Transport preferences of P forms in wind-blown sediments of two susceptible soils

Abstract

• P forms concentrations of aeolian sediments of different textured soils was assessed. • Mineral and organic P were transported in particulate matter of both soils. • Labile mineral P was transported in saltating sediments of both soils. • Labile P showed a secondary accumulation in particulate matter of the sandy loam soil. • The total P reflected the vertical distribution of the major form, the mineral one. • P forms vertical distribution depended greatly on the bulk soil characteristics. Wind erosion of agricultural soils affects their stock of essential elements for plants, like phosphorus (P). It is known that the composition of the eroded sediments varies with height, according to the size and density of the transported substances. Aim of this study was to analyze the concentration and enrichment ratios of P forms in sediments transported by the wind. A wind-tunnel study was performed on a sandy- and a sandy loam soil in order to measure P forms concentrations in the saltating sediments. P concentrations were also measured in the particulate matter (PM) of each soil, gained with the Easy Dust Generator. In both soils, inorganic- (P i ) and organic P (P o ) were preferentially transported in PM, with enrichment ratios of 1.8 and 5.5, respectively. Nevertheless, a P i /P o of 0.9 indicated that the accumulation of the minor P o in PM was more pronounced than P i . This agrees with P-rich light and easily erodible organic compounds, almost exclusively accumulated in PM, and in relatively heavy and less erodible minerals, like apatites, in lower height sediments. Labile P (P l ) was preferentially transported in saltating sediments of both soils. This was attributed to the selective Bray & Kurtz I’s extraction of the abundant inorganic P forms of these sediments. Total P (P t ) copied the transport trends of P i , the major form. According to the transporting trends, P i and P o would be re-sedimented at longer distances from the source than P l . Outcomes become useful for modeling the influence of wind erosion on P cycling.