THE POTASSIUM RATE INFLUENCE ON PERCOLATED WATER BY USE OF PURE VINASSE AND TREATED ALKALINE PROCESSES AS AGRICULTURAL FERTILIZER

The vinasse can be considered the main wastes of the sugar and alcohol industry, being produced thirteen times more than the ethanol. Today, this wastes is deposal in soils, because according to studies the vinasse promotes... [ view full abstract ]

The vinasse can be considered the main wastes of the sugar and alcohol industry, being produced thirteen times more than the ethanol. Today, this wastes is deposal in soils, because according to studies the vinasse promotes the increase of the fertility of the soil when applied respecting the retention capacity of ions. If this capacity is not respected, the process of leaching of several of these ions, especially potassium, can be move to the sub-surface water. Our objective was evaluate the presence of potassium in the percolated water and the contamination possibilities of this element resulting from the addition of different forms of vinasse on the soil surfasse as a fertilizer. The vinasse was used under four differents forms, beeng a pure vinasse, three kinds of vinasse treated by the alcaline processes and one more tratmente as a comercial fertilizer made with N, P and K . That three kinds of vinasse treted by the alkaline processes, the first consist only of the alkalinization of the vinasse by the addition of alkaline material until the mixture reached pH 12. The others two kinds consist in a incorporation of ash boiler, another wastes from the ethanol manufacturing process. In this case, the decrease of the moisture content and subsequent adjustment of the pH with the addition of alkaline material in different proportions. The treatments were applied on the surface and in each column was cultivated wheat (Triticum aestivum). For 70 days, distilled water was added as controlled irrigation, and the volume recorded was recorded in order to guarantee that all the material percolated and resulted only from the treatments. Each treatment received the next volumes: vinasse, 25m³ * ha ^-1; Vinasse pH12, 10m³ * ha ^-1; Treated vinasse + ash + 25% alkalisizer, 8m³ * ha ^-1 and treated vinasse + ash + 50% alkalizing, 6m³ * ha ^-1. It should be noted that the volume of vinasse applied was based on the values allowed by the Brazilian standard and the other treatments based on the soil need. It was observed that at thirty-five days of percolation the potassium content in the water reached the maximum value of 1.0 ml.ha ^-1 for comercial fertilizer (NPK) treatments, vinasse + ash + 50%, vinasse + ash + 25% and vinasse pH12. It was concluded that the alkalized vinasse can influence the potassium contents present in the superficial water percolated after 35 days of its superficial application to the soil.

KEY WORDS: Agricultural wastes; Sustainability; ethanol industry