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盆栽试验配台室内分析研究了浙江省四种代表性土壤的磷根摈解吸作用与植物吸收磷之间的关系,结果表明:0.02mol/l KCl溶液或去离子水解吸的磷十分接近于第一个月黑麦吸收的磷;而在0.001 mol/l柠檬酸根溶液中释出的磷相当于头三个月黑麦吸收的磷。在稀电解质溶液或水溶液中释放的磷主要是静电吸附态磷,这部分磷通过扩散作用解吸出。在含竞争性阴离子(柠檬酸根)的溶液中解吸的磷还包括可交换的化学吸附态磷。可见,物理吸附态磷和部分具交换活性的化学吸附磷是土壤中植物速效磷的主要来源。与常规化学提取法(Olsen法和Bray法)比较,本文提出的方法所测得的磷不仅与植物吸收磷相关性较好,而且在数量上比较接近。
Pot experiments were carried out to analyze the relationship between phosphorus desorption and plant uptake of phosphorus in four representative soils in Zhejiang Province. The results showed that the phosphorus desorbed by 0.02 mol / l KCl solution or deionized water was very close to the Phosphorus absorbed by rye for one month, whereas phosphorus released from 0.001 mol / l citrate solution corresponds to phosphorus absorbed by rye in the first three months. Phosphorus released in dilute electrolyte solution or aqueous solution is mainly the electrostatic adsorbed phosphorus, which is desorbed by diffusion. Phosphorous desorbed in a solution containing a competing anion (citrate) also includes exchangeable chemisorptive phosphorus. Visible, physically adsorbed phosphorus and some exchange activity with the chemical adsorption of phosphorus is the main source of plant available phosphorus. Compared with the conventional chemical extraction method (Olsen method and Bray method), the phosphorus measured by the method proposed herein not only has a good correlation with the phosphorus uptake by plants, but also is close in quantity.