Effects of a vermicompost composted with beet vinasse on soil properties, soil losses and soil restoration

The use of organic rich wastes instead or as a complement of mineral fertilizers is considered a good environmental practice, provided that the organic wastes are not severely polluted (e.g. occurrence of heavy metals, organic pollutants and/or pathogens). However, the effect of a particular organic waste on soil properties, soil loss and soil restoration depends on its chemical composition. In particular, the application of fresh beet vinasse showed a detrimental impact on the soilʹs physical, chemical and biological properties, increasing soil loss and decreasing plant cover, probably because it contains high quantities of monovalent cations, such as Na+, which destabilize the soil structure. The main objective of this work was to study the effect of beet vinasse co-composted with a vermicompost (constituted by green forages) at rates of 5 and 10 t kg organic matter ha− 1, on physical (structural stability and bulk density), chemical (exchangeable sodium percentage) and biological (soil microbial biomass-C, soil respiration and soil enzymatic activities) properties of soils and, consequently, how its application may contribute to soil loss and soil restoration. The experiment was carried out for three years on a Xerollic Calciorthid located near Seville (Guadalquivir Valley, Andalusia, Spain). The co-composting of beet vinasse and green waste vermicompost had a positive effect on the soilʹs physical, chemical and biological properties, leading to a decrease in soil loss (31.2% compared with unamended soil) and an increase in plant cover (68.7% compared with unamended soil). These results suggest that the co-composting of beet vinasse with vermicomposts protects the soil and contributes to its restoration, thus representing a good strategy for recovering semiarid areas.