There is a big difference in soil classified fertilization.

? Clay soil

Generally speaking, clay has high content of organic matter, strong fertilizer conservation performance, and it is not easy to lose nutrients, but its permeability is poor, fertilizer effect is released slowly after fertilization, and it is difficult for crops to take root. This kind of soil is often called "growing old seedlings but not young seedlings". This kind of soil is cold, and the decomposition and mineralization of organic matter is slow, so we should apply fully mature farm fertilizer, preferably using hot fertilizers such as horse dung and sheep manure as base fertilizer.

When applying chemical fertilizer, due to the large buffering capacity of the land and strong fertilizer conservation performance, one-time application will not cause burning seedlings or nutrient loss. It is appropriate to apply chemical fertilizer early, "eat more and eat less", and appropriately reduce the number of times. However, nitrogen fertilizer should not be applied too much, so as to avoid excessive fertilizer effect in the later stage, resulting in greedy green and late ripening of crops, resulting in a reduction in yield.

The clay has heavy texture, strong adsorption and fixation ability to nutrients, and the diffusion rate of nutrients in soil solution is slow. Therefore, attention should be paid to the location of the application of chemical fertilizer, such as phosphate fertilizer and potassium fertilizer should be close to the root system as far as possible, and ploughing and loosening the soil in time to enhance soil permeability, pay attention to timely watering, adjust fertilizer with water, and improve fertilizer efficiency.

Sandy soil

The sandy soil has loose texture, more coarse grains, less soil nutrients, and no water conservation and fertilizer conservation. It is advisable to apply more soil miscellaneous fertilizer and organic fertilizer, or to return straw to the field, or to plant green manure in time to improve soil fertility and improve soil structure year by year.

In the application of chemical fertilizer, one can not apply more, more application is easy to lose, should adopt the principle of a small number of times, and should apply less leaching fertilizer, such as ammonium nitrogen, potash fertilizer and so on. It is best to apply chemical fertilizer by concentrated application such as ditch application or hole application. In order to improve sandy soil, the method of mixed soil fertilizer can be used to not only preserve nutrients, but also improve sandy soil. Organic fertilizer should be applied deeply, such as shallow application, it is difficult to decompose or decompose quickly. The sandy soil should use cold fertilizers such as cow manure and pig manure as base fertilizer to make the soil better gradually.

? Loam soil

Loam is a kind of soil with good agronomic characters, and its permeability, water and fertilizer conservation capacity and potential nutrient content are between sandy soil and clay, which is suitable for the growth of all kinds of crops.

In principle, it is necessary to combine long-acting fertilizer with short-acting fertilizer, organic fertilizer with chemical fertilizer, a large number of element fertilizers with medium and trace element fertilizers, and nitrogen, phosphorus and potassium fertilizers.

Paddy field and dry land

Due to the movement of water, the paddy field will take away the nutrients in the solution, making it difficult for the fertilizers to accumulate in the soil, resulting in a lack of nutrients. At the same time, the water in the soil can also dilute the fertilizer applied, so fertilizing even close to the crop root will not harm the crop root system. Do not worry about the accumulation of chloride ions in the soil when applying chlorine-containing fertilizers such as ammonium chloride and potassium chloride in the paddy field. However, due to the existence of water layer in paddy field, it is easy to make the soil anoxic. Under the condition of insufficient supply, some organic and inorganic poisons will be produced. For example, the application of organic fertilizer will accumulate organic acids under the condition of anaerobic decomposition.

Therefore, when selecting organic fertilizers in paddy fields, attention should be paid to the selection of fully mature organic fertilizers, otherwise too many reducing substances will be produced. At the same time, due to the exuberant activity of aerophobic bacteria, it will also increase the consumption of oxygen in water, further aggravate soil hypoxia, and lead to crop root damage. In paddy fields, some organic matter, such as nitrogen, sulfur, iron, manganese and so on, will be in low valence form, that is, nitrogen exists in the form of nitrous acid, iron to ferrous acid, manganese in manganese and sulfur in the form of hydrogen sulfide. Therefore, when applying nitrogen fertilizer in paddy field, it is not suitable to choose fertilizer such as nitrate and potassium sulfate. This is because the former is the most easily dissolved and the fastest moving nutrient in water, in addition to easy leaching, but also easy to form toxic nitrite, and cause denitrification, resulting in nitrogen loss. On the other hand, the application of ammonium fertilizer in paddy field can give full play to its fertilizer effect because it is relatively stable.

In contrast to paddy fields, fertilization in dry land not only does not cause nutrient leaching, but also can gradually accumulate nutrients in the soil, and it is easy to cause excessive salt concentration, so dry land should not be fertilized near the root of the plant.

At the same time, because sulfate reacts with calcium hydroxide and calcium carbonate in soil solution, it can produce insoluble calcium sulfate without increasing soil salt concentration, while chloride ion in potassium chloride can react with calcium sulfate in soil to form water-soluble calcium chloride, which increases the salt concentration of soil solution. Moreover, dry land is not as prone to denitrification as it is in paddy fields. In addition, more crops that like nitrate nitrogen should be planted in dry land. Therefore, it is more suitable to choose nitrate such as ammonium nitrate and compound fertilizer based on ammonium nitrate in dry land.

Saline-alkali soil

Saline-alkali soil is the general name of saline soil and alkaline soil, saline soil mainly refers to the salinized soil with high chloride or sulfate, the soil is alkaline, but the pH value is not necessarily very high; alkaline soil refers to the soil containing carbonate or heavy phosphate, the pH value is alkaline. Saline-alkali soil has low content of organic matter, low soil fertility, poor physical and chemical properties, and many anions and cations harmful to crops, so it is not easy to promote seedlings.

The principle of fertilization in saline-alkali soil is mainly to apply organic fertilizer and high-efficiency compound fertilizer to control the use of low concentration chemical fertilizer. Organic fertilizer contains a lot of organic matter, which can buffer the harmful anions and cations in the soil, which is beneficial to rooting and seedling protection. High-efficiency compound fertilizer has few ineffective components and few residues, but it should not be applied too much each time, so as to avoid aggravating the secondary salinization of the soil. After applying chemical fertilizer, it should be irrigated in time to reduce the concentration of soil solution.