"no matter in the agricultural material shop or in the farmer's household, the fertilizer will be sold out or piled up for a long time because it's past the use season. so the question is, will the fertilizer fail after a long time? how fast do different fertilizers fail? "
will fertilizer fail if it is put on for a long time?
from the analysis of the characteristics of fertilizer, as long as the fertilizer is properly stored, the packaging bag is not damaged, not drenched, not affected by moisture, not mixed with alkaline substances, it can be stored for a long time. therefore, there is no regulation on the shelf life of fertilizer at present.
for example, urea, superphosphate, potassium sulfate and other fertilizers can be stacked in a cool and dry warehouse for 20 years. except for the caking of fertilizer, the nutrient content and other indicators remain unchanged. if the fertilizer is put for a long time, some will fail and others will not. the main varieties are as follows:
1. ammonium bicarbonate will not fail, but will lose quantity
in winter, when the temperature is about 0 ℃, the fertilizer effect hardly changes. farmers can take advantage of the opportunity of seasonal price reduction of ammonium bicarbonate in winter. it is suitable to purchase ammonium bicarbonate for spring ploughing. in summer, when the temperature is over 30 ℃, a large amount of ammonium bicarbonate will volatilize. the very dry ammonium bicarbonate will become moist due to ammonia volatilization, which will reduce the weight of ammonium bicarbonate. therefore, the bag mouth should be tied 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. according to the calculation of dry weight, the fertilizer effect does not decrease. farmers' friends can't regard loss of quantity as failure.
2. urea will only lose quantity and will not fail
when it is dry, it can be kept for a long time. when the temperature is up to 122 ℃, urea decomposes, and the decomposed ammonia and carbon dioxide volatilize at the same time to lose weight. urea is afraid of moisture and is prone to water leaching.
3. superphosphate fertilizer effect unchanged
in case of rain, the loss of fertilizer effect will become worse. for example, 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 storage, the contained calcium carbonate can be slowly converted into iron phosphate, aluminum phosphate, and become insoluble substances, with poor fertilizer efficiency.
4. potassium chloride and potassium sulfate are very stable
potassium chloride and potassium sulphate are very stable compounds. when they are caked in water, they will be used after being broken, and the fertilizer effect will not change. but the dosage should be calculated according to the dry weight.
5. diammonium phosphate is afraid of high temperature
when dap is in high temperature, if the temperature is above 30 ℃, it will slowly change into dap, and a small amount of ammonia will volatilize. therefore, the stored dap should tie the fertilizer bag tightly to avoid ammonia volatilization.
6. ferrous sulfate will deteriorate when absorbing moisture
ferrous sulfate is a strong oxidant. if it is wet in water, it can be easily converted into ferric sulfate, which can not be absorbed by crops. poor fertilizer, easy to lose efficacy.
7. the fertilizer containing bacteria is out of date and cannot be used
there is a time limit for the activity of bacteria in biological fertilizer. according to the standard of bacterial fertilizer, the period of validity of standard bacteria on the packaging bag should be two years under normal storage conditions.
microbial agent (shelf life 18 months), microbial fertilizer can not be used after expiration. the bacterial fertilizer must be kept at low temperature (suitable for 4 ℃ - 10 ℃), cool, ventilated and dark place to avoid failure. some strains need a specific temperature range. for example, trichoderma harzianum needs to be kept in a constant temperature box at 2 ℃ - 8 ℃, with a validity period of one year. however, some bacillus need to be kept for a year and a half or even longer according to the production quality, mainly depending on the level of spore formation. if the spore formation is high, it will fail within half a year. therefore, vegetable farmers should be careful to choose bacterial fertilizer products. it is not allowed to choose expired products at a low price. this kind of biological bacteria has little content and loses efficacy. generally, biological bacteria fertilizer over two years should be carefully selected.
how to store fertilizer scientifically?
fertilizer season is out of date. how to store the remaining fertilizer? farmers' friends must be careful not to let the fertilizer bought with hard money decrease or lose its efficiency due to poor storage. the following four points should be noted:
ammonium bicarbonate is easy to absorb moisture, resulting in the loss of nitrogen volatilization; ammonium nitrate is very hygroscopic, easy to agglomerate and deliquesce; lime nitrogen and superphosphate are easy to agglomerate after absorbing moisture, affecting the application effect. therefore, these fertilizers should be stored in a dry and cool place, especially when ammonium bicarbonate is stored, the packaging should be sealed firmly to avoid contact with the air.
fire protection and sun protection
the loss of nitrogen volatilization will be accelerated after the nitrogen fertilizer is exposed to the sun or high temperature, so the storage of nitrogen fertilizer should avoid the sun and no fireworks.
anti volatilization loss
ammonia water and ammonium bicarbonate are easy to volatilize and lose, so they should be sealed during storage. it is strictly prohibited to mix nitrogen fertilizer and superphosphate with alkaline substances (lime, grass and tree ash, etc.) for stacking, so as to prevent the loss of nitrogen fertilizer volatilization and reduce the fertilizer efficiency of phosphorus fertilizer.
anti corrosion and poison
superphosphate is corrosive to prevent contact with skin and metal utensils; ammonia is highly corrosive to copper and iron, so it should be stored in ceramic, plastic and wooden containers. in addition, the chemical fertilizer cannot be stacked with the seeds, and the seeds shall not be bagged with chemical fertilizer to avoid affecting the germination of the seeds.
scientific and effective storage of chemical fertilizer can not only guarantee the quality of chemical fertilizer, but also reduce the loss caused by improper storage of chemical fertilizer and ensure the interests of farmers.