Chemical control and herbicide resistance of hairy fleabane [Conyza bonariensis (L.) Cronquist] in Jordan

Two field experiments were conducted to evaluate the effectiveness of 12 herbicides in controlling hairy fleabane [ Conyza bonariensis (L.) Cronquist] in a date palm orchard located in the central Jordan valley during the spring of 2017. Results showed that C. bonariensis resists paraquat (2.5, 5 and 7.5kgha -1 ), oxadiazon (5kgha -1 ) and oxyflourfen (3.3kgha -1 ) herbicides applied at normal or higher than the recommended rates. None of the three herbicides was significantly effective against the weed and treated plants continued growing normally similar to those of untreated control. Higher rates (10-fold of the recommended rates) of the same herbicides failed to control the weed. The effect of other tested herbicides on the weed was varied with bromoxynil plus MCPA (buctril ® M), 2,4-D- iso-octyl ester, glyphosate, glyphosate trimesium and triclopyr were most effective and completely controlled the weed at recommended rates of application. Testing paraquat, oxadiazon and oxyflourfen using the normal recommended and 10-fold higher rates on two populations of C. bonariensis grown from seeds of the date palm and al-Twal (another site in the Jordan Valley) weed populations and grown in pots under glasshouse conditions showed that Date palm population was resistant to the three herbicides at both application rates while al-Twal site population was highly susceptible and completely controlled at normal and high rates of the three herbicides. It is concluded that certain populations of C . bonariensis developed resistance to paraquat, oxadiazon and oxyflourfen but control of this weed was possible using other herbicides of different mechanism of action. Herbicide rotation or other nonchemical weed control methods have been suggested to prevent or reduce the buildup and spread of resistant populations of this weed species. These results represent the first report on herbicide resistance of C. bonariensis in Jordan.

A Late Pleistocene Wetland Setting in the Arid Jurf ed Darawish Region in Central Jordan

Current conditions in the southern Levant are hyperarid, and local communities rely on fossil subsurface water resources. The timing of more favourable wetter periods and also their spatial characteristics are not yet well constrained. To improve our understanding of past climate and environmental conditions in the deserts of the southern Levant, sedimentary sections including artefact-bearing beds from Jurf ed Darawish on the Central Jordanian Plateau were investigated using sedimentological and micropalaeontological analyses and OSL dating. Grain-size analysis and structures of the clayey-silty sediments show that they mainly represent reworked loess deposits. The OSL ages suggest that these fine-grained sediments were accumulated during Marine Isotope Stages (MIS) 5-3. Recorded ostracod valves (mostly Potamocypris, Ilyocypris and Pseudocandona), remains of aquatic and terrestrial gastropod shells, and charophyte gyrogonites and stem encrustations indicate that an in-stream wetland existed at the location of Jurf ed Darawish during MIS 5-4 which was replaced by a vegetated alluvial plain in MIS 3. The prevailing aggradational setting was replaced by an erosional setting sometime after 30 ka. Abundant artefacts, distributed over a vertical range of up to 40 cm in a bed covered by a sedimentary sequence of 12-m thickness, provide evidence for the presence of humans in the region during a relatively long period from ca. 85 to 65 ka. The reconstruction of an in-stream wetland at Jurf ed Darawish, and the presence of humans at the site and in other desert regions of the Jordanian Plateau, the Wadi Arava/Araba, and the Negev and the Nefud deserts, show that the regional climate in the late MIS 5 and MIS 4 was significantly wetter than today and provided favourable conditions for humans in the Southern Levant and the northwestern Arabian Peninsula.

Hemp! Thread, cloth and a calendar

Hemp cultivation and hempen cloth is the main theme of this paper. Iron Age textile fragments from the Southern Levant indicate that most textiles were made of some kind of plant fiber. Traditionally this region was regarded as linen territory, and indeed most textile finds were registered as such. The difference between linen and hemp is difficult to tell even with a regular microscope. But when using a scanning electron microscope, the difference becomes visible. This technique sheds new light on the use of bast fibers in the region. A piece of fabric from Tell Deir Alla in the Jordan Valley was the first item that could be registered as hempen cloth from the Southern Levant. The textile fragment was found amidst the loom weights of the loom on which it was woven, which raises new questions. Was the textile made of local hemp grown in the Jordan Valley? To answer this question, the cultivation of hemp will be discussed in relation to soil and climatic conditions of the central Jordan Valley. To investigate if growing hemp would fit into the farmers year course a ‘Deir Alla Agricultural Calendar’ was designed, based on the Gezer Calendar, a Hebrew inscription on limestone dated to ca. 925 BCE. Finally stalks of fiber hemp and examples of hempen thread and fabric will reveal how the material looks and… feels.

Carbon stock changes through dryland rehabilitation: a case study from central Jordan’s agro-pastures

<p>Land cover, productivity and carbon stocks are among the widely acknowledged indicators of the land’s degradation and development status. The indicators’ assess-ability, however, differs across global ecosystems and location. Despite the complexity of carbon stocks, soil carbon in particular is receiving increasing attention for its potential in both climate change mitigation and economic growth in developing carbon markets. <br>The degraded drylands of Jordan have been targeted by multiple investment programs to rehabilitate their arid agro-pastures, including through the application of mechanized micro-water harvesting structures combined with the plantation of native shrub seedlings. Whilst both local and remote land cover and biomass change monitoring indicate variable rehabilitation success, the related carbon stock changes remain largely under-investigated and unclear.<br>An international research consortium designed and implemented a study to investigate the actual and potential future carbon stocks per ecosystem status at an agro-pastoral research site located in central Jordan’s ‘Badia’, considering both conventionally managed (degraded) and rehabilitated lands. Field experiments conducted by scientists and  local and former tribal community collaborators were combined with carbon modeling using RothC. This enabled the development of multiple scenarios considering both natural and enhanced, or human induced, processes; for example, through landscape modification (mechanized micro-water harvesting), vegetation plantation as well as optional soil amendment through biosolids. Preliminary results suggest that the implementation of water harvesting structures leads to a pronounced increase in soil carbon sequestration when compared to baseline conditions of between 15% and 45% over a 5 year period , with work ongoing to quantify the uncertainties around these results. The selected rehabilitation scenarios match the criteria for vast potential upscaling across global drylands. The study outcomes will eventually support a comprehensive ecosystem services valuation approach with (soil) carbon as an integral factor and moving towards reversing degradation and crediting the dry ecosystem’s values beyond their marginal agricultural services.</p>

The Hydrogeochemical Stratigraphy of Brines and Its Implications on Water Management in the Central Jordan-Dead Sea Rift Valley, Israel

The exploratory borehole Megiddo-Jezre’el 1 (MJ1) was drilled in Israel, in the Bet She’an Valley which branches out from the Central Jordan Rift. It reached the depth of 5060 m and bottomed within the Upper Triassic Mohilla Fm. Following the increase of groundwater exploitation, the Cl- concentrations increased and ionic ratios changed indicating inflow of Ca2+-Cl- brines, the origins of which were hitherto unknown. Data from the new MJ1 borehole revealed that rock porosities decrease with depth. Lowermost values of about 3% were interpreted from logs in Lower Jurassic and Triassic strata. The highest shut-in pressures were measured in the Upper Jurassic sequence raising the water much higher than the ground surface. Along the drilled section, there is a continuous downward increase in Cl- concentrations in the range of 12-186 g Cl-/l and a very clear stratification of brines. Data from the MJ1 borehole and from other exploration wells indicate that in the subsurface of the area, there are two definite source brines: Triassic brine and the Late Tertiary (so-called) Rift brine. Brines encountered in Jurassic and Cretaceous beds represent ancient mixtures of the two source brines involving various water-rock chemical transformations. Evidence of very high pressures in deep boreholes Devora 2A, Rosh Pinna 1, and MJ1 revealed the existence of a mechanism in which the deep brines are “piston-driven” upwards and possibly also laterally. The ongoing salinization of groundwater in the area is due to the inflow of the Late Tertiary Ca2+-Cl- Rift brines and not that of the Jurassic or Triassic brines. The hydrogeological and hydrochemical data from borehole MJ1 is of major importance for the management of groundwater resources in the Central Jordan Rift Valley and in the adjacent geologically connected areas.