Laura Eleanor Collazos Rivera, Alberto Mario Arroyo Avilez and Edgar Hincapié Gómez
Centro de Investigación de la Caña de Azúcar de Colombia (Cenicaña), km 26 vía Florida-Cali, Florida, Valle del Cauca, Colombia; lecollazos@cenicana.org
In Colombia’s Cauca River valley, sugarcane is mainly grown in dry to semi-dry environment, making irrigation necessary to avoid water stress that reduces crop productivity. This study evaluated the effects of four different sources of water for irrigation (river water, well water, non-treated water from wastewater treatment plants (WWTPs) and treated water from WWTPs) on sugarcane productivity and the concentration of nutrients and heavy metals in both the soil and the crop. The experiment was carried out with sugarcane variety CC 05-430 in greenhouse conditions at the experimental station of the Colombian Sugarcane Research Center with a randomized complet- block experimental design with four treatments of five replicates each. Average productivity values were 82 t/ha, with no significant differences among treatments. Soil analyses showed that the electrical conductivity values were less than 2 mS/m, indicating that there is no risk of salinity. Heavy metals in soil showed values of 9 mg/kg Pb, 61.79 mg/kg for Cr, 0.12 mg/kg for Cd, 1.88 mg/kg for As, and 0.04 mg/kg for Hg, all below levels recommended by FAO. Soil analyses showed values of 2.2% OM, 52.7 mg/kg P, and 0.27 meq/100g K, ranking between intermediate and high. In the case of P, there was a significant difference (p < 0.005) between irrigated with non-treated and treated WWTP water. Leaf-tissue analyses showed values of 1.13% N, 0.14% P and 1.8% K, considered optimal or very close to optimal for this variety. Levels of heavy metals were low. Results indicated that the use of water from WWTPs can be beneficial for sugarcane productivity, provided that heavy metals in soil and plants are monitored. This study serves as the basis for further research on the sustainability of wastewater irrigation.