x Abu Dhabi, UAE Thursday 20 July 2017

Soil samples indicate land degradation

Urgent action is needed to stop Abu Dhabi's land becoming irreversibly degraded, according to a government-backed report.

Urgent action is needed to stop Abu Dhabi's land becoming irreversibly degraded, according to a government-backed report. A team working for the Environment Agency - Abu Dhabi (EAD) found that about 90 per cent of the farms around Al Ain have salinity problems. Irrigation is causing salt to build up in the soil, with no means of removing it, the report found. This, in turn, causes the soil to break down and become desert.

The study, based on 50,000 soil samples from around the emirate, found that off-road vehicles and overgrazing were also damaging the surface layer, compacting it and leaving it prone to being blown away. Mahmoud Ali Abdelfattah,the Egyptian soil scientist commissioned by the EAD to help compile the assessment, said human activities "ultimately lead to very poor wildlife habitat and ecosystem destruction".

These man-made problems combined with natural ones, including drought, wind erosion and sand encroachment, to put Abu Dhabi's land under significant threat of erosion. The report, published in the most recent edition of the Soil Science Society of America Journal, did note the success of forest planting projects in slowing erosion. But Dr Abdulfattah warned that "land degradation is a matter of urgency and must be accorded greater significance on the environmental agenda".

"An emirate-wide action plan needs to be developed and implemented to manage and combat all types of degradation," he added. He said that stable farmland was being put at risk by irrigation with saline water. With little rainfall, salt added to the soil by irrigation is not leached out, causing it to build up over time and eventually rendering the land unusable. If the water in the soil is too saline, plants are unable to absorb it and cannot grow. Without the plants' root structure to bind the soil together, the surface layer breaks down into smaller particles that can be carried by the wind.

"Soil salinity is becoming a threat to agricultural farms and coastal areas," said Dr Abdelfattah. "Irrigation leads to phenomenal enhancement of land productivity. "However, if this important resource is mismanaged, it can cause soil degradation and increase salinisation risk." The study found that on 68 per cent of farms, the water in the groundwater wells was very strongly saline - more than 8,000 parts per million.

The soil was classed as saline in almost nine in 10 farms in the Al Ain area, with seven in 10 being saline enough to restrict crop yields, or force farmers to cultivate salt-tolerant crops. Only 11 per cent of farms in the area were classified as non-saline or normal. The emirate's response needed to include identifying and planting salt-tolerant species, making more efficient use of irrigation water, and developing proper drainage for farmland, to allow the salt to leach out of the soil.

Farmland also be protected by planting forests or even lines of trees to create wind breaks and stop sand dunes shifting. The report noted the previous success of the emirate's forest-planting project, introduced by Sheikh Zayed, the founder of the UAE, in preventing land degradation and stabilising the soil. "Afforestation has been practiced on about 330,000 ha in Abu Dhabi emirate. In addition, many green belts in urban areas and along roadsides have been established," Dr Abdulfattah said.

"The implementation of afforestation was considered a preventive measure for some of the desert lands that are not yet degraded or are only slightly degraded. Although vegetation was the best way of making the soil clump together to resist erosion, it could also be improved with organic matter, such as manure or mulch, or synthetic polymers. The report noted that many farms also had serious problems with waterlogging.

It also noted that "overgrazing in general has reduced the biodiversity in many areas" and that "landfilling for urban development and construction purposes" was also causing land to be degraded. Dr Abdelfattah said the report on Abu Dhabi was in the context of a worldwide loss of nearly two billion hectares of biologically productive land through irreversible degradation.

That total was increasing by about 10ha of arable land each minute, half to soil erosion and more than a quarter to salinity. jhenzell@thenational.ae