Effect of Different Carbon Rates on Table Grapes ('Thompson Seedless') in a Controlled Experiment

Seedless table grape cultivars, particularly 'Thompson Seedless', represent about 25% of the total area planted and is one of the most important export crops in Chile. This grape is produced in different regions, the Limari Valley-Coquimbo, in the IV region, one of the most important producing regions in the world. Due to low organic matter content in soil and a rainfall regime (approximately 100 mm/year), application of different organic matter (OM) sources, especially goat manure, is a common practice, intended to decrease plant decay and stimulate root development. The main objective of this research was to evaluate the effect of the application of grape pomace compost and humic acids as organic amendments on some soil quality indicators and agronomic variables in table grape, using a randomized experiment with 20 treatments evaluating two organic sources in four C rates (compost from grape pomace, 500, 1000 and 2000 kg C/ha; liquid humic acids, 100, 200 and 400 kg C/ha), in presence and absence of chemical fertilization and commercial microbial inoculants were evaluated. Nutrient availability, microbial populations and enzymatic activities were defined as measured variables. The use of organic matter as source of organic carbon alone or in combination with microbial inoculants will be a proper management for modern horticulture systems, is an integrated form to produce environmentally safe and economically viable.