Effect of Land Use on Soil Phosphorus Sorption-Desorption Under Intensive Agricultural Practices in Plastic-Film Greenhouses.

Yang, G.-R., Hao, X., Li, C.L., and Li, Y.-M. (2014). "Effect of Land Use on Soil Phosphorus Sorption-Desorption Under Intensive Agricultural Practices in Plastic-Film Greenhouses.", Pedosphere, 24(3), pp. 367-377. doi : 10.1016/S1002-0160(14)60023-0  Access to full text

Abstract

With rapid urbanization and economic growth, Chinese traditional rice-legume production is increasingly replaced by vegetable and horticultural flower production, which could affect soil properties. This study was conducted near Kunming City, Yunnan Province, Southwest China to investigate how soil phosphorus (P) sorption and desorption processes respond to land use changes and to relate P sorption and desorption parameters to soil properties. Soil samples (0–20, 20–40, 40–60, 60–80 and 80–100 cm) were collected from five sites representing four land use types: rice-legume production in a two-crop, one-year rotation (Rice), vegetable production in open fields (Vegetable), recent (< 3 years) conversion from open fields to plastic-film greenhouse vegetable and flower production at two sites (VFCS1 and VFCS2), and longer-term (> 10 years) plastic-film greenhouse vegetable and flower production (VFCL). The changes in land use affected soil pH, electrical conductivity, available N and P and organic carbon content in topsoil and subsoil. In turn, these changes of soil properties influenced soil P sorption capacity. The P sorption maximum (Smax) was affected by land use types, soil sampling depth and their interactions (P < 0.0001). For surface soil, Smax was in the order of Rice (1 380 mg kg1) > VFCL (1 154 mg kg1) > VFCS2 (897 mg kg1) > VFCS1 (845 mg kg1) > Vegetable (747 mg kg1). The lowest Smaxgenerally occurred at the surface (except for Rice at 80–100 cm) and increased with depth. The amount of P desorbed during the 8 successive extractions was in the range 23%–44% of sorbed P, and was not affected by land use types or sampling depths. The decreases in Smax suggested that soil P sorption capacity decreased when rice-legume production converted to more intensive vegetation and flower production and caution should be exercised when applying P fertilizer to minimize potential leaching and runoff P loss to the environment.

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