The application of different organic matter sources as soil amendments is a common practice to stimulate root development and soil quality to improve crop yield and quality. For evaluating the effect of organic amendments on soil quality indicators and agronomic variables in table grape (Vitis vitifera) var Thompson seedless, different treatments including compost from grape pomace, humic extract, microbial inoculant, and chemical NPK fertilization, were evaluated in a pot experiment using an

more »

... ceptisol soil. Organic materials were applied in four C rates: compost, 0, 125, 250 y 500 g C pot -1 ; humic extract, 0, 25, 50 and 100 g C pot -1 ; compost and humic extract at their maximum C rates were also evaluated in absence of chemical fertilization, and microbial inoculant as bio-stimulant. Results showed a stronger root development in plants with compost and inoculant application. Furthermore, organic matter mineralization increased nutrient availability; this was evidenced by an increment of enzymatic activities, particularly β-glucosidase, acid phosphatase, and alkaline phosphatase, in all treatments receiving compost. On the other hand, the application of humic extract produced a larger increment in WSC per carbon unit applied compared to compost, meaning that the former would be more efficient than the latter to provide C for soil microorganisms. This study showed that the joint application of compost, mineral fertilizer, and microbial inoculant should be considered to improve root development in Table grape (Vitis vinifera L.) and soil quality, under Integrated Nutrient Management (INM) programs.