Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 16
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Book Description
In Canada, agriculture's share of anthropogenic nitrous oxide (N2O) emissions is estimated to be about 59%. Accurate estimates of annual N2O emissions at field, regional, and national scales are required to establish baseline values of emissions of this potent greenhouse gas, to compare current N2O management strategies & identify best management practices, and to evaluate & monitor the impact of management changes. This paper discusses the difficulties in measuring N2O emissions from agricultural sources, then describes N2O estimation methods found in the literature. It includes information on the IPCC methodology, the DNDC (DeNitrification DeComposition) model by Li et al. (1992), the CENTURY model of Parton et al. (1993), the Expert-N system of Baldioli et al. (1974), and research on validation of models for Canadian conditions. Finally, directions for further research are suggested.
Author: Maria Ponce De Leon Jara
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Crop rotations, organic nutrient amendments, reduced tillage practices, and integration of cover crops are practices that have the potential to increase the sustainability of crop production, yet they also impact nitrous oxide (N2O) emissions. Agricultural soil management has been estimated to contribute 79% of the total N2O emissions in the U.S., and inorganic nitrogen (N) fertilization is one of the main contributors. Nitrous oxide is a potent greenhouse gas that has a global warming potential which is approximately 298 times that of carbon dioxide (CO2) over a 100-year period and is currently the dominant ozone-depleting substance. Few studies have assessed the effects of organic N amendments on direct N2O within the context of a typical dairy forage cropping system. Most research has been limited to studying the effects of one or two sources of N inputs on N2O emissions; however, dairy forage cropping systems often apply manure and have more than two N sources that likely both contribute to N2O emissions. This study investigated how different dairy cropping practices that include differences in crop residues, N inputs (dairy manure and inorganic fertilizer), timing of N amendment applications and environmental conditions influenced N2O emissions from no-till soil planted to corn (Zea mays L.). A two-year field study was carried out as part of the Pennsylvania State Sustainable Dairy Cropping Systems Experiment, where corn was planted following annual grain crops, perennial forages, and a green manure legume crop; all were amended with dairy manure. In the corn-soybean (Glycine max (L.) Merr.) rotation, N sources (dairy manure and inorganic fertilizer) and two methods of manure application (broadcasted and injected) were also compared.Chapter 1 reviews the scientific literature; describing the biotic and abiotic processes of N2O production in soils, summarizing current research on N2O emissions in agricultural systems, and emphasizing the main management and environmental drivers contributing to the emissions. This chapter reviews methods for matching N supply with crop demand, coupling N flow cycles, using advanced fertilizer techniques, and optimizing tillage management. Also, the applicability and limitations of current research to effectively reduce N2O emissions in a variety of regions are discussed.Chapter 2 analyzes the effect of corn production management practices and environmental conditions contributing to N2O in the Pennsylvania State Sustainable Dairy Cropping Systems Experiment. Significantly higher N2O emissions were observed 15-42 days after manure injection and 1-4 days after mid-season UAN application. Manure injection had 2-3 times greater potential for N2O emissions compared to broadcast manure during this time period. Integration of legumes and grasses in the cropping system reduced inorganic fertilizer use compared to soybean with manure or UAN, however, direct N2O emissions were not reduced. The Random Forest method was used to identify and rank the predictor variables for N2O emissions. The most important variables driving N2O emissions were: time after manure application, time after previous crop termination, soil nitrate, and moisture. These field research results support earlier recommendations for reducing N losses including timing N inputs close to crop uptake, and avoiding N applications when there is a high chance of precipitation to reduce nitrate accumulation in the soil and potential N losses from denitrification.Chapter 3 reports the comparison of N2O fluxes predicted with the biogeochemical model DAYCENT compared to measured data from the two-year dairy cropping systems study. Daily N2O emissions simulated by DAYCENT had between 41% and 76% agreement with measured daily N2O emissions in 2015 and 2016. DAYCENT overestimated the residual inorganic N fertilizer impact on N2O emissions in the corn following soybean with inorganic fertilizer and broadcast manure. Comparisons between DAYCENT simulated and measured N2O fluxes indicate that DAYCENT did not represent well organic N amendments from crop residues of perennials and legume cover crops, or manure application in no-till dairy systems. DAYCENT was generally able to reproduce temporal patterns of soil temperature, but volumetric soil water contents (VSWC) predicted by DAYCENT were generally lower than measured values. After precipitation events, DAYCENT predicted that VSWC tended to rapidly decrease and drain to deeper layers. Both the simulated and measured soil inorganic N increased with N fertilizer addition; however, the model tended to underestimate soil inorganic N concentration in the 0-5 cm layer. Our results suggest that DAYCENT overestimated the residual N impact of inorganic fertilizer on N2O emissions and mineralization of organic residues and nitrification happened faster than DAYCENT predicted. Chapter 4 highlights the impact of manure injection and the importance of timing organic N amendments from manures and/or crop residue with crop N uptake to mitigate N2O emissions. More research is needed to better understand the tradeoffs of these strategies in no till dairy cropping systems to help farmers in their operational management decisions. Improving the parametrization of DAYCENT for dairy cropping systems in no-till systems with high surface legume crop residues from perennials and cover crops, will make the model a more useful tool for testing different mitigation scenarios for farmers and policy-designer decision making.
Author: Yash P. Abrol
Publisher: Elsevier
ISBN: 0128119047
Category : Science
Languages : en
Pages : 570
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Book Description
The Indian Nitrogen Assessment: Sources of Reactive Nitrogen, Environmental and Climate Effects, and Management Options and Policies provides a reference for anyone interested in Reactive N, from researchers and students, to environmental managers. Although the main processes that affect the N cycle are well known, this book is focused on the causes and effects of disruption in the N cycle, specifically in India. The book helps readers gain a precise understanding of the scale of nitrogen use, misuse, and release through various agricultural, industrial, vehicular, and other activities, also including discussions on its contribution to the pollution of water and air. Drawing upon the collective work of the Indian Nitrogen Group, this reference book helps solve the challenges associated with providing reliable estimates of nitrogen transfers within different ecosystems, also presenting the next steps that should be taken in the development of balanced, cost-effective, and feasible strategies to reduce the amount of reactive nitrogen. - Identifies all significant sources of reactive nitrogen flows and their contribution to the nitrogen-cycle on a national, regional, and global level - Covers nitrogen management across sectors, including the environment, food security, energy, and health - Provides a single reference on reactive nitrogen in India to help in a number of activities, including the evaluation, analysis, synthesis, documentation, and communications on reactive nitrogen
Author: Food and Agriculture Organization of the United Nations
Publisher: Food & Agriculture Org.
ISBN: 925107920X
Category : Technology & Engineering
Languages : en
Pages : 139
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Book Description
Greenhouse gas emissions by the livestock sector could be cut by as much as 30 percent through the wider use of existing best practices and technologies. FAO conducted a detailed analysis of GHG emissions at multiple stages of various livestock supply chains, including the production and transport of animal feed, on-farm energy use, emissions from animal digestion and manure decay, as well as the post-slaughter transport, refrigeration and packaging of animal products. This report represents the most comprehensive estimate made to-date of livestocks contribution to global warming as well as the sectors potential to help tackle the problem. This publication is aimed at professionals in food and agriculture as well as policy makers.
Author: Charlotte Decock
Publisher:
ISBN: 9781267398338
Category :
Languages : en
Pages :
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Book Description
Agricultural soils encompass one of the major sources of anthropogenic nitrous oxide (N2O), a potent greenhouse gas and stratospheric ozone depleting substance. Therefore, accurate prediction of N2O emissions from soils and development of effective mitigation strategies are pertinent. However, the scientific understanding of mechanisms underlying N2O emissions is limited, in part, by the lack of suitable methods to assess sources of N2O, especially under field conditions and in undisturbed soil cores. In this dissertation, two ecological applications of source-partitioning N2O were considered: (1) the feedback of N2O emissions to elevated atmospheric CO2 and tropospheric O3 and (2) mechanisms underlying N2O emissions during a simulated rainfall event in a tomato cropping system in California. Furthermore, four methods were evaluated for their utility in source-partitioning N2O with minimal disturbance of the system: (1) tracing of added 15N enriched NH4 and/or NO3− to N2O, (2) use of natural abundance 15N of N2O and its precursors, (3) measuring the intramolecular distribution of 15N in N2O, expressed as site preference (SP), and (4) determining relationships between natural abundance 18O and 15N. Method comparisons elucidated that the use of isotope models that include all natural abundance isotopes of N2O and its precursors and uncertainty deductions for isotope fractionation factors to estimate N transformation rates and sources of N2O during peak N2O emissions is the most promising approach to improve our understanding of mechanisms underlying N2O emissions with minimal sampling-associated disturbance of the system. Various approaches to study sources of N2O and N-cycling suggested that elevated CO2 and O3 will unlikely cause a feedback on global climate change through altered N2O emissions in soybean agroecosystems in the Midwestern USA. Furthermore, elevated CO2 decelerated, whereas elevated O3 accelerated N-cycling if integrated over longer time scales. In a California tomato cropping system, N2O reduction to N2 decreased progressively as soil dried out following wetting up. Overall, this dissertation illustrates the added benefit of studying mechanisms underlying N2O emissions in addition to field N2O fluxes per se and encourages further research to source-partition N2O emissions and its needed methodology to understand N2O responses of agroecosystems in a changing global environment.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309168643
Category : Science
Languages : en
Pages : 286
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Book Description
Air Emissions from Animal Feeding Operations: Current Knowledge, Future Needs discusses the need for the U.S. Environmental Protection Agency to implement a new method for estimating the amount of ammonia, nitrous oxide, methane, and other pollutants emitted from livestock and poultry farms, and for determining how these emissions are dispersed in the atmosphere. The committee calls for the EPA and the U.S. Department of Agriculture to establish a joint council to coordinate and oversee short - and long-term research to estimate emissions from animal feeding operations accurately and to develop mitigation strategies. Their recommendation was for the joint council to focus its efforts first on those pollutants that pose the greatest risk to the environment and public health.
Author: Gina Marie Garland
Publisher:
ISBN: 9781267023544
Category :
Languages : en
Pages :
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Book Description
Nitrous oxide (N2O) is a powerful greenhouse gas (GHG) produced from soils. It is a natural component of the nitrogen (N) cycle, but emissions are rising due to the increased use of both organic and synthetic N fertilizers in agricultural production systems over the past century. As atmospheric concentrations of N2O continue to climb, its influence on global warming and climate change cannot be denied. Because N2O is produced during soil microbial processes, agricultural production has a great influence on these processes by shaping the soil environment and thus how the microbes are able to process available N. Therefore, knowing the underlying practices responsible for current GHG emissions is necessary to develop best management practices aimed at reducing N2O emissions. Two studies were conducted in a vineyard in Northern California in order to determine how management practices (both conventional and alternative) as well as climatic conditions affect annual and seasonal nitrous oxide emissions within Mediterranean vineyard cropping systems. N2O fluxes were measured using a closed flux chamber method for several days following each management and precipitation event. Furthermore, soil samples were collected to relate N2O emissions with water-filled pore space (WFPS), inorganic N concentration (NO3 and NH4), dissolved organic carbon (DOC), and pH. Cumulative N2O emissions in the no-till (NT) system were greater under both the vine and the tractor row compared to conventional till (CT), with 0.15 ± 0.026 kg N2O-N ha−1 growing season−1 emitted from the CT vine compared to 0.22 ± 0.032 kg N2O-N ha−1 growing season−1 emitted from the NT vine and 0.13 ± 0.048 kg N2O-N ha−1 growing season−1 emitted from the CT row compared to 0.19 ± 0.019 kg N2O-N ha−1 growing season−1 from the NT row. Yet these variations were not significant, indicating no differences in seasonal N2O emissions following conversion from CT to NT compared to long-term CT management. Total annual emissions in the first year, when a leguminous cover crop was planted in the tractor row, totaled 3.92 kg N2O-N ha−1, while emissions in the second year when the tractor rows were fallow showed a 7-fold reduction, reaching only 0.56 kg N2O-N ha−1. During the growing season, fertilization events produced slightly increased emissions compared to the low background values. However, the largest fluxes occurred during the fallow season, in response to the first precipitation event of the year, especially in the tractor rows. Surprisingly, precipitation events in the second year, when the tractor rows were fallow, did not follow the same pattern, indicating the significant influence of the cover crop-derived N on annual N2O emissions. By and large, these studies show that agricultural management practices do have a direct influence on N2O emissions, and that their interaction with climatic conditions greatly influences total N2O emissions within a Mediterranean vineyard cropping system. Furthermore, the vastly increased N2O emissions following leguminous cover crop addition highlights the need to assess the environmental impacts of leguminous cover crops in systems where a crop does not directly follow legume incorporation.
Author: Food and Agriculture Organization of the United Nations
Publisher: Food & Agriculture Org.
ISBN: 9789251044506
Category : Business & Economics
Languages : en
Pages : 44
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Book Description
This is a joint study involving five organisations from both the public and private sectors. The objective is to explore the future need for fertilizer required to support the Food and Agriculture Organization's (FAO) projections of agricultural commodity production for 2015 and 2030. The paper begins by briefly reviewing attempts to identify and quantify the factors influencing the growth in demand and supply for agricultural commodities. Several studies that estimate long-term fertlizer use are also reviewed, followed by a discussion of the forecasting methods and data. The results and implications conclude the paper. The study projects growth rates of between 0.7 and 1.3 per cent, depending on assumptions about nutrient efficiency over the next 35 years
Author: Pierre J. Gerber
Publisher: Food & Agriculture Organization of the UN (FAO)
ISBN:
Category : Nature
Languages : en
Pages : 240
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Book Description
The current analysis was conducted to evaluate the potential of nutritional, manure and animal husbandry practices for mitigating methane (CH4) and nitrous oxide (N2O) - i.e. non-carbon dioxide (CO2) - GHG emissions from livestock production. These practices were categorized into enteric CH4, manure management and animal husbandry mitigation practices. Emphasis was placed on enteric CH4 mitigation practices for ruminant animals (only in vivo studies were considered) and manure mitigation practices for both ruminant and monogastric species. Over 900 references were reviewed; simulation and life cycle assessment analyses were generally excluded
Author: Tom Misselbrook
Publisher: Frontiers Media SA
ISBN: 288963227X
Category :
Languages : en
Pages : 249
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Book Description
This eBook presents highlight papers from the 17th International conference of the Recycling of Agricultural, Municipal and Industrial Residues to Agriculture Network (RAMIRAN) that was held in Wexford, Ireland in September 2017. The book contains a broad range of papers around this multidisciplinary theme covering topics including regional and national organic resource use planning, impact of livestock diet on manure composition, fate and utilisation of excreta from grazing livestock, anaerobic digestion, overcoming barriers to resource reuse, hygienic aspects of residue recycling and impacts on soil health. The overarching theme being addressed is the sustainable recycling of organic residues to agriculture, to promote effective nutrient use and minimise environmental impact.
