For the exploration of how the marginal water influenced the subtropical red soil’s water transport parameters

different infiltration experiments were carried out with distilled water (CK)

reclaimed water (RW)

2 times diluted

4 times diluted and 6 times diluted reclaimed water (RW-D2

RW-D4 and RW-D6)

wastewater (WW). The horizontal soil column infiltration absorption method was adopted to measure the transport velocity of wetting front and the water diffusion degree of the red soil and the pressure membrane method was applied to measure the water characteristic curve

in which van Genuchten (VG) model was used to obtain the characteristic parameters

such as residual and saturated values of the soil water content (θr

θs )

α

and n. The results showed that differences existed in the transport velocity of wetting front and the water diffusion degree of the red soil under different water infiltrating condition

the law that the transport velocity of wetting front obeyed could be described as: VCK≈VRW-D2﹥VRW-D6≈VRW-D4﹥VWW﹥VRW

under the same moisture content

conclusion could be made that DRW-D6(θ)﹥DRW-D4(θ)﹥DWW(θ)﹥DRW-D2(θ)﹥DCK(θ)﹥DRW(θ). Different water infiltrating processes had different impacts on the characteristic parameters’ changing rates of the VG model

in which α was the most sensitive while θr was the least sensitive. Therefore marginal water could reduce infiltrating velocity

water-holding capability and drought-resistant ability of the red soil.