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26 March 2018 Photo Pixabay
Back to the drawing board to save water
We’ve managed to damage nature’s ‘filter’ with air, ocean, and soil pollution, and by destroying wetlands.

Dr Cindé Greyling, a University of the Free State (UFS) DiMTEC (Disaster Management Training and Education Centre for Africa) alumni, studied drought mitigation with a strong focus on communicating important water-saving information. 

Can we run out of water?
Yes, and no, says Dr Greyling. “To our knowledge, water is not ‘leaking’ through our atmosphere. We have what we have, but that doesn’t mean we will have enough clean, fresh water forever. Nature has a magnificent way of purifying water through the water cycle. We, on the other hand, must use a lot of money and energy to purify water. Also, we’ve managed to damage nature’s ‘filter’ with air, ocean, and soil pollution, and by destroying wetlands. The other problem is a simple supply and demand scenario. More people will need more water, but not only that, population growth calls for industry development and increased food supplies – all of which require more water.”    

A war over water
Besides some Hollywood impressions, it is difficult to imagine a war over water, but it is possible. “Some experts are convinced that we are heading there, and others claim that such tensions already exist. Personally, I don’t favour these kinds of shock tactics (or truths) – social research has shown us that it rarely leads to behavioural changes. We can learn a lot from what was has been done in Cape Town. Although we all think people were bombarded with ‘Day-Zero’-scares, they were actually encouraged to adapt their behaviour with a communication campaign that hardly ever used the term ‘Day-Zero’. This approach mobilised citizens to reach record lows of water usage.” 

Adapt a new normal
Dr Greyling encourages the “new normal” set in motion by Capetonians. “Water consciousness is needed, even when the rain comes again. We’ve taken water for granted for too long. As consumers, we have the power to turn this situation around – drop for drop. Be aware about the amount of water you use, how you use it, and for what. Keep in mind that any wastage and pollution (of ‘dry’ things) also wastes and pollutes water. Generally, we need to behave better regarding consumption.”  

News Archive

Well-established root system important for sustainable production in semi-arid grasslands
2015-02-24

Plot layout where production and root studies were done
Photo: Supplied

The importance of a well-established root system for sustainable production in the semi-arid grasslands cannot be over-emphasised.

A study of Prof Hennie Snyman from the Department of Animal and Wildlife and Grassland Sciences at the University of the Free State is of the few studies in which soil-water instead of rainfall has been used to estimate above- and below-ground production of semi-arid grasslands. “In the past, plant ecological studies have concentrated largely on above-ground parts of the grassland ecosystem with less emphasis on root growth. This study is, therefore, one of the few done on root dynamics in drier areas,” said Prof Snyman.

The longevity of grass seeds in the soil seed bank is another aspect that is being investigated at present. This information could provide guidelines in grassland restoration.

“Understanding changes in the hydrological characteristics of grassland ecosystems with degradation is essential when making grassland management decisions in arid and semi-arid areas to ensure sustainable animal production. The impact of grassland degradation on productivity, root production, root/shoot ratios, and water-use efficiency has been quantified for the semi-arid grasslands over the last 35 years. Because of the great impact of sustainable management guidelines on land users, this study will be continuing for many years,” said Prof Snyman.

Water-use efficiency (WUE) is defined as the quantity of above- and/or below-ground plant produced over a given period of time per unit of water evapotranspired. Sampling is done from grassland artificially maintained in three different grassland conditions: good, moderate, and poor.

As much as 86, 89 and 94% of the roots for grasslands in good, moderate and poor conditions respectively occur at a depth of less than 300 mm. Root mass is strongly seasonal with the most active growth taking place during March and April. Root mass appears to be greater than above-ground production for these semi-arid areas, with an increase in roots in relation to above-ground production with grassland degradation. The mean monthly root/shoot ratios for grasslands in good, moderate, and poor conditions are 1.16, 1.11, and 1.37 respectively. Grassland degradation lowered above- and below-ground plant production significantly as well as water-use efficiency. The mean WUE (root production included) was 4.79, 3.54 and 2.47 kg ha -1 mm -1 for grasslands in good, moderate, and poor conditions respectively.

These water-use efficiency observations are among the few that also include root production in their calculations.

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