Soil carbon sequestration in the agro-landscapes: the food imperative of the climate agenda

Indicative data from Russian and international literature sources on the extent of carbon sequestration by terrestrial ecosystems, mainly soils, at the global and regional levels are presented. It was noted, however, that these estimates were too approximate, highly debatable and require reliable experimental verification. It was suggested that close to real amounts of soil carbon sequestration in Russia and in the World will be obtained only in the future, with using data from long-term monitoring studies based on modern approaches and methods, including long-term field experiments. The terms of “soil carbon sequestration” were considered and a critical analysis of these definitions was given. Significant differences between the terms “soil carbon sequestration” and “soil carbon accrual” were noted, as well as the need to introduce into scientific discourse the term of “soil carbon depositing”, emphasizing the long-term preservation of carbon in the soil. It was pointed out that a complete quantitative assessment of soil carbon sequestration should include both the amount of organic matter input into soil and the gain in soil Corg, as well as the time during which carbon is retained in the soil. A list of the main reasons and factors limiting the process of carbon sequestration in soils was presented. The literature data on soil carbon accrual under different carbon sequestration agrobiotechnologies were summarized. It was concluded that the soils in the managed ecosystems, occupying significant areas in most countries of the world, have a significant potential for sequestration of atmospheric carbon and its transfer into soil organic matter. However, the technologies and approaches adopted for carbon sequestration does not guarantee a sustainable increase in Corg in the soil. Thus, the goal of climate- smart agriculture should be a reasonable compromise between climate and food aspects of the carbon problem by solving the triune aim of maintaining and/or improving soil fertility, increasing crop yields and mitigating anthropogenic carbon dioxide emissions.