Controlled-Release NPK Fertilizer Encapsulated by Polymeric Membranes

Abstract

The commercial granular fertilizer NPK6-20-30 was coated using polysulfone (PSF), polyacrylonitrile (PAN), and cellulose acetate (CA). The coatings were formed from the polymer solutions by the phase inversion technique. Measurements of the thickness and porosity of the prepared coatings and a microphotographic observation of the coatings were performed. The physical properties of the coatings influence the release rate of macronutrients which are present in the core of the coated fertilizer. In the case of PAN coating with 60.45% porosity, prepared from a 16% polymer solution, 100% of NH(4)(+) and P(2)O(5) was released after 4 h of test and 99.7% of K(+) after 5 h of test, whereas in the case of coating with 48.8% porosity, 31.8% of NH(4)(+), 16.7% of P(2)O(5), and 11.6% of K(+) was released after 5 h. In all experiments, different selectivities of the coatings in terms of the release of components were observed. The release of potassium through the coatings made of PSF and PAN was the slowest. The same tendency was observed for the release of nitrogen through a coating of CA. The release of fertilizer active components was the slowest in the case of PSF. The lowest porosity coating was prepared from the 18% PSF solution.

Phosphorus use efficiency in maize as a function of different sources

“…Corroborating Jarosiewicz and Tomaszewska (2003), the study by Chagas et al (2016) reported that higher phosphorus accumulation in onion bulb was obtained with the use of polymer-coated triple superphosphate. The source KIM COAT (LGP) presented no difference compared to conventional MAP.…”

“…Gazola et al (2013) points out that in the case of phosphorus, a simple practice such as liming would be effective in reducing its problem of high soil adsorption and slow release fertilizer would not be required for this nutrient. For Jarosiewicz and Tomaszewska (2003) the efficacy of coated fertilizers relies on the solubility of the polymer that coats the granules. Moreover, the thickness and chemical nature of the coating resin, number of surface microcracks and fertilizer granule size determine the rate of nutrient release over time (Girardi and Mourão Filho, 2003).…”

Efeito residual da aplicação de fosfato monoamônio revestido por diferentes polímeros na cultura de milho

“…Isto irá regular o processo de fornecimento dos nutrientes. Essas taxas de liberação e de dissolução de fertilizantes solúveis em água dependem dos materiais de revestimento (Jarosiewicz & Tomaszewska, 2003). Ainda, segundo estes autores, a liberação do nutriente irá depender da temperatura e da umidade do solo.…”

Characterisation and Biodegradation of Poly(Lactic Acid) Blended with Oil Palm Biomass and Fertiliser for Bioplastic Fertiliser Composites

“…The first one involves the mechanism of progressive dissolution to attain slow nutrient release, which can be achieved by synthesising novel compounds with low water solubility (Bhattacharya et al 2007;Bandyopadhyay et al 2008). The second option is to coat the fertilizers with organic materials that have low water solubility (Jarosiewicz and Tomaszewska 2002;Ni et al 2010). The coating allows control over the rate of nutrient release by means of its diffusibility and biodegradability characteristics, depending on the varying physical and chemical properties of the coating material.…”