1,721,062 research outputs found
Water Harvesting for Olive (Olea europaea L.) Trees in a Marginal Dry Area of Northwestern Syria
No full textOlive production in marginal dry areas requires careful soil, water, and nutrient management. Farmers in the Khanasser Valley, Syria, developed their own water-harvesting technique by combining V-shaped bunds with up- and down-slope tillage furrows after examination of the semi-circular structures in a no-till water harvesting research site. The farmers cooperated with the researchers to investigate the effects of their new water harvesting technique in this dry environment (220 mm annual rainfall). Soil moisture content was monitored weekly during the first half of 2004. A control treatment without water harvesting structures was also monitored. Throughout the rainy season, soil moisture content in the rootzone of the trees with water harvesting structures was 4 to 15% higher than in the control. Almost all water gained by water harvesting was stored in the layers below 40-cm depth. This study showed that little labor
investments by farmers can provide critical extra water needs to olive trees in dry, sloping lands
Effect of water harvesting on growth of young olive trees in degraded Syrian dryland
No full textOlive (Olea europaea L.) is a drought-tolerant tree which is usually grown in areas with a Mediterranean climate that receive >350 mm of annual rainfall. However, olive growing in Syria has recently expanded into drier areas (200–300 mm annual rainfall) where irrigation resources are limited. This study, carried out between November 2002 and October 2005, aimed to investigate the response of a little known Syrian drought-tolerant olive variety (Qaisi) to water harvesting and limited summer irrigation (200 l per tree) in an arid area (average annual rainfall of 210 mm) with Mediterranean climate in Syria. Soil moisture and growth of four-year-old trees were monitored regularly. Olive leaves were sampled at different stages to determine water content, specific mass, and N content. Stomatal conductance was also measured in 2005. Our results showed that water harvesting and summer irrigation improved soil moisture content, leaf water content (up to 36% higher in Sep. 2003), leaf N content (up to 45% higher in Aug. 2003), leaf stomatal conductance (up to 55% higher in Apr. 2005), and relative trunk growth rate. Water harvesting was most successful in wet years, although the water storage capacity was not enough to retain all harvested water. This study indicated that it is possible to grow drought-tolerant olive varieties in arid areas under little or no irrigation, but proper water and nutrient management should be considered for sustainable growth
GPS/GIS-integrated approach to the assessment of current soil erosion by water – experiences from Mediterranean NW-Syria
No full textThe assessment of site-specific soil erosion and the detection of its causes are preconditions for the implementation of adapted land use and land management practices. “Soil erosion damage mapping”, a well-tried erosion assessment method, was updated and improved by the integration of GPS and GIS. The method – developed in co-operation between the University of Bonn and ICARDA1 in Aleppo – proved to be helpful in acquiring rapid and detailed information about the current erosion problems. Causal relationships of relief parameters, soil characteristics, land use, vegetation cover and management practices to soil erosion can be detected and analyzed statistically by the use of this method. Based on the findings, recommendations for effective soil conservation measures can be given to achieve sustainable land management
Water-harvesting designs for fruit tree production in dry environments
No full textWater scarcity and increasing demand coupled with climate change require maximizing the use of available resources. Water harvesting (WH) systems are currently being used in many areas to sustain crops and increase water productivity. This study investigated the effect of three treatments (S15: 50-m(2) catchment area with 15% slope, S8: 50-m(2) catchment area with 8% slope, and L8: 70-m(2) catchment area with 8% slope) on the amount of water harvested in tree basin for young olive (Olea europaea L.) trees from November 2002 to July 2003. Soil moisture was monitored weekly during the rainy season and bi-weekly afterwards. To determine moisture changes in the catchment and target areas and amount of water harvested (in liters) for each tree, volumetric soil moisture content was measured at three or four points along the slope using a neutron probe down to a maximum depth of 120 cm, as soil depth allowed. WH structures increased soil moisture content in the rootzone compared to the catchment area. The rainfall threshold for runoff generation was less than 15 mm. Land slope was more important than micro catchment size for increasing the amount of water harvested. Compared to the 8% slope, the 15% slope resulted in larger harvested amounts for small storms, but the two were comparable when storms were large. The large micro-catchment size resulted in higher amounts of harvested water only in the presence of storms greater than 26 mm. After adding the amounts lost by evapotranspiration, the net amount of water harvested in the tree basin of each tree for the 2002-2003 rainy season reached 722 and 6881 (or 361 and 344mm) for treatments S15 and S8, respectively. Deeper soil profiles (i.e., >90 cm) were important to ensure longer storage periods. By early July, soil moisture content in the tree basin for treatments S15, L8 and S8 was still higher by 38, 13, and 5% respectively, than the levels recorded at the onset of the experiment. WH increased soil moisture content during the spring and early summer, a critical period for olive production. 2015 Elsevier B.V. All rights reserved
Water-Saving Techniques Practiced by Olive Growers in Dry Areas
No full textDuring the last two decades, olive production in Syria has expanded to less favorable marginal dry areas, where water is the most important limiting factor. Farmers in these areas have been applying special management practices in order to improve the productivity of their trees. In this paper, we describe some methods used by olive growers in Syria to cope with water scarcity and improve water-use efficiency in their groves. During the winter rainfall season, some farmers construct rainwater-harvesting catchments to increase soil moisture content in the root zone. The application of calcareous soil or stones as mulch under the canopy is another common practice in orchards characterized by red heavy soils that crack in summer. Special attention is given to a “subsurface insert irrigation system”, which reduces surface evaporation during the hot summer months
Microcatchment Water Harvesting for Olive Production in Water-scarce Environments
No full textSince time immemorial, people in dry environments have harvested water from rainfall for drinking, washing, livestock watering, and crop production. Motorized drilling equipment and pumps, as well as government-controlled dams, reservoirs, and pipelines, have greatly replaced this sustainable practice. Still, the establishment of small earthen
dikes, in a v-shape or semi-circle just down-slope of the tree, allow the harvesting of a critical water supplement for olive production in water-scarce environments. To provide recommendations for the development of farmer-based micro catchment water-harvesting systems, research was conducted in a recently established (1999), untilled olive orchard on the limestone hill slopes of Khanasser Valley, Syria. Long-term average winter rainfall in the valley is low (210 mm), but events that produce runoff on these stony slopes occur regularly. Small and large micro catchments (50 and 70 m2) were established on 8% slopes (S8 and L8) and 50-m2 catchments on 15% slopes (S15). Soil moisture measurements were taken with a neutron probe in the tree basin and in the catchment area every week during the rain season. The average amount of water harvested during the wet 2002/03 season (302 mm) was 121 L for L8, 140 L for S15, and 150 L for S8. The benefits of water harvesting for these young trees were reduced by the limited depths of the soil profile (45-120 cm). The research activities and discussions with olive growers in the valley have motivated a number of farmers to apply water-harvesting techniques in both tilled and untilled orchards on the slopes
How the soil moves upward in the olive orchards of NW Syria: sustainability analysis of a local innovation
No full textThis paper analyses a local innovation in response to intense soil degradation in olive orchards of north-west Syria. Farmers developed a practice consisting of quarrying red clayey soil in valley bottoms and applying this soil to hillslope olive orchards with heavily degraded calcareous soils. A biophysical, economic and social analysis of the practice of soil application identified the opportunities and risks of this innovative soil management technique. On the basis of a pairwise comparison of nine adjacent treated and nontreated orchard plots, soil applications were found to increase soil depth by 36%, soil water availability by 28% and total available soil nutrients: potassium (+45%), nitrogen (+12%) and phosphorus (+6%). Olive yield increased by about 40%. A cost–benefit analysis found this practice to be economically viable within a large geographical area, and farmers scored the practice higher than alternative methods. A socio-economic analysis revealed its widespread adoption among different farmer types. The positive results of soil applications at the farm level explain its fast adoption. However, potential risks – including the further depletion of soil resources and the transfer of soil-borne diseases – limit the long-term sustainability of this locally developed practice.sponsorship: The authors wish to thank ICARDA and its staff for logistic support, scientific advice and soil sample analyses; Nadia Salem for assistance during the field work and all farmers in Afrin district for their willingness to participate. We acknowledge the valuable assistance of Ward Colen and Eline Vanuytrecht and the financial support from VLIR-UOS and Research Foundation Flanders (FWO). We are also grateful to the reviewers and to Artemio Cerda for their valuable comments and suggestions that greatly improved the article. (VLIR-UOS, Research Foundation Flanders (FWO))status: Publishe
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Growing olives and other tree species in marginal dry environments
No full textOlives have been grown in the Mediterranean areas for over five thousand years and yet there is renewed interest in these and other tree crops for the marginal areas of the dry lands. The need to increase water-use efficiency and to diversify income generation and household food security of the rural people are the main driving forces behind this trend.
The livelihoods of the rural poor are increasingly threatened by land degradation, climate changes, and liberalization of trade markets that lower the competitiveness of products from marginal areas. There is a need to develop more options and higher-quality products in order to compete both nationally and
internationally. For the harsh environments of the dry lands, there is a need for robust crops that can endure extreme droughts and temperature fluctuations along with soils of low fertility.
Thus, this book is a timely addition to the literature on the potential for marginal dry areas. Although focusing mainly on olives, the reader can find information on other tree crops such as pistachio, fig, almond, pomegranate, cactus pear, jojoba, grape, and mulberry
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