Influence of soil management in viticulture on ecosystem services related to meso-and microfauna
Abstract
Suppression of the inter-row permanent ground cover sward by tillage or herbicide strongly affected ecosystem services in McLaren Vale Shiraz. Ground cover suppression increased yield (berry size) by 15% (0-40%) due to increased nitrogen availability. Overall water stress (measured as must δ13C) was not significantly affected but was related to Leaf Area Index. Soil Organic Matter (SOM), entomopathogens and seed predation were unchanged. SOM decomposition and meso-fauna abundance increased in tillage while bulk density and compaction decreased. Arthropod biodiversity was highest in Sward. Optimising soil management requires variation over time to conciliate long term positive and negative impacts, increasing resilience for the grower. A three year collaborative project including winter cover crops and more regions is in preparation.
Summary
In viticulture, a perennial cropping system, sustainable soil management is of major importance to maintain production quantity, quality and regularity over the life-span of a vineyard block. Vineyards are often established on agronomically ‘marginal’ soils that allow production of good quality grapes for wine making, limiting rather than maximizing yield in order to increase the quality of the grapes and the wine. This also implies a risk that such marginal parameters will evolve over time to unfavourable conditions and a negative impact on production. Different soil management options are available for -and used by- grape growers: Ground cover (natural or sown, permanent or not), herbicide applications, tillage or a combination of these. Growers often tend to opt for a single strategy in a block and maintain it over many years. However, over time a chosen soil management practise can also show adverse effects, such as too much or not enough competition, or a decrease in soil organic matter (SOM), leading to a shift in plant performance. The use of a permanent sward (ground cover) is the most frequently chosen option in the McLaren Vale region and this has a number of advantages, such as improving soil strength, but also imposes risks, such as strong competition with grapevines, that are not always well recognized by growers and consultants. In this experiment we quantified the effects of the suppression of the sward by tillage or herbicide application on provisioning (yield, plant growth), supporting (soil organic matter, soil fertility) and regulating (seed predation, soil organic matter degradation) ecosystem services. We also determined the effects of these practices on a number of potential ‘service providers’ i.e. organisms involved in these processes (soil arthropods, nematodes, micro-organisms). In such an ‘Agro-Ecology’ approach, we were primarily interested in interactions between different factors.