FRACTIONS AND ADSORPTION-DESORPTION CHARACTERISTICS OF P IN SOLAR GREENHOUSE VEGETABLE SOILS

This paper deals with the amounts of phosphorus, the fractions of inorganic P and organic P, the percentages of fractions and the properties of phosphate adsorption and desorption in vegetable soils (Fim Orthic Anthrosols) under solar greenhouse conditions. The rusults indicated that the enrichment of phousphorus in the soils was rapid under the level of fertilization in Shenyang of Liaoning. The total P, cowell inorganic P,cowell total P and Olsen P increased by 0.904～1. 824. 5. 050～8. 921, 2. 945～4. 789 and 3. 609～6. 376 times, respectively in the soils continuously cutivated for 3～36 years. Among the inorganic P fraction, Ca-P decreased, but Fe-P and O-P increased. The amount of organic P increased greatly in vegetable soils under greenhouse. The percentage of highly resistant organic P in the organic P increased, whereas the labile organic P declined. The amounts of P adsorbed and desorped in the soils under greenhouse condition increased compared with the uncovered soils.