First, according to the nature of fertilizer selection of chemical fertilizer

At present, there are a considerable number of compound fertilizers sold on the market that do not meet the national DB15063-94 standard. National standards stipulate that the compound nutrient (compound fertilizer) is effective nutrient content, the total concentration of high concentrations of NPK is ≥ 40%, the content of low concentration of NPK is ≥ 25%, does not include trace elements and middle elements; water soluble phosphorus content ≥ 40%, the water molecule content is less than 5%; the particle size is 1 to 4.75 mm. Therefore, in addition to looking at trademarks and nutrient content when purchasing compound fertilizers, it is also necessary to pay attention to manufacturers and origins. In addition, there are two kinds of potassium in the compound fertilizer, one is potassium chloride and the other is potassium sulfate. Potassium chloride contains chlorine and should not be applied to bogey crops. Where no “S” symbol is on the compound fertilizer bag, the potash is potassium chloride. Avoid chlorine crops such as grapes, potatoes, tobacco, sugar beet etc. Do not use it. Be sure to use the “S” symbol on the fertilizer bag. Compound fertilizer, compound fertilizer consisting of potassium sulfate.

Second, according to crop species scientific selection of fertilizer

General field crops use N, P and K compound fertilizers; NPK fertilizers should be used in high-yield fields; wheat, rice, millet and other close-cropping crops should be suitable for use with powdered compound fertilizers; sparsely planted crops such as corn should be granular Compound fertilizers; Vegetables, especially fruit and vegetables and root vegetables and fruit trees and other economic crops need more, should use higher potassium, lower nitrogen NPK fertilizer.

Third, according to the soil properties science selection of compound fertilizer

For soils with slightly alkaline, low organic matter content (around 8.0 in soil ph) and lack of available nitrogen and phosphorus, acidic compound fertilizers such as monoammonium phosphate or humic acid NPK fertilizers, nitrogen and phosphorus should generally be used. Compound fertilizer is appropriate. However, alkaline compound fertilizers such as diammonium phosphate should be used for a small amount of red clay or acid brown loam soil.

Fourth, according to the fertilization method scientific selection of compound fertilizer

In order to improve the fertilizer efficiency of compound fertilizers, different formulations should be selected for different application methods. For the application of basal fertilizer, granular compound fertilizer must be used, and the higher the hardness of the particles is, the better the fertilizer efficiency is. The compound fertilizer with compound nitrogen in the compound fertilizer composed of ammonium nitrogen can be used to improve the utilization rate of nitrogen. For top dressing application, powdered compound fertilizer should be used, and it should be noted that the content of water-soluble phosphorus in compound fertilizer should be greater than 40%, and nitrogen is composed of ammonium nitrogen and nitrate nitrogen as the compound fertilizer. should. The general use of humic acid compound fertilizer is better than topdressing.

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