A Comprehensive Analysis of Fertilizer Types and Characteristics
Scientific and rational fertilization requires an understanding of the types and characteristics of fertilizers. The fertilizers commonly used in various regions of China today mainly fall into two major categories: organic fertilizers and inorganic fertilizers.
Organic fertilizers mainly include barnyard manure, human excrement and urine, livestock and poultry manure, compost, and green manure. Organic fertilizers contain a variety of nutrient elements and belong to the category of complete fertilizers, but they must undergo decomposition through rotting before they can be absorbed and utilized by the tree body, so they also belong to the category of slow-release fertilizers. Organic fertilizers can increase the organic matter content of the soil, improve the soil's water, fertilizer, air, and heat conditions, and promote the activity of soil microorganisms, thereby playing a role in building up soil fertility, storing water and retaining fertilizer, and continuously supplying nutrients. Organic fertilizers have a slow fertilizer effect and are mostly applied as base fertilizer to increase the reserve and accumulation of nutrients, promote root growth, and enhance the tree body's overwintering resistance. Among them, green manure is an excellent type of organic fertilizer, rich in a variety of nutrient elements. Through planting and applying green manure, the organic matter content in the soil can be increased, the availability of soil nutrients can be improved, the soil structure can be improved, and material cycling can be promoted.
Pictured: walnut
Inorganic fertilizers, also known as chemical fertilizers, can be divided according to the different nutrient elements they contain into nitrogen fertilizers, phosphorus fertilizers, potassium fertilizers, and compound fertilizers. Nitrogen fertilizers mainly include urea, ammonium bicarbonate, ammonium chloride, ammonium sulfate, etc.; phosphorus fertilizers mainly include superphosphate, phosphate rock powder, etc.; potassium fertilizers mainly include potassium sulfate, plant ash, etc.; compound fertilizers mainly include diammonium phosphate, potassium dihydrogen phosphate, nitrogen-phosphorus-potassium compound fertilizer, etc. Chemical fertilizers generally contain relatively single nutrients, but have high nutrient content, strong fertilizer effect, and quick results, and are suitable for application in small amounts multiple times. Chemical fertilizers are prone to leaching, volatilization, or being fixed by the soil after application, and belong to the category of quick-acting fertilizers, and are suitable for application slightly before the period when the tree body needs fertilizer. In production, they are mostly used as top dressing and foliar spray fertilizer, and can also be mixed with organic fertilizers as base fertilizer. For example, before walnut flowering, top dressing with ammonium nitrate, urea, ammonium bicarbonate, etc. can play a role in preserving flowers and fruits, and top dressing with nitrogen and phosphorus fertilizers after flowering can effectively prevent physiological fruit drop. Single-element chemical fertilizers containing only one nutrient element must be applied in combination with other types of chemical fertilizers in order to fully exert their fertilizer effect.