http://www.engineeringnews.co.za
  SEARCH
Login
R/€ = 13.57Change: -0.05
R/$ = 12.17Change: 0.15
Au 1171.95 $/ozChange: -6.60
Pt 1078.00 $/ozChange: -0.50
 
 
Note: Search is limited to the most recent 250 articles. Set date range to access earlier articles.
Where? With... When?








Start
 
End
 
 
And must exclude these words...
Close Main Search
Close Main Login
My Profile News Alerts Newsletters Logout Close Main Profile
 
Agriculture   Automotive   Chemicals   Competition Policy   Construction   Defence   Economy   Electricity   Energy   Environment   ICT   Metals   Mining   Science and Technology   Services   Trade   Transport & Logistics   Water  
What's On Press Office Tenders Suppliers Directory Research Jobs Announcements Letters Contact Us
 
 
 
RSS Feed
Article   Comments   Other News   Research   Magazine  
 
 
Nov 11, 2011

Portable pressure chambers successful in measuring vine water status

Back
Aluminium|Environment|Health|Resources|Testing|Water|Water
Aluminium|Environment|Health|Resources|Testing|Water|Water
aluminium|environment|health|resources|testing|water-company|water
© 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.
Distell is piloting the technology not only to further enhance grape quality but, also to employ scarce water resources more strategically.

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.
The petiole of the vine leaf, which is the stalk attaching the leaf to its stem, is cut and the leaf is quickly placed in the chamber with the cut end of the petiole protruding from the chamber. As the pressure in the chamber equals the pressure or tension in the leaf, the sap is forced out of the cut petiole surface.

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
Creamer Media Senior Deputy Editor Online
© Reuse this Comment Guidelines (150 word limit)
 
 
 
 
 
 
 
 
Other Agriculture News
Ashok Thakur
India’s largest utility vehicle and tractor producer, Mahindra & Mahindra, has established a new business unit specifically focussed on emerging opportunities in Africa. The African business unit will be headed by current Mahindra South Africa (MSA) CEO Ashok Thakur,...
Tanzania, home to Mt. Kilimanjaro and the Serengeti National Park, has a tradition of protecting land for the sake of ecological diversity and beauty. Now the country has a new reason to add to its protected sites list: electricity.
More
 
 
Latest News
Updated 39 minutes ago Gauteng Premier David Makhura recommitted the provincial government’s support to the revival of Gauteng’s manufacturing base, telling the second yearly Manufacturing Indaba on Tuesday that policymakers would drive legislation that created an environment in which the...
Updated 4 hours ago The Competition Commission has reached a settlement agreement with Japanese shipping liner Nippon Yusen Kabushiki Kaisha (NYK) for contravening the Competition Act in the transportation of motor vehicles to and from South Africa by sea. This settlement followed the...
Updated 4 hours ago State-owned aerospace and defence technology conglomerate Denel on Tuesday launched a book to demystify defence technology to South African learners and attract them to the defence industry’s career opportunities, while creating greater awareness about innovation and...
More
 
 
Recent Research Reports
Real Economy Year Book 2015 (PDF Report)
There are very few beacons of hope on South Africa’s economic horizon. Economic growth is weak, unemployment is rising, electricity supply is insufficient to meet demand and/or spur growth, with poor prospects for many of the commodities mined and exported. However,...
Real Economy Insight: Automotive 2015 (PDF Report)
Creamer Media’s Real Economy Year Book comprises separate reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, gold, iron-ore and platinum sectors.
Real Economy Insight: Water 2015 (PDF Report)
Creamer Media’s Real Economy Year Book has been divided into individual reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, coal, gold, iron-ore and platinum sectors.
Real Economy Insight: Construction 2015 (PDF Report)
Creamer Media’s Real Economy Year Book has been divided into individual reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, coal, gold, iron-ore and platinum sectors.
Real Economy Insight: Electricity 2015 (PDF Report)
Creamer Media’s Real Economy Year Book has been divided into individual reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, coal, gold, iron-ore and platinum sectors.
Real Economy Insight: Road and Rail 2015 (PDF Report)
Creamer Media’s Real Economy Year Book has been divided into individual reports under the banner Real Economy Insight and investigates key developments in the automotive, construction, electricity, road and rail, steel, water, coal, gold, iron-ore and platinum sectors.
 
 
 
 
 
This Week's Magazine
JSE-listed Afrimat will make a cash offer to acquire the entire remaining issued share capital of subsidiary Infrasors that it does not already own.
TEAMWORK Aggreko Europe, Middle East & Africa MD David Taylor-Smith; Aggreko Zambia chairperson Dr. Sixtus Mulenga; Aggreko Africa MD James Shepherd
Temporary power generation services provider Aggreko announced earlier this month that it had appointed Dr Sixtus Mulenga as nonexecutive chairperson of Aggreko Zambia, a move it believed was integral to the ongoing expansion of its operations in Zambia and the rest...
Major global aircraft manufacturer Airbus Commercial Aircraft is maintaining a steady course. "I don't have any big news, good or bad," company President and CEO Fabrice Brégier told international aviation journalists in Toulouse, France, at the company’s recent...
MEASURING DEVICES Bosch has released a mobile app that enables the measurements made with measuring devices to be sent and used directly on the app for accuracy and on-site quoting
Industrial tool manufacturer Bosch has increased the compatibility of many batteries in its range of blue industrial power tools and has released mobile-device applications (apps) for users of the tools, says Bosch South Africa training manager Peter du Bruyn. Many...
The new Nissan Navara has been launched onto the global market, but Nissan South Africa (NSA) will only know in August whether the local Rosslyn plant will assemble the one-ton pickup. The NSA plant currently produces the old NP300 Hardbody one-ton bakkie, as well as...
 
 
 
 
 
 
 
 
 
Alert Close
Embed Code Close
content
Research Reports Close
Research Reports are a product of the
Research Channel Africa. Reports can be bought individually or you can gain full access to all reports as part of a Research Channel Africa subscription.
Find Out More Buy Report
 
 
Close
Engineering News
Completely Re-Engineered
Experience it now. Click here
*website to launch in a few weeks
Subscribe Now for $96 Close
Subscribe Now for $96