Researchers at the University of California, Berkeley have shown that well-established agricultural management practices such as planting cover crops, optimizing grazing and sowing legumes on rangelands, could capture enough carbon from the atmosphere and store it in the soil to make a significant contribution to international global warming targets.
The study found that improved agricultural management could reduce global temperatures 0.26°C. If biochar, obtained by burning crop residue in an oxygen-free environment, is also added, these practices could reduce warming by as much as 0.46°C.
The effect mostly comes from the improvement of degraded agricultural and grazing lands that are in use but producing less than optimally. Improved management tends to increase the biomass of crops, grass and their root systems by capturing carbon dioxide via photosynthesis, which results in more carbon storage in the soil.
Increasing the organic content of soils increases the fertility, water-holding capacity, sustainability, decreasing erosion and general resilience to climate change as well as sequestering carbon.
The researchers did not consider additional practices, such as composting, or the effect of improving soil on abandoned land, both of which could increase soil carbon sequestration even more.
On the other hand, soil improvement has a reduced beneficial effect once there is a higher concentration of carbon in the atmosphere.