Food security, climate change, and sustainable land management. A review

Agriculture production in developing countries must be increased to meet food demand for a growing population. Earlier literature suggests that sustainable land management could increase food production without degrading soil and water resources. Improved agronomic practices include organic fertilization, minimum soil disturbance, and incorporation of residues, terraces, water harvesting and conservation, and agroforestry. These practices can also deliver co-benefits in the form of reduced greenhouse gas emissions and enhanced carbon storage in soils and biomass. Here, we review 160 studies reporting original field data on the yield effects of sustainable land management practices sequestering soil carbon. The major points are: (1) sustainable land management generally leads to increased yields, although the magnitude and variability of results varies by specific practice and agro-climatic conditions. For instance, yield effects are in some cases negative for improved fallows, terraces, minimum tillage, and live fences. Whereas, positive yield effects are observed consistently for cover crops, organic fertilizer, mulching, and water harvesting. Yields are also generally higher in areas of low and variable rainfall. (2) Isolating the yield effects of individual practices is complicated by the adoption of combinations or "packages" of sustainable land management options. (3) Sustainable land management generally increases soil carbon sequestration. Agroforestry increases aboveground C sequestration and organic fertilization reduces CO2 emissions. (4) Rainfall distribution is a key determinant of the mitigation effects of adopting specific sustainable land management practices. Mitigation effects of adopting sustainable land management are higher in higher rainfall areas, with the exception of water management.