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A little post-harvest care can minimise challenges later

Viticulture
04.03.2021
Vine Talk columnist and Syngenta Technical Services Lead Dr Brandy (Belinda) Rawnsley.
Have you heard the latest tips, tricks and industry advice? Vine Talk author, Dr Brandy (Belinda) Rawnsley takes a look at the issues facing grape growers.

Autumn is a time to breathe a sigh of relief that you’ve made it through the season and your hard work has paid off.  Any down time should be savoured, particularly for viticulturalists, as we turn our attention to post-harvest care. With vineyards heading into leaf fall and dormancy, what we do now sets you up success for next season.

After harvest, the vine hasn’t stopped working. Continued photosynthesis and nutrient uptake during the postharvest period allow vines to store carbohydrate and nutrient reserves. It’s these stored carbohydrates in dormant vines that the vine uses in spring to support new root and shoot growth.

In spring, the vine will rely on stored carbohydrates until the new shoots can undertake sufficient photosynthesis. It’s not until flowering that the canopy can produce its own carbohydrates to replenish wood and root reserves.

Post-harvest, we want to maintain leaf area for as long as possible after harvest with adequate irrigation and nutrition.

Irrigate to bring water to the rootzone back so the vines are ready for winter recharge. Dry soil at budburst will have an influence on uniformity and resulting shoot growth.

Post-harvest nitrogen fertiliser applications can assist with maintaining functional leaf area for a longer period after harvest and replenish lost stored reserves. This period is a key time for N uptake and is critical for use in the next season. Remember, removal of fruit from the vine also removes essential nutrients.

By comparison, phosphorus and potassium are less mobile but application may assist if these were low.  Application of fertilisers in conjunction with irrigation will assist uptake in the vine for storage, otherwise fertilisers may just leach away over the winter.

The amount of time required for vines to restore their carbohydrate and mineral reserves is influenced by crop load.  Low yielding vines need very little time to recover and restore nutrients after being harvested compared to high-yielding crops that require 6-8 weeks of vine care.

Don’t take a break just yet. Look after your vines after harvest and you’ll lay the foundation for success next season.