Soil biological activity and nutrient dynamics under contrasting vineyard management systems

ABSTRACT Cultural management practices in vineyards (Vitis spp.) significantly influence soil quality. Nevertheless, the impact of these practices on soil quality within Chile’s heritage vineyards remains largely unexplored. This study sought to assess the effects of two distinct management practices-organic and conventional-on soil quality in vineyards located in the Itata Valley, Ñuble Region. The investigation focused on microbiological variables, including microbial biomass, basal respiration, and enzymatic activities associated with the C, N, P, and S cycles, as well as chemical variables such as pH, organic matter, available nutrients, and total soil trace elements. Additionally, the study examined the influence of varying durations of organic management (2 to 11 yr) on soil quality parameters. Organic management was found to significantly enhance soil biological activity, as indicated by increased basal respiration, microbial biomass, and key enzymatic activities related to the C, N, P, and S cycles, with improvements ranging from two- to 3.2-fold (P < 0.05) compared to conventional management. Conversely, conventionally managed vineyards exhibited higher soil nutrient availability, including nitrate (58%) and sulfate (95%), than their organically managed counterparts. Soil quality has improved with extended periods of organic management. Over the span of 2 to 11 yr of organic management, there were significant increases in pH and Ca (P < 0.05), while Cd levels decreased by 25%. Consequently, organic management is superior for the sustainability of heritage vineyards, as it increases soil biological activity by up to 3.2-fold and reduces heavy metals such as Cd by 25% after 11 years of implementation.