Chapter 3 - Controlled release of fertilizers—concept, reality, and mechanism

Abstract

Controlled release fertilizers (CRFs) are fertilizers that release nutrients in a controlled manner to satisfy the nutrient uptake of a crop. CRFs increase crop production, reduce plant toxicity and stress, and reduce soil, water, and atmospheric pollution. Fertilizer burn is not a problem with CRFs, and it also reduces nutrient loss by leaching and runoff. This technology provides a scientific method to improve the performance and safety of chemicals by using barriers surrounding the active materials in a prill form ensuring delivery at an optimum time. Overuse of phosphatic and nitrogenous fertilizers leads to eutrophication in aquatic ecosystems, crop damage, and environmental problems. CRFs provide a promising alternative for improving the management of nutrient supply and decreasing environmental pollution while maintaining good quality and high crop yields. Nutrients are released in a controlled manner either by releasing nutrients by imperfections in the coating of the prill or the use of uncoated fertilizer prills in the formula. This technology has been tested in a large number of crop plants and obtained good quality yield when compared to conventional fertilizers.