Agricultural Management Impact on Greenhouse Gas Emissions

Abstract

Management practices used on croplands to enhance crop yields and quality can contribute about 10-20% of global greenhouse gases (GHGs: carbon dioxide [CO 2 ], nitrous oxide [N 2 O], and methane [CH 4 ]). Some of these practices are tillage, cropping systems, N fertilization, organic fertilizer application, cover cropping, fallowing, liming, etc. The impact of these practices on GHGs in radiative forcing in the earth's atmosphere is quantitatively estimated by calculating net global warming potential (GWP) which accounts for all sources and sinks of CO 2 equivalents from farm operations, chemical inputs, soil carbon sequestration, and N 2 O and CH 4 emissions. Net GWP for a crop production system is expressed as kg CO 2 eq. ha −1 year. −1 Net GWP can also be expressed in terms of crop yield (kg CO 2 eq. kg −1 grain or biomass yield) which is referred to as net greenhouse gas intensity (GHGI) or yieldscaled GWP and is calculated by dividing net GWP by crop yield. This article discusses the literature review of the effects of various management practices on GWP and GHGI from croplands as well as different methods used to calculate net GWP and GHGI. The paper also discusses novel management techniques to mitigate net CO 2 emissions from croplands to the atmosphere. This information will be used to address the state of global carbon cycle.Keywords: crop yield, greenhouse gas, global warming, potential, management practice, soil carbon sequestration OverviewManagement practices on croplands can contribute about 10-20% of global greenhouse gases (GHGs: carbon dioxide [CO 2 ], nitrous oxide [N 2 O], and methane [CH 4 ]) [1,2]. Quantitative estimate of the impact of these GHGs in radiative forcing in the earth's atmosphere is done by calculating net global warming potential (GWP) which accounts for all sources and sinks of CO 2 equivalents from farm operations, chemical inputs, soil carbon (C) sequestration, and N 2 O and © 2018 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.CH 4 emissions [3,4]. Net GWP for a crop production system is expressed as kg CO 2 eq. ha −1 year. −1Net GWP can also be expressed in terms of crop yield (kg CO 2 eq. kg −1 grain or biomass yield)which is referred to as net greenhouse gas intensity (GHGI) or yield-scaled GWP and is calculated by dividing net GWP by crop yield [3]. These values can be affected both by net GHG emissions and crop yields. Sources of GHGs in agroecosystems include N 2 O and CH 4 emissions (or CH 4 uptake) as well as CO 2 emissions associated with farm machinery used for tillage, planting, harvesting, and manufacture, transportation, and applications of chemical inputs, such as fertilizers, herbicides, and pesticides, while soil carbon sequestration rate can be either a sink or source of CO 2 [4][5][6]. In the calculations o...

A Review of Greenhouse Gas Emissions from Agricultural Soil

“…Manure management controls CH4 and N2O emissions through techniques like composting and optimizing the application timing [133]. Sustainable agricultural management techniques are essential for reducing the GWP, enhancing soil carbon sequestration, and lowering the GHG emissions [134]. These practices promote a sustainable and climate-resilient agriculture while improving soil health and productivity and can reduce the GWP.…”