Nov 11, 2011
Portable pressure chambers successful in measuring vine water statusBack
Durbanville|Paarl|Philadelphia|Stellenbosch|Environment|Resources|Water|France|Spain|Too Much Water Stress|Water Stress|Cape Winelands|Water|Measuring Technology
© 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
Updated 7 hours ago Increased maintenance costs, poor rolling mill yields and strike action have widened Evraz Highveld Steel’s operating loss, from R149-million in the nine months ended September 30, 2013, to R483-million for the comparative 2014 period. The company added on Monday...
Updated 7 hours ago Energy Minister Tina Joemat-Pettersson has misled Parliament and should be suspended pending an investigation, the DA said on Monday. "Reports indicate that the minister was involved in recommending and appointing Mr Tshepo Kgadima as chairman of the board of...
Recent Research Reports
Defence 2014: A review of South Africa's defence industry (PDF Report)
Creamer Media’s Defence 2014 report examines South Africa’s defence industry, with particular focus on the key participants in the sector, the innovations that have come out of the sector, local and export demand, South Africa’s controversial multibillion-rand...
Road and Rail 2014: A review of South Africa's road and rail infrastructure (PDF report)
Creamer Media’s Road and Rail 2014 report examines South Africa’s road and rail transport system, with particular focus on the size and state of the country’s road and rail network, the funding and maintenance of these respective networks, and the push to move road...
Real Economy Year Book 2014 (PDF Report)
This edition drills down into the performance and outlook for a variety of sectors, including automotive, construction, electricity, transport, steel, water, coal, gold, iron-ore and platinum.
Real Economy Insight: Automotive 2014 (PDF Report)
This four-page brief covers key developments in the automotive industry over the past 12 months, including an overview of South Africa’s automotive market, trade figures, production and the policies influencing the sector.
Real Economy Insight: Construction 2014 (PDF Report)
This five-page brief covers key developments in the construction industry over the past 12 months. It provides an overview of the sector and includes details of employment in the sector, infrastructure and municipal spending, as well as insight into companies’...
Real Economy Insight: Electricity 2014 (PDF Report)
This five-page brief covers key developments in the electricity industry over the past 12 months, including details of State-owned power utility Eskom’s generation activities, funding and tariffs, independent power producers and prospects for the sector.
This Week's Magazine
JSE-listed real estate investment trust (REIT) Rebosis Property Fund achieved a distribution growth of 8.1% to 99.45c per linked unit in the financial year ended August 31, despite volatile market conditions.
A low-cost, inflatable incubator won this year’s international James Dyson design award, which aims to encourage and inspire the next generation of design engineers.
The World Bank released its ‘Doing Business 2015: Going Beyond Efficiency’ report last month and ranked South Africa 43 out of 189 global economies for its ease of doing business, with Singapore topping the rankings.
Air Products South Africa officially launched its R300-million Eastern Cape air- separation unit (ASU), at its new manufacturing facility in the Coega Industrial Development Zone (IDZ), earlier this month. It is the second facility that Air Products launched in South...
BMW South Africa (SA) has signed a power purchasing agreement with energy company Bio2Watt. The offtake partnership will bring renewable energy to the carmaker’s Rosslyn plant, north of Pretoria.