Das Projekt "B 3.1: Efficient water use of mixed cropping systems in watersheds of Northern Thailand highlands" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Kulturpflanzenwissenschaften (340), Fachgebiet Düngung und Bodenstoffhaushalt (340i) durchgeführt. Worldwide an important part of agricultural added value is produced under irrigation. By irrigation unproductive areas can be cultivated, additional harvests can be obtained or different crops can be planted. Since its introduction into Northern Thailand lychee has developed as one of the dominating cash crops. Lychee is produced in the hillside areas and has to be irrigated during the dry season, which is the main yield-forming period. Water therefore is mainly taken from sources or streams in the mountain forests. As nowadays all the available resources are being used do to increased production, a further increase in production can only be achieved by increasing the water use efficiency. In recent years, partial root-zone drying has become a well-established irrigation technique in wine growing areas. In a ten to fifteen days rhythm one part of the root system is irrigated while the other dries out and produces abscisic acid (ABA) a drought stress hormone. While the vegetative growth and thus labor for pruning is reduced, the generative growth remains widely unaffected. Thereby water-use efficiency can be increased by more than 40Prozent. In this sub-project the PRD-technique as well as other deficit irrigation strategies shall be applied in lychee and mango orchards and its effects on plant growth and yield shall be analyzed. Especially effects of this water-saving technology on the nutrient balance shall be considered, in order to develop an optimized fertigation strategy with respect to yield and fruit quality. As shown in preliminary studies, the nutrient supply is low in soils and fruit trees in Northern Thailand (e.g. phosphate) and even deficient for both micronutrients boron (B) and zinc (Zn). Additionally, non-adapted supply of nitrogen (mineralization, fertilization) can induce uneven flowering and fruit set. Therefore, improvement is necessary. For a better understanding of possible influence of low B and Zn supply on flowering and fruit set, mobility and retranslocation of both micronutrients shall be investigated for mango and lychee. Finally, the intended system of partial root-zone fertigation (PRF) shall guarantee an even flowering and a better yield formation under improved use of the limited resource water. As this modern technique, which requires a higher level of irrigation-technology, cannot be immediately spread among the farmers in the region, in a parallel approach potential users shall be integrated in a participative process for adaptation and development. Water transport and irrigation shall be considered, as both factors offer a tremendous potential for water saving. Local knowledge shall be integrated in the participatory process (supported by subproject A1.2, Participatory Research) in order to finally offer adapted technologies for application within PRF systems for the different conditions of farmers in the hillsides of Northern Thailand.
Das Projekt "SP 2.4 Precision irrigation and fertigation technology for improving water- and fertilizer-efficiency of North China Plain production systems" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Agrartechnik, Fachgebiet Agrartechnik in den Tropen und Subtropen durchgeführt. Water shortage has become a major limiting factor for agricultural production in the North China Plain. Inadequate irrigation practices are causing excessive evaporation and deep percolation losses. Apart from low water efficiency, this leads to leaching of nutrients and increasing pollution of ground water and down-stream aquifers. Therefore, objective of the subproject is to design an innovative mobile micro-irrigation system with site-specific water and fertilizer application based on plant growth modeling and real time soil moisture and plant status measurement. Water-, energy- and fertilizer efficiency of the irrigation system will be evaluated. Finally, the system will be adapted to the socio-economic conditions of the farmers in the North China Plain.
Das Projekt "B 3.2: Irrigation and fertigation strategies for water saving and optimum nutrient supply in subtropical fruit orchards utilising stress responses" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Institut für Kulturpflanzenwissenschaften (340), Fachgebiet Düngung und Bodenstoffhaushalt (340i) durchgeführt. Irrigation and fertigation are main management tools in fruit tree production. Due to the scarcity of water and its susceptibility to contamination with agrochemicals, the objective of subproject B3.2 is to reduce water and fertilizer application without reducing farmers benefits. Results from SFB-phase II indicate, that moderate levels of water and nutrient stress can be used to improve orchard productivity (eustress). (A) Irrigation: Deficit irrigation techniques, namely Partial Rootzone Drying (PRD) and Regulated Deficit Irrigation (RDI) have a big potential for water saving without reducing fruit yield and quality. (B) Fertigation: Zn and B stress effect flower induction, which has to be considered for improved orchard management. (C) Participatory field application: An adapted irrigation control unit was developed and indigenous knowledge on deficit irrigation was identified. In SFB-phase III, drought and nutrient stress phenomena and their interactions will be further investigated to develop innovative Irrigation and Fertigation Strategies (IFS) by a close interaction of on-station and participatory on-farm experiments. One of the objectives is the increase of Water Use Efficiency (WUE) and improvement of fruit quality by applying controlled water and nutrient stress but preventing stress related long-term damage (Topic A). On-station fruit trees will be exposed to spatial and temporal varying water and nutrient supply regimes. Stress response such as sap-flow, xylem pH, stomatal conductance and leaf water potential will be monitored. Optimum combination of stress response signals will be identified using sensor fusion methodology. Threshold values for eustress will be determined and validated in on-farm applications. A coequal objective is the development of a controlled water and fertilizer saving fertigation management system, guaranteeing high yields with less alternating fruit set and an improved fruit quality (Topic B). Fruit trees will be cultured in nutrient solutions with different Zn and B supply and at different temperatures to determine the critical Zn and B nutritional status for flower induction and the underlying phytohormonal regulation. It will be determined during which phenological phases drought stress and nutrient deficiency can be beneficial for flower induction, yield formation and fruit quality. In a participatory approach, IFS-strategies will be applied in on-farm trials at various locations to develop adapted IFS-recommendations jointly with the involved farmers. Telecommunication will be used to disseminate results to practical farming (Topic C).
Das Projekt "Untersuchung der Wirkung von Saeureablagerung durch Manipulation von Waldoekosystemen" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Institut für Bodenkunde und Waldernährung durchgeführt. Objective: To quantify the effects of adverse soil conditions caused by acid atmospheric deposition on forest ecosystems. General information: the research will be done at fives sites with different atmospheric and ecological conditions using soil manipulation, and collecting the same set of parameters. At each of the sites, plots will be established with a range of soil chemical conditions for tree growth in existing sites, by various methods: fertigation to arrive at optimal soil chemical conditions for tree growth (Netherlands; Denmark; sannarp, w Sweden; vindeln, n Sweden), liming and fertilization (Hoeglwald, BRD; Swedish sites), experimental acidification (Hoeglwald, BRD), and water- and nutrient removal (Solling, BRD). At each site, tree growth and nutrient cycling (including nutrient mineralization and immobilization) will be measured. There will be full data exchange so that each research group can apply its particular models to all sites, while specialized activities will be done at all sites by the partner best specialized for the job. An extension is foreseen to study the carbon balance of trees, and to quantify the effect of ambient and clean (filtered) air under various (adverse and improved) soil chemical condition pertaining to acid atmosphere by gas exchange studies using mobile equipment.
Das Projekt "Subarea specific irrigation system for pivot- and linear fertigation techniques (SMART Fertigation)" wird vom Umweltbundesamt gefördert und von HYDRO-AIR international irrigation systems GmbH durchgeführt.
Das Projekt "Fertigation und Baumstreifenbegruenung im integrierten Apfelanbau" wird vom Umweltbundesamt gefördert und von Universität Hannover, Institut für Obstbau und Baumschule durchgeführt. Intensive Apfelanlagen werden meistens in Streifenkultur betrieben: waehrend die Baumstreifen durch Herbizide unkrautfrei gehalten werden, bleiben die Fahrgassen dauerbegruent. Ein begruenter Baumstreifen im Agraroekosystem Apfelanlage wuerde dagegen den Vorstellungen des integrierten Apfelanbaus noch besser entsprechen. Der Einfuehrung der Baumstreifenbegruenung steht aber ein erhoehter Wasserverbrauch und die Naehrstoffkonkurrenz entgegen. Auf einer Parabraunerde aus Loess in der Hildesheimer Boerde wird untersucht, ob durch eine bedarfsangepasste duengende Tropfbewaesserung (Fertigation) die dauerhafte Begruenung der Baumstreifen ohne Beeintraechtigung der vegetativen und generativen Leistungsfaehigkeit der Apfelbaeume moeglich ist. Weiter werden Einfluesse auf aeussere und innere Fruchtqualitaetsmerkmale, einzelne bodenphysikalische Parameter und die Naehrstoffdynamik (vor allem Stickstoff) im Boden untersucht.
Das Projekt "Transfer of INNOvative techniques for sustainable WAter use in FERtigated crops (FERTINNOWA)" wird vom Umweltbundesamt gefördert und von Proefstation voor de Groenteteelt vzw durchgeführt.
Das Projekt "Bestimmung der Stickstoffauswirkung mit Hilfe der 15N-Methode" wird vom Umweltbundesamt gefördert und von Universität für Bodenkultur Wien, Institut für Hydraulik und landeskulturelle Wasserwirtschaft durchgeführt. Durch den Einsatz des stabilen 15N-Isotops konnten verschiedene Messgeraete zur Stickstoffanwaschung getestet und die Stickstoffbewegung exakt gemessen werden.
Das Projekt "Stickstoffumsetzungen und -verlagerungen im Boden in einer bewaesserten Obstanlage im Hinblick auf den Grundwasserschutz" wird vom Umweltbundesamt gefördert und von Universität für Bodenkultur Wien, Institut für Hydraulik und landeskulturelle Wasserwirtschaft durchgeführt. Die Arbeit beschaeftigt sich mit den Auswirkungen einer modifizierten Stickstoffapplikation auf die Stickstoffumsetzung, N-Verlagerungen bzw. N-Auswaschungen im Boden hinsichtlich eines sanierenden bzw. vorbeugenden Grundwasserschutzes. Es soll festgestellt werden, ob durch den Einsatz von Fertigation die Stickstoffmenge bei weitgehender Erhaltung des Ertragspotentials des Bodens soweit eingeschraenkt werden kann, dass auch in Zukunft qualitativ gutes und hygienisch einwandfreies Grundwasser zur Verfuegung stehen wird.
Düngung im Obstbau • Wurzelsystem • Nährstoffhaushalt Bedarf und Entzug • Mineralien • Makroelemente • Mikroelemente • Blattdüngung • Fertigation • Ausbringungstechnik Düngung Besonderheiten des Wurzelsystems perennierender vs. annueller Arten • lange Standzeit am selben Standort • hoher Nährstoffbedarf durch jährlichen Blattabwurf und Neuaustrieb • spezifischer Bedarf von Blüten, Früchten, Blättern u. Holz • hohe Leistungsfähigkeit des Wurzelsystems notwendig Düngung - Wurzelsystem Wurzelsystem von Obstgehölzen • Flaches Wurzelsystem (70% in 0 bis 30 cm Tiefe) • Fast 90% im 1 m Umkreis um Stamm Düngung - Wurzelsystem