Researchers led by the Syria-based International Center for Agricultural Research in the Dry Areas (ICARDA) have developed a low-cost technology to increase crop yield in magnesium-rich soil.
Excessive amounts of magnesium in soil and irrigation water lead to soil degradation as a result of its effects on the soil's physical structure. The magnesium level also affects the amount of other nutrients in the soil, causing a gradual decline in crop yields.
More than 30 per cent of irrigated lands in southern Kazakhstan contain excess magnesium, leading to low cotton productivity.
Researchers at ICARDA and the Kazakh Research Institute of Water Management conducted four-year trials in magnesium-rich soils on farms in the Arya Turkestan area of southern Kazakhstan.
They added phosphogypsum, a waste product of the phosphorus fertilizer industry and a source of calcium — which improves the physical and chemical characteristics of soil — to the fields.
They found that adding an appropriate level of phosphogypsum — determined by simple soil tests — doubled the cotton yield.
A paper detailing the research is due to be published in an upcoming issue of international Land Degradation & Development.
Manzoor Qadir, ICARDA-based marginal water management scientist and head of the initiative to out-scale phosphogypsum technology in central Asia, said in a press release, "[The method] works out very economical for the farmers. It is enough if the farmers apply phosphogypsum once every four to five years."
Magdi Tawfik Abdelhamid, a botanist at Cairo's National Research Centre, told SciDev.Net that the new method "is a cheap, simple, reliable and promising tool for increasing cotton yield in high-level magnesium soil in other cotton-producing developing countries such as Egypt, Sudan and Syria".
He also called for programmes and field experiments to be launched in irrigated areas in Africa and Latin America to evaluate the effects of phosphogypsum application in those regions.
Researchers have indicated the need to assess any risks associated with phosphogypsum transportation and application by farmers, as some grades of phosphogypsum can contain relatively high levels of radioisotopes.