Crescimento do milho (Zea mays L.) em substratos produzidos a partir de resíduos de indústria farmoquímica

Abstract

Brazil produces approximately 242,000 tons of residues per day, being 76 t deposited in open sky and only 0.9% is recycled, including composting. Composting in Brazil is little used as a recycling strategy, but can be a solution for many residues. The pharmochemistry industry Solabiá Ltda. located in the district of Floriano, City of Maringá - Paraná - Brazil, generates hazardous residues in the condroitin sulphate production. Amongst other materials, the industry produces organic (Animal Cartilage) and inorganic residues (Perlite). These materials, after being processed, and with others, can form a soil less media for plants. The objectives of this work were to evaluate the chemical and physical attributes of soil less media produced from the composting of these residues with other organic materials and their effect in the maize dry matter. In order to attain these objectives two sets of experiments were organized. The first one was composed of seven composting units where was mixed, in different ratios and combinations: Sugar Cane Bagasse (BC), Bovine Manure (EB), Animal Cartilage (CA), Basalt Rock (BA), Perlite (DC), and Sand (AR), in plastic vials of 22 liters. After the composting process was carried, the soil less media produced was characterized in their chemical and physical attributes. In the second experiment, 1 liter of composted soil less media was used to evaluate the maize dry matter production. The experiment was completely randomized design with four repetitions and the seven produced soil less media. Beyond these, two other soil less media were also evaluated: Earthworm Humus and Plantmax®, where two plants of maize per vase were culativated. Fifty days after the germination, the plants were cut and evaluated the following morphometric attributes: plant size, number of leaves, maize dry matter weight of the aerial part, root, and total. The analysis of the results of the chemical attributes showed, respectively, that the Animal Cartilage and the Perlita are good components for the formation of soil less media for favoring some chemical (P, Ca, etc) and physical (density) attributes. The soil less media that received Basalt Rock presented great difficulties for the development of the plant in function of its physical and chemical attributes, such as the high electric conductivity found in the different substrates is due to the adition of NaCl and NaOH to the industrial processing of the Animal Cartilage. The substrate formed from BC+EB, BC+EB+CA; BC+EB+CA+DC, BC+EB+CA+AR and EB+CA, presented intermediate chemical and physical attributes that resulted in the biggest maize dry matter production.