Temporal Change of Topsoil Steady State Infiltration Rate Under Different Land Uses

[Objective] The influence of time variation of topsoil steady state infiltration rate (fc) on water movement and solute transport in the soil profile was studied in order to provide theoretical support for the study of the hydrological cycle model in this region. [Methods] The study was conducted on typical land use types near the Loess Plateau Agricultural Ecological Experimental Station of the Chinese Academy of Sciences. The fc values for a corn field, an apple orchard, and a Robinia pseudoacacia forestland were collected from April to October 2021 using the double ring infiltrometer method. [Results] ① The maximum correlation distance of fc spatial distribution was 7.12 m. ② There was a significant negative correlation between soil bulk density and fc value, while there was no significant correlation between initial soil water content and fc value (p>0.05). ③ From April to May, the fc value for each land use type increased. From June to October, the fc value for each land use type changed differently with time: fc value for the corn field increased first and then decreased, for the apple orchard increased, and for the Robinia pseudoacacia forestland increased first and then stabilized. Variance analysis showed that the fc values for different land uses were significantly affected by time (p