Nutrient Management

Storage and disposal of organic fertilisers

Organic zoonotic fertilisers are produced throughout the rearing of the animals and are only recommended and feasible at certain times of the year. Therefore, all natural fertilisers need to be stored. Manure should not be stored in field piles, as this leads to groundwater contamination with nitrogen and phosphorus compounds and overfertilisation of the soil under the pile.

The Law on Fertilisers in Article 25. 1. indicates that manure and slurry shall only be stored in sealed tanks with a capacity to store at least 4 months’ production of this fertiliser. These tanks should be “closed” within the meaning of the building regulations. The requirements for the storage conditions for natural fertilisers are contained in a decree of the Ministry of the Environment (Journal of Laws 2003.4.44). Admittedly, for agricultural areas not located in OSN areas, there are no legal requirements concerning the storage period of manure, apart from the capacity of the dung slab, but similar rules should be good practice. In OSN areas, this period should be at least 6 months for both manure and slurry. When calculating the required capacity of organic manure storage areas, the number of animals expressed in livestock units (LUs) should be taken into account. The required area of the slurry pad depends on the height of the manure pile. This area is reduced in proportion to the time the animals are on the pasture. The extent of this reduction and other factors are available in the literature. Detailed regulations with the method of calculation for individual animal species are contained in Journal of Laws 2018, 1339.

Composts do not have specific regulations for their storage.

Organic fertilisers contain all the macro- and micronutrients that are essential for plants, which are released by the mineralisation processes of the organic compounds they contain. In order to carry out rational and lawful fertilisation, it is necessary to know the exact nutrient content of the fertiliser used. For mineral fertilisers, these values are known and contained in the fertiliser application instructions. For organic fertilisers, only the standard values that are available in the literature are known. The standard values are indicative and the actual nutrient content may vary depending on the source of such fertiliser. During storage of organic fertilisers, chemical transformations take place in them leading to losses of some components through volatilisation or leaching. Therefore, their composition should be verified for a specific batch of fertiliser and the time and conditions of storage. Knowledge of the chemical composition of a particular fertiliser enables optimum fertiliser application rates to be set and over-fertilisation or environmental pollution to be prevented. We can have the composition tested by a district chemical and agricultural station or by another laboratory that performs such tests (WIOŚ). The samples should be representative of the whole batch of material tested. Instructions for collecting manure, slurry and compost can be found on this page.