Vinasse for sugarcane crop nutrition: accumulation and efficiency in the use of nutrients

The use of agro-industrial by-products such as biofertilizers hinders polluting discharges and allows savings commercial fertilizers. The application of vinasse (a by-product of ethanol manufacture) in sugarcane (Saccharum officinarum) production was evaluated in two soils of Uruguay (L1 and LB2). In a first ratoon crop, 150 and 300 m3 ha-1 of vinasse were applied (V150 and V300) and compared with the application of fertilizer (F) and a Control (C) with no application. Then, production and the plant’s N, P, K, Ca and Mg contents were determined. Vinasse and fertilizer applications increased sugarcane growth, as compared to C. However, there were no differences between vinasse dosses. The L1 fertilization treatment produced higher stem yield than vinasse application, whereas LB2 caused no differences. The application of vinasse at LB2 and L1 increased K uptake, exceeding the control, by 151 and 133 kg ha-1 of K, respectively, indicating that it could substitute fertilizer, while supplemental nitrogen fertilization would be required for maximum yield. The low use-efficiency of potassium (K) in vinasse treatments suggests that there was excessive consumption. Although vinasse increased soil exchangeable K, its residual effect would be insufficient for the second ratoon harvest, requiring annual applications