Characteristics and Application Methods of Water-Soluble Fertilizers Explained in Detail
The "7 major issues" to watch out for when applying foliar fertilizers: Issue one, the spraying concentration must be appropriate. The spraying concentration of foliar fertilizer directly affects the result; if too high, it easily burns crop leaves; if too low, it not only increases the workload but also fails to achieve the spraying effect, so during spraying it must be based on the crop...
In recent years, various water-soluble fertilizers have successively come onto the market. Many farmers and fertilizer marketers have asked about the characteristics and application methods of water-soluble fertilizers, so an expert was specially invited to answer. For reference.Q: What are water-soluble fertilizers? What types are there? What are the requirements of national or industry standards for product quality?
A: Water-soluble fertilizers refer to liquid or solid fertilizers that can be dissolved or diluted in water and used for fertigation, foliar fertilization, soilless cultivation, seed soaking and root dipping, and other purposes. China is a country short of water resources and emphasizes integrated water and fertilizer management, so developing and rationally applying water-soluble fertilizers is of great significance and has broad development prospects. Product types can be divided into macro-element water-soluble fertilizers, micro-element water-soluble fertilizers, water-soluble fertilizers containing humic acid, water-soluble fertilizers containing amino acids, etc. China's agricultural industry standards have clear requirements for the quality of the related fertilizers.
Macro-element water-soluble fertilizers refer to liquid or solid water-soluble fertilizers with nitrogen, phosphorus and potassium as the main components and with an appropriate amount of micro-elements added. Their product quality must comply with the agricultural industry standard NY1107-2006. This standard stipulates that for solid products, the macro-element content must not be lower than 50%, and the micro-element content must not be lower than 0.5%; for liquid products, the macro-element content must not be lower than 500 grams per liter, and the micro-element content must not be lower than 5 grams per liter.
Micro-element water-soluble fertilizers refer to liquid or solid water-soluble fertilizers made from the micro-elements copper, iron, manganese, zinc, boron and molybdenum in proportions suitable for crop growth. Their product quality must comply with the agricultural industry standard NY1428-2007. This standard stipulates that for solid products, the micro-element content must not be lower than 10%; for liquid products, the micro-element content must not be lower than 100 grams per liter.
Amino acid-containing water-soluble fertilizers are water-soluble fertilizers obtained by mixing and concentrating amino acids with preparations such as calcium and micro-elements, and are mainly used as amino acid foliar fertilizers. The products are divided into two types: micro-element type and calcium element type. The Ministry of Agriculture technical standard NY1429-2007 stipulates that for micro-element type amino acid-containing water-soluble fertilizers, the free amino acid content of solid products and liquid products must not be lower than 10% and 100 grams per liter respectively; the total content of at least two micro-elements must not be lower than 2.0% and 20 grams per liter respectively. Calcium element type amino acid-containing water-soluble fertilizers also have two forms, solid products and liquid products, and all indicators are the same as the micro-element type, except that the calcium element content of solid products and liquid products must not be lower than 3.0% and 30 grams per liter respectively.
Humic acid-containing water-soluble fertilizers are water-soluble fertilizers containing humic acid substances. Humic acid is a type of natural high-molecular organic matter formed from organic matter such as animal and plant residues through microbial decomposition and transformation and geochemical processes. It is mostly extracted from peat, lignite and weathered coal, and can stimulate plant growth, improve soil and increase fertility, improve nutrient availability and crop stress resistance. Product quality must comply with the agricultural industry standard NY1106-2006. Products are divided into Type I and Type II according to humic acid content. The standard stipulates that for macro-element type solid products, the humic acid content of Type I and Type II must not be lower than 3% and 4% respectively, and the macro-element content must not be lower than 35% and 20% respectively; for macro-element type liquid products, the humic acid content (grams per liter) of Type I and Type II must not be lower than 30 and 40 respectively, and the macro-element content (grams per liter) must not be lower than 350 and 200 respectively; for humic acid-containing micro-element type solid products, the humic acid content must not be lower than 3%, and the micro-element content must not be lower than 6%.
Q: How should water-soluble fertilizers be rationally applied? A: Among the above water-soluble fertilizers, macro- and micro-element water-soluble fertilizers, after appropriate dilution, can be mixed with other fertilizers or applied by watering, etc., mainly as base fertilizer and topdressing, and can also be used for foliar spraying, flushing application, seed soaking, seed dressing, etc. Special attention must be paid to the application amount, dilution concentration and application method, so different fertilizers, different application methods, different crops and different growth stages have different requirements. The fertilization amount of macro-element water-soluble fertilizers can be based on soil testing and fertilizer recommendation or the nutrient application amount recommended by experts, then converted into the application amount of water-soluble fertilizer, and it should be stated whether the application amount refers to the stock solution or the diluted solution. Because the utilization rate of water-soluble fertilizers is higher than that of conventional solid chemical fertilizers, the nutrient application amount should be appropriately reduced. Prevent seed burning and seedling burning caused by excessively high fertilizer solution concentration or improper fertilization position. Humic acid-containing water-soluble fertilizers are mainly mixed with fertilizer and used as base fertilizer, applying 300-400 kg of 0.02%-0.05% aqueous solution per mu mixed with farmyard manure, using 0.01%-0.05% aqueous solution to water near the roots as topdressing, seed soaking and root dipping, for example soaking vegetable seeds in 0.01%-0.05% aqueous solution for 5-10 hours, etc.; amino acid fertilizers are mainly used as foliar fertilizers, and can also be used for seed soaking, seed dressing and dipping seedling roots. For seed soaking, generally soak in the diluent for 6-8 hours, remove and dry before sowing; for seed dressing, evenly spray the diluent on the seed surface, leave for 6 hours, then sow. For specific products, strictly follow the requirements of the product instructions.
Q: What are the characteristics of urea ammonium nitrate solution? How should it be rationally applied?
A: At present, urea ammonium nitrate solution on China's fertilizer market is mostly imported, containing 28%-32% nitrogen (N) (by mass), of which ammonium nitrogen and nitrate nitrogen each account for 1/4, and amide nitrogen accounts for 1/2. Because it is completely water-soluble, nitrate nitrogen and ammonium nitrogen are beneficial for seedling development; amide nitrogen takes 4-7 days after application to show effects, so the fertilizer combines quick-acting and slow-acting effects, and the utilization rate is further improved. It is suitable for various crops, especially vegetables. The stock solution can be diluted more than 3 times and mixed with organic fertilizer or soil during land preparation as base fertilizer, diluted more than 4 times and applied with irrigation or as flushing application for topdressing, and diluted more than 50-100 times as foliar fertilizer; the younger the seedling age, the greater the dilution multiple; it can also be used for sprinkler irrigation and drip irrigation. The application amount is generally estimated according to the above method. Note that it should be applied in combination with phosphorus and potassium fertilizers, and do not use flood irrigation or mix it with alkaline fertilizers. For specific application methods, refer to the product instructions.
Agricultural measures are valuable for adapting to local conditions. It is suggested that farmers can first conduct a simple comparative experiment in their own fields for fertilizers they do not understand or have not used, in order to test the effect of the fertilizer and determine the most suitable dosage.