- Sep 22, 2017 -
Fertilizer is one of the material bases of agricultural production, which is to provide a necessary nutrient element for one or more plants, improve soil properties and improve soil fertility level.
Mainly including ammonium phosphate fertilizer, a large number of water-soluble fertilizers, medium element Fertilizer, Bio-fertilizer, organic fertilizer, multi-dimensional field can be enriched and so on.
As early as the Western Zhou Dynasty, the weeds in the field had been known to promote millet growth after decay. The method of planting green manure and the method of crop rotation between leguminous crops and grass crops were described in detail in the Min, and the methods of mixing crop stalks with cow dung and urine by trampling and composting were also mentioned.
In the field of fertilization, the Book of Pan-Sheng has been described in detail, emphasizing the importance of applying the base fertilizer and applying topdressing to the growth of crops. After Tang and Song dynasties, with the popularization of rice in the Yangtze River basin, the fertilization experience accumulated, thus summed up the principle of fertilization, that is, the fertilization should be determined with the change of climate, soil and crop factors.
With the rise and development of modern chemical industry, a variety of chemical fertilizers have come into being. In the middle of 18th century, phosphorus was divided into unit fertilizers (containing only one nutrient element) and compound fertilizers (containing two or more nutrients), such as nitrogen, phosphorus and potash, and the latter was two-element compound fertilizer with N, K and P-K, and nitrogen, phosphorus and potassium ternary compound fertilizer.
Organic fertilizers include nitrogenous fertilizer, synthetic organic nitrogen and so on. People in China used to use livestock and poultry dung, green manure, manure, compost, composting and biogas fertilizer. Organic inorganic, or semi organic fertilizers, are fertilizers made by organic fertilizers and inorganic by mechanical mixing or chemical reactions.
Since a fertilizer often has many properties, in addition to the above classification, there are other common classification methods: ① According to the physical state of fertilizer can be divided into solid and fluid fertilizers. Solid fertilizers are also divided into powdered and granular fertilizers. Fluid fertilizer is a liquid state of fertilizer under normal temperature and pressure. ② according to the chemical properties of fertilizers, can be divided into chemical acid, chemical alkaline and chemical neutral fertilizers. The effect of ③ on soil reaction by the selection of fertilizer by plant can be divided into physiological neutral, physiological alkaline and physiological acidic fertilizer. ④ according to the availability of nutrients to plant, can be divided into quick, late effect and long-term fertilizer.
In order to meet the needs of the development of agricultural modernization, the production of chemical fertilizers, in addition to increasing production, is moving towards high efficiency compounding, combined with fertilization mechanization, transportation fertilizer pipeline, irrigation and fertilizer sprinkler instrumentation direction development. Liquid ammonia, ammonium polyphosphate, potassium polyphosphate and other advantages, such as high nutrient concentration or low accessory components, become the main fertilizer varieties. Many chemical fertilizers also tend to make fluid fertilizers, and in which trace elements of fertilizers and pesticides, become multi-functional compound fertilizer, convenient for pipeline transportation and fertilization irrigation (sprinkler irrigation, drip irrigation) combination, has the advantages of provincial workers, water and provincial fertilizer. With the development of facilities agriculture (such as plastic greenhouses), the demand for carbon dioxide fertilizer by vegetables and fruits will gradually increase. However, the long term application of chemical fertilizers often leads to environmental pollution. In order to maintain the ecological balance of agriculture, it is necessary to promote the use of organic fertilizers and fertilizers in order to avoid the deterioration of soil properties and environmental pollution while satisfying the nutrient needs of crops.
The method of planting green manure and the method of crop rotation between leguminous crops and grass crops were described in detail in the Min, and the methods of mixing crop stalks with cow dung and urine by trampling and composting were also mentioned.