Effect of the number of years of vegetable cultivation on soil phosphorus sorption-desorption characteristics
蔬菜种植年限对土壤磷素吸附解吸特性的影响

An experiment involving 3~5, 15~20 and 25~30 years continuous vegetable cultivation was carried out to determine fixation and release mechanisms of soil phosphorus in cultivated yellow brown soils. Based on the results, phosphorus isothermal adsorption and adsorption-desorption curves are respectively described by Langmuir equation and quadratic equation. With increasing years of cultivation, the maximum phosphorus adsorption (Qm) and maximum buffer capacity (MBC) of surface soil decrease significantly. However, degree of phosphorus saturation (DPS) and phosphorus desorption rate increase. Phosphorus desorption rates in 15~20- and 25~30-year cultivated vegetable soils are significantly higher than that in the 3~5-year cultivated vegetable soils. Correlation analysis for the main factors affecting soil phosphorous adsorption-desorption (e.g., MBC, DPS, etc.) reveals that soil amorphous Fe-Al content significantly affects soil phosphorus adsorption-desorption.