The Study Of Influence Experiment Of Humic Acid On Soil One-dimensional Infiltration And Evaporation

Humic acid is a kind of macromolecule organic matter, it has been applied to agricultural production to improve soil, save water,save fertilizer, increase production and protecte environmental, etc.It has great significance in develping water saving agricultural and water with fertilizer efficient utilization to study humic acid effects on soil water infiltration and evaporation.This article main research conclusions as follows:(1)To study the infiltration characteristics of humic acid solution,used the orthogonal design method, arranged for 16 orthogonal experiment schemes, the humic acid solution one-dimensional vertical water infiltration experiment were carried out. Phillip model was used to fit the relationship of cumulative infiltration of humic acid solution and infiltration time had good correlation.At steady stage ,the infiltration rate and wetting front change rate of humic acid solution were smaller than controlled experimen. Cumulative infiltration and wetting front multiple factors calculation model were established, found that the cornelation was higher. The influence factors on the cumulative infiltration volume and wetting front transport distance from big to small in turn as: Humic acid solution concentration, soil bulk density, soil initial moisture content, and they were negatively correlated.Analyzed the different permeability reducing effect of humic acid solution, loss rate of cumulative infiltration and wetting front were increased with humic acid solution concentration increased. In the infiltration ending, soil moisture content of humic acid solution infiltration scheme were lower than that controlled experiment.(2)Cumulative infiltration and wetting front transport distance of each surface applied humic acid scheme was significantly lower than controlled experiment, and loss rate of them increase with the increased of surface applied humic acid dosage.Infiltration achieved stability about at 120th minutes.Soil initial moisture content had greater effection on cumulative infiltration and wetting front transport distance influence than surface applied humic acid dosage, and they were negatively correlated. The infiltration rate and wetting front change rate were smaller than controlled experiment. After the infiltration ending ,soil moisture content of surface applied humic acid scheme were incrased with surface applied humic acid dosage.(3) In order to study bare soil moisture evaporation characteristics under the condition of the continuous high temperature and the alternation of day and night. Evaporation experiment under the condition of surface applied humic acid in laboratory was carried out, analyized the distribution of soil moisture and the effects of humic acid on the soil moisture evaporation process. To accelerate the evaporation infrared lamp was used as heat source, cumulative evaporation model under continuous illumination and intermittent infrare were established. The cumulative evaporation curve under continuous illumination were smothly increasing,although that of intermittent infrared were fluctuant. Through analyzed the cumulative evaporation loss discoveried that if the initial soil moisture content was same, the cumulative evaporation loss rate increased with surface applied humic acid dosage, increased. If surface applied humic acid dosage was same, the cumulative evaporation loss rate decreased with initial soil moisture content decreased. After the evaporation ending, soil moisture content of surface applied humic acid scheme were higher than that of controlled experiment, and variability of soil moisture vertical distribution, less.