Abstract
Drought is a major risk in global agriculture. Building-up soil organic carbon (SOC) enhances soil fertility and efficient use of rainwater, which can increase drought tolerance in food production. SOC management demonstrates its benefit at various locations and is a promising means to achieve food security and climate mitigation at once. However, no global assessment of its potential and co-benefits gained from SOC enhancement has been presented. Here we evaluated the extent to which SOC build-up could reduce agricultural drought risk. Using statistical analysis of spatially-explicit global crop and soil datasets, we find that relatively small enhancement in topsoil (0–30 cm) organic carbon content (OCtop) could increase drought tolerance of the food production systems operating over 70% of the global harvested area (particularly drylands). By closing the gap between current and upper limit of tolerance levels through SOC addition of 4.87 GtC at the global scale, farmer’s economic output in drought years would increase by ~16%. This level of SOC increase has co-benefit of reducing global decadal mean temperature warming by 0.011 °C. Our findings highlight that progress towards multiple development goals can be leveraged by SOC enhancement in carbon (C)-poor soils in drier regions around the world.
Highlights
Drought is a major risk in global agriculture
Building up soil organic carbon (SOC) helps to maintain soil moisture at levels that enable crops to withstand water deficit[7,8,9,10] because (i) soil organic matter (SOM) in which SOC acts as a backbone has enormous water holding capacity and (ii) SOM enhances the formation and stability of porous soil structure which ensures the adequate balance of moisture and aeration for plants and soil biota[2]
We examined two benefits of the SOC enhancement: (i) agricultural economic output in drought year, which has implications for small farmer’s income and access to food, and (ii) climate mitigation
Summary
Building-up soil organic carbon (SOC) enhances soil fertility and efficient use of rainwater, which can increase drought tolerance in food production. By closing the gap between current and upper limit of tolerance levels through SOC addition of 4.87 GtC at the global scale, farmer’s economic output in drought years would increase by ~16%. This level of SOC increase has co-benefit of reducing global decadal mean temperature warming by 0.011 °C. We examined two benefits of the SOC enhancement: (i) agricultural economic output in drought year, which has implications for small farmer’s income and access to food, and (ii) climate mitigation. We assessed four major crops (maize, rice, wheat and soybean), which together accounts for two thirds of the world’s food calories
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