Treated Dairy Wastewater Effect on the Yield and Quality of Drip Irrigated Table Beet

Abstract.

This study was conducted to evaluate the level of total soluble solids and the yield of the table beet irrigated with dairy-treated effluent at different irrigation depths. The experiment was conducted in a greenhouse (210 m²) near the dairy effluent treatment plant of the University of São Paulo, located at Pirassununga, Brazil. The treatments consisted of three types of water: (1) Anaerobic Effluent – ANE, (2) Aerobic Effluent – AE, and (3) Tap water – TW. Three different irrigation depths were used aiming the replacement of 50%, 100%, and 150% of the estimated crop evapotranspiration (ETc). All these treatments were applied in combination with 50% of the nitrogen fertilization recommended for the table beet. Apart from these, there was a control (table beet with 100% of the nitrogen fertilization requirement and irrigation depth equal to 100% of the ETc). The use of wastewater and the higher irrigation depths promoted differences in the evaluated parameters. It was possible to observe that the table beet development was most favorable when irrigated with ANE and AE. The irrigation with ANE resulted in better yields at all irrigation depths compared to other treatments (AE and TW). This indicates the importance of differentiating the source of available nutrients (particularly nitrogen) in the wastewater. The use of rising irrigation depths with treated dairy wastewater caused an increase in the beet root mass. In this way, the level of the total soluble solids in the root of the table beet was decreased; nevertheless, the obtained values did not reduce the table beet quality.