Do fertilizers have an expiration datea

Do fertilizers have an expiration date?

Whether it is an agricultural material store or a farmer, the fertilizer will not be sold or used up after the use season, and it will be piled up for a long time. Therefore, everyone wants to know, will fertilizers fail if they are stored for a long time?

In fact, according to the characteristics of fertilizers, as long as chemical fertilizers are stored properly, and the packaging bags are not damaged, not exposed to rain, not damp, and not mixed with alkaline substances, they can generally be stored for a long time. Therefore, the country currently has no regulations on the shelf life of fertilizers. For example, chemical fertilizers such as urea, superphosphate and potassium sulfate can be stacked in a cool and dry warehouse for 20 years. Except for the agglomeration of the fertilizer, the nutrient content and other indicators have not changed. Regarding the problem of long-term storage, the following common fertilizers are used as examples to answer your questions:


1. Ammonium bicarbonate will not fail and may reduce weight in summer

In winter, when the temperature is around 0°C, the fertilizer efficiency hardly changes. Farmers and friends can take advantage of the seasonal price reduction of ammonium bicarbonate in winter, and it is appropriate to purchase ammonium bicarbonate for spring ploughing.

In summer, when the temperature is above 30 °C, ammonium bicarbonate will volatilize in large quantities, and the very dry ammonium bicarbonate will become wet due to the volatilization of ammonia, which will reduce the weight of ammonium bicarbonate. Therefore, it is necessary to tie the bag mouth tightly to prevent moisture and reduce losses.

However, ammonium bicarbonate will not fail due to long-term storage, and the fertilizer effect is still very good. Calculated by dry weight, the fertilizer effect does not decrease. Farmer friends can not regard the loss as failure.

2. Urea will not fail, high temperature will reduce weight

When dry, it can be stored for a long time. When the temperature is as high as 122 ℃, urea begins to decompose, and the decomposed ammonia and carbon dioxide volatilize and lose weight at the same time. So even if there is a fire in the warehouse, the properties of the remaining urea remain unchanged. But urea is most afraid of moisture, and it is easy to lose weight by leaching in water.

3. Long-term storage of superphosphate fertilizer will reduce fertilizer efficiency

If it gets wet from the rain, the fertilizer efficiency will be poor. The calcium superphosphate produced by phosphate rock powder with high iron and aluminum content should not be stored for one year. Because the calcium carbonate contained in it can be slowly converted into iron phosphate and aluminum phosphate after being stored for about 170 days, becoming insoluble substances, and the fertilizer efficiency will also decrease.


4. Potassium chloride and potassium sulfate are very stable

Potassium chloride and potassium sulfate are very stable compounds. A small amount of them dissolves in water to cause agglomeration. After they are broken and applied, the fertilizer effect remains unchanged. However, the dosage should be calculated according to the dry weight at the time of application.

5. Diammonium phosphate is afraid of high temperature

When the temperature of diammonium phosphate is higher, such as when the temperature is above 30 ℃, it will slowly transform into monoammonium phosphate, and a small amount of ammonia will volatilize.

6. Ferrous sulfate absorbs moisture and will deteriorate

Ferrous sulfate is a strong oxidant, and it is easily converted into ferric sulfate in case of wet water, which cannot be absorbed by crops. The fertilizer efficiency is poor, and it is most likely to fail.

7. Fertilizer containing bacteria cannot be used after expiration

There is a certain time limit for the activity of bacteria in biological fertilizers. The bacterial fertilizer standard stipulates that the validity period of the standard bacteria species on the packaging bag should be valid for up to two years under normal storage conditions.

The microbial fertilizer has expired and cannot be used. Bacterial fertilizer must be stored in a low temperature (optimum temperature 4℃-10℃), cool, ventilated, dark place to avoid failure. Some strains require a specific temperature range. For example, Trichoderma harzianum needs to be stored in an incubator at 2°C to 8°C, and the validity period is one year, while some Bacillus species need to be produced according to the level of production quality, mainly depending on the level of sporulation, spores, etc. High chemical can be stored for a year and a half or even longer, and bad sporeification will fail in less than half a year. Therefore, vegetable farmers should choose bacterial fertilizer products carefully.

You can't choose expired products for cheap. Such biological bacteria have very little content and lose their efficacy. Generally, biological bacteria fertilizers that are more than two years old should be carefully selected.


Fertilizers do not have a specified shelf life, but they need to be properly stored. The scientific and effective storage of fertilizers not only guarantees the quality of fertilizers, but also reduces the losses of farmers due to improper storage of fertilizers and ensures the interests of farmers.


Post time: Jun-09-2022