The impact of nitrogen deposition on natural and semi-natural ecosystems
In: Environmental pollution Vol. 3
6 Ergebnisse
Sortierung:
In: Environmental pollution Vol. 3
Flood-based farming is among the potential options in ensuring access to water for crop and livestock production for small-scale farmers in the arid and semiarid lowlands of sub-Saharan Africa, and Ethiopia in particular. Flood-based irrigation while inexpensive is rooted in tradition in many rural communities which is in contrast to many other irrigation types which are unavailable (in terms of water source, technology or capacity) or are costly to develop. Spate irrigation has been practiced in different parts of Ethiopia for many decades, but it was only recently that it gained the government's attention. This study was conducted through a review and informal discussion with the objectives of documenting the current status, trends and prospects of spate irrigation in the country and the associated challenges, taking cases of selected schemes in different regional states. The study revealed that spate irrigation is expanding either through improvement of traditional schemes or by developing new ones. Neither the traditional nor modern schemes are free of challenges. The traditional schemes suffer from floods that damage their diversion structures, while poor design and construction of diversion structures have led to the failure of new ones. A range of socio-technical improvements in the planning, implementation and operation of schemes is proposed, including the design of headworks and canals consistent with the size and nature of expected flows, structures to minimize sedimentation, building capacity of farmers and district officers, and monitoring and improving the management that currently adversely impacts the performance of the schemes. Consulting farmers at every stage of the development, and building the capacity of engineers to deal with the unique nature of spate flows are the most likely interventions to ensure successful agricultural production using spate irrigation.
BASE
In the Blue Nile Basin of Ethiopian highlands, rainfall distribution is extremely uneven both spatially and temporally. Drought frequently results in crop failure, while high rainfall intensities result in low infiltration and high runoff causing soil erosion and land degradation. These combined factors contribute to low agricultural productivity and high levels of food insecurity. Poor land management practices coupled with lack of effective rainwater management strategies aggravate the situation. Over the past two decades, however, the Government of Ethiopia has attempted to address many of these issues through a large-scale implementation of a number of soil and water conservation measures. Despite the success of interventions, uptake and adoption remains low. The conceptual framework of this study is based on the premise that farmers are more likely to adopt a combination of rainwater management technologies as adaptation mechanism against climate variability and agricultural production constraints. This contrasts the previous work that typically examined a single technology without considering the interdependence between technologies. Data used in this study come from household survey in seven watersheds in the Ethiopian Blue Nile Basin. A multivariate probit model was used to account for the potential correlation and interdependence of various components of rainwater management technologies. Our results suggest that rainwater management technologies are related with each other; hence, any effort to promote the adoption of rainwater management technologies has to consider such interdependence of technologies, or failure to do so may mask the reality that farmers face a set of choices in their adoption decisions.
BASE
Understanding the different perceptions of the local community regarding the use and management of common pool resources, such as exclosures, could better support targeted interventions by government and development partners. Here, we report on a study conducted in the Gomit watershed, northwestern Ethiopia, using a survey and key informant interviews, to examine community perceptions on (a) the biophysical condition (i.e., challenge of land degradation and restoration), (b) the action situations (user's access to and control over resources and decision-making processes involved in taking actions in managing the exclosure), (c) actors' interactions (formal and informal institutions involved in the management of exclosures), and (d) perceived outcomes (benefits and tradeoffs of managing exclosures). Many people in the Gomit watershed recognize land degradation as a serious problem and believe that exclosures support restoration of degraded landscapes and improve ecosystem services. Informal institutions play a key role in managing exclosures by improving benefit sharing and mobilizing the local community for collective action. However, some community members have concerns about recent expansion of exclosures because of (a) limited short-term derived benefits, (b) reductions in fuelwood availability, (c) increased degradation of remaining communal grazing lands, and (d) poor participation of marginalized groups in decision making. Addressing such concerns through the promotion of short-term benefits of exclosures and increasing community participation in decision-making and benefit sharing is crucial. The study provides evidence to support government and development partners on the establishment and management of exclosures through identifying the benefits and drawbacks as perceived by different sectors of the community.
BASE
Sustainable participatory watershed management is an approach promoted by the Ethiopian government to restore natural resources and agricultural productivity across the country. This comparative study between six watershed programs shows that this approach increases farmers' food security and incomes (around 50% on average), as well as their resilience to drought and other climate shocks. However, the study also confirms that the nature and scale of impact can vary significantly between watershed programs. The success of watershed management depends on multiple factors from the hydrological profile of the watershed to the local social and economic environment. Tailoring watershed interventions to the local context, associating conservation and livelihoods activities, and providing further financial and technical support to watershed committees are among the recommendations of this paper.
BASE
In Ethiopia, exclosures in landscapes have become increasingly important to improving ecosystem services and reversing biodiversity losses. The present study was conducted in Gomit watershed, northern Ethiopia, to: (i) investigate the changes in vegetation composition, diversity and aboveground biomass and carbon following the establishment of exclosures; and (ii) analyse the economic returns of aboveground carbon sequestration and assess the perception of local communities on land degradation and exclosures. A space-for-time substitution approach was used to detect the changes in aboveground carbon, species composition, and diversity. Exclosures of 1-, 2-, 3-, 4-, 5-, and 7-years-old and a communal grazing land were selected. Household surveys, key informant interviews, and a financial analysis were used to assess the perception of local communities and the value of exclosure impacts, respectively. Significant (P = 0.049) differences in species diversity and considerable increases in aboveground carbon (ranged from 0.6 to 4.2 t C ha-1), CO2 storage (varied between 2.1 and 15.3 t CO2 ha-1), woody species composition, and richness (ranged from five to 28) were observed following the establishment of exclosures. Exclosures generated temporary certified emission reductions (tCER) of 3.4, 2.1, 7.5, 12.6, 12.5, and 15.3 Mg CO2 ha-1 after 1, 2, 3, 4, 5, and 7 years, respectively. The net present value (NPV) of the aboveground carbon sequestered in exclosures ranged from US$6.6 to US$37.0 per hectare and increased with exclosure duration. At a watershed level, 51.4 Mg C ha-1 can be sequestered, which represents 188.6 Mg CO2 ha-1, resulting in tCER of 139.4 Mg CO2 ha-1 and NPV of US$478.3 per hectare. This result would suggest that exclosures can potentially improve local communities' livelihoods beyond rehabilitating degraded lands if carbon stored in exclosures is traded. Communities in the watershed demonstrated that exclosures are effective in restoring degraded lands and they are benefiting from increased fodder production and reduced impacts of soil erosion. However, the respondents are also concerned over the sustainability of exclosure land management, as further expansion of exclosures aggravates degradation of remaining communal grazing lands and causes fuel wood shortages. This suggests that the sustainability of exclosure land management can be attained only if these critical concerns are addressed by a joint effort among government agencies, nongovernmental organizations, and communities.
BASE