Twenty-six soil samples were collected from five soil profiles at different climatological and ecological regions in central Sudan. Soil profile was dug in each studied area and morphological profile description was c...Twenty-six soil samples were collected from five soil profiles at different climatological and ecological regions in central Sudan. Soil profile was dug in each studied area and morphological profile description was carried out for different horizons. All samples were analyzed using two different methods to determine Cation Exchange Capacity (CEC) and exchangeable sodium percentage (ESP). Statistical analysis (T-test) was used in order to investigate the differences between soil samples for the studied locations. Significant differences appeared when compared the two methods for CEC determination at Gedaref area, Wad Medani and Nile flood plain and that appeared in evaluation of ESP at Nile flood plain and Shambat area. The results also revealed that, the developed method used in this study was more practical, simple and reliable for determination of CEC and ESP as the currently used in most soil laboratories. In addition, it will be safer than the other methods in some problematic soils. The adoption of this developed method is advisable because it is less time consuming as it omits the washing step. In contrast, the old method cannot be a good substitute in laboratories which have no possibility to determine sodium by using flame photometer. We conclude that when the developed method is used to determine CEC and ESP time will be saved, that fewer amounts of chemicals will be used and that accurate results will be achieved.展开更多
Despite the CaCO<sub>3</sub> estimation using titration method was not reliable, but up to the present time, some soil laboratories in Sudan still used this method. The objective of this study was to compa...Despite the CaCO<sub>3</sub> estimation using titration method was not reliable, but up to the present time, some soil laboratories in Sudan still used this method. The objective of this study was to compare and assess the results of calcimetric and titrimetric methods of quantitative estimation for soil calcium carbonate of different soils in Sudan. 26 soil samples from five soil profiles were collected from different climatological and ecological regions in central Sudan. CaCO<sub>3</sub> equivalent was estimated using calcimeter and titration methods in order to find accurate, rapid and suitable method for soils of Sudan. The results revealed that there are no significant differences between calcimeter and titration methods for calcium carbonate estimation in all studied samples except in samples from Gedaref area. We concluded that when the Calcimeter method used for CaCO<sub>3</sub> estimation, the differences between one person and another in detecting titration end point would be avoided, rapid and accurate results would be obtained compared to titration method. Additionally, time would be saved;fewer amounts of chemicals would be used. From this study, we highly recommend using calcimeter method for CaCO<sub>3</sub> estimation for soils of Sudan.展开更多
Climatic variability is one of the main constraints of agriculture in Mali, which will certainly affect long-term sorghum yields. The objective of the present study was to assess the effect of climate variability on s...Climatic variability is one of the main constraints of agriculture in Mali, which will certainly affect long-term sorghum yields. The objective of the present study was to assess the effect of climate variability on sorghum production areas by 2050 in the Sudanian and Sahelian zones of Mali considering three climate scenarios: current scenarios (RCP 2.5), optimistic scenarios (RCP 4.5) and pessimistic scenarios (RCP 8.5). Therefore, 11,010 occurrence points of sorghum (<em>Sorghum bicolor</em>) were collected and associated with the environmental variables of the three climatic scenarios according to the maximum entropy approach (Maxent). Sorghum environmental data and points of occurrence were obtained from AfriClim and GBIF databases, respectively. The correlations carried out and the Jackknife test allowed us to identify variables that contributed more to the performance of the model. Overall, in the Sudanian zone, the suitable area for sorghum production which currently represents 37% of the area of the district of Koulikoro will increase up to 51% by 2050 considering the optimistic scenario (RCP 4.5). Furthermore, considering the pessimistic scenario (RCP 8.5), the suitable zones for sorghum production will experience a decrease of 10%. In the Sahelian zone, the suitable zones for sorghum production that represent 55% of San district area considering the RCP 2.5 scenario will experience a decline of 24% by 2050 considering both the optimistic (RCP 4.5) and pessimistic (RCP 8.5) scenarios. It is suggested to carry out investigations on potential sorghum yield prediction in both study areas in order to identify suitable production areas of the crop in the near future (2050) and long term (2100) as adaptation strategies and resilience of farmers to climate c<em></em>hange.展开更多
Nigeria is a country endowed with alluvial aquifers that occur along major river valleys, in low lying areas which are frequent to flooding during the rainy season. They are scattered across the ecological zones of Gu...Nigeria is a country endowed with alluvial aquifers that occur along major river valleys, in low lying areas which are frequent to flooding during the rainy season. They are scattered across the ecological zones of Guinea savannah, Sudan savannah and the Sahel Savannah and are the thickest along the river Niger and river Benue. The irrigated flood plains (Fadama) are formed by the deposition of transported weathered exogenic terrigenous materials derived from the surrounding basement rocks. These shallow aquifers are mostly unconfined and are recharged through flash flooding events which make them hold great groundwater resources for dry season farming. The fertility of the soils with their residual moisture content makes them attractive for dry season farming. The potential and importance of Fadama agriculture for food production and economic development are crucial, given the recent rising food prices, climatic changes, environmental risks associated with “modern” agriculture, modelled farming systems and population growth. Fadama areas are therefore of critical importance to the survival and economic development of millions of rural dwellers. This paper reviews the groundwater potential of the Floodplains of Fadama for dry farming systems in semi-arid northern Nigeria.展开更多
文摘Twenty-six soil samples were collected from five soil profiles at different climatological and ecological regions in central Sudan. Soil profile was dug in each studied area and morphological profile description was carried out for different horizons. All samples were analyzed using two different methods to determine Cation Exchange Capacity (CEC) and exchangeable sodium percentage (ESP). Statistical analysis (T-test) was used in order to investigate the differences between soil samples for the studied locations. Significant differences appeared when compared the two methods for CEC determination at Gedaref area, Wad Medani and Nile flood plain and that appeared in evaluation of ESP at Nile flood plain and Shambat area. The results also revealed that, the developed method used in this study was more practical, simple and reliable for determination of CEC and ESP as the currently used in most soil laboratories. In addition, it will be safer than the other methods in some problematic soils. The adoption of this developed method is advisable because it is less time consuming as it omits the washing step. In contrast, the old method cannot be a good substitute in laboratories which have no possibility to determine sodium by using flame photometer. We conclude that when the developed method is used to determine CEC and ESP time will be saved, that fewer amounts of chemicals will be used and that accurate results will be achieved.
文摘Despite the CaCO<sub>3</sub> estimation using titration method was not reliable, but up to the present time, some soil laboratories in Sudan still used this method. The objective of this study was to compare and assess the results of calcimetric and titrimetric methods of quantitative estimation for soil calcium carbonate of different soils in Sudan. 26 soil samples from five soil profiles were collected from different climatological and ecological regions in central Sudan. CaCO<sub>3</sub> equivalent was estimated using calcimeter and titration methods in order to find accurate, rapid and suitable method for soils of Sudan. The results revealed that there are no significant differences between calcimeter and titration methods for calcium carbonate estimation in all studied samples except in samples from Gedaref area. We concluded that when the Calcimeter method used for CaCO<sub>3</sub> estimation, the differences between one person and another in detecting titration end point would be avoided, rapid and accurate results would be obtained compared to titration method. Additionally, time would be saved;fewer amounts of chemicals would be used. From this study, we highly recommend using calcimeter method for CaCO<sub>3</sub> estimation for soils of Sudan.
文摘Climatic variability is one of the main constraints of agriculture in Mali, which will certainly affect long-term sorghum yields. The objective of the present study was to assess the effect of climate variability on sorghum production areas by 2050 in the Sudanian and Sahelian zones of Mali considering three climate scenarios: current scenarios (RCP 2.5), optimistic scenarios (RCP 4.5) and pessimistic scenarios (RCP 8.5). Therefore, 11,010 occurrence points of sorghum (<em>Sorghum bicolor</em>) were collected and associated with the environmental variables of the three climatic scenarios according to the maximum entropy approach (Maxent). Sorghum environmental data and points of occurrence were obtained from AfriClim and GBIF databases, respectively. The correlations carried out and the Jackknife test allowed us to identify variables that contributed more to the performance of the model. Overall, in the Sudanian zone, the suitable area for sorghum production which currently represents 37% of the area of the district of Koulikoro will increase up to 51% by 2050 considering the optimistic scenario (RCP 4.5). Furthermore, considering the pessimistic scenario (RCP 8.5), the suitable zones for sorghum production will experience a decrease of 10%. In the Sahelian zone, the suitable zones for sorghum production that represent 55% of San district area considering the RCP 2.5 scenario will experience a decline of 24% by 2050 considering both the optimistic (RCP 4.5) and pessimistic (RCP 8.5) scenarios. It is suggested to carry out investigations on potential sorghum yield prediction in both study areas in order to identify suitable production areas of the crop in the near future (2050) and long term (2100) as adaptation strategies and resilience of farmers to climate c<em></em>hange.
文摘Nigeria is a country endowed with alluvial aquifers that occur along major river valleys, in low lying areas which are frequent to flooding during the rainy season. They are scattered across the ecological zones of Guinea savannah, Sudan savannah and the Sahel Savannah and are the thickest along the river Niger and river Benue. The irrigated flood plains (Fadama) are formed by the deposition of transported weathered exogenic terrigenous materials derived from the surrounding basement rocks. These shallow aquifers are mostly unconfined and are recharged through flash flooding events which make them hold great groundwater resources for dry season farming. The fertility of the soils with their residual moisture content makes them attractive for dry season farming. The potential and importance of Fadama agriculture for food production and economic development are crucial, given the recent rising food prices, climatic changes, environmental risks associated with “modern” agriculture, modelled farming systems and population growth. Fadama areas are therefore of critical importance to the survival and economic development of millions of rural dwellers. This paper reviews the groundwater potential of the Floodplains of Fadama for dry farming systems in semi-arid northern Nigeria.
