Browsing by Subject "Madagaskar"

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Agrofuels, large-scale agricultural production, and rural development : the case of Jatropha in Madagascar
(2019) Bosch, Christine; Zeller, Manfred
Agrofuel production in marginal areas can contribute directly to creating employment and improving local livelihoods. Indirectly, through increasing household purchasing power and relaxing financial constraints of smallholder farmers, it can contribute to greater food production and/or food consumption and rural development. These benefits depend, however, largely on the feedstock crop and its processing, land and labour requirements, the business model, value chains and institutional frameworks. Jatropha, a feedstock crop with more benefits than first-generation energy crops like maize, experienced a spike in popularity in the early 2000s due to its value in the biofuel markets of industrialized countries. The majority of plantations and outgrower schemes could not survive what followed: disappointing yields, pests and disease, low oil prices, the 2007/2008 food price crisis, negative narratives, and inadequate funding for further research activities. Despite these challenges, large-scale land investments and new Jatropha projects continue to be undertaken. Madagascar is a country characterized by severely eroded and degraded pasturelands, low agricultural productivity, high vulnerability to climatic shocks, and overwhelming poverty and food insecurity rates. It is hypothesized that the use of marginal lands for labour-intensive agrofuel feedstock cultivation, in otherwise neglected areas, through both public and private investment, will have positive impacts through the provision of wage work in large-scale plantation schemes. Although a number of studies have investigated the rural livelihood impacts of participation in Jatropha cultivation, there is little evidence that quantifies the long-term and indirect effects on smallholder food production and household food security. Against this background, large-scale Jatropha cultivation lends itself well to studying the complex interplay between feedstock and food production, as well as the potential for agricultural and rural development. Such analysis would provide useful insights and implications for cost-effective rural development policies to target poor farmers in remote areas. Drawing on a conceptual framework that highlights the role of smallholder farmers’ livelihood strategies like off-farm employment and agricultural intensification, and livelihood outcomes like food security, this thesis explores the contribution of large-scale agrofuel feedstock cultivation on marginal land. Three important outcomes, namely household food security, information and innovation spillover effects, and agricultural input use, are studied empirically in three articles, using a comprehensive household panel data set. The data was collected in six survey rounds between 2008 and 2014, in three villages near a large-scale Jatropha project in the Haute Matsiatra region, located in Madagascar’s Southern Highlands. The first article examines the relationship between wage work for a Jatropha project and household food security. Jatropha cultivation on marginal land is labour intensive and does not compete with food production. Therefore, incomes earned can contribute to increased food security directly as well as indirectly through increased or diversified food production. Using five rounds of household panel data, results show that labour demand from the plantation declined substantially after the build-up phase and Jatropha incomes were mostly used for food and other necessities. Fixed effects models show that Jatropha work contributed significantly to an improved dietary diversity. Despite the possibility to earn income during the lean season, Jatropha work did not lead to a reduction in the more subjective lack of food and led to reduced rice stocks. Both food production and consumption were highly influenced by drought shocks and locust plagues, indicating that complementing income creation strategies with agricultural development strategies might have further positive effects on food security. To shed light on the impact pathway from Jatropha work to agricultural production, the second article explores information dissemination through social networks and through Jatropha workers who are more exposed to modern technologies than control households. In addition to institutional factors, a lack of knowledge and limited extension services for improved agricultural technologies are considered barriers to information dissemination. Using two rounds of the dataset, which contains rich information on social capital and networks as well as knowledge and innovations, determinants of production-relevant knowledge like extension services, credit and marketing opportunities are estimated. Accounting for potential endogeneity with lagged and instrumental variables, the relevance of this knowledge to the adoption of innovations and the cultivation of a formerly taboo legume, as an example of diversification, is tested. The results indicate limited access to information, little knowledge on investment and marketing opportunities, and low adoption of innovations. Knowledge is relevant for both innovation performance and the cultivation of the Bambara groundnut, highlighting the need to increase and improve public extension services and information dissemination in rural Madagascar. Adoption is not only encouraged by knowledge, but also directly motivated through informal social networks. Bambara groundnut spillovers from the biofuel project can be observed, relaxing some of the constraints farmers face concerning access to information, social learning, and cultural norms. The third article explores one specific hypothesized spillover: access to and use of agricultural inputs. Given the very low use of improved inputs in rural areas in Madagascar, this study explores whether improved seed and seed information distributed to farmers encourages farmers to cultivate the seed. The analysis is based on household data gathered between 2012 and 2014 from 390 households in three villages. To investigate the adoption of improved seed, as well as the diffusion of information regarding improved seed, a randomized control trial was applied in 2013. Half of the 390 households were randomly assigned to receive the improved lima bean seed (Phaseolus lunatus), which is specifically bred for dry regions. Of the seed-receiving households, half were randomly assigned to receive information on how to store, plant, and cultivate the improved seed, as the variety was unfamiliar in the region. The control group and the two treatment groups are compared with respect to baseline characteristics, bean cultivation, information exchange with other farmers, legume consumption, and willingness to pay (WTP) for improved bean seed. To account for non-compliance, contamination, and spillover effects, local average treatment effects (LATE) are estimated. Of the seed-receiving households, 54% cultivated the seed, reaping an average yield of 6.3 kg for each kilogram of seed obtained. Seed information did not lead to higher yields. A small significant positive impact of seed distribution on legume consumption is found. WTP is 171% of the local market price for bean seed; provision of free seeds and information did not result in a higher WTP. Based on these findings, this thesis contributes empirical evidence that large-scale agrofuel feedstock production on marginal land can enhance rural livelihoods by offering alternative livelihood strategies especially for poorer households and contributing to improved livelihood outcomes. Accounting for the indirect effects shows important impact pathways on the livelihood strategies of farmers in a remote area. The provision of incentives for private investors, complemented by more public intervention in rural areas, as well as more investment in agricultural research and extension to reduce agricultural production risks, might enhance these spillovers.
Physiological and growth responses of Jatropha curca L. to water, nitrogen and salt stresses
(2012) Rajaona, Arisoa Mampionona; Asch, Folkard
This thesis provides necessary and complementary information for an improved understanding of jatropha growth to guide further research to evaluate the response of jatropha to abiotic stressors and for designing plantations adapted to the plants? requirements. Given the fact that jatropha is claimed to grow on marginal lands, we studied effects of water supply, salt stress, nitrogen and air humidity as major abiotic stressors on gas exchange parameters and biomass production followed by management options for pruning the trees to positively influence biomass productivity and to contribute to optimize resource use. The effects of water availability (rainfed versus irrigated) on growth and gas exchange parameters were investigated for 4-year old jatropha grown in a semi-arid environment at a plantation site in Madagascar in 2010. The results confirmed that 1250 mm water in addition to a 500 mm rainfall did not affect biomass production and instantaneous gas exchange. Nevertheless, leaf light responses of irrigated plants were higher than that of rainfed plants. The study showed to what extent salt stress affected water use, canopy water vapour conductance, leaf growth and Na and K concentrations of leaves of 3-year old and young jatropha plants. 3-year old plants were exposed to seven salt levels (0-300 mmol NaCl L-1) during 20 days and young plants to five salt levels (0-200 mmol NaCl L-1) during 6 days. In both experiments, plants responded rapidly to salt stress by reducing water loss. The threshold value of responses was between 0 and 5 dS m-1. Leaf area increment of young jatropha had a threshold value of 5 dS m-1 implying that jatropha is sensitive to external salt application in terms of canopy development, conductance and CO2 assimilation rate. Transpiration of plants in both experiments was reduced to 55% at EC values between 11 and 12 dS m-1 as compared to non-stressed plants. These findings indicate that jatropha responds sensitive to salt stress in terms of leaf elongation rate and consequently canopy development, and to immediate physiological responses. Leaf gas exchange characteristics of jatropha as affected by nitrogen supply and leaf age were intensively studied, as carbon assimilation is one of the central processes of plant growth and consequently a key process embedded in modelling approaches of plant productivity. This study showed that N supply effects on leaf gas exchange of jatropha leaves were small with only the treatment without nitrogen resulting in lower rates of CO2 assimilation rate and light saturated CO2 assimilation rate, nevertheless, effects of N supply on biomass formation were pronounced. Instantaneous rates of leaf gas exchange of different leaves subject to variable air humidity (atmospheric vapour pressure deficit (VPD)) were investigated. This study showed that CO2 assimilation rate (A) and stomatal conductance (gs) were correlated in a hyperbolic fashion, and that gs declined with increasing VPD. Maximal stomatal conductance of jatropha was in the range of 382 mmol m-2 s-1 and gs is predicted to be close to zero at 6 kPa. Effects of VPD, via stomatal conductance, by preventing high transpiration rates, have been demonstrated to be decisive on water use efficiency. Our findings are in this regard relevant for the estimation of water use efficiency of jatropha. The outcome further indicates favourable conditions at which stomatal opening is high and thereby allowing for biomass formation. This information should be considered in approaches which aim at quantifying leaf activity of field-grown bushes which are characterized by spatially highly diverse conditions in terms of microclimatic parameters. Microclimatic parameters can be modified by the tree structure. The reported field experiment on 4-year old jatropha indicated that the biomass production and canopy size depended mainly on primary branch length. A comparison of plants of different pruning types with regard to trunk height (43 versus 29 cm) and total length of primary branches (171 versus 310 cm), suggest that higher biomass production and greater leaf area projection was realized by trees with short trunks and long primary branches. Growth of twigs and leaves was positively correlated with total length of branches. Relative dry mass allocation to branches, twigs and leaves, length of twigs per cm of branches and specific leaf area were not affected by pruning and water supply. Trees with shorter branches had a higher leaf area density. As opposed to an allometric relationship between the average diameter of primary branches and total above ground biomass, our data suggest that these traits were not constantly correlated. Our data indicate that the length of newly formed twigs, where the leaves are attached to, can be related to the total length of already established branches. Leaf area density and relative dry mass allocation to leaves were not affected by the two pruning techniques, indicating that pruning differences in leaf area size were proportionally converted to corresponding pruning differences in the canopy volume exploited by plants. The results reported in this study are relevant for understanding jatropha growth. It helps farmers first for a better plantation management and researchers as well as contribution to future modelling purpose concerning jatropha growth under variable climatic conditions. Additionally, it should complement information for a better set of priorities in research, contribute indirectly to breeding programs and adjust agricultural policies in terms of encountering global change.