title: A mathematical model for soil solute transfer into surface runoff as influenced by rainfall detachment.
abstract: Nutrients transport is a main source of water pollution. Several models describing transport of soil nutrients such as potassium, phosphate and nitrate in runoff water have been developed. The objectives of this research were to describe the nutrients transport processes by considering the effect of rainfall detachment, and to evaluate the factors that have greatest influence on nutrients transport into runoff. In this study, an existing mass-conservation equation and rainfall detachment process were combined and augmented to predict runoff of nutrients in surface water in a Loess Plateau soil in Northwestern Yangling, China. The mixing depth is a function of time as a result of rainfall impact, not a constant as described in previous models. The new model was tested using two different sub-models of complete-mixing and incomplete-mixing. The complete-mixing model is more popular to use for its simplicity. It captured the runoff trends of those high adsorption nutrients, and of nutrients transport along steep slopes. While the incomplete-mixing model predicted well for the highest observed concentrations of the test nutrients. Parameters inversely estimated by the models were applied to simulate nutrients transport, results suggested that both models can be adopted to describe nutrients transport in runoff under the impact of rainfall.
authors.affiliation: State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China; Department of Environmental Sciences, University of California, Riverside, CA 92521, USA.
authors.forename: Ting
authors.initials: T
authors.lastname: Yang
authors.affiliation: State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, 712100 Yangling, China. Electronic address: wquanjiu@163.com.
authors.forename: Quanjiu
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Environmental Sciences, University of California, Riverside, CA 92521, USA.
authors.forename: Laosheng
authors.initials: L
authors.lastname: Wu
authors.affiliation: State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
authors.forename: Guangxu
authors.initials: G
authors.lastname: Zhao
authors.affiliation: State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
authors.forename: Pengyu
authors.initials: P
authors.lastname: Zhang
keywords: Detachment; Mixing depth; Model; Nutrients transport; Rainfall