Healthy soil is fundamental to maintaining a good quality and profitable vineyard. Hutchinsons' Rob Saunders and Dick Neale highlight three key areas to focus on.
Waterlogging is detrimental to any crop and vines are no exception. Saturated soil suffocates roots, reduces vigour, and can increase the risk of diseases such as downy mildew and botrytis. Wet soils are also slower to warm in spring and will hamper harvesting activity in autumn.
Heavy rain last autumn and winter may well have highlighted areas of poor drainage that need addressing, especially on heavier sites without the natural drainage of sloping chalk soils.
Poor-draining areas (often headlands on low-lying areas) should be mapped now as it may be some time before land is dry enough for remedial work, such as subsoiling or installing piped drainage.
Meanwhile, ensure ditches, culverts and existing drains are clear to let water away efficiently.
Protect bare soil
Although some growing systems favour bare soil throughout the year to minimise weed competition and aid ripening, such approaches are tough on soil health, so providing some protection with green cover and/or mulch is preferred.
Low-vigour grass, such as red fescue, sown in alleyways is a cost-effective way of protecting the soil surface and improving the ability to travel, while minimising competition with vines.
Although more expensive to establish than natural regeneration ("tumbledown"), the latter could be costlier longer-term if competitive weed species (e.g. docks, nettles, couch) take over.
Bare soil under vines is still at risk from erosion, capping and poor infiltration, so consider applying organic matter, which can help suppress weeds too.
On fertile soils, opt for material with a high carbon: nitrogen ratio, such as paper crumble (a by-product of paper manufacturing). This is relatively cheap, spreads easily, builds structure, and is long-lasting. With a C:N ratio of 60:1, it can help keep foliar growth in check on fertile soils as microbes consume nitrogen breaking down the carbon. It is also an excellent food source for worms, which benefit natural drainage and nutrient cycling.
Cereal straw (typically 80:1 C:N) and wood chips are other options, although spreading can be trickier.
On thinner soils where fertility needs building, use material with a lower C:N ratio (ideally 20-25:1), such as green waste compost.
Remember, dark materials absorb heat away from vines, while lighter materials reflect radiation, potentially helping ripening.
Know your soil
Understanding soil properties and characteristics is fundamental to successful management in established and new vineyards.
The TerraMap high definition soil scanning service can measure 21 variables at over 800 data points per hectare, so provides the ideal starting point and can explain site variability.
It maps all common nutrient properties, pH, soil texture, organic matter and Cation Exchange Capacity, plus elevation and available water. Results can be used in Omnia to create accurate, multi-layered management plans.
Winter maintenance tips
Now is an ideal time to finish any remaining tree and boundary maintenance, such as trimming overhanging branches or hedges.
While wind shelter around vineyards is a necessity, shading reduces light interception, slows ripening, and may increase Powdery mildew risk.
Another important task ahead of the growing season is to ensure adequate cold air drainage at the bottom of slopes or hollows by cutting/clearing, purpose-made holes in hedges. On cold nights in spring, cold air sinks downhill and may be trapped in low points creating a frost pocket. Holes allow cold air to escape, reducing the associated frost risk.
Hutchinsons is trialling a microbial soil stimulant at a number of established sites this season to see whether there is any noticeable benefit on vine growth. This will test manufacturer claims that the biologically-active substances produced by the bacteria directly and indirectly benefit the environment, soil fertility and plant growth.