Winter versus spring sowing of rain-fed safflower in a semi-arid, high-elevation Mediterranean environment

2007 ◽  
Vol 26 (3) ◽  
pp. 249-256 ◽  
Author(s):  
S.K. Yau
Keyword(s):  
High Elevation ◽  
Mediterranean Environment ◽  
Spring Sowing ◽  
Semi Arid

scholarly journals Effects of maquis clearing on the properties of the soil and on the near-surface hydrological processes in a semi-arid Mediterranean environment

2014 ◽  
Vol 45 (4) ◽  
pp. 176 ◽  
Author(s):  
Mario Pirastru ◽  
Marcello Niedda ◽  
Mirko Castellini
Keyword(s):  
Land Use ◽  
Hydraulic Properties ◽  
Water Infiltration ◽  
Hydrological Processes ◽  
Soil Water Storage ◽  
Water Yield ◽  
Mediterranean Environment ◽  
Canopy Interception ◽  
Near Surface ◽  
Semi Arid

Many hillslopes covered with maquis in the semi-arid Mediterranean environment have been cleared in recent decades. There is little information on what effect this has on the hydrology of the soil. We compared the hydraulic properties of the soil and the subsurface hydrological dynamics on two adjacent sites on a hillslope. One site was covered with maquis, the other with grass. The grass started to grow some 10 years ago, after the maquis had been cleared and the soil had been ploughed. Our study found that the hydraulic properties and the hydrological dynamics of the maquis and the grassed soil differed greatly. The grassed soil had less organic matter and higher apparent density than did the soil covered in maquis. Moreover, the maquis soil retained more water than the grassed soil in the tension range from saturation to 50 cm of water. Infiltration tests performed in summer and in winter indicated that the field saturated hydraulic conductivity (K<sub>fs</sub>) of the maquis soil was higher than that of the grassy soil. However the data showed that the K<sub>fs</sub> of the two soils changed with the season. In the maquis soil the K<sub>fs</sub> increased from summer to winter. This was assumed to be due to water flowing more efficiently through wet soil. By contrast, in the grassy soil the K<sub>fs</sub> decreased from summer to winter. This was because the desiccation cracks closed in the wet soil. As result, the influence of the land use change was clear from the K<sub>fs</sub> measurements in winter, but less so from those in the summer. Changes in land use altered the dynamics of the infiltration, subsurface drainage and soil water storage of the soil. The maquis soil profile never saturated completely, and only short-lived, event based perched water tables were observed. By contrast, soil saturation and a shallow water table were observed in the grass covered site throughout the wet season. The differences were assumed to be due to the high canopy interception of the maquis cover, and to the macropores in the grassed soil being destroyed after the maquis had been cleared and the soil ploughed. The results of this work are helpful for predicting the changes in the hydraulic properties of the soil and in the near-surface hydrological processes in similar Mediterranean environments where the natural vegetation has been cleared. These changes must be taken into consideration when developing rainfall-runoff models for flood forecasting and water yield evaluation.

scholarly journals Post-LGM glacial retreat drives aggradation in the interiors of the Kashmir Himalaya

2021 ◽  
Author(s):  
Saptarshi Dey ◽  
Naveen Chauhan ◽  
Anushka Vashistha ◽  
Vikrant Jain
Keyword(s):  
Climate Change ◽  
Foreland Basin ◽  
High Elevation ◽  
Sediment Supply ◽  
Kashmir Himalaya ◽  
Glacial Retreat ◽  
Valley Fill ◽  
Mean Grain Size ◽  
Exposure Ages ◽  
Semi Arid

Understanding the response of glaciated catchments to climate change is fundamental for assessing sediment transport from the high-elevation, semi-arid to arid sectors in the Himalaya to the foreland basin. The fluvioglacial sediments stored in the semi-arid Padder valley in the Kashmir Himalaya record valley aggradation during ~19-11 ka. We relate the valley aggradation to increased sediment supply from the deglaciated catchment during the glacial-to-interglacial phase transition. Previously-published bedrock-exposure ages in the upper Chenab valley suggest ~180 km retreat of the valley glacier during ~20-15 ka. Increasing roundness of sand-grains and reducing mean grain-size from the bottom to the top of the valley-fill sequence hint about increasing fluvial transport with time and corroborate with the glacial retreat history. Our result also correlates well with late Pleistocene-early Holocene sediment aggradation observed across most Western Himalayan valleys. It highlights the spatiotemporal synchronicity of sediment transfer from the Himalayas triggered by climate change.

YIELD AND QUALITY OF RED STIGMAS FROM DIFFERENT SAFFRON STRAINS AT CONTRASTING MEDITERRANEAN SITES

2006 ◽  
Vol 42 (4) ◽  
pp. 399-409 ◽  
Author(s):  
S. K. YAU ◽  
M. NIMAH ◽  
I. TOUFEILI
Keyword(s):  
Field Experiments ◽  
High Elevation ◽  
Crocus Sativus ◽  
Coastal Site ◽  
Yield And Quality ◽  
High Elevation Site ◽  
Colour Strength ◽  
Semi Arid

Three different saffron strains (Crocus sativus, C. sativus var. ‘cashmerianus’ and C. cartwrightianus) were tested for two years in field experiments to study their red stigma yield and quality. The experiments were performed at a high-elevation (rainfed or irrigated) site and a coastal site in Lebanon. On average, the two C. sativus strains gave more flowers and stigma yield than C. cartwrightianus. The former was more productive in the more favourable environments, especially at the warmer coastal site, than the latter. C. sativus ‘cashmerianus’, which yielded better at the coastal site in 2004 and gave a stronger colour strength and aroma, appeared to be the better choice for the area. Mean yield at the coastal site was twice that at the non-irrigated high-elevation site. On average, saffron produced at the coastal site had more colouring strength and bitterness than that produced at the high-elevation site. Nevertheless, viable commercial saffron production may still be possible in the semi-arid, high-elevation Bekaa Valley if irrigation can be provided.

Variations in the Volatile Compounds of a Fennel (Foeniculum VulgareMill.) Variety Grown in a Semi-Arid Mediterranean Environment

2005 ◽  
Vol 8 (3) ◽  
pp. 275-288 ◽  
Author(s):  
Alessandra Carrubba ◽  
Raffaele la Torre ◽  
Antonella Di Prima ◽  
Filippo Saiano ◽  
Giuseppe Alonzo
Keyword(s):  
Volatile Compounds ◽  
Mediterranean Environment ◽  
Semi Arid

scholarly journals Post-LGM glacial retreat and Early Holocene monsoon intensification drives aggradation in the interiors of the Kashmir Himalaya

2021 ◽  
Author(s):  
Saptarshi Dey ◽  
Naveen Chauhan ◽  
Pritha Chakravarti ◽  
Anushka Vashistha ◽  
Vikrant Jain
Keyword(s):  
High Elevation ◽  
Sediment Supply ◽  
Early Holocene ◽  
Kashmir Himalaya ◽  
Glacial Retreat ◽  
Valley Fill ◽  
Initial Stage ◽  
Exposure Ages ◽  
The Himalaya ◽  
Semi Arid

Understanding the response of glaciated catchments to climate change is crucial for assessing sediment transport from the high-elevation, semi-arid sectors in the Himalaya. The fluvioglacial sediments stored in the semi-arid Padder valley in the Kashmir Himalaya record valley aggradation during ~20 -10 ka. We relate the initial stage of valley aggradation to increased sediment supply from the deglaciated catchment during the glacial-to-interglacial phase transition. Previously-published bedrock-exposure ages in the upper Chenab River valley suggest ~180 km retreat of the valley glacier during ~20 - 15 ka. Increasing roundness of sand-grains and reducing mean grain-size from the bottom to the top of the valley-fill sequence hint about increasing fluvial transport with time and corroborate with the glacial retreat history. The later stages of aggradation can be attributed to strong monsoon during the early Holocene. Especially, the hillslope debris that drapes the fluvioglacial sediment archive may have resulted from the early Holocene monsoon maximum. We observe a net degradation of the valley-fill in the Holocene reflecting the weakening of summer monsoon or reduced input from the glaciers. Our study highlights the coupled effect of deglaciation and monsoon intensification in sediment transfer from the high-elevation sectors of the Himalaya.

scholarly journals Influence of climate variability on water partitioning and effective energy and mass transfer (EEMT) in a semi-arid critical zone

2015 ◽  
Vol 12 (8) ◽  
pp. 7933-7969 ◽  
Author(s):  
X. Zapata-Rios ◽  
P. D. Brooks ◽  
P. A. Troch ◽  
J. McIntosh ◽  
C. Rasmussen
Keyword(s):  
Climate Variability ◽  
Water Availability ◽  
Snow Water Equivalent ◽  
High Elevation ◽  
Critical Zone ◽  
Effective Energy ◽  
Near Surface ◽  
Basin Scale ◽  
Water Partitioning ◽  
Semi Arid

Abstract. The Critical Zone (CZ) is the heterogeneous, near-surface layer of the planet that regulates life-sustaining resources. Previous research has demonstrated that a quantification of the influxes of effective energy and mass (EEMT) to the CZ can predict its structure and function. In this study, we quantify how climate variability in the last three decades (1984–2012) has affected water availability and the temporal trends in EEMT. This study takes place in the 1200 km2 upper Jemez River Basin in northern New Mexico. The analysis of climate, water availability, and EEMT was based on records from two high elevation SNOTEL stations, PRISM data, catchment scale discharge, and satellite derived net primary productivity (MODIS). Records from the two SNOTEL stations showed clear increasing trends in winter and annual temperatures (+1.0–1.3 °C decade−1; +1.2–1.4 °C decade−1, respectively), decreasing trends in winter and annual precipitation (−41.6–51.4 mm decade−1; −69.8–73.2 mm decade−1, respectively) and maximum Snow Water Equivalent (SWE; −33.1–34.7 mm decade−1). The water partitioning fluxes at the basin scale showed statistically significant decreasing trends in precipitation (−61.7 mm decade−1), discharge (−17.6 mm decade−1) and vaporization (−45.7 mm decade−1). Similarly Q50, an indicator of snowmelt timing, is occurring 4.3 days decade−1 earlier. Results from this study indicated a decreasing trend in water availability, a reduction in forest productivity (4 g C m−2 per 10 mm of reduction in Precipitation) and EEMT (1.2–1.3 MJ m2 decade−1). These changes in EEMT point towards a hotter, drier and less productive ecosystem which may alter critical zone processes in high elevation semi-arid systems.

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