New study on water needs of pears

Good news for the pear industry – a project to quantify the water requirements of high-performing pear orchards has been approved for funding by the Water Research Commission. By Engela Duvenage.

The project is set to begin in April 2022, and run until 2026. Hortgro will consider co-funding the project from the next financial year, which commences in October 2022.

The project will be led by Dr Sebinasi Dzikiti of the Department of Horticultural Science at Stellenbosch University, in collaboration with the Department of Plant and Soil Sciences at the University of Pretoria, and the Council for Scientific and Industrial Research.

Field trials will run in prime pear-growing areas on Packham’s Triumph and Forelle, the two most-planted cultivars in South Africa. Packham’s Triumph is a green pear while Forelle is a blushed pear. Due to the need to expose Forelle pears to sufficient sunlight for red colour development, the canopies of Forelle trees are kept fairly open. In contrast, Packham’s Triumph trees have denser canopies.

According to Dzikiti, no accurate quantitative information exists on the water requirements of pear orchards. “This paucity of data may cause inaccurate irrigation scheduling and water allocation decisions, leading to inefficient use of often limited water resources.”

There is also little known about the drivers of water use and how this is affected by factors such as canopy cover, cultivar, soils, and microclimates. Some local information is available on how water use by pear trees relates to fruit quality and yields, but these results need to be validated.

The few international studies on the topic unfortunately do not take the water requirements of cultivars grown in South Africa into account.

The overall aim of this study is therefore to close these important information gaps through detailed field experiments aimed at understanding how pear trees interact with their environment in terms of water use and to provide insights on how differences in the management of pear-tree canopies may affect water use and water productivity.