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Jatropha Curcas L.: A Potential Bioenergy Crop - On field research in Belize


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Jatropha Curcas L.: A Potential Bioenergy Crop - On field research in Belize

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Jatropha Curcas L.: A Potential Bioenergy Crop - On field research in Belize

  1. 1. Università degli Studi di Padova Facoltà di Agraria Dipartimento di Biotecnologie Agrarie Laurea Magistrale in Scienze e Tecnologie Agrarie Jatropha curcas L., a potential bioenergy crop. On field research in Belize.Relatore:Prof. Mario Malagoli, Università degli Studi di PadovaCorrelatore:Dr. ir. Raymond Jongschaap, Wageningen University and Research centre,Plant Research International Laureando: Berardo da Schio Matricola n° 588712 Anno Accademico 2009/2010
  2. 2. If you use information from this M.Sc. dissertation document, please citeand refer to:da Schio, B., 2010. Jatropha curcas L., a potential bioenergy crop. On field research in Belize. M.Sc. dissertation. Padua University, Italy and Wageningen University and Research centre, Plant Research International, the Netherlands.
  3. 3. “Sub umbra floreo”. National motto of Belize.
  4. 4. Table of ContentsList of Abbreviations.........................................................................................................7Abstract............................................................................................................................111.Introduction..................................................................................................................13 1.1 Energy crisis and global climate...........................................................................13 1.2 Jatropha curcas L., a potential bioenergy crop....................................................18 1.2.1 Knowledge gaps in Jatropha curcas L. research..........................................28 1.2.2 Selection of knowledge gaps and justification..............................................31 1.3 Aim and objectives of the thesis...........................................................................332.Materials and Methods.................................................................................................35 2.1 Research at PRI Wageningen, the Netherlands.....................................................35 2.2 On field research in Belize, Central America.......................................................36 2.2.1 Climate data..................................................................................................39 2.2.2 Maya Ranch trial...........................................................................................40 2.2.3 Warrie Head trial...........................................................................................44 2.2.4 Central Farm trial..........................................................................................45 2.3 Statistical analysis.................................................................................................493.Results and discussions................................................................................................51 3.1 Important drivers for Jatropha curcas L. growth and development and how are these for Belize...........................................................................................................51 3.1.1 Radiation and light interception....................................................................51 3.1.2 Temperature...................................................................................................52 3.1.3 Water.............................................................................................................53 3.1.4 Vapour pressure and wind speed...................................................................53 3.2 Response of genetically different accessions to available resources in Belize.....55 3.2.1 Seed dimension and weight...........................................................................55 3.2.2 Seed germination rate....................................................................................58 3.2.3 Biomass development at nursery stage: LA, fresh weight, taproot length....60
  5. 5. Table of Contents 3.3 Resources use efficiency and optimization for jatropha crop conditions in Belize.. .....................................................................................................................................63 3.3.1 Plant density..................................................................................................63 3.3.2 Plant spacing.................................................................................................64 3.3.3 Crop management.........................................................................................71 3.4 Discussions...........................................................................................................804.Conclusions..................................................................................................................855.Acknowledgements......................................................................................................89Annex 1. Growth parameters and sustainability indicators tables...................................91Annex 2. Experimental designs.......................................................................................99References.....................................................................................................................107 6
  6. 6. List of AbbreviationsAET............... Actual Evapo-Transpirationaft. ….............after (in Annex 1)agr. …............ agricultural (in Annex 1)BNMS............Belize National Meteorological ServiceBT.................. Bullet TreeCBD...............Convention on Biological DiversityCDM.............. Clean Development MechanismCF.................. Central FarmCOCyTECH.. Consejo de Ciencia y Tecnologíacomm. …....... communicationDM................ Dry matterDMA............. Dry matter assignmentEEP................ Energy and Environment PartnershipEM................. Effective Micro-organismsERA-ARD..... Agricultural Research for Development; Dimension of the European Research AreaEU..................European UnionFACT............. Fuel on Agricultural Common TechnologyFAO............... Food and Agriculture Organization of the United NationsGHG.............. Greenhouse gasesGUARD.........Galen University – Applied Research and Development for Sustainability InstituteHI...................Harvest indexIEA................ International Energy AgencyIPCC.............. International Panel on Climate ChangeJC...................Jatropha curcas L. (in Annex 1)LA..................Leaf AreaLAI................ Leaf Area IndexLCA............... Life Cycle AnalysisMR.................Maya RanchNBS............... Nucleotide Binding SiteNGO.............. Non Governmental Organization
  7. 7. List of AbbreviationsOAS............... Organization of the American StatesOM.................Organic MatterPET................ Potential Evapo-Transpirationpm.................. parameter (in Annex 1)PRI.................Plant Research InternationalPS...................Production system (in Annex 1)T,M,B.............Top, Middle, Bottom branches (in Annex 1)TSDF..............Tropical Studies and Development FoundationUB................. University of BelizeUNEP............. United Nations Environment ProgrammeUNDP.............United Nations Development ProgrammeUNFCCC....... United Nations Framework Convention on Climate ChangeUSD............... United States DollarWH................ Warrie HeadWUR..............Wageningen University and Research centre 8
  8. 8. Ai miei genitori,e ai miei nonni.
  9. 9. AbstractPotentials of bioenergy crop Jatropha curcas L. are investigated through field trials inCayo District, Belize, Central America. Crop growth and development are monitored intwo jatropha plantations of one and six years, respectively in Warrie Head and MayaRanch. A third plantation is set up in Central Farm, in the framework of the 1stCoordinated Call for a Transnational Research Activity under the ERA-ARD Net:Bioenergy – an opportunity or threat for the rural poor, in the project Bioenergy inAfrica and Central America – Opportunities and Risks of Jatropha and Related Crops.Biomass development is assessed through measurements of dry fruit yield, LAIdevelopment, length of effective branch, seed dimensions and weight, fruit to seed ratioand seed to kernel ratio and seed germination test in relation to different crop variables,according to the different trials: management, such as pruning and cropping system(monoculture, intercropping and living fence), genotype, plant spacing and plantdensity. Outputs on biomass development are linked with weather variables data, kindlyprovided by the National Meteorological and Hydrological service of Belize.Results indicate that Jatropha curcas L. has promising potentials to play a decisive rolein bioenergy scenario in Belize and the Region, for the favourable pedoclimaticsituation and the availability of genetic resources.Key words: Jatropha curcas L. – Biofuels – LAI development – Belize – Tropicalagriculture. RiassuntoIl potenziale della coltura energetica Jatropha curcas L. viene investigato in prove dicampo nel Distretto di Cayo, Belize, America Centrale. La crescita e lo sviluppo dellacoltura vengono monitorati in due piantagioni di uno e sei anni, rispettivamente aWarrie Head e a Maya Ranch. Una terza piantagione viene messa a dimora a CentralFarm, nel contesto della 1st Coordinated Call for a Transnational Research Activityunder the ERA-ARD Net: Bioenergy – an opportunity or threat for the rural poor, nelprogetto Bioenergy in Africa and Central America – Opportunities and Risks of
  10. 10. AbstractJatropha and Related Crops.Lo sviluppo della biomassa è stimato attraverso misurazioni di: produzione di frutta,sviluppo del LAI, lunghezza effettiva dei rami, dimensioni e peso dei semi, rapporto inpeso di frutto e seme, prove di germinazione, in relazione a variabili differenti, secondole diverse prove: gestione colturale, come potatura e sistema colturale (monocoltura,consociazione e recinto verde) genotipo, spaziatura e densità. Lo sviluppo dellabiomassa viene confrontato in relazione ai dati sulle variabili climatiche, gentilmentemessi a disposizione del servizio Meteorologico ed Idrologico Nazionale del Belize.I risultati indicano che Jatropha curcas L. mostra promettenti potenziali nello scenariobioenergetico del Belize e della Regione, in ragione della situazione pedoclimaticafavorevole e della disponibilità di risorse genetiche.Parole chiave: Jatropha curcas L. – Biocombustibili – indice di area fogliare LAI –Belize – Agricoltura tropicale. 12
  11. 11. 1. IntroductionEnergy availability and energy use are issues of global concern and have been underresearch worldwide for a long time. Attention is mostly given to reduce energyconsumption and to detect new and renewable energy resources, in order to cope withthe world energy crisis. Two main processes are responsible for this situation: first, theincreasing population and development rates are rapidly multiplying the global energydemand in many countries; secondly, the great share that traditional fossil fuels occupyon the global energy consumption can hardly be sustained. In fact, the ongoing fossilfuels depletion has reached a stage where the current reserves seem not enough forfuture needs. Furthermore the role of fossil fuels on climate change and global warmingcan no longer be neglected (IPCC, 2007).1.1 Energy crisis and global climateHigh fossil fuel prices, the risks of fossil fuel dependence and the increasing greenhousegas (GHG) emissions derived from this kind of fuels are the main reasons to find newand renewable energy sources for the coming years (FAO, 2008). In fact the currentenergy crisis is mainly due to the high dependence on fossil fuels. It is now evident thatoil consumption is drastically increasing, while the reserves are rapidly diminishing(Dowlatabadi, 2006), so it would be more relevant to talk about oil crisis than energycrisis. Current global trends in energy supply and consumption are patentlyunsustainable: environmentally, economically and socially. That indicates a global needto secure the supply of reliable and affordable energy and to effect a rapidtransformation to a low-carbon efficient and environmentally benign system of energysupply. It is also clear that current energy fossil fuel consumption trend will have severeconsequences on natural ecosystems and social communities. Switching to renewableenergy will therefore reduce global warming and curb actual trends (IEA, 2006). Theseare the reasons why a search for alternatives to fossil fuels, such as renewable energyfrom solar, wind, water, biomass and nuclear, has been provoked.All renewable energy options have pros and cons and a global analysis should beundertaken for each one of them. Various aspects of renewable energies will be
  12. 12. 1.Introductiondiscussed, but nuclear energy will not be taken into consideration.The matter of renewable energy involves different forms and sources of energy.According to the Unified Bio-Energy Terminology definition (FAO, 2004), renewableenergy consists of energy produced and/or derived from sources infinitely renovated(hydro, solar, wind) or generated by renewable combustibles (sustainably producedbiomass). Renewable energy offers an interesting option to reduce fossil fuelsdependence and to reach climate change mitigation and if well consciously andsustainably managed, it may help to preserve biodiversity, water and soil reserves, aswell as human livelihoods.Due to its importance, international actors have expressed themselves on the subject.The United Nations Framework Convention on Climate Change (UNFCCC, 1992)supports bioenergy as one of the “precautionary measures to anticipate, prevent orminimize the causes of climate change”. The 1997 Kyoto Protocol to the UNFCCCrecognizes the importance of renewable energy as a contributor to mitigating climatechange, with a view to assisting developing countries in achieving sustainabledevelopment and enabling industrialized countries to comply with their quantitativeemission targets thanks to the Clean Development Mechanism. The Convention onBiological Diversity (UNEP, 1992) is relevant to sustainable bioenergy development asit commits parties to biodiversity conservation, the sustainable use of its componentsand the fair and equitable sharing of benefits arising from the use of genetic resources.Many different solutions to face worldwide changes on climate and on energy demandare available. Alternatives to fossil fuels seem in fact numerous. The appropriatesolution to alleviate fossil fuel crisis and related climatic problems may vary accordingto the local situation and taking into account social, economic and environmentalspheres. An interesting option that should be seriously taken into account in relation tothe local factors is represented by biofuels produced directly or indirectly from biomass.They have been subject of many claims and researches during the past decades, andthey are now classified by the FAO as “First-generation” and “Second-generation”biofuels. First generation biofuels are the ones mainly derived from food-crops, 14
  13. 13. 1.Introductionincluding sugar- and starch-based bioethanol and oilseed based biodiesel; while Secondgeneration biofuels are the ones derived from non-food crop agricultural and forestryproducts, making use of the lignin, cellulose and hemicellulose components of plants(FAO, 2008). Both first and second generation biofuels present good opportunities butalso have negative sides. In fact, on the one hand they are a remarkable option tocombat climate change and to reduce fossil fuel dependency, while on the other handthey can directly or indirectly affect food security and do not play a relevant role inGHG emissions mitigation. It is important to bear in mind that biofuels often competefor land, water and nutrient resources and they can provoke an increase of food price.However, in an optimized setting, (local) energy supply may contribute to productivityincrease and to the prosperity of livelihoods. A way to check the effectiveness of climatechange mitigation through biofuel production and use should be found, which meansidentifying tools that allow comparing energy and GHG emission balances (inputs andoutputs) and indicating if a better action is effectively accomplished. Ultimately, theimpact of biofuels on livelihood should not be disregarded.To date, energy and GHG emission balances are of high concern as researches on thisissue provoke great discussions. To loose this worry, life cycle assessments (LCA) areused as tools that take into account different parameters and variables to define the bestimprovement on an environmental scale: impacts are evaluated after different decisionsand management actions over the whole life cycle of a specific product. Indeed, thebenefits coming from renewable energies strategy and management implementation arelinked to many variables, as the good opportunity of favourably impacting theenvironment and the farmers livelihoods. With regard to all these concerns, a furtherbroad question is attracting people’s attention and animating the worldwide debate onenergy: the struggle between local and global energy. In fact, energy consumption is anissue present everywhere the humanity stands, and people are arguing on who is theactor, on how and why the energy (or oil) production and distribution are controlled.Globally, there is an increasing energy demand and a global concern on occurringclimate change, as well as a worldwide spread awareness of the necessity of finding 15
  14. 14. 1.Introductionalternatives. With regard to that, an emergent question is showing up: what consequencewould bring the development of a global energy based community and what if it is localenergy based. According to the previous discussion, it is important to remember thatglobal energy production can involve high energy losses due to the transportation itselfand risks of energy market monopoly or oligopoly. Local energy options seem to besocially sustainable and economically viable, if proper infrastructures and services areprovided. Local energy development starts at a local scale, identifying the potentialalternatives to put into effect: in this regard, biofuels from agricultural crops oftenrepresent a valuable opportunity. In relation to the local environmental and socialsituations and to the pedoclimatic characteristics, many could be the suitable crops:sugar crops (sugar cane, sugar beet, sweet sorghum), starchy crops (maize, wheat,barley, rye, potatoes, cassava) and cellulosic material (switchgrass, Mischantus, willow,poplar, crop stover) for the production of ethanol; oil crops (rapeseed, oil palm,soybean, sunflower, peanut, Jatropha) for the production of biodiesel; biomass comingfrom different crops but also from agro-industrial by-products and municipal wastes forthe production of biogas (FAO, 2008).However, despite some possible negative impacts, many are the potential benefits ofbioenergy development. Indeed, it is clear the strong call for implementation strategiesthat will act on the development of this sector. Often, well balanced policies andaccurate actions can strongly operate to maximize positive effects and reduce thenegative ones. As positive effects there are: diversification of agricultural output,stimulation of rural development and contribution to poverty reduction, increase in foodprices and higher income for farmers, development of infrastructure and employment inrural areas, lower greenhouse gas emissions, increased investment in land rehabilitation,new revenues generated from the use of wood and agricultural residues, and fromcarbon credits, reduction in energy dependence and diversification of domestic energysupply, especially in rural areas, access to affordable and clean energy for small andmedium-sized rural enterprises. On the other hand, potential negative effects areaddressed to as reduced local food availability if energy crop plantations replace 16
  15. 15. 1.Introductionsubsistence farmland and increased food prices for consumers. Demand for land forenergy crops may increase deforestation, reduce biodiversity and increase GHGemissions. Increased number of pollutants, modification to requirements for vehiclesand fuel infrastructure, higher fuel production costs, increased wood removals leadingto degradation of forest ecosystems, displacement of small farmers and concentration ofland tenure and incomes, reduced soil quality and fertility from intensive cultivation ofbioenergy crops, distortion of subsidies on other sectors and creation of inequitiesacross countries represent some other alarming impacts (FAO, 2008).A strong focus on this issue is necessary and more importance should be given to theproblems of biofuels’ production, by looking at them from an agricultural point of view.To what concerns the fuels coming from food crops, the main problems seem to be thecompetition for their destination as human food or animal feedstock and from thecompetition for agricultural land resources, water, energy and nutrients. The fearcoming from the cultivation of food crops for energy production is also due to themismanagement of these crops. In fact, while climate change mitigation can be partlyachieved (if it is truly proved for some produce, for others should be cautiouslyexplored), mismanagement can lead to a loss of biodiversity, especially in the case ofrepeated monoculture over the years, and in a reduced efficiency of water and soilresources that are of vital importance. That is especially the case at the moment in non-industrialized countries, where the demand for large area to place bioenergy plantationsis increasing (Wood, 2005; von Braun and Meinzen-Dick, 2009; Daey Ouwens et al.,2007). The other option, represented by the use of “second-generation” biofuels, seemsto be of difficult and slow spreading in most countries at the present day, due to the lackin technology knowledge and resources for processing the lignin component that is stillunder development (FAO, 2008). What should not be forgotten is that second generationbiofuels might not affect the availability of food but they do compete for land, water,nutrients and energy.Thence, biofuels represent a valuable solution to mitigate global warming and to reduceoil dependence. Nevertheless, significant objections are still heard against their use, as 17
  16. 16. 1.Introductiontheir consequences on communities could be positive as well as negative. Majorconcerns lie in the selection of the fuel crop and its management in the cultivation andprocessing steps: solutions may vary according to the regional context. Moreover, theuse of some fuel crops is controversial, as they have been proven to be not enoughefficient or useful. For some others, more research is required and their use as an energyfeedstock will heavily depend on how this research is carried out and how the results arepresented. Among these last mentioned, a relatively new energy crop is Jatropha curcasL. (Figures 1.1 and 1.2).Figure 1.1. Jatropha curcas L. plantation at Figure 1.2. Jatropha curcas L. fruits, in Mayafruiting stage, in Maya Ranch, Belize, July Ranch, Belize, July 22nd, 2009.22nd, 2009.1.2 Jatropha curcas L., a potential bioenergy cropJatropha curcas L. is a deciduous monoecious perennial shrub or small tree belongingto the botanical family of Euphorbiaceae, to the tribe Jatropheae of the subfamilyCrotonoideae. Common name varies according to the region: in English it is calledphysic nut, while in Italian it is known as ricino dinferno. J. curcas probablyoriginated in southern Mexico or neighbouring parts of Central America, which are theonly areas where it has often been collected from undisturbed vegetations. It was thendistributed all over the world by Portuguese seafarers in the XVII century and is now 18
  17. 17. 1.Introductionnaturalized throughout the tropics and subtropics (Figure 1.3). Different parts of J.curcas are used for a range of medicinal purposes; moreover it is a source of oil used forsoap production and as a source of energy, as mentioned before; it is also an importanthedge plant (Baldrati, 1950; Henning, 2007). Hereunder, a review of jatropha plants,fruits, seeds and leaves (Figures 1.4, 1.5, 1.6 and 1.7). Figure 1.3. Global indication of the most suitable climate conditions for the growth of Jatropha (J. curcas L.) (30°N, 35°S) and Oil palm (Elaeis guineensis Jacq.) (4°N, 8°S). Source: Claims and Facts on Jatropha curcas L., Jongschaap et al., 2007.Figure 1.4. Row of six years old Jatropha Figure 1.5. Jatropha curcas L. dry fruit coatscurcas L. plants pruned at four years, in and seeds. In the background, ArachisMaya Ranch, Belize, July 22nd, 2009. pintoii growing as intercrop with jatropha, in Maya Ranch, Belize, July 22nd, 2009. 19
  18. 18. 1.IntroductionFigure 1.6. One year old Jatropha curcas L. Figure 1.7. Six years old fruiting Jatrophaplant, in Warrie Head, Belize, July 22nd, curcas L. plants, in Maya Ranch, Belize, July2009. 22nd, 2009.The plant ecophysiology and the botanical features have been investigated. The plantdevelops a deep taproot and initially four shallow lateral roots (Figure 1.8). The stem,arising from a thick, perennial rootstock, with watery to whitish latex, has a barksmooth, grey or reddish, shiny, peeling off in papery scales. Leaves are alternate,simple, petioled and glabrous, with a blade broadly ovate in outline, usually shallowly5-lobed and margins usually entire. Terminal inflorescences contain unisexual flowers.The fruit is a broadly ellipsoid capsule, smooth-skinned containing three ellipsoid seeds,1-2 cm long, mottled black and coarsely pitted. Growth in J. curcas is intermittent andsympodial, dormancy is induced by fluctuations in rainfall, temperature and light butnot all plants respond simultaneously. Pollination seems to be carried out by honeybeesand beetles (Bhattacharaya et al., 2005) and moths (Henning, 2007). In flowering, thefemale flowers open one or two days before the males one; male flowers last only oneday. Seed never sets in indoor cultivation unless the flowers are pollinated by hand. J.curcas occurs in semi-arid tropical and warm subtropical climates with meanpedoclimatic surviving requirements as the followings: daily temperatures of 20-30°C,annual rainfall of 300-600mm (but resistant to periods of drought of up to sevenmonths), absence of frost (Figure 1.9). 20
  19. 19. 1.IntroductionFigure 1.8. Particular of Jatropha curcas L. Figure 1.9. Six years old Jatropha curcas L.root system. Central taproot and four lateral plantation after an extraordinary dry month,roots are evident, in Belmopan, Belize, in Maya Ranch, October 28th, 2009.November 27th, 2009.The main inputs for the production of oil-bearing fruits of J. curcas are land areaincluding the prevalent site characteristics, plantation establishment practices andplantation management practices. The outputs are the seeds and other biomass elements(Achten et al., 2008). J. curcas can grow in a wide range of soils: on degraded, sandy orgravelly and even saline soil with low nutrient content. Nevertheless, clay soils areunsuitable for the plant if water logging or saturation occurs due to the climaticconditions. It is clear that J. curcas responds highly when growing on well aerated soils.Sandy to loamy soils seem to be a best fit. Optimal pH reaction is considered between 6and 8.5. The plant is well adapted to marginal soils with low nutrient content but inorder to support a high biomass production the crop shows a high demand for nitrogenand phosphorus fertilization (Henning, 2007; Daey Ouwens et al., 2007). Among soilproprieties, pH, EC, CaCO3, organic C and clay significantly affect the availability ofnutrients, thus soil conditions reflect the effect of jatropha cultivation practices on adegraded soil. From the perspective of both soil structure and carbon and nitrogensequestration, jatropha cultivation under minimal soil disturbance can serve‘environmental functions’. In fact, jatropha cultivation improves soil resistance to winderosion and enhanced macro-aggregate stability to water erosion. Under jatropha,increased potential carbon sequestration rates are possible as stable micro-aggregates 21
  20. 20. 1.Introductioncan offer protection to organic carbon. Therefore jatropha cultivation programmes willnot only serve as a source of income-generation to resource-poor farmers but will alsoimprove the quality of their soils in the long run (Ogunwole et al., 2008).Propagation is done by seeds or cuttings. Plants raised from seed are more resistant todrought than those raised from cuttings, because of the taproot they develop. Thedevelopment of root system is then different, according to the originating part of theplant (Achten et al., 2007). The taproot enables a straighter and deeper root systemgrowth so to extract moisture from deeper layers of the soil. This root structure is alsopreferable in intercropping systems to minimize the competition for water and nutrientsbetween the different crops. Thereafter, nursery-grown seedlings have a higher survivalrate than direct-seeded ones and produce seeds earlier (Figure 1.10). Seeds in nursery ordirect seeding with seed treatment is recommended (Daey Ouwens et al., 2007). Seedsoaking in cold water for 24 hours is suggested for better and quick germination(Kaushik et al., 2007), although it might influence more the germination celerity than itsrate (Sengfelder, personal comm.). At the onset of the rains the seedlings can be plantedin the field (Heller, 1996). It was noted that spacing of plants is a trade off betweenbiomass and fruit production. Thus, optimum spacing is differently achieved dependingon weather situation, site characteristic and intended objective (Achten et al., 2008).Irrigation will depend on the climatic conditions of the location. Although J. curcascan survive precipitation as low as 300mm by shedding its leaves, it does not producewell under such conditions. Minimum and optimal rainfalls to produce fruits areassessed on values of 600mm ha-1 y-1 and 1000-1500mm ha-1 y-1. Water and rains afterperiods of drought will induce blossoming. Hence, too much rain and humidity willprovoke fungus, thus high rainfall might require other spacing (Daey Ouwens et al.,2007). Indeed, an economic sustainable oil production is achieved with higher minimumrequirements of water of at least 750 mm annual rainfall or supplementary irrigation(Henning, 2007). Plantations aiming at oil production might also need artificial ororganic fertilization. Fertilizers at least compensate the nutrient removal due to harvestor management practice (e.g. pruning). Simultaneous reclamation of barren lands and 22
  21. 21. 1.Introductionbiodiesel production will inevitably imply use of fertilizer and irrigation (Achten et al.,2008).Pruning is a very important issue as it determines to a large extent, although notcompletely, seed yield in each site and it can facilitate manual and mechanicalharvesting of fruits (Figure 1.11). Canopy size determines the maximum number offlowering branches. Large trees on a low planting density or smaller plants on highdensities can apparently both result in sufficient flowering branches (Daey Ouwens,2007). The pruning should be done when the tree sheds leaves and enters a period ofdormancy (Kaushik et al., 2007), that is usually coinciding with the dry season. Culturalpractices in new plantations, thence, include regular weeding, pruning and fertilization.Standard management count on a plant density field design of 1350-2500 plants ha -1(Henning, 2007).Figure 1.10. Jatropha curcas L. seedlings aweek after sowing, in Bullet Tree, Belize, Figure 1.11. Six years old Jatropha curcas L.September 30th, 2009. plant pruned two years before, in Maya Ranch, Belize, July 22nd, 2009.Diseases and pests attacks should not be underestimated. Opinions on this issue arecontrasting. In fact, Henning (2007) says that intervention against pests and diseasesoccurs rarely and just in the case of powdery mildew (Uncinula necator), Alternariaspp., and caterpillars of Spodoptera litura and several species of phytophagous beetles,and particular attention must be put on intercrops grown together with J. curcas, as it 23
  22. 22. 1.Introductioncan be an alternative host (e.g. Cassava mosaic virus). While Daey Ouwens et al. (2007)say that the plant is vulnerable to most common pests and diseases found in food crops,adding that most of these pests and diseases can be treated fairly easily and, if required,biologically.Basic agricultural operations are done manually, and so harvesting and separation ofseeds from fruits. Handling after harvesting foresees a careful exsiccation in the shadeuntil 6-9% moisture content. Subsequently the extraction of the oil can be donefollowing different techniques (Henning, 2007). The reported yields range fromextremely low to high; Jongschaap et al. (2007) conclude to a potential yield range of1.5-7.8 dry seed ha-1 y-1. As mentioned above, yield depends on site characteristics(temperature, radiation, rainfall, soil type and soil fertility), genetics (a strict selection ofseeds or cuttings leads to more uniformity in offspring and higher yields per plant),plant age and management (propagation method, spacing, pruning, fertilizing, irrigation,etc.) (Daey Ouwens et al., 2007; Achten et al., 2008).The oil contained in the seeds, around 35% by weight (Baldrati, 1950; Kandpal andMadan, 1995; Ginwal et al., 2004; Jongschaap et al., 2007), has to be expelled orextracted. For extraction of the jatropha oil two main methods have been identified:mechanical extraction (with manual ram press or engine driven screw press) andchemical extraction (aqueous enzymatic or solvent oil extraction). Finally the oil maybe refined in a continuous transesterification reactor to produce biofuel or diesel oil andglycerol as a valuable by-product. The oil quality is dependent on the interaction ofenvironment and genetics (Jongschaap and van Loo, 2009; Achten et al., 2008). Thus,the cake attributes change in relation to the oil characteristics and the oil extractionmethod used. Anyway, the cake contains high-quality proteins and various toxins. Thepresence of biodegradable toxins makes the fertilizing cake simultaneously serving asbiopesticide/insecticide and molluscicide. Anyway, it is advisable to check the absenceof phorbol esters in the crops grown on jatropha cake fertilized land, certainly in cropsfor human consumption. Digesting the cake and bringing the effluent back to the field isthought to be the best practice at present from an environmental point of view. Due to 24
  23. 23. 1.Introductionthe toxicity of the seeds and oils, some attention should be paid to the human health andwork environment impact categories (Achten et al., 2008).Available genetic resources show several types of J. curcas. Low-toxic type fromMexico, type with larger leaves and larger but fewer fruits and seeds from Nicaragua,male sterile type which produce more fruits than normal types, just to quote someexamples. A study on 200 J. curcas accessions from different regions around the worldhighlighted, among other characteristics, the differences in oil composition that could beregionally identified (Jongschaap and van Loo, 2009). In order to start breeding thegenetic variation needs to be assessed. Most plant material used so far is derived fromsimple selection within semi-wild populations or landraces. Between-plant variation ofvigour and seed yield are tremendous and great genetic improvement in seed yields andother important characteristics may, therefore, be expected from systematic breeding(Figure 1.12). Obviously, oil yield per hectare will dominate breeding objectives for J.curcas cultivars for biofuel production. Cultivars with compact growth would facilitateharvesting (Henning, 2007). Literature reports lack of genetic variation. To date, it isassessed a high phenotypic variation (e.g. plant architecture) in material from LatinAmerica (Figure 1.13). Genetic variability was found low in African and Indian J.curcas accessions but high in Guatemalan and other Latin American ones. Diversity inJ. curcas should be found in wild species, in their centre of origin in Mexico, Centraland South America (Jongschaap and van Loo, 2009; Montes et al., 2008). Plantbreeding programmes should be carried out after a more through analysis of the existinggenetic resources and variability, that would allow getting the characteristics that wouldbe required. Among the most important and urgent features to be investigated, there are:toxicity of seeds, oil-seed and seedcake (source of protein that could be suitable foranimal feedstock); drought resistance and water requirements under differentpedoclimatic situations; plant susceptibility to pests and diseases. 25
  24. 24. 1.IntroductionFigure 1.12. Seed coats and kernels of three Figure 1.13. Particular of stem and lateralaccessions of Jatropha curcas L., in branches of a year old Jatropha curcas L.Belmopan, Belize, November 2nd, 2009. plant, in Warrie Head, July 22nd, 2009.Concerning environmental impacts of J. curcas production system, the main issues arethe energy balance, impact on global warming potential and land use impact. Energybalance of J. curcas biodiesel is reported to be positive and the total energy inputs intothe crop to the energy output ratio is estimated at 1:4-5 (Henning, 2007). The availableinformation shows that energy balance improvement options lay in the cultivation,where irrigation and fertilization are the most energy intensive practices, andtransesterification steps. How positive the balance is in reality, will mainly depend onhow efficiently the by-products of the system are used. Impact on global warmingpotential showed a reduction of GHG emissions for the production of biodiesel from J.curcas in comparison to fossil fuels. However, the removal of (semi-) natural forest forthe introduction of J. curcas is expected to have a significant negative effect on theGHG balance of the whole life cycle. Ultimately, it is expected that land occupationimpact of J. curcas on the soil will be positive, as the plant is observed to improve soilstructure, is strongly believed to control and prevent soil erosion and sequestratescarbon. Nonetheless, being an exotic species in most actual growing areas, the impact ofland use change towards J. curcas on biodiversity is expected to be negative, althoughthis will largely depend on the mix of land use which is replaced by J. curcas and onhow the plant is cultivated (Achten et al., 2008).J. curcas’ considerable potential as an oil crop for biofuel purposes at relatively low 26
  25. 25. 1.Introductioncosts and modest demands on the local agro-ecosystem has received much attention inrecent years. It is foreseen that within the next decade or so, J. curcas will become amajor source of renewable energy in the drier rural areas of (sub) tropical Asia, Africaand America (Henning, 2007). The promise of J. curcas as a species to produce highquantity and quality feedstock for bioenergy is considerable. First, yields are expectedto increase over the years as seed improvement takes effect; they are expected to reach 6to 7 ton dry seeds ha-1 y-1 within few years, but only under optimal climate conditions,using high yielding strains, and optimal soil fertility conditions. Looking at suchpromise, it is concluded that jatropha might be an alternative for other oil producingplants such as oil palm, especially for less humid areas (Daey Ouwens, 2007).The role of J. curcas in bioenergy generation looks like to be of great interest; in fact,biodiesel production from jatropha seeds give an optimistic impression of the capabilityto combine the low-technology inputs required for oil production with other agriculturalinteresting claims on the plant. In fact, many are the claims regarding J. curcas, and itsdevelopment as an agricultural crop appears to have many positive effects. The present-day hype for this plant comes from the theoretical combination of all the good featuresthat characterize J. curcas cultivation, however they are not always scientifically provenand barely come out altogether simultaneously in the same site. In fact, many goodcharacteristics of this plant appear to exist because of its rusticity and an intensiveexploitation it is not like to be supported by scientifically sound agronomic data. Indeed,often good resistance characteristics are not linked with high productivity values(Jongschaap et al., 2007). To understand better the limits and the potentials that J.curcas crop growth may result from a more intensive and focused farming, the mainagronomic characteristics, the physiological behaviours, the reactions to different sitesand the relevance of genotype or environmental influences should be known, and if not,they should be meticulously detected and, afterwards, explained to farmers. Keepingthis assessment in mind and looking at an objective of J. curcas cultivation techniquesimprovement, knowledge gaps on botanical features, potential utilizations, claims andfacts regarding J. curcas and its production system will be hereunder briefly described 27
  26. 26. 1.Introductionand explained. In any case, a clear statement can be extrapolated: the plant cannotperform all its functions together at the best level.1.2.1 Knowledge gaps in Jatropha curcas L. researchDespite the huge interest that J. curcas production system has attracted by now, a lackof knowledge and available data is evident. The main gaps concern some basicagronomic characteristics, the application of the good agricultural practices, thedevelopment of a complete J. curcas production system (including oil yieldcharacteristics and oil processing) and the input/output balances at all these stages.Moreover, information is still required to assess the nutrient requirements and the drymatter assignment in different agricultural settings and pedoclimatic conditions. There islack of data also in reported genetic variability that would allow beginning plantbreeding programmes. Further research towards the discovery of the potential ofutilization of other J. curcas products and by-products would be very welcome.Accurate data on yield and on its characteristics are missing. In order to respond to theJ. curcas oil production want of a list of countries, in which incredible large areas, thatare drastically increasing, are planned to be grown with this plant, reliable informationon crop requirements and climate/soil characteristics are still very much required (DaeyOuwens et al., 2007). Much agronomic and breeding work needs still to be done tomaximize oil production potential per ha and thus improve the economic sustainabilityof jatropha oil production. To this, rapid multiplication techniques and facilities have tobe developed to make improved planting material available in adequate amounts. This isespecially urgent as planting of unimproved material not only leads to low returns oninvestments but may also lead to a loss of interest in this crop (Henning, 2007).Concerning the plant cultivation, substantial efforts should be made to streamlineobservations in current jatropha planting sites, to implement specific experiments forunravelling the impact of different production factors on crop performance and toexchange knowledge and information, in order to prevent unjustified investments. It isrecognized that the main knowledge gaps are situated in the cultivation step, where a 28
  27. 27. 1.Introductiondescription of the best practice and the potential environmental risks or benefits areneeded. In fact, basic agronomic proprieties are not exhaustively understood and theenvironmental effects have not been investigated yet (Achten et al., 2008). Correctspacing should be identified depending on different intended objectives and much hasstill to be learned from plant manipulation, from more or less intensive pruning orcurving of branches, at different moments. As a new technology, the micropropagationis being developed by Manurung (Daey Ouwens et al., 2007; Achten et al., 2008).Taproot potential has not been investigated scientifically. The susceptibility of J. curcasto pests and diseases is a source of discussion and is believed to depend on themanagement intensity. More experiments are needed where the growth effect ondifferent kinds of crops are monitored in intercropping systems. Impacts on soilstructure, water-holding capacity, soil decomposition, organic matter content and soilbiological activity should be brought under detailed investigation as well. Dominantrole of environment over genetics in seed size, seed weight and oil content (Achten etal., 2008) should be more deeply investigated. Much research is still necessary toimprove yield, to exactly understand the energy efficiency of the plant under differentconditions, to allow use of bioproducts such as oil cake as animal fodder (Daey Ouwenset al., 2007).Nutrient requirements for maximum oil production are not well-defined for J. curcas(Henning, 2007). No information is available on nutrient cycles and the impact on soilbiological life (Achten et al., 2008). The relation between plant nutrients, organic mattercontent of the soil and micronutrients and yields is not fully understood (Daey Ouwenset al., 2007). Jatropha has not been domesticated yet and basic knowledge of its soil-plant relations is required for the development of appropriate agricultural techniques.Very little is known about foliar nutrient content of jatropha and soil-plant relationship,which is essential to domesticate the plant and establish the nutrients requirements(Chaudhary et al., 2008).The input levels to optimize the harvest index (HI) in given conditions are yet to bequantified. Very limited information is available regarding acidification, eutrophication, 29
  28. 28. 1.Introductionand other LCA impact categories of the J. curcas production cycle. Increasedinvestigation of the cultivation step in the production of jatropha biodiesel will enableresearchers to assess the specific contribution of the plant in these impact categories aswell. As the reduction of global warming potential is one of the main aims of the J.curcas biodiesel system, this confirms the research need on input-responsiveness of theJ. curcas cultivation step.Good documented yield data are still scarce. Seed yield and biomass production indifferent environmental and abiotic settings, varying provenances or accessions andapplying different levels of different inputs should be monitored in order to discover theinput-responsiveness of the plant in different settings as well as the interactions betweenthe different inputs and the interaction between the environmental and genetic set-upsand the inputs. Notwithstanding, there is still insufficient information to account thenutrient and water needs for specific environmental and genetic set-ups. The actualpotential of J. curcas cultivation should be explored, as it is not clear if the plant is ableto produce ecologically and socio-economically viable amounts of energy in barrensituation (Achten et al., 2008). From selection of basic plant material up to yield, thereare many options, with a lot of variation in available data and not enough informationfor optimization. More research should also be initiated on medicinal proprieties ofdifferent parts of the plant, e.g. wound healing, antimalarial and anti-HIV effects, andinvestigation of the agronomic and medicinal potential of other Jatropha species wouldbe valuable as well (Henning, 2007).J. curcas is still a wild plant with a wide variation in growth, production and qualitycharacteristics. In order to start breeding towards high yielding biodiesel plantations, thebest suitable germplasm has to be identified for different cultivation situations(Henning, 2007; Daey Ouwens et al., 2007; Achten et al., 2008). For this reason,research makes progresses thank to new patent free molecular marker technology :conserved sequence based on NBS-gene family. A starting point in this sense couldreasonably be intercrossing ‘elite’ J. curcas accessions (e.g. ‘Cabo verde’) with lowtoxic and toxic accessions as starting point for breeding, now that genetic analysis of 30
  29. 29. 1.Introductionsegregating population is possible (Montes et al., 2008). More research is necessary onoil content, oil quality/acidic composition and the influence of environment and geneticson it. Vegetable oil can be used as base for liquid engine fuel in various ways; choice ofextraction method is clearly dependent on the intended scale of activity; crucial researchand development options lay in the maximization of the transesterification efficiency atminimal cost. About this, an important issue is the improvement in the catalytic process,certainly the recovery and the reuse of the catalyst. As part of the option ofdecentralized processing units, low-cost, robust and versatile small-scale oiltransesterification designs should be developed (Achten et al., 2008).1.2.2 Selection of knowledge gaps and justificationThe above mentioned statements and knowledge gaps lead the interest and therequirement of further research that is now the case. A broad investigation appears to benecessarily addressed to all the mentioned topics; however the evident risk of beingimprecise would necessary bring to a selection. As, to date, some major knowledge gapsof the whole J. curcas production system are in the cultivation step, a deep analysis intothat will put in evidence the need of looking for growth variables in monoculture,intercropping and hedges, as well as looking for sustainability indicators, also in thesethree production systems.Growth Parameters are of major concern to understand net primary production of theplant, its potential and actual energy and water use efficiencies, its nutrientrequirements. In general, growth parameters are needed to better understand theecophysiology of the plant so to allow a full implementation of its potentials, adding therequired inputs. Concerning J. curcas growth parameters, a general overview will begiven. Firstly, a description is presented of growth parameters by plant parts: seed, root,stem/wood, leaf, flower, fruit and whole plant (Annex 1a). In this section some of thereported data are followed by annotations that would explain whether there wereexceptional conditions when the data were recorded. That is the case of seedgermination, oil quality, apical dominance and fitness. In fact, seed germination varies 31
  30. 30. 1.Introductionapparently depending on different pre-treatments; oil quality, that is its physical-chemical proprieties and its constituent composition, varies under environmentalconditions and genotype (Jongschaap and van Loo, 2009; Achten et al., 2008). To whatconcern apical dominance and plant fitness, it must be said that plant breeding is still inits infancy. Variability in plant architecture between different accessions is reported(Montes, 2008). Then, growth parameters are intended under different farmingcondition. Three cropping systems are taken into account: monoculture, intercroppingand living fence. Same growth parameters in the three cases are reported and differencesbetween values will highlight differences between farming systems (Annex 1b).The potential of jatropha oil production at a small scale and its implementation as a toolfor rural development lead to a necessary investigation of sustainability indicators. Asustainability indicator is a parameter that allows understanding the impact of an actionat different levels, mainly environmental, economic and social. This indicator should beclear enough to describe accurately the input/output ratio of each step of an entireprocess and tell whether it is more or less sustainable. In the case of the J. curcasproduction system, sustainability indicators will be identified and, firstly, divided intoagronomic, environmental, economic and social spheres (Annex 1c). These categorieswere chosen to better explain the interactions between J. curcas production systeminternal and external factors and actors. Then, an overview of sustainability indicatorswill be given for different cropping systems: monoculture, intercropping and livingfence (Annex 1d), as above considered. A deeper investigation in this sense will allowto define which one of the production systems is expected to be more sustainable. Herea right and proper specification: often the results depend on local or regional variablesthat are unable to be chosen or modified.A relief of basic parameters coming out from the analysis of growth variables andsustainability indicators and an attempt to link them together should eventually give ageneral idea of growing patterns and impacts of the different J. curcas productionsystems. 32
  31. 31. 1.Introduction1.3 Aim and objectives of the thesisJ. curcas production system is attracting worldwide Institutions, Companies andOrganizations attention, both for its oil yield suitable for biodiesel uses and for itscapability to sustainably interact with rural tropical and sub-tropical world. A lot ofprojects are now taking place in Countries all over the world to assess the feasibility ofthe set-up of J. curcas production systems and their implementation at different scalesand in relation with different realities and conditions.The present work is a part of a wider research promoted by the 1st Coordinated Call fora Transnational Research Activity under the ERA ARD net (the Agricultural Researchfor Development; Dimension of the European Research Area): “Bioenergy – anopportunity or threat to the rural poor”. Specifically, a joint consortium of academic,governmental and private institutions has proposed the interdisciplinary research andcapacity development project “Bioenergy in Africa and Central America – Opportunitiesand Threats of Jatropha and Related Crops”, thus selecting two main foci: a crop, theJatropha curcas L., and the regions, Central America and East Africa. The objective ofERA-ARD is to follow the growth and development of Jatropha curcas by monitoringimportant dynamic crop variables in different production systems and densities, andrelate them to the environmental circumstances. The opportunity that I have to join thisERA ARD proposal has included a research on crop growth and processing at TropicalStudies and Development Foundation, in Belmopan, Belize, under the scientificguidance of Plant Research International, Wageningen, the Netherlands.The main research activity was held in Belize and consisted on gathering crop growthand development data from existing plantations (LAI, yield) and to set up a field trial, inview of establishing the growth and development of Jatropha curcas L., and searchingthe links between these data to the environmental variables. The aim to share knowledgeand to set up discussions on biofuels at national and regional levels is also pursued. InBelize, the goodness of jatropha as an oil feedstock and as a tool for rural developmentat small and medium farm size will be evidenced by further research, looking at theresults in the coming years. 33
  32. 32. 2. Materials and MethodsThe work was structured and developed in two periods. The first period, from 14 th Aprilto 14th May 2009, was spent at Plant Research International (PRI) of the WageningenUniversity and Research centre, the Netherlands, and was directed to the bibliographicresearch and study of the state of the art on the jatropha plant and the whole jatrophasystem, with a focus on the cultivation. Research activities have also been undertaken inthe greenhouse, such as for leaf area index (LAI) and light interception measurements,and in the laboratory, such as for oil extraction. The second period, from 15th July to 15thDecember, was dedicated to the field research in Belmopan, Belize, at the NGOTropical Studies and Development Foundation (TSDF), with the collaboration of GalenUniversity – Applied Research and Development for Sustainability Institute (GUARD)and the University of Belize (UB).2.1 Research at PRI Wageningen, the NetherlandsDuring the research period in Wageningen twenty-six jatropha plants from four differentaccessions from Central America coded as 160 (7 plants), 176 (9 plants), 177 (7 plants)and 184 (4 plants) were grown in a greenhouse experiment for leaf area (LA)measurements and for assessing the interception capacity of photosynthetically activeradiation (PAR). The plants were five months old, they were daily watered in themorning and evening and exposed to 12 hours of light, from 7.00 to 19.00 hours. Foreach plant, cotyledons and leaves were counted, and length (L) and width (W) of eachleaf was measured; then leaf area was calculated according to the following formula: A=0.84∗ L∗W 0.99(Liv Soares et al., 2007). Jatropha light interception was also measured through a beam(SunScan Canopy Analysis System, type p.SS1), which could measure the fraction ofphotosynthetically active radiation (PAR) intercepted by the plants at different levels inthe canopy (top, middle and bottom) and in fifteen different plant densities (Table 2.1).This research phase allowed testing a methodology for LA estimation on field and lightinterception calculations that were later used for the research activities in Belize.Part of the research activity was carried out in the chemical laboratory, where oil was
  33. 33. 2.Materials and Methodsextracted from jatropha seeds and weighed. Kernels were separated from shells,smashed and mixed with the solvent: 7.5ml of hexane per round of extraction (3 times)with about 0.4g to 1.0g of kernel (van Loo, 2009, personal comm.). Table 2.1. Fifteen J. curcas plant set-ups for LAI and light interception measurements (Jongschaap et al., unpublished data) Row Plant Treatment Distance Distance Length Width Area (m) (m) (m) (m) (m2) 1 1,00 0,90 3,00 4,50 13,50 2 1,00 0,60 3,00 3,00 9,00 3 1,00 0,45 3,00 2,25 6,75 4 1,00 0,30 3,00 1,50 4,50 5 0,90 0,90 2,70 4,50 12,15 6 0,90 0,60 2,70 3,00 8,10 7 0,90 0,45 2,70 2,25 6,08 8 0,90 0,30 2,70 1,50 4,05 9a 0,60 0,90 1,80 4,50 8,10 9b 0,60 0,60 1,80 3,00 5,40 10 0,60 0,45 1,80 2,25 4,05 11 0,60 0,30 1,80 1,50 2,70 12 0,45 0,45 1,35 2,25 3,04 13 0,45 0,30 1,35 1,50 2,03 14 0,30 0,30 0,90 1,50 1,352.2 On field research in Belize, Central AmericaBelize, Central America, has a total land area of 22.966 km 2. The Country is located at17°15 N, 88°45 W, with climate characterized by a dry and a rainy (June to November)season and mean annual rainfall from 1524mm in the north to 4064mm in the south(Figures 2.1 and 2.2) (CIA World Fact Book, 2009; Belize National MeteorologicalService, 2009). Central Region, where the trials of the present research are located,shows a primary and secondary rainfall maxima occurring in June and September; inthis region, main soil type is cambisol (FAO et al., 2009). In the Country, jatropha isknown as physic nut and used for curative purposes; just recently it received moreattention by the Ministry of Agriculture and some private investors, although policies onbioenergy and market for jatropha products are lacking. 36
  34. 34. 2.Materials and MethodsField trials were performed in three areas in Belize: at Maya Ranch, a six year oldjatropha plantation; at Warrie Head, a one year old jatropha plantation; at Central Farm,a new plantation of jatropha, whose design was set up at Wageningen. These three trialswere treated and monitored trough the study of different variables: crop growth anddevelopment was monitored through the Leaf Area Index (LAI) measurement (a non-destructive method useful in yearly biomass production assessment) in all the threetrials, while yield was measured only at Maya Ranch. Measurements on seed dimensionand a germination test, other biomass production and crop development indicators, wereperformed at Bullet tree, the nursery for the jatropha seedlings destined to Central Farmtrial. Environmental variables taken into consideration were: climatic data (the same forthe three trials) and soil samples (at Central Farm trial, only). Locations ofmeteorological stations and experimental sites are shown in figure 2.3. Figure 2.2. Map of Belize and its Districts (source: m/images/belize_map.jpg). 37
  35. 35. 2.Materials and Methods Figure 2.3. Map of Belize and location of meteorological stations (Philip Goldson International Airport and Central Farm) and experimental sites (Maya Ranch, Warrie Head, Bullet Tree and Central Farm). (Source: 38
  36. 36. 2.Materials and Methods2.2.1 Climate dataClimate data collection was a kind concession from the Belize National Meteorologicalservice ( Weather variables were recorded on a daily basis(Table 2.2), through two climate stations: one station was settled at Philip GoldsonInternational Airport (17°32 N, 88°18 W) and recorded radiation (kJ m-2 d-1), vapourpressure (kPa) and wind speed (m s-1); the second one, in Central Farm (17°11 N,89°00 W), recorded Min and Max temperatures (°C) and precipitation (mm d-1). Bothstations were selected as the closest available to trials and able to record the requireddata on a daily basis. However, actual weather variables in the experimental sites mightslightly differ. In fact, trials occurred in different locations at around 100km to 140kmfrom Philip Goldson International Airport and 1km to 25km apart from Central Farmweather stations (Figure 2.3). Table 2.2. Weather variables required on a daily basis. Abbreviation Weather variable Unit Rad Radiation (kJ m-2 d-1) Tmax Maximum temperature (°C) Tmin Minimum temperature (°C) VP Vapour pressure (kPa) WS Wind speed (m s-1) P Precipitation (mm) 39
  37. 37. 2.Materials and Methods2.2.2 Maya Ranch trialMaya Ranch field trial, with an area of almost 0.5ha, is located at the 4 th mile on theCaracol Road, in Cayo District, at an altitude of 150 meters above the sea level (Figures2.4 and 2.5), in a location out of the main routes. The area is surrounded by tropicalrainforest and was formerly used as pasture for sheep, then abandoned. In June 2003,TSDF transplanted around five hundred jatropha seedlings, from seeds harvested fromwild spontaneous and backyard grown isolated trees. Jatropha was planted in thecontext of an Organization of American States (OAS) funded agro-forestry project, thatinvolved the planting of a teak plot (Tectona grandis) that still exist beside the jatrophafield, and the sowing of Habanero peppers (Capsicum sp.) and Arachis pintoii assuitable inter-crops for jatropha. To date, A. pintoii is still growing on the south-east sideof the jatropha plantation and is giving positive feedback since it is a leguminous able tocontrol weed and its cultivation does not require much labour. A. pintoii, known inBelize as Pinto peanut (English) and Maní forrajero (Spanish), is a perennial herb thatdevelops a strong taproot and forms a dense mat of stolons and rhizomes up to 20 cmdeep; there are low and highland species (up to 1400m) that show high tolerance toshade and drought. It has been used as a forage legume in intensively managedgrass/legume pastures and tree plantations, or as a ground cover in tree plantations(Cook, 1992). Its key benefits are weed control, nitrogen fixation and ability to lowersurface temperature for better soil health and moisture.The project was temporarily suspended, in 2006/2007, and the whole area was leftabandoned, until July 2009, when the jatropha field became a trial to the purpose of thecurrent research for which an inventory was done, on 22nd July. The inventory lead tothe following results: 458 plants were counted, organized in 8 rows. The distances are4m between rows and 2m between the plants within the row (1250 plants ha-1). The fieldis oriented on a south-north axis and a slight slope gradient is present in this direction,from the south side where the upper part is, to the north, at the bottom of the field(lower part). In the field, three sets of jatropha plants were recognized: i) the plants ofthe two west side rows and the last six or seven plants of each row at the bottom of the 40
  38. 38. 2.Materials and Methodsfield appeared smaller and less vigorous than the others, and they were barely bearingfruits, as a result probably of less deep soils on this side and water logging at the bottomof the field; ii) about one third of the plants towards the northern part had been prunedin 2006/2007, they presented long and straight upward branches and already somefruits; iii) the remaining two thirds consisted on the largest trees, with many branchesthat closed completely the rows and were bearing a lot of fruits in groups of three toeight racemes, A. pintoii was found growing below these plants. Two-meter high wildherbaceous vegetation was growing along the field and in the surroundings, which havebeen cut by machete twice during the growing season, in July and October 2009.Beginning a research activity on a field at that stage required some quick decisions,therefore two trials were initiated: they have been developed in separate times duringthe growing season but both of them have been set up in the same field and consideredthe same jatropha plantation. The first trial A (27th July – 10th August) focused on theharvest, while the second trial B (1st September – 1st December) on LAI measurements,as described below.Figure 2.4. Jatropha curcas L. row in Figure 2.5. Jatropha curcas L. plantation, inintercropping with Arachis pintoii, in Maya Maya Ranch, Belize, August 11th, 2009.Ranch, Belize, August 11th, 2009.For the first trial A, pruning and intercropping were identified as already existingtreatments, and two plots were selected within the field: one with pruned plants growingin monoculture (named pruned), and, the other one with not-pruned plants under whichA. pintoii was vigorously growing (named not pruned)(see annex 2, table a). Fruits 41
  39. 39. 2.Materials and Methodswere harvested and dried separately by plot. The harvest was done on 7 th July and 10thAugust, 2009, and fruits were left drying under a roof during four to six weeks. Afterthis period, the fruits have been weighed on a 100g precise scale separately as follows:7th July-pruned, 7th July-not pruned, 10th August-pruned and 10th August-not pruned.From each of the four groups, a 2% fruit sample (between 140g and 740g) was pickedand coats and seeds were separated and weighed on a 1g precise scale. From each of thefour groups, a 100g seed sample was chosen and shells and kernels separated andweighed on a 1g precise scale. Moreover, one thousands of randomly selected fruitswere opened: the number of seeds per fruit was counted and the average coat to seedweight ratio was measured on a 1g precise scale. A 100 seed sample was crushed andshell to kernel ratio was measured on a 1g precise scale.For the second trial B, two already existing treatments were identified: pruning andintercropping, and three plots were selected according to their cultural management, asfollows: intercrop/not pruned, monoculture/pruned and monoculture/not pruned (seeannex 2, table b). Pruning referred to those plants that had been pruned two yearsbefore at an height of 60cm, and, as intercrop, A. pintoii was maintained because itseasy-to-cultivate characteristics and its reciprocal benefits with J. curcas had beennoted. To record jatropha growth and development, 90 monitoring plants were selectedfor LAI measurements: 36 plants from the intercrop/not pruned plot, 18 from themonoculture/pruned plot, 36 from the monoculture/not pruned plot. LAImeasurements and estimation have been performed on 1st September, 1st November, 1stDecember, according to the methodology described in table 2.3. The choice of differentamount of monitoring plants in the plots was necessarily taken as a trade off betweenthe existing situation and the new research objectives. Furthermore, on the 1st Novemberand the 1st December, the length and the effective length of representative branches ofthe monitoring plants were measured to report the leaf production and fall off trends.Effective branch is expressed as the segment of the branch in which green leaves arestill growing. This methodology allowed to monitor two aspects of plant growth anddevelopment: first, to record the branch part actually involved in solar radiation 42
  40. 40. 2.Materials and Methodsinterception and to monitor how its length changes during the season; secondly, toobserve the plant dry matter production potential and its nutrients cycle, for whatconcern leaf production and decay, from the soil deeper layers to the leaves back to thesoil, on the superficial layers.Further calculations were made to find out intercepted solar radiation by the leaves ofthe monitoring plants, applying the following formula: 1−e−k∗LAI from Beers Law formula for light interception, first described for plants by Monsi andSaeki (1953), where k=0.68, in the case of J. curcas L. (Jongschaap, unpublished data).Table 2.3. Estimation method of the Leaf area per tree. 1Estimation method per leaf presented atExpert seminar on J. curcas L. (March 2007) (Jongschaap et al., 2007). (example unit data) Measure the length of a representative branch a 0.75 (m) Count the number of leaves on this branch b 17 (#) From the mid-section of the representative branch, select c 21.5 (cm) a representative leaf. Measure the length from the point where the leaf sheath is attached to the petiole to the opposite point of the leaf Measure the maximum width of the leaf, perpendicular d 18.5 (cm) on axis of the previous measurement Estimate how often this representative branch ‘fits’ in e 5.5 (#) the monitoring tree (e.g.5.5 similar branches) Leaf Area1 = 0.0001 m2 cm-2 * b * 0.84 * (c * d)0.99 * e 3.50 (m2 tree-1) 43
  41. 41. 2.Materials and Methods2.2.3 Warrie Head trialWarrie Head field trial, about 0.8ha large, is located just off the 9th mile of the WesternHighway, from Belmopan to San Antonio, in Cayo District, at an altitude of 45 metersabove the sea level (Figures 2.6 and 2.7). The area is a private property, surrounded byforest, and at the border of the Belize River. In 2008 the land was cleared from theprevalent graminaceae wild vegetation and ploughed. In July of the same year, in theframework of an OAS-EEP research project, TSDF planted around five thousandsjatropha seedlings of two accessions (from Guatemala and Cuba, the Cuban being calledCabo Verde), at two different spacings (3*1.7m alternated with 1.7*1.7m and 4*1m)but resulting in the same plant density of 2500 plants ha-1. Water soluble polyacrylamide(ultra-fine water-soluble polymer/acrylamide providing benefits as soil conditioningagents) in one half and effective micro-organisms (a biological product that contains amixture of beneficial organisms, such as lactic acid bacteria, yeast, and phototrophicbacteria) on the other half of the field were sprayed (Baumgart and Sengfelder, personalcomm.). On the short sides of the trial, additional jatropha seedlings were transplantedand not sprayed with micro-organisms. An irrigation system was installed. In October2008, almost two thirds of the jatropha plants were uprooted and died, as a consequenceof an extraordinary flood from the Belize River. The field was left abandoned until itsrehabilitation as a trial for the current research, in July 2009.Figure 2.6. Jatropha curcas L. plantation and Figure 2.7. Jatropha curcas L. plantationparticular of irrigation system (not in use), in (distance 1.7m between the two centralWarrie Head, Belize, August 11th, 2009. rows), in Warrie Head, Belize, August 11th, 2009. 44
  42. 42. 2.Materials and MethodsFor this trial, the preparatory inventory lead to the following results and assumptions:1476 plants were counted, the majority of them being the additional plants in the sidesof the EEP-OAS trial; these plants survived the flood because they were growing in aslight hilly area; the treatments still existing after the flood were genotype and plantspacing; at this point on time the micro-organisms previously sprayed are most likelylost and not able to interfere in the plantation; concerning the plant size, a greatphenotype variability was evident (individual height from 0.3m to 3m), but plantarchitecture appeared quite similar and suggested a strong competition for light withwild herbaceous vegetation; apparently, soil is deep. During the trial, the field wascleared by machete and bush-hogger twice, in July and in October 2009. As shown inannex 2, table c, the field is organized in four groups, divided by genotype and plantspacing in: Guatemala-(3*1.7)*1.7m2 (328 plants), Cuba-(3*1.7)*1.7m2 (370 plants),Cuba-4*1m2 (387 plants) and Guatemala- 4*1m2 (391 plants), where (3*1.7)*1.7m2spacing consists in the double row and 4*1m2 is single row. Both spatial design resultin 2500 plants ha-1. The research activity, then, started from this situation and focused onLAI measurements. Each group was divided in three sub-plots and six monitoring plantshave been chosen from each sub-plots. In total, the same 72 plants (18 per group) wereselected for LAI measurements four times in the growing season on 2nd September, 2ndOctober, 2nd November and 2nd December. The methodologies used for LAImeasurements and estimation and for effective branch length measurements are similarto the ones applied for Maya Ranch trial, as well as the formula used to calculateintercepted solar radiation.2.2.4 Central Farm trialThe trial in Central Farm was established in the framework of the project ERA-ARDBiofuels in Africa and Central America 2009-2013. The preparatory work consisted onthe experimental design finalization and on the seed retrieval. The on field activitieshave been carried out in two places: the sowing was done in a nursery at Bullet tree and,two months after, the seedlings were transplanted on field at Central Farm. 45
  43. 43. 2.Materials and MethodsThe nursery was set up at Bullet tree, three miles off the west end of the WesternHighway, in Cayo District, at an altitude of 80 meters above the sea level (Figures 2.8and 2.9). At the nursery stage data on seed dimension were taken, a germination test, LAmeasurements and destructive biomass assessment were performed, from the seed to thetwo month old seedlings. The nursery was located in a vegetable organic farm, and teakseedlings were present, too. Once a week all the plants, including the jatropha, weresprayed with a micro-organisms mixture that granted the sanity of the seedlings duringthis raising period. For the purpose of the ERA-ARD project, three seed accessions havebeen used: the Belize local one, collected in Maya Ranch, the Guatemalan G17provided by the company Biocombustibles de Guatemala and a low-toxic Mexicanprovided by the Universidad Autónoma Chapingo. The average 100-seed weight wasestablished weighing 937 Mexican seeds, 822 Guatemalan and 1000 Belizean on a 1gprecise scale. The length and the width of hundred seeds per accessions were measured,and the length to width ratio was calculated. Hundred seeds per accession were crushed,and shell and kernel were weighed separately. After these measurements, on the 23rdSeptember, 1144 seeds per accessions were sown in black cylindrical perforated plasticbags, 20cm high and 10cm in diameter, filled with local soil and rice husks (Figure 2.8);they were watered twice daily and sprayed with an EM mixture once a week. MoreBelizean seeds were sown: 288 on the same day and 1088 on the 9th October, in thecontext of the EEP project. Surveys at the nursery were done on the 30th September, 2ndand 7th October, and on the 21st October for the last sown seeds: germinated seeds andstanding plants were counted. At the nursery stage, ten plants per accessions wererandomly selected and LA measurements were performed one month after thegermination (3rd November), and at the moment of transplanting (26th November,), usingthe same methodology explained for Maya Ranch trial. On the 26th November, the sameten plants per accessions were uprooted and dried under a roof for two weeks: on the11th December dicotyledons, leaves, petioles, stems and roots were counted and weighedon a 1g precise scale. All stems and some leaves of Guatemalan (11 leaves) andBelizean (1 leaf) accessions were still green and fresh. Tap root lengths were measured. 46
  44. 44. 2.Materials and MethodsFigure 2.8. Sowing Jatropha curcas L. Figure 2.9. Jatropha curcas L. nursery, inseeds, in Bullet Tree, Belize, September Bullet tree, November 2nd, 2009.23rd, 2009.On the 26th November, 1494 jatropha plants were transplanted on a 0.6ha field at UBCampus, according to the design in annex 2, tables d and e. Additionally, 504 plantswere transplanted on the north side of the experimental plot (264 plants, 0.15ha) and onthe south (240 plants, 0.14ha) (see annex 2, table f). The field selected is located on thetop of a hilly area at Central Farm, in Cayo District, at an altitude of 60 meters abovethe sea level (Figure 2.10). The field is east to west oriented and has a pig house on theeast side, a vegetable garden and the additional jatropha on the south, orange trees onthe west and the natural forest on the north, beyond the additional jatropha strip. Thereis a slight slope gradient going downwards from south to north. Formerly, there was anorange plantation, then, nearly half of the field was covered by meadow and halfcultivated with corn (on the east side). The field has been bush-hogged, cleared andplough prior the transplanting. The transplanting followed the trial set up: a randomizedblocks design with three factors and three repetitions (see annex 2, table d). The factorswere three genotypes: Mexican, Guatemalan and Belizean; three agricultural productionsystems: monoculture, intercropping with A. pintoii and living fence; two plant densitiesof about 1250 and 2500 plants ha-1, organized in spacing of 3.7*2.2m2 and 3.7*1.1m2 inthe plot (monoculture and intercropping) and 0.25m and 0.5m in the living fence. Therewere twelve treatments per block, repeated in three blocks, resulting in a total of 36 sub-plots in the field. Moreover, six treatments repeated four times for a total of 24 segments 47
  45. 45. 2.Materials and Methodsin the living fence. In each of the thirty-six block, six monitoring plants (which had atleast 1 border row in the sub-plot) were selected and LAI measurement was performed,on the 2nd December, using the same methodology explained for Maya Ranch trial(Figure 2.11). For the statistical analysis, although, the design was reinterpreted, as, atthe time of the first LAI measurement, intercropping was not available and genotypeand plant density were the only factors. The trial was treated as a complete randomizedblock design for the analysis of the variance, though not two repetitions per three blockshave been considered but totally six repetitions for each treatment.Figure 2.10. Transplanted Jatropha curcas Figure 2.11. LAI measurements of JatrophaL. seedlings at 60 days, in Central Farm, curcas L. with technicians from the MinistryBelize, November 26th, 2009. of Agriculture and the University of Belize, an example of knowledge sharing and institutional strengthening, in Central Farm, Belize, December 2nd, 2009.On the 10th December, after the transplanting of jatropha but before A. pintoii was in theground, representative soil samples were taken from each of the three blocks at 0-20cm,20-50cm and 50-100cm depths. For the size of the experiment, six random pits perblock were prepared and samples from the three depths extracted with an auger. In total,nine soil samples were collected for different soil characteristics (Table 2.4). 48
  46. 46. 2.Materials and Methods Table 2.4. Soil variables required for 1st soil characterization. Abbreviation Soil variable Unit Sand% Sand (%) Silt% Silt (%) Clay% Clay (%) BD Bulk density (g cm-3) OM% Organic Matter content (%) C% Carbon content (%) Norg% Organic Nitrogen content (%) N Mineral nitrogen (ppm) P Available Phosphorous (ppm) K Potassium (ppm)2.3 Statistical analysisThe collected data were analysed and organized in factorial spreadsheets, Calc. Average, standard deviation and standard error of the treatmentsof each trial were calculated. Thereafter, descriptive methods have been used for climatedata, fruit yield at Maya Ranch, jatropha seed dimensions and germination rate in BulletTree; while, on data collected at Maya Ranch (LAI and effective branch length), atWarrie Head (LAI and effective branch length) and at Central Farm (LAI) the softwareAnova97 ver. 3.12 (Onofri, 1997) was used to perform the analysis of the variance. Ineach trial, monitoring plants were grouped and averaged by treatment and block (orrepetition), and the average of these groups were compared, to the purpose of theANOVA. To differentiate the means, the Duncan test with P=0.01 was applied in all thecases, except where otherwise specified. 49
  47. 47. 3. Results and discussionsOutcomes of the preparatory research in Wageningen and of the on field research inBelize, for the period July – December 2009, are presented in this chapter.3.1 Important drivers for Jatropha curcas L. growth and development and how are these for BelizeWeather variables, soil composition and nutrients availability are main drivers thatcontribute to characterize the pedoclimatic condition of an agro-ecological zone anddirectly influence crop growth and development. In the current research it was possibleto gather climate data, provided by the Belize National and Meteorological Service. Tothis purpose, the closest available climate stations were used: in Central Farm (1km to25km apart from the experimental sites), to record temperature (Min and Max) andprecipitation, and at Philip Goldson International Airport (100km to 140km apart fromthe experimental sites), to record radiation, vapour pressure and wind speed. Withregard to this, it should be reminded that this situation may have influenced somefindings of this research: in fact, it is possible that radiation, vapour pressure and windspeed values recorded in a station by the coast of the Caribbean sea and close to a largeurban area (Belize City, 70000 inhabitants) may differ from actual values occurred morethan 100km in the inland in less populated areas. Hereunder, climatic situation in Belizefor the year 2009 is summarized on a daily basis.3.1.1 Radiation and light interceptionOver the whole year 2009, radiation showed the highest mean value in May, where itreached more than 18kJ m-2 d-1; since then, mean monthly values were constantly andgradually declining to 12kJ m-2 d-1 recorded in December (Figure 3.1).To analyse resource use efficiency, solar radiation interception was measured. Lightinterception formula for jatropha has been calculated in a trial at PRI Wageningen,where measurements and calculations on jatropha at different plant densities indicatethat value of coefficient k is 0.68. However, it changes according to different LAI: infact, for LAI>7, k=0.55 and for LAI<1-1.5, k=0.75 (Jongschaap, unpublished data).
  48. 48. 3.Results and discussions Weather variables, Belize, 2009 Mean monthly values - Philip Goldson International Airport station 20 15 Radiation [kJ m -2 d-1] 10 5 0 J F M A M J J A S O N DFigure 3.1. Mean monthly values of radiation recorded at Philip Goldson International Airportmeteorological station, in Belize, 2009. Source: Belize National Meteorological Service,personal communication.3.1.2 TemperatureMean monthly temperatures have been recorded to be between 15 and 35°C, withaverage Maximum temperature around 31°C and minimum around 21°C. Both Max andMin temperature values were above the mean from April to October (Figure 3.2). Weather variables, Belize, 2009 Mean monthly values - Central Farm station 40 35 30 25 Temp. Max. [° C] Temp. Min. [° C] 20 15 10 5 0 J F M A M J J A S O N DFigure 3.2. Mean monthly values of minima (Temp. Min.) and maxima (Temp. Max.)temperatures recorded at Central farm meteorological station, in Belize, 2009. Source: BelizeNational Meteorological Service, personal comm. 52
  49. 49. 3.Results and discussions3.1.3 WaterA total yearly precipitation of 1476mm was recorded in Central Farm, where the driestperiod occurred from February to May, with about only one sixth of the yearlyprecipitation (245.1mm); while the wettest months have been June, July, August andNovember, totalling 792.2mm, equivalent to more than a half of total yearlyprecipitation. Oddly, October was recorded to be exceptionally dry, being the driestmonth with only 31.4mm of rainfall (Figure 3.3). Given this information, the beginningof the growing season of jatropha could have been most likely established in June, whenimportant precipitations occurred on the 5th (72mm) and between 16th and 20th(86.4mm). Rainfall distribution, Belize, 2009 Total monthly values - Central Farm station 300 250 200 Tot. Precip. [mm] Days of rain [#] 150 Mean Precip. [mm] 100 50 0 J F M A M J J A S O N DFigure 3.3. Total monthly values of precipitation (Tot. Precip.), number of days of rain andmean monthly precipitation (Mean Precip.) recorded at Central Farm meteorological station, inBelize, 2009. Source: Belize National Meteorological Service, personal comm.3.1.4 Vapour pressure and wind speedVapour Pressure was at lowest levels of around 25kPa in the beginning of the year, thenincreased from April, reaching maximum values between June and September when itwas recorded at around 32kPa; it finally came down to values close to 27-28kPa in thelast two months of the year (Figure 3.4). 53
  50. 50. 3.Results and discussions Weather variables, Belize, 2009 Mean monthly values - Philip Goldson International Airport station 35 30 25 20 Vap.Press. [kPa] 15 10 5 0 J F M A M J J A S O N DFigure 3.4. Mean monthly values of vapour pressure (Vap.Press.) recorded at Philip GoldsonInternational Airport meteorological station, in Belize, 2009. Source: Belize NationalMeteorological Service, personal communication.Wind speed mean values over the year were recorded to be around 3m s -1, with slightlyabove-the-mean values from January to July and slightly below-the-mean in the rest ofthe year (Figure 3.5). Weather variables, Belize, 2009 Mean monthly values - Philip Goldson International Airport station 5 4 3 Wind Speed [m s-1] 2 1 0 J F M A M J J A S O N DFigure 3.5. Mean monthly values of wind speed recorded at Philip Goldson InternationalAirport meteorological station, in Belize, 2009. Source: Belize National Meteorological Service,personal communication. 54
  51. 51. 3.Results and discussions3.2 Response of genetically different accessions to available resources in BelizeDifferent accessions have been used in the three trials: local Belizean, in Maya Ranch,and Cuban and Guatemalan, in Warrie Head, where plants were already in the ground;while in Central Farm, seeds from Mexico, Guatemala and Belize were analysed andsown. In this section, firstly, seed morphological characteristics, and, secondly,responses to agro-ecological condition in Belize are reported. Results achieved inCentral Farm trial are treated in the frame of work package 1 Crop growth andprocessing of the ERA-ARD project Bioenergy in Africa and Central America –Opportunities and Threats of Jatropha and Related Crops. Results obtained refer to seeddimension, germination, LA, fresh seedling weight and taproot length, during thenursery stage in Bullet Tree, and to LAI measurements during transplanting in CentralFarm.3.2.1 Seed dimension and weightMeasurements of length, width and hundred seed weight of J. curcas L. weredetermined for three genotypes: a low-toxic Mexican, a Guatemalan (G17), and a localBelizean accession. Guatemalan seeds were recorded among the largest for dimensions,(Figures 3.6, 3.7 and 3.8) and weight (Figure 3.9). Guatemalan average seed length wasabove 1.8cm and had 100-seed weight of 73g. Mexican and Belizean seeds had anaverage length slightly under 1.8cm and a 100-seed weight, well below Guatemalanvalues, at 58g for Mexican seeds and 55g for Belizean seeds (Figure 3.10). 55
  52. 52. 3.Results and discussions Length of jatropha seeds of three accessions, Belize, 2009 Bullet Tree, nursery 50 Frequency [# of seeds] 40 30 Mexico Guatemala 20 Belize 10 0 1.35 1.45 1.55 1.65 1.75 1.85 1.95 2.05 2.15 Class central value [cm] Figure 3.6. Length of jatropha seeds as average of a hundred seed sample per accession. Seed accessions are from Mexico (low-toxic), Guatemala (G17) and Belize (local). 2009. Width of jatropha seeds of three accessions, Belize, 2009 Bullet Tree, nursery 50 Frequency [# of seeds] 40 30 Mexican Guatemalan 20 Belizean 10 0 0.82 0.87 0.92 0.97 1.02 1.07 1.12 1.17 1.22 Class central value [cm] Figure 3.7. Width of jatropha seeds as average of a hundred seed sample per accession. Seed accessions are from Mexico (low-toxic), Guatemala (G17) and Belize (local). 2009. 56