Articles
Are pecan orchards the best use of irrigation water in semi-arid regions of the Northern Cape province of South Africa?
Article number
1409_15
Pages
103 – 110
Language
English
Abstract
In water-stressed regions, irrigators are facing increasing pressure to use water more efficiently.
But how do irrigators know if they are using water efficiently and if the crop they are producing is the ‘best’ use of that water? In the Northern Cape province of South Africa pecan production has steadily increased over the last 20 years and there is concern that pecan orchards use more water than the traditional annual crops grown in this region.
Fair comparisons need to be made if any policy decisions are to be based on water use indicators, and if industry benchmarking exercises are to inform real improvements in water management by growers.
Estimations of crop water productivity (WPc) and economic water productivity (EWPc), using both evapotranspiration (ETc) and applied irrigation water for two pecan orchards in different regions, indicated that these values vary quite considerably between seasons and regions.
When compared to other annual and perennial crops, WPc for pecans did not compare favourably, due largely to the lower yield of oil-rich pecan nuts.
However, when comparing EWPc, pecans tended to have a higher Rand value per unit of water consumed and irrigation applied.
This suggests that pecan production in this semi-arid region of South Africa is justified, but efforts still need to be made to use water more efficiently in these orchards.
Exercises to determine the most productive use of water in a catchment should not focus on only one or two metrics, and should also take socio-economic and ecological factors into account.
But how do irrigators know if they are using water efficiently and if the crop they are producing is the ‘best’ use of that water? In the Northern Cape province of South Africa pecan production has steadily increased over the last 20 years and there is concern that pecan orchards use more water than the traditional annual crops grown in this region.
Fair comparisons need to be made if any policy decisions are to be based on water use indicators, and if industry benchmarking exercises are to inform real improvements in water management by growers.
Estimations of crop water productivity (WPc) and economic water productivity (EWPc), using both evapotranspiration (ETc) and applied irrigation water for two pecan orchards in different regions, indicated that these values vary quite considerably between seasons and regions.
When compared to other annual and perennial crops, WPc for pecans did not compare favourably, due largely to the lower yield of oil-rich pecan nuts.
However, when comparing EWPc, pecans tended to have a higher Rand value per unit of water consumed and irrigation applied.
This suggests that pecan production in this semi-arid region of South Africa is justified, but efforts still need to be made to use water more efficiently in these orchards.
Exercises to determine the most productive use of water in a catchment should not focus on only one or two metrics, and should also take socio-economic and ecological factors into account.
Authors
N.J. Taylor, J.G. Annandale, N. Shongwe, R. Godfrey, C.S. Everson, M. van der Laan, E. Roux, J.C. Jordaan
Keywords
crop water productivity, economic water productivity, evapotranspiration, yield
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