土壤有效水分与化肥相互作用机理及其应用研究——Ⅰ.化肥的盐(度)指数

STUDY ON INTERACTIVE MECHANISM BETWEEN SOIL AVAILABLE WATER AND FERTILIZERS AND ITS APPLICATIONⅠ. The Salt Index of Fertilizers

本文应用电导法测定了12种化肥在纯水和三种土壤真溶液中的盐(度)指数。结果表明:①不同化肥的盐指数差别很大,以硝铵为100时,变化在8(ssp)到118(kc);②以实物计量比养分量更能表达不同化肥的盐指数差异;③不同化肥在纯水和土壤真溶液中的盐指数趋势相似。尿素应以土壤真溶液法测定为准;④电导法与渗透压法测得的盐指数值及其排列顺序相似。化肥盐指数是一个重要参数,对土壤持水量和有效水供应有明显影响,是选择种肥、确定复混肥配方、施肥量和施肥技术等的重要依据。

The present paper expounds the salt index of fertilizers. The salt indexes in pure water and 3 soil true solutions of 12 fertilizers have been determined by electrical conductivity. The results show that:1. The salt indexes of different fertilizers vary from 8 (SSP) to 118(KC) based on salt index 100 of ammonium nitrate (AN).2. When indicting the differences of salt indexes between fertilizers, the actual weight of fertilizers is more suitable than nutrient weight.3. The trends of salt index differences between various fertilizers are similar in pure water or in soil true solutions, while the salt index of urea must be determined by soil true solution.4. The numerical value and their order of salt indexes between different fertilizers determined by eletrical conductivity or osmotic pressure are similar.The salt index of fertilizers, a very important parameter of affecting the soil water retaining capacity and supply of soil available water, can be used effectively to select the fertilizers with seed, work out the formula of compound or mixed fertilizers, determine the fertilization rate and its applying methods and so on.