Water warning for agriculture

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 09 June 2011

Climate change will have major impacts on the availability of water for growing food and on crop productivity in the decades to come, warns a new FAO [Food and Agriculture Organization of the United Nations] report.

Loss of glaciers will eventually impact the amount of surface water available for agriculture

‘Climate Change, Water, and Food Security’ is a comprehensive survey of existing scientific knowledge on the anticipated consequences of climate change for water use in agriculture.

These include reductions in river runoff and aquifer recharges in the Mediterranean and the semi-arid areas of the Americas, Australia and southern Africa — regions that are already water-stressed. In Asia, large areas of irrigated land that rely on snowmelt and mountain glaciers for water will also be affected, while heavily populated river deltas are at risk from a combination of reduced water flows, increased salinity, and rising sea levels.

Additional impacts described in the report:

An acceleration of the world’s hydrological cycle is anticipated as rising temperatures increase the rate of evaporation from land and sea. Rainfall will increase in the tropics and higher latitudes, but decrease in already dry semi-arid to mid-arid latitudes and in the interior of large continents. A greater frequency in droughts and floods will need to be planned for but already, water scarce areas of the world are expected to become drier and hotter.

Even though estimates of groundwater recharge under climate change cannot be made with any certainty, the increasing frequency of drought can be expected to encourage further development of available groundwater to buffer the production risk for farmers. Continue reading

Trees used to detect polluted groundwater

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 30 April 2011

Researchers at Missouri University of Science and Technology have developed a method to detect the presence of soil and groundwater contamination without turning a shovel or touching the water. Instead, they’re using trees.

Missouri S&T researchers use a device called a solid-phase microextraction fiber, or SPME, to detect traces of chemicals at minute levels in trees.

The process, called “phytoforensics,” takes less time and costs much less than traditional detection methods, says Dr. Joel Burken, professor of civil and environmental engineering at Missouri S&T. In recent years, Burken and his colleagues have tested their method at more than 30 sites in five countries and eight states, including five communities in Missouri.

The process involves coring trunks of trees to gather small samples. In past tests, Burken and his students collected those samples in vials to take back to a laboratory at Missouri S&T for analysis. More recently, however, they’ve been using a specially designed, less intrusive approach that uses a thin filament called a solid-phase microextraction fiber, or SPME, to detect traces of chemicals at minute levels, down to part per trillion or parts per quadrillion.

“The process of core-sampling plants has been around for a while,” Burken says, “but we’re taking a new approach that will improve the process on multiple levels. Sampling is easy, fast and inexpensive for quickly identifying polluted areas or contamination patterns.”

Trees act as nature’s solar-driven sump pumps, soaking up water from the ground by using the energy of the sun and the air around them, Burken says. Through a process known as “evaportranspiration,” a tree’s extensive root system absorbs all the water it needs. At the same time, the tree absorbs trace amounts of chemicals in that water and transports it above the ground. Continue reading