BEGIN:VCALENDAR VERSION:2.0 PRODID:-//www.bayceer.uni-bayreuth.de//NONSGML kigkonsult.se iCalcreator 2.41.92// CALSCALE:GREGORIAN METHOD:PUBLISH UID:38343266-3335-4632-b233-363163646132 X-WR-CALNAME:BayCMS-Export X-WR-CALDESC:This is a calendar exported from BayCMS X-WR-TIMEZONE:Europe/Berlin BEGIN:VTIMEZONE TZID:Europe/Berlin TZUNTIL:20061029T010000Z BEGIN:STANDARD TZNAME:CET DTSTART:20041031T030000 TZOFFSETFROM:+0200 TZOFFSETTO:+0100 RDATE:20051030T030000 END:STANDARD BEGIN:DAYLIGHT TZNAME:CEST DTSTART:20040328T020000 TZOFFSETFROM:+0100 TZOFFSETTO:+0200 RDATE:20050327T020000 RDATE:20060326T020000 END:DAYLIGHT END:VTIMEZONE BEGIN:VEVENT UID:www.bayceer.uni-bayreuth.de-bayceer-t53285id DTSTAMP:20260804T093945Z DESCRIPTION:Little is known about the causes of the apparently sustainable productivity of ancient irrigation agriculture in the mountains of the Ara bian peninsula. To fill this gap of knowledge\, interdisciplinary research is conducted since 1999 in two desert oases of northern Oman with their h undreds of tiny multi-cropped terraces. The process-oriented agroecosystem s approach chosen hypothesized effective nutrient cycling\, water manageme nt with adequate leaching\, highly buffered springs and a wide intra-speci fic plant biodiversity to be likely causes for the oases² existence over m illennia. Spatially strongly variable\, but overall large annual nutrient inputs to crops (up to 1400 kg N\, 210 kg P and 1400 kg K ha-1) seem to ca use large surpluses in partial field and oasis balances making the studied oases important sinks for water and nutrients at the landscape level. On the clay-rich man-made terrace soils with mean CO2-evolution rates of 45.5 mg C m−\;2 h−\;1 for landraces of wheat (Triticum sp.) and 97.5 mg C m−\;2 h−\;1 for alfalfa (Medicago sativa L.) the latter sh owed at an average annual total dry matter production of 22 t ha-1 an biol ogical N2-fixation of 480 kg ha-1 thereby contributing substantially to th e positive nutrient balances of the cropland. Partial balances of palm gro ves (Phoenix dactylifera L.) were with 313 kg N\, 43 kg P and 191 kg K ha- 1 (on 8.8 ha) and 83 kg N\, 14 kg P and 85 kg K ha-1 (on 3.6 ha) remarkabl y different in both oases. This was mainly due to the recycling of nutrien ts in human faeces from the artificially high population in the first oasi s living largely on imported food. During irrigation cycles of 6-9 days vo lumetric water contents in the terrace soils ranged from 30-13%. A tracer experiment revealed that 52-56% of the irrigation water was stored in the upper 0.4 m of the soil. The rest of the water moved further down the prof ile\, thereby providing the necessary drainage to avoid the build-up of to xic salt concentrations. Due to differences in pore size\, plant-available water in the topsoil amounted to 18.7% compared to 13% and 13.5% at 0.25 and 0.60 m depth\, respectively. The aggregate structure in the upper 1.0 m of the profile is likely preserved by concentrations of calcium carbonat e (CaCO3) from 379-434 mg kg-1 and Corg from 157-368 mg kg-1 soil. These d ata indicate that the sustainability of this irrigated landuse system is p artly due to the high quality of its irrigation water\, the elaborate terr ace structure and an irrigation scheme that allows a drainage of 5-10% of the applied water. Morphological and molecular genetic analyses of wheat b ut also of banana (Musa sp.) in combination with first results of pollen a nalyses of a 20 m deep soil profile not only confirm the assumed large gen etic diversity in some of these oasis systems but also provide evidence fo r the oases² role as refugia of ancient germplasm likely traded in the reg ion many centuries ago. DTSTART;TZID=Europe/Berlin:20050209T171500 DTEND;TZID=Europe/Berlin:20050209T235959 LOCATION:H6 SUMMARY:Prof. Dr. Andres Buerkert\, Lehrstuhl für Ökologischen Pflanzenbau und Agrarökosystemforschung\, Institut für Nutzpflanzenkunde\, Universität Kassel: Agrarökologie\, Nährstoffkreislauf\, Bewässerungsmanagement und p flanzengenetische Diversität in traditionellen Gebirgsoasen des N-Oman TRANSP:TRANSPARENT END:VEVENT END:VCALENDAR