eChapter Name: Organic Agriculture and Climate Change
9789390083664
eBook Name: PRINCIPLES OF ORGANIC FARMING (WITH THEORY AND PRACTICALS)
by E. Somasundaram, D. Udhaya Nandhini, M. Meyyappan
Climate change mitigation is urgent, and adaptation to climate change is crucial, particularly in agriculture, where food security is at stake. The gases contributing to the greenhouse effect mainly include carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4). These gases have varying global warming potentials, which can be expressed in CO2 equivalents.
Agriculture, currently responsible for 2030% of global greenhouse gas emissions (counting direct and indirect agricultural emissions), can however contribute to both climate change mitigation and adaptation. The main mitigation potential lies in the capacity of agricultural soils to sequester CO2 through building organic matter. This potential can be realized by employing sustainable agricultural practices, such as those commonly found within organic farming systems. Examples of these practices are the use of organic fertilizers and crop rotations including legume leys and cover crops. Mitigation is also achieved in organic agriculture through the avoidance of open biomass burning, and the avoidance of synthetic fertilizers, the production of which causes emissions from fossil fuel use.
Organic agriculture is associated with higher carbon sequestration as many organic practices help to improve soilquality and carbon sequestration. The most common organic practices that increase soil organic carbon are the use of organic fertilizers (such as the composted waste products from livestock husbandry), crop rotation involving legumes and the planting of cover crops.
Organic farming offers several ways to mitigate climate change when compared to conventional agriculture:
Primarily, organic farming, through its key practices of organic fertiliser use and crop rotations with forage legumes, tends to increase soil organic carbon levels resulting in carbon sequestration.This contributes to climate change mitigation, as it absorbs CO2 from the atmosphere and stores the additional carbon in the soil. However, depending on soil type and climatic conditions, this process usually comes to a halt after some decades, when soil organic carbon levels have reached a new equilibrium and soils arethus saturated with respect to organic carboncontents. Furthermore, this storage of organiccarbon is reversible and the carbon can again be released into the atmosphere as carbon dioxide when switching to unsustainable practices.