密集型农业下塑料膜温室中不同土地利用方式对土壤磷素吸附-解吸特性的影响

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(VFCS1and 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 kg-1) VFCL(1 154 mg kg-1) VFCS2(897 mg kg-1) VFCS1(845 mg kg-1) Vegetable(747 mg kg-1). The lowest Smax generally 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.

Effect of land use on soil phosphorus sorption-desorption under intensive agricultural practices in plastic-film greenhouses

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 studywas conducted near Kunming City, Yunnan Province, Southwest China to investigate how soil phosphorus (P) sorption and desorption processes respond to land use changesand 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 fivesites representingfour 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. TheP sorption maximum (Smax) was affectedby land use types, soil sampling depth and their interactions ( P < 0.0001). For surface soil, Smax was in the order of Rice (1380 mg kg^-1) > VFCL (1154 mg kg^-1) > VFCS₂ (897 mg kg^-1) > VFCS₁ (845 mg kg^-1) > Vegetable (747 mg kg^-1). The lowest Smaxgenerally occurred at the surface (exceptforRice 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 beexercised when applying P fertilizer to minimize potential leaching and runoff P loss to the environment.