37 results
Appropriateness of antibiotic use in patients with and without altered mental status diagnosed with a urinary tract infection
- Connor M. Anderson, Jeremy D. VanHoose, Donna R. Burgess, David S. Burgess, Aric Schadler, J. Zachary Porterfield, Katie L. Wallace
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- Journal:
- Antimicrobial Stewardship & Healthcare Epidemiology / Volume 2 / Issue 1 / 2022
- Published online by Cambridge University Press:
- 13 December 2022, e198
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Objective:
The objective of this study was to determine antibiotic appropriateness based on Loeb minimum criteria (LMC) in patients with and without altered mental status (AMS).
Design:Retrospective, quasi-experimental study assessing pooled data from 3 periods pertaining to the implementation of a UTI management guideline.
Setting:Academic medical center in Lexington, Kentucky.
Patients:Adult patients aged ≥18 years with a collected urinalysis receiving antimicrobial therapy for a UTI indication.
Methods:Appropriateness of UTI management was assessed in patients prior to an institutional UTI guideline, after guideline introduction and education, and after implementation of a prospective audit-and-feedback stewardship intervention from September to November 2017–2019. Patient data were pooled and compared between patients noted to have AMS versus those with classic UTI symptoms. Loeb minimum criteria were used to determine whether UTI diagnosis and treatment was warranted.
Results:In total, 600 patients were included in the study. AMS was one of the most common indications for testing across the 3 periods (19%–30.5%). Among those with AMS, 25 patients (16.7%) met LMC, significantly less than the 151 points (33.6%) without AMS (P < .001).
Conclusions:Patients with AMS are prescribed antibiotic therapy without symptoms indicative of UTI at a higher rate than those without AMS, according to LMC. Further antimicrobial stewardship efforts should focus on prescriber education and development of clearly defined criteria for patients with and without AMS.
Hyperglycemia in pregnancy and developmental outcomes in children at 18–60 months of age: the PANDORA Wave 1 study
- Angela Titmuss, Anita D’Aprano, Federica Barzi, Alex D.H. Brown, Anna Wood, Christine Connors, Jacqueline A. Boyle, Elizabeth Moore, Kerin OʼDea, Jeremy Oats, H. David McIntyre, Paul Zimmet, Jonathan E. Shaw, Maria E. Craig, Louise J. Maple-Brown
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- Journal:
- Journal of Developmental Origins of Health and Disease / Volume 13 / Issue 6 / December 2022
- Published online by Cambridge University Press:
- 04 April 2022, pp. 695-705
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This study aimed to explore the association between hyperglycemia in pregnancy (type 2 diabetes (T2D) and gestational diabetes mellitus (GDM)) and child developmental risk in Europid and Aboriginal women.
PANDORA is a longitudinal birth cohort recruited from a hyperglycemia in pregnancy register, and from normoglycemic women in antenatal clinics. The Wave 1 substudy included 308 children who completed developmental and behavioral screening between age 18 and 60 months. Developmental risk was assessed using the Ages and Stages Questionnaire (ASQ) or equivalent modified ASQ for use with Aboriginal children. Emotional and behavioral risk was assessed using the Strengths and Difficulties Questionnaire. Multivariable logistic regression was used to assess the association between developmental scores and explanatory variables, including maternal T2D in pregnancy or GDM.
After adjustment for ethnicity, maternal and child variables, and socioeconomic measures, maternal hyperglycemia was associated with increased developmental “concern” (defined as score ≥1 SD below mean) in the fine motor (T2D odds ratio (OR) 5.30, 95% CI 1.77–15.80; GDM OR 3.96, 95% CI 1.55–10.11) and problem-solving (T2D OR 2.71, 95% CI 1.05–6.98; GDM OR 2.54, 95% CI 1.17–5.54) domains, as well as increased “risk” (score ≥2 SD below mean) in at least one domain (T2D OR 5.33, 95% CI 1.85–15.39; GDM OR 4.86, 95% CI 1.95–12.10). Higher maternal education was associated with reduced concern in the problem-solving domain (OR 0.27, 95% CI 0.11–0.69) after adjustment for maternal hyperglycemia.
Maternal hyperglycemia is associated with increased developmental concern and may be a potential target for intervention so as to optimize developmental trajectories.
Chapter 11 - Policy, Financing and Implementation
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- By Catherine Mitchell, Janet L. Sawin, Govind R. Pokharel, Daniel Kammen, Zhongying Wang, Solomone Fifita, Mark Jaccard, Ole Langniss, Hugo Lucas, Alain Nadai, Ramiro Trujillo Blanco, Eric Usher, Aviel Verbruggen, Rolf Wüstenhagen, Kaoru Yamaguchi, Douglas Arent, Greg Arrowsmith, Morgan Bazilian, Lori Bird, Thomas Boermans, Alex Bowen, Sylvia Breukers, Thomas Bruckner, Sebastian Busch, Elisabeth Clemens, Peter Connor, Felix Creutzig, Peter Droege, Karin Ericsson, Chris Greacen, Renata Grisoli, Erik Haites, Kirsty Hamilton, Jochen Harnisch, Cameron Hepburn, Suzanne Hunt, Matthias Kalkuhl, Heleen de Koninck, Patrick Lamers, Birger Madsen, Gregory Nemet, Lars J. Nilsson, Supachai Panitchpakdi, David Popp, Anis Radzi, Gustav Resch, Sven Schimschar, Kristin Seyboth, Sergio Trindade, Bernhard Truffer, Sarah Truitt, Dan van der Horst, Saskia Vermeylen, Charles Wilson, Ryan Wiser, David de Jager, Antonina Ivanova Boncheva
- Edited by Ottmar Edenhofer, Ramón Pichs-Madruga, Youba Sokona, Kristin Seyboth, Susanne Kadner, Timm Zwickel, Patrick Eickemeier, Gerrit Hansen, Steffen Schlömer, Christoph von Stechow, Patrick Matschoss
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- Book:
- Renewable Energy Sources and Climate Change Mitigation
- Published online:
- 05 December 2011
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- 21 November 2011, pp 865-950
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Summary
Executive Summary
Renewable energy can provide a host of benefits to society. In addition to the reduction of carbon dioxide (CO2) emissions, governments have enacted renewable energy (RE) policies to meet a number of objectives including the creation of local environmental and health benefits; facilitation of energy access, particularly for rural areas; advancement of energy security goals by diversifying the portfolio of energy technologies and resources; and improving social and economic development through potential employment opportunities. Energy access and social and economic development have been the primary drivers in developing countries whereas ensuring a secure energy supply and environmental concerns have been most important in developed countries.
An increasing number and variety of RE policies–motivated by a variety of factors–have driven substantial growth of RE technologies in recent years. Government policies have played a crucial role in accelerating the deployment of RE technologies. At the same time, not all RE policies have proven effective and efficient in rapidly or substantially increasing RE deployment. The focus of policies is broadening from a concentration almost entirely on RE electricity to include RE heating and cooling and transportation.
RE policies have promoted an increase in RE capacity installations by helping to overcome various barriers. Barriers specific to RE policymaking (e.g., a lack of information and awareness), to implementation (e.g., a lack of an educated and trained workforce to match developing RE technologies) and to financing (e.g., market failures) may further impede deployment of RE.
Contributors
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- By Aakash Agarwala, Linda S. Aglio, Rae M. Allain, Paul D. Allen, Houman Amirfarzan, Yasodananda Kumar Areti, Amit Asopa, Edwin G. Avery, Patricia R. Bachiller, Angela M. Bader, Rana Badr, Sibinka Bajic, David J. Baker, Sheila R. Barnett, Rena Beckerly, Lorenzo Berra, Walter Bethune, Sascha S. Beutler, Tarun Bhalla, Edward A. Bittner, Jonathan D. Bloom, Alina V. Bodas, Lina M. Bolanos-Diaz, Ruma R. Bose, Jan Boublik, John P. Broadnax, Jason C. Brookman, Meredith R. Brooks, Roland Brusseau, Ethan O. Bryson, Linda A. Bulich, Kenji Butterfield, William R. Camann, Denise M. Chan, Theresa S. Chang, Jonathan E. Charnin, Mark Chrostowski, Fred Cobey, Adam B. Collins, Mercedes A. Concepcion, Christopher W. Connor, Bronwyn Cooper, Jeffrey B. Cooper, Martha Cordoba-Amorocho, Stephen B. Corn, Darin J. Correll, Gregory J. Crosby, Lisa J. Crossley, Deborah J. Culley, Tomas Cvrk, Michael N. D'Ambra, Michael Decker, Daniel F. Dedrick, Mark Dershwitz, Francis X. Dillon, Pradeep Dinakar, Alimorad G. Djalali, D. John Doyle, Lambertus Drop, Ian F. Dunn, Theodore E. Dushane, Sunil Eappen, Thomas Edrich, Jesse M. Ehrenfeld, Jason M. Erlich, Lucinda L. Everett, Elliott S. Farber, Khaldoun Faris, Eddy M. Feliz, Massimo Ferrigno, Richard S. Field, Michael G. Fitzsimons, Hugh L. Flanagan Jr., Vladimir Formanek, Amanda A. Fox, John A. Fox, Gyorgy Frendl, Tanja S. Frey, Samuel M. Galvagno Jr., Edward R. Garcia, Jonathan D. Gates, Cosmin Gauran, Brian J. Gelfand, Simon Gelman, Alexander C. Gerhart, Peter Gerner, Omid Ghalambor, Christopher J. Gilligan, Christian D. Gonzalez, Noah E. Gordon, William B. Gormley, Thomas J. Graetz, Wendy L. Gross, Amit Gupta, James P. Hardy, Seetharaman Hariharan, Miriam Harnett, Philip M. Hartigan, Joaquim M. Havens, Bishr Haydar, Stephen O. Heard, James L. Helstrom, David L. Hepner, McCallum R. Hoyt, Robert N. Jamison, Karinne Jervis, Stephanie B. Jones, Swaminathan Karthik, Richard M. Kaufman, Shubjeet Kaur, Lee A. Kearse Jr., John C. Keel, Scott D. Kelley, Albert H. Kim, Amy L. Kim, Grace Y. Kim, Robert J. Klickovich, Robert M. Knapp, Bhavani S. Kodali, Rahul Koka, Alina Lazar, Laura H. Leduc, Stanley Leeson, Lisa R. Leffert, Scott A. LeGrand, Patricio Leyton, J. Lance Lichtor, John Lin, Alvaro A. Macias, Karan Madan, Sohail K. Mahboobi, Devi Mahendran, Christine Mai, Sayeed Malek, S. Rao Mallampati, Thomas J. Mancuso, Ramon Martin, Matthew C. Martinez, J. A. Jeevendra Martyn, Kai Matthes, Tommaso Mauri, Mary Ellen McCann, Shannon S. McKenna, Dennis J. McNicholl, Abdel-Kader Mehio, Thor C. Milland, Tonya L. K. Miller, John D. Mitchell, K. Annette Mizuguchi, Naila Moghul, David R. Moss, Ross J. Musumeci, Naveen Nathan, Ju-Mei Ng, Liem C. Nguyen, Ervant Nishanian, Martina Nowak, Ala Nozari, Michael Nurok, Arti Ori, Rafael A. Ortega, Amy J. Ortman, David Oxman, Arvind Palanisamy, Carlo Pancaro, Lisbeth Lopez Pappas, Benjamin Parish, Samuel Park, Deborah S. Pederson, Beverly K. Philip, James H. Philip, Silvia Pivi, Stephen D. Pratt, Douglas E. Raines, Stephen L. Ratcliff, James P. Rathmell, J. Taylor Reed, Elizabeth M. Rickerson, Selwyn O. Rogers Jr., Thomas M. Romanelli, William H. Rosenblatt, Carl E. Rosow, Edgar L. Ross, J. Victor Ryckman, Mônica M. Sá Rêgo, Nicholas Sadovnikoff, Warren S. Sandberg, Annette Y. Schure, B. Scott Segal, Navil F. Sethna, Swapneel K. Shah, Shaheen F. Shaikh, Fred E. Shapiro, Torin D. Shear, Prem S. Shekar, Stanton K. Shernan, Naomi Shimizu, Douglas C. Shook, Kamal K. Sikka, Pankaj K. Sikka, David A. Silver, Jeffrey H. Silverstein, Emily A. Singer, Ken Solt, Spiro G. Spanakis, Wolfgang Steudel, Matthias Stopfkuchen-Evans, Michael P. Storey, Gary R. Strichartz, Balachundhar Subramaniam, Wariya Sukhupragarn, John Summers, Shine Sun, Eswar Sundar, Sugantha Sundar, Neelakantan Sunder, Faraz Syed, Usha B. Tedrow, Nelson L. Thaemert, George P. Topulos, Lawrence C. Tsen, Richard D. Urman, Charles A. Vacanti, Francis X. Vacanti, Joshua C. Vacanti, Assia Valovska, Ivan T. Valovski, Mary Ann Vann, Susan Vassallo, Anasuya Vasudevan, Kamen V. Vlassakov, Gian Paolo Volpato, Essi M. Vulli, J. Matthias Walz, Jingping Wang, James F. Watkins, Maxwell Weinmann, Sharon L. Wetherall, Mallory Williams, Sarah H. Wiser, Zhiling Xiong, Warren M. Zapol, Jie Zhou
- Edited by Charles Vacanti, Scott Segal, Pankaj Sikka, Richard Urman
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- Essential Clinical Anesthesia
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- 05 January 2012
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- 11 July 2011, pp xv-xxviii
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Index
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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- 05 June 2012
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- 28 April 2011, pp 546-556
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References
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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- 28 April 2011, pp 516-545
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17 - Technological change in high-yield crop agriculture
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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- 28 April 2011, pp 458-483
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Summary
In the last half century, Earth's population has increased two-fold while land used to produce food, livestock feed, and fiber crops rose by only 13%. This considerable achievement has been called a green revolution made possible by a powerful combination of new technologies, including genetic improvement of major staple food crops, development and widespread use of mineral fertilizers and pesticides, and expansion of irrigated area. The result is that a few high-yield cropping systems now provide the major portion of human food from a relatively small area of arable land (Chapter 1.2). While these developments have had remarkable success in raising productivity and sparing natural ecosystems from conversion to agriculture, there are nonetheless growing concerns about negative environmental impacts. Here we learn how rapid technological advancement enabled conversion to high-yield systems and consider future challenges to sustaining them and their high productivity.
Common features of high-yield systems
High-yield cropping systems have evolved through intensification of traditional systems during the past 50 years. This process involved: (i) producing more crops per year per unit land area, i.e., temporal intensification; and (ii) more intensive use of inputs (fertilizers, manure, irrigation, pesticides) to alleviate yield-limiting abiotic and biotic stresses, i.e., input intensification. High-yield systems are not only found in developed countries where large-scale, mechanized agriculture predominates, but also in developing countries where small-scale, labor-intensive systems remain the norm. Examples of the latter include continuous rice, rice–wheat, and cotton and sugarcane systems in developing countries of south, southeast, and east Asia.
Part V - Farming past, present, and future
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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- 05 June 2012
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- 28 April 2011, pp 437-438
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Summary
In the first edition of this book, published in 1992, we presented two case studies of important farming systems, wheat–sheep farming in southern Australia and maize–beef production in central USA, discussing how they operated based on current knowledge, technology, and economic conditions. The purpose was to integrate the knowledge and principles presented in earlier chapters and show how success in farming depends upon this integration. Economic survival required a sustainable system, which could be analyzed in terms of balances of water, nutrients, and capital. In addition, farmers had to be nimble in adapting to variable climatic and economic environments. We also hoped that those analyses would serve to encourage readers to make detailed analyses of other farming systems. Those examples remain available to readers on the internet and can continue to meet those goals. However, and unsurprisingly, these analyses are substantially out of date with regard to current cropping systems in those regions. Knowledge and technology have advanced rapidly, global population and demand for agricultural products have increased substantially, and economic conditions have changed dramatically.
In this edition we wish to emphasize that dynamic nature of agricultural and farming systems and stress how developments in technology have and will continue to provide farmers with the capacity to remain economically viable over the short term, and sustainable over the longer term. For this we present two new chapters. Chapter 16 examines the development of wheat production systems in southern Australia since inception of the industry in 1850.
4 - Genetic resources
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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Summary
Crop plants carry information acquired during their evolution and breeding that determines their performance in agricultural fields. That information is held in the genetic material of living plants and is subject to change through mutation and through recombination into new patterns, and can be lost. Proper management of this resource involves knowing the capabilities of germplasms, maintaining and improving their genetic constitution, and employing them advantageously in farming.
The terminology relating to genetic resources is in a state of flux. Here we use germplasm to denote the totality of genes and genetic combinations found in a species, or a major portion of it. A genetic population (sometimes “line” or “strain”) describes a smaller group of individuals (plants or seed) that share common ancestry and genes, and thus common traits. This use of the term population differs from that of population ecologists, who use it to denote closely related individuals that cohabit in time and space.
Genetic diversity in agriculture
Genetic diversity in farming can be defined at several levels. Here we deal with diversity of species and cultivars.
Species diversity
Thousands of plant species have been cultivated at some time or place, and several hundred are currently employed as crops, yet most crop production is derived from only a small number. Data presented in Table 4.1 account for most global production from arable land and permanent crops.
1 - Agricultural systems
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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Summary
Humans depend on agriculture to provide food, feed, fiber, and fuel. Production of these organic materials in individual fields depends upon the physiological abilities of plants and the soil and aerial environments in which they grow. What crops are grown, and how, are human decisions that depend upon usefulness and value of products, costs of production, and risks involved. At the farm level, those considerations are rationalized with need for animal feeds, availability of labor, and requirements for crop rotation to raise fertility and control disease, weeds, or erosion. Additional constraints are imposed by market forces and availability of capital and technology.
Within these socioeconomic considerations, crop response to environment and management follows the laws of thermodyamics and conservation of energy and mass. Therefore, we can understand and predict crop performance using ecological analyses in terms of biological, chemical, and physical principles. This is the context and content of crop ecology.
In this chapter, we introduce ideas about the nature, objectives, and management of farming to provide a foundation for detailed analyses of crop performance in agricultural systems. We also present the guiding principles upon which this book is constructed.
On the nature of agriculture
Agriculture can be studied at various organizational and geospatial levels, from individual fields, to their grouping in farms, and to grouping of farms within regions. This is illustrated in Fig. 1.1 and identifies the need to establish a coherent terminology.
3 - Community concepts
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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Summary
Crop communities can be described in simple terms. Species and cultivar define genetic content while density, spacing pattern, plant size, and stage of development define structure. The type of community is termed a monoculture when only one crop species is grown in a field at a time; the terms polyculture and mixed cropping apply to communities with two or more cohabiting crop species. Other definitions and terms exist but these are the traditional ones employed by agronomists. Most arable farming involves rotations of monocultures over time whereas pastures are mostly polycultures.
Critical issues in crop ecology, which we will examine in detail in this chapter, include the impact of community structure on resource capture and yield of crop production systems and interactions between component plants.
Community change
Concepts of community structure evolved from complementary work by agronomists who study managed communities and by botanists concerned with natural communities. In agriculture, small differences in production are important and agronomists study how production rate, competition, limiting factors, and genetic expression influence behavior of simple communities. Botanists, faced with highly diverse, natural systems give greater attention to community species composition in relation to adaptive traits and evolution. A background in plant ecology is useful for agriculturalists, and vice versa. Natural communities are subject to continuing change as different species of plants invade a site and displace earlier occupants. This process is termed succession and the sequence followed, the sere.
Contents
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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- 28 April 2011, pp v-x
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2 - Trophic chains
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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Summary
Plants provide all energy for maintenance, growth, reproduction, and locomotion of every living organism on our planet. That energy, originating from the Sun, flows from plants through a web of herbivores, carnivores, and decomposers. This trophic chain – “who eats whom” – gradually returns carrier CO2 molecules to the atmosphere. Fires, occurring naturally from lightening strikes, or provoked by human activities, are a more sudden, but chemically similar, release of solar energy accumulated by plants.
Humans and some other animals also use plant material (biomass) for construction but humans alone have combusted them under controlled conditions to provide heat for warmth, cooking, and both stationary power and traction. Once, animals were the only source of traction and, in the eighteenth century, consumed as much as one third of agricultural production. Biomass accumulated by plants during previous geological periods formed coal and oil (fossil fuels) that have driven the development of transportation, agriculture, and industry during recent centuries.
Agricultural systems have developed predominantly to provide food for humans in plant and animal products, but they also provide fiber and fuel. This chapter describes the chemical and energetic content of plant products and explains their relationship to nutritive value and carrying capacity of land for animals used in agriculture and for humans. Questions of energy use in agriculture and its potential to supply a greater proportion of society's demand for non-dietary energy, including the current focus on biofuel, are discussed further in Chapter 15.
Crop Ecology
- Productivity and Management in Agricultural Systems
- 2nd edition
- David J. Connor, Robert S. Loomis, Kenneth G. Cassman
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- 05 June 2012
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- 28 April 2011
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Food security and environmental conservation are two of the greatest challenges facing the world today. It is predicted that food production must increase by at least 70% before 2050 to support continued population growth, though the size of the world's agricultural area will remain essentially unchanged. This updated and thoroughly revised second edition provides in-depth coverage of the impact of environmental conditions and management on crops, resource requirements for productivity and effects on soil resources. The approach is explanatory and integrative, with a firm basis in environmental physics, soils, physiology and morphology. System concepts are explored in detail throughout the book, giving emphasis to quantitative approaches, management strategies and tactics employed by farmers, and associated environmental issues. Drawing on key examples and highlighting the role of science, technology and economic conditions in determining management strategies, this book is suitable for agriculturalists, ecologists and environmental scientists.
Conversions and constants useful in crop ecology
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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15 - Energy and labor
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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Summary
All human activity requires energy. The inescapable minimum is dietary energy to maintain the population. In earlier times, if each hunter-gatherer could collect around 33 MJ every day for a family unit (man, woman, and two children), then survival was possible. In practice, additional organic materials, mostly non-dietary, were needed for shelter, clothing, and combustion (cooking and warmth).
Agriculture provided a way to secure that supply, and more, with less environmental hazard and less competition from other organisms. The development and maintenance of industrialized cultures is based upon the substitution of energy for labor in mandatory activities of food provision. By success in raising and stabilizing yields, agriculture has supported an increasing population and released an increasing proportion from labor in food production. Greater participation in cultural, leisure, recreational, and scientific activities improves well-being for all and advances human civilization.
The purpose of this chapter is to explain the extent, pattern, and significance of energy use in agriculture so that we might understand how agriculture at various stages of development can respond to changes in the supply and cost of energy and labor.
Sources and utilization of energy
Earth systems capture energy that originates on Earth and beyond. Earth energy comprises a small geothermal heat flux and the essentially “limitless” nuclear energy of matter. Energy captured from outside is dominantly the flux of radiant energy originating in nuclear fusion reactions in the Sun (Section 6.1), and supported by kinetic energy in ocean currents and tides caused by gravitational forces of planetary motion.
Preface
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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Summary
Humans make extensive use of land, water, energy, labor, and other resources in the production of crops and pastures. We do this because it is essential to our survival and well-being. As world population grows, so does demand for continuing success in agriculture. And as more land is used in agriculture, concerns for loss of natural ecosystems and biodiversity increase as well. The conflict between production and conservation can only be resolved with cropping systems that are highly productive, efficient, and sustainable.
Agricultural management involves plant communities and areas of land. It requires knowledge of individual plant behavior under crowded conditions and interactions of plant communities with aerial and soil environments. These organismal and higher levels of biological organization are the subjects of ecology at different spatial scales, but explanation of these behaviors depends upon integration of relevant knowledge spanning lower levels from molecules and cells to organs. Ecology can thus be characterized as an integration of other disciplines. In turn, however, it provides specialist disciplines with context and relevance and, further, explains that in isolation they rarely affect system outcome. Crop ecology has additional dimensions in agricultural technology that interface with engineering, information and social sciences, and perspectives provided through history.
7 - Soil resources
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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Summary
Soils are formed in situ over long periods under the influences of climate and vegetation during which they develop characteristic vertical profiles. Inorganic materials are the major component of soils. These include partially weathered parent materials, secondary minerals, and dissolved salts. Other components are air, water, organic matter in various stages of decay (with the most reduced form called humus), and living organisms including plant roots. Typical agricultural soils have a bulk density (dry mass per unit volume) near 1.3 g cm−3 [1300 kg m−3 or 13 × 106 kg (m depth)−1 ha−1]. Organic matter ranges by mass from 1 to 5% in mineral soils, and can be 80% or more in peaty soils. In typical mineral soils, water content at drained capacity accounts for 0.1 to 0.4 times the soil volume but some organic and volcanic soils hold much more. Understanding the physical, chemical, and biological properties of soils as media for plant growth provides insight into plant adaptations to soil conditions and crop management practices to overcome soil-related constraints.
Soil chemistry
We begin with a review of several concepts important to the study of soils and crops. Familiarity with these concepts is fundamental to crop ecology. Soil composition is dominated by an abundance of insoluble compounds of aluminum, silicon, and calcium, and soil chemistry centers on interactions between those solids and the water phase, called the soil solution.
Frontmatter
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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Species list
- David J. Connor, University of Melbourne, Robert S. Loomis, University of California, Davis, Kenneth G. Cassman, University of Nebraska, Lincoln
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- Crop Ecology
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