Secrets of the belowground ecology of tropical perennial grasses help explain carbon drawdown in soils managed without tillage.
In three words – Roots. Microbes. Minerals.
Visible, aboveground greenery is grand and very easy to measure, but the belowground environment (and the organisms that occupy it) is more critical for climate smart and healthy soils. Belowground organisms include roots and microbes that interact with each other and soil minerals via multiple processes to collectively store carbon in high-functioning, climate smart and healthy soils.
Perennial grass species with massive root systems having characteristically low lignin concentration accumulated the most soil carbon during cultivation. Microbial decomposition of dead roots did not result in carbon losses as might be expected, but carbon gains as plant and microbe-derived organic matter quickly transformed from plant debris to mineral-bound organic molecules. Once protected on mineral surfaces, carbon resists further decomposition and accumulates.
Importantly, we tested whether warmer conditions expected with climate change may alter the balance. While the rate of accumulation slowed a bit, carbon accumulated nonetheless – a welcome bit of good news on the climate change mitigation front.