Nov 11, 2011
Portable pressure chambers successful in measuring vine water statusBack
© Reuse this
Dry and windy conditions prior to the 2011 wine grape harvest are proving the merits of wine and spirits pro- ducer Distell’s recent investment in technology to more accurately measure vine water status, reports Distell senior specialist viticulturist Drikus Heyns.
He explains that the measuring technology comprises small portable pressure chambers, or pressure bombs, which gauge the leaf water potential in the vines as a basis for determining optimal irrigation strategies.
The technology was initially developed for research purposes, but it is now used in southern France, Spain and, to a limited extent, elsewhere.
Heyns says although it is important to observe as many variables as possible in the vine’s environment, the most sensitive indicator of stress is the vine itself.
“Until now, we have had to rely mostly on soil water measurements to assess water stress in the vines.“
However, the portable pressure chambers we are using in a range of vineyards across the Cape Winelands enable our viticulturists to measure water stress in the vines and to refine irrigation schedules more accurately than was possible in the past,” he adds.
Further, Heyns explains that vines actually benefit from some water deficit as too much water has a negative effect on grape flavour.
To gauge exactly how much water stress is enough is critical to the health of the vines and to the quality of the grapes they produce.
“When there is too much water stress, the stomatae, or pores of the leaves, close, inhibiting the daytime intake of carbon dioxide, slowing down photosynthesis and limiting growth and the production of the grapes,” he says.
Distell is, at this stage, focusing exclusively on testing the technology at red wine vineyards in the Durbanville, Philadelphia, Paarl and Stellenbosch areas in the Western Cape. Heyns and his team visit the vineyards weekly, testing the same vines each time to assess vine health and water needs.
In each instance, leaves are cut and bagged to limit evapotranspiration. The leaves are also covered with an aluminium sheet, which prevents light from opening the stomatae.
A pressure gauge indicates the level of stress experienced by the vine. The degree of stress indicated by the vine is called stem water potential. The pressure reading enables the user to determine the irrigation required.
Allowing for the rooting depth of the vines, soil texture, soil moisture content and vine canopy size, as well as the type of trellising and row spacing, vine water requirements are determined by the extent of evapotranspiration that occurs in the vine and how far the vine is in the ripening of its grapes.
In addition, each wine grape varietal has its own particular water demands.
“The pressure chambers place us in a far better position to manage the health of the vines and ensure optimal-quality fruit to the cellars,” says Heyns.
Edited by: Chanel de Bruyn© Reuse this Comment Guidelines (150 word limit)
Other Agriculture News
Recent Research Reports
Steel 2015: A review of South Africa's steel sector (PDF Report)
Creamer Media’s Steel 2015 report provides an overview of the key developments in the global steel industry and particularly of South Africa’s steel sector over the past year, including details of production and consumption, as well as the country's primary carbon...
Projects in Progress 2015 - First Edition (PDF Report)
In fact, this edition of Creamer Media’s Projects in Progress 2015 supplement tracks developments taking place under the Renewable Energy Independent Power Producer Procurement Programme, which has had four bidding rounds. It appears to remain a shining light on the...
Electricity 2015: A review of South Africa's electricity sector (PDF Report)
Creamer Media’s Electricity 2015 report provides an overview of State-owned power utility Eskom and independent power producers, as well as electricity planning, transmission, distribution and the theft thereof, besides other issues.
Construction 2015: A review of South Africa’s construction sector (PDF Report)
Creamer Media’s Construction 2015 Report examines South Africa’s construction industry over the past 12 months. The report provides insight into the business environment; the key participants in the sector; local construction demand; geographic diversification;...
Liquid Fuels 2014 - A review of South Africa's Liquid Fuels sector (PDF Report)
Creamer Media’s Liquid Fuels 2014 Report examines these issues, focusing on the business environment, oil and gas exploration, the country’s feedstock supplies, the development of South Africa’s biofuels industry, fuel pricing, competition in the sector, the...
Water 2014: A review of South Africa's water sector (PDF Report)
Creamer Media’s Water 2014 report considers the aforementioned issues, not only in the South African context, but also in the African and global context, and examines the issues of water and sanitation, water quality and the demand for water, among others.
This Week's Magazine
Forest products group Sappi has confirmed the selection of its 25 MW biomass-to-power project, to be erected at its Ngodwana mill, in Mpumalanga, as a preferred bidder under the South African government’s Renewable Energy Independent Power Producer Procurement...
Information and communications technology (ICT) distributor DCC is making Windows- and Android-operating systems tablets available through retailers and education equipment suppliers to provide school children with affordable, high-performance education tools. The...
Another cement manufacturer is set to enter the Ugandan market, raising hopes that prices will come down and spur growth in the construction industry. National Cement, a Kenyan manufacturer, has unveiled plans to invest $195-million in a new manufacturing plant in...
With growth rates exceeding that in the developed world – at an average of between 4% and 5% between 2002 and 2014 – African countries provide investors with ample reason to tap into booming consumer demand says Manufacturing Circle executive director Coenraad...
The South African Chamber of Commerce and Industry’s (Sacci’s) Business Confidence Index (BCI) decreased by 3.7 index points month-on-month to 89.1 in March.