Soil Infiltration And Water Salt Distribution Under The Saline Water Supply Conditions

The research of characteristics of soil infiltration and water salt distribution under thesaline water supply conditions of continuous, intermittent and alternate infiltration is animportant guiding role to sustainable use saline water safely and efficiently and it is theprerequisite to achieve agricultural production stability and to ensure stable yields despitedrought or excessive rain. This article based on soil column infiltration test to study thecharacteristics of soil infiltration and water salt distribution under saline water supplyconditions of continuous and intermittent infiltration. Major findings are as follows:1. Experiment under saline water supply conditions of continuous and intermittentinfiltration showed that when mineralization was constant, wetting front distance andcumulative infiltration increased with the increasing infiltration time but the increase ratetended to be reduced. When the period changed in the intermittent infiltration, parameterssuch as wetting front distance and cumulative infiltration showed a certain degree of spurts.The soil moisture content negatively correlated with the soil depth and the rate of changedecreased gradually. Finally the soil moisture content closed to the soil initial moisturecontent in the wetting front place. Electrical conductivity was low in surface soil. Theelectrical conductivity in the middle layer decreased first and then increased. Electricalconductivity presented salt accumulation phenomenon on wetting front places.2. Experiment under saline water supply conditions of continuous and intermittentinfiltration showed that when the net infiltration time constant and the concentration was lessthan3g/l, parameters such as wetting front distance and cumulative infiltration increased withthe increasing concentration. When the concentration was greater than3g/l, characters wereopposite. There was a positive correlation between electrical conductivity and mineralizationin the same depth. The smaller the cycle was and the smaller circulation rate was, the greaterthe wetting front distance and cumulative infiltration were. The smaller the cycle was, the greater the average electrical conductivity and desalination zone depth factor were. Thesmaller the circulation rate was, the greater the average electrical conductivity was, butdesalination zone depth factor was not affected obviously by the circulation rate. Comparedwith continuous infiltration, the intermittent infiltration can increase the capacity ofinfiltration, the rate of salt did not change any more and salt distribution was more uniform.3. Experiment under saline water supply conditions of continuous and intermittentinfiltration showed that wetting front distance, cumulative infiltration and infiltration rate withthe net infiltration time followed the power function equation. There was good linearrelationship between wetting front distance and cumulative infiltration.4. Studies have shown that with the increase of number of alternate, wetting frontdistance and cumulative infiltration has a certain degree of increase in alternation ofcontinuous infiltration.The result of alternation of intermittent infiltration is the opposite. Itdid not essentially change the wetting front distance and cumulative infiltration amount oflinear function relation in alternate irrigation methods. The soil moisture content ratesignificantly reduced with the increase of number of alternate in intermittent infiltration.Electrical conductivity present salt accumulation phenomenon on both ends with saline waterirrigation first. Electrical conductivity presents the overall upward trend with fresh waterirrigation first. The water quality of the last irrigation has a great influence on the surface ofelectrical conductivity.