ABSTRACT
The major nutrients required by plants are nitrogen, phosphorus, potassium. Compound fertilizers are those that supply two or more of the nutrients nitrogen, phosphorus and potassium. The nutrient content expressed as for straight fertilizers is, by convention, written on the bag in the order nitrogen, phosphorus, potassium. The fertilizer applications required to produce the desired plant growth vary according to the type of plant, season of growth, climate of the site, other sources of nutrients applied and the nutrient status of the soil. The mineral levels in the soil change because they are being lost through plant uptake, leaching and fixation, and gained by the weathering of clay, mineralization of organic matter along with any addition of lime and fertilizers. Applications of organic manures or ammonium fertilizers should be delayed until lime has been incorporated. If mixed, they react to release ammonia, which can be wasteful and sometimes harmful.
