Dynamics of Arid-Land, Perennial Plant Populations with an Examination of Potential Causal Agents

Rigorous statistical examination of the population dynamics of a number of long-lived perennial plant species permitted an interpretation of changes in those populations and the establishment of potentially important causal agents. Survival and recruitment of six species from the mulga-zone rangelands of Western Australia varied across three climatically different periods following the removal of domestic livestock. Two species\u27 populations (Eragrostis xerophila and Maireana glomerifolia) had their rates of increase reduced by kangaroo and euro grazing. Both survival and recruitment of Eragrostis xerophila were reduced by this grazing while Maireana glomerifolia suffered reduced recruitment during all periods. These negative effects were most pronounced during the post-drought period of more normal rainfall. Three other species populations responded positively to grazing. Recruitment and survival of Eremophila spectabilis, were affected by grazing, particularly on a poor condition site, while differences in recruitment were more important for Eremophila leucophylla. Frankenia pauciflora had increased recruitment and survival during the postdrought period. The sixth species (Ptilotus obovatus) suffered increased mortality and reduced recruitment during the post-drought period. Relative rates of change in management related groups of 18 species, including the six examined in more detail, were presented as a viable addition to the analysis of trend in rangeland vegetation. Grazing by kangaroos significantly reduced the rate of recovery of destocked rangeland pastures. Site and seasonal factors affected all species populations examined. Site induced differences affected survival of all six species examined, highlighting the difficulty of replicating large scale experiments in rangeland vegetation. Different seasonal sequences (very wet, very dry, and more normal ) produced different species population responses. Populations of most species increased during the very wet, and more normal , post-drought period, but declined, or remained static, during the drought. Potentially competitive relationships were examined at one site where the complexity of juvenile plant survival responses to seasonal conditions, treatment and to neighbor-free-space suggest potential competition, but more importantly reflect a need for more detailed study. A re-examination of Danthonia caespitosa population data collected by O.B. Williams in rangeland areas of New South Wales indicates the importance of grazing by merino sheep, seasonal conditions, and the cohort within which a plant is recruited. The extreme variability of the data highlights the need for experimental designs that take account of the frequency and importance of causal agent impact, and are related to the dynamism of the population

16th Wildland Shrub Symposium Threats to Shrubland Ecosystem Integrity 2010 May 18-20 Logan, UT

Abstract: The 29 papers in this proceedings are divided into the main organized sessions of the 16th Wildland Shrub Symposium, including the plenary session to introduce the theme of threats to shrubland ecosystem integrity, impacts of energy development and reclamation on ecosystem function, invasive plant ecology. wildlife habitats: impacts and restoration opportunities, historical perspectives in shrublands, ecosystem threats due to fire in the Mojave Desert, and modeling and monitoring of shrubland ecosystems. An overarching goal of the symposium was to make linkages between research and management

Soil and Water Conservation: An Annotated Bibliography

Soil and Water Conservation: An Annotated Bibliography highlights freely-available online resources covering various aspects of soil and water conservation, and is designed to be a resource for conservation students and practitioners. The thirteen chapters in the annotated bibliography are grouped into four sections, including History and Fundamentals, Conservation Practices, Conservation Implementation, and Careers. Types of cited resources include extension bulletins, USDA NRCS conservation practice standards, and other government reports and resources. Cited resources are generally concise, easily read, and meant for general audiences. Annotations and images are used to provide context for each resource. Many contributors made Soil and Water Conservation: An Annotated Bibliography possible through their assistance with technical edits, outline development, identifying resources, or writing annotations. Chapter authors are experts and practitioners of soil and water conservation, or students of soil and water conservation who worked under the supervision of the editor, Colby Moorberg. The annotated bibliography is used as the primary text for Kansas State University’s AGRON 635 – Soil and Water Conservation, which is taught by Moorberg.https://newprairiepress.org/ebooks/1030/thumbnail.jp

Pro-poor intervention strategies in irrigated agriculture in Asia: poverty in irrigated agriculture: issues and options: India

Irrigated farming / Poverty / Institutions / Irrigation programs / Performance evaluation / Irrigation management / Water distribution / Water rates / Cost recovery / India

Grassland management, soil biota and ecosystem services in sandy soils

Recent legislative restrictions on the use of fertilizers and irrigation, and a quest for sustainable farming systems have drawn renewed attention to the functioning of the soil and the ecosystem services it provides. Soil biota play an important role in the provision of these ecosystem services, which may be influenced by grassland management. The two objectives of this thesis were 1) to gain insight into the effect of different grassland management measures on soil biota in sandy soils; and 2) to explore the effect of grassland management on the ecosystem services provided by soil biota

An Empirical Study in the Sudan

Organisation und Management zur verbesserten Wassernutzung in der Landwirtschaft des Sudan - eine empirische Studie Der Sudan, das größte Land Afrikas, kann stellvertretend gesehen werden für die Probleme, die den afrikanischen Kontinent bewegen. An erster Stelle ist die Ernährungssicherung für eine steigende Bevölkerungszahl anzusehen. Bei Betrachtung der Dürre-Probleme dieser Region, die ihren Höhepunkt Mitte der 80er Jahre hatten, wird das Thema Bewässerung zunehmend zu einem Pfeiler, wenn es um die Verbesserung der Nahrungsmittelversorgung geht. Dieser Sub-Sektor spielt, historisch gesehen, eine wichtige Rolle für die Produktion von Nahrungsmitteln und landwirtschaftlichen Exportprodukten im Sudan. Jedoch gibt es zunehmende Anzeichen dafür, daß die Ausdehnung der Bewässerungssysteme generell in Konfrontation mit einer beschränkten Verfügbarkeit von Fremdwährung und Wasserressourcen stehen wird. Die erste Beschränkung ist abhängig von der Leistungsfähigkeit der sudanesischen Wirtschaft und die zweite von den Plänen anderer Länder. Da der erste Faktor seinen kritischen Punkt erreicht hat, ist es klar, dass Wasser, und nicht andere Ressourcen, die entscheidende Rolle bei der Entwicklung der Bewässerungssysteme spielen wird. Somit ist es notwendig, wenn die sudanesische Landwirtschaft entwickelt werden soll, das Management der Wassernutzung und die damit verbundenen organisatorischen Rahmenbedingungen zu vervollkommnen. Folglich war es die Hauptaufgabe der Studie, die Faktoren, die dem Ziel einer wirtschaftlichen Wassernutzung hinderlich sind, herauszuarbeiten. Die Studie teilt sich in zwei Abschnitte. Der erste Teil setzt sich mit den theoretischen Rahmenbedingungen relevanter Konzepte und Ansätze auseinander. Es werden die verschiedenen Aspekte, die Einfluß auf die Leistungsfähigkeit von Bewässerungssystemen haben, hervorgehoben. Dabei werden besonders Technologie und Umwelt betont. Zusätzlich werden die Bedeutungen und Bedingungen des Institutionellen Wandels diskutiert. Der zweite Teil der Studie widmet sich der Empirie, d.h. den Methoden und Ergebnissen der Feldforschung. Diese wurde in zwei Bewässerungs-Schemes durchgeführt: New Halfa Scheme in Ostsudan und Gendettu Scheme im Norden des Landes. Die Ergebnisse dieser Studie zeigen auf, daß ein umfassender Entwicklungsansatz alle natürlichen Ressourcen einbeziehen muß. Weiterhin dürfen auch die politischen Verhältnisse im Umfeld der Schemes nicht vernachlässigt werden. Das Ergebnis weist besonders auf die Frage hin, in welchem Ausmaß Partizipation anwendbar ist in den bürokratisch organisierten Bewässerungs-Systemen in Ländern mit ähnlichen Bedingungen. Es konnte festgestellt werden, daß auch die sozioökonomische Dimension beachtet werden muß, wenn die Effizienz der Bewässerung betrachtet wird, d.h. Produktivität und Rentabilität müssen in die Kalkulationen miteinbezogen werden. In diesem Zusammenhang ist es von von äußerster Wichtigkeit, der Modernisierung entsprechender Technologien und der Einbeziehung unterstützender Institutionen große Bedeutung zukommen zu lassen. Die zentrale Schlußfolgerung dieser Studie ist also, daß die Effizienz der Wassernutzung auch die gleichzeitige effiziente Nutzung anderer Ressourcen und Inputs, die von zuliefernden Institutionen zur Verfügung gestellt werden, erfordert. Zusätzlich ist anzumerken, daß das Nichtvorhandensein von Pächter-Partizipation und die Vorherrschaft der Interessen der Scheme-Verwaltung, als Repräsentanten des Staates, der Effizienz entgegenwirken, das heißt, daß sich die Effizienz der Wassernutzer und die des Staates diametral gegenüberstehen. Besonders hervorgehoben werden muß die mangelnde Kommunikation zwischen den verschiedenen Beteiligten der Schemes. Dieser Punkt führt die Aufmerksamkeit direkt zur Rolle der Bauernorganisationen als Verbindung zwischen den Wassernutzern und dem Scheme Management. Die Schlussfolgerung, die aus dieser Analyse gezogen werden kann, ist, daß die Bauernorganisationen ihre Aufgaben unabhängig wahrnehmen müssen. Schließlich betont die Studie, daß zur Erreichung der Ziele, die mit der Erhebung von Bewässerungsgebühren verbunden sind, gleichzeitig instutionelle Veränderungen erforderlich sind

Soil Erosion and Sustainable Land Management (SLM)

This Special Issue titled “Soil Erosion and Sustainable Land Management” presents 13 chapters organized into four main parts. The first part deals with assessment of soil erosion that covers historical sediment dating to understand past environmental impacts due to tillage; laboratory simulation to clarify the effect of soil surface microtopography; integrated field observation and the random forest machine learning algorithm to assess watershed-scale soil erosion assessment; and developing the sediment delivery distributed (SEDD) model for sub-watershed erosion risk prioritization. In Part II, the factors controlling soil erosion and vegetation degradation as influenced by topographic positions and climatic regions; long-term land use change; and improper implementation of land management measures are well dealt with. Part III presents different land management technologies that could reduce soil erosion at various spatial scales; improve land productivity of marginal lands with soil microbes; and reclaim degraded farmland using dredged reservoir sediments. The final part relates livelihood diversification to climate vulnerability as well as the coping strategy to the adverse impacts of soil erosion through sustainable land management implementation which opens prospects for policy formulation. The studies cover regions of Africa, Europe, North America and Asia, being dominantly conducted under the framework of international scientific collaborations through employing a range techniques and scales, from the laboratory to watershed scales. We believe those unique features of the book could attract the interest of the wider scientific community worldwide

Water-Related Technologies for Sustainable Agriculture in U.S. Arid/Semiarid Lands

A report by the Office of Technology Assessment (OTA) that "assesses existing and emerging water-related technologies for their ability to support long-term productivity of arid/semiarid agricultural plants and animals in the context of institutional factors, water supply/use relationships, and the characteristics of the renewable natural resource base on which agriculture depends" (p. iii)

Agricultural Development in Asia and Africa

This Open Access book explores the multifaceted nature of agricultural and rural development in Asia and examines the extent to which the Asian experience is being replicated in contemporary Africa. This volume compiles the works of top scholars who provided analyses and evidences from household-level surveys collected for many years in several parts of Asia and Africa. The most important finding presented in this book is that African agricultural development has evolved following the pathways of Asian agricultural development. The common pathways are borrowed technology from abroad and adaptive research in rice farming; secured property rights on natural resources; adoption of ICTs; investments in human capital, including training; and launching of the high-value agriculture. In both continents, agricultural development started in the crop sector, which had a strong tendency to induce the dynamic development of other sectors in rural areas