EFFECT OF HUMIC ACID ON THE INFILTRATION RESISTANCE OF SOIL WATER

摘要

Humic acid is a kind of macromolecular or-ganic matter which is widely used in various indus-tries. The construction of ecological agriculture, modern agriculture and pollution-free agriculture has been widely applied to humic acid. In order to clarify the effect of humic acid application amount on soil water infiltration, the infiltration experiment was carried out with weathered coal humic acid. Three levels of humic acid application rate and soil initial moisture content were selected in the experi-ment. The soil bulk density was set as 1.35g/cm³，and the blank control group 1 was set. The experi-ment scheme was arranged according to the orthog-onal experiment table L9(3*).The cumulative infil-tration and wetting front migration distance were measured during the experiment, and the influence ofhumic acid on water infiltration was analyzed. The linear regression equations between cumulative in-filtration, wetting front migration distance and test factors were constructed, and the correlation coeffi-cients R were 0.9820 and 0.9668, respectively, indi-cating that the quantitative relationship was feasible. Through the sensitivity analysis of test factors, the results showed that humic acid application amount, soil initial moisture content and cumulative infiltra-tion were significantly negatively correlated, humic acid application amount and migration distance of wetting front were significantly negatively corre-lated, soil initial moisturecontent and migration dis-tance of wetting front were significantly negatively correlated, infiltration time and cumulative infiltra-tion, migration distance of wetting front were sig-nificantly positively correlated. The effect of humic acid on reducing infiltration and preventing infiltra-tion was analyzed. The reducing infiltration rate was 13.14 %,41.71 % and 49.71% respectively,and the preventing infiltration rate was 10.19 %.38.89 %and 40.74 % respectively. The maximum value of re-ducing infiltration and preventing infiltration was nearly half, indicating that humic acid had signifi-cant effect on reducing infiltration and preventingin-filtration of water. In this study, the reference for the comprehensive regulation of water resources in agri-cultural production by studying the permeability re-duction and permeability inhibition of humic acid.