Written by  Ian Goodwin, Lexie McClymont

Water vs pear crop (part 4)

The aim of parking trees is to sacrifice the crop and apply the minimum amount of irrigation so that trees survive and return to full production the following year.

Parking pear trees (cont from last issue)
The aim of parking trees is to sacrifice the crop and apply the minimum amount of irrigation so that trees survive and return to full production the following year.
Trees are managed to minimise the transpiring leaf area and avoid excessive water stress so that developing fruit buds are not desiccated.
The following are recommendations to park trees and minimise irrigation:
•Withhold irrigation until the root-zone (defined as containing 80 per cent of the roots) dries out to a minimum soil water tension of at least 400 kPa.
This occurs at the start of November in the Goulburn Valley after average winter and spring rainfall.
•Use deficit irrigation by applying 30 per cent of orchard water use capability. This is conservative and based on RDI studies conducted at Tatura.
Apply frequent irrigation with less water. In other words, cut irrigation run time back to 30 per cent of full irrigation but maintain irrigation interval similar to full irrigation.
•Remove fruit from the tree.
De-fruiting reduces competition from dry weight accumulation by the fruit and thus increases the amount of carbon available for the developing fruit buds for next season’s crop.
Fruit also consume water for growth and lose water through their skin although the amount is small compared to foliage transpiration.
•Remove water shoots.
Shoot growth will be strong at the start of the season if there is adequate soil moisture from winter and spring rainfall.
(cont next issue)

See this article in Tree Fruit April 2020