The climatic context before and after budbreak plays a very important role in shaping the vintage effect. Temperature accumulation and soil moisture availability initialize the plant cycle with carry over consequences that can last until harvest.
Abundance or scarcity of water in the ground will affect root activity. From the pure perspective of vineyard water use, soil evaporation after rain as well as cover crop transpiration will contribute to decrease the amount of water initially available for vine roots uptake.
During and after budbreak:
In California, the 2013 challenge….
… so far is to assess whether the large amount of winter rains received in November and December still affect the vine at budbreak. In theory, such a large amount of winter rain provides enough water for vine root reservoir to refill up to its maximal capacity before the season starts.
However, in practice, due to root reservoir size limitations, soil evaporation and cover crop transpiration during the dryer months of January through April, we could expect early vine shoot growth reduction in response to early soil moisture deficit. During that sensitive phase, careful monitoring of shoot elongation is particularly effective for the first weeks of “explosive” leaf development. Such information is key to reveal whether early shoot growth restriction is observed in response to the most recent and dryer months.
To be continued…
Thibaut and Sebastien