Properties of organic fertilizers

Organic nutrient sources are highly heterogeneous in nature and vary in quality and quantity. The quality aspect is important in order to determining the nutrient release potential of the organic fertilizer. Microorganisms that decompose organic fertilizers uses the carbon in such materials as an energy source for growth. Required even bigger quantity by microorganisms for growth and reproduction of nitrogen. Commonly available materials are often particularly low in nitrogen content. For organic fertilizers with low nitrogen contents (such as cereal straw and most smallholder farmyard manures), microorganisms themselves will consume much of the available nitrogen for their own growth. Consequently, insignificant amounts of nitrogen will be released for the crop. Thus, on their own, poor quality materials have limited potential to enhance productivity. The effectiveness of such materials can be improved by combining them with mineral nitrogen fertilizers such as ammonium-nitrate or urea. Mineral fertilizers may be used more efficiently by crops growing on soils with adequate amounts of soil organic matter that is supplied by organic fertilizers.