The key to cutting the global food gap in half is water

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To feed the global population, we are going to need to produce anywhere from 60 to 100 percent more crop calories by 2050—and we need to do it without ruining the planet along the way. Much discussion has gone into how to close this so-called food gap, yet very little of it has focused on improving water management, says researcher Jonas Jägermeyr of the Potsdam Institute for Climate Impact Research in Germany. That’s remarkable considering that agriculture is the number one consumer of freshwater on the planet.

Jägermeyr says that part of the reason why water management is a neglected solution is that the extent to which it can increase crop yields has not been studied on a broad scale—until now, that is. A modeling study he recently co-authored for the journal Environmental Research Letters presented the first-ever global calculation of this kind, finding that integrated water management measures could feasibly cut the global food gap by half, without converting any more land into farms or drawing any more water from natural bodies of water.

“There is huge potential associated just with a better use of agricultural water,” he says.

The researchers used biophysical computer simulations to calculate how a variety of water management techniques—including some decidedly low-tech interventions—affect agricultural production under the current climate and a variety of future climate change scenarios. These included measures to retain soil moisture, such as leaving previous harvests’ crop residues on the ground or covering the soil with mulch or plastic. For rain-fed agriculture, water management measures included both collecting water that runs off crop lands for use during dry spells and implementing measures, such as terracing and contouring farm lands, to reduce runoff before it happens. They also considered improving irrigation systems.

The researchers estimated three possible scenarios depending on degrees of implementation of these techniques. The middle scenario—which Jägermeyr says is ambitious yet feasible—shows that a combination of these techniques can increase crop calorie production by 41 percent. Gains would be even greater in areas where a lack of water is the major limitation to increased yields. Improved water management takes on special importance in the face of climate change, which is expected to increase droughts and the variability of rainfall patterns.

For Jägermeyr, now that the numbers are in—and are so impressive—it is time for water management to become a bigger part of the conversation on how to feed the planet. —Catherine Elton | 4 March 2016

Source: Jägermeyr, J. et al, 2016. Integrated crop water management might sustainably halve the global food gap. Environmental Research Letters (11). doi:10.1088/1748-9326/11/2/025002

Header image: Texas A&M AgriLife Research photo by Kay Ledbetter