Soil chemical characteristics, yield and technological quality of sugarcane under subsurface drip irrigation with treated sewage effluent

Sugarcane cultivation requires sustainable strategies to meet water and nutritional needs. This study tested the hypothesis that irrigation with treated sewage effluent (TSE) can meet the water needs of sugarcane plants, improving their technological quality and yield. The objective of this study was to assess the effects of subsurface drip irrigation (SDI) with TSE or surface reservoir water (SRW) on soil chemical characteristics and technological quality and productivity. Thus, an SDI system was installed at soil depths of 0.20 and 0.40 m to apply SRW and TSE to sugarcane plants, composing four irrigation treatments (TSE0.2 m, TSE0.4 m, SRW0.2 m and SRW0.4 m) and a control (non-irrigated treatment). Analyses of soil chemical characteristics in different layers showed no negative effects for the use of SDI, which maintained favorable soil conditions for sugarcane plantations. The surface layer (0-0.2 m) irrigated with SRW or TSE showed higher accumulation of nutrients and organic matter. The results confirmed the hypothesis that irrigation with TSE or SRW improves the technological quality and yield of sugarcane; the treatment TSE0.2 m showed the best results regarding increases in sugar yield and alcohol production. However, continuous monitoring of soil salinity is necessary in wastewater-irrigated agricultural systems.