University of Illinois: Soybeans With Fewer Leaves Yield More

Researchers at the University of Illinois have discovered soybeans produce more leaves than needed, which is detrimental to yield. The group says this problem will only get worse with rising atmospheric carbon dioxide.

To test this theory, researchers removed about one third of emerging leaves on soybeans to discover an 8% seed yield increase. The group attributes this increase to better photosynthesis, decreased respiration and diversion of resources that would have been invested in leaves rather than seeds.

“Reduction in the leaves allows more sun light to penetrate through the canopy making the whole plant more productive, and it also reduces crop water demand,” says Praveen Kumar, project lead and Lovell professor of civil and environmental engineering at the University of Illinois.

Their research indicates that a 30% to 40% decrease in leaf area will increase yield by up to 10% and even cutting just 5% of leaf area would still increase yields by 8%.