Current estimates of soil C storage potential are based on models or factors that assume linearity between C input levels and C stocks at steady-state, implying that SOC stocks could increase without limit as C input levels increase. However, some soils show little or no increase in steady-state SOC stock with increasing C input levels suggesting that SOC can become saturated with respect to C input.

1. why do the authors conclude that, Soil in highly
structured and high organic matter soils can
display a finite capacity to store carbon.

2. Content..
• Objectives
• Introduction
• Carbon sequestration
• The importance of carbon for the plant growth.
• Background of the experiment.
• Methodology.
• The effect of different farming practices on crop production
& soil fertility.
• RESULTS.
• Discussion.
• Conclusion.

3. • To identify why do the
authors conclude that,
Objective.
‘Soil in highly structured and
high organic matter soils can
display a finite capacity to store
carbon.”
Objective.

4. • Carbon is a chemical element.
• Saturated carbon is a ‘carbon atom in an organic
species that is bonded to other atoms only by
single bonds’.
Introduction.

5. • Soil Organic Carbon (SOC) is one part in the
much larger global carbon cycle that involves the
cycling of carbon through the soil.
• Soil organic carbon sequestration is the process
by which carbon is fixed from the atmosphere.
Introduction.
SOM (Soil organic matter)

6.  The process of capturing and storing atmospheric
carbon.
 One of method that reduce the CO2 concentration in
the atmosphere.
Carbon sequestration

7.  Soil organic carbon is the basis of soil fertility. It
releases nutrients for plant growth.
 Organic carbon is helps to improve soil structure and
holding moisture capacity.
 Many management practices that increase soil organic
carbon also improve crop and pasture yields.
 Higher level of organic carbon reduce
bulk density.
The importance of carbon for the
plant growth

8. why do the authors conclude
that,
Soil in highly structured and
high organic matter soils can
display a finite capacity to
store carbon.

9. • Experiment located :- Ellerslie, AB (Alberta), Canada
• Objective :- Testing C saturation by physical and chemical
protection of SOM in soils that are already rich in organic
matter.
• Used :- 4 replicated combinations of 3 treatments.
I. 2 types of straw management (straw retained and straw
removed)
II. 2 tillage systems (no-till and conventional tillage)
III. 3 rates of fertilizer application (0, 50, and 100 kg N
ha−1 yr−1)
Background of the experiment

10. Methodology
1. Soil aggregate was fractioned as,
2. Soil carbon & nitrogen were analyzed and determined
cumulative soil carbon input.
 Used method -: stable isotope analyzer
2. Determined the relationship between C input and SOC
concentration.
 Large macroaggregates (>2000 μm),
 Small macroaggregates (2000–250 μm)
 Microaggregates (250–53 μm)
 Silt plus clay fraction (<53 μm)
Native grassland soil
Experimental plots

11. • Soil organic matter (SOM) increase the soil fertility and supply
energy for soil.
• Extra organic carbon and accumulated only in the particulate
organic matter (POM) fraction under greater soil C inputs.
• The main effects of farming practices are :
 straw retention
 Tillage
 N fertilization
The farming practices are changed, according to :
 Weight proportion (Table 1 )
 SOC concentration ( Table 2 )
 Soil N concentration (Table3)
The effect of different farming practices on
crop production & soil fertility.

12. Combinations of treatments applied in this
Experiment. There were four field replicates
for each treatment

13. Table 1 : weight proportion of straw
retention, tillage & N fertilization of soil.
• The straw and tillage treatments had a significant interactive effect
on the weight proportion of the silt plus clay (SC) fraction isolated
from the whole soil.

14. Table 2 : SOC concentration of straw
retention, tillage & N fertilization of soil
• The SOC concentration in the whole soil or the
fractions isolated soil not change the straw, tillage,
or N fertilization treatments .

15. Table 3 : Soil N concentration of straw
retention, tillage & N fertilization of soil.
• The soil N concentration increased to a small degree under the straw
retention and N fertilization treatments in a few soil fractions.
• There are no important interactions between the straw and tillage
treatments or between the tillage and N fertilization treatments on
the soil N concentration of the whole soil or any soil aggregates.

16.  Conclude that C sequestration is governed by C
saturation in this highly structured and high-C
soil.
 Suggest, soils of temperate ecosystems have a
finite capacity to store C and that soil carbon
saturate may be more evident in soil that are
high in organic matter content.
Conclusion

17. Therefore
authors conclude that,
Soil in highly structured and high
organic matter soils can display a
finite capacity to store carbon.