Evaluation of new environmental friendly particulate soil fertilizers based on agroindustry wastes biopolymers and sugarcane vinasse

摘要

This study evaluated the physicochemical and morphological properties of pectin and chitosan particles combined with sugarcane vinasse for soil fertilization applications. Particles were obtained by adding the biopolymeric solutions (pectin or chitosan solution) dropwise into the crosslinking solutions (calcium chloride 1% in ethanolic solution or tripolyphosphate 5% aqueous solution) followed by drying. Vinasse enhanced pectin gel stability improving pectin/vinasse particle properties. Physicochemical characterization indicated that vinasse nutrients were properly incorporated in both pectin and chitosan matrices. Particles showed spherical shape, with an average diameter of 3 and 2 mm for the pectin and chitosan particles with vinasse, respectively. Chitosan particles, compared to pectin, showed lower swelling capacity and solubility and higher mechanical resistance indicating a denser and more compact polymer network. Both particles were able to hinder water evaporation rates from sandy soil under water stress conditions. Biobased particles with vinasse added show potential to be applied as soil fertilizer representing an alternative to use and disposal of this expressive wastewater from sugar and alcohol industries.