有机肥对不同母质菜田土壤磷解吸动力学模拟

通过室内恒温培养试验研究了华南3种典型母质发育的菜田土壤(玄武岩母质发育、花岗岩母质发育、河流冲积物母质发育)在经过两种有机肥(鸡粪堆肥和商品有机肥)预培养30 d和60 d后其土壤有效磷含量及磷解吸动力学过程的影响。结果表明,添加鸡粪堆肥和商品有机肥后,3种母质发育菜田土壤其有效磷含量均显著增加,且添加鸡粪堆肥处理的土壤其有效磷含量的增加量大于添加商品有机肥处理;3种母质发育土壤在添加两种有机肥处理后其磷解吸动力曲线均是先快速解吸然后缓慢达到平衡的过程;磷解吸量不仅与各处理的土壤初始有效磷含量密切有关,而且与土壤成土母质类型、施入有机肥种类相关;3种母质发育的菜田土壤在经过两种有机肥处理后其磷解吸动力曲线用5种动力学方程进行拟合,发现Elovich方程、抛物线方程和幂函数方程能够取得较好的拟合效果。

Simulation of effect of organic manure on phosphorus desorption kinetics in vegetable garden soils different in parent material

Through in-lab thermostat incubation, investigation was done of changes in content of soil available phosphorus and soil phosphorus desorption kinetics, in vegetable garden soils different in parent material (basalt, granite, and river alluvium) in Guangdong Province, 30 d and 60 d after application of organic fertilizers (composted chicken droppings or commodity organic fertilizer). Results show that after the application of composted chicken manure or commodity organic fertilizer, contents of soil available phosphorus in all the three soils increased, with amplitudes showing composted chicken manure was higher in the effect than commodity organic fertilizer. Phosphorus desorption kinetic curves in all the treatments presented a period of rapid desorption followed by a period of slow desorption before reaching equilibrium. Phosphorus desorption in the soil was not only closely related to its initial available phosphorus content, but also to its parent material and the type of the organic fertilizer it received. Five kinetics equations were used to fit the kinetics curves of phosphorus desorption in the three soils different in parent material. The simplified Elovich equation, the Parabolic diffusion low equation and the Power function equation were better in fitting.