２、同等重要律 对农作物来讲，不论大量元素或微量元素都是同样重要并缺一不可的。缺少某一种微量无素，尽管它的需要量很少，仍会产生缺乏症而导致减产。如玉米缺锌，植株矮小，出现花白苗。棉花缺硼蕾而不花等。 ３、不可替代律 作物需要的各种营养元素，在作物体内都有一定 2, the same important law For crops, regardless of a large number of elements or trace elements are equally important and indispensable. The lack of a trace of trace elements, although its small amount of demand, there will still be a lack of disease led to reduced production. Zinc deficiency, such as corn, plants short, there Hua Bai Miao. Cotton without boron buds and other flowers. 3, Irreplaceable variety of nutrient elements required by law crop, in the body of the crop has a certain