Híbridos de quitosana-argila para encapsulamento e liberação sustentada do fertilizante nitrato de potássio

Abstract

. The use of controlled release fertilizers is a trend for improving productivity, reducing costs and environmental pollution. Such materials release gradually the nutrients to the plant in order to supply its requirement and are an alternative to improve fertilization. The preparation of a microsphere from natural materials (chitosan and montmorilonite clay) added with nutrients, according to the needs of plants nutritional, is one of the main motivations of this work. The addition of lamellar silicates as natural clays is a promising alternative to increase water and chemical compounds sorption capacity. In the present chitosan/montmorilonite clay composites were prepared via inversion phase and thermal, structural and morphologically studies were performed. The release of the KNO 3 was realized in water using conductimetry and time domain reflectometry technique was used to monitor the in situ release in soil. Double coated microspheres provide the better nutrient encapsulation and a swelling of 200% was observed. The release was influenced by pH and fast release was observed for pH 4 and 5.5. According to the soil tests a slow release was observed since the KNO 3 delivery was accompanied during 60 days showing higher values in the first ten days and a constant value until 60 days.

Controlled-Release Fertiliser and Substrates on Seedling Growth and Quality in Agonandra brasiliensis in Roraima

“…A good substrate with proper handling should be used, together with a quality fertiliser in suitable doses. According to Messa et al (2016), Forth Cote ® , a controlled-release nutrient fertiliser, is often used to produce seedlings in containers. Menegatti et al (2017) report that controlled-release fertiliser provides nutrients to the seedlings continuously and for a longer period, which results in less possibility of nutrient deficiency during the period of seedling formation, dispensing with the split application of other sources, thereby reducing the operating costs of seedling production.…”

Cápsulas de amido/quitosana e quitosana aplicadas no controle da volatilização de nitrogênio / Starch/chitosan capsules and chitosan applied to control nitrogen volatilization

“…A técnica de gotejamento de uma solução polimérica tendo um ativo dissolvido em uma solução que insolubiliza o polímero em meio aquoso é muito utilizada para produzir cápsulas, sendo que as cápsulas formadas apresentam tamanhos de 500 a 1000 mm e autores tem utilizado a técnica para produzir partículas fertilizantes (MESSA et al, 2016, DIAS et al, 2008, CORRADINI et al, 2008 A quitosana pode ser utilizada em sistemas de encapsulamento de ureia para produzir fertilizantes de liberação controlada, sendo um polímero obtido pela desacetilação da quitina que é extraída da carapaça de crustáceos. A quitosana forma gel em solução de ácidos orgânicos como o ácido acético, comportando-se como um hidrogel em meio aquoso, sendo que a solução de hidrogel gotejada em uma solução levemente Brazilian Journal of Development, Curitiba, v.7, n.4, p. 35602-35611 apr 2021 alcalina pode formar cápsulas, imobilizando o ativo em um sistema polimérico não solúvel (MESSA et al, 2016).…”

Microencapsulation of potassium phosphate in chitosan and the effect of spray drying operating variables on the particle size

“…Due to deficient uptake of these chemical fertilizers by plants, the remaining fraction reach into water bodies through rainwater, causing eutrophication and affecting living beings [4]. In recent years, in agriculture there has been a growing interest in the implementation of controlled released fertilizer systems as a promissory alternative to improve the performance of several usage aspects of fertilizers [5].…”