What are the disadvantages of chemical fertilizer?

In order to produce more agricultural products, a lot of chemical fertilizers must be put in. At present, fertilizers used in production are mainly divided into two categories, one is organic fertilizer, such as gray manure, manure and green manure, and the other is chemical fertilizer, such as urea, ammonium phosphate and potassium chloride.

The main component of chemical fertilizer is inorganic compound, which is processed and decomposed by chemical fertilizer plant. For example, under the conditions of high temperature, high pressure and catalyst, hydrogen and nitrogen can synthesize ammonia, and then ammonia reacts with carbon dioxide to finally produce urea. For another example, ordinary superphosphate can be made by decomposing phosphate rock powder with sulfuric acid.

Compared with organic fertilizer, chemical fertilizer contains higher fertilizer components. Because of the high content of effective components and small volume, it is convenient for transportation and application, but it is not advisable to use too much at a time, otherwise it will cause the loss of fertilizers and agricultural products. Except for a few varieties, most fertilizers are easily soluble in water, easily absorbed and utilized by plants, and belong to quick-acting fertilizers, but they are easy to deliquesce and agglomerate, resulting in nutrient loss or inconvenient application. At the same time, some chemical fertilizers contain by-products that will adversely affect soil and crops, and some chemical fertilizers, such as ammonium sulfate, will cause soil hardening when used alone during crop growth. In addition, excessive application of chemical fertilizers may also lead to environmental pollution. Therefore, the application of chemical fertilizer should be based on the nature of chemical fertilizer, the demand of crops for nutrients, and the growth conditions of climate, soil and other crops, so that chemical fertilizer can play a greater role in increasing production.