Determining the Magnitude of High Spot Lands by using Remote Sensing in Irrigated Schemes Case Study: Al Rahad Agricultural Scheme-Sudan

High spot lands are one of the most serious problems facing the irrigated agricultural production sector of the Sudan. As well, water and wind erosion, and silt deposits are the major environmental hazards causing land degradation in most parts of the irrigated sector. An understanding of the extent and magnitude of these hazards on various field surfaces is essential for the selection of appropriate control measures. The objective of this study was to identify and investigate the magnitude of high spot lands. Data from satellite images for four different years (1987-2013) were used to measure and quantify the high spot areas at four selected sites under the study areas. Also, personal communication with farmers in the study area was carried out. The satellite images showed variations of land cover in the study areas during years 1987-2013. The high spot lands covered 1.4 % of the total area till 1987 and increased to 3.3 %, 4.2 % and 6.3 % in 2000, 2005 and 2013, respectively. Data from satellite images for the year 1987 and 2013 showed that the density of uneven spots in 2013 was higher than that in 1987. The analysis showed that some changes in orientation of Abu XX at some sites were initially made to accommodate some of the natural elevation differences. The general trend of uneven area was randomly distributed. The results of the analysis of different remote sensing data using GIS proved the presence of high spots and elevation differences within the scheme. It seems that the continuous plowing pattern by the ridger in most cases without considering elevation and slope differences have largely contributed in the creating more high spot lands by the transportation of the soil by the plowing implements. The laboratory soil analysis showed similar soil characteristics of samples collected from high spot lands compared with the nearby original soils of even areas. It can be concluded that high spot lands increased at an annual rate of 0.2 % and accordingly, it threatens agricultural production in the study area by the loss of potential yield of the left-out high spot areas. Detailed soil and land survey investigations based on remote sensing and GIS techniques are highly recommended to identify all high spot areas in the irrigated sector in terms of location, size and soil characteristics.