Abstract:

In order to improve the fertilizer retention and reduce the risk of phosphorus leaching of sandy soils that distributes widely in Chongqing City, improved materials confected by biological pretreatment straw, bentonite and PAM were used, the influences on phosphorus adsorption and desorption of the sandy soil result from different materials, dose and ratio were studied. The results showed that: Langmuir equation could reflect the adsorption reaction well. Improved materials could significantly increase the phosphorus adsorption rate of sandy soil, while reduce the desorption rate. The maximum adsorption capacity (Xm) was reduced obviously, while the adsorption constant (K) and maximum buffering capacity of phosphorus (MBC) of the sandy soil was significantly increased. The improvement materials made of rape stalk was better than that of wheat straw. With the increasing amount of application and PAM level, the improvement effect of sandy soil increased gradually. After 90 days in culture, the improvement materials of rape stalk (dose of 10 g/kg, PAM level of 3%) showed the most obvious improvement effect to the sandy soil. This research provided theoretical basis of applying modified straw materials into sandy soil.