Soil Carbon: a Critical Natural Resource – Wide-scale Goals, Urgent Actions - Soil Carbon: Science, Management and Policy for Multiple Benefits - page 13

Food-secure regions, predominant in
developed countries, are often characterized
by excess nutrient inputs in their farming
systems, which can affect other ecosystem
services negatively through pollution and
greenhouse gas emissions (Csathó et al .,
2007; Vitousek et al ., 2009). Optimizing and
sustaining current and future food produc-
tion by maintaining the functionality of soils
and minimizing the negative impact on
other ecosystem services must be the major
aim of a bold new programme of technical
research and agricultural land management.

and wind erosion (Blanco-Canqui and Lal,
2007). The decrease in runoff and increase
in infiltration contribute to recharging aqui-
fers, and to preventing water pollution by
decreasing the transport of nutrients and
other contaminants to fresh waters. Soil or-
ganic carbon also improves water quality by
acting as a filter of herbicide and pesticide
residues and other pollutants that contam-
inate water reservoirs and streams (Lertpai-
toonpan et al ., 2009; Rodriguez-Liébana
et al ., 2013).
At the catchment scale, practices that
increase SOC are required to improve water
recharge (quantity) and purification (qual-
ity). In the short term, regulations at national
or subnational levels, mainly in developing
countries, must stimulate water erosion
control measures in order to reduce the pol-
lution of stream water and the effects of
disasters such as hurricanes on the down-
stream population and infrastructure and to
ensure the availability of potable water for
human consumption (Bradshaw et al ., 2007;
Brandimarte et al ., 2009). Adequate prac-
tices for increasing SOC at the catchment
scale must be adopted by the farmers of the
catchment area. Farmers could be grouped
in farmer organizations, advised by experts
from local, national and international insti-
tutions, including private organizations, and
legally regulated and stimulated by the gov-
ernment. Practices to increase SOC that can
be implemented immediately to reduce run-
off and increase water infiltration include
no till, cover crops, agroforestry, afforest-
ation and others, complemented by specific
technologies like terraces, contours and
strip cropping (Mishra et al ., 2010; Powlson
et al ., 2012). The cumulative effects of these
and newer practices are hot topics for re-
search. Land tenure policies that favour
increases in SOC are needed to accompany
these practices, particularly at the catch-
ment level.
Once regulations are implemented,
there is a need to monitor changes in SOC, in
order to quantify its effects on the improve-
ment of water quality and quantity. This
should include the monitoring of the water
table, hydrological regime and sediment
loads in stream water. The results of this

Water

Land use affects the quality and quantity of
water strongly in many watersheds (Swal-
low et al ., 2009). One of the most important
water pollution problems related to land
use are the excess nutrients applied for agri-
cultural production but which flow into
surface and coastal waters (Ahrens et al .,
2008). Nitrate and phosphate contamin-
ation are well-known examples, but also
pesticides enter both groundwater and sur-
face-water bodies. Nutrients in surface waters
can cause eutrophication, hypoxia, algal
blooms and other infestations (such as of
water hyacinth), which have been observed
in coastal areas and many inland water bod-
ies on all continents (Swallow et al ., 2009;
Mateo-Sagasta and Burke, 2010). Water pol-
lution has increased with the increased use
of mineral fertilizers and higher concentra-
tions of livestock (FAO, 2011). In light of
these facts, the goal is to ensure the provi-
sion of sufficient quantity and quality of
water needed for multiple uses by increas-
ing SOC.
Soil organic carbon and protective vege-
tative cover are critical to maintaining the
quality and quantity of water available for
human consumption and plant production
in the long term, because SOC determines
soil properties that regulate in multiple ways
the hydrological pathways within the soil.
Soil organic carbon increases soil aggre-
gates, which improves water infiltration and
decreases the susceptibility of soil to water