Soil Management
A number of key issues must be considered in relation to soil management, such as soil structure, moisture holding capacity, and nutrient availability. There is also a need to consider such things as how to maintain good soil porosity, the bacterial activity in the soil that leads to fertility, and the effects of pH. The water holding capacity of a soil is important in dry-grown vineyards and is improved by increased organic matter and mulching. Thirty-six percent of Henschke vineyards are dry grown and the soil management techniques now used lead to the production of very high quality fruit. Many different techniques of soil management exist. Henschke has moved completely away from mechanical disturbance and now uses permanent sward. Mulching with wheat straw to avoid herbicide treatment under the vine is used in most of the vineyards, and allows more organic matter to be incorporated into the soil and preserves soil moisture. Earthworms also open up the soil and introduce nutrients and soil ameliorants such as lime. Mulching helps to maintain the fertility of the soil without the addition of nitrogen fertilisers, which often favour the development of disease, especially botrytis. A good balance of nutrients in the top 60 to 70 centimetres of soil is important for the production of premium grapes. The vineyards are currently run incorporating organic and biodynamic practices, including biodynamic compost being produced from all the winery by-products, such as grape marc, stalks and waste water, cow pit peat and 500 and 501 preparations.