It is well known that plants compete for sunlight with other plants. But researchers have also discovered that a similar competition is going on underground: plants compete with each other at the root level.
In a new study, Princeton researchers used pepper plants grown in a greenhouse to test different models for predicting root growth. They found that plants invest differently in root structures depending on whether they are planted together or alone. Plants that are close together invest heavily in their root systems to compete for finite underground resources, such as water and various nutrients. When alone, however, they invest much less in their root structures because the pressure to compete is lessened.
The study also provides invaluable insight into understanding how plants store carbon and, importantly, how this might help mitigate climate change. “While the above-ground parts of plants have been extensively studied, including how much carbon they can store, we know much less about how below-ground parts — that is, roots — store carbon,” said Ciro Cabal, a Princeton graduate student. “As about a third of the world’s vegetation biomass, hence carbon, is below ground, our model provides a valuable tool to predict root proliferation in global earth-system models.”