Organic manures

There are many benefits to be gained from the application of organic manures to tillage crops.  They provide a valuable source of N, P, K, Mg, S, Ca & minor nutrients such as Cu, Mn & Zn.  These nutrients are supplied in a form that is plant available but also in organic forms that will mineralise over time and provide a reserve of nutrients within the soil.  The nutrient content of organic fertilisers can vary considerably and is affected by the animal type, the diet fed, the bedding material and the extent of dilution with water. 

Organic manures also help to build the soil organic matter and organic carbon which improves the soil health and resilience. The organic matter contents varies depending on the type of manure applied.  For example, low dry matter liquid manures (pig slurry) will not supply as much organic matter/carbon compared to a high dry matter manure such as FYM or spent mushroom compost.

When working with organic manures it is advisable to have the manure analysed to determine the nutrient values based on their percent dry matter (%DM).  For example, there are fresh organic manure products coming from poultry manure and their nutrient values are reported on a fresh weight basis.  In addition, there are poultry manures that are dried and therefore the final nutrient values will be higher compared to the fresh manures.  This can be confusing when values are compared to standard / typical organic manure values as reported in this report.  Therefore, check manure analysis and dry matter % to ensure application rates are adjusted based on the product been applied.  

Current fertiliser prices dictate organic manures offer savings in chemical fertiliser costs. For example an application of 25 m³/ha of cattle slurry can reduce costs by €150/ha in N, P & K.

  Please create an account to view hidden content