Intensive livestock production and the resulting overuse or misuse of naturalfertilisers, mainly slurry, contributes to chemical and biologicaldegradation, erosion and reduced fertility of arable land.
Itis particularly dangerous to spread slurry directly on soils of smallair capacity during the period of plant vegetation. Soil salinity andelevated nitrate levels, acute oxygen deficiency in the rhizospherecaused by intensification of biochemical reactions, increased humidityand oxygen consumption by plant roots are the likely consequences.Oxygen depletion in soil inhibits the growth of plant roots, which areable to absorb limited amounts of nutrients and water. Anotherconsequence of oxygen deficit is the increased proliferation ofanaerobic microorganisms and facultative aerobic microorganisms whichconsume oxygen from chemical compounds. As a result, the released ironand manganese can react with other elements to create compounds whichare toxic to higher plants.
Slurryis a source of excessive volumes of chemical compounds which decomposeeasily, leaving excess energy and higher demand for inorganic ions amongsoil microorganisms, which can exceed the mineralization capacity ofsoil. Excess ions are metabolized and immobilized in soil, whichsignificantly restricts access to nutrients which can be easily absorbedby crops.
Ifslurry is injected directly into soil, it can be contaminated withparasites and pathogen. If the fertilisation is particularly intensive,humus levels in the soil may be unintentionally decreased.