Agricultural sinks in the developing world: Different disciplines and different perspectives

Figures & data

Table I. Carbon sequestration potential of strategies for arable land (Pg C/year).

Practice	Potential
Soil erosion control*	0.08 – 0.12
Soil restoration†	0.02 – 0.03
Conservation tillage and residue management	0.150 – 0.175
Improved farming/cropping systems (intensification)	0.18 – 0.24
Total	0.43 – 0.57

*However, this figure should be compared with Lal's later (2003) estimates of CO₂ lost through erosion. †This estimate includes the use of degraded soils for biofuels production.Source: adapted from Lal and Bruce (1999, p. 182).

Table II. Potential pitfalls of carbon sequestration strategies in agriculture.

	Conservation tillage
Intensification	(including residue management)	Soil erosion control
Increased CO2, N2O and CH4 from manufacture, transport, and use of organic and inorganic fertilizer	Increased incidence of pests and diseases	Confusion as to extent of erosion
	Opportunity costs of retaining crop residues in the field
Equity issues through differing capacities to use inputs	No carbon sequestration without appropriate rotations	Some soils with low organic matter are not worth saving, either for productivity or carbon sequestration
	Changes in soil temperature may affect planting dates
Salinization and groundwater mining through poor irrigation management	Risk, especially with true no-till, of anaerobic soils, reducing net mitigation through N2O emissions	Incentive payments can lead to conservation measures that are not maintained later
Opportunity costs of abandoning monocropping for sustainable rotations		High opportunity cost of scarce labour

Lal , R . 2003 . Soil erosion and the global carbon budget . Environ Int , 29 : 437 – 450 .

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Lal , R and Bruce , J . 1999 . The potential of world cropland soils to sequester C and mitigate the greenhouse effect . Environ Sci Policy , 2 : 177 – 185 .

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