Crescimento e produção do algodoeiro fertirrigado com àgua residuária sanitária no semiárido de Minas Gerais

Abstract

Most Brazilian municipalities do not have appropriate wastewater treatment systems, with discharge into rivers, degrading quality of surface water. Furthermore, most rural communities do not have sewage treatment systems, generating effluents with potential agricultural use. Thus, we assessed growth and yield of cotton fertigated with different doses of raw sanitary wastewater (ARB) and effluent of tertiary treatment (ART), to supply potassium topdressing according to reference dose of 40 kg K2O ha-1. The field experiment in randomized blocks and split-plot in time design with four replications was used with five treatments (control: Clean water and mineral fertilizer; 100% and 150% of potassium reference dose in topdressing by ARB or ART application) and four evaluation times in subplots. The two wastewater sources meet the potassium topdressing requirements without any effect on stem diameter, leaf number, crown diameter and cotton height, or yield. The highest cotton yield was promoted by 150% of the potassium reference dose in topdressing with raw wastewater.