Plant growth and enzyme activities of sunflower seedlings under drought stress cultivated with industrial waste in different particle sizes

Abstract

The reuse of industrial waste from different processes, such as fertilizer or mineral supplement constitute sustainable disposal alternatives. Therefore, the present study aimed to evaluate the effects of using Animal Supplement Residue (RSA) in different granulometries as a component of the substrate of sunflower seedlings submitted to drought stress conditions. To obtain different particle sizes, four sieves with stainless steel mesh were used: 1 mm; 0.500 mm; 0.250 mm and 0.105 mm. The experimental design was completely randomized arranged in a factorial arrangement 2x6, being two water treatments (with and without irrigation for 3 days) and six types of substrates: (1: 100% in volume of sand; 2: Sand + commercial humus at 100% of the recommendation of 80 kg of N ha-1; 3: Sand + RSA 1 mm; 4: Sand + RSA 0.500 mm; 5: Sand + RSA 0.250 mm and 6: Sand + RSA 0.105 mm). Evaluating the growth variables (dry mass of the aerial part, of the root and total), as well as, measuring up the activities of the antioxidative enzymes [Catalase (CAT), Ascorbate Peroxidase (APX), Guaiacol Peroxidase (GPX) and Superoxide Dismutase (SOD)]. The use of animal supplement residue (RSA), with granulometry of 0.500 mm in soil fertilization, promotes the minimization of environmental impacts generated by inadequate disposal and causes cost reduction with traditional fertilization.