Soil Management Induced Shifts In Nematode Food Webs Within A Mediterranean Vineyard In The Central Coast Of California (Usa)

The soil food web regulates several key processes that support soil health and agricultural production. Here we investigated how soil management within a commercial Pinot noir Mediterranean vineyard affects nematode abundance and community structure, as a proxy to evaluate the status of the soil food web. We compared the soil under the vine to the soil in the tractor row which receive different water and nutrient inputs and different strategies to manage herbaceous vegetation cover. Furthermore, we compared the effects of different fertilizers (organic, synthetic and no fertilizer) applied under the vine. Our results showed that the soil in the tractor row hosted a more complex food web, with a higher abundance of microbial feeding nematodes and processing of the soil C and organic matter through omnivore and bacterivore nematodes leading to higher amounts of plant available N, likely due to increased mineralization rates. Thus, the tractor row has a great value as a reservoir of biodiversity within vineyards and support soil ecosystem services such as C sequestration and N cycling. The soil under the vine was characterized by a higher abundance of herbivore nematodes and high plant parasitic index that were alleviated by the addition of organic fertilizers increasing the abundance of bacterivore and fungivore nematodes, contributing to a more balanced food web. Changes in nematode community composition and food web status were strongly associated to soil physicochemical properties such as the active C, nitrate and soil pH. Thus, a change in fertilizer management could significantly boost soil health in these intensively managed soils.