Assessing Long-Term Trends In Vegetation Productivity Change Over the Bani River Basin in Mali (West Africa)

Using time series of Normalized Difference Vegetation Index (NDVI) and rainfall data, we investigated historical vegetation productivity trends from 1982 to 2011 over the Bani River Basin in Mali. Statistical agreements between long-term trends in vegetation productivty, corresponding rainfall and rate of land cover change from Landsat time-series imagery was used to discern climate versus human-induced vegetation cover change. Spearman correlation was used to investigate the relationship between metrics of vegetation, rainfall trends and land cover change categories. The results show there is a positive correlation between increases in rainfall and some land cover classes, while some classes such as settlements were negatively correlated with vegetation productivity trends. Croplands and Natural Vegetation were positively correlated (r=0.89) with rainfall while settlements have a negative correlation with NDVI time series trend (r=-057). Despite the fact that rainfall is the major determinant of vegetation cover dynamics in the study area, it appears that other human-induced factors such as urbanization have negatively influenced the change in vegetation cover in the study area. The results show that a combined analysis of NDVI, rainfall and spatially explicit land cover change provides a comprehensive insight into the drivers of vegetation cover change in semi-arid Africa

Assessing the inter-relationship between vegetation productivity, rainfall, population and land cover over the Bani River Basin in Mali (West Africa)

This research investigated the inter-relationship between vegetation productivity, measured using the Normalized Difference Vegetation Index (NDVI), change in rainfall and population density in the context of perceived greening and degradation trends over the Bani River Basin (BRB). A 30-year (1982-2011), 8-km gridded rainfall data sets was produced by inverse distance weighted (IDW) interpolation of monthly data from 40 meteorological stations contained within the basin. Population data were retrieved from the National Population Statistic data base for 1987, 1997, and 2009. Rainfall and NDVI time-series trends were computed for the 30-year period and analysed. The relationship between rainfall and NDVI at pixel level, and NDVI and population densities was analysed using a Pearson correlation. Land Use and Land Cover (LULC) conversion rates were computed for the same period using multi-temporal 30-meter Landsat imagery; ground surveys for selected areas within the basin were used for further cross-verification. The computed NDVI trends revealed that, vegetation 'greening' trends are mostly associated with areas where natural vegetation is still well represented. Concurrent with increases in rainfall over the period analysed, this finding supports the hypothesis that re-greening observed in that area is the result of multi-decadal fluctuations in climate, rather than improved land management

Multi-scale governance in agriculture systems: Interplay between national and local institutions around the production dimension of food security in Mali

Enforcement of rules and laws designed at the national level is still one of the dominant institutional mechanisms for effective multiscale governance in most countries. At times, such blanket regulations are not only unable to meet practical needs at local levels, but they may conflict with local institutional logics, thereby creating new challenges. This study looks at three institutional arrangements in the agriculture and food security sector in the district of Koutiala, Mali to analyse the institutional variety across scale and the underlying institutional logics. On one side, the Cooperative Law as well as the Seed Law both designed at national level to enable famers’ access to agriculture services and improved seeds have yielded mixed results with regard to anticipated outcomes. The cooperative law is believed to degrade the social cohesion and the mutual support on which vulnerable farmers rely when facing climatic and non-climatic risks whereas the new seed system is found onerous and unaffordable for farmers. On the other side, the local convention for the management of natural resources established as part of ongoing decentralised governance policy seems to resonate with local culture but challenged by other stakeholders. Through exploring these cases, this paper tests bricolage as an analytical framework for doing an institutional diagnostic. It aims at contributing to methodological and theoretical insights on the way sustainable institutions can be generated in conflicting institutional logics in the context of multi-scale governance

Modeling of sorghum response to photoperiod: a threshold-hyperbolic approach

High photoperiod sensitivity is a singular trait for adaptation of sorghum to environmental constraints in sudano-sahelian West Africa. Difficulties encountered by selected models such as CERES-sorghum and STICS to simulate crop development may result from the representation of sorghum response to daylength during the photoperiod inductive phase. Four modeling approaches combining two temperature and photoperiod responses (linear, hyperbolic) and two calculation methods for development rates (cumulative, threshold) were evaluated to simulate time to panicle initiation (PI) in highly photoperiod sensitive Guinea sorghum variety CSM388. In the cumulative method, development rates were computed as summations of daily photothermal ratios, whereas in the threshold method accumulated degree days were tested against thermal time requirement to PI modulated by current photoperiod. Each model was calibrated based on observations from a Sotuba, Mali (12°39′N) planting date experiment spanning a 2-month period in 1996. Observed time from emergence to PI decreased from 54 to 22 days for a 20 min variation in daylength. Apparent higher performance by threshold methods was further tested against a 1994 independent dataset featuring three latitudes and a much wider range of sowing dates extending from February to September. Results validate the superiority of threshold over cumulative methods and confirm the better fit of a hyperbolic temperature and photoperiod response. A threshold-hyperbolic modeling approach is believed to be more consistent with crop physiology as it associates cumulative (temperature) processes and trigger (photoperiod) events that better reflect the concepts of quantitative plant growth and qualitative plant development. Its mathematical form and computational simplicity should ensure wide applicability for varietal screening over a large range of photoperiod sensitivities including neutral cultivars, and easy implementation into existing models

Do participatory scenario exercises promote systems thinking and build consensus?

Participatory scenario processes are associated with positive social learning outcomes, including consensus-building and shifts toward more systemic thinking. However, these claims have not been assessed quantitatively in diverse cultural and socio-ecological settings. We convened three stakeholder workshops around the future of agricultural development and rural livelihoods in Burkina Faso, Nigeria, and Malawi, using a participatory scenario generation process to examine proposed research and action priorities under conditions of uncertainty. We administered pre- and post-workshop surveys, and used a paired t-test to assess how stakeholders’ rankings of research priorities changed after participating in the scenario visioning exercise. Workshop participants also listed their own priorities for research and implementation on both the pre- and post-survey forms. We found indications that the workshops promoted consensus-building around the research priorities, including a reduction in standard deviation of priority rankings post-workshop compared to pre-workshop; and a higher incidence of identical volunteered responses. We did not find evidence to support shifts in thinking to more systemic views of agricultural development. However, participants viewed themselves as having learned throughout the process. We conclude that scenario visioning does have the potential to foster consensus-building (one element of social learning) among diverse stakeholder groups. We urge researchers to continue to monitor and measure systems thinking outcomes from scenario visioning so that these processes may be designed to be more effective

Estimating smallholder crops production at village level from Sentinel-2 time series in Mali's cotton belt

In Mali's cotton belt, spatial variability in management practices, soil fertility and rainfall strongly impact crop productivity and the livelihoods of smallholder farmers. To identify crop growth conditions and hence improve food security, accurate assessment of local crop production is key. However, production estimates in heterogeneous smallholder farming systems often rely on labor-intensive surveys that are not easily scalable, nor exhaustive. Recent advances in high-resolution earth observation (EO) open up new possibilities to work in heterogeneous smallholder systems. This paper develops a method to estimate individual crop production at farm-to-community scales using high-resolution Sentinel-2 time series and ground data in the commune of Koningue, Mali. Our estimation of agricultural production relies on (i) a supervised, pixel-based crop type classification inside an existing cropland mask, (ii) a comparison of yield estimators based on spectral indices and derived leaf area index (LAI), and (iii) a Monte Carlo approach combining the resulting unbiased crop area estimate and the uncertainty on the associated yield estimate. Results show that crop types can be mapped from Sentinel-2 data with 80% overall accuracy (OA), with best performances observed for cotton (Fscore 94%), maize (88%) and millet (83%), while peanut (71%) and sorghum (46%) achieve less. Incorporation of parcel limits extracted from very high-resolution imagery is shown to increase OA to 85%. Obtained through inverse radiative transfer modeling, Sen2-Agri estimates of LAI achieve better prediction of final grain yield than various vegetation indices, reaching R2 of 0.68, 0.62, 0.8 and 0.48 for cotton, maize, millet and sorghum respectively. The uncertainty of Monte Carlo production estimates does not exceed 0.3% of the total production for each crop type

Impact of Acute Malaria on Pre-Existing Antibodies to Viral and Vaccine Antigens in Mice and Humans

Vaccine-induced immunity depends on long-lived plasma cells (LLPCs) that maintain antibody levels. A recent mouse study showed that Plasmodium chaubaudi infection reduced pre-existing influenza-specific antibodies--raising concerns that malaria may compromise pre-existing vaccine responses. We extended these findings to P. yoelii infection, observing decreases in antibodies to model antigens in inbred mice and to influenza in outbred mice, associated with LLPC depletion and increased susceptibility to influenza rechallenge. We investigated the implications of these findings in Malian children by measuring vaccine-specific IgG (tetanus, measles, hepatitis B) before and after the malaria-free 6-month dry season, 10 days after the first malaria episode of the malaria season, and after the subsequent dry season. On average, vaccine-specific IgG did not decrease following acute malaria. However, in some children malaria was associated with an accelerated decline in vaccine-specific IgG, underscoring the need to further investigate the impact of malaria on pre-existing vaccine-specific antibodies

Potential benefits of drought and heat tolerance and yield enhancing traits in Sorghum with climate change at selected sites in India and West, Socioeconomics Discussion Paper Series Number 4

Climate change will alter growing conditions of sorghum crop in semi-arid tropical areas of the world. This will require developing high yielding cultivars that are able to perform better under drought and heat stress and with maturity durations to match the water availability period of target sites. The CSM-CERES-Sorghum model was used to quantify the potential benefits, in current and future climates, of incorporating crop maturity duration, yield enhancing, drought and heat tolerance traits in the commonly grown cultivar types at two sites (Akola and Indore) in India and one site (Samanko) in Mali, West Africa. Decreasing crop maturity duration by 10% decreased yields at all the three sites. Whereas, increasing crop maturity by 10% increased yield up to 12% at Akola and 9% each at Indore and Samanko. Increasing yield potential of the baseline, short and longer duration cultivars by increasing RUE (radiation use efficiency), G1 (scale for relative leaf size) and G2 (scale for partitioning of assimilates to the panicle) coefficients increased the grain yield to varying degree. This yield increase for the longer duration cultivar was 11 to 18% at Akola, 17 to 19% at Indore and 6 to 7% at Samanko in current and future climates of the sites. At the three sites the yield gains were larger by incorporating drought tolerance than heat tolerance trait in current climate, however, with climate change the yield gains due to heat tolerance increased trait increased especially at the Akola site. Net benefit of incorporating both drought and heat tolerance traits increased up to 17% at Akola, 9% at Indore and 7% at Samanko with climate change. It is concluded from this study that different combination of traits will be needed to increase and sustain productivity of sorghum in current and future agro-climates of the target sites and that the CSM-CERES-Sorghum model for sorghum can be used to quantify benefits of incorporating such plant traits

Farming with current and future climate risk: Advancing a 'Hypothesis of Hope' for rainfed agriculture in the semi-arid tropics

Climate change predictions point to a wanner world within the next 50 years, a trend that is increasingly being supported by 'on-the-ground' measurements. However, the impact of rising temperatures on rainfall distribution patterns in the semi-arid tropics (SAT) of Africa and Asia remains far less certain. During 2008, ICRISA T's crop modelers, GIS experts, crop physiologists and plant breeders met in Hyderabad, India for one week. Using a range of weather data driven tools, they initiated research to test the hypothesis that "in the medium term (2010-2050). ICRISAT is well placed to help farmers mitigate the challenges and exploit the opportunities that are posed by climate change through: (i) the application of existing knowledge on crop. soil and water management innovations, and (ii) the re-deployment and re-targeting of the existing germ plasm of its mandate crops." Rather than selecting specific climate change scenarios, we chose to undertake a 'sensitivity-based' analysis in which we looked at the impact of a factorial combination of climate change of5 different temperature increases (I, 2, 3, 4 and 5°C) and 3 different percentage changes in seasonal rainfall (0%, + I 0% and -10%) and compared the outputs with a 'control' of the current climate at each location for which the analyses was undertaken. We undertook three types of analyses. Firstly, we looked at the implication of these climate change combinations for changes in the length of growing period (LGP) and how they might effect the global distribution and extent of the SAT. Secondly, we examined in some detail how these scenarios would impact on crop production (millet, sorghum, groundnut and pigeonpea) in eastern, southern and western Africa and in India. We also looked, albeit to a lesser extent, at the potential 'fertilizer effect' of enhanced CO2 levels on crop production. Finally, we examined the potential of improved production practices and better adapted germplasm to mitigate the impact of climate change

Increasing the productivity of sorghum farmers in the Sudan Savannah of Nigeria: Effect of access to improved technology and market

Sorghum has assumed greater importance in the economies of several African countries especially with the renewed interest by processors who are interested in using the grain to compliment/substitute wheat and barley in the confectionery and malting industries. Low on-farm grain yields are attributed to low use of inputs including seeds and fertilizers as well as good agronomic practices. ICRISAT Nigeria, in collaboration with several partners under the Agricultural Transformation Support Project (ATASP-1) implemented several activities including thematic training, on-farm technology demonstrations, community seed production and formation of innovation platforms (IPs) for market linkages. Remarkable progress were made in enhancing access to quality seeds and other inputs to over 40,000 farmers while expanding knowledge of Improved technologies to over 100 communities. During the 2016 cropping season, farmers produced over 70,268 Mt of grains valued at N9.135billion (US$29M). The impacts of trainings resulted in about 60% improvement in the understanding of good agronomic practices and post-harvest handling by the farmers and extension agents. The use of improved technologies increased grain yields by 30 to 64% (improved varieties), 27 to 38% (seed dressing), and 20% to 55% (tillage practices). Through IPs and market linkages to large scale processors, 109.76 tons of seeds were procured, distributed and planted. Average yield obtained from improved technologies was 1.5 t/ha compared to 1.1 t/ha by other farmers giving a 40% increase. A total of 1,093 women farmers comprising of about 34.2% of the total number of participating farmers benefited directly from the project. Seed fairs, radios and audio-visual broadcasts on improved production technologies and market availability were used to reach non-participating farmers within the zones. The combination of methods stimulated adoption of improved sorghum production technologies and market linkages proofed effective in achieving both increased sorghum yields and household income