土壤磷素解吸模型及其特征值的作物效应

土壤有效磷数量和强度及其缓冲系数是评价土壤磷素供应能力的重要指标。通过解吸实验、盆栽和田间试验研究土壤磷解吸特性及其与供试蔬菜的效应。38个磷素解吸实验表明,土壤镉解吸模型的修正式能很好地模拟土壤磷素解吸动态特征,有32个回归模型达到显著水平。土壤磷解吸模型可同时求得表征土壤磷有效性的磷可解吸数量Q和土壤溶液初始磷浓度Cli及其缓冲系数b。盆栽试验表明,土壤磷解吸特征值Q和Cli与空心菜(Iponoea aqatica)和菜心(Brassica parachinensis)吸P量有显著水平的抛物线型关系,且与土壤类型无关。田间试验表明,Q值与供试蔬菜鲜重产量亦有显著水平的抛物线型关系,可求得试验条件下空心菜和莴苣(Lactuca sativa)磷肥施用的Q值临界指标分别为11mg/kg和13mg/kg。解吸模型研究为评价土壤磷素有效性提供了一种新方法。

Phosphorus desorption model of soil and crop effect of its eigenvalue

The quantity of soil available phosphorus and intensity and its buffer coefficient are the important indexes to evaluate supply capacity of soil phosphorus. Lab experiment, pot experiment and field experiment were conducted to study desorption characteristics of soil P and effect of soil P on vegetables. 38 experiments of P desorption showed that modification formula of Cd desorption model in soil simulated well dynamical characteristics of soil P desorption. There were 32 regression models reached significant level. It were gained on base of desorption model that desorptable nutrient quantity (Q) which is biological available P in soil and original P content of soil solution (Cli) and buffer coefficient (b). The results of pot experiment showed that it existed statistic significant level of parabola model relation between Q or Cli and P uptake quantity by the vegetable for water convolvulus (Iponoea aqatica), flowering Chinese cabbage(Brassica parachinensis), which had nothing with soil types. The results of field trial showed that it also existed statistic significant level of parabola model relation between Q and the output of fresh vegetable, which gained critical index of Q of P application to water convolvulus and lettuce(Lactuca sativa)that were 11 mg/kg and 13 mg/kg respectively. The studies on desorption model afforded a new method to estimate biological validity of soil P.