How to Choose and Use Water-Soluble Fertilizer in Integrated Water and Fertilizer Conservation Technology

Integrated water and fertilizer management is a highly efficient agricultural water conservation technology in which fertilizer is dissolved in water and applied through a piped irrigation system, so that irrigation and fertilization are carried out simultaneously, precisely meeting the crop's water and nutrient needs at the right time and in the right amount, with water and fertilizer managed in sync. Water-soluble fertilizer refers to a multi-element compound fertilizer that can dissolve completely in water. Compared with traditional superphosphate, granulated compound fertilizer and the like, water-soluble fertilizer has clear advantages.

1. Advantages of integrated water and fertilizer technology

(1) Saves water, fertilizer and land

When integrated water and fertilizer technology is applied to winter wheat, brown soil saves 80-100 cubic meters of water per mu, cinnamon soil saves 50-60 cubic meters per mu, with an average saving of more than 70 cubic meters per mu, about 30% water saved, 5-9 kg of chemical fertilizer saved (pure nutrients, the same below), and 10%-25% fertilizer saved;

Summer corn saves 40-60 cubic meters of water per mu, 30%-50% water saved, 8-10 kg of fertilizer saved per mu, and 15%-25% fertilizer saved;

Fruit trees can save 140-180 cubic meters of water, with a water-saving rate of 30%-40%, fertilizer use efficiency increased by more than 10 percentage points, and chemical fertilizer reduced by more than 30 kg per mu.

By adopting micro-sprinkler integrated water and fertilizer management, piped water delivery and sprinkler irrigation are achieved, so ridge furrows and bed ridges are no longer needed, saving about 10% of land compared with traditional irrigation methods and increasing the effective planting area.

(2) Saves labor, time and effort

Visits and surveys of agricultural parks using integrated water and fertilizer management show that with this technology, farmers only need to turn valves on and off to irrigate and fertilize their fields, eliminating heavy, repetitive, primitive field operations such as clearing ridge furrows, scraping bed ridges, scraping border ridges and spreading chemical fertilizer. The operation of integrated water and fertilizer equipment is easy to train and master, and even the elderly and women can do it with ease. For the two crops of wheat and corn, an average of 2 labor-days per mu is saved. Because irrigation efficiency is higher and the amount of irrigation water is reduced, each irrigation cycle can save 3-5 days.

(3) Increases yield, income and efficiency

With micro-sprinkler integrated water and fertilizer technology, winter wheat yields increase by 100 kg per mu, corn by 150 kg per mu, and apple trees by 130 kg per mu, with yield increases of 15%-20%, showing remarkable yield and income gains; compared with traditional irrigation methods, water productivity reaches 2 kg per cubic meter, an increase of 20%-30%, and fertilizer use efficiency rises by more than 15%, achieving highly efficient use of water and fertilizer resources.

2. Water-soluble fertilizer

(1) Characteristics of water-soluble fertilizer

Water-soluble fertilizer is a fast-acting fertilizer that dissolves quickly in water, leaves no residue, and can be absorbed and used directly by the crop's roots and leaves. It can be applied in facility agriculture such as sprinkler and drip irrigation to achieve integrated water and fertilizer management. Its effective absorption rate is more than double that of ordinary chemical fertilizer, and its fertilizer effect is fast, so it can meet the nutrient needs of high-yield crops during rapid growth periods. Used with a sprinkler-drip irrigation system, its water requirement is only 30% that of ordinary chemical fertilizer, and fertilization can be done almost without manual labor, greatly saving costs. Water-soluble fertilizer generally has few impurities and low electrical conductivity, its application concentration is very easy to adjust, and it is safe to use on seedlings.

(2) Water-soluble fertilizer and flush fertilizer

Water-soluble fertilizer and flush fertilizer must not be confused. Flush fertilizer, also called water-flush fertilizer, is a topdressing method in which fertilizer that can dissolve in water is dissolved and applied by flushing as a topdressing. Not all fertilizers can be used as flush fertilizer. Fertilizers suitable for flushing should all have good water solubility, nutrients that are not easily fixed by the soil, easy absorption by plants, a fast fertilizer effect, and no residual toxicity. For example, compound fertilizer, human manure and urine and the like are not flush fertilizers by nature, but when diluted with water into liquid form and applied, they become flush fertilizers.

(3) How to apply water-soluble fertilizer

A. Choose fertilizer according to the irrigation facility

Water-soluble fertilizer has an indicator called “water-insoluble matter content”. Generally, drip irrigation requires a water-insoluble matter content of less than 0.2%, micro-sprinkler irrigation less than 5%, sprinkler irrigation less than 15%, and leaching and pouring applications require even lower. Usually, the lower the water-insoluble matter content, the better the fertilizer effect, and correspondingly the higher the fertilizer price.

B. Avoid direct flushing application

Use the two-stage dilution method. This ensures uniform fertilizer flushing and improves fertilizer use efficiency. Given the crop's characteristic of continuously absorbing nutrients, it reduces leaching losses caused by applying a large amount of fertilizer at one time. Each application of water-soluble fertilizer should preferably be 3-6 kg per mu.

C. Pay attention to details in drip irrigation fertilization

When fertilizing through drip irrigation, first drip clean water, and begin fertilizing once the pipes are full of water. The longer the fertilization time, the better. Immediately after fertilization is finished, drip clean water for 20-30 minutes to flush out all the residual fertilizer solution in the pipes. In principle, the slower and more uniform the fertilization, the better. Especially for elements with poor mobility in the soil (such as phosphorus), extending the fertilization time can effectively improve nutrient use efficiency. When fertilizing through drip irrigation in the dry season, it is recommended to complete fertilization within 2-3 hours.

D. Avoid excessive irrigation

Generally, it is enough to keep the soil layer within 20-40 cm deep moist.

E. About mixing

Use it alone as much as possible, or mix it with non-alkaline pesticides, to avoid metal ions reacting and producing precipitates, which can cause fertilizer burn or pesticide damage to leaves.