What Are the Classifications of Compound Fertilizers? A Guide to Choosing the Right One
Compound fertilizer refers to a chemical fertilizer containing two or more nutrient elements. Compound fertilizers have the advantages of high nutrient content, few secondary components and good physical properties. So, what are the classifications of compound fertilizers? How do you choose a compound fertilizer?
I. Classification of compound fertilizers
Because there are many kinds of compound fertilizers, they can be classified in the following ways according to differences in nutrient content.
1. By manufacturing method, they can be divided into two major categories: chemically compounded fertilizers and blended compound fertilizers. Chemically compounded fertilizer refers to fertilizer made by chemical methods that contains 2 or more nutrient elements. Blended compound fertilizer is fertilizer made by mechanically mixing various single-element fertilizers. Chemically compounded fertilizers have stable properties, but the proportions of nutrients such as nitrogen, phosphorus and potassium in them are fixed, making it difficult to adapt to the needs of different soils and various crops. The biggest advantage of blended compound fertilizers is that nitrogen, phosphorus and potassium nutrients can be formulated in various proportions according to the needs of the crop and soil.
2. By the types of nutrients contained, they can be divided into binary compound fertilizers, ternary compound fertilizers and multi-element compound fertilizers. Binary compound fertilizer refers to compound fertilizer containing two of the nutrient elements such as nitrogen, phosphorus and potassium. Ternary compound fertilizer refers to compound fertilizer containing three nutrient elements such as nitrogen, phosphorus and potassium. Multi-element compound fertilizer refers to compound fertilizer that, in addition to the three nutrient elements such as nitrogen, phosphorus and potassium, also has a small amount of trace elements such as boron, manganese, copper and zinc added.
3. By the form in which the nutrient elements exist, they can be divided into potassium sulfate type compound fertilizer, potassium chloride type compound fertilizer, ammonium nitrogen type compound fertilizer, nitrate-ammonium nitrogen type compound fertilizer, etc. In potassium sulfate type compound fertilizer, the potassium nutrient element in the compound fertilizer exists in the form of potassium sulfate, and the packaging must be marked with “sulfur-based” or “potassium sulfate type”. In potassium chloride type compound fertilizer, the potassium nutrient element in the compound fertilizer exists in the form of potassium chloride, and the packaging must be marked with “chlorine-based” or “potassium chloride type”. In ammonium nitrogen type compound fertilizer, the nitrogen nutrient element exists in the form of ammonium chloride, while in nitrate-ammonium nitrogen type compound fertilizer, the nitrogen nutrient element in the compound fertilizer exists in the form of ammonium nitrate.
4. By the length of fertilizer effect, they can be divided into ordinary compound fertilizer, controlled-release fertilizer, slow and controlled-release fertilizer, etc. Controlled-release fertilizer refers to compound fertilizer to which a controlled-release agent is added during processing and production, so that the fertilizer effect is released slowly. Slow and controlled-release fertilizer refers to compound fertilizer to which a slow-release agent and a controlled-release agent are added during processing and production, so that the fertilizer effect can be released slowly according to the needs of the crop.
5. By nutrient content, they can be divided into high-, medium- and low-concentration series compound fertilizers. Generally, the total nutrients of low-concentration compound fertilizer are between 25% and 30%, medium-concentration compound fertilizer between 30% and 40%, and high-concentration compound fertilizer above 40%.
II. Choosing a compound fertilizer
Compound fertilizers have obvious advantages over single-element fertilizers. However, when choosing, care should be taken to select according to the crop type, soil type, application period and the harvested part of the crop. Blindly buying and using compound fertilizer that is not suitable for the local area and the planted crop not only affects crop growth and development and causes waste of individual nutrient elements, but also affects yield. Correctly choosing compound fertilizer in agricultural production is a key link in giving full play to the fertilizer effect and increasing crop yield per unit area.
1. Check the packaging. The outer packaging has three certificate numbers: namely the production license, business license and registration certificate numbers, as well as labeling for the three major nutrient elements nitrogen, phosphorus and potassium, and the manufacturer, address, etc.
2. Check the physical properties of the compound fertilizer. Good-quality compound fertilizer has uniform particle size, does not cake and does not crumble into powder.
When buying, choose a reputable manufacturer; its production equipment and production technology are relatively advanced, and the products produced have uniform particles, balanced nutrients and stable quality. The products are developed by the manufacturer through long-term trials based on soil nutrient conditions and the fertilizer requirements of the crop, with a scientific and reasonable formula, strong targeting, complete nutrients and sufficient content.
3. Choose a suitable compound fertilizer according to the crop or soil environment. For example, for chlorine-sensitive crops such as grapes, potatoes, sugarcane, watermelon, solanaceous crops and tobacco, potassium sulfate type compound fertilizer should be chosen; for wheat, nitrate-ammonium type compound fertilizer can be chosen, because the nitrogen in nitrate-ammonium type compound fertilizer exists in the form of nitrate nitrogen, which wheat can absorb directly, improving nitrogen use efficiency; however, nitrate-ammonium type compound fertilizer cannot be applied to paddy field crops for a long time. When nitrate nitrogen compound fertilizer is used in paddy fields, nitrogen losses are severe due to leaching and denitrification, and long-term application to paddy fields will produce some toxic nitrates and nitrites, which are unfavorable to crop growth.
4. Choose a suitable compound fertilizer according to the crop's fertilizer requirement. For example, grain crops have a relatively high demand for nitrogen but a slightly lower demand for phosphorus and potassium; if phosphorus and potassium are too high, the phosphorus and potassium nutrients will be wasted in vain, and the economic input in fertilizer will instead increase; root and tuber crops have a slightly lower demand for nitrogen but a relatively high demand for potassium; some cash crops have relatively high demands for nitrogen, phosphorus and potassium.