The most commonly used biological fertilizer which is used for several years and is considered the best biological fertilizer is animal manure. Production, transportation, and processing of this biological fertilizer are eco-friendly and cost very little to the farmer.
It adds organic matter to the soil and its composition is between 20 to 40%. Moreover, it has effects on the physicochemical stability of soils, plant growth, and development of beneficial microbial populations because of its high proportion of nitrogen and potassium, medium proportions of calcium, and low proportion of magnesium.
It is advised to use a thin layer over a large proportion of land rather than stacking it on a small portion of land.