Effects of soil electric field and mechanical composition on soil phosphorus migration
Soil phosphorus migration with water is one of the important factors in the occurrence of soil erosion and farmland non-point source pollution.In this study,the effects of soil electric field and mechanical composition on phosphorus migrations were investigated.Specifically,soil electric field and mechanical composition were respectively regulated by electrolyte concentrations and types(Na+and K+)as well as the quartz sand particles with a diameter of 2～3 mm.The results indicated that:1)soil phosphorus migration was dominated by particulate phosphorus.For example,in 0.01 mol·L-1 Na+system,the migration quantity of particulate phosphorus was 31 times higher than that of dissolved phosphorus.2)Compared with Na+,K+significantly reduced soil electric field,which in turn reduced soil particulate phosphorus while increased dissolved phosphorus migration.3)Migration quantity of both soil particulate phosphorus and dissolved phosphorus decreased with increasing electrolyte concentration.An increase in the electrolyte concentration decreased the strength and force range of soil electric field,which favored the soil aggregate stability and soil phosphorus retention.4)Addition of quartz sand changed soil mechanical composition,which can significantly change the migrations of soil phosphorus;additionally,the aforementioned change was related to ion type.5)Soil phosphorus migrations were determined by both soil electric field and mechanical composition.This study provides some theoretical reference for the migrations of soil phosphorus and the prevention/control of farmland non-point source pollution.
soil particle interactionsoil electric fieldmechanical compositionphosphorus transport
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