This Draft Uganda Standard specifies requirements, sampling and test methods for organic fertilizers.
Organic fertilizers are naturally available mineral sources that contain moderate amount of plant essential nutrients. They are capable of mitigating problems associated with synthetic fertilizers. They reduce the necessity of repeated application of synthetic fertilizers to maintain soil fertility
Organic fertilizers comprise a variety of plant-derived materials that range from fresh or dried plant material to animal manures and litters to agricultural by-products. The nutrient content of organic fertilizers varies greatly among source materials, and readily biodegradable materials make better nutrient sources. Nitrogen and phosphorus content is lower, often substantially lower, in organic fertilizers compared to chemical fertilizers.
Commonly used organic fertilizers include composted animal manure, compost, sewage sludge, food processing wastes, and municipal biosolids. They improve soil health and release nutrients to soils gradually. Examples of naturally occurring organic fertilizers include manure, slurry, worm castings, peat, seaweed and guano. Green manure crops are also grown to add nutrients to the soil. Naturally, occurring minerals such as mine rock phosphate, sulfate of potash and limestone are also considered as Organic Fertilizers. Examples of manufactured organic fertilizers include compost, blood meal, bone meal and seaweed extracts. Other examples are natural enzyme digested proteins, fishmeal, and feather meal.
Organic fertilizers are considered an excellent source of nutrients, providing plants with vital vitamins, and soil acts as a medium between crops and fertilizers. Fertilizers can be divided into several types, depending on their components, shape, and various other properties.
Meat and bone meal is an industrial by-product obtained by treating animal carcasses with heat, removing the fat, and finally drying and mincing them. Due to the high levels of total nitrogen (8%), phosphorus (5%), and calcium (10%) in meat and bone meal, these organic matters can be considered as useful fertilizers for soil improvement.
Manure is an organic fertilizer used for soil fertilization after animal waste decomposes due to bacteria and fungi. Composting manure takes a relatively long time. This decomposed manure is later used in agriculture to increase and promote soil productivity. Well-decomposed manure contains N (0.5%), P2O5 (0.3%), and K2O (0.5%). Manure is used as a fertilizer, improves soil productivity by providing practically all the elements needed by plants, but not always in the right amounts, and proportions. Slurry and solid manure are traditionally spread directly on the soil surface as fertilizers.
Organic fertilizers are an alternative to minimize the environmental pollution that may be due to excessive use of inorganic fertilizers.
Liquid fertiliser contains nutrient compounds that could be applied as plant enhancer and are used in foliar application, as it does not require soil medium and environmentally friendly. An organic liquid fertilizer can be produced from bio-wastes composting as it contains more organic nutrients that are essential to promote healthy plant growth.