Types of Magnesium Fertilizers and Application Methods。
The use of fertilizer is to supplement its nutrition. Then, let’s take a look at the application skills of magnesium fertilizer:
1. The nutritional effect of magnesium
Magnesium is an essential nutrient element for crops, a component of chlorophyll, and can promote photosynthesis; it is an activator of many enzymes, which can promote the synthesis of various substances, such as vitamin A, vitamin C, etc., thereby improving the quality of fruits and vegetables; Promote the absorption of phosphorus and silicon by crops, enhance the nutrient metabolism of phosphorus, and improve the disease resistance of crops.
With the application of nitrogen, phosphorus, potassium and other chemical fertilizers, crop yields continue to increase. Magnesium in the soil is consumed more and less supplemented. The phenomenon of magnesium deficiency in crops has appeared in various places. According to relevant information, currently about 54% of the soil needs to be supplemented with magnesium fertilizer to varying degrees.
2. Types of Magnesium Fertilizer
Magnesium fertilizers can be roughly divided into three categories according to their solubility, namely, water-soluble solid magnesium fertilizers and liquid magnesium fertilizers. The main varieties of water-soluble solid magnesium fertilizers are magnesia, Epsom salt, anhydrous magnesium sulfate, potassium magnesium sulfate, magnesia potassium, among which Epsom salt and magnesia are widely used. Slightly soluble solid magnesium fertilizers mainly include magnesite, periclase, brucite, dolomite, magnesium ammonium phosphate, serpentine, etc. Among them, dolomite is widely used, while magnesite and light burnt magnesia also have application. Liquid magnesium fertilizer is similar to water-soluble magnesium fertilizer in nature. It is a variety used for soilless cultivation and foliar fertilization. It is mainly aqueous solutions of Epsom salt and magnesium nitrate in different concentrations.
3. Application of Magnesium Fertilizer
1. The principle of application:
(1) First used in magnesium-deficient soils. When the effective magnesium content of the soil is 60-120mg/l, it is a magnesium-deficient area; when the effective magnesium content of the soil is less than 60mg/l, it is a severely magnesium-deficient area, and magnesium fertilizer should be applied in time. The effective magnesium content of the soil is closely related to the nature of the soil and the environment in which it is located. It is generally considered that highly leached soils, acidic soils with pH <6.5, low organic matter content, low cation substitution, and soils with poor fertility retention are prone to magnesium deficiency . In addition, due to unreasonable fertilization, long-term excessive application of nitrogen, potassium, and calcium fertilizers will also cause magnesium deficiency due to antagonism between ions. The effective magnesium content of soil in China generally tends to be higher in the north and lower in the south, and all are magnesium-deficient soils south of 32 degrees north latitude.
(2) It is first used for crops that require more magnesium. Crops that require a lot of magnesium, one is cash crops, such as trees, vegetables, cotton, and leaf cash crops such as mulberry, tea, and tobacco. The second is leguminous crops such as soybeans and peanuts.
(3) Select magnesium fertilizer varieties according to soil pH. For neutral and alkaline soils, physiologically acidic magnesium fertilizers, such as magnesium sulfate, should be used; for acidic soils, slow-acting magnesium fertilizers, such as dolomite and magnesium oxide, should be used.
2. Application amount and application method:
(1) Soil application. Magnesium fertilizer can be used for basal fertilizer, top dressing or foliar spraying. To make base fertilizer, it should be mixed with other chemical fertilizers or organic fertilizers before plowing, or mixed with fine soil and then sprayed separately. Topdressing should be applied early, using furrow application or flushing application with water. The appropriate amount of magnesium sulfate per mu is 10-13 kg per mu to the soil, which is 1-1.5 kg per mu of pure magnesium; after a full application, it can be applied in several crops, not every season.
(2) Foliar spraying. Foliar spraying is carried out in the early and middle stages of crop growth. Different crops and different growth periods of the same crop require different spraying concentrations. The total spraying concentration should be controlled with an aqueous solution of magnesium sulfate, which is 0.5%-1.0% for fruit trees, 0.2%-0.5% for vegetables, and field crops such as rice. , Cotton and corn are 0.3%-0.8%, and the amount of magnesium fertilizer sprayed per mu is 50-150 kg.