Water-soluble fertilizer, referred to as water-soluble fertilizer, is defined as: dissolved or diluted by water, liquid or solid fertilizer used for irrigation and fertilization, foliar fertilization, soilless cultivation, soaking seeds and dipping roots. As a kind of multi-element fertilizer, water-soluble fertilizer can be quickly dissolved in water and more easily absorbed by crops, and its absorption and utilization rate is relatively high, which can solve the nutritional needs of high-yield crops during the rapid growth period. Especially in the facility agriculture, combined with micro-sprinkler irrigation, drip irrigation, etc., to water with fertilizer, to achieve the integration of water and fertilizer, to save water, fertilizer and labor efficiency. In today's increasingly scarce water resources, the application of water-soluble fertilizer has become one of the measures to increase agricultural efficiency and farmers' income.

 Types and standards of water-soluble fertilizers

Water-soluble fertilizers can be divided into large-element water-soluble fertilizers, trace elements water-soluble fertilizers, humic acid-containing water-soluble fertilizers, amino acid-containing water-soluble fertilizers, etc. China's agricultural industry standards have clear requirements on the quality of related fertilizers.

1. A large number of elements of water soluble fertilizer

A liquid or solid water soluble fertilizer made of trace elements of copper, iron, manganese, zinc, boron, molybdenum or calcium and magnesium is added in accordance with the proportion required for plant growth. The product standard is NY1107-2010, which stipulates that the content of large elements in solid products is ≥ 50%, and the content of trace elements is ≥ 0.2~3.0; the content of large elements in liquid products is ≥ 500g/L, and the content of trace elements is ≥ 2~30g/L.

2. Medium element water soluble fertilizer

A liquid or solid water-soluble fertilizer made of calcium and magnesium in accordance with the proportion required for plant growth, or added with appropriate amounts of copper, iron, manganese, zinc, boron, and molybdenum trace elements. The product standard is NY2266-2012. The technical index of the product is: liquid product Ca≥ 100g/L, or Mg≥ 100g/L, or Ca Mg≥ 100g/L. Solid product Ca ≥ 10.0%, or Mg ≥ 10.0%, or Ca Mg>10.0%. This standard was formally implemented on June 1, 2013.

3. Trace element water soluble fertilizer

Liquid or solid water-soluble fertilizer made of copper, iron, manganese, zinc, boron and molybdenum trace elements in the proportion required for plant growth. The product standard is NY1428-2010. The standard stipulates that the content of trace elements in solid products is ≥ 10%; the content of trace elements in liquid products is ≥ 100g/L.

4. Water-soluble fertilizer containing amino acid

With free amino acids as the main body, according to the proportion required for plant growth, add copper, iron, manganese, zinc, boron, molybdenum trace elements or calcium, magnesium in the amount of elements made of liquid or solid water-soluble fertilizer, the product is divided into trace elements and calcium type two types. The product standard is NY1429-2010. The free amino acid content of trace element type amino acid-containing water-soluble fertilizer is not less than 10% and 100g/L for solid products and liquid products respectively. The total content of at least two trace elements is not less than 2.0 and 20g/L respectively. Calcium-containing amino acid water-soluble fertilizers also have solid products and liquid products, the indicators and trace elements of the same type, only calcium content, solid products and liquid products were not less than 3.0 and 30g/L.

5. Water-soluble fertilizer containing humic acid

Water-soluble fertilizer containing humic acid is a kind of water-soluble fertilizer containing humic acid. Humic acid in the proportion required for plant growth, adding a suitable amount of nitrogen, phosphorus, potassium or copper, iron, manganese, zinc, boron, molybdenum trace elements made of liquid or solid water soluble fertilizer. Humic acid is a kind of animal and plant residues and other organic matter by microbial decomposition transformation and geochemical process and the formation of natural polymer organic matter, mostly from peat, lignite, weathered coal extraction, can stimulate plant growth, improve soil fertility, improve nutrient availability and crop resistance. Product standards for the agricultural industry standard NY1106-2010. The product standard stipulates that the humic acid content of solid products with large elements shall not be less than 3% and the humic acid content of solid products with large elements shall not be less than 20%. The humic acid content of liquid products with large elements shall not be less than 30g/L and the content of large elements shall not be less than 200g/L; The humic acid content of solid products containing humic acid and trace elements shall not be less than 3% and 6% respectively.

6. Other water-soluble fertilizers

Other water-soluble fertilizers with fertilizer efficacy that are not within the scope of the above 5 water-soluble fertilizers and implement corporate standards.

water-soluble fertilizer application method

Water-soluble fertilizers are not only diverse and flexible in application methods, generally in three ways.

1. Drip irrigation, sprinkler irrigation and soilless cultivation

Drip irrigation, sprinkler irrigation and soilless cultivation techniques are often used to save irrigation water and improve labor productivity in areas with extreme water shortages, large-scale farms and the high quality of high value-added cash crops. At the time of irrigation, the fertilizer has been dissolved in the water, watering is also the process of fertilization, that is, the integration of water and fertilizer. At this time, the nutrients needed by plants can be obtained through water-soluble fertilizers, which not only saves water, saves fertilizer, but also improves labor efficiency.

2. Soil irrigation

When the soil is watered or irrigated, it is first mixed in the irrigation water, so that the roots of the plant can be fully exposed to the fertilizer, and the chemical nutrients are transported to the various tissues of the plant through the respiration of the roots.

3. Foliar fertilization

The water-soluble fertilizer is diluted and dissolved in water for foliar spraying, or dissolved in water with non-alkaline pesticides for foliar spraying, and enters the plant through foliar stomata. For some young plants or crops with poor root system, it is the best choice to correct the deficiency, which greatly improves the efficiency of fertilizer absorption and utilization and saves the transportation process of plant nutrients in plants.

Different types of water-soluble fertilizer application methods are different, a large number of trace elements water-soluble fertilizer is mainly used as base fertilizer and top dressing, can also be used for foliar spraying, flushing, soaking, seed dressing and so on. When applying, the water-soluble fertilizer shall be appropriately diluted and mixed with other fertilizers or poured, and special attention shall be paid to the application amount, dilution concentration and application method. Water-soluble fertilizer containing humic acid is mainly used as base fertilizer after mixing fertilizer. 300-400kg of 0.02-0.05 aqueous solution is applied per mu to mix with farmyard manure. 0.01-0.05 aqueous solution is used to pour the vicinity of root system for top dressing, seed soaking and root dipping, for example, rapeseed is soaked with 0.01-0.05 aqueous solution for 5-10 hours. Amino acid water-soluble fertilizer is mainly used as foliar fertilizer in application, and can also be used for seed soaking, seed dressing and root dipping. Soaking seeds is generally soaked in the diluent for 6-8 hours, scooped out to dry and sowed; seed dressing is to evenly spray the diluent on the surface of the seeds and place them for 6 hours before sowing. In actual production, it is necessary to operate strictly according to the requirements of the product manual.