Articles
Sap flow dynamics of young and mature pomegranate (Punica granatum L.) orchards under semi-arid conditions
Article number
1419_3
Pages
19 – 26
Language
English
Abstract
Accurate quantitative information on the transpiration rates of pomegranate orchards is essential for irrigation scheduling, especially in semi-arid countries like South Africa.
Water resources in major fruit-producing catchments in South Africa are almost entirely allocated, and water scarcity is exacerbated by climate change and climate variability.
Currently, there needs to be more accurate quantitative information on the water requirements of pomegranate orchards in South Africa.
This study seeks to close this critical information gap using data from young and mature pomegranate orchards under drip irrigation.
The study was conducted on commercial farms in the Porterville and Drakenstein districts in the Western Cape Province of South Africa.
Transpiration was measured using the Heat Ratio Method (HRM) method.
Weather data was recorded using an automatic weather station.
Sap flow measurements were conducted for seven months (October to April) during the 2022/2023 growing season for eight trees that varied in stem diameter, and out of the eight trees, one tree from the young orchard and two trees from the mature orchard was selected for this study.
The young pomegranate tree’s average daily sap flow rate (stem diameter 45 mm) ranged from 1.10 to 4.97 L tree‑1 day‑1. The mature trees (stem diameter 72 and 90 mm) showed higher sap flow rates ranging from 1.10 to 14.17 L tree‑1 day‑1. The highest transpiration rates were observed in January during the middle of the summer season.
The major drivers of the transpiration rates for pomegranate trees were radiation and vapor pressure deficit.
Water resources in major fruit-producing catchments in South Africa are almost entirely allocated, and water scarcity is exacerbated by climate change and climate variability.
Currently, there needs to be more accurate quantitative information on the water requirements of pomegranate orchards in South Africa.
This study seeks to close this critical information gap using data from young and mature pomegranate orchards under drip irrigation.
The study was conducted on commercial farms in the Porterville and Drakenstein districts in the Western Cape Province of South Africa.
Transpiration was measured using the Heat Ratio Method (HRM) method.
Weather data was recorded using an automatic weather station.
Sap flow measurements were conducted for seven months (October to April) during the 2022/2023 growing season for eight trees that varied in stem diameter, and out of the eight trees, one tree from the young orchard and two trees from the mature orchard was selected for this study.
The young pomegranate tree’s average daily sap flow rate (stem diameter 45 mm) ranged from 1.10 to 4.97 L tree‑1 day‑1. The mature trees (stem diameter 72 and 90 mm) showed higher sap flow rates ranging from 1.10 to 14.17 L tree‑1 day‑1. The highest transpiration rates were observed in January during the middle of the summer season.
The major drivers of the transpiration rates for pomegranate trees were radiation and vapor pressure deficit.
Publication
Authors
M. Ravuluma, P.C. Tharaga, T. Volschenk, S. Dzikiti, S. Walker
Keywords
transpiration, stems, sap flow, radiation, reference evapotranspiration
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