| 1. |
- Enfors, Elin, 1978-, et al.
(author)
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Dryspell frequency and trends over time in semi-arid and dry sub-humid sub-Saharan Africa : Implictions for smallholder farmers
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Other publication (other academic/artistic)abstract
- Small-scale farmers in semi-arid and dry sub-humid sub-Saharan Africa (SSA) are vulnerable to dryspells, a primary reason for agricultural droughts. We used large-scale publicly available datasets to analyze frequency and trends over time in dryspells of critical length for farmers. 54 rainfall stations across the croplands of semi-arid and dry sub-humid SSA were included. Results show that stations with long-term seasonal rainfall averages below 600 mm experience critical dryspells in more than 60% of their seasons, whereas the corresponding figure for stations with averages above 600 mm is 40% or less. Almost every season is affected by dryspells for stations below 400 mm. Further, dryspell seasons are often affected by multiple dryspells. Most stations do not show any trends of changing dryspell frequency. Among the 21 stations that do exhibit changes over time, 19 have been subjected to an increasing trend, and only 2 to a decreasing trend. For six stations the increase is statistically significant. We conclude that frequent dryspell seasons with multiple dryspells, is a reality of rainfed farming systems, especially in semi-arid SSA. Efforts to increase productivity in these systems must include strategies to manage dryspells to be effective. The publicly available data contains large gaps that restrict the analysis. This is highly problematic, particularly given the fundamental importance of rainfall dynamics for livelihoods in the poorest regions of the world.
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| 2. |
- Enfors, Elin, 1978-
(author)
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Traps and transformations : Exploring the potential of water system innovations in dryland sub-Saharan Africa
- 2009
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Doctoral thesis (other academic/artistic)abstract
- In semi-arid and dry sub-humid sub-Saharan Africa (SSA), high poverty levels and a heavy reliance on small-scale rainfed agriculture make rural livelihoods difficult. Upgrading current farming systems, in a way that safeguards productivity beyond field-scale, is urgent. This thesis builds on a case study of the Makanya catchment in Tanzania, and focuses on the potential of small-scale water system innovations (SWSIs), such as rainwater harvesting and conservation tillage, for increasing on-farm productivity while supporting multi-functional landscapes. The thesis consists of five papers that approach questions of alternative development trajectories for smallholder agro-ecosystems, and effects of SWSIs on key system variables, from varying perspectives. Paper I presents a conceptual model for interpreting multi-equilibrium dynamics in dryland agro-ecosystems, and analyzes Makanya's development over the past 50 years. Paper II investigates farmers' strategies to deal with drought and the impact of a local supplemental irrigation system on coping capacity. Paper III studies the effects of conservation tillage on yields and soil properties. Paper IV explores a set of future scenarios for the catchment. Paper V maps dryspell frequency and trends over time in a drylands-in-SSA perspective. The results show that smallholder farmers in agro-ecosystems such as Makanya depend on a wide array of on- and off-farm ecosystem services. The productivity of the surrounding landscape is especially important when crops fail. Furthermore, dryspells are a major constraint in these systems. In Makanya long dry-spells have become twice as common over the past 50 years, and frequently cause crop failures. This is a driver for land degradation, and maintains a climate-related poverty trap. SWSIs provide opportunities for dryland farmers to shift their agro-ecosystems to more productive trajectories through a number of mechanisms, including lowered crop failure frequency, altered on-farm water balances, and improved soil quality. Although this is promising, the task of transforming these systems is complex. For SWSIs to be effective, prerequisites are farming system solutions that integrate water- and nutrient management, and broad-based investments that focus on a much wider range of issues than only the water management technology. Moreover, given the uncertain future, investments in small-scale farming should be designed so that they benefit local communities across a range of pathways. Participatory scenario planning is useful both for identifying robust investment strategies and for navigating towards desirable development trajectories.
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| 3. |
- Enfors, Elin, 1978-, et al.
(author)
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Yield and soil system changes from conservation tillage in dryland farming : A case study from North Eastern Tanzania
- 2011
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In: Agricultural Water Management. - : Elsevier BV. - 0378-3774 .- 1873-2283. ; 98:11, s. 1687-1695
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Journal article (peer-reviewed)abstract
- Yield levels in smallholder farming systems in semi-arid sub-Saharan Africa are generally low. Water shortage in the root zone during critical crop development stages is a fundamental constraining factor. While there is ample evidence to show that conservation tillage can promote soil health, it has recently been suggested that the main benefit in semi-arid farming systems may in fact be an in situ water harvesting effect. In this paper we present the result from an on-farm conservation tillage experiment (combining ripping with mulch and manure application) that was carried out in northeastern Tanzania from 2005 to 2008, testing this hypothesis. Special attention was given to the effects on the water retention properties of the soil. The tested conservation treatment only had a clear yield increasing effect during one of the six experimental seasons (maize grain yields increased by 41%, and biomass by 65%), and this was a season that received exceptional amounts of rainfall (549 mm). While the other seasons provided mixed results, there seemed to be an increasing yield gap between the conservation tillage treatment and the control towards the end of the experiment. Regarding soil system changes, small but significant effects on chemical and microbiological properties, but not on physical properties, were observed. This raises questions about the suggested water harvesting effect and its potential to contribute to stabilized yield levels under semi-arid conditions. We conclude that, at least in a shorter time perspective, the tested type of conservation tillage seems to boost productivity during already good seasons, rather than stabilize harvests during poor rainfall seasons. Highlighting the challenges involved in upgrading these farming systems, we discuss the potential contribution of conservation tillage towards improved water availability in the crop root zone in a longer-term perspective.
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| 4. |
- Meacham, Megan, 1986-, et al.
(author)
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Advancing research on ecosystem service bundles for comparative assessments and synthesis
- 2022
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In: Ecosystems and People. - : Informa UK Limited. - 2639-5908 .- 2639-5916. ; 18:1, s. 99-111
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Journal article (peer-reviewed)abstract
- Social-ecological interactions have been shown to generate interrelated and reoccurring sets of ecosystem services, also known as ecosystem service bundles. Given the potential utility of the bundles concept, along with the recent surge in interest it is timely to reflect on the concept, its current use and potential for the future. Based on our ecosystem service bundle experience, expertise, and ecosystem service bundle analyses, we have found critical elements for advancing the utility of ecosystem service bundle concept and deepening its impact in the future. In this paper we 1) examine the different conceptualizations of the ecosystem service bundle concept; 2) show the range of benefits of using a bundles approach; 3) explore key issues for improving research on ecosystem service bundles, including indicators, scale, and drivers and relationships between ecosystem services; and 4) outline priorities for the future by facilitating comparisons of ecosystem service bundle research.
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