Semi-arid Sudan Research Articles

Yield Performance and Stability Analysis of Promising Soybean Genotypes under Contrasting Environments in the Semi-arid Zone of Sudan

Background: The challenge to food security posed by climate change and coupled with the substantial rise in the global population, necessitate a shift in crop improvement programmes towards developing crop cultivars with stable and high yield potentials across a wide range of agro-ecological conditions. Methods: New high yielding crop varieties with stable performance across environments are enabling the expansion of their production area into non-traditional environments with semi-arid climates. Soybean (Glycine max L.), a tropical leguminous crop, has received significant attention as a target crop in breeding programmes for adaptation to semi-arid environments, due to its low water content, high nutritive value and the capacity to produce a variety of products. The objective of this study was to asses yield performance and stability of promising soybean genotypes under contrasting environments in the semi-arid zone of Sudan. We evaluated five soybean genotypes using a split plot design with environment as the main plot and genotype as the subplot. Result: Combined ANOVA showed significant differences among the genotypes, environment and genotype x environment interaction. Moreover, significant positive relationships were observed between seed yield and number of days to 95% flowering, 100-seed weight, leaf area and number of pods per plant. AMMI stability values revealed significant differences among the genotypes and genotype-by-environment main effects for seed yield. Similarly, results of GGE biplot showed significant contributions of genotypes and genotype-by-environment main effects. The stability models enabled us to identify genotypes with superior performance to specific environments. TGX 1904-6F, was found to be the most stable genotype with appreciable seed yield and adaptability across all environments that can be recommended for release to farmers in semi-arid Sudan.

Seasonal variation of carbon fluxes in a sparse savanna in semi arid Sudan

BackgroundLarge spatial, seasonal and annual variability of major drivers of the carbon cycle (precipitation, temperature, fire regime and nutrient availability) are common in the Sahel region. This causes large variability in net ecosystem exchange and in vegetation productivity, the subsistence basis for a major part of the rural population in Sahel. This study compares the 2005 dry and wet season fluxes of CO2 for a grass land/sparse savanna site in semi arid Sudan and relates these fluxes to water availability and incoming photosynthetic photon flux density (PPFD). Data from this site could complement the current sparse observation network in Africa, a continent where climatic change could significantly impact the future and which constitute a weak link in our understanding of the global carbon cycle.ResultsThe dry season (represented by Julian day 35–46, February 2005) was characterized by low soil moisture availability, low evapotranspiration and a high vapor pressure deficit. The mean daily NEE (net ecosystem exchange, Eq. 1) was -14.7 mmol d-1 for the 12 day period (negative numbers denote sinks, i.e. flux from the atmosphere to the biosphere). The water use efficiency (WUE) was 1.6 mmol CO2 mol H2O-1 and the light use efficiency (LUE) was 0.95 mmol CO2 mol PPFD-1. Photosynthesis is a weak, but linear function of PPFD. The wet season (represented by Julian day 266–273, September 2005) was, compared to the dry season, characterized by slightly higher soil moisture availability, higher evapotranspiration and a slightly lower vapor pressure deficit. The mean daily NEE was -152 mmol d-1 for the 8 day period. The WUE was lower, 0.97 mmol CO2 mol H2O-1 and the LUE was higher, 7.2 μmol CO2 mmol PPFD-1 during the wet season compared to the dry season. During the wet season photosynthesis increases with PPFD to about 1600 μmol m-2s-1 and then levels off.ConclusionBased on data collected during two short periods, the studied ecosystem was a sink of carbon both during the dry and wet season 2005. The small sink during the dry season is surprising and similar dry season sinks have not to our knowledge been reported from other similar savanna ecosystems and could have potential management implications for agroforestry. A strong response of NEE versus small changes in plant available soil water content was found. Collection and analysis of flux data for several consecutive years including variations in precipitation, available soil moisture and labile soil carbon are needed for understanding the year to year variation of the carbon budget of this grass land/sparse savanna site in semi arid Sudan.

Canopy – air temperature differential on what varieties grown under different soil moisture regime on semi-arid Sudan savanna

Canopy – air temperature differential on what varieties grown under different soil moisture regime on semi-arid Sudan savanna

Assessment of soil organic carbon in semi-arid Sudan using GIS and the CENTURY model

Using the UNFCCC as a basis, and the objectives of estimating soil organic carbon (SOC) changes during the period 1900–2100, a spatially explicit database of climate, land cover and soil texture was compiled for a 262,000 km 2 region in semi-arid Sudan. The area is characterized by low input cultivation of millet, sorghum and sesamé combined with livestock grazing. By integrating the database with the CENTURY ecosystem model, we were able to estimate historical, current and future pools of SOC as a function of land management and climate. The SOC (upper 20 cm) decrease from 1900 to 2000 was estimated to be 6·8 Mt and the maximum potential carbon sink (SOC increase) for the period 2000 to 2100 was estimated to be 17 Mt. Cropland and grassland lost 293 and 152 t SOC km −2 respectively whereas the savannahs gained 76 t SOC km −2 from 1900 to 2000. The SOC sequestration scenario simulated during 2000–2100 recovered 94, 84 and 75 t km −2 for cropland, grassland and savannah respectively. In addition to climate and soils, cropping intensity, fallow periods, fire frequency and grazing intensity also influence cropland SOC variation. Grassland and savannah SOC variations depend on grazing intensity and fire return interval. Land management may affect future amounts of SOC in semi-arid areas thereby turning them from sources into sinks of carbon. SOC estimates were reasonably consistent with measurements ( r 2=0·70, n=13).

Effect of planting methods and soil moisture on cassava performance in the semi-arid Sudan savanna belt of Nigeria

Effect of planting methods and soil moisture on cassava performance in the semi-arid Sudan savanna belt of Nigeria

The breeding season and diet of Arvicanthis in northern Nigeria

ABSTRACTThe breeding season and diet of the rat Arvicanthis was monitored from December 1983 to November 1985 in the semi-arid Sudan savanna at Kano, Nigeria, West Africa. Breeding began 1–2 months before the start of the rainy season and ceased at the beginning of the dry season. The diet of Arvicanthis was omnivorous, but with seasonal differences. Monocotyledons and dicotyledons predominated in the diet in the dry season, with seeds and insects increasing in the diet in the rainy season. The major differences between the ecology of Arvicanthis at Kano and on the East African savanna were that in East Africa the breeding season is longer and begins after the start of the rainy season. These and other dissimilarities between the biology of Arvicanthis in the two areas could be due to the effect of climatic differences on food supply and to the possible existence of different taxonomic groupings of Arvicanthis in the two regions.

Olsson, Lennart "An Integrated Study of Desertification: Applications of Remote Sensing, GIS and Spatial Models in Semi-Arid Sudan" (Book Review)

Olsson, Lennart "An Integrated Study of Desertification: Applications of Remote Sensing, GIS and Spatial Models in Semi-Arid Sudan" (Book Review)

Review of: “ A n Integrated Study of Desertification: Applications of Remote Sensing, GIS and Spatial Models in Semi-arid Sudan. By L. OLSSON. (Malmo: CWK Gleerup, Lund Studies in Geography, Department of Geography, 1985.) [Pp. 170.

(1987). Review of: “ A n Integrated Study of Desertification: Applications of Remote Sensing, GIS and Spatial Models in Semi-arid Sudan. By L. OLSSON. (Malmo: CWK Gleerup, Lund Studies in Geography, Department of Geography, 1985.) [Pp. 170.] International Journal of Remote Sensing: Vol. 8, No. 4, pp. 676-677.

The human factor in development: some lessons from rural Sudan?

This paper discusses some of the findings from research done by staff and postgraduate students of the Departments of Geography of the University College of Swansea, UK and the University of Khartoum, Sudan, under the general theme of ‘Factors inhibiting rural development in arid and semi-arid Sudan’. The paper's principal conclusion is that Sudan's rural problems stem only in part from the current world economic crisis, environmental deterioration and other national problems, but are primarily a question of human relations, between management and labour, government and people with top-down programmes for development. In the past insufficient thought has been given to the views and aspirations of the participants in rural development schemes, and as to how these programmes integrate together.

The adaptability of a rural water supply system to extreme rainfall anomalies in central Sudan

Rural water supply in semi-arid Sudan is closely dependent upon annual rainfall. Yet in discussions on the consequences of rainfall anomalies in this climatically marginal zone, the impact on rural water availability is rarely examined in detail. A case study is presented from the White Nile Province of the impact of two anomalous wet seasons on the rural water system: 1978, the second wettest year this century in north-central Sudan and 1983, one of the six driest. The major sources of water for the rural community are identified as being Nile water, hand-dug wells and mechanized boreholes. The operation of a rural water supply system is outlined which focuses on physical and managerial components and the mobility of population and livestock. Although 1983 produced barely one large fall of > 25mm compared to five such falls in 1978, in several localities water was as abundant in April 1984 as in April 1979. The physical and managerial components are shown to be unable to cope fully with such rainfall surplus or deficit, but the variable pattern of human migration and transhumance results in the balancing of water supply and demand. It is suggested that rural water planning should capitalize on this human flexibility and also that studies be initiated on the impact of decadal rainfall anomalies on rural water supply.