Does fertilizer have a shelf life? Can it still be used after it expires?

Many farmers have surplus chemical fertilizer at home, which will be used next year.

So, do you know how long the shelf life of chemical fertilizer is? Can expired fertilizers continue to be used? Next, Bian Xiao will take you to find out.

Shelf life of chemical fertilizer: According to the characteristics of chemical fertilizer, chemical fertilizer can generally be preserved for a long time as long as it is stored properly and the packaging bag is not damaged, wet, damp or mixed with alkaline substances. Therefore, at present, there is no provision for the shelf life of fertilizers in China.

For example, urea, calcium superphosphate, potassium sulfate and other fertilizers can be stored in a cool and dry warehouse for 20 years, except for fertilizer caking, the nutrient content and other indicators have not changed.

Will some fertilizers fail if they are left for a long time? 1. ammonium bicarbonate: it won't fail, only the quantity will be lost. When the temperature is around 0℃ in winter, the fertilizer efficiency will hardly change. Farmers can take advantage of the seasonal price reduction of ammonium bicarbonate in winter to buy ammonium bicarbonate for spring ploughing.

When the temperature is above 30℃ in summer, ammonium bicarbonate will volatilize in large quantities. Very dry ammonium bicarbonate will get wet due to ammonia volatilization, which will reduce the weight of ammonium bicarbonate.

Therefore, it is necessary to tighten the bag mouth to prevent moisture and reduce losses.

However, ammonium bicarbonate will not fail because of long-term release, and the fertilizer efficiency is still very good. Calculated by dry weight, the fertilizer efficiency will not decrease.

Farmers' friends can't regard losses as failures.

2, urea: will only lose weight, will not fail. When it's dry, it can be kept for a long time.

When the temperature is as high as 122℃, urea decomposes, and the decomposed ammonia and carbon dioxide volatilize at the same time, losing weight.

Therefore, even if there is a fire in the warehouse, the properties of the remaining urea remain unchanged.

However, urea is afraid of moisture, and it is easy to lose weight when it is drenched with water.

3. Calcium superphosphate: The effect of long-term fertilization remains unchanged. If it rains, the loss of fertilizer efficiency will be more serious.

For example, calcium superphosphate produced from phosphate rock powder with high iron and aluminum content should not be stored for one year.

Because, after storage for about 170 days, the calcium carbonate contained in it will be slowly transformed into iron phosphate and aluminum phosphate, which will become insoluble and the fertilizer efficiency will become worse.

4. Potassium chloride and potassium sulfate are very stable compounds. When they agglomerate in water, they are broken and then applied, and the fertilizer effect remains unchanged.

However, the dosage should be calculated on a dry weight basis.

5. Diammonium phosphate will gradually become monoammonium phosphate at higher temperature, for example, a small amount of ammonia will volatilize when the temperature is above 30℃. Therefore, the stored diammonium phosphate should be tied tightly in the fertilizer bag to avoid ammonia volatilization.

6. Ferrous sulfate is a strong oxidant. If it is wet with water, it can be easily converted into ferric sulfate, which can't be absorbed by crops. Poor fertilizer efficiency, easy to fail.

7, microbial fertilizer expired can not be used.

The bacterial fertilizer must be kept in a cool, ventilated and dark place at a low temperature (the appropriate temperature is 4 ~ 10℃) to avoid failure.

Some strains need a specific temperature range, such as Trichoderma harzianum, which needs to be stored in a thermostat at 2-8℃ for one year. However, some bacilli have to be kept for a year and a half or even longer according to the production quality, and the high spore production will fail in less than half a year. Therefore, vegetable farmers should carefully choose bacterial fertilizer products.