Developing guidelines for the partial root drying irrigation approach from a soil texture perspective.
Howell, C L
Howell, C L
Myburgh, P A
Water is becoming an increasingly scarce resource and must therefore be used optimally. Partial rootzone drying (PRD), as an irrigation technique to save water, is becoming increasingly popular in Australia and other grape producing areas. There are no guidelines for plant available water depletion levels on various soil textures. The aim of this project is to determine allowable depletion levels for different soil textures. Due to international criticism against the use of potted grapevines for partial rootzone drying studies based on recent research results, it is recommended that the project should rather be a field trial instead of a split root pot experiment. For this purpose, a vineyard in the Breede River Valley with two different soil textures, e.g. clay loam and coarse sand will be used. To obtain the PRD effect, irrigation will be applied to one half of the root system at a time. Each soil texture will be irrigated at three plant available water (PAW) depletion levels, namely 50% PAW depletion, 70% PAW depletion and 90% PAW depletion. Each soil texture will also have a treatment that is irrigated conventionally by means of a single dripper line on the vine row.