The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize based experiments were set up on six farmers' fields in Ward 5, Shurugwi. Th...The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize based experiments were set up on six farmers' fields in Ward 5, Shurugwi. Three tillage systems namely Post-Emergence Tied Ridging (PETR), Rip & Pot-Holing (RPH) and Conventional Mouldboard Ploughing (CMP) were integrated to three nutrient management regimes, i.e. a control with no fertility amelioration, pit-stored cattle manure band applied at 10 t/ha and the latter with an additional top dressing of ammonium nitrate (34.5% N) at 100 kg/ha. On each site the treatments were set up as a completely randomized split-plot block design replicated 3 times with tillage (water management) as the main treatment and fertility as the sub-treatment. CMP mimicked the farmers' common land preparation practice while PETR and RPH systems represented the improved water harvesting tillage techniques. Results revealed significant nutrient management effects right from the first season giving 3-year means of 1,298, 1,977 and 2,490 kg/ha for the control, manure and manure plus fertilizer treatments respectively. On the other hand, water harvesting tillage effects were insignificant initially (2003/4) but had beneficial effects in subsequent seasons (2004/5 and 2005/6) with 3-year grain yield means of 1,624, 2,032 and 2,108 kg/ha for CMP, PETR and RPH, respectively. Maximum yield benefits from integrating PETR and RPH with manure + AN fertility ameliorants amounted to 218 and 261% respectively, compared to CMP with no fertility amendment. The results therefore showed increased benefits when in-situ water harvesting tillage techniques are integrated with appropriate nutrient ameliorants giving realizable food security benefits to the farmer.展开更多
Large amount of pre-plant nitrogen (N) fertilizer results in low N use efficiency due to poor synchrony between soil N supply and maize N demand, especially during N sensitive growth stages. The objectives of the st...Large amount of pre-plant nitrogen (N) fertilizer results in low N use efficiency due to poor synchrony between soil N supply and maize N demand, especially during N sensitive growth stages. The objectives of the study were to compare growth and yield of maize (Zea rnays L.) under conventional and site-specific N management in a dryland farming system. The study, which was designed as randomized complete block design was conducted over three site-years under continuous maize cropping system in the semi-arid regions of the Limpopo Province in South Africa. Treatments of the study consisted of three N management strategies on a maize field planted to drought resistant SNK 2147 hybrid maize cultivar. Treatments were: (i) no N application (NO), (ii) site-specific N at variable rates ranging between 18 kg N/ha and 33 kg N/ha based on soil analysis results (N l) and (iii) conventional and uniform N application broadcasted during planting at 58 kg N/ha (N2). Sufficiency index as indication of N deficiency was determined using CCM-200 on maize leaves based on leaf numbers during maize vegetative growth stages V6, V10 and Vl4, and thereafter N was applied only when needed. The highest maize grain yield of 5.2 Mg/ha for N 1 was significantly higher (P 〈 0.05) than 3.2 Mg/ha and 4.0 Mg/ha of N0 and N2 in site-year I, respectively. Maize grain yield of 2.2 Mg/ha (Nl) at site-year ll was significantly higher (P _〈 0.05) than 1.7 Mg/ha of the NO. The maize growth and yield under N2 and N1 was compared, N1 required between 43% and 69% lesser N fertilizer as compared to N2 over site-years, and resulted in higher maize height, number of leaves per plant, leaf length, and leaf area than that of conventional N management strategy. Therefore, site-specific N management strategy sustains and improves growth and yield of maize using minimal N fertilizer as compared to conventional approach in low fertility soils of semi-arid regions in dryland farming systems. In examining the results of this study, there was a consistent benefit of site-specific N management strategy on improving growth and yield of maize while saving fertilizer use in small-scale dryland maize farming system.展开更多
The effective and efficient management of agricultural water use is crucial to enhance agricultural production to meet the demand of a rapidly growing population. The performance assessment studies are successfully us...The effective and efficient management of agricultural water use is crucial to enhance agricultural production to meet the demand of a rapidly growing population. The performance assessment studies are successfully used to describe the irrigation problems and provide remedial measures. In this study, the performance assessment of the twin main canals of the Gezira Scheme were examined and evaluated using a set of performance indicators. The analysis was made using 3 Landsat and 8 Modis data of 2001-2002, and results showed that the seasonal average values of water productivity, relative water supply, overall consumed ratio, depleted fraction and relative evapotranspiration were respectively 0.47, 0.72, 1.41, 0.75 and 0.57 kg·m^-3 for Gezira main canal, whereas the values for Managil main canal were 0.43, 0.54, 1.68, 0.71 and 0.50 kg·m^-3, respectively. The monthly average values of crop water deficit for Gezira and Managil were respectively 71 and 78 mm-month^-1. Considering the spatial variation in some indicators, the irrigation uniformity is deemed as poor according to Molden and Gates (1990). The analysis also showed that the gap between water demand and supply during winter season was glaringly high (46%).展开更多
Water scarcity is a challenge in many arid and semi-arid regions; this may lead to a series of environmental problems and could be stressed even further by the effects from climate change. This study focused on the wa...Water scarcity is a challenge in many arid and semi-arid regions; this may lead to a series of environmental problems and could be stressed even further by the effects from climate change. This study focused on the water resource management in Shanshan County, an inland arid region located in northwestern China with a long history of groundwater overexploitation. A model of the supply and demand system in the study area from 2006 to2030, including effects from global climate change,was developed using a system dynamics(SD)modeling tool. This SD model was used to 1) explore the best water-resource management options by testing system responses under various scenarios and2) identify the principal factors affecting the responses, aiming for a balance of the groundwater system and sustainable socio-economic development.Three causes were identified as primarily responsible for water issues in Shanshan: low water-use efficiency low water reuse, and increase in industrial waterdemand. To address these causes, a combined scenario was designed and simulated, which was able to keep the water deficiency under 5% by 2030. The model provided some insights into the dynamic interrelations that generate system behavior and the key factors in the system that govern water demand and supply. The model as well as the study results may be useful in water resources management in Shanshan and may be applied, with appropriate modifications, to other regions facing similar water management challenges.展开更多
The scarcity of water resources in Syria, due to its major arid to semi-arid climate (precipitation less 100 mm/year) in a large part of the country, imposes a better rainfall water management in the humid to semi-h...The scarcity of water resources in Syria, due to its major arid to semi-arid climate (precipitation less 100 mm/year) in a large part of the country, imposes a better rainfall water management in the humid to semi-humid Syrian coast (precipitation over 1,000 mm/year), where a high water quantity is lost in the sea. Various hydraulics constructions can be used aimed at a more rainfall water preservation: superficial wells, trenches, ponds, hilly lakes and small dams. Remote sensing techniques can help to build these constructions in places where the geomorphology is appropriate, and the filtration rate relatively limited. They are emplaced according to an advanced remote sensing mapping technique, based on the combination of several thematic maps: tectonics-, linear lineament (including density), lithological facies drainage and filtration maps. This advanced mapping technique has been used to quantitatively verify ancient established constructions along the Syrian coast, and to propose optimal localizations for future hydraulics constructions. This technique presents a simple, quick and cheap solutions to be applied in Syria and the Arab world.展开更多
Assessment report of the Intergovernmental Panel on Climate Change (IPCC) highlighted the complex linkages between climate change and water. The likely warmer climate induced by the climate change is set to alter hy...Assessment report of the Intergovernmental Panel on Climate Change (IPCC) highlighted the complex linkages between climate change and water. The likely warmer climate induced by the climate change is set to alter hydrological cycle and the shifting pattern of the rainfall would affect the spatial and temporal distribution of runoff, soil moisture, and surface and groundwater reserves. Therefore, there is an urgent need to assess the impacts of climate change on water and devise adaptation measures including management structures and processes by which one can deal with this challenge. The paper highlights with the global overview of climate change impacts on water in the arid region, supported and substantiated through scientific evidence drawn from IPCC reports and other relevant documents. This paper provides an overview of water resource management challenges including transboundary geopolitical concerns documented across the world and emphasizes the importance of an integrated framework for adaptive policy making. Further, it examines the viable water resource management options for various sectors and regions and showcases some of the international best practices in adaptation and mitigation. The paper also explains the complementary role of traditional knowledge in coping with climate change risks and uncertainties and the need for a balanced view in designing adaptation and mitigation strategies.展开更多
Participatory irrigation management (PIM) is theoretically assumed to reduce poverty significantly, but its practical experience and challenges are yet researched and documented in Tanzania. The study aimed at asses...Participatory irrigation management (PIM) is theoretically assumed to reduce poverty significantly, but its practical experience and challenges are yet researched and documented in Tanzania. The study aimed at assessing challenges observed during implementation of PIM approach for food security in semi-arid areas of Tanzania. Data were collected through questionnaire, participatory rapid appraisal (PRA) tools, key informants interview, Focus Group Discussion (FGD), observation and literature review. Data collected from questionnaire were analyzed using SPSS. Data fi'om other methods were analyzed using content analysis. The study revealed that PIM approach has contribution in improving food security at household level due to involvement of communities in water management activities and decision making, which enhanced availability of irrigation water and increased crop production. However, there were challenges observed during implementation of the approach, including the minimum participation of beneficiaries in decision making during planning and designing stages, which means that inadequate devolution of power among scheme owners, inadequate and lack of transparency on income expenditure in water utilization associations (WUAs), water conflict among WUAs members, conflict between farmers and livestock keepers and conflict between WUAs and village government leaders regarding training opportunities and status. The rules and regulation of WUAs were not legally recognized by the national courts and few farmers who planted trees around water sources. However, it was realized that some of the mentioned challenges were rectified by farmers themselves and facilitated by government officials. The study recommends that the identified challenges need to be rectified for farmers to realize more on the importance of PIM approach as it was realized in other Asian countries.展开更多
文摘The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize based experiments were set up on six farmers' fields in Ward 5, Shurugwi. Three tillage systems namely Post-Emergence Tied Ridging (PETR), Rip & Pot-Holing (RPH) and Conventional Mouldboard Ploughing (CMP) were integrated to three nutrient management regimes, i.e. a control with no fertility amelioration, pit-stored cattle manure band applied at 10 t/ha and the latter with an additional top dressing of ammonium nitrate (34.5% N) at 100 kg/ha. On each site the treatments were set up as a completely randomized split-plot block design replicated 3 times with tillage (water management) as the main treatment and fertility as the sub-treatment. CMP mimicked the farmers' common land preparation practice while PETR and RPH systems represented the improved water harvesting tillage techniques. Results revealed significant nutrient management effects right from the first season giving 3-year means of 1,298, 1,977 and 2,490 kg/ha for the control, manure and manure plus fertilizer treatments respectively. On the other hand, water harvesting tillage effects were insignificant initially (2003/4) but had beneficial effects in subsequent seasons (2004/5 and 2005/6) with 3-year grain yield means of 1,624, 2,032 and 2,108 kg/ha for CMP, PETR and RPH, respectively. Maximum yield benefits from integrating PETR and RPH with manure + AN fertility ameliorants amounted to 218 and 261% respectively, compared to CMP with no fertility amendment. The results therefore showed increased benefits when in-situ water harvesting tillage techniques are integrated with appropriate nutrient ameliorants giving realizable food security benefits to the farmer.
文摘Large amount of pre-plant nitrogen (N) fertilizer results in low N use efficiency due to poor synchrony between soil N supply and maize N demand, especially during N sensitive growth stages. The objectives of the study were to compare growth and yield of maize (Zea rnays L.) under conventional and site-specific N management in a dryland farming system. The study, which was designed as randomized complete block design was conducted over three site-years under continuous maize cropping system in the semi-arid regions of the Limpopo Province in South Africa. Treatments of the study consisted of three N management strategies on a maize field planted to drought resistant SNK 2147 hybrid maize cultivar. Treatments were: (i) no N application (NO), (ii) site-specific N at variable rates ranging between 18 kg N/ha and 33 kg N/ha based on soil analysis results (N l) and (iii) conventional and uniform N application broadcasted during planting at 58 kg N/ha (N2). Sufficiency index as indication of N deficiency was determined using CCM-200 on maize leaves based on leaf numbers during maize vegetative growth stages V6, V10 and Vl4, and thereafter N was applied only when needed. The highest maize grain yield of 5.2 Mg/ha for N 1 was significantly higher (P 〈 0.05) than 3.2 Mg/ha and 4.0 Mg/ha of N0 and N2 in site-year I, respectively. Maize grain yield of 2.2 Mg/ha (Nl) at site-year ll was significantly higher (P _〈 0.05) than 1.7 Mg/ha of the NO. The maize growth and yield under N2 and N1 was compared, N1 required between 43% and 69% lesser N fertilizer as compared to N2 over site-years, and resulted in higher maize height, number of leaves per plant, leaf length, and leaf area than that of conventional N management strategy. Therefore, site-specific N management strategy sustains and improves growth and yield of maize using minimal N fertilizer as compared to conventional approach in low fertility soils of semi-arid regions in dryland farming systems. In examining the results of this study, there was a consistent benefit of site-specific N management strategy on improving growth and yield of maize while saving fertilizer use in small-scale dryland maize farming system.
文摘The effective and efficient management of agricultural water use is crucial to enhance agricultural production to meet the demand of a rapidly growing population. The performance assessment studies are successfully used to describe the irrigation problems and provide remedial measures. In this study, the performance assessment of the twin main canals of the Gezira Scheme were examined and evaluated using a set of performance indicators. The analysis was made using 3 Landsat and 8 Modis data of 2001-2002, and results showed that the seasonal average values of water productivity, relative water supply, overall consumed ratio, depleted fraction and relative evapotranspiration were respectively 0.47, 0.72, 1.41, 0.75 and 0.57 kg·m^-3 for Gezira main canal, whereas the values for Managil main canal were 0.43, 0.54, 1.68, 0.71 and 0.50 kg·m^-3, respectively. The monthly average values of crop water deficit for Gezira and Managil were respectively 71 and 78 mm-month^-1. Considering the spatial variation in some indicators, the irrigation uniformity is deemed as poor according to Molden and Gates (1990). The analysis also showed that the gap between water demand and supply during winter season was glaringly high (46%).
文摘Water scarcity is a challenge in many arid and semi-arid regions; this may lead to a series of environmental problems and could be stressed even further by the effects from climate change. This study focused on the water resource management in Shanshan County, an inland arid region located in northwestern China with a long history of groundwater overexploitation. A model of the supply and demand system in the study area from 2006 to2030, including effects from global climate change,was developed using a system dynamics(SD)modeling tool. This SD model was used to 1) explore the best water-resource management options by testing system responses under various scenarios and2) identify the principal factors affecting the responses, aiming for a balance of the groundwater system and sustainable socio-economic development.Three causes were identified as primarily responsible for water issues in Shanshan: low water-use efficiency low water reuse, and increase in industrial waterdemand. To address these causes, a combined scenario was designed and simulated, which was able to keep the water deficiency under 5% by 2030. The model provided some insights into the dynamic interrelations that generate system behavior and the key factors in the system that govern water demand and supply. The model as well as the study results may be useful in water resources management in Shanshan and may be applied, with appropriate modifications, to other regions facing similar water management challenges.
文摘The scarcity of water resources in Syria, due to its major arid to semi-arid climate (precipitation less 100 mm/year) in a large part of the country, imposes a better rainfall water management in the humid to semi-humid Syrian coast (precipitation over 1,000 mm/year), where a high water quantity is lost in the sea. Various hydraulics constructions can be used aimed at a more rainfall water preservation: superficial wells, trenches, ponds, hilly lakes and small dams. Remote sensing techniques can help to build these constructions in places where the geomorphology is appropriate, and the filtration rate relatively limited. They are emplaced according to an advanced remote sensing mapping technique, based on the combination of several thematic maps: tectonics-, linear lineament (including density), lithological facies drainage and filtration maps. This advanced mapping technique has been used to quantitatively verify ancient established constructions along the Syrian coast, and to propose optimal localizations for future hydraulics constructions. This technique presents a simple, quick and cheap solutions to be applied in Syria and the Arab world.
文摘Assessment report of the Intergovernmental Panel on Climate Change (IPCC) highlighted the complex linkages between climate change and water. The likely warmer climate induced by the climate change is set to alter hydrological cycle and the shifting pattern of the rainfall would affect the spatial and temporal distribution of runoff, soil moisture, and surface and groundwater reserves. Therefore, there is an urgent need to assess the impacts of climate change on water and devise adaptation measures including management structures and processes by which one can deal with this challenge. The paper highlights with the global overview of climate change impacts on water in the arid region, supported and substantiated through scientific evidence drawn from IPCC reports and other relevant documents. This paper provides an overview of water resource management challenges including transboundary geopolitical concerns documented across the world and emphasizes the importance of an integrated framework for adaptive policy making. Further, it examines the viable water resource management options for various sectors and regions and showcases some of the international best practices in adaptation and mitigation. The paper also explains the complementary role of traditional knowledge in coping with climate change risks and uncertainties and the need for a balanced view in designing adaptation and mitigation strategies.
文摘Participatory irrigation management (PIM) is theoretically assumed to reduce poverty significantly, but its practical experience and challenges are yet researched and documented in Tanzania. The study aimed at assessing challenges observed during implementation of PIM approach for food security in semi-arid areas of Tanzania. Data were collected through questionnaire, participatory rapid appraisal (PRA) tools, key informants interview, Focus Group Discussion (FGD), observation and literature review. Data collected from questionnaire were analyzed using SPSS. Data fi'om other methods were analyzed using content analysis. The study revealed that PIM approach has contribution in improving food security at household level due to involvement of communities in water management activities and decision making, which enhanced availability of irrigation water and increased crop production. However, there were challenges observed during implementation of the approach, including the minimum participation of beneficiaries in decision making during planning and designing stages, which means that inadequate devolution of power among scheme owners, inadequate and lack of transparency on income expenditure in water utilization associations (WUAs), water conflict among WUAs members, conflict between farmers and livestock keepers and conflict between WUAs and village government leaders regarding training opportunities and status. The rules and regulation of WUAs were not legally recognized by the national courts and few farmers who planted trees around water sources. However, it was realized that some of the mentioned challenges were rectified by farmers themselves and facilitated by government officials. The study recommends that the identified challenges need to be rectified for farmers to realize more on the importance of PIM approach as it was realized in other Asian countries.