In order to investigate the influence of infiltration water quality on soil hydraulic characteristics

two types of water (distilled and tap water) were selected to carry out in four pressure heads (0

-3

-6

-9 cm) on yellow loam and red loam by using a disc infiltrometer. The results showed that infiltration rate

hydraulic conductivity and sorptivety increased with the increase of the water electrical conductivity

and the soil sorptivety in red loam differed significantly under different conductivity of water (P<0.05). Under the low head pressure

the soil hydraulic conductivity was significantly different between two types of water (P<0.05). By contract

the difference of soil hydraulic conductivity between two types of water was not significant under high head pressure. The influence of water quality on (fine pore) soil hydraulic conductivity was mainly under the low pressure head. The contribution of macropores and medium porosity in the yellow and red loam soils to water flow increased with the increase of the conductivity of water. However

the contribution of the small pores to the flow decreased with the increase of the conductivity of water. Different types of water had significant influence on the contribution rate of different grades of porosity to water flow in red loam (P <0.05). Study of the influence of water quality on soil hydraulic characteristics was beneficial for discussing the influence of water quality on the experimental results

correctly understanding the soil hydrological processes

developing and utilizing low quality water resources

and improving irrigation quality and irrigation efficiency.