How long is the shelf life of commonly used chemical fertilizer? Will it fail if it has been kept for a long time? How to store it?

I believe many peasant friends are very concerned about such a question: is there a shelf life for chemical fertilizers? Both agricultural aid shops and farmers will be unable to sell or use up fertilizers after the season has passed, and pile them up for a long time, so the question is, will chemical fertilizers fail if they are stored for a long time? How fast are different fertilizers failing?

Will the chemical fertilizer fail after it has been kept for a long time?

From the analysis of the characteristics of fertilizers, chemical fertilizers can be stored for a long time as long as they are stored properly, the bags are not damaged, not drenched, damp or mixed with alkaline substances, so there is no regulation on the shelf life of chemical fertilizers at present. For example, urea, calcium superphosphate, potassium sulfate and other chemical fertilizers can be stored in cool and dry warehouses for 20 years, except for fertilizer caking, nutrient content and other indicators have not changed.

Some fertilizers will fail after they have been kept for a long time, and some will not fail. It depends on the type of chemical fertilizer. Several main commonly used varieties are introduced as follows:

1. Bicarbonate will not fail but will lose quantity.

In winter, when the temperature is about 0 ℃, the fertilizer effect almost does not change. Farmers can take advantage of the opportunity of seasonal price reduction of ammonium bicarbonate in winter to buy ammonium bicarbonate for spring ploughing.

In summer, when the temperature is more than 30 ℃, ammonium bicarbonate will volatilize a large amount, and the weight of ammonium bicarbonate will be reduced because of ammonia volatilization. Therefore, it is necessary to fasten the mouth of the bag to prevent moisture and reduce the loss.

However, ammonium bicarbonate will not fail for a long time, the fertilizer effect is still very good, according to the dry weight, the fertilizer effect is not reduced. Peasant friends should not regard loss as invalidation.

2. Urea will only lose quantity and will not fail

When dry, it can be kept for a long time. When the temperature reaches 122 ℃, urea decomposes, and the decomposed ammonia and carbon dioxide volatilize at the same time to lose weight. So even if the warehouse is on fire, the properties of the remaining urea remain the same. But urea is afraid of moisture and is easy to lose weight by wet leaching.

3. The fertilizer effect of calcium superphosphate remains unchanged.

In case of rain, the efficiency of fertilizer loss will become worse. For example, the superphosphate produced by phosphate rock powder with high iron and aluminum content should not be stored for more than one year. Because, after about 170 days of storage, the calcium carbonate can be slowly converted into iron phosphate and aluminum phosphate, into insoluble substances, and the fertilizer efficiency becomes worse.

4. Potassium chloride and potassium sulfate are stable.

Potassium chloride and potassium sulfate are very stable compounds, which agglomerate in the presence of water and are applied after crushing, and the fertilizer effect remains unchanged. However, the dosage should be calculated according to the dry weight during application.

5. Diammonium phosphate is afraid of high temperature

Diammonium phosphate in higher temperature, such as the temperature above 30 ℃ will be slowly transformed into monoammonium phosphate, there is a small amount of ammonia volatilization, therefore, the storage of diammonium phosphate should bind the mouth of the fertilizer bag to avoid ammonia volatilization.

6. Ferrous sulfate will deteriorate when it absorbs moisture

Ferrous sulfate is a strong oxidant, which can be easily converted into ferric sulfate if the water is wet, which can not be absorbed by crops. Fertilizer efficiency is poor, easy to fail.

7. Bacteria-containing fertilizer cannot be used when it expires.

There is a time limit for the activity of bacteria in biological fertilizer. The standard of bacterial fertilizer stipulates that the period of validity of the standard bacteria on the package should be two years under normal storage conditions.

Microbial fertilizer can not be used when it expires. Bacterial fertilizer must be kept at low temperature (suitable for 4 ℃-10 ℃), cool, ventilated and away from light, so as to avoid failure.

Some strains need a specific temperature range, such as Trichoderma harzianum needs to be stored in a 2 ℃-8 ℃ incubator, valid for one year, while some Bacillus should be based on the production quality, mainly depends on the level of spore, those with high spore can be preserved for a year and a half or more, and those with bad spoilization are invalid in less than half a year, so vegetable farmers should be careful to choose fertilizer products.

Can not be cheap to choose expired products, such biological bacteria content is very small, no effect, generally more than two years of biological fertilizer should be carefully chosen.

How to store fertilizer scientifically?

In the high temperature and rainy season, chemical fertilizer should be stored in warehouse. The storehouse should not only be ventilated and cooled, but also be rain-proof and moisture-proof. There are two storage methods of fertilizer in the warehouse: bulk storage and bagged storage.

For nitrogen fertilizer varieties with strong hygroscopicity, such as ammonium, whether stored in bulk or in bags, in order to avoid caking, the height of bulk and package piles should be controlled, such as 25-40 kg large bags, with 20 bags as the moderate height.

If you choose a shed for storage, you should choose a place with high terrain, flat ground and no stagnant water, with Reed mats or plastic film underneath. After the fertilizer is stacked neatly, it is covered with plastic film, and at the same time, the roof is set up, covered with cloth and other measures to prevent rain.

"six precautions" should be achieved in the storage of chemical fertilizer:

Anti-volatile ammonia and ammonium bicarbonate are very volatile, so they should be sealed when stored. In addition, nitrogen fertilizer and calcium superphosphate are forbidden to be mixed with alkaline substances such as lime and plant ash to prevent chemical reactions, resulting in volatilization of nitrogen fertilizer and reducing the fertilizer efficiency of phosphate fertilizer.

Second, moisture-proof ammonium, lime nitrogen and calcium superphosphate are easy to agglomerate after moisture absorption, which affects the effect of application. And ammonium bicarbonate moisture absorption, nitrogen volatile, to seal firmly to avoid contact with air. Therefore, these fertilizers should be stored in a dry and cool place.

The third anti-corrosion calcium superphosphate is corrosive and should prevent contact with skin and metal utensils; ammonia is strongly corrosive to copper and iron and should be stored in ceramic, plastic and wooden containers. In addition, chemical fertilizers should not be stacked with seeds, and do not use chemical fertilizers to bag seeds so as not to affect seed germination.

Four anti-high temperature nitrogen fertilizer after the sun, the volatilization loss of nitrogen will be accelerated; ammonium will decompose oxygen at high temperature, which will cause fertilizer failure.

Fireproof ammonium, potassium and other combustion-supporting properties, can not be stored with combustibles such as kerosene, gasoline, straw, sawdust and so on, so as not to cause fire.

Six anti-metal ammonium, potassium and other metal powder mixed with copper, iron and other metal powder, once the friction impact, it will cause an accident. So after these fertilizers are caked and hardened, don't hit them hard with metal, but crush them with heavy ones.