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Universität Hamburg (2013)

Evaluation of the land resources for agricultural development - case study : El-Hammam Canal and its extension, NW Coast of Egypt

Sayed, Ahmed Sayed Ahmed

Titre : Evaluation of the land resources for agricultural development - case study : El-Hammam Canal and its extension, NW Coast of Egypt

Auteur : Sayed, Ahmed Sayed Ahmed

Université de soutenance : Universität Hamburg

Grade : Doktorgrades der Naturwissenschaften 2013

Subject : soil evaluation , agricultural development , Egypt , calcisol

Résumé
Beside the region of the Nile Valley and Delta the North Western coast of Egypt is considered as one of the most important regions for land reclamation for agricultural expansion and for tourism development projects. Dealing with this region, the thesis has two general objectives. The first is to evaluate the land resources of a part of this region for future agricultural development. Based on this study and the reports about other Egyptian land reclamation projects the objective of the second part is to assess different methods to qualify soil properties for irrigated land use. Here the focus is on the type of soil information (e.g. remote sensing, mapping, laboratory analysis), there spatial density as well as on the methods to come to a holistic assessments of the land suitability for different types of agriculture. The study area is lies between longitudes 29° 00’ and 28° 30’ E and latitudes 30° 30’ and 31° 00’ N adjacent to an irrigation channel (El-Hammam Canal) which is not under function in the western part. In total, the area has a size of about 650 km2 and has only a minor agricultural land use property due to small amounts of annual rainfall. To fulfill the aim of the study, 43 soil profiles representing the study area were morphologically described and sampled. In the laboratory, the soil samples were analyzed on their relevant physical, chemical and physico-chemical properties. Land use productivity is controlled by soil physical and chemical characteristics and their spatial distributions. Spatial data of soil properties were presented as individual maps by GIS (E. g. depth, salinity, reaction, calcium carbonate contents and exchangeable sodium percentage). To find the best priorities of agricultural land use within the studied area, the soils have been evaluated using the land capability and land suitability systems. These systems are based on the following parameters such as ; slope, topography, depth, texture, calcium carbonate content, gypsum content, salinity and alkalinity, cation exchangeable capacity, exchangeable sodium percentage and sodium adsorption ratio. Based on the actual soil properties, land capability and suitability for agricultural production were assessed using the six systems (American method -USDA, Storie index 1978 and 2008 ; Sys and Verhey 1978, Sys et al. 1993 ; ALES ; MicroLEIS). Results indicate that the area currently lacks high capability and land capability for the most systems are ranged between moderate or/ marginally suitability classes and non-suitable. Land capability of the study area according to Storie index (2008) varies from “good capability” to “non-agriculture” due to different limiting factors. The results show that, about 9.0 % of the evaluated soils have good capability ; about 12.3 % have fair capability ; 12.7 % are poor ; 29.6 % very poor and about 22.5 % are not suitable for agricultural use. There are about (11 % of the evaluated soils) are rocky outcrops and could be available to be settlements for farmers and Bedouins. According to MicroLEIS program, the capability varies from “good capability” (38.8 % of the evaluated soils) to “marginal or null suitable” (21.9 %) with about 28.3 % of the area having a moderate capability. The most limiting factors for current land suitability for major crops (wheat, sorghum, barley, alfalfa, maize, sunflower, tomato, melon, olive, fig, peach, guava and citrus) were soil depth, soil texture, drainage, calcium carbonate content, salinity and alkalinity. However, the potential suitability can be improved partly as main limitations coming from salinity and drainage could possibly be corrected, while soil depth and soil texture limitations have to seen as persistent. The main objective of this research was to compare different methods of land evaluation based on physical and chemical soil properties. The results showed that methods integrating properties to one index have a higher precision than methods that qualify soils on limitations for single parameters. Modern software controlled methods such as MicroLEIS are more suitable and easier to apply than parametric methods. The application of the Storie index (2008) and CERVATANA (land capability model) to the studied area already under agriculture reveals good agreement between evaluation results and actual land-use. The classifications on land suitably for crops generated by Sys et al. (1993) and the ALMAGRA system have some disadvantages regarding the soil salinity and soil texture ratings, however, if the systems are improved they produce reasonable results. Water must be supplied in sufficient quantity and desired quality, when the crop needs it. The drip irrigation can obviously be a way to improve the practice on light soil texture, aiming at maximizing water use efficiency, thus producing more crops per drop and helping to solve the water shortage crisis in the agricultural sector. Additionally to water supply an improvement of the soil productivity depends on the nutritional status of the soils. Here, the low organic carbon contents under natural conditions should be improved by fertilization and regular ploughing. However, the high contents of calcium carbonate needs a land use with adapted crops, which for the studied region are olive, fig and peach, tomatoes and sunflower. The exercise proved that the analysis of soil characteristics and the application of tools for land capability and suitability evaluation are a powerful tool for decision making and can be used as decision support system.

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