The kinetic characteristics of P adsorption and desorption by organo-mineral colloidal complexes (OMC)were studied using acid, calcareous and neutral purple paddy soils taken from Chongqing and Sichuan, China.The resu...The kinetic characteristics of P adsorption and desorption by organo-mineral colloidal complexes (OMC)were studied using acid, calcareous and neutral purple paddy soils taken from Chongqing and Sichuan, China.The results showed that the P adsorption capacity of the organo-mineral colloidal complexes differed with the soil types, being higher for the acid and calcareous purple soils than for the neutral purple soils. Partial removal of the organic matter increased the adsorption capacity of the colloidal complexes. A very significant positive correlation was found between the amounts of P desorbed from OMC and the P saturation degrees.The P adsorption reaction was quick at the early stage and slowed later. The raise of temperature increased P adsorption capacity and P adsorption rate of the colloidal complexes. The adsorption processes could be described by the Elovich equation.展开更多
High phosphate sorption constitutes a critical impediment to agricultural use of Andosols in the volcanic highlands of Central African Great Lakes region. A laboratory experiment was conducted on soil samples collecte...High phosphate sorption constitutes a critical impediment to agricultural use of Andosols in the volcanic highlands of Central African Great Lakes region. A laboratory experiment was conducted on soil samples collected from an Andosol amended with a factorial combination of lime and P （phosphorus） fertiliser to determine the P sorption characteristics and derive parameter estimates relevant in the prediction and management of P in the Andosols. The potential for sorption of additional P and its binding intensity were evaluated by applying the two-surface Langmuir model to sorption isotherms. The calculated P sorption maxima ranged from 1,667 mg·kg^-1 to 10,000 mg·kg^-1 representing about 95% of the P applied to the soil. The external P requirement ranged from 1,492 mgP·kg^-1 to 2,760 mgP.kgl which is further evidence that the studied Andosols are high P sorbers. There was no significant effect of lime and P rates on P sorption capacity of the Andosols. Exchangeable iron was highly correlated with P sorption maxima b2 （r = 0.98） on the high energy sites, whereas cation exchange capacity was negatively correlated with P sorption maxima bl （r = 0.999） and positively correlated with P binding energy K1 （r = 0.998） on the low energy sites.展开更多
基金the Applied Science Foundation of the Science and Technology Commission of Chongqing,China.
文摘The kinetic characteristics of P adsorption and desorption by organo-mineral colloidal complexes (OMC)were studied using acid, calcareous and neutral purple paddy soils taken from Chongqing and Sichuan, China.The results showed that the P adsorption capacity of the organo-mineral colloidal complexes differed with the soil types, being higher for the acid and calcareous purple soils than for the neutral purple soils. Partial removal of the organic matter increased the adsorption capacity of the colloidal complexes. A very significant positive correlation was found between the amounts of P desorbed from OMC and the P saturation degrees.The P adsorption reaction was quick at the early stage and slowed later. The raise of temperature increased P adsorption capacity and P adsorption rate of the colloidal complexes. The adsorption processes could be described by the Elovich equation.
文摘High phosphate sorption constitutes a critical impediment to agricultural use of Andosols in the volcanic highlands of Central African Great Lakes region. A laboratory experiment was conducted on soil samples collected from an Andosol amended with a factorial combination of lime and P （phosphorus） fertiliser to determine the P sorption characteristics and derive parameter estimates relevant in the prediction and management of P in the Andosols. The potential for sorption of additional P and its binding intensity were evaluated by applying the two-surface Langmuir model to sorption isotherms. The calculated P sorption maxima ranged from 1,667 mg·kg^-1 to 10,000 mg·kg^-1 representing about 95% of the P applied to the soil. The external P requirement ranged from 1,492 mgP·kg^-1 to 2,760 mgP.kgl which is further evidence that the studied Andosols are high P sorbers. There was no significant effect of lime and P rates on P sorption capacity of the Andosols. Exchangeable iron was highly correlated with P sorption maxima b2 （r = 0.98） on the high energy sites, whereas cation exchange capacity was negatively correlated with P sorption maxima bl （r = 0.999） and positively correlated with P binding energy K1 （r = 0.998） on the low energy sites.
