of 27 test samples. This experiment was conducted indoor using soil box simulated test:Soil bulk density clearly influenced soil water infiltration characteristics.Under the test conditions, wetting perimeter length,wetting front vertical infiltration distance,wetting front migration velocity,two adjacent wetting front distance and soil infiltration rate,all showed a decreasing tendency.With the increasing of soil bulk density, and the time was shorter to reach the stable infiltration rate. Soil bulk density had less effect on the wetting front horizontal lateral infiltration distance. At the same horizontal lateral infiltration distance conditions, the increase of soil bulk density could reduce the vertical infiltration distance and the irrigation water requirement.Infiltration water head height significantly influenced soil water infiltration characteristics.Under the test conditions, wetting perimeter length,wetting front horizontal lateral infiltration distance,wetting front vertical infiltration distance,wetting front migration velocity,two adjacent wetting front distance and soil infiltration rate,all showed an increase tendency.With the increase of infiltration water head height, and the time was longer to reach the stable infiltration rate.At the same horizontal lateral infiltration distance conditions, the increase of infiltration water head height could significantly reduce the vertical infiltration distance and the irrigation quota.Initial soil moisture content significantly influenced soil water infiltration characteristics. Under the test conditions, wetting perimeter length,wetting front vertical infiltration distance,wetting front migration velocity,two adjacent wetting front distance and soil infiltrati on rate, all showed an increasing tendency.With the increase of initial soil moisture content, and the time was shorter to reach the stable infiltration rate,initial soil moisture content had less effect on the wetting front horizontal lateral infiltration distance. At the same horizontal lateral infiltration distance conditions, the increase of initial soil moisture content could increase the overall moisture content of wetting body and reduce the infiltration water requirement.Soil bulk density,infiltration water head height,initial soil moisture content clearly influenced irrigation time.Under the test conditions,when the infiltration water head height was 4cm, the initial soil moisture content was 14%,soil bulk density were 1.1g/cm3,1.2g/cm3 and 1.3g/cm3 respectively,the time was respectively 40 min,55min and 85 min that the lateral infiltration distance reached 35 cm,the time was respectively 15 min,20min and 25 min that the water head height reached 12 cm.The increase of soil bulk density led to the increase of infiltration time.When soil bulk density were 1.2g/cm3,the initial soil moisture content was10%, the infiltration water head height were 4cm、8cm and 12 cm respectively, the time was respectively 110 min,65min and 50 min that the lateral infiltration distance reached 35 cm. When the initial soil moisture content was 18%,other conditions remained the same,the time was 50 min,25 min and 15 min respectively that the lateral infiltration distance reached 35 cm.The increase of infiltration water head height led to the reduction of irrigation time. When the soil bulk density were 1.1g/cm3,the infiltration water head height was 8cm, the initial soil moisture content were 10%,14% and 18% respectively,the time was 60 min,25min and 20 min respectively that the lateral infiltration distance reached 35 cm.When soil bulk density was increased to 1.3g/cm3,other conditions remained the same,the time was 85 min,40 min and 30 min respectively that the lateral infiltration distance reached 35 cm.The increase of the initial soil moisture content led to the reduction of irrigation time.Under the test conditions, Infiltration rate of soil and infiltration time had power function, The model imitation had a good result. With Vt=ktn, R2 was up to more than 0.9generally, and the effect was remarkable. There was an obvious positive correlation between the infiltration w ater head height and the initial soil moisture content and the soil infiltration rate.There was an obvious negative correlation between soil bulk density and the soil infiltration rate,but compared to the soil bulk density and the initial soil moisture content, the correlation of the infiltration water head height and the soil infiltration rate was more obvious.