Arid Location Research Articles

Sekem: A Remarkable Tale of Social Entrepreneurship with Critical Lessons for Policy (Innovations Case Discussion: Sekem)

fascinating tale illustrating the difficult path that faces a social entrepreneur who undertakes a major project that points to a path for improvement of the state of society. It concerns a dedicated and idealistic entrepreneur, Ibrahim Abouleish, who undertook to transform a strikingly arid location in the Egyptian desert, with the determination to make it bloom and yield valuable crops. Moreover, it was intended from the beginning that the project would prove to be long lived and selfsustaining financially. The heroic undertaking and its eventual success is an exciting tale, superior to fiction both because it describes actual achievement and also because it offers insights of value to other agronomists seeking to bring productivity to deserts of the world elsewhere. But, implicitly, there are also important lessons in the Sekem story for those crafting economic policy aimed at amelioration of the universal problem of poverty that besets even the most affluent economies of the world and continues to pervade the developing societies. My purpose in this short paper is to draw further attention to, and elaborate upon, the lessons for policy designers embedded in the Sekem case.

Breeding potential of durum wheat landraces from Jordan

A Jordanian durum wheat collection consisting of 132 landraces was evaluated in an arid and a semiarid location for 21 morphological and developmental traits. Phenotypic diversity indices (H') were calculated for traits, districts, and regions of collection. Average diversity for Jordan was 0.675 ± 0.05. The pattern of variation of individual traits varied among districts and among regions. Polymorphism was high for waxiness (H' = 0.95), lodging resistance (0.91), stem solidness (0.86), glume color (0.80), and fertility of the basal floret (0.80). However, H' estimates were relatively low for early growth vigor (0.49), seed color (0.44) and juvenile growth habit (0.19). A clinal pattern was observed for resistance to common bunt, Tillelia foetiila (H' = 0.73), stripe rust, Puccinia striiformis (H' = 0.74), and powdery mildew, Erysiphe graminis f.sp. tritici (H' = 0.63). The frequency of resistant entries increased from the xeric south to the mesic north. Average diversity for developmental traits (i.e., days to heading, days to maturity, and filling period) was significantly higher in the semiarid (H'= 0.847 ± 0.05) than in the arid (H'= 0.658 ± 0.12) location. A hierarchical analysis of variance indicated that significant differences for H' estimates existed among regions and among districts within regions of collection. Landraces and districts with high frequency of agronom-ically desirable traits have been identified.

Breeding potential of durum wheat landraces from Jordan I. Phenotypic diversity

A Jordanian durum wheat collection consisting of 132 landraces was evaluated in an arid and a semiarid location for 21 morphological and developmental traits. Phenotypic diversity indices (H) were calculated for traits, districts, and regions of collection. Average diversity for Jordan was 0.675 ± 0.05. The pattern of variation of individual traits varied among districts and among regions. Polymorphism was high for waxiness (H’= 0.95), lodging resistance (0.91), stem solidness (0.86), glume color (0.80), and fertility of the basal floret (0.80). However, H’ estimates were relatively low for early growth vigor (0.49), seed color (0.44) and juvenile growth habit (0.19). A clinal pattern was observed for resistance to common bunt, Tillelia foetiila (H’= 0.73), stripe rust, Puccinia striiformis (H’= 0.74), and powdery mildew, Erysiphe graminis f.sp. tritici (H’= 0.63). The frequency of resistant entries increased from the xeric south to the mesic north. Average diversity for developmental traits (i.e., days to heading, days to maturity, and filling period) was significantly higher in the semiarid (H= 0.847 ± 0.05) than in the arid (H= 0.658 ± 0.12) location. A hierarchical analysis of variance indicated that significant differences for H’ estimates existed among regions and among districts within regions of collection. Landraces and districts with high frequency of agronomically desirable traits have been identified.

Cameraria gaultheriella and C. lobatiella attracted in Canada to (E,Z)-8,10-tetradecadienal, the sex pheromone of the European C. ohridella

AbstractField trapping trials showed that Cameraria gaultheriella Walsingham and C. lobatiella Opler and Davis (Lepidoptera: Gracillariidae) were attracted in significant numbers in British Columbia, Canada, to sticky traps baited with 10 µg of (E,Z)-8,10-tetradecadienal (E8Z10-14Ald), the sex pheromone of the European horse chestnut leafminer, C. ohridella Deschka and Dimic. There was perfect specificity in captures at habitats located only about 8 km apart from each other: C. gaultheriella was captured exclusively at a humid habitat covered by the shrub salal, Gaultheria shallon Pursh (Ericaceae), whereas C. lobatiella was trapped at an arid location with Garry oak trees, Quercus garryana Dougl. (Fagaceae). Seasonal flight patterns of these two Canadian Cameraria species, as monitored by pheromone traps, indicated differences in their respective flight periods. The possibility of additional cryptic components in the respective pheromones of these three Cameraria species attracted to E8Z10-14Ald is discussed.

Application of sludge from urban wastewater treatment plants in road's embankments

While different kinds of compost have been tested for highway revegetation, sewage sludge has only been used for agricultural purposes. In this work, its application for helping vegetation establishment on roads embankments is studied. Testing areas measuring 4 × 5 m were constructed on a new highway embankment in an arid location. Several variables are analyzed: side slope (2); sludge dosage (4); vegetative species (4). Results are presented on growth, survival rate and germination of the plants; colonization of other species; cover crop for the plots; estimation of the erosion. The species planted manually showed satisfactory results although any variable was specially significant in this case. However, in relation to the species planted using hydroseeding, 2:1 side slope presented better results than 3:2 side slope. Using hydroseeding, the performance of different species was significantly different, thyme did not grow if sludge was not applied and the cover crop was higher in plots with 3:2 side slope than in plots with 2:1 side slope, essentially due to the presence of colonizing species. Finally, the costs of the proposed treatments are figured out, being concluded that, so much from the technical as the economic point of view, it is a viable proposal for sewage sludge management.

Chemical Composition of Pea Seeds as Related to Seed Yield under Arid and Semiarid Mediterranean Environments

AbstractLittle has been published on the chemical composition of pea (Pisum sativum L.) seeds and its relationship to seed yield. This study was conducted to investigate the relationships between seed protein, lipid, starch and sugars content of pea with seed yield under arid and semiarid Mediterranean environments. Twenty pea genotypes were grown at an arid (JUST) and semiarid (Maru) locations in northern Jordan. With the exception of glucose and fructose, the variation in protein, lipid, sucrose and starch was caused by environmental conditions. Pea grown at the semiarid location exhibited higher yield and the lower protein, glucose, fructose and sucrose contents than those grown at the arid location. Except for lipid and starch, high seed yields of genotypes were associated with low contents of protein and sugars, indicating that one‐sided selection for high seed yield tends to reduce the nutritional quality of pea seed.

Radiative cooling during the day: simulations and experiments on pigmented polyethylene cover foils

Pigmented foils can promote radiative cooling of an underlying object if they reflect most of the solar light and transmit a part of the thermal radiation in the atmospheric window in the infrared. In this paper we describe the optimization of optical properties, and simulations of thermal performance during the day for pigmented polyethylene foils. The tested pigment materials were ZnS, ZnSe, TiO 2, ZrO 2 and ZnO. It was found that only ZnS could promote cooling of a black body radiator in an insulated box at noon with the sun in zenith position. A 400 μm thick ZnS pigmented foil with a pigment volume fraction of 0.15 and a solar reflectance of 0.849 was tested in Tanzania. At noon the temperature was slightly above the ambient, and the heating power was approximately 7.2 Wm −2. However, this foil proved that cooling of a black surface could be obtained more than 19 hours per day in an arid location close to the equator.

Modelling and simulation of a solar absorption cooling system

A detailed numerical simulation model is developed for a commercially available solar absorption chiller. The model incorporates the performance data of a Yazaki-manufactured water-cooled system. We take into consideration the variation of the COP and cooling water temperature. Using a summer season's meteorological data for an arid location in the Sahara desert, the system performance is computed for different collector types, areas and storage volumes. The results show that an optimum storage volume/collector area ratio exists. Also a high solar fraction can be obtained with relatively small areas of collectors, even when the collectors are of the inexpensive type. The interesting feature was that the system operated at design load conditions with generator temperatures as low as 80°C owing to the fact that very low cooling water temperatures are available in the dry conditions of the Sahara. The study establishes the high potential of solar operated, water-cooled absorption coolers especially for arid conditions.