%0 Journal Article
%T Meticulous Overview on the Controlled Release Fertilizers
%A Siafu Ibahati Sempeho
%A Hee Taik Kim
%A Egid Mubofu
%A Askwar Hilonga
%J Advances in Chemistry
%D 2014
%R 10.1155/2014/363071
%X Owing to the high demand for fertilizer formulations that will exhaust the possibilities of nutrient use efficiency (NUE), regulate fertilizer consumption, and lessen agrophysicochemical properties and environmental adverse effects instigated by conventional nutrient supply to crops, this review recapitulates controlled release fertilizers (CRFs) as a cutting-edge and safe way to supply crops¡¯ nutrients over the conventional ways. Essentially, CRFs entail fertilizer particles intercalated within excipients aiming at reducing the frequency of fertilizer application thereby abating potential adverse effects linked with conventional fertilizer use. Application of nanotechnology and materials engineering in agriculture particularly in the design of CRFs, the distinctions and classification of CRFs, and the economical, agronomical, and environmental aspects of CRFs has been revised putting into account the development and synthesis of CRFs, laboratory CRFs syntheses and testing, and both linear and sigmoid release features of CRF formulations. Methodical account on the mechanism of nutrient release centring on the empirical and mechanistic approaches of predicting nutrient release is given in view of selected mathematical models. Compositions and laboratory preparations of CRFs basing on in situ and graft polymerization are provided alongside the physical methods used in CRFs encapsulation, with an emphasis on the natural polymers, modified clays, and superabsorbent nanocomposite excipients. 1. Introduction Controlled release fertilizers (CRFs) are fertilizer granules intercalated within carrier molecules commonly known as excipients to control nutrients release thereby improving nutrient supply to crops and minimize environmental, ecological, and health hazards [1]. In that sense, CRFs usage is an advanced way to supply crop¡¯s nutrients (cf. conventional ways) due to gradual pattern of nutrient release, which improves fertilizer use efficiency (FUE) [2]. In other words, depending on the thickness of the coatings within the formulation, CRFs enable nutrients to be released over an extended period leading to an increased control over the rate and pattern of release [3], consequently the excipients play a role in regulating nutrients release time and eliminate the need for constant fertilization and higher efficiency rate than conventional soluble fertilizers [1]. Occasionally the terms controlled release fertilizers (CRFs) and slow release fertilizers (SRFs) have been used interchangeably, yet they are different. Typically, the endorsed differences between
%U http://www.hindawi.com/journals/ac/2014/363071/