Organic Amendment Based on Fresh and Composted Beet Vinasse

Abstract

Industry byproducts present an alternative to inorganic fertilizer use. Fresh and composted organic wastes (non‐depotassified beet [Beta vulgaris L. subsp. Vulgaris] vinasse [BV]compost, BV, and a cotton gin crushed compost [CGCC], which was also included as structural agent in the first compost) were applied for 4 yr to a Typic Xerofluvent in dryland conditions near Sevilla (Guadalquivir Valley, Andalusia, Spain). The effect on the soil's physical properties, soil microbial biomass, and five soil enzymatic activities (dehydrogenase activity, protease activity, β‐glucosidase activity, arylsulfatase activity, and phosphatase activity) and the yield parameters of wheat (Triticum aestivum cv. Cajeme) were determined. Organic wastes were applied at 5, 7.5, and 10 Mg organic matter ha−1 rates, respectively. The application of fresh BV had a detrimental impact on the soil's physical (structural stability, bulk density), chemical (exchangeable sodium percentage), and biological (microbial biomass, soil respiration, and enzymatic activities) properties and the wheat yield parameters, probably because high quantities of monovalent cations, such as Na, and fulvic acids were introduced into the soil by the vinasse, thus destabilizing its structure. However when non‐depotassified BV was co‐composted with a CGCC, the resulting compost had a positive effect on the physical, chemical, and biological properties of the soil. The application of fresh BV resulted in a significant decrease in wheat yield (30% after 4 yr when compared with composted BV.