Organic farming has become increasingly popular in all areas of agriculture, including the field of viticulture. In organic viticulture, organic fertilizers and very few non-synthetic pesticides are allowed. Organic farming aims to increase soil biological function by improving its physical, chemical, and biological properties; which includes water circulation and aeration, availability of nutrients, and biodiversity. By improving these properties, soil quality is thus enhanced. In viticulture, the following parameters are measured when determining soil quality: soil bulk density, pH, nutrient availability, organic matter content, and soil water holding capacity. Soil scientists and viticulturists consider soil micro-organisms to be very important indicators of soil health, as these micro-organisms form very close relationships with their surroundings. Micro-organisms in the soil are important for many reasons; decomposition of organic matter, humus formation, nutrient cycling, and symbiotic relationships with other organisms in the soil. Macro-organisms, such as nematodes and earthworms, are also important indicators of soil health. They are present in all types of soil and frequently alter the physical properties of the soil.
In soil, organic matter is a very important component, and is often considered the most important aspect of soil management in farming. Organically managed plots have higher levels of total organic carbon, which indicates high soil quality. This total organic carbon acts as a nutrient resource for micro-organisms, which stimulates microbial growth and increases soil health and quality overall.
There are clear differences in soil quality between conventional and organically managed vineyards over time. During the transition period, between conventional and organically managed plots, there is a decrease in available resources. This is due to exhaustion of the excess nutrients that were created from synthetic fertilizers used under conventional farming practices. Once the microbial community in the soil starts producing their own soil nutrients, (via metabolism) the by-products increase soil carbon supplies, the microbial growth is stimulated, and the overall soil quality is enhanced.