Flush Fertilizer Formula and Application Methods Explained in Detail
Flush fertilizer is a method of topdressing; in practice, it means dissolving solid quick-acting chemical fertilizers in water and applying them with water carrying the nutrients. Usually water-soluble fertilizers are used, mainly nitrogen and potassium fertilizers, since both have strong water solubility. By combining fertilizer with water, the soluble nitrogen and potassium nutrients seep into the soil and are then absorbed by crop roots. Let us take a look at flush fertilizer formulas and application methods together below!
Flush Fertilizer Formula Standards
1. The basis of a flush fertilizer formula is a scientific determination of the soil's fertilizer supply capacity, and the basis of that determination is laboratory analysis of the soil and crop trials conducted on that soil. China has many soil types, and soil fertility levels vary greatly. Different soils have different nutrient supply capacities. In actual production, the soil's nutrient supply capacity should be determined according to the soil's properties and soil nutrient content.
2. Different crop species, and even different varieties of the same crop, have different fertilizer requirement patterns. In production, the fertilizer amount and application method should be scientifically determined according to the crop's nutritional characteristics and nutrient requirement patterns.
3. Although each crop has different fertilizer requirement characteristics at different stages and under different environments, the fertilizer ratio needed during the flowering and fruiting stage, which is the key period for flush fertilization, is basically stable. Commonly used flush fertilizers can be classified by category, and several suitable flush fertilizer formulas can be selected. If a fertilizer with reasonable nutrient content, stable quality, and good results is found, it may as well be used continuously. This not only helps to better understand the effects of the flush fertilizer, but also reduces risk.
Classification of Flush Fertilizer Varieties
1. Macro-element types: These include single fertilizers such as nitrogen fertilizer, potassium fertilizer, phosphorus fertilizer, calcium fertilizer, magnesium fertilizer, and sulfur fertilizer, and can also be compound fertilizers, mixed fertilizers, and formula fertilizers, etc., but all must be water-soluble. The usual application rate is from over ten jin to several tens of jin per mu.
2. Macro-element plus micro-element types: These are the above fertilizers with zinc fertilizer, boron fertilizer, iron fertilizer, manganese fertilizer, copper fertilizer, molybdenum fertilizer, chlorine fertilizer, etc. added, and can also be compound fertilizers of several kinds. They must likewise all be water-soluble and must not react with one another or produce precipitates. The application rate is from over ten jin to several tens of jin per mu. This type of flush fertilizer has a better effect than macro-element fertilizers alone; it supplements micro-elements and gives better results in increasing yield and improving quality.
3. Micro-element types: These are flush fertilizers based mainly on zinc fertilizer, boron fertilizer, iron fertilizer, manganese fertilizer, copper fertilizer, molybdenum fertilizer, and chlorine fertilizer, generally mixed and compounded from several kinds, with a certain amount of chelating agent added to increase plant absorption of them and reduce adsorption and fixation by the soil. The usual application rate is from several hundred grams to several kilograms per mu. When applied to plants lacking these elements, this type of fertilizer has a remarkable effect on increasing yield and income by supplementing whichever element is deficient.
4. Amino acid types: Amino acid types use various amino acids as the main raw material, generally amino acids from industrial by-products, or amino acids produced by hydrolysis of hair and waste leather. To improve the effect, various micro-elements are generally added. Because of their relatively strong acidity, they are applied to soils that are not generally too acidic. The application rate is generally from over ten to several tens of jin per mu. The effect is better when applied during the period of maximum plant nutritional efficiency.
5. Humic acid types: Humic acid types are a kind of fertilizer extracted from weathered coal as the main raw material through acidification and alkalization. To enhance efficiency, macro-elements are generally added. Because of their alkalinity, they are applied to slightly acidic soils. The application rate is generally from several jin to several tens of jin per mu. This type of fertilizer has a relatively good effect on improving soil and increasing plant drought resistance.
6. Other types: These include chitin types, seaweed types, other organic matter, industrial fermentation fertilizer types, bacterial fertilizer types, etc. They all have yield-increasing effects and can be used as flush fertilizers. Bacterial fertilizers in particular not only have a very good yield-increasing effect, improve the quality of some crops, and enhance stress resistance, but can also improve the physical and chemical state of greenhouse soil, prevent soil compaction, increase the number and types of beneficial soil microbial communities, and reduce the occurrence of various soil-borne diseases.
Flush Fertilizer Application Methods
1. The large-scale application of flush fertilizer in China is mainly in winter, applied in greenhouses. During this period, due to weak sunlight, low temperature, and low soil temperature, even with external heating sources the needs of normal plant growth still cannot be met. Factors such as low activity of active microbes in the soil and underdeveloped plant root systems all cause poor fertilizer absorption and poor flush fertilizer effects. Therefore, improving plant root vitality and increasing plant root growth are essential measures for flush fertilization.
2. This is mostly because China's agriculture is characterized by a smallholder economy, that is, individual farming, sowing, and fertilizing by each household as a unit. Therefore, soil and fertilizer conditions vary greatly, and it is not easy to uniformly promote the application of a certain fertilizer.
3. Master the nutrient requirement characteristics of various crops. For example, leafy vegetables and gramineous crops need more nitrogen, so we should apply more nitrogen fertilizer as a flush fertilizer; legumes and solanaceous fruits need more phosphorus and potassium, so we should apply more phosphorus and potassium fertilizers as flush fertilizers. Suiting the remedy to the case achieves twice the result with half the effort and improves fertilizer efficiency.
4. Apply scientifically in rotation, with small amounts and multiple applications of flush fertilizer. This is especially true for greenhouse crops. Because they mainly rely on irrigation with water, irrigation is generally frequent, so fertilizer can be applied as a flush fertilizer in small amounts and multiple times. For example, for Chinese chives, it can be applied once after each cutting; for cucumbers, eggplants, peppers, and other solanaceous fruits, it can be applied once after each picking. And at each flush application, rationally combine macro-elements, micro-elements, and plant root growth promoters, etc.
5. Note that several fertilizers cannot be mixed for flush application, otherwise the effect will be reduced or there will be no effect. For example, ammonium bicarbonate cannot be mixed with strongly acidic fertilizers for flush application; amino acid fertilizers cannot be mixed with humic acid fertilizers for flush application; when phosphate fertilizers are mixed with zinc, manganese, iron, copper, and other fertilizers for flush application, a chelating agent must be added, etc.