Sugarcane yield and quality under irrigation with sewage treatment plant effluent

Abstract

The objective of this work was to evaluate the productive and qualitative performance of sugarcane (Saccharum spp.) irrigated by subsurface chip irrigation with sewage treatment plant effluent (STPE). Irrigation depths were tested between 0% (control, without irrigation) and 200% of crop maximum evapotranspiration, in two ratoon cycles fertilized with half the recommended amount of nitrogen (N). The productivity, in each cycle, was fitted to a model which considers the plant yield as covariable. By this model, productivity gains provided by the replacement of crop evapotranspiration by the irrigation with STPE were: 17.3 and 25.76 Mg ha^-1. The 200% STPE application resulted in a estimated gain of 19.84 Mg ha^-1 at the fisrt ratoon cycle and of 40.47 Mg ha^-1 at the second. Soluble solids were reduced in sugarcane juice with the irrigation use in the first ratoon cycle. However, other industrial quality parameters were not significantly affected by irrigation. The irrigation with STPE promotes sugarcane productivity and reduces the N fertilization requirement of the first and second ratoon cycle.