Urea deep placement: Increasing yields, decreasing fertilizer waste

by John Collins Rudolf

A new agricultural technology that cuts nitrogen fertilizer waste in half while increasing rice yields is spreading quickly in Bangladesh and is being investigated by 15 other nations, including more than a dozen in sub-Saharan Africa.

Chemical fertilizers are critical to raising crop yields, but their cost has been prohibitive for many subsistence farmers, particularly those in Africa.

The inefficiency of fertilizer application is also a major problem. By some estimates, as much as 70 percent of nitrogen fertilizer applied to crops in developing nations is lost to runoff or released into the atmosphere, contributing to coastal “dead zones,” global warming, ozone layer depletion and other problems.

The new technology is fairly simple. Rather than applying urea, a nitrogen fertilizer, to the soil surface in tiny granules, the urea is compacted into briquettes and placed several inches below ground.

These briquettes release nitrogen slowly, dramatically reducing the amount of fertilizer washed away by rain or absorbed by the air. The technique has raised rice yields while limiting the amount of the nitrogen available to weeds, curbing herbicide use.

“The farmers are using nearly 40 percent less urea, and yet they are producing nearly 20 percent more rice,” said Amit Roy, the president of the International Fertilizer Development Center, a nonprofit research group that helped develop the technology, known as “urea deep placement.”

New York Times