University of Bonn researchers found that soil degradation is significantly reducing crop yields worldwide. Reversing human-caused degradation could increase production enough to feed approximately 70 million more people.
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Researchers estimate that a 10% increase in soil degradation reduces crop yields by an average of 2%, while reversing degradation could substantially expand the global food supply.
Soil erosion, dehydration and compaction are significantly reducing crop yields worldwide, according to research led by the University of Bonn.
The study found that every 10% increase in land degradation is associated with an average 2% decline in crop yields. Reversing human-caused degradation by 10% globally could increase production enough to feed approximately 70 million more people, based on the researchers’ calculations.
The findings were published in Nature Food.
Measuring the Global Crop Yield Gap
Researchers divided the world’s arable land into 10-by-10-kilometre sections and compared areas with similar temperatures and precipitation levels. They adjusted the results for differences in fertilizer use, irrigation and other production factors.
“Now, for the first time, we’ve attempted to quantify the consequences of degradation for all the arable land around the world,” explains Dr. Hadi Hadi, a postdoctoral researcher in the Land Economics Group at the University of Bonn, who carried out many of the analyses for the recently published study.
The team used highly productive areas with little soil damage as benchmarks for estimating how much comparable farmland could produce without degradation, according to a press release.
“Thus, these areas give us a benchmark for what’s possible in soils that haven’t been degraded or influenced in any way,” explains Professor David Wuepper, head of the Land Economics Group.
Five Forms of Soil Degradation Assessed
The researchers examined five degradation factors: erosion, dehydration, soil compaction caused by heavy agricultural machinery, soil carbon loss and limited vegetation cover.
Machine-learning methods were then used to determine how these factors contributed to the crop yield gap in each area.
“Taking an average of all the parcels gives us an approximate rule of thumb,” Hadi says: “A 10 percent increase in the degradation rate cuts the yield by an average of 2 percent. Conversely, if we could reduce degradation by 10 percent all over the world, crop yields would grow by such an extent that we’d be able to feed over 70 million more people.”
The researchers said soil degradation can be slowed or reversed through measures including agricultural regulations and agri-environmental payments.
“Overall, the findings show how important soil quality is to the supply of agricultural produce,” says Wuepper, who is also a member of the PhenoRob Cluster of Excellence and the Sustainable Futures Transdisciplinary Research Area.
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