1、为什么要进行测土配方施肥?植物必需的营养元素有16种,其中碳、氢、氧主要来源于空气和水,主要靠土壤供给的可分为三类:第一类是土壤里相对含量较少,农作物吸收利用较多的氮、磷和钾,叫做大量元素;第二类是土壤里含量相对较多,农作物需要确较少,像钙、镁、硫等,叫做中量元素 1, why we need soil testing and fertilizer formula? The plant has 16 kinds of nutrient elements, of which carbon, hydrogen and oxygen are mainly from air and water, mainly by soil supply can be divided into three categories: the first is the soil relative Less content, crop absorption and utilization of more nitrogen, phosphorus and potassium, called a large number of elements; the second is the soil content is relatively large, indeed need fewer crops, such as calcium, magnesium, sulfur, etc., called the amount of elements