In the warmer irrigated grape growing regions of Australia vines may retain a functional canopy for up to three months after harvest. The length of the period varies between varieties and harvest date of the crop. Leaf damage caused by machine harvesting may reduce the effectiveness of canopy, and therefore the amount of carbohydrate and nutrient reserves accumulated in the permanent structure. The importance of post-harvest carbohydrate reserve accumulation for vine productivity was investigated in two hot-climate Semillon vineyards. These vineyards were located in a major Australian grape growing region (Riverina, NSW), but differed in productivity level. Six treatments were imposed at harvest to alter vine reserve accumulation (or length of the post harvest period) over two growing seasons. A reduction in vine reserves by removing leaves after harvest lead to lower yields, particularly after the second year the treatments were implemented. The increase of vine reserves by removing crop at mid ripening for two consecutive seasons lead to elevated yields. Leaf damage and juice spray treatments designed to reduce canopy effectiveness after harvest had only a minor impact on reserves and vine productivity. Both vineyards responded similarly to the treatments, but the relationship between starch wood levels (cordon and trunk) and yields was more pronounced in the more productive vineyard. These changes in productivity levels emphasised the importance of vine reserves for various stages of reproductive development. The post-harvest period could provide an opportunity for deliberate management of reserve accumulation to influence next years yield and reduce seasonal variability. This could be achieved by vineyard irrigation and nutrition management in this remaining part of the growing season.
|Number of pages||13|
|Journal||Office International de la Vigne et du Vin. Bulletin: revue internationale|
|Publication status||Published - 2007|