Water vs pear crop

Horticulture production in a changing climate faces the prospect of continued severe water shortages at regular intervals.

During the Millennium drought, options for minimising irrigation applications to pear orchards were investigated by Agriculture Victoria.
Parking trees and post-harvest irrigation cut-off were evaluated in terms of potential water savings and the impacts on current and future production and are discussed here.
Regulated deficit irrigation (RDI) has been established as an effective technique to control vigour and maintain yield, with the added benefit of lower water use, and is also discussed.
Regulated deficit irrigation
RDI is a well-known strategy that saves water and reduces excessive vegetative growth with no effect on fruit size.
Less irrigation than optimum crop water requirement is applied during the period when shoot growth is rapid and fruit growth is slow.
Given the reduction in vegetative growth from RDI, it is likely that radiation levels reaching the lower parts of the canopy will increase, which will improve colour of blush pear cultivars, soluble solids concentration and firmness of the fruit.
There are distinct growth stages in fruit trees (see Figure 1) and the success of RDI depends on varying the application of irrigation during each of these stages.
Fruit cell division
In most seasons in the Goulburn Valley, pears are not irrigated until reference crop evapotranspiration (ETo) exceeds rainfall by 125 mm.
This allows the soil to dry out so that water stress can develop during the slow fruit growth period.
However, in recent years there has been insufficient winter and early spring rain to wet up the root zone. Root zone soil moisture must be measured to avoid water stress.
Moisture should be accounted for over the entire root zone i.e. to a depth of 600 to 800 mm.
Soil should not be allowed to dry out beyond 60 kPa in clay loam soils.
Slow fruit growth (cont next month)

See this article in Tree Fruit Jan 2020

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