https://phys.org/news/2018-07-carbon-ground-halting-farmland-expansion.html

"We found that the first strategy—what we call 'land sparing'—resulted in a greater amount of carbon being stored than any other. So, slightly counter-intuitively, trying to conserve carbon on farmland resulted in less carbon being stored across the landscape as a whole. This was because it resulted in lower yields and so required larger areas to produce the same amount of food, and therefore meant less land could be spared for natural habitats."

To investigate the impacts of different land-use strategies, the researchers needed to have study sites across the whole range of possible land-uses, from zero-yield natural habitats through low-yield farming and then through to high-yield sites. Those sites also needed to be comparable: having the same soils, climate, slope, and more. They also needed reliable ways to measure yields—how much food each site produced per unit area—and the carbon stored on each site.