Characterization of the Global Sources of Atmospheric Ammonia from Agricultural Soils

Abstract

Global ammonia (NH 3 ) emissions to the atmosphere are projected to increase in the coming years with the increased use of synthetic nitrogen fertilizers and cultivation of nitrogen-fixing crops. A statistical model (NH 3 _STAT) is developed for characterizing atmospheric NH 3 emissions from agricultural soils and compared to the performance of other global and regional NH 3 models (e.g., Emission Database for Global Atmospheric Research, Magnitude and Seasonality of Agricultural Emissions, MIX, and U.S. Environmental Protection Agency). The statistical model was developed from a multiple linear regression between NH 3 emission and the physicochemical variables. The model was evaluated for 2012 NH 3 emissions. The results indicate that, in comparison to other data sets, the model provides a lower global NH 3 estimate by 58%, (NH 3 _STAT: 13.9 Tg N yr −1 ; Emission Database for Global Atmospheric Research: 33.0 Tg N yr −1 ). We also performed a region-based analysis (United States, India, and China) using the NH 3 _STAT model. For the United States, our model produces an estimate that is a~1.4 times higher in comparison to the Environmental Protection Agency. Meanwhile, the NH 3 _STAT estimate for India shows NH 3 emissions between 0.8 and 1.4 times lower when compared to other data sets. A lower estimate is also seen for China, where the model estimates NH 3 emissions 0.4 to 5 times lower than other data sets. The difference in the global estimates is attributed to the lower estimates in major agricultural countries like China and India. The statistical model captures the spatial distribution of global NH 3 emissions by utilizing a simplified approach compared to other readily available data sets. Moreover, the NH 3 _STAT model provides an opportunity to predict future NH 3 emissions in a changing world. − ), and nitrous oxide (N 2 O); and organic nitrogen such as urea, amino acids, and proteins. Many of these are biologically active, chemically reactive, and radiatively active in the Earth's atmosphere and biosphere, in contrast to nonreactive nitrogen gas (N 2 ).

Effect of Chitosan Inclusion and Dietary Crude Protein Level on Nutrient Intake and Digestibility, Ruminal Fermentation, and N Excretion in Beef Heifers Offered a Grass Silage Based Diet

“…During the period 2002–2016, significant increases in NH 3 emissions were observed over several of the world’s major agricultural regions [ 3 ]. Approximately 80% of global NH 3 emissions are a result of anthropogenic sources (animal and crop agriculture) [ 4 ]. In Ireland, agriculture is responsible for 99.1% of NH 3 emissions, with the application of animal manures accounting for 90% of the total figure [ 5 ].…”

Meta-Analysis of Strategies to Reduce NH3 Emissions from Slurries in European Agriculture and Consequences for Greenhouse Gas Emissions

“…Ammonia (NH 3 ) and its salts are major contributors to eutrophication, and corresponding abatement strategies might lead to increased greenhouse gas (GHG) emissions [2]. Agriculture, mainly livestock production, is the greatest contributor to the emission of ammonia (NH 3 ) [2][3][4]. The GHGs from animal husbandry are nitrous oxide and methane.…”

“…The latter is mainly produced by enteric fermentation and manure storage, and has an effect on global warming 28 times higher than carbon dioxide [5]. The general demand for measures to abate emissions of NH 3 due to the 2 of 14 rise in livestock production has led to the development of various manure management strategies, at different stages of the manure management chain (animal diets and housing, manure treatment, storage, and application) [3,6]. Livestock production is projected to double in the next century to accommodate the growing world population [7], which is expected to reach 9 billion by 2050 [8].…”

“…The sensitivity of agricultural practices to NH 3 and GHG emissions has paved the way for new policies, leading to changing trends and technologies compared to the old practices. New policies are still emerging [3,16]. For example, the new Danish regulation on pig production mandates pig farm owners to implement NH 3 abatement strategies, such as acidification and air-scrubbing techniques [17].…”

A thermophilic chemolithoautotrophic bacterial consortium suggests a mutual relationship between bacteria in extreme oligotrophic environments

“…The long history of repetitive grass burning of vegetal material may have facilitated selection of thermophilic carboxydotrophic bacteria that comprise the unique metabolisms observed in our CNF consortium. Several sources, including biomass burning, are responsible for the emission of CO, CO 2 , H 2 , NOx, N 2 O, and NH 3 27 , which may have enhanced the microorganisms that are able to grow without any source of organic carbon and nitrogen by consuming gaseous atmosphere (CO, N 2 , and O 2 ). The persistence of the less-abundant taxa observed over the continuum replication process (>3 years) indicated that the organisms are either complementing each other’s metabolism or are benefiting from the secondary metabolites from different players.…”