Four factors should be considered in the selection of compound fertilizer

Compound fertilizer has many advantages, such as many kinds of nutrients, which can supply a variety of nutrients needed by crops at the same time, giving full play to the role of mutual promotion among nutrient elements, high effective nutrients and obvious economic benefits, in high concentration compound fertilizer, the content of effective components accounts for at least 30%, most of which are more than 40%, and some are as high as 60%. At present, the effective nutrients of unit chemical fertilizers produced in China account for about 20%, and their weight and volume are more than twice that of high-concentration compound fertilizers with the same nutrient concentration. The use of compound fertilizers can save the costs of fertilizer packaging, transportation, distribution and application, and reduce production costs; compound fertilizer has little side effects, little adverse effect on soil, small hygroscopicity, not easy to caking, convenient storage and use, so it is very popular.

? How to choose to use compound fertilizer reasonably?

1. Consider the soil quality

For soils with slightly alkaline, low content of organic matter and lack of available nitrogen and phosphorus, acid nitrogen and phosphorus compound fertilizer, such as monoammonium phosphate or humic acid nitrogen, phosphorus and potassium compound fertilizer, nitrogen and phosphorus compound fertilizer should be selected.

But for a few red clay or acid brown loam, chemical alkaline compound fertilizer, such as diammonium phosphate, should be selected.

2. Consider crop varieties

In general, nitrogen and phosphorus compound fertilizer should be selected for field crops, nitrogen, phosphorus and potassium ternary compound fertilizer for wheat or high yield fields, powdered compound fertilizer for closely planted crops such as wheat, rice and millet, granular compound fertilizer for sparse planting crops such as corn, phosphorus and potassium compound fertilizer for legume crops, and ternary compound fertilizer suitable for local soil and crops for some cash crops. Compound fertilizer with high potassium content should be selected for rhizome crops (lotus root, Polygonatum odoratum), corn, late rice and so on.

Relatively speaking, early rice, peanut, sesame, rape, pepper and other crops should choose compound fertilizer with high phosphorus content, leaf vegetables should choose compound fertilizer with high nitrogen content, and chlorine-free or low chlorine content compound fertilizer should be selected for chlorine-free crops such as watermelon, strawberry, citrus, flue-cured tobacco, tea and grapes.

3. Mixed with simple fertilizer

The nutrients of compound fertilizer are fixed, and in order to give better play to its role in increasing production, we should also cooperate with the application of elemental fertilizer to regulate the needs of crops for different nutrients in different growth stages. For example, crops such as rice, corn and wheat need more nitrogen during the growing period. if diammonium phosphate with less nitrogen and more phosphorus is selected, the amount of phosphorus should be calculated first, and the insufficient nitrogen should be supplemented by simple nitrogen fertilizer. If you first calculate the amount of nitrogen to meet the crop nitrogen, then there will be too much phosphorus, resulting in a waste of fertilizer.

4. Consider the application method.

For example, as a base fertilizer, granular compound fertilizer must be selected, and the higher the hardness of the particles, the better, so as to prolong the fertilizer effect; for compound fertilizers containing ammonium nitrogen, it is easy to be absorbed by the soil and not easy to be leached, so it is suitable for all kinds of soil and crops, but it is best to carry out deep application to improve the utilization rate; for nitrate compound fertilizer, it is not suitable to be applied to paddy fields, but to dryland crops because it is not absorbed by the soil and is easily leached with water.

Nitrogen and phosphorus compound fertilizers with more phosphorus and less nitrogen can be deeply applied as base fertilizer and nitrogen fertilizer can be used as topdressing to supplement nitrogen deficiency. Compound fertilizers with higher prices, such as potassium dihydrogen phosphate, are generally not used as base fertilizer, but are best used as seed soaking or extra-root topdressing. When choosing nitrogen, phosphorus and potassium ternary compound fertilizer as seed fertilizer, it is necessary to consider that the content of nitrogen is not too high, otherwise it is easy to burn seeds and seedlings. (Liu Qixun)