Cassava yield loss in farmer fields was mainly caused by low soil fertility and suboptimal management practices in two provinces of the Democratic Republic of Congo

Article purchasedA better understanding of the factors that contribute to low cassava yields in farmers’ fields is required to guide the formulation of cassava intensification programs. Using a boundary line approach, we analysed the contribution of soil fertility, pest and disease infestation and farmers’ cultivation practices to the cassava yield gap in Kongo Central (KC) and Tshopo (TSH) provinces of the Democratic Republic of Congo. Data were obtained by monitoring 42 and 37 farmer-managed cassava fields during two cropping cycles in KC and one cropping cycle in TSH, respectively. Each field was visited three times over the cassava growing period for the observations. Logistic model was fitted against the observed maximum cassava root yields and used to calculate the achievable yield per field and for individual factor. At field level, the factor that led to the lowest achievable yield (Yup(i)1) was considered as the dominant yield constraint. Cassava yield loss per field was expressed as the increase in the maximal root yield observed per province (Yatt- attainable yield) compared to Yup(i)1. Yatt was 21 and 24 t ha−1 in TSH and KC, respectively. With the cassava varieties that farmers are growing in the study areas, pests and diseases played a sparse role in the yield losses. Cassava mosaic was the only visible disease we observed and it was the dominant yield constraint in 3% and 12% of the fields in KC and TSH, respectively. The frequent yield constraints were suboptimal field management and low soil fertility. Cultivation practices and soil parameters led to Yup(i)1 in 47% and 50% of the fields in KC, and in 47% and 41% of those in TSH, respectively. Individual soil parameters were the yield constraint in few fields, suggesting that large-scale programs in terms of lime application or recommendation of the blanket fertilisers would result in sparse efficacy. In KC, yield losses caused by low soil fertility averaged 6.2 t ha−1 and were higher than those caused by suboptimal field management (5.5 t ha−1); almost nil for cassava mosaic disease (CMD). In TSH, yield losses caused by low soil fertility (4.5 t ha−1) were lower than those caused by suboptimal field management (6.5 t ha−1) and CMD (6.1 t ha−1). Irrespective of the constraint type, yield loss per field was up to 48% and 64% of the Yatt in KC and TSH, respectively. Scenario analysis indicated that the yield losses would remain at about two third of these levels while the dominant constraint was only overcome. We concluded that integrated and site-specific management practices are needed to close the cassava yield gap and maximize the efficacy of cassava intensification programs

Connecting climate action with other sustainable development goals

The international community has committed to combat climate change and achieve 17 Sustainable Development Goals (SDGs). Here we explore (dis)connections in evidence and governance between these commitments. Our structured evidence review suggests that climate change can undermine 16 SDGs, while combatting climate change can reinforce all 17 SDGs but undermine efforts to achieve 12. Understanding these relationships requires wider and deeper interdisciplinary collaboration. Climate change and sustainable development governance should be better connected to maximize the effectiveness of action in both domains. The emergence around the world of new coordinating institutions and sustainable development planning represents promising progress

A review of the water-energy-food nexus research in Africa

Notwithstanding the dispersed nature of the water, energy and food (WEF) nexus scholarship in the African continent, its strategic importance to the African agenda has gained widespread attention in research and planning circles. In this regard, the bibliometric science mapping and content analysis of the WEF nexus scientific publication trends, the conceptual, intellectual and social structures, as well as the inherent paradigmatic shifts in the WEF nexus body of knowledge in the African continent have been undertaken, using the nexus body of literature accessed from the Web of Science and Scopus core collection databases. The review results confirmed that, whilst the WEF nexus scholarship has expanded since 2013, there is also evidence of growth in the conceptual, intellectual and social structures of the WEF nexus in the African continent. These shifts have resulted in the emergence of hot topics (subfields) including modelling and optimization, climate variability and change, environmental ecosystem services sustainability, and sustainable development and livelihoods. The review further determined that these structures have evolved along two main perspectives of WEF nexus research development, i.e., the interdisciplinary and transdisciplinary domains. In support of the interpretation of the visual analytics of the intellectual structure and changing patterns of the WEF nexus research, the shifts in positivist, interpretivist and pragmatic paradigmatic perspectives (these are underpinned by the ontology, epistemology, and methodology and methods) are considered when explaining WEF nexus research shifts: (a) From the unconnected silo paradigms that focus on water, energy and food (security concerns) to interconnected (and sometimes interdependent or nested) linkages or systems incorporating environmental, social-economic and political drivers (also viewed as subfields) in a bid to holistically support the Sustainable Development Goals (SDGs) across the African continent; and (b) in the evaluation of the WEF nexus scholarship based on novel analytical approaches. We contend that whilst the theories of science change underpin this apparent expansion, the macro-economic theory will find use in explaining how the WEF nexus research agenda is negotiated and the Integrative Environmental Governance (IEG) is the duly suited governance theory to bridge the inherent disconnect between WEF nexus output and governance processes uncovered in the literature. Overall, operational challenges and opportunities of the WEF nexus abound, transitioning the WEF nexus research to practice in Africa, motivating the need to take advantage of the scholar–practitioner research underpinnings, as contemplated in the transdisciplinary research approach, which is characterised by the dual quest for new knowledge and considerations of use. Yet, there is need for more coordinated and collaborative research to achieve impact and transition from WEF nexus thinking to WEF nexus practice.The Water Research Commission of South Africa. The APC was funded by the University of KwaZulu-Natal’s Centre for Transformative Agricultural and Food Systems.https://www.mdpi.com/journal/sustainabilitydm2022Geography, Geoinformatics and MeteorologySchool of Health Systems and Public Health (SHSPH

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

Obstacles to local-level AIDS competence in rural Zimbabwe: putting HIV prevention in context

We explore the wider social context of an HIV-prevention programme in rural Zimbabwe. We make no comment on the programme itself, rather seeking to examine the wider community dynamics into which it was inserted, to highlight how pre-existing social dynamics may have influenced community readiness to derive optimal benefit from the intervention. Using the concept of the AIDS competent community, we analysed 44 interviews and 11 focus groups with local people. Despite high levels of HIV/AIDS-related knowledge, there were several ways gender, poverty and low literacy may have undermined its perceived relevance to peoples' lives. Lack of opportunities for dialogue in the social milieu beyond the intervention may have limited opportunities for translating factual AIDS knowledge into action plans, or sharing hidden individual experiences of HIV/AIDS-affected family members or friends, given stigma and denial. The initiative of women and young people to respond effectively to AIDS was limited in a context dominated by adult males. People spoke of HIV/AIDS in a passive and fatalistic way, expecting outsiders to solve the problem. This tendency was exacerbated given the community's previous experiences of HIV/AIDS-related NGOs, which had often regarded local people as unpaid volunteer labour rather than building their capacity to make significant decisions and play leadership roles in health programmes. Despite obstacles, however, there were many potential community strengths and resources. There were high levels of HIV/AIDS-related knowledge. Public denial of HIV/AIDS masked huge reservoirs of private support and kindness to AIDS-affected family and friends. There were many strong community organisations and clubs, potentially forming the springboard for more empowered community responses to HIV/AIDS. HIV/AIDS programmers should pay greater attention to community readiness for interventions, especially around: (1) identifying and anticipating pre-existing obstacles to programme success and (2) mobilising the social assets that exist, even in contexts of poverty and gender inequality. This article is made available in full text via the publishers website