Effect of Land Use on Scouring Flow Hydraulics and Transport of Soil Solute in Erosion

Abstract

Water flushing was applied to different land use plots on Loess slopes to examine the effect of land use changes on flow hydraulics and the transport of soil surface solutes in erosion. The runoff and movement of sediment and soil solutes were analyzed in relation to land use and scouring flow. Flow experiments were conducted with five land use treatments: abandoned land (Salsola ruthenica), alfalfa land (Medicago sativa), corn land, scrub land (Caragana intermedia), and bare land. The results show that at the same scouring time, the cumulative sediment yields with different land use types are: bare land > corn land > Caragana intermedia land > abandoned land > alfalfa land. The unit sediment loads are similar to this modulus of the cumulative sediment yields. The pre-experimental water contents of the soil profile exerted a greater effect on the content of soil moisture and its distribution on the slope than that of the antecedent solute contents in the field experiment conditions for different land use types. The land use types also affected the surface transport of soil solute. The bromide concentrations in runoff were in the order of: bare land > corn land > alfalfa land > Caragana intermedia land > abandoned land. The nitrate concentrations in runoff with different land use types had no obvious orderliness. However, the nitrate concentration was lineally related to the bromide concentration, as expressed by CNO� ¼ 3.01CBr� þ 28.35 (R 2 ¼ 0.90). DOI: 10.1061/(ASCE)HE.1943-5584.0000611. © 2013 American Society of Civil Engineers.