Natural fertilisers are solid manure, poultry manure, slurry, and liquid manure.
Natural fertilisers are fertilisers derived from livestock: farmyard manure, slurry, bird manure, intended for agricultural use, including in processed form:
(a) natural liquid manure:
– manure – a mixture of animal faeces and urine with an admixture of water,
– slurry – manure leachate (fermented animal urine),
(b) natural solid manure:
– manure – a mixture of animal faeces and urine with bedding, especially straw, sawdust, or bark,
– avian manure – poultry manure from non-cage systems for keeping the animals.

The beneficial effect of these fertilisers on soil and plants is well known and has been confirmed by many years of scientific research. They contain a whole range of macro- and microelements essential for plant nutrition. Thus their application makes it possible to reduce the use of mineral fertilisers significantly. Manure is also a rich source of organic matter. Natural fertilisers enhance the microbiological activity of the soil and have a comprehensive effect on its fertility.
However, rational manure management is not accessible due to the risk of nitrogen losses. The most critical moment is fertilisers’ application, when significant nitrogen losses in the form of ammonia may occur. Therefore, this treatment must be carried out very efficiently, and the fertilisers must be quickly covered with soil to minimise the loss of this valuable component. The difficulty with manure is that it is dominated by organic nitrogen compounds, which must be converted to mineral forms to make them available to plants. Mineralisation of organic compounds is a long-term process. Therefore nitrogen from manure is best utilised by plants with an extended vegetation period, which should be borne in mind when drawing up fertilisation plans.
The use and storage of natural fertilisers are regulated by the Regulation of the Council of Ministers on adopting a programme of measures to reduce pollution of waters with nitrates from agricultural sources and prevent further pollution of 12 February 2020. (Journal of Laws of 2020, item 243) link to the regulation