Impacts caused by the addition of wine vinasse on some chemical and mineralogical properties of a Luvisol and a Vertisol in La Mancha (Central Spain)

Background, aim, and scope Using wastewaters from wine production that are often discharged directly into soil, with previous treatment, we carried out an experiment to identify the impact over time, specifically to identify the benefits and risks of its application. Materials and methods Experiments were carried out using approximately 200 g of samples of agricultural soils which were amended with increased amounts of vinasse: 1-5-10-20-40-70 ml. The doses used were not arbitrary but similar to the usual one amended. Soil electric conductivity was determined in distilled water with a glass electrode (soil to H₂O ratio 1:5). Clay identification of soil samples are by X-ray diffraction. Results The pH decreased slightly and salinity increased, possibly leading to changes in crop productivity. The increase in salinity reflects the concentration of dissolved salts in the vinasse. Significant changes were observed in the clay minerals after amendment with the vinasse. Conclusions Our study indicates that, under experimental incubation, the application of increasing doses of wine vinasse for increasingly long periods can affect certain chemical properties. The results show that application of winery wastewaters to soil results in significant increases of electrical conductivity, reaching levels that can be detrimental to crop growth. The decrease in pH values is somehow beneficial, and finally there is a small increase in the chemical weathering of clay minerals