From Potential to Implementation: An Innovation Framework to Realize the Benefits of Soil Carbon - Soil Carbon: Science, Management and Policy for Multiple Benefits - page 50

1

Subsistence
farming, no or
low off-farm input,
soil degradation

Invention

New
equilibrium

Adoption of
RMPs

100

5

Innovative
technology

Maximum
potential

80

4

Rate

Attainable
potential

∆ Y

60

3

2

∆ X

40

Accelerated erosion

20

0

Time (years)

Fig. 4.1. The soil organic carbon transition curve: (1) naturally stable level; (2) reduced unstable level
under conventional land use; (3) application of standard widely known and tested sequestration tech-
niques; (4) application of existing innovative sequestration techniques; (5) application of hitherto unknown
sequestration techniques. (From Lal, 2008.)

(Johnson, 1995). Alternatively, in a worst-case
scenario where C input remains smaller than
C output , the system may ultimately collapse
as described by Lal (2008b) and others
(Chapter 3, this volume). On adoption of re-
commended management practices (RMPs)
( Fig. 4.1 , arrow 3), whereby C input > C output ,
SOC levels may again increase until a new
stable level is reached (C input ~ C output ). This
'attainable potential' can be achieved with
widely known and tested sequestration
techniques ( Table 4.1 ). Similar consider-
ations apply when innovative sequestration
techniques (Fig. 4.1 , arrow 4) have to be im-
plemented to reach the next level of restor-
ation, termed maximum potential in Fig. 4.1.
A rise in carbon content above the natural
reference ( Fig. 4.1 , arrow 5) may require new
unprecedented conditions.
The benefits of increasing SOC content
in the soil are wide-ranging and well known
(see Smith et al ., 2008; Victoria et al ., 2012;
Bationo et al ., 2014; Chapters 10 and 14,
this volume). Suitable management prac-
tices to build up SOC are those that increase
the input of organic matter to the soil and/or

decrease the rate of SOM decomposition
(e.g. Johnson, 1995; Paustian et al ., 1998;
FAO, 2011). The most appropriate practices
are site specific, being adapted to soil type
and land-use system (e.g. Batjes, 1998; In-
gram and Fernandes, 2001). The magnitude
and rate of SOC sequestration that may be
achieved depends on several factors, in-
cluding the reference SOC stock (for a given
land unit), land-use history, soil type (depth
of soil, clay content and mineralogy, in-
ternal drainage/aeration, soil nutrient status)
and soil and water conservation practices.
The total (project) area where intervention
will take place should be divided into
homogeneous units (e.g. climate, soils and
land use) termed 'strata'. Defining these
units, i.e. stratification, allows researchers
to obtain precise estimations at a lower
cost than treating the entire region as a
homogeneous unit (see McKenzie et al .,
2002; IPCC, 2006; Ravindranath and Ostwald,
2008).
Technological land management options
for enhancing soil carbon sequestration gen-
erally include a judicious combination of: