简易土壤养分速测法临洮县教研室康勇农作物生长需要的营养元素氮、磷、钾。在土壤中它们通常以两类化合物的形态存在：一类是可以被作物直接吸收利用的，叫速效养分或有效养分；另一类是不能被作物吸收利用的，叫迟效养分或无效养分。后者可在适宜的水、气、温度和ｐＨ等... Simple Soil Nutrient Quick Measurement Method Linyi County Teaching and Research Section Kang Yong Agricultural Crops Necessary nutrient elements Nitrogen, phosphorus and potassium. In the soil, they usually exist in the form of two types of compounds: one type can be directly absorbed and utilized by crops, called quick-acting nutrients or effective nutrients; the other is not used by crops, called delayed nutrients or no effective nutrients. The latter can be in suitable water, gas, temperature and pH etc...