How should chemical fertilizers be stored and used in high-temperature weather?

Entering the dog days of summer, it is the season of high temperature and high humidity. Some chemical fertilizers, due to improper storage and improper use, cause farmers to be unwilling to buy them, or fertilization fails to achieve the desired effect. So in the scorching summer, how should fertilizers be preserved and applied to truly bring out their fertilizing power?

1. Storage of chemical fertilizers

Many friends in the agricultural supply business sell fertilizers well, but quite a few have suffered considerable losses due to improper fertilizer preservation. Poorly kept fertilizers tend to cake, causing nutrient loss and thereby affecting product quality.

Hygroscopicity is the root cause of fertilizer caking. After caking, the commercial properties of the fertilizer deteriorate, and farmers are unwilling to buy it. At the same time, fertilizers dissolve easily when exposed to water, causing nutrient loss. Therefore, in the current rainy season, doing a good job of fertilizer preservation, with waterproofing and moisture-proofing, is key.

Generally, there are three ways to store chemical fertilizers: warehouse stacking, shed stacking, and open-air stacking.

In the rainy season, warehouse stacking should be the main method. The warehouse must be both ventilated and cooled, as well as rainproof and moisture-proof. There are two storage methods for fertilizers in the warehouse: bulk stacking and bagged storage.

For nitrogen fertilizer varieties with relatively strong hygroscopicity, such as ammonium nitrate, whether stored in bulk piles or in bags, in order to avoid caking, the storage pressure should be reduced and the height of loose piles and bag piles controlled. For example, for 25-40 kg large bags, 20 bags per pile is a moderate height.

If shed storage is chosen, the stacking site should be selected in a place with higher terrain, level ground, and no water accumulation, with reed mats or plastic film laid underneath. After the fertilizer pile is formed, it should be covered with plastic film on top, while measures such as erecting a shed roof and adding tarpaulins should be taken to prevent rain. Pay special attention: in the rainy season, do not stack chemical fertilizers in the open air.

According to the strength of hygroscopicity, chemical fertilizers can be divided into the following three groups:

(1) Strong hygroscopicity.

Fertilizers with particularly strict storage requirements, such as ammonium nitrate, calcium nitrate, sodium nitrate, ammonium bicarbonate, and some trace element fertilizers. Such fertilizers should avoid bulk storage, and packaging should use double-layer bags, with a plastic bag as the inner lining and a woven bag outside.

(2) Hygroscopic.

Fertilizers with storage requirements, including ammonium chloride, ammonium sulfate, potassium chloride, potassium sulfate, superphosphate, urea, ammonium phosphate, calcium cyanamide, etc.

(3) Low hygroscopicity.

Fertilizers with less strict storage requirements, including phosphate rock powder, bone meal, limestone powder, and gypsum. In principle, any chemical fertilizer should be stored in a dry and cool warehouse.

2. How to apply fertilizer correctly in high-temperature and drought weather?

(1) Apply more phosphate fertilizer. On the one hand, phosphate fertilizer can be used more effectively at higher temperatures, producing good fertilizer effects; on the other hand, phosphate fertilizer can improve the utilization rate of moisture in the soil, playing a mutually promoting role. In addition, sufficient phosphorus can improve the utilization rate of nitrogen, playing the role of using phosphorus to support nitrogen. Reduce the application amount of nitrogen fertilizer, especially ammonium bicarbonate and others that are easily decomposed by heat, because ammonium bicarbonate, which decomposes easily when heated, and high-concentration nitrogen fertilizer easily cause crop seedling burn.

(2) In high-temperature and drought seasons, under strong light, the temperature of bare ground can reach 50°C, evaporation is intense, and the concentration of the surface water solution increases sharply. At this time, if the same amount of fertilizer as in normal weather is applied, crop yield not only cannot be maintained or increased, but is very likely to decrease. For example, when precipitation is moderate, applying 12 kg of pure nitrogen per mu to corn may achieve high yield; if the same amount of fertilizer is still applied during high temperature and drought, it faces the risk of reduced yield.

(3) Applying fertilizer in the morning, although it feels more comfortable for the operators, as the sun rises, the temperature rises sharply, moisture evaporates quickly, the crop absorption time is short, and the fertilizer utilization rate is low; applying fertilizer at noon, due to high temperature, is not conducive to fertilizer absorption or operator activity; applying fertilizer in the evening is both suitable for operator activity and can make up for the shortcoming of short crop absorption time (because nighttime is a process of temperature decrease, surface water evaporation weakens, and moisture retention time is long), making it the best time for fertilization.

3. The essential “six preventions” for fertilizer storage

(1) Prevent volatilization

Everyone knows that ammonia water and ammonium bicarbonate volatilize very easily, so they must be sealed during storage. Also, nitrogen fertilizers and superphosphate are strictly prohibited from being mixed and piled with alkaline substances such as lime and plant ash, to prevent chemical reactions that cause nitrogen fertilizer volatilization and reduce the fertilizer effect of phosphate fertilizer.

(2) Prevent moisture

Ammonium nitrate, calcium cyanamide, and superphosphate easily cake after absorbing moisture, affecting the application effect. Also, after ammonium bicarbonate absorbs moisture, nitrogen volatilizes easily, so it must be sealed firmly to avoid contact with air. Therefore, these fertilizers should be stored in a dry, cool place.

(3) Prevent corrosion

Superphosphate is corrosive and should be prevented from contacting skin and metal tools; ammonia water is strongly corrosive to copper and iron, and should preferably be stored in ceramic, plastic, or wooden containers. In addition, chemical fertilizers cannot be piled together with seeds, and fertilizer bags should not be used to hold seeds, so as to avoid affecting seed germination.

(4) Prevent high temperature

When nitrogen fertilizer is exposed to sunlight, nitrogen volatilization loss accelerates; ammonium nitrate decomposes oxygen at high temperatures, and these will cause fertilizer to become ineffective.

(5) Prevent fire

Ammonium nitrate, potassium nitrate, etc. have combustion-supporting properties, and during storage they must not be piled together with flammable materials such as kerosene, gasoline, straw, and wood shavings, to avoid causing fire.

(6) Prevent explosion

Ammonium nitrate, potassium nitrate, etc. explode easily. If mixed with metal powders such as copper and iron, once rubbed or struck, an explosion accident will occur. Therefore, after these fertilizers cake and harden, do not strike them hard with metal objects; use heavy objects to crush them.