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Carbon sequestration
Global warming is under way and could increase in the future, with a concomitant negative impact worldwide. CO2 is a major greenhouse gas. In application of the Kyoto Protocol, a strategy is required which combines low energy consumption, the use of lowcarbon energy sources, and carbon sequestration. Agriculture-oriented countries could actively participate in reducing greenhouse gas emissions by implementing alternative cropping practices like DMCs that have a high carbon sequestration potential.
GREENHOUSE GAS EMISSION AND AGRICULTURAL ACTIVITIES Featured
The increase in the atmospheric concentration of greenhouse gases (CO2, CH4, N2O, H2O) is contributing to global warming—this mainly involves carbon dioxide (CO2). The volume of CO2 released into the atmosphere accounts for 50% of the greenhouse effect. However, nitrogen oxides (NO and N2O) also have a substantial impact because, at equal volume, the effect of N2O is 200- to 300-fold greater than that of CO2! The extent of greenhouse gas emissions from agricultural activities and their potential reduction by agricultural practices are now documented. Agriculture is involved in the greenhouse effect at two levels, i.e. as a greenhouse gas emitter and as a carbon sink. Agricultural activities actually account for over 23% of total CO2 emissions. Fuel combustion, livestock production effluents and nitrogen fertilizer applications in agriculture also increase nitrogen oxide release. Many agricultural activities thus have an impact on carbon sequestration or greenhouse gas emission: tillage, input management ...
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SOILS AND VEGETATION: MAJOR CARBON SINKS Featured
Carbon sequestration involves capturing carbon emitted by different sources (e.g. vehicles) and storing it in a sink (soil, vegetation, ocean, etc.). Plants represent the startpoint of the carbon cycle. Through photosynthesis, plants absorb atmospheric carbon (CO2) and store it in their biomass (leaves, wood, roots, flowers and fruits). This organic matter nourishes heterotrophic organisms (consumers). Carbon (CO2) is released into the atmosphere through the respiration of heterotrophic and autotrophic organisms. The carbon balance should be mentioned when discussing carbon ‘sinks’. Vegetation and soil are considered as carbon sinks when they fi x (or accumulate) more carbon than they release. Storing carbon in the soil is therefore both an agricultural (improvement in the physicochemical soil properties) and environmental (reduction in the quantity of atmospheric CO2) challenge. Soils represent an enormous carbon sink. Globally, soils sequester more carbon (1,550 billion tonnes) than the atmosphere ( ...
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BENEFICIAL IMPACTS OF DMCS ON CARBON SEQUESTRATION Featured
Large-scale DMC implementation could substantially help to control air pollution, in general, and especially global warming. DMCs have several impacts on the CO2 balance, i.e. by reducing emissions and especially carbon sequestration:DMCs eliminate tillage which is a major contributor to CO2 release. In tropical agriculture, tillage accelerates organic matter decomposition (microbial mineralization) and thus carbon release. Under DMCs, agriculture becomes a net CO2 storer and is no longer a net producer. • DMCs decrease or even halt soil erosion, and thus the loss of carbon-fixing organic matter.DMCs markedly increase soil organic matter levels within a few years, therefore enabling carbon fixation in crop residue and cover plant derived organic matter accumulated in the soil. The quantity of carbon that can be sequestered is thus mainly dependent on the extent of increase in plant biomass and its nature (the higher the ligninin content in the annually recycled harvest residue, the greater its involveme ...
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