Download or read book Influence of Nitrogen and Phosphorus on Interference Between Medusahead and Squirreltail written by Kert R. Young and published by . This book was released on 2006 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Restoration of invaded aridlands is required to reduce the exorbitant ecological and monetary losses related to noxious weeds. An understanding of how reduced and increased levels of soil N and P influence interference between medusahead and squirreltail is imperative to understanding how squirreltail may be used in restoration of medusahead infested rangelands. Medusahead (Taeniatherum caput-medusae ssp. asperum (Simk.) Melderis) is an invasive, nonnative, annual grass that is rapidly displacing desirable rangeland plants in western North America. Evidence suggests that the native, perennial bunchgrass squirreltail (Elymus elymoides (Raf.) Swezey) may be able to displace medusahead under certain conditions, but the role of soil nutrients in this process is not well understood. I performed interference and growth analysis studies in a greenhouse to determine if soil nitrogen (N) and phosphorus (P) alter interference between medusahead and squirreltail. In both studies, plants were grown in pots containing a one-to-one mixture of sand and field soil from a site containing medusahead and squirreltail. In the interference experiment, medusahead and squirreltail were Redacted for privacy planted in density combinations of 0, 1, 5, 25, and 125 seeds per species per pot at four levels of N and P (loNloP, loNhiP, hiNloP, hiNhiP). Results indicated that medusahead and squirreltail competed for N. Increased soil N reduced medusahead and squirreltail's relative competitive abilities largely due to reductions in the intensity of intraspecific interference. High N also reduced the effect of medusahead density on squirreltail biomass. Soil P levels had little influence on predicted species aboveground growth or relative competitive ability. In the growth analysis experiment, plant growth, growth rates, and relative growth rates for above- and belowground biomass, total biomass, leaf area, total root length, and depth of root penetration of isolated individuals were recorded for harvested plants at 2-week intervals over a 70-day period. Results indicated that medusahead produced more absolute belowground biomass, aboveground biomass, total biomass, leaf area, and root length and had higher growth rates for these parameters than squirreltail. Squirreltail allocated more of its acquired resources to belowground growth endowing it with greater root: shoot ratios. Medusahead relative growth rates decreased in belowground biomass, aboveground biomass, total biomass, leaf area, and root length over the course of the study period, while squirreltail's relative growth rate for leaf area remained constant; however, medusahead still maintained higher relative leaf area growth rates during the experiment. Results from the growth analysis study matched results from the interference study in that medusahead was found to be a superior competitor over squirreltail for environmental resources. In order to understand the full benefits of squirreltail's relatively higher allocation of biomass to belowground growth, a long-term study would be necessary. A long-term study would allow for the differences in perennial versus annual resource allocation patterns to manifest themselves to their fullest extent. Over time and with consistently low nutrient availability, squirreltail might increase in medusahead infested rangelands. The maintenance of continually low levels of nutrient availability combined with a reduction of medusahead competition are prerequisites for reclamation of medusahead infested rangelands. Maintaining soil N at very low levels, over the long term, may diminish medusahead seed banks to low enough levels that squirreltail can increase and slowly replace medusahead. Competition between medusahead and squirreltail seedlings will likely be won by medusahead, but seedling-to- mature plant competition may be won by squirreltail. It appears that management inputs, e.g., seed drilling, herbicides, and best management practices that maintain low N availability, will be required to allow native perennials to firmly establish in invasive annual weed infested rangelands.
Download or read book Weed Technology written by and published by . This book was released on 2005 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Weed Ecology written by Steven R. Radosevich and published by John Wiley & Sons. This book was released on 1997-02-05 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt: Weeds are successful plants, but on their own terms. Looking at weeds from an ecological viewpoint, emphasising the way in which one species interacts with others, the authors show that weeds are questionable mainly in that they are out-of-place.
Download or read book Perspectives on Plant Competition written by James Grace and published by Elsevier. This book was released on 2012-12-02 with total page 499 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perspectives on Plant Competition is mainly about addressing the many different perspectives in plant competition and finding a common ground among them. Its aim is that through this common ground, new theories can be created. Encompassing 20 chapters, this book is divided into three parts. Part I, Perspectives on the Determinants of Competitive Success, consists of eight chapters. This section deals mainly on the question of determination of competitive success. Different writers put forward various definitions of competition and competitive success to shed light on the question at hand. In the second part of this book, an opposing set of views regarding the consequences of competitive interactions for the plant community structure is provided. This section emphasizes the idea that competition is not the sole force in natural communities. Each chapter in this part focuses on a certain aspect of competition as seen in different communities – across and within habitats – and systems. Part III, which comprises of four chapters, focuses on the competition within the context of interaction of plants with organisms on the other trophic levels. The chapters set forth the idea that competition depends on the impacts of herbivores, parasites, and symbionts. The concluding part of the book greatly emphasizes the need to integrate the mechanisms of competition into the framework of the entire food web.
Download or read book Restoring Western Ranges and Wildlands written by Stephen B. Monsen and published by . This book was released on 2004 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Competition and Coexistence written by Ulrich Sommer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: The question "Why are there so many species?" has puzzled ecologist for a long time. Initially, an academic question, it has gained practical interest by the recent awareness of global biodiversity loss. Species diversity in local ecosystems has always been discussed in relation to the problem of competi tive exclusion and the apparent contradiction between the competitive exclu sion principle and the overwhelming richness of species found in nature. Competition as a mechanism structuring ecological communities has never been uncontroversial. Not only its importance but even its existence have been debated. On the one extreme, some ecologists have taken competi tion for granted and have used it as an explanation by default if the distribu tion of a species was more restricted than could be explained by physiology and dispersal history. For decades, competition has been a core mechanism behind popular concepts like ecological niche, succession, limiting similarity, and character displacement, among others. For some, competition has almost become synonymous with the Darwinian "struggle for existence", although simple plausibility should tell us that organisms have to struggle against much more than competitors, e.g. predators, parasites, pathogens, and envi ronmental harshness.
Download or read book Plants in Changing Environments written by F. A. Bazzaz and published by Cambridge University Press. This book was released on 1996-10-13 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the effects of disturbance, species competition and coexistence, and the processes of plant succession.
Download or read book Inherent Variation in Plant Growth written by H. Lambers and published by . This book was released on 1998 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecosystem Functioning written by Kurt Jax and published by Cambridge University Press. This book was released on 2010-09-16 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new and integrative analysis of the concept of ecosystem functioning, providing guidance for its application in conservation practice.
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1976 with total page 1964 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1975- have "data provided by National Agricultural Library, U.S. Department of Agriculture."
Download or read book Wildland Fire in Ecosystems written by and published by . This book was released on 2005 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This state-of-knowledge review about the effects of fire on soils and water can assist land and fire managers with information on the physical, chemical, and biological effects of fire needed to successfully conduct ecosystem management, and effectively inform others about the role and impacts of wildland fire. Chapter topics include the soil resource, soil physical properties and fire, soil chemistry effects, soil biology responses, the hydrologic cycle and water resources, water quality, aquatic biology, fire effects on wetland and riparian systems, fire effects models, and watershed rehabilitation.
Download or read book Stubble Mulching in the Northwest written by Theodore R. Horning and published by . This book was released on 1962 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pp. 28.
Download or read book Erosion and Sediment Control Handbook written by Steven J. Goldman and published by McGraw-Hill Companies. This book was released on 1986 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book To Spray Or Not to Spray written by and published by . This book was released on 1995 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Flora of California written by Willis Linn Jepson and published by . This book was released on 1912 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plant Strategies and Vegetation Processes written by John Philip Grime and published by . This book was released on 1979 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Warming and Biological Diversity written by Robert L. Peters and published by Yale University Press. This book was released on 1992-01-01 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: The biological effects of global warming should be of concern to all thinking individuals, for warming could cause profound disruption of natural ecosystems and could threaten many species with extinction. This important book--the first to discuss in detail the consequences of global warming for ecosystems--includes commentary by distinguished scientists on many aspects of this critical problem. Experts describe responses of animals and plants to previous climate changes, interactions between various environmental components (precipitation and soil chemistry, for example), and synergisms between climate change and human activities such as deforestation. They consider many specific ecosystems, including tropical forests, the deciduous forests of eastern North America, the forests of the Pacific Northwest, Mediterranean-type ecosystems in California, arctic tundra, and arctic marine systems. Offering discussions that are both factual and speculative, the volume points the way to future investigations of the implications of global warming.
