Towards mapping the extent of irrigation in the last century : time series of irrigated area per country

A data set of annual values of area equipped for irrigation for all 236 countries in the world during the time period 1900 - 2003 was generated. The basis for this data product was information available through various online data bases and from other published materials. The complete time series were then constructed around the reported data applying six statistical methods. The methods are discussed in terms of reliability and data uncertainties. The total area equipped for irrigation in the world in 1900 was 53.2 million hectares. Irrigation was mainly practiced in all the arid regions of the globe and in paddy rice areas of South and East Asia. In some temperate countries in Western Europe irrigation was practiced widely on pastures and meadows. The time series suggest a modest rate of increase of irrigated areas in the first half of the 20th century followed by a more dynamic development in the second half. The turn of the century is characterized by an overall consolidating trend resulting at a total of 285.8 million hectares in 2003. The major contributing countries have changed little throughout the century. This data product is regarded as a preliminary result toward an ongoing effort to develop a detailed data set and map of areas equipped for irrigation in the world over the 20th century using sub-national statistics and historical irrigation maps

Energiefruchtfolgen für D-Südstandorte - Entwicklung und Optimierung von standortangepassten Anbausystemen für Energiepflanzenim Fruchtfolgeregime auf D-Südstandorten

Das Landesamt für Umwelt, Landwirtschaft und Geologie untersuchte auf einem D-Südstandort in der Dübener Heide acht verschiedene Fruchtfolgen mit Energiepflanzen zur Biogasproduktion. Untersucht wurde die Ertrags- und Biogasleistung. Für die Region wird empfohlen, den Anbau in fünfgliedrigen Fruchtfolgen vorzunehmen. Als ertragsstarke und ertragsstabile Energiepflanzen haben sich dabei Energiemais, Sudangras, Zuckerhirse und Kartoffeln bewährt. Sie sollten zu 30 bis maximal 60 % in der Fruchtfolge berücksichtigt werden. Von ökologischem (Humushaushalt) und ökonomischem Vorteil ist dabei der Aufbau von Fruchtfolgesystemen, die sowohl leistungsstarke Energiepflanzen als auch Nahrungspflanzen enthalten. Die leistungsfähigsten Fruchtfolgevarianten erreichen kumulative Trockenmasseerträge von 370 bis zu 430 dt TM/ha. Theoretische Methanleistungen von insgesamt 12.000 m³ Methan/ha sind möglich

The MAVA Approach

The broadening use of multimedia documents and the need to apply them to the field of higher education increase the demands a multimedia document system has to be tailored to. Simplifying the production and presentation of multimedia documents in a user-friendly way is a precondition for the advancement of multimedia in higher education. Further requirements to a multimedia system should be reusability and retrievability of documents, platform independence and an extensibility which allows to adapt the system to application specific needs. Particularly in the field of education multimedia documents should be more than view-only animations and allow an active appropriation of knowledge by offering interactive functionality. Another property useful for an application of multimedia documents in higher education is database connectivity. The multimedial document system MAVA ("Multimedia Document Versatile Architecture") meets these demands by using an accordant meta-document model as well as highly compatible internet standards like Java and XML. A MAVA user does not need programming knowledge at all since the system contains an editor which allows editing a document by means of a graphic user interface. MAVA documents can be displayed with minimal requirements at any time. Required media items are loaded dynamically prior to the presentation. Due to open interfaces the MAVA system can be extended by additionally required application specific components. MAVA was implemented and tested in a project conducted by the Institute of Parallel and Distributed High-Performance Systems (IPVR) of the University of Stuttgart in co-operation with the Library of the University of Stuttgart. The project was funded by the German Research Foundation (DFG) and has a successor project which aims to design and implement new extensions and to integrate MAVA into the libraries fulltext system OPUS (Online Publications of the University of Stuttgart)