How to use nitrogenous fertilizer
Data ：2017-08-24 03:08View ：
The main role of chlorine in the nutritional balance of crops is to participate in photosynthesis, regulate the osmotic pressure of plant cells, and affect the absorption of nitrogen, phosphorus, potassium, calcium, magnesium, and silicon by crops, enhance crop resistance to diseases and insect pests, and regulate stomatal movement. Chlorine can promote the metabolism of carbohydrates and accelerate the development of crop stem and leaf tissue. Chloride has an inhibitory effect on soil nitrifying bacteria, can delay the conversion of ammonium nitrogen to nitrate nitrogen, and keep a large amount of ammonium ions adsorbed on the soil colloid, so that more ammonium ions can be stored in the soil without loss. Conducive to the preservation of nitrogen.
The conversion of chloride ions in the soil mainly includes: in acid soils, chloride ions combine with hydrogen ions to form hydrochloric acid, which can enhance the acidity of the soil. In neutral and calcareous soils, the residual chloride ions combine with calcium ions to generate more soluble Large calcium chloride. Therefore, long-term application of physiological acid fertilizers such as ammonium chloride and potassium chloride will cause the soil to become acidic and affect the beneficial microbial activities of the soil; on the other hand, the auxiliary components in the fertilizer can combine with the soil calcium to generate chloride calcium. Calcium chloride has high solubility and can be lost with water. Calcium is an indispensable element for the formation of soil structure. Excessive loss of calcium salt will destroy the soil structure and cause compaction.
1 Due to crops containing chlorinated fertilizer
According to the national critical chlorine tolerance test of major crops, comprehensive yield and product quality factors, the degree of chlorine tolerance of crops is divided into three categories: strong chlorine resistant crops, medium chlorine resistant crops and weak chlorine resistant crops.
(1) When the soil oxygen concentration of strong chlorine-tolerant crops reaches 600-800mg/kg, which is equivalent to 1350-1800kg of chlorine per season per hectare, crops that do not affect yield and quality include rice, wheat, corn, sorghum, millet, Kiwi, banana, peach, etc. in cotton, kenaf, radish, tomato, beet, eggplant and fruit trees.
(2) When the chlorine concentration of medium chlorine-tolerant crops is 300-600 mg/kg, which is equivalent to 675-1350 kg of chlorine applied per hectare per season, crops that do not affect yield and quality include flax, soybeans, cauliflower, spinach, broad beans, peas, Strawberry, peanut, apple, hawthorn, sugar cane, etc.
(3) When the chlorine concentration in the soil of weak chlorine-tolerant crops is <300mg/kg, which is equivalent to 675kg of chlorine applied per hectare per season, the crops that do not affect the yield and quality include pepper, Chinese cabbage, potato, lettuce, rape, tobacco, and sweet potato Wait.
The application of chlorinated fertilizers to strong chlorine-tolerant crops does not affect the yield and quality of the crops. According to the quality test results, chlorine has a protein and starch content in the grains of rice, wheat, corn and other crops, a crude protein and fat content in rape and soybean, and a sugar cane. , Sugar content of sugar beet and vitamin C and sugar content in vegetables have no adverse effects. At the same time, the application of chlorinated fertilizers in vegetables can also reduce the nitrate nitrogen content in vegetables.
2 Due to regional application of chlorinated fertilizer
Chlorinated fertilizers should be used mainly in areas with high rainfall or seasons and areas with irrigation conditions. In rainy areas or seasons, after application of chlorinated fertilizers, chloride ions can be lost with water, so the chloride ions brought into the soil with fertilizers will not cause "chlorine damage" due to accumulation. In saline soil, due to the high chloride ion content, less or no chlorinated fertilizer should be used.
3 Containing chlorinated fertilizer should be applied early and deep
Chloride ion can inhibit seed germination, reduce germination rate and emergence rate. Therefore, chlorinated fertilizers should be applied early and deep so that the soil can absorb and chloride ions can be leached, reducing the root damage of crops. The root systems of crops are mostly concentrated in the soil layer of 10-25cm. Therefore, the layer application, strip application and hole application containing chlorinated fertilizer as the base fertilizer should be below 8-12cm.
4 Application of compound fertilizer made of chlorinated fertilizer
Compound fertilizers containing chlorinated fertilizer and urea, ammonium phosphate, heavy calcium or superphosphate, calcium magnesium phosphate fertilizer, potassium sulfate, potassium nitrate and other fertilizers can not only reduce the harm of chloride ions, but also cooperate with nitrogen, phosphorus and potassium Application, can play a complementary effect.
The accumulation of chloride ions is closely related to the annual rainfall, soil texture and planting system. The application of chlorinated fertilizers in arid and less rainy areas, the accumulation of chloride ions in the soil, the residual amount is as high as 30%-80%; in rainy areas in the south, each The amount of chlorine applied per hectare per season is 300-1450kg, and the chloride ion in the soil has not increased significantly in 5 years. According to research, under the condition of 1500mm rainfall, sugar cane, sweet potato and potato, which are considered as "chlorine avoiding crops", have a chlorine application rate of 332-135kg per hectare, which has no adverse effect on yield and quality.