Storage of Fertilizer: Good Practices

High quality fertilizers allow precise and regular spreading, the pillar of efficient fertilization to reach yield and quality objectives. Beyond the chemical composition of fertilizers, it is essential that they have impeccable and stable physical qualities. In order to store fertilizers in the best possible way so as not to alter their effectiveness or stability, Yara provides you with some advice on how to store and handle fertilizer properly.

Heat and humidity

Humidity is the main enemy of fertilizer. It causes a physical degradation of the granules, which usually results in a caking phenomenon. Packaging in big bags reduces this risk. The storage on pallets allows to isolate the big-bags from the soil humidity. The integrity of the big-bags isolates the fertilizer from contact with humidity.

Heat is also a source of fertilizer deterioration. The sun’s rays on the big-bags or simply the heat accumulated in a non-ventilated building are enough to make the fertilizer rise in temperature. At 32°C the fertilizer expands; a drop in temperature (at night, for example) returns the ammonium nitrate to its original form. But several repetitions of such a heating-cooling cycle deteriorate the fertilizer. In addition to the poor spreadability of the product, the fertilizer becomes dangerous since it is no longer protected by the film of the granules. It is therefore important to avoid storing big bags of nitrogen fertilizer in full sun during the summer.


Big bag stockés sous un abri

Most farmers store big bags under cover. This is a good way to avoid fertilizer degradation but it is not enough: the shelter must allow good air circulation, the big-bags positioned on pallets to isolate them from soil moisture and positioned in a pyramid and staggered. For outdoor storage, Yara advises to store them also on clean pallets without spikes, and to cover the stock with a clear tarpaulin (to limit heat accumulation under the tarpaulin). It is strongly advised to opt for outdoor storage only temporarily, either before storage under cover or for very short term use.

If the fertilizer is delivered in bulk, it should be stored in a dry, clean box in a watertight building and covered with a tarp.

Ammonium nitrate fertilizer is not flammable, under normal conditions of pressure, temperature and when not contaminated, the fertilizer is stable. However, it is important to make sure that the big-bags are not close to combustible materials: straw, seed bags, sawdust, wooden pallets, fuel tanks, oil cans, etc. or agricultural machinery. Fertilizer does not burn, but in case of fire, the proximity of a heat source will cause the big-bags to rise in temperature, provoking a thermal decomposition reaction (smoke and toxic gases that should not be inhaled). High dosage nitrogen fertilizers (N>28) present a risk of detonation under very rare conditions.