Sugarcane production and nutrient accumulation in commercial plantations under vinasse irrigation

Vinasse is a liquid byproduct of ethanol production used as fertilizer for sugarcane (Saccharum officinarum L). Although the nutrient concentration of vinasse is relatively low, it is considered a valuable source of nutrients. Currently, in Uruguay undiluted vinasse is applied in fields close to the ethanol industrial facilities (ALUR, Bella Union), but its effect on soil and crops has been scarcely studied. This work, carried out between 2014 and 2017, evaluated the production and absorption of nutrients in 21 commercial plantations receiving vinasse (doses between 26.5 and 150 m3 ha-1) to assess its contribution to the crop nutrition and sustainability of the production system. In each plantation the production of biomass and content of nutrients were analyzed (N, P, K, Ca, Mg, Na, Cu, Fe, Mn, and Zn). The yield varied from 34.4 to 125.3 Mg ha-1, (average 64.7 Mg ha-1), while average aerial biomass production was 33.1 Mg ha-1 of dry matter. The highest accumulation of nutrients for the crop corresponded to K (average 216, 154 and 157 kg ha-1 in 2015, 2016 and 2017, respectively), which highlights the importance of vinasse as a K source. However, in some fields a low efficiency of K utilization was estimated. It is concluded that the application of vinasse makes an important contribution of nutrients (N, P and K) to the crop, which allows achieving high yields, as well as saving commercial fertilizers.