Laboratory investigation of phosphorus loss with snowmelt and rainfall runoff from a Steppe wetland catchment

Phosphorus (P) losses from terrestrial soils contribute to eutrophication of surface waters. As priority non-point source pollution ways, rainfall runoff (RS₁) and snowmelt runoff (RS₂) are the main carrier of P loss from terrestrial ecosystem. The aim of this study was to investigate the similarities and differences between P loss with RS₁ and RS₂ of the same soil type. Six types of soil were used in this experiment. Results have shown that 1), Different types of soil have different P loss with RS₁ and RS₂ under different slope, and the changes ranged from 0.003 to 0.370 mg L^-1. 2), The effects of soil type, slope and runoff type on P loss with surface runoff was not independent, both individual effects of all factors and their interaction with the other two factors effected the P loss with runoff. 3), In our experiment, some soils showed no significant difference between P content in RS₁ and RS₂. In some soils, P loss with RS₁ was higher than that with RS₂ while the opposite conclusion was showed in Bog soil (BS) which with higher soil water content. 4), The P loss with RS₁ and RS₂ of different soils were both mainly affected by soil water content (SW), Olsen-P content (OP) and soil organic matter content (OM). These results can help us understand the P loss with different patterns of surface runoff better and are expected to provide pertinent opinions on the analysis of P loss with runoff and its influencing factors of grassland soils.