Irrigation with Wastewater and K Fertilization Ensure the Yield and Quality of Coloured Cotton in a Semiarid Climate

Treated domestic sewage (TDS) can contribute to plant nutrition and improve crop production. However, there are no data for its use in coloured cotton under a deficit or excess irrigation combination with potassium fertilization rates (KRs), mainly semiarid tropical conditions. The research was conducted using randomized complete block design factorial scheme (5 × 5, regimes vs. rates), plus an additional treatment as the control ((5 5) + 1). treatments consisted of five TDS (50, 75, 100, 125, 150% evapotranspiration—ETC) KRs (0, 50, 150, 200% local recommendation), control—CT— (irrigated fresh water at 100% ETC fertilized according recommendation) four replications. optimal yield, efficiency, efficiency were obtained when applied 75% full (100% ETC) associated moderate increases K fertilization. These also resulted better fibre quality compared CT, meeting exceeding requirements textile industry. Therefore, is indicated important strategy save reduce fertilizers, while having potential increase profit margins production regions.