This study evaluated potential risk of vinasse to provoke salinity and sodicity in groundwater in a lowland area under sugarcane crop. The research was carried out in Pernambuco State, in the Northeast of Brazil, from December 2010 to September 2011. A georeferenced grid of 81 wells over 7.5 ha (three subareas with 2.5 ha each) under sugarcane crop was monitored. Vinasse was applied at three rates 50, 60 and 65 m³ ha-1 from molasses fermentation. Quality of groundwater was monitored through six samples along period of plant growing. EC, pH, Na+, Ca2+, Mg2+ and SAR were measured. Rate up to 65 m³ ha-1, in lowland areas, for the variables analysed, provided no risk to groundwater for salinity and sodicity, as well as EC and SAR for salinity and sodicity during the experimental stage. This study showed that rainfall provided reduction of salt concentrations in groundwater under monitoring along the time.
Saccharum spp.; residue; subsurface water; rate; rainfall
