The Crush - October 2021 - 1

Volume 48 Issue 10 October 2021
Post-Harvest Vineyard Management
By Ted Rieger
The end of harvest can be a time to celebrate another season and
the fruits of labor, but it is not the end of work in the vineyard.
For California winegrape growers, it's time to begin post-harvest
vineyard management practices. These may include irrigation
as well as fertilizer and nutrient additions to replenish vine
nutritional levels lost during the growing season for grape and
canopy production. Without sufficient fall rain, post-harvest
irrigation can be even more important, as soils must be moist for
nutrients to move from the soil into the vine roots. A fall season
root growth flush requires adequate soil moisture. Leaves should
also be hydrated, able to transpire and photosynthesize in order to
move nutrients from the root zone into the vine's woody tissues.
The goal of post-harvest irrigation is to maintain a functional
canopy for the vine to store carbohydrates and mineral reserves
for dormancy and be ready for growth the next spring, but
without accumulating excess water and pushing new growth.
Without adequate water and fertilizer to store carbohydrates
and macronutrients in vine tissues, vines may experience later
problems including: winter cold injury, uneven spring bud break,
poor or delayed shoot growth, poor fruit set, and sub-optimal
fruit yield and quality.
Given drought conditions in California, and the uncertainty of
fall/winter rains, water supply and quality could be concerns for
post-harvest irrigation this year. Growers may have to prioritize
use of limited water for vineyards that need it most, or for their
highest value blocks. It may be a good time to remove older,
less productive or diseased vineyards to
maximize water use for more productive
UC Cooperative Extension (UCCE)
viticulture specialist Kaan Kurtural
said, " Some areas may not have enough
Post-harvest drip irrigation maintains soil moisture for vines to uptake nutrients and
store reserves in woody tissues. Photo: Ted Rieger
water supply for a normal post-harvest irrigation. But we still
recommend they irrigate if they can, maybe not at the full rate,
but if possible, maintain canopy size to relieve vine stress,
especially if the vineyard was mechanically harvested. "
Actual water and nutrient needs vary by site, vineyard age,
canopy size and grape yields/crop size. In lighter crop years,
such as 2021, post-harvest water and nutrient application
requirements are lower than normal. For this year, Kurtural
suggests that water applications at 25% of evapotranspiration
(ET) may be adequate to maintain a functional canopy until
Soil salinity may be a concern at some sites, especially with
drought and inadequate rain to flush salts below the root zone.
Fertilizers with lower salt content should be used that do not add
more salinity to soils.
If irrigation water quality/chemistry is a concern, filtration or
chemical additions could mitigate issues prior to applications.
Some vineyards may have access to winery wastewater for
irrigation, but its chemistry/nutrient content should be analyzed.

The Crush - October 2021

Table of Contents for the Digital Edition of The Crush - October 2021

The Crush - October 2021 - 1
The Crush - October 2021 - 2
The Crush - October 2021 - 3
The Crush - October 2021 - 4
The Crush - October 2021 - 5
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The Crush - October 2021 - 10