Abstract: This study was conducted to investigate the suitability of white and red pulp guava fruits grown in Sudan for production of concentrates. The two cultivars were processed to concentrates by evaporation under normal atmospheric pressure. The two concentrates were evaluated physicochemically against an Indian commercial concentrate control. White pulp guava is characterized by high level of vitamin C (250 mg/100g), and similar levels of sugars compared to the red pulp guava. The pulping process significantly (P≤0.05) reduced the levels of vitamin C and sugars. Concentration of the juice to 17.00 and 19.00% total soluble solids in white and red guavas, respectively, resulted in further loss in vitamin C (134.9; 125.4 mg/100g, respectively), and increase in total sugars from 3.17 to 15.32% in the white one, and from 3.34 to 16.14% in the red one. Keywords: White and red guava, concentrate, processing characteristics.

Abstract: Reducing sugars diminishing during reconditioning of cold- stored (3-4°C) Kondor and Markies processing potato cultivars were investigated. Temperature of 18 °C (73-78% RH) has significantly (P ≤ 0.05) reduced the sugar accumulation during 25 days storage in both potato cultivars from1.82 to 0.09(%) and from 3.3 to 0.25(%) in Markies and Kondor respectively. The reduction in reducing sugars accumulation reached the recommended level for potato processing (0.25-0.50 %). No adverse effects were recorded during the reconditioning period on the potato quality parameters such as tubers fresh weight loss, dry matter content and potato chips yield. Keywords: Potato, varieties, sugars, processing, reconditioning.

Abstract: Climate change constitutes a significant constraint to agricultural development and fruition through perturbation of rainfall. Areas located in the eastern part of Rwanda are more vulnerable than other regions of the country, owing to their topography, geology and climatology. Comprehensive hydro-geospatial information will unveil its potential irrigation capacity and further suitable irrigation solutions for the region. This study aimed at mapping the hydrological and geological characteristics and other geospatial features of irrigable lands of Bugesera region, in the Eastern Province of Rwanda, using remote sensing and geographic information system’s tools. The methodological approach consisted of processing Aster radar satellite image of 2006 and a topographic map of 1998 to enable designing a Digital Elevation Model (DEM) and producing different types of map layers using appropriate software packages ( ILWIS 3.3, Erdas 8.7 and ArcGIS 9.2). These maps were interpreted to describe and classify lands by slope, water proximity, percentage of clay and sand in the soil, and land use/ cover types. This will further assist to determine the most suitable areas for irrigation and derive the characteristics of potential irrigation methods for each land. This is a useful planning tool for optimizing agriculture development in the Eastern Region of Rwanda. Keywords: Spatial information, Aster Image, Digital Elevation Model, irrigation.

Abstract: In the year 2002, USAID’s FEWSNET programme started warning about a looming food crisis in Bugesera region of the Eastern Province of Rwanda, which would be exacerbated by water scarcity. This study attempted to map potential irrigable lands of that agro ecological zone using spatial information to determine the most suitable areas that can be included in the national development agenda. The methodology consisted of overlaying different irrigation parameters derived from the processing of the Landsat Aster 2006 radar image and Digital Elevation Models (DEM) using appropriate software packages, namely ILWIS 3.3, ERDAS Imagine 8.7 and ArcGIS 9.2. These tools enabled us determine Land use and Land cover classification of the study area that fits to the soil characteristics, geology, topography and hydrology of Bugesera highlands. Maps resulting from this overlaying process display different types of layer classes according to each irrigation purpose. In most of the cases, only two classes of slope gradients, the soil texture, water proximity, and Land use/ cover type were found to be the most economic and suitable for irrigation purpose in Bugesera region, owing to their high water holding capacity. These were related to surface irrigation and all other possible types of irrigation, mainly sprinkler and drip irrigation. Overlaying these spatial models is an new way of thinking for irrigation development and agricultural water optimization in the Eastern Region of Rwanda in general and Bugesera region in particular. Keywords: Spatial information, satellite Image, topographic map, Digital Elevation Model, irrigation, Land use, Land cover.

Abstract: Three Landsat-5 TM images were analyzed to estimate actual ET of 47 Misgas for irrigated sorghum in Gash Delta, Sudan. Moreover water use efficiency (WUE) was estimated. Surface Energy Balance Algorithm for Land (SEBAL) developed by Bastiaanssen . (1998a, 1998b) was used to estimate land surface variables and actual ET. The results show that highest crop water productivity (CWP) was obtained by Kassala block which was 0.48 Kg m-3 followed by Metateib block 0.35 Kg m-3 with a bit low evapotranspiration (ET). In contrast, Mekali block obtained the minimum CWP 0.20 Kg m-3 and consuming much water (ET ≈ 606 mm) compared with other five blocks. The results show the WUE obtained by SEBAL was 46% compared with 45% in previous study, the difference between both was very small which is about 1%. The cultivated Misga was identified by using binary images of NDVI and actual ET. The boundaries of Misga were compared with that drawn manually in actual ET image and both boundaries were approximately same except for horticulture area. This result shows that the binary images of NDVI and actual ET can be used as a simple method for identifying cultivated area. Keywords: land surface variables, evapotranspiration, remote sensing, SEBAL, Gash Delta.