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Lal. Carbon Footprints 2026, 5, 10 Page 15 of 20

pastureland is also scanty , and there is a lack of information linking SOC sequestration to agronomic
[92]
productivity on organic-managed cropland and grazing land using models .
[93]
The cost of SOC sequestration is also not adequately researched. For example, Uludere et al. estimated the
[94]
technical potential of 19.4 Tg CO eq per year for the U.S. cropland, of which 10 Tg CO eq could be
2
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sequestered at the cost of U.S. $100/Mg CO eq. Credible estimates of the cost of SOC sequestration are
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needed to implement carbon farming and pay farmers for sequestration of soil C.

Research data are also needed on the soil microbiome and its effects on SOC sequestration. Beattie et al. [95]
indicated that critical gaps with regard to microbiome include understanding of the processes influencing the
transformation of plant-derived soil C into humus or SOM content and identification of the microbes and
microbial activities impacting this transformation, along with potential ecological ramifications and
uncertainties. Based on these and other information, research challenges for C sequestration in global soils
include socioeconomic and biophysical aspects, as briefly described in Table 3.

CONCLUSIONS
Research information on soil C sequestration has been improved and strengthened since circa 2000. It is a
popular topic and the one that has strong effects on a range of issues including agronomic, climatological,
food and nutritional security, carbon farming, and policy. Whereas notable progress has been made during
the first quarter of the 21st Century, a lot needs to be done because of emerging issues that need to be
addressed. Despite its potential for C sequestration of as much as 2.5 Pg to 3 Pg C/year, this biophysical and
natural process of land-based solution to climate change by itself cannot offset the fossil fuel emissions
estimated at 10 Pg C/year in the 2020s. However, with identification and implementation of renewable
energy sources (bio, hydro, wind, geothermal, solar and nuclear), sequestration of C in land-based sinks can
lead to C neutrality by 2050 and beyond. Realization of the C sequestration potential of land-based sinks
necessitates the development of policies that are pro-nature, pro-agriculture, and pro-farmers. Rewarding
farmers for payments of ESs, at a societal value of US $50 per credit (1 metric ton of CO eq), requires the
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establishment of the Soil Health Act at the local, national, and international levels, which has provisions for
incentivizing land managers. There is also a need for education of students (from primary school to college),
the general public, and policy makers to enhance awareness of the role of soil health in general and that of C
sequestration in particular, so that C farming can be upscaled globally. In addition to adaptation and
mitigation of climate change, soil C sequestration has numerous co-benefits: food and nutritional security,
water quality and renewability, strengthening biodiversity, and restoring degraded soils and ecosystems.
Land managers (i.e., farmers, ranchers, foresters, urban developers), the biggest stewards of soil resources,
must be respected and rewarded financially for their role in transforming agriculture from being a problem
to an integral part of the solution to restoring the environment and advancing the SDGs of Agenda 2030 of
the United Nations.

DECLARATIONS

Authors' contribution
The author contributed solely to the article.

Availability of data and materials
Not applicable.

Financial support and sponsorship
None.

Conflicts of interest
The author declared that there are no conflicts of interest.