Suchergebnisse

Improvements in on-farm water and soil fertility management through water harvesting may prove key to up-grade smallholder farming systems in dry sub-humid and semi-arid sub-Sahara Africa (SSA). The currently experienced yield levels are usually less than 1 t ha-1, i.e., 3-5 times lower than potential levels obtained by commercial farmers and researchers for similar agro-hydrological conditions. The low yield levels are ascribed to the poor crop water availability due to variable rainfall, losses in on-farm water balance and inherently low soil nutrient levels. To meet an increased food demand with less use of water and land in the region, requires farming systems that provide more yields per water unit and/or land area in the future. This thesis presents the results of a project on water harvesting system aiming to upgrade currently practised water management for maize (Zea mays, L.) in semi-arid SSA. The objectives were to a) quantify dry spell occurrence and potential impact in currently practised small-holder grain production systems, b) test agro-hydrological viability and compare maize yields in an on-farm experiment using combinations supplemental irrigation (SI) and fertilizers for maize, and c) estimate long-term changes in water balance and grain yields of a system with SI compared to farmers currently practised in-situ water harvesting. Water balance changes and crop growth were simulated in a 20-year perspective with models MAIZE1&2. Dry spell analyses showed that potentially yield-limiting dry spells occur at least 75% of seasons for 2 locations in semi-arid East Africa during a 20-year period. Dry spell occurrence was more frequent for crop cultivated on soil with low water-holding capacity than on high water-holding capacity. The analysis indicated large on-farm water losses as deep percolation and run-off during seasons despite seasonal crop water deficits. An on-farm experiment was set up during 1998-2001 in Machakos district, semi-arid Kenya. Surface run-off was collected and stored in a 300m3 earth dam. Gravity-fed supplemental irrigation was carried out to a maize field downstream of the dam. Combinations of no irrigation (NI), SI and 3 levels of N fertilizers (0, 30, 80 kg N ha-1) were applied. Over 5 seasons with rainfall ranging from 200 to 550 mm, the crop with SI and low nitrogen fertilizer gave 40% higher yields (**) than the farmers' conventional in-situ water harvesting system. Adding only SI or only low nitrogen did not result in significantly different yields. Accounting for actual ability of a storage system and SI to mitigate dry spells, it was estimated that a farmer would make economic returns (after deduction of household consumption) between year 2-7 after investment in dam construction depending on dam sealant and labour cost used. Simulating maize growth and site water balance in a system of maize with SI increased annual grain yield with 35 % as a result of timely applications of SI. Field water balance changes in actual evapotranspiration (ETa) and deep percolation were insignificant with SI, although the absolute amount of ETa increased with 30 mm y-1 for crop with SI compared to NI. The dam water balance showed 30% productive outtake as SI of harvested water. Large losses due to seepage and spill-flow occurred from the dam. Water productivity (WP, of ETa) for maize with SI was on average 1 796 m3 per ton grain, and for maize without SI 2 254 m3 per ton grain, i.e, a decerase of WP with 25%. The water harvesting system for supplemental irrigation of maize was shown to be both biophysically and economically viable. However, adoption by farmers will depend on other factors, including investment capacity, know-how and legislative possibilities. Viability of increased water harvesting implementation in a catchment scale needs to be assessed so that other down-stream uses of water remains uncompromised.

Water scarcity is a growing challenge in semi-arid and sub-humid areas. There are over 2000 small reservoirs (SRs) with storage capacities of up to 1 × 106 m3 across West Africa's dry areas. Based on a comprehensive literature review, we found strong evidence that SRs enable improved food security, livelihoods, and income diversification through fishing and livestock production. However, their productivity is far below their potential. Evidence on water quantity and quality is scattered, making deriving conclusions difficult. Review findings suggest that, unlike large dams, SRs have minimal impact on water balance and rainfall-runoff. There is, therefore, considerable potential to develop more SRs. However, high rates of sedimentation substantially reduce reservoir storage capacity. Poor irrigation management and agronomic practices also contribute to low productivity. Water quality is not systematically monitored, so SRs can increase health risks such as malaria and schistosomiasis. With the intensification of settlements, livestock, and agriculture around the reservoirs, it is critical to improve water quality and quantity monitoring. We conclude that SRs are important nature-based solutions, but need more investment to support the climate-proofing of agriculture and livelihoods. We recommend governments develop long-term small reservoir support programs to strengthen local capacities to manage the reservoirs and their watersheds sustainably.

Small reservoirs (SRs) are important infrastructures for providing water for a wide range of activities in Burkina Faso and other semiarid environments. In recent years, SRs have become even more important, considering the effects of climate change and variability such as erratic rainfall patterns, recurrent droughts and floods, delays in the onset of the rains (Laux et al. 2008), increased incidence of in-season dry spells (Lacombe et al. 2012), and high evapotranspiration rates. SRs provide vulnerable rural communities with water for multiple purposes, including domestic and agricultural uses (McCartney et al. 2012; Venot et al. 2012). However, a number of external factors are negatively influencing the sustainable uses of SRs. Rapid population growth (Zuberi and Thomas 2012) and its attendant human-induced activities are a threat to the quality of water in SRs, as are agricultural extensification and intensification around SRs, including the increased use of inorganic fertilizers. ; European Union ; International Fund for Agricultural Development ; Internal Review

Given the need for transformative changes towards more sustainable, integrated management of water, energy and food systems, the water-energy-food nexus concept seems highly relevant. However, while intuitively compelling, the nexus has also been criticized for abstracting and thereby dis-embedding the collaboration processes through which further integration could be achieved. There is a lack of empirical analysis and contextsensitive understanding, of the opportunities and constraints of, collaboration and cross-sector coordination, as faced by actors governing interconnected water, energy and food systems. In this paper we analyse how actors involved in the governance of water, energy and food systems are embedded in social networks, and discuss how that embeddedness shapes collaboration and coordination processes that are relevant for addressing interconnected sustainability challenges. Drawing on the notion of problemsheds, we delineate an analytical space that captures the interactions between water, energy and food systems and the actors influencing them in the Upper Blue Nile of Ethiopia. Our empirical data suggest that the claim that actors from different sectors are disconnected from each other is overly simplistic. The ways in which actors are embedded in hierarchical structures may help to explain why coordination challenges persist, despite the presence of cross-sectoral linkages among them.

Water scarcity is a growing challenge in semi-arid and sub-humid areas. There are over 2000 small reservoirs (SRs) with storage capacities of up to 1 x 10(6) m(3) across West Africa's dry areas. Based on a comprehensive literature review, we found strong evidence that SRs enable improved food security, livelihoods, and income diversification through fishing and livestock production. However, their productivity is far below their potential. Evidence on water quantity and quality is scattered, making deriving conclusions difficult. Review findings suggest that, unlike large dams, SRs have minimal impact on water balance and rainfall-runoff. There is, therefore, considerable potential to develop more SRs. However, high rates of sedimentation substantially reduce reservoir storage capacity. Poor irrigation management and agronomic practices also contribute to low productivity. Water quality is not systematically monitored, so SRs can increase health risks such as malaria and schistosomiasis. With the intensification of settlements, livestock, and agriculture around the reservoirs, it is critical to improve water quality and quantity monitoring. We conclude that SRs are important nature-based solutions, but need more investment to support the climate-proofing of agriculture and livelihoods. We recommend governments develop long-term small reservoir support programs to strengthen local capacities to manage the reservoirs and their watersheds sustainably.

Small reservoirs (SRs) are used for multiple purposes in Burkina Faso and West African agroecological landscapes (Venot et al. 2012). These SRs are used for domestic (drinking, bathing and washing) and agricultural (crop, livestock and fishery) purposes, among others (McCartney et al. 2012). However, natural processes and human-induced activities in the surrounding landscapes can be a threat to the water quality and sustainable use of SRs. In order to reduce negative effects, several projects have been designed to study different aspects of how SRs are used and impacted by natural and human-induced activities. But the number of SRs in Burkina Faso (about 1,450) (Cecchi et al. 2009) makes it practically impossible to study every single one of them. A possible solution to this is to categorize the SRs into groups in terms of their responses to the aforementioned natural and anthropogenic influences. Such categorization can provide the basis for site selection in subsequent research programs and further permit generalization (upscaling) of results obtained for selected SRs (at local scale) to many other SRs (at national scale). ; European Union ; International Fund for Agricultural Development ; Internal Review

Smallholder irrigation expansion would significantly increase agricultural production, and reduce food insecurity and poverty levels in East Africa. This paper reviews literature on trends, constraints and opportunities of smallholder irrigation in four East African countries: Ethiopia, Kenya, Tanzania and Uganda. Irrigation development has been slow in these countries, and has been mainly through traditional schemes. Recently, individual irrigation technologies such as small motorized pumps, drip kits, treadle pumps, rope and washer pumps are being promoted. Adoption of these technologies and expansion of smallholder irrigation however face a number of challenges including land tenure issues; lack of access to appropriate irrigation technologies, improved agricultural inputs, reliable markets, finance and credit services, and research support; poor transport and communication infrastructures; poor irrigation water management; poor extension systems; and the over dependence on national governments, NGOs and donors for support. Despite these challenges, opportunities exist for smallholder irrigation expansion in East Africa. Such opportunities include: high untapped irrigation potential; rainwater harvesting to improve water availability; high commitment of national governments, NGOs and donors to smallholder irrigation expansion; low cost irrigation technologies adaptable to local conditions; traditional schemes rehabilitation; growing urbanization; and increased use of mobile phones that can be used to disseminate information.

Land conversion in Sub-Saharan Africa has profound biophysical, ecological, political and social consequences for human wellbeing and ecosystems services. Understanding the process of land cover changes and transitions is essential for good ecosystem management policy that would lead to improved agricultural production, human wellbeing and ecosystems health. This study aimed to assess land cover transitions in a typical semi-arid degraded agro-ecosystems environment within the Pangani River Basin in northern Tanzania. Three Landsat images spanning over 30 years were used to detect random and systematic patterns of land cover transition in a landscape dominated by crop and livestock farming. Results revealed that current land cover transition is driven by a systematic process of change dominated by (i) transition from degraded land to sparse bushland (10.8%), (ii) conversion from sparse bushland to dense bushland in lowland areas (6.0%), (iii) conversion from bushland to forest (4.8%), and (iv) conversion from dense bushland to cropland in the highlands (4.5%). Agricultural lands under water harvesting technology adoption show a high degree of persistence (60-80%) between time slices. This suggests that there is a trend in land-use change towards vegetation improvement in the catchment with a continuous increase in the adoption of water harvesting technologies for crop and livestock farming. This can be interpreted as a sign of agricultural intensification and vegetation re-growth in the catchment.

A reliable supply of water is critical for agricultural intensification and yield improvement. Technological devices that lift, transport and apply water contribute to increased yield from improved crop varieties and high input cultivation. The increasing use of motor pumps is a significant contribution to the development of small-scale irrigation. The objective of this study was to identify and analyze the trajectories of technological innovations and uptake for agricultural water management in farming systems in Sri Lanka, with a special focus on identifying impacts, emerging issues and potential responses to the rapid proliferation of motor pumps in the intensification of agriculture in the country. The Government of Sri Lanka promoted the rapid adoption of water pumps through interventions such as the development of groundwater wells for agriculture; provision of subsidies and credit facilities for purchasing micro-irrigation equipment; and government policies on tax, tariffs and extension support. At the same time, the high profit margin realized from cash crop cultivation motivated farmers to invest in water lifting and related technologies. Finally, water scarcity and restrictions on the use of surface water, i.e., canals, prompted a shift to using water-lifting technologies to pump groundwater. The use of water pumps in agriculture has expanded the area under cultivation; increased cropping intensity, especially during the dry seasons; changed the cropping pattern from low-return rice cultivation to high-return cash crop cultivation; and enhanced household incomes. Expanded and intensified cultivation has provided more opportunities for women to participate in agriculture, generating additional income, and enhancing their purchasing power and decision-making at the household level. Some farmers do not have groundwater wells and water pumps because they lack the necessary capital to make the initial investment. Smallholder farmers, in particular, are reluctant to risk their limited income on new technologies. This may lead to the further marginalization of poor farmers. Inclusive intensification will require helping farmers to access irrigation technology, for example, through carefully targeted subsidies and access to credit. Using water pumps can provide benefits to both users and non-users, but uncontrolled groundwater extraction may also create new problems by putting enormous pressure on common property resources. The government will need to take on a dual role to both promote the inclusive growth of small-scale irrigation, and to prevent and mitigate its negative environmental impacts. This second role may include establishing a regulatory system, setting standards for well construction, and monitoring and enforcing standards on extraction and water quality. There is an urgent need for institutional measures and governance arrangements to guide and regulate groundwater irrigation, especially in the context of intensive cultivation using shallow aquifers.

In Uganda, upgrading smallholder agriculture is a necessary step to achieve the interlinked sustainable development goals of hunger eradication, poverty reduction and land degradation neutrality. However, targeting the right restoration practices and estimate their cost-benefit at the national scale is difficult given the highly contextual nature of restoration practices and the diversity of small-scale interventions to be adopted. By analysing the context-specific outcomes of 82 successful case studies on different Sustainable Land and Water Management (SLWM) in Uganda, we estimated that out-scaling of existing successful practices to 75% of agricultural land would require a one-time investment of US$ 4.4 billion from smallholders. Our results show that, besides the many social and environmental benefit commonly associated to SLWM, a wide outscale of SLWM could generate US$ 4.7 billion every year, once the practices are fully operational. Our context-specific estimates highlight the profitability of investing in smallholder farming to achieve the SDGs in Uganda, with geographical differences coming from specific social-ecological conditions. This study can guide sustainable intensification development by targeting the most suitable SLWM practices and plan for adequate financial support from government, investors and international development aids to smallholder farming.

The world's human population now constitutes the largest driving force of changes to the biosphere. Emerging water challenges require new ideas for governance and management of water resources in the context of rapid global change. This book presents a new approach to water resources, addressing global sustainability and focusing on socio-ecological resilience to changes. Topics covered include the risks of unexpected change, human impacts and dependence on global water, the prospects for feeding the world's population by 2050, and a pathway for the future. The book's innovative and integrated approach links green and blue freshwater with terrestrial and aquatic ecosystem functions and use. It also links changes arising from land-use alteration with the impacts of those changes on social-ecological systems and ecosystem services. This is an important, state-of-the-art resource for academic researchers and water resource professionals, and a key reference for graduate students studying water resource governance and management

peer-reviewed ; his article belongs to the Proceedings of TERRAenVISION 2019 ; Our planet suffers from humankind's impact on natural resources, biogeochemical cycles and ecosystems. Intensive modern agriculture with inappropriate inputs of fertilisers, pesticides and fossil fuel –based energy has increasingly added to human pressure on the environment. As a key element of our natural capital, soils are also under threat, despite being essential to provide food, feed, fibre and fuel for an increasing global population. Moreover, soils play a key role in carbon, water and energy cycles, highlighting their importance for biomass provision and the circular bioeconomy. Evidently, these new and complex challenges cannot be resolved effectively with existing knowledge and experience alone. These challenges require scientific research, interdisciplinary collaboration and networking to find context-specific and tailored solutions addressing societal issues of our time and facilitating the adoption of these solutions. The most effective approaches are based on the involvement of multiple actors from science, policy, economy, civil society and farming that have the same goal, work on the same societal issue, but have complementing backgrounds, expertise and perceptions. The European Joint Programme (EJP) SOIL is a European network of research institutes in the field of soil science and agricultural soil management that will provide science-based advice to practitioners and policymakers, at local, national and European level. The EJP SOIL aims to align and boost research, training and capacity building through joint programming activities co-funded by the European Commission and national research programs. This will reduce current fragmentation and help to find synergies in order to make a leapfrog in research on good agricultural soil management in three main areas: climate change mitigation and adaptation, production capacity in healthy food systems, and environmental sustainability. By joint programming, training and capacity building, EJP SOIL will also take into account the need for effective policy solutions, as well as the socio-economic conditions of all stakeholders in the agricultural value chain. Thus, a key focus of the EJP SOIL is to build and strengthen a framework for an integrated community of research groups working on related aspects of agricultural soil management. As part of this effort, EJP SOIL will co-construct with stakeholders a roadmap for agricultural soil research. To develop a structured roadmap, EJP SOIL works with a version of the knowledge management framework of Dalkir (2005). The EJP version uses four compartments: (i) Knowledge development, (ii) knowledge harmonisation, organisation and storage (iii) knowledge sharing and transfer, and (iv) knowledge application. The four segments are part of a cyclic process to enhance the development and use of knowledge on agricultural soils. Knowledge development comprises assessing new knowledge needs to achieve the expected impacts of EJP SOIL. Therefore, by involving multiple stakeholders, knowledge gaps across Europe will be identified to work towards the adoption of Climate-Smart Sustainable Agricultural Soil Management (CSSASM). Within the knowledge sharing and transfer compartment, the capacity of scientists, advisors, policy makers, farmers and other stakeholders will be strengthened. EJP SOIL will work to support networks and co-creation of new knowledge with stakeholder groups, stimulating innovation in CSSASM. The knowledge harmonization, organization and storage compartment of the knowledge framework ensures linkages with all stakeholders to guarantee data harmonization and standardization. The last compartment, application of knowledge, will be facilitated by creating better guidelines, awareness and capacity for Climate-Smart Sustainable Agricultural Soil Management adoption and by strengthening science-to-policy processes at EU and Member State level.