Development of materials containing macro and micronutrients for programmed release: sustainable agriculture

Author(s)

Camila Gruber Chiaregato

• Document type: Master's Dissertation
• Press: Pirassununga.
• Institution: Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT)
• Defense date: 2021-08-06

Examining board members

Roselena Faez; Izabela Dutra Alvim; Sandra Andrea Cruz

• Advisor: Roselena Faez

Abstract

Encouraging the development of sustainable agriculture is very important to reduce the negative impacts of excessive land use. Thus, using materials with improved efficiency, which delays the nutrient release, and sustainable policies can contribute to achieving agriculture with less environmental impact. Multilayer films composed of external Macro films and an internal Micro film constituted the Multi-material, with macro and micronutrients. It is interesting to use green processes and biodegradable materials to obtain these materials. From this premise, the objective was to develop materials with macro and micronutrients by two different techniques: (i) Spray-drying, obtaining corn starch microspheres loaded with micronutrients (Mn, Fe, Cu) and (ii) Thermal processing in a mixing chamber, obtaining composites containing microspheres (Micro) or macronutrients (K, N) (Macro) incorporated into a plasticized Poly (vinyl alcohol) matrix. We optimized both used processes to obtain these materials. The materials were characterized thermally (TGA, DSC), structural (FTIR, DRX), and morphologically (MEV), and the release in water and soil were evaluated. Microspheres with different micronutrients showed a distinct release profile in the water. The larger the particle size, the greater the swelling and the slower the release. For Macro, Micro, and Multi composites, the release of micronutrients was more prolonged when first encapsulated by starch. In the presence of micronutrients (Multi), the macronutrients presented a more prolonged release compared to the Macro formulation. The nutrients released in soil depend on the type of formulation, nutrients present. TDR results and soil solution extraction showed that micronutrients interacted more with the soil, mainly for Basacote and Multi/M materials, leaching less. On the other hand, macronutrients are released faster for Bascote and Multi/M materials, as they interacted less with the soil than the Macro formulation. The Multi/M formulation presented a release profile similar to the commercial material Basacote, which demonstrates the material\'s potential for application as EEFs and is based on materials that biodegrade. (AU)

• FAPESP's process: 19/02793-4 - Development of materials containing macro and micronutrients for programmed release: sustainable agriculture
• Grantee: Camila Gruber Chiaregato
• Support Opportunities: Scholarships in Brazil - Master