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Notes to Broadcasters on jatropha and biodiesel:

If you have heard or read anything about biofuel production in the last year or so, you have probably heard about the plant Jatropha curcas, or simply jatropha. As our special report from correspondent Idy Sy Diop explains, jatropha can be processed into biodiesel, which is currently much less expensive than regular diesel. In Mali, a litre of biodiesel costs FCFA 150 (US$0.33 or 0.23 Euros) against FCA 510 for regular diesel (US$1.12 or 0.78 Euros).

There has been a lot of excitement about jatropha because it can grow in semi-arid regions where other crops cannot. However, the farmers from our news story are not alone in their scepticism about the plant. Many food security advocates are concerned that if farmers are pushed into growing jatropha or other biofuel plants, they may not produce enough food for their families and communities.

For more information on jatropha, please see the DCFRN script entitled Jatropha – Not Just a BioFuel Crop! (Package 80, Script 7, March 2007):

If you would like to research a local story on biofuel production, you may wish to ask some of the following questions:
-What do farmers in your area think about the idea of selling crops for biofuel production?
-If a biofuel processing plant is planned for your area, how do farmers plan to maintain their food security while also producing crops for the plant?
-If there is already a biofuel processing plant in your area, are small-scale farmers contributing to production? How do they rate their experiences in working with the processing plant (e.g. support for proper harvesting and storage, prices for crops, etc?)

6 Responses to “Notes to Broadcasters on jatropha and biodiesel:”

  1. Notes to Broadcasters on jatropha and biodiesel: Says:

    […] Clayton B. Cornell wrote an interesting post today onHere’s a quick excerptAs our special report from correspondent Idy Sy Diop explains, jatropha can be processed into biodiesel, which is currently much less expensive than regular diesel. In Mali, a litre of biodiesel costs FCFA 150 (US$0.33 or 0.23 Euros) … […]


    Due to the toxicity of its leaves, I curcas is not browsed and therefore traditionally used in protecting hedges around arable land and housing. Also due to its toxicity, I curcas oil is not edible and is traditionally used for manufacturing soap and medicinal applications. Its oil further is only suitable for industrial processing or as an energy source (See Figure 4 and Figure 5 for exploitation and processing of I curcas.

    Figure 4. Exploitation of J. curcas components (adapted from Gübitz et al, 1997).

    Burnt directly or after processing to, for example bio diesel, it could make an important contribution to the energy supply of emerging economies in general and remote rural areas in particular. Both are threatened in their development by scarcity and therefore increasing energy costs and could benefit from locally produced bio energy. Furthermore, when properly managed, handled and processed, the production of bio energy contributes to a decrease in greenhouse gas accumulation in the atmosphere.

    Figure5. Traditional use and local processing of physic nut (Jatropha curcas L.).

    J curcas potential for producing energy from marginal land without large inputs has recently created a hype of attention, resulting in the planning of huge areas of plantation in Asia, Africa and America. Predictions of productivity, however, seem to ignore the results of plantations from the 1990s, most of which are abandoned now for reasons of lower productivity and/or higher labour costs than expected (Foidl etal, 1996).

    Hence, a major constraint for the extended use of J curcas seems to be the lack of knowledge on its potential yield under sub-optimal and marginal conditions. This makes it difficult to predict yields from future plantations under sub- optimal growth conditions, the conditions where J. curcas is especially supposed to prove its value. Moreover, reliable predictions of the productivity are necessary to make responsible decisions on investments.

    This report aims to evaluate the expectations of productivity of J curcas as an oil crop under different conditions by reviewing literature, integrated with the findings of the FACT expert seminar ‘Jatropha curcas L. Agronomy and Genetics’, held in Wageningen from 26-28 March 2007 (Daey Ouwens etai, 2007).
    2. Claims on Jatropha curcas L.
    It has become clear that the positive claims on] curcas are numerous, but that only few of them can be scientifically sustained (Daey Ouwens eta!, 2007). The claims hat have led to the popularity of the crop, are based on the incorrect combination of positive characteristics, which are not necessarily present in all J. curcas accessions, and have certainly not been proven beyond doubt in combination with its oil production. Hard figures and verifiable data on various aspects of 2. curcas remain scarce, and here, the latest and most important scientifically sound information is included.

    The claims projected on J. curcas include that the crop:
    a) reclaims marginal soils,
    b) grows well under saline conditions,
    c) is drought tolerant and may have low water use (or high water use efficiency),
    d) has low nutrient requirements,
    e) is an energy crop,
    f) grows seeds with high oil contents,
    g) provides high oil yields,
    h) provides oil of high quality,
    i) requires low labour inputs,
    j) does not compete with food production, and
    k) is tolerant or resistant to pests and diseases

    All separate claims, facts and perspectives stated above, that have led to the hype around]. curcas are presented in the following sections.

    2.1 Growth in marginal soils and waste land reclamation
    In its natural distribution area, J. curcas grows in semi-arid and arid conditions (Jones & Miller, 1992; Makkar eta!, 1997; Openshaw, 2000) and in tropical humid areas, like in Guatemala (>4,000mm y’) and the northern parts of Vietnam and in Thailand.

    Under semi-arid conditions, J. curcas has a possibility for reclaiming marginal soils by exploring the soil with an adequate root system. This results in recycling nutrients from deeper soil layers, providing shadow to the soil and thereby reducing risks of erosion and desertification. Concepts for the reclamation of marginal soils are reported (Spaan et al, 2004), although its oil production is not proven to be at commercially subsistent level (Francis et al, 2005). It was demonstrated that soil structure increased significantly after J.curcas was grown for 18 months under semi-arid conditions in India; macro-aggregate stability increased by 6-30%, whereas soil bulk density was reduced by 20% (Chaudharry et al, 2007; Ogunwole et al, 2007). From 1999-2003, 2 curcas could grow well under semi-arid conditions in India at precipitation rate of 246, 145, 714, 226 and 518 mm y’ respectively over those years, and with supplemental saline furrow irrigation treatments in the dry period from October-June (Treatment 1: ECiw 9 dS m-1 Treatment 3: ECiw 28 dS m-1 Treatment 2: alternate Treatment 1 and Treatment 3). Although a growth period of 5 years is described, no production data were reported (Dagar et al, 2006).

    Rooting patterns are significantly influenced by propagation method. Plants originating from seeds and directly sown into the soil normally develop a rooting system with a thick primary tap root and 4 lateral roots, and with abundant and straight secondary roots (Heller, 1996; Soares Severino et al, 2007b), whereas plants propagated by cuttings only develop secondary roots. Growth containers in nurseries may hamper the initial growth of J. curcas seedlings if container volume is insufficient. This is caused by reduced space for root expansion and not by lower availability of nutrients in the substrate (de Lourdes Silva de Lima et al, 2007).

    Seed size (small, medium, large) significantly [LSD 0.05] influenced various variables of seedlings 90 days after emergence: seedling height (35.80, 42.74, 46.77, (3.39]; cm); rooting depth (12.80, 14.80, 17.60, [1.95]; cm); stem diameter (9.60, 10.80, 11.05, [1.11; mm); number of leaves (16, 17, 20, [2.3]; 41) and dry mailer of green biomass (1.5, 1.8,2.1, [0.23]; g seedling’) (Mailana Saturnino eta!, 2005).

    2.1.1 Waste land?
    It should be noted that the definition of ‘waste land’ is rather ambiguous, and should not be confused with the term ‘marginal soils’ or ‘marginal lands’. The term ‘waste land’ is sometimes used to indicate unoccupied areas (or areas where land ownership is not clear), whereas ‘marginal soils’ or ‘marginal lands’ are used to indicate areas with unsuitable conditions for crop production due to soil and climate constraints. Some experiences with I curcas on marginal lands are well documented (e.g. Chaudharry et al, 2007; Ogunwole et al, 2007; Patolia et al., 2007a; Patolia et al, 2007b; Shekhawat et al, 2007) and show that I curcas can he well established on marginal soils and can reach reasonable production, if proper care is given to boost plant growth in the initial grow phases and maintain production by additional inputs.

    2.2 Low water use
    Although] curcas grows in semiarid and arid tropical areas and can therefore be considered as a drought tolerant species, there is little known on water use and water use efficiency of ./ curcas as a crop. For the species Jatropha pandurifolia L. and Jatropha gossypifolia L. (Li Guo, 2002), a water use efficiency of 3.68 and 2.52 mmol 002 mmol-1 H20 was reported. This value is in the range with other oil seed species like soybean (3.90 mmol 002 mmof’ H20) and oil palm 3.95-4.42 mmol 002 mmol-1 H20).

    The organic structure of] curcas oil is depicted in Figure 6. To produce a mol of] curcas oil, 57 mol of 002 are needed in the photosynthesis process: 12 H2O+ 6 CO2 + light—> C6H12O6 + 6 O2 + 6 H2O.

    Figure 6. Organic structure of J. curcas Oil

    For the photochemical production process, J curcas oil needs 570 (≈12 g mol-1), 107 H (≈1 g mol-1) and 6O (≈16 g mol-1). A mmol of J curcas oil therefore weighs about 0.888g. At a water use efficiency of about 3 mmol C02 per mmol H20, about 57/3 = 19 mmol H20 (or 0.342 g H20) is needed to produce 0.888 g of oil. This is equivalent to 0.342/0.888 = 0.385 g water g-1 oil, or 0.385 litre water kg-1 of oil, or 385 g water kg’ oil, or is (at a density of about 0.92 kg litre-1) equivalent to 0.345 litre water litre-1 oil.

    This value of course, does not reflect the real water requirements and water use of curcas, as transpiration for plant cooling and other processes, such as transport functions, require water as well. Unfortunately, no studies were found that reveal data on actual water use and crop production, as is the case in other crops, like cereals, where the production of 1kg of grain requires roughly 1,000 litre of water.

    Increased water use by the introduction of J curcas trees, especially in large numbers, in hedges or in plantations, have not been studied so far. The effect of reduced soil evaporation due to increased shading and the presence of a mulch layer of senescent leaves and branches may still result in a negative water balance compared to the situation without] curcas, as canopy transpiration will be increased considerably. This does not have to be problematic if no other competing claims draw on the available soil water reserves.

    Potential evapotranspiration (PET) is a function of weather variables, such as solar radiation, air temperature, vapor pressure deficit and wind speed (Penman, 1956). An important variable to estimate the fraction of water evaporated by the soil and the traction of water transpired by the crop is the leaf area index (LAI; m2 leaf m2 soil). On the one hand, LAl is an indicator for the extend of soil shading, and on the other hand it is an indicator for the number of stomata cavities in the leaf area through which gas exchange (CO2 and H2O) takes place for the photosynthesis process. A large canopy (high LAI) increases the transpiration rate considerably, even above PET values, whereas large LAI values may reduce the evaporation rate from the soil to almost zero (0).

    One of the methods to estimate leaf area index of J. curcas at a given time is to consider the dimensions of singular leaves (Soares Severino etal., 2007a), leaves per plant and plant density (PD) as in the equations below:

    The above methods however, are very elaborative as they would require measuring each leaf of a number of plants individually. For calculating potential evaporation and transpiration, there is an obvious need for quick and easy assessment of leaf area index in J curcas stands. The use of Leaf Area Index meters can be considered, such as the Ll-COR Area Meters (LI-COR, Nebraska, USA) for fast, non-destructive leaf area measurements, or relations can be developed between leaf area and leaf weight, such as the Specific Leaf Area (SLA, cm2 g’) or Specific Leaf Weight (SLW, g cm’). SLA and SLW may differ between] curcas accessions and physiological age of the leaves.

    Potential evapotranspiration (PET) may differ from actual evapotranspiration (AET), as the latter depends on soil moisture availability. Besides soil properties like soil depth, water holding capacity determined by soil texture and soil organic mailer content, AFT is determined by the dimension of the root system of] curcas (rooting depth, lateral soil exploration and functional root surface), i.e. the ability of the roots to take up the available water in the soil over its rooting depth.

    Figure 7 Water relations for the growth of a 2years old J. curcas plantation at ICRISAT lndia (Wan et al, 2007,).

    In an example of a 2 year old .J curcas plantation in India, it becomes clear that soil water depletion mainly takes place when there is a substantial transpiring green canopy of J curcas leaves (March-October) (Figure 7). During the sunny and hot months (March-June) the water request from the soil (PET) can not be fulfilled, as indicated by the actual soil moisture availability (SM Depletion). Evidently, precipitation (blue bars) is not sufficient to provide the requested amount of water to fulfill PET, and most probably, soil characteristics prevent the efficient storage and release of available rain water. In this case, the reduction of crop growth and production is substantial at a level of about 50%, indicated by the ratio AET/PET.
    In another example (Figure 8), a 4 year virtual development of a J curcas canopy (LAI) for Begui, Central African Republic (40 14’ N, 18° 21’ E), with several water relations and effects on effective intercepted radiation is presented. In this example, monthly average climate data for 1961-1990 were used (New et al, 2000). Due to soil conditions, Actual El (represented by the cumulative black and green bars) is considerably lower than Potential El (represented by the black line), with exception for the wet months March-November, as can be seen in the 3’d graph from the top. At increasing LAI, a larger fraction of El is used for crop transpiration (green bars) and less for soil evaporation (black bars). In the 3Cd and 4th year, the transpiration demand of the canopy (high LAl values), is larger than Potential ET. As a result, stomata in the leaves will close and the intercepted radiation can no longer be used effectively for the photosynthesis process. In the bottom graph of Figure 8 this is represented by the reduction of the effective intercepted radiation (brown bars), in comparison to the intercepted radiation (red bars).

    Figure 8. 4 years average climate data for Bangui Central African Republic (4° 14’N 18021!S) and the development of a virtual J. curcas canopy (Ml), with effects on evapotranspiration and (effective) intercepted radiation.

    Figure 9. Yearly AFT/PET calculations for Africa based on monthly average climate data and soil characteristics (calculations by Plant Research International, 2007).

    In Figure 9, AET/PET ratios for Africa are presented by Penman-Monteith calculations based on monthly average climate data for 1961-1990 (New etal., 2000). Actual evapotranspiration was calculated by taking into account soil properties, like water holding capacity and soil depth (Batjes, 2005), but not by considering crop growing seasons.

    2.3 Low nutrient requirements
    Like any other plant, I curcas requires CO2 from the air and H20 from the soil for converting solar radiation in the photosynthesis process into functional carbohydrates (CH2O). Adult leaves of J curcas are well adapted to high radiation intensities as reported for experiments in Belize (Figure 10; Baumgart, 2007).

    Figure 10. Light response curve of J. Curcas 1. (Physic nut] fri a nursery and b plantatiOn compared to other tropical plant species fri Belüe (Baumgart 2007 fri collaboration with the Tree Physiology department ofAlberttudwigs University Freiburg, Germany).

    Photosynthesis takes place in the nitrogen containing chlorophyll, predominately present in the green leaves. Nitrogen IN), Phosphorous (P) and Potassium (K) are key nutrients needed for the structural material of which roots, stems, branches, leaves, flowers, fruits and seeds are composed (Table 3).

    The limitation of soil fertility (notable through limited availability of N, P and K in the root zone) hampers crop growth and crop production. Organic fertilizer (1 curcas seed cake) and plant density experiments (Density 1: 4×3 m (833 p1 ha-1) and Density 2: 3×2 m (1,667 p1 ha-1)) in India indicated strong effects on crop growth and production after 2-2.5 years of growth. A I curcas seed cake application of 3 t ha-1 resulted in 1.25 t seed ha-1 (Density 1; control 0.60 t ha-1) and 1.45 t seed ha’ (Density 2; control 0.75 t ha-1) (Ghosh etal, 2007). Fertilizer experiments on marginal lands in India with different levels of N (0-60 kg ha-1) and P (0-30 kg ha’) applied at planting in a 2×2 m pattern (2,500 p1 ha-1), showed that plant height (1.97 m; +23%), leaf area index (1.1 m2’ m2; ÷30%), total aboveground dry mailer (9.St ha-1; +32%), seed yield (0.44 t ha-1; +72%) and oil yield (141.7 kg ha-1; +76%) significantly increased at N45 fertilizer application in the 2 year. For phosphorous applications, P20 yielded similar results (Patolia etal., 2007a).
    In the initial growth phase after establishment of a plantation, if there is no competition for radiation, water and nutrients between plants, nutrient content in mature leaves is not significantly affected by crop density. In the competition phase, in a range from 1,667-10,000 plants ha-’, nutrient (N, P) content in leaves and nutrient (N, P) uptake from the soil was negatively correlated with plant density (Chaudharry etal, 2007). In this situation, fertilization of I curcas increased seed yield by 100%, either by inorganic or organic fertilizer (Patolia et at, 2007a; Patolia etal, 2007b). Fertilization with] curcas seedcake, the remaining bulk after oil pressing significantly increased seed yield (Chosh etal, 2007). Inoculation of] curcas with mycorrhiza significantly increased the uptake of phosphorous (P) and micro-elements (AIumnium, Zinc, Chrome, Copper, Iron and Lead) from fly-ash (mineral residue from the combustion of coal in electric generating plants) (Sharma, 2007b).

    As a perennial crop, I curcas invests a decreasing fraction of its carbohydrates into the wooden standing biomass over time, and if properly pruned, the seasonal requirements for nutrients are only needed for the seasonal formation of branches, leaves, flowers, fruits and seeds. If senescent plant material, like leaves, flowers and pruned branches are left in the field or incorporated in the soil as mulch, they are slowly decomposed, resulting in the release of the nutrients back into the soil where they are available again for crop uptake. The toxic components (phorbol esters) of J. curcas decompose quickly as they are very sensitive to elevated temperatures, light and atmospheric oxygen (NIH, 2007). Phorbol esters decompose completely within 6 days (Rug & Ruppel, 2000).

    2.4 Jatropha as an energy crop
    The harvested part off. curcas is the fruit, mostly containing three seeds. The seeds make up circa 70% of the total weight of the fruit (30% fruit coat); the mature fruits have a moisture content of circa 15%, the seeds circa 7%. The oil is stored in the interior of the seed: the kernel, which makes up circa 65% of the total mass of the seed. The moisture contents are circa 10% for the hull and circa 5% for the kernel.

    Note that in some publications it is not clear what is meant by ‘seed’: kernel and hull, which is the botanical seed (including the shell) or kernel only. Table 1 and Table 2 provide an overview of literature data on J. curcas components and dry matter distribution.
    In the presented data the gross energy content ranges between 30.1-45.8 MJ kg-1 (Table 2), which leads to the assumption that the resulting oil pressings were not very pure, as the expected value of pure plant oil is about 45 MJ kg-1. After pressing, up to 35% of fines (small impurities or sediment) may still be present in the pressing, which should be filtered out to increase the gross energy content per liter. Furthermore, the presented values for seed cake at 25 MJ kg’ seem like a meal of crushed seeds, including the oil and not a de-oiled press cake.

    Note for comparison: soy bean oil and protein content together account for about 60% of dry soybeans by weight; proteins at 40% and oil at 20%. The remainder consists of 35% carbohydrate and about 5% ash. Palm oil content is about 56%; distributed as 36% from the palm kernel and 20% from the fruit coat. Proteins in palm oil are quite low. Typical oil extraction values and global composition of other important oil seeds can be found in Table 4.

    Since] curcas is considered a low input crop, implicating a low energy use for fertilizers, tillage and so on, the life- cycle carbon dioxide emissions for bio diesel can be low, likely less than 15% compared to petro-diesel (Francis et al 2005). This efficiency can still be improved by using the seed cake that remains after pressing or extraction of the oil for energy production.

    2.4.1 Oil fraction and quality
    The seed of] curcas contains a viscous oil (Figure 6), highly suitable for cooking and lighting by itself and for the production of bio diesel. The total fraction of oil, fats and carbohydrates is circa 30 to 35% for the seed and, since 99% of the oil is stored in the kernel, circa 50 to 55% for the kernel (Table 1).
    The oil contains very little other components and has a very good quality for burning. Cetane number of] curcas oil (23.41) is close to cottonseed (35-40) and better than rapeseed (30-36), groundnut (30-41) and sunflower (29-37) (Vaitilingom & Liennard, 1997). The toxicity of] curcas is mainly based on phorbol esters and curtains, which give no pollution when burnt. The oil is also very suitable for transesterification into bio diesel (Mohibbe Azam et al., 2005). The absence of sulphur dioxide (SO2) in exhaust from diesel engines run on I curcas oil shows that the o)l may have a less adverse impact on the environment (Kandpal & Madan, 1995). As] curcas oil has a higher viscosity than diesel oil (53 versus 8 cSt at 30 °C), blending ] curcas oil up to 50% with diesel oil is advised for use in a Compression Ignition (Cl.) engine without major operational difficulties (Prarnanik, 2003)- Other publications mention much lower values for viscosity (17.1 cSt at 30°C), which would reduce the necessary blending fraction of diesel oil (Akintayo, 2004), however, conventional engines can be operated by blending bio methanol or bio ethanol (with gasoline) or bio-diesel (with diesel) from 3-20%. Some report that] curcas oil should only be used as ignition- accelerator (Forson et al, 2004).

    2.4.2 Seed cake
    Like the oil, the seed cake is toxic and therefore only suitable as animal teed after processing. The toxicity of J curcasis based on several components (phorbol esters, curcains, trypsin inhibitors and others) which make complete detoxification a complicated process. Detoxification has been successful at laboratory scale (Gross et al 1997; Martinez Herrera etal., 2006), but since the process is complicated, it is not suitable for small scale and local use. Large scale feed production, however, has to compete on a global market with high quality demands.

    Therefore, detoxification must be complete, constant and guaranteed, and is thus expected to be expensive. Hence, a successful penetration of] curcas seed cake as feed to the market at a profitable price seems doubtful.

    The main toxic components are phorbol esters, although in Mexico accessions without, or with low content of phorbol esters have been found (Rivera Lorca & Ku Vera, 1997; Martinez Herrera etal., 2006; Basha & Sujatha, 2007). The seed cake of this so called ‘non’ or ‘low’ toxic variety might be suitable for use as animal feed, but it still contains minor quantities of toxic components and resistance on the feed market towards this product is to be expected.

    On the other hand, the seed cake is nutrient rich and therefore very suitable as fertilizer (Table 3). Together with the fruit coats, the major part of the nutrients can be recycled. When no fertilizers are used, which is assumed to be the case in the use of J curcas as a low input crop, this recycling is necessary to maintain soil fertility, especially on non fertile marginal lands. Patolia (2007a) reported total aboveground dry mailer increase of 24% after 2 years N45 application, compared to N0 treatment (7.7 t dry mailer ha-’) and a yield increase of circa 100% in] curcas when 3 t seed cake ha-’ was used as a fertilizer on ] curcas stands at a density of 4×3 m (1.52 t seed ha and at 3×2 m (0.87 t seed ha-’) on marginal land (Ghosh etal, 2007). This yield increase was comparable with the increase reached with optimized mineral doses of N (45 kg ha-’) and P (30 kg ha’) for stands of 1,667 p1 ha-’ (Patolia etal, 2001a). Because of unavoidable inefficiencies, recycling nutrients will only be effective at a certain production level that allows a high dynamic nutrient cycle to take place. Initiating a plantation on low or non fertile soils therefore implies the need to use other fertilizers, at least at the start, to boost crop growth and seed production in the initial stages.

    The by-products of] curcas, such as fruit coats, seed hulls and the remaining de-oiled seed cake after pressing, may be used for organic fertilization, or for the production of more energy. Seed hulls can be burnt and the seed cake and fruit pulp can be used for the production of biogas by anaerobic fermentation (LOpez etal., 1997; Staubmann etal, 1997; Vyas & Singh, 2007). By burning, most nutrients will be lost, but after fermentation, most nutrients will remain in the effluent that can still be used as a fertiliser to recycle nutrients. To maintain I curcas production at a sustainable level, it is important to be aware that a huge amount of nutrients are removed if I curcas by-products are exploited for additional valorisation. However, the range in the reported nutrient values only comes from a few sources (Table 3), with clear variation. This indicates that environmental and management conditions have a large effect on the eventual nutrient content of the various plant parts. Soil organic mailer content decreases in a production system where nutrients are removed and not replenished by fertilization.

    2.5 High oil yield
    The positive claims on I curcas high oil yields seem to have emerged from incorrect combinations of unrelated observations, often based on measurements of singular and elderly] curcas trees. Extrapolation of such measurements to larger areas with] curcas as a monoculture crop (or in intercropping systems), ignores the growth reduction in such systems occurring from the competition for natural resources, such as radiation, water and nutrients.

    2.5.1 Flowering and pruning
    J curcas is a monoecious shrub or small free, with staminate (male) flowers and pisifllate (female) flowers on the same inflorescence (raceme). The inflorescence is a panicle, with the female flowers (about 10-20%) at the apices of the main stem and branches of the inflorescence (Figure 11). Male flowers are more numerous (about 80-90%) and occupy subordinate positions on the inflorescence. There is a strong correlation between reproduction and vegetative growth, revealed by the total number of flowers produced and the total length of the branches, bearing the inflorescence at their tips (Aker, 1997). Proper pruning (2/3 of the branch in the dormancy phase, when leaves are shed) seems to be an efficient technique to induce further branching. In India it was essential to pinch the apex of 6 months age at 0.30 m to induce branching, slower growing provenances could be cut at 0.45 m (Sharrna & Sarraf, 2007b).

    Flowering is one of the most important crop phenological stages for] curcas oil production, as the number of female flowers and their fertilization determines how many fruits and seeds eventually will develop. Flowering normally starts after a dry and dormant period and is induced and continued by prolonged periods of soil water availability, either by precipitation or irrigation. Male flowers open for a period of 8-10 days, whereas female flowers open for 2-4 days only (Prakash etal, 2007). Nutrient limitation seem to provoke the end of flowering (Aker, 1997). Continuous flowering results in a sequence of reproductive development stages on the same branch, from mature fruits at the base, to green fruits in the middle, and flowers at the top of the branch. This is problematic for mechanized harvesting.

    Small flowers and abortion of flowers and fruits may be as large as 60% or more, depending on soil water and nutrient availability. If carbohydrates are insufficiently produced, e.g. in the first period after dormancy, (lower abortion is a common phenomenon in India (Kumari & Kumar, 2001). Some experience with the application of plant hormones (auxines NAA and IM) increased biomass yields. The application of the plant hormone GA3 induced flowering (Kumari & Kumar, 2007).

    2.5.2 Seed oil content
    The high oil contents of seeds that have been observed in various] curcas accessions (Table 1) have added to the high expectations of oil yield production on a hectare base. However, the observed variation is large, whereas the genetic base is considered small in India (Basha & Sujatha, 2007). Reported values for seed oil content apply to: 1 accession from India: 37.4%: Kandpal & Madan, 1995; 10 accessions from India, 33-39%: Ginwal etal, 2004; 6 trees in India, 23-45% (kernels): Pant etal, 2006; 23 accessions from India: 26-35% Patolia etal, 2007b; 7 provenances from India: 29-39%: Sharma, 2007a; 24 accessions from India: 28-39%: Kaushik etal, 2007; 4 out of 11 provenances from India: >35%: Kumar & Kumari, 2007; 10 provenances from Indonesia: 28-34%: Manurung, 2007; 8 provenances from India: 28-36%: Shekhawat etal., 2007 (See Table 1).

    Without any doubt, high oil content of the seeds is an important crop characteristic, but if seed size, the number of seeds, or the number of fruits per tree (or per square meter) is not accurately accounted for, oil yields per hectare are easily overestimated. In the same way,] curcas accessions that produce large seeds, and a high number of seeds or fruits per tree (or per square meter), may be low in oil production per hectare if seed oil content is low. In the ideal situation with a high number of seeds per plant (or per hectare) in combination with high oil content per seed, it is justified to relate high oil yields with I curcas. All studies that express seed yield (or oil yield) per tree should therefore be carefully analyzed and valued.

    2.5.3 Seed yield
    Seed yield in I curcas varies widely, which is logic for a crop that can grow under many different conditions. For hedges in Mali, the values of 0.8 to 1.0 kg dry seed per meter of hedge is often cited (Henning, 1998), but this range is so small that it is unlikely that these values include really different conditions (climate, soil) or situations (e.g. age, number of plants m’, etc.).

    Seed yield can also be highly variable within plantation stands, varying for example from 0.2 to more than 2 kg per tree (Francis etal., 2005). This variability in yield is in contrast with the genetic variability, which is rather small in Indian germplasm (Basha & Sujatha, 2007).
    Recently published low production figures mostly apply to young I. curcas plantations of 1-2 years old. I curcas is known to grow and produce with a minimum water availability of 500 to 600 mm Sc’, with a realistic yield of probably less than it seed ha’ (Euler & Gorriz, 2004). Optimal growth seems possible with a water availability of 1,200 to 1,500mm y’, if it is well distributed. In Brazil, at different plant spacing and with drip irrigation, yields were 335 kg seed ha’ (4x3m; 833 p1 ha’; after 12 months), 190 kg seed ha’ (8x2m; 625 p1 ha’; after 9 months) and 56 kg seed ha’ (8x2m; 625 p1 ha’; after 7 months) (Mattana Saturnino etal, 2005). In India, experiments on marginal soils yielded 0.60 (control, 833 p1 ha’) to 1.45 t seed ha’ (1,667 p1 ha1) after 2.5 years (Ghosh etal., 2007). In Indonesia, the first year’s yield of a plantation resulted in ca. 3.0 t seed ha’ (Manurung, 2007). Yields were reported ranging from 3.2 to 4.1 t seed ha’ for the first year after planting for six different locations of rain fed marginal lands in Uttar Pradesh (India), unfortunately without detail on growth conditions and management (Lal etal, 2004).

    Note: For reported yield values it is not often clear if values apply to fresh or dry weight (and how dry weight is expressed), and if the whole fruit, the complete seed with its kernel, or the kernel alone is meant. The oil contents in .1. curcas seeds show a high variability (Table 1) and, since the oil content seems not to be related with the seed yield (Patolia etal, 2007a), this variability may be a good criteria for selection.

    2.5.4 Genetic and environmental effects
    Genetic and environmental factors have significant impact on oil yield production factors. Within the (perhaps small) genetic resource base of 24 ./ curcas accessions from Haryana state (India), environmental factors were predominant over genetic factors, although seed size, and oil content and seed weight could be genetically clustered and significantly differentiated (Kaushik etal, 2007). In another (small) sub-set of 10] curcas accessions from central India, seed oil content was significantly correlated (* * at 0.01 level) with seed weight (0.792* *), stem diameter (O.836**) and total leaf area (0.883* *) (Ginwal etal, 2004). In a range from 400 to 1,000 m elevation, that might have a relation with temperature, altitude had a significant positive effect on various oil yield components, including the number of branches per tree (+2), number of fruits per branch (+12), number of fruits per tree (+100) and number of seeds per tree (+300), but a significant reduction was observed in kernel oil content (43.10 at low vs. 30.66% at higher elevations) (Pant etal, 2006). Kernel oil content was significantly higher in soils that had not been used for arable farming before (42.3 vs. 35.0%), but no information on soil fertility variables were presented (Pant etal, 2006). Reported values of seed weight vary considerably for different] curcas provenances (Table 1). Reported genetic factors included seed weight and seed oil content (Ginwal etal, 2004; Kaushik etal, 2007), although 42 Indian accessions of] curcas showed modes levels of genetic diversity with 400 RAPD (Random Amplification of Polymorphic DNA; genetic fingerprinting technique) 42% molecular polymorphism) and 100 ISSR (Inter-Simple Sequence Repeat: genetic fingerprinting technique) (33.5% molecular polymorphism) primers (Basha & Sujatha, 2007). In other tests with 23 selected provenances from 300 collected provenances in India, 8-10% (AFLP; Amplified Fragment Length Polymorphism; genetic fingerprinting technique) and 14-16% (RAPD) polymorphism was found (Reddy etal, 2007).

    2.5.5 Seed yield projections
    Projections for more mature plantations lack a sound scientific basis, or worse, are based on wrong assumptions. Values from 0.4 to 12 t seeds ha’ per year were projected for mature plantations (Jones & Miller, 1992), but no information on the background of this variation was given. A range of 0.5-12 t ha-’ and 5 t ha-’ as a reasonable estimate for good soil conditions under rainfall conditions of 900-1,200 mm y’ was reported without evidence (Francis etal, 2005; Daey Ouwens etal, 2007). Openshaw (2000) anticipated yields of 7.5 t fruits ha-’ y’ (circa 5 seed ha-’) for an established stand under good growth conditions with sufficient water, but without presenting the scientific basis.

    From plant physiological point of view, plant growth is a function of intercepted photosynthetically active radiation (PAR), temperature and water availability, provided that nutrient levels are at sufficient level. Based on the global distribution of these variables, Net Primary Production (NPP, g C m2 yt) can be calculated as the production of all types of plant biomass in a year (Figure 12).

    Looking at latitude distribution of Net Primary Production and the] curcas belt (roughly between 30° N and 35° 5, Figure 13), simulated values for NPP vary between 200 and 1,000 g Cm-2 y’ (equal to 2 to lot C ha-’ y’). As the average carbon (C) content of plant material is about 47.5% of total dry mailer (Ho 1976), resulting NPP ranges between 4.4-22.2 t dry matter ha-’ y-’ in the] curcas belt, depending on longitude and the applied simulation model.

    Assuming a mature! curcas stand that intercepts all incoming radiation, 25% of dry nailer is accumulated in wood (stems and branches), 25% in leaves and 50% in fruits (Openshaw, 2000). These values for dry mailer distribution among plant organs are indicative values and are debatable, as no proper growth analyses have been reported so far. A theoretical distribution of dry nailer distribution is presented in Figure 14, where (over years) relatively less dry matter is assigned to roots and stems, and more to leaves and fruits.

    However, if a distribution of 30% fruit coat and 70% seeds is assumed, as found by various authors (Table 1), seed production for a mature! curcas stand may range between 1.5-7.8 t dry seed ha’ y’. An assumed seed oil content of 35% would result in 539-2,120 kg extractable oil ha-’ y’. An extraction efficiency of 75% would lead to 404-2,040 kg oil or (assuming an oil density of 0.92 kg litre’) about 439-2,217 litre oil ha’. In the above example, the Harvest Indices (HI) for various components per kg dry seeds are:

    • Hl,, 035 kg’
    • 0.09 kg’
    • HI,IL,L,M, = 0.10 litre kg’

    Note that these projections apply for the situation that all incoming radiation is intercepted (which is not the case if there is a distinct growing season (green leaf period) for I curcas), and that local differences may result from genetic and environmental conditions that affect dry nailer distribution among plant organs.

    The argumentation above may explain the difference with a high yielding oil crops such as oil palm (production up to 5-6 toil ha’ y’), that gradually decreases dry matter assignment to leaves and stems over time (Tinker & Smilde, 1963; Gerritsma & Soebagyo, 1999). The dry mailer assignment to the oil seed is more positive for oil palm. The continuous high value for leaf area index (LAI) in oil palm guarantees year-round full interception of incoming radiation, and secures high production potentials (Gerritsma & Soebagyo, 1999). The oil palm belt, roughly situated between the latitudes of 10° N and 10° 5, shows highest radiation and temperature levels, resulting in a higher NPP potential in comparison to other latitudes (See Figure 12 and Figure 13). Furthermore, the humid climate conditions in oil palm production areas prevent water shortage situations, and the acknowledgement of the importance of soil fertility (oil palm production on fertile soils) result in higher oil production values for oil palm than from I curcas.
    However, .1 curcas potential for annual oil production (439-2,217 litre ha’) is high in comparison with values reported for other oil producing crops, like soybean (375 litre ha’), sesame (575 litre ha’), sunflower (800 litre ha-’), rapeseed (1,000 litre ha-’) and castor (1,200 litre ha-’), although these values may double or triple in the case of double or triple growing seasons in a year. One of the competitive aspects of I curcas is the perennial growth (with its positive effects on soil conservation), with a relative high Harvest Index for seed (Hl,EE,=O.35) and oil (Hl,L0.1O).
    2.5.6 Yield improvement
    To increase oil yield, agronomic practices and crop management should be aimed at optimizing the use of (natural) resources like solar radiation, water and soil fertility, and the prevention of pests and diseases.

    In the initial growth phase after establishment of a plantation, when there is no competition for radiation, water and nutrients between plants, seed yield per plant and seed yield on an area base is not significantly affected by crop density. In the competition phase, seed yield per plant is negatively correlated with plant density, but seed yield on an area base is positively correlated with plant density (Chikara etal., 2007). As a comment to the latter observations, it should be noted that plant density may not be a fully explanatory variable, as additional branching in low plant density situations, may increase the number of fruits per area base considerably. Data on branching however, were not reported for this situation (Chikara etal., 2007).

    A prerequisite for better growth and production may be the presence of arbuvescular mycorrhiza in the soil for the uptake of phosphorous (P) which have been reported to reduce P deficiency on marginal soils (Sharma, 2007b).

    The dry mailer distribution ratio between fruit coat and seeds might be good selection criteria for increasing seed yield, as well as finding.! curcas accessions that assign more dry matter to fruits instead of stems and leaves. Since the oil content seems not to be related with seed yield (Patolia etal., 2007b), this variability may be a good criteria for selection as well.

    2.5.7 Summary
    Recently published low production figures mostly apply to young.! curcas plantations of 1-2 years old. Currently observed yields range from 0.6 to 4.1 t seed ha’ if proper attention is given to crop establishment, water and fertility levels. Depending on crop growth conditions, such as water, nutrient availability and the absence of plagues and diseases, maximum yields of 7.8 t seed ha-’ are projected for mature stands. Depending on geographical distribution, I curcas stands may reach maturity and full production about 3-4 years after planting. Younger stands have appreciably lower yields due to inefficiencies in radiation interception and the assignment of dry matter to standing biomass instead of the harvestable parts, the fruits and seeds. Decreasing productivity has been reported for aging stands, but it is not clear whether this is a general phenomenon or not. A reason for declining productivity could be the increasing pressure of fungal diseases, likely to occur under high rainfall and humid conditions. Pruning and use of fungicides might abate the decline in yield, but quantitative data are not available.
    Data on production levels under well defined sub-optimal growth conditions are largely absent. This makes it practically impossible to predict future production potentials from marginal land, while especially the production on marginal land can contribute to the development of rural areas without competing much with food production and biodiversity. It can be stated that the hype in.! curcas oil production is not sufficiently supported by hard data on crop production, well controlled or optimal management production conditions, and environmental impact (Achten et a!, 2Q07; Muys etal, 2007).

    2.6 Oil recovery

    For .J curcas oil extraction at small scale, various oil presses have been developed and modified from presses for other oil seed crops. They have in common that they vary in design and are non-standardized, as they were originally developed for other (edible) seeds and need to be optimized for.! curcas seeds. Biè/enberg Ram (Hand) Presses handle 7-10 kg seed h and spindle presses handle 15kg seed h’ (Mbeza etal, 2002). Commercially available press{ng systems claim processing 500 kg seed h-’ (Figure 15).

    The recoverable oil fraction is clearly affected by pressing technology. For hand powered small scale pressing (such as the B/elenberg (Hand) Ram Press), an oil yield of only 19% of the seed dry weight or 30% of the kernel was reported (Foidl & Eder, 1997; Augustus etal, 2002; Akintayo, 2004; Henning, 2004; Francis etal, 2005), which is about 60% of the total extractable amount. With mechanized pressing equipment about 75% of the oil can be recovered. Commercially available pressing systems used for large-scale de-oiling of e.g. soybean and rapeseed reach up to 90%.

    Modern extraction techniques can substantially raise the extractable oil fraction. Industrial extraction with organic solvents (mainly hexane) yield near 100% of the oil content, while extractions on water basis can yield from 65-97% of the oil, depending on, (e.g.) the composition of the extract solvent, the acidity (pH) and the temperature of the solvent (Shah etal, 2004; Shah etal, 2005).

    2.7 Low labour input
    It is unverified that J. caress oil production requires minimum amounts of labour input. The claim that it would be an excellent choice in areas that have low labour capacity should therefore be strongly defied. Also, the noble thought of generating income in HI V-affected communities by planting! curcas as a low labour input crop, cannot be sustained. In order to prepare the land, set-up nurseries, plant, irrigate, fertilize, prune, harvest and process the seeds for oil production, labour availability and labour costs are elements to be seriously accounted for, especially in the P’ year for establishment of the crop. Labour needed for crop maintenance and harvest will increase to substantial levels in the subsequent years. The required labour input may be at a modest level only when I caress is used for combating desertification, conserving water and preventing soil erosion, because crop maintenance, harvesting and processing is not required. The use of I caress in Contour Vegetation Barriers (CVB) as an example of such a soil and water conservation measure in Burkina Faso and Mali – West Africa (rainfall up to 1,200 mm has been found effective. The labour requirement for 100 m CVB was calculated as 30 man-days per year (Spaan et a!., 2004). The locally available J. caress genetic resources however, were not suitable to integrate the soil and water conservation function with oil production at the same time (WiesenhUtter, 2003). Labour input for crop maintenance, (weeding, irrigation, fertilization, pruning) increased from 22 person days ha-’ y’ in the 1” year, to 70 person days ha-’ y’ (including harvesting) in the 6° year (Sharma & Sarraf, 2007c).

    2.8 Competing claims between food and bio-fuel production
    The raised expectations of! caress oil production may result in a doubtful incentive for farmers to change from traditional or commercial food production to bio-fuel production. In both cases, farmer’s maV risk their food security or income stability.

    Until! cat-c-as oil production has proven to be sustainable at a reasonable level, with transparent and fair market opportunities, or by opportunities for local use of I caress oil in lighting, electricity, cooking and mechanization, risk avoidance strategies in crop production may be required. An option would be to integrate! caress production in traditional farming systems, such as intercropping or hedge production.
    If ./ caress sustainable oil production is considerably raised and stable, farmers may choose to dedicate their soils, labour efforts and money in I caress production. The impact of such a shift from food production to bio-fuel production is unpredictable, as it depends on the availability of natural resources and the competition emerging from the incorporation of this crop in the food production systems.

    2.9 Tolerance to pests and diseases
    The assumed tolerance of! caress to pests and diseases that have been reported are merely based on observations of singular and solitary trees, and do not apply in general to I caress grown in plantations. The toxic characteristics of! caress, caused by constituents in leaves, stems, fruits and seeds may suppress damaging effects from some predators, but certainly not all. In plantations, especially under humid conditions, serious problems have been reported with fungi, viruses and the attack of insects (Sharma & Sarraf, 2007a). Observed diseases are Collar rot’ (caused by Maeropp/zominsp/isseolihsor Rhüoctoniabatst/co/s) at juvenile stages or by water-logging at adult stages, Leaf spots (caused by Cereospora Jatropha-curcas, He/ininthosporiam tetramers or Pests/ot/opsis spp.), Root rot (caused by rasariam monil/forme) and damping off (caused by Phytophotors spp.).

    2.10 Nutritive potential and toxic constituents
    Great variation is observed in seed kernel fraction (Makkar etal, 1997: 53.9-64.0%; 61.3±3.1%) relative to the whole seed (Makkar etal, 1997). Within the kernel there is subsistent variation between provenances in crude protein (19-31%; 26±3.2%), lipid (43-59%; 53±4.8%), neutral detergent fiber (3.5-6.1%; 5.0±0.87%) and ash (3.4-5.0%; 4.2±0.52%) (More observed values in Table 5). Gross energy content of the kernels ranged between 28.5-31.2 MJ kg’ (30.1±0.8 MJ kg’) (a.o. Makkar etal., 1997) to 45.8 MJ kg’ (Forson etal, 2004), mostly as a result of the debris fraction in the oil after pressing. See Table 2 for more values.

    A wide variation in toxic constituents, e.g. trypsin inhibitor in defatted kernels (18.4-27.5 mg g’; Makkar eta!.,1997) was observed, as well as a wide variation in saponins (1.8-3.4%; Makkar etal, 1997) and phytate(6.2-10.1%; Makkar etal., 1997). Phorbol esters are predominantly present, but are sometimes at low levels or not detected in provenances from Mexico. Phorbol ester content ranged from 0.87-3.32 mg g’ of kernel weight in 17 provenances (Makkar etal., 1997; 3.85mg g-’: Martinez Herrera etal., 2006).

    Much attention to various aspects and tests of toxic components (phorbol esters and curcains) in J. curcas was reported at the ‘Jatropha 97’ Symposium in Managua, Nicaragua (Chapter 4 in Gubitz etal, 1997), including experiences for using proteins from toxic and low toxic’ J. curcas seeds for livestock feed (Makkar & Becker, 1997). Toxic constituents were found to be effective against a wide variety of pests (Solsoloy & Solsoloy, 1997; Rug & Ruppel, 2000). A 100% mortality rate was obtained against mosquito (CulexquinquefasciatusSay), when petroleum extracts of I curcas leaves were used as a larvicide (Karnegam etal, 1997).

    Successful detoxification processes included moist heating at 121 °C for 25 minutes to inactivation of trypsin inhibitors, slightly decreasing phytate levels by irradiation at 10 kGy, and reducing saponin contents by ethanol extraction and irradiation (Martinez Herrera stat, 2006). Extraction with ethanol, followed by treatment with 0.07% NaHCO3 decreased lectin activity considerably. This treatment also decreased the phorbol ester content by 97.9% (Martinez Herrera stat, 2006). Phorbol esters of] curcas decompose quickly as they are very sensitive to elevated temperatures, light and atmospheric oxygen (NIH, 2007); they decompose completely within 6 days (Rug & Ruppel, 2000).

    2.11 Superior or elite J. curcas accessions
    It is unverified that superior or elite accessions of] curcas exist, or that well performing I curcas provenances will perform successfully when moved to other locations with different environmental circumstances (soil, climate) and management. I curcas still is a wild species, and genetic identification of provenances and testing them in different locations and conditions should be priority research for the coming years.

    Provenance trials with local] curcas accessions are reported for lndia (Ginwal eta/., 2004; Lal eta!., 2004; Basha & Sujatha, 2007; Kaushik stat, 2007; Patolia stat, 2007b), and for various accessions, mainly from Africa (Makkar stat, 1997). They reveal that the genetic base of] curcas provenances from India is quite small (Basha & Sujatha, 2007), that significant differences in plant morphological aspects (plant height, leaf area index, stem girth, number of primary-secondary-tertiary branches) and yield contributing factors (fruits plant’, seeds plant’, seed weight and oil%) could be distinguished between provenances (Patolia stat, 2007b).

    3. Conclusions
    This study Claims and Facts on Jatropha curcas L.’ has revealed that the wild species] curcas has great potential and value to be exploited in its natural environment of semiarid and arid conditions in the tropics. The traditional and successful application of curcas includes functions like soil water conservation! soil reclamation, erosion control, living fences, firewood, green manure, lightning fuel and local use in soap production, insecticide and medicinal application at modest scale. For these applications, the majority of claims stated in section 2 (page 5) can be sustained by literature findings.

    However, as soon as] corcas is related to high oil yield production, a claim which in itself is not backed up by any scientific findings so far, (especially not at large scale), a risk warning should be given about the validity of these claims. Especially the claims of low nutrient requirements (soil fertility), low water use, low labour inputs, the non existence of competition with food production, and tolerance to pests and diseases are definitely not true in combination with high oil yield production. In the sections 3.1 to 3.4, the main conclusions drawn from facts in relation to these claims are summarized.

    Note: It has become clear that there is need for an analytical framework that could be applied to] curcas tillage systems and] curcas applications. Such an analytical framework should provide a clear scope of the] curcas potential in different environments and social settings. In Chapter 4 (page 29 and further), elements for such a framework are presented, which could help to understand the impact of] curcas for different types of applications, and at different production scales.

    3.1 Scientific base to support claims
    • The claims hat have led to the popularity of] curcas as an oil producing crop, are based on the incorrect combination of positive characteristics, which are not necessarily present in all] curcas accessions, and have certainly not been proven beyond doubt in combination with its oil production.
    • A major constraint for the extended use of] curcas seems to be the lack of knowledge on its potential yield under sub-optimal and marginal conditions. This makes it difficult to predict yields for future plantations under sub-optimal growth conditions, the conditions where] curcasis especially supposed to prove its value.
    • The productivity of] curcas envisages a severe lack of quantitative data, and more specific, a lack of description of conditions under which data were collected.
    • It should be noted that the definition of ‘waste land’ as a possible place for ] curcas growth and production is a rather ambiguous term, and should not be confused with the term ‘marginal soils’ or ‘marginal lands’, which indicate areas with sub-optimal environmental (climate, soil) growth conditions.
    • All studies that express seed yield (or oil yield) per tree (and not per area base, e.g. per hectare) should be carefully analyzed and valued, to avoid misinterpretation and the negligence of competition effects for radiation, water and fertility, especially in the situation of plantations and in intercropping systems.
    • For reported yield values it is not often clear if values apply to fresh or dry weight (and how dry weight is expressed), and if the whole fruit, the complete seed with its kernel, or the kernel alone is meant.
    • There is a need for proper growth analyses for] curcas tillage systems, revealing the distribution of dry matter to roots, stems, leaves, fruits and seeds under different circumstances. Especially more knowledge on leaf area index development is needed for calculating radiation interception and transpiration requirements.

    3.2 Production areas and yield
    • I curcas can be well established on marginal soils and can reach reasonable production, if proper care is given to boost plant growth in the initial growing phases and to maintain production in subsequent years.
    • Recently published low production figures mostly apply to young] curcas plantations of 1-2 years old. Currently observed yields range from 0.6 to 4.1 I seed ha’.
    • Reliable predictions of I curcas productivity are largely absent, but are required to make responsible decisions on investments.
    • Based on plant physiological variables and depending on growth conditions, such as radiation, water, nutrient availability and the absence of plagues and diseases, and assuming a dry mailer distribution of 25% wood/branches, 25% leaves and 50% fruits (30% fruit coat, 70% seed), maximum yields of 7.8 t seed ha’ are projected for mature I curcas stands, An assumed seed oil content of 35% would result in 539-2,720 kg extractable oil ha’ y’. An extraction efficiency of 75% would then lead to 404-2,040 kg oil, or (assuming an oil density of 0.92 kg litre’) about 439.2,217 litre oil ha’.
    • In the above example, maximum Harvest Indices (HI, based on dry matter production) for various yield components are HI,EE,0.35 kg kg’, kg kg’ and Hl,IL,LuME0.10 litre kg’.
    • The dry mailer distribution ratio between fruit coat and seeds might be good selection criteria for increasing seed yield, as well as finding curcas accessions that assign more dry matter to fruits instead of stems and leaves.
    • Since the oil content seems not to be related with the seed yield, this variability may be good criteria for selection.
    • To estimate water use, water use efficiency and determine actual evapotranspiration (AET) over potential evapotranspiration (PET) (and the growth reduction factor AET/PET), there is a need for quick and easy assessment of leaf area index (LAI, m’ leaf m2 soil) in I curcas stands.

    3.3 Toxicity and exploitation of by-products
    • The toxicity of] curcasis based on several components (phorbol esters, curcains, trypsin inhibitors and others) that are present in considerable amounts in all plant components (including the oil), which make complete detoxification a complicated process.
    • Since the detoxification of] curcas organic material is such a complicated process, it has —so far- only been successful at laboratory scale, and seems not to be suitable for small scale and local application.
    • Like other I curcas plant components, the seed cake is toxic and the prospect for successful penetration of the feed market with a detoxified product seems small.
    • The seed cake (either as remainder of the pressing process, or as a complete meal) is nutrient rich and therefore very suitable as fertilizer.
    • Phorbol esters of] curcas decompose quickly as they are very sensitive to elevated temperatures, light and atmospheric oxygen (NIH, 2007); they decompose completely within 6 days (Rug & Ruppel, 2000).
    • To maintain I curcas production at a sustainable level, it is important to take notion of the huge amount of nutrients that are removed from the soil if ./ curcas by-products are exploited for additional uses, including the bio-refinery concept.
    • 3.4 Socio-economic aspects
    • It is unverified that] curt-as oil production requires minimum amounts of labour input. The claim that it would be an excellent choice in areas that have low labour capacity should therefore be strongly defied.
    • Continuous flowering results in a sequence of reproductive development stages on the same branch, from mature fruits at the base, to green fruits in the middle, and flowers at the top of the branch. This is problematic for mechanized harvesting.

    4. The sustainable livelihoods approach (SLA) for small scale farmers
    4.1 Introduction
    It has become clear that there is need for an analytical framework that could be applied to analyze I curcas tillage systems and other] curcas applications. Such an analytical framework should provide a clear scope of] curcas potential in different environmental and social settings.

    In order to assess the usefulness of] curcas for different applications and in these different settings, with the aim to improve the lives of poor people in marginal areas, it is important to have this analytical framework that allows comprehending the drivers for success and evaluating effects on various aspects of small scale farmers. This section describes the Sustainable Livelihood Approach as such an analytical framework applied for different I curcas systems.

    4.2 Analytical framework
    The sustainable livelihoods approach draws on a framework developed in the late 1990s. This framework brings together conceptual insights based on research conducted in rural and urban locations since the late 1980s — in a way, it can be perceived that the SLA summarizes several years of thinking about poverty and vulnerability (Chambers, 1987; Chambers & Conway, 1992; Sen, 1997; Moser, 1998; Bebbington, 1999).
    Here a sustainable livelihood is defined as:
    comprising the capabilities, assets (including both material and social resources) and activities required for a means of living. A five/Mood is- sustainable when it can cope with and recover from stresses and shocks, and maintain or enhance its capabilities and assets both now and in the future, while not undermining the natural resource base (Carney, 1998).

    The central concept of the SLA is that individuals and households rely on a basket’ of assets which form the basis of their activities (or livelihood strategies). The following 5 assets are distinguished (Figure 16):

    • Human assets; such as health, skills, religion and education.
    • Physical assets; such as infrastructure, housing, etc.
    • Social assets; such as participation in social networks and political voice to influence decision-making — in other words, representation and influence; often seen as the most critical asset, as it mediates access to the other assets.
    • Financial assets; such as earnings, savings, access to credit, remittances, etc).
    • Natural assets; such as natural resources, both private — land — and common environmental resources.

    Social capital in the sense of voice and representation to influence policy is what poor and marginalized groups often lack. Strengthening civil society and participatory democracy are closely related to increasing their social capital.

    Livelihood strategies are a rational response to the external context, and are developed on the basis of the available assets. Increasing the asset-base (and therefore increasing the capacity to respond to external stresses and shocks and improve livelihoods) is the result of accumulation strategies. This, in turn, means that in order to identify priorities and feasibility for action it is critical to examine the asset-base of different individuals, households and communities. Food security, measured in terms of the nutritional status of the livelihood members, is viewed as one of the outcomes of livelihood strategies.

    4.3 Key message
    The key message of the SLA is that people manage risk and cope with shocks and hazards (described in the vulnerability context) actively and in a variety of ways. The main role for policy is therefore to raise the asset status of poor individuals and households, and in this way strengthen their own inventive solutions rather than substitute for, block or undermine them. Policies and institutions can therefore play a critical role in enabling and encouraging strategies that improve livelihoods. But at the same time, many policies and institutions can disable and discourage such improvement. Understanding the role of policies at the local, national and international levels is essential to promote change, as is supporting the development of accountable and competent local institutions.

    4.4 Examples
    To illustrate the application of the Sustainable Livelihoods Approach, 2 examples for I curcas application are presented. The first example comprises the use of I curcas production as merchandize commodity for economy reasons in Brazil, and the second example is the use of J. curcas production as a catalyst for rural development, with Tanzania and Uganda in East Africa as a special case (Table 6).

    When the asset-base is low and external shocks and stresses too strong, live hood strategies can be defined as survival’ or coping’ strategies: people still try and make the best possible use of their assets, but are forced to deplete them in the process. A typical example of this is when small-scale farmers are forced to sell seed or livestock because of declines in production or in farm-gate prices; or when poor urban-based households must take children out of school because they need whatever income they can generate.

    The external context is defined in the framework as the ‘vulnerability context’. Vulnerability is important: it describes the fact that many people are not set in static positions, but actually move in and out of poverty at different times in their lives.
    Depending on their personal circumstances (for example, loss of income due to illness, loss of support from family and community, perhaps through divorce or widowhood, etc.), the circumstances of their household (often a large number of dependants compared to active members — this may be part of the natural life cycle of the household, or due to illness and death of the ‘productive’ age group, as is often the case with HIV/AIDS; etc.), external sudden shocks (natural disasters, conflicts, etc) and longer-term trends (decline in natural resources in relation to population density, policy changes in relation to agricultural markets, public services, etc.).

    4.4.1 Top down support in Brazil
    The government of Brazil has committed itself to promote bio diesel production through political intervention (Law 11.116/05, Decrete 5.297/04). This action can be described as Top dow

  3. taiwo Says:

    physiochemical Properties and Fungitoxicity of the essential oil of lime

  4. fadhli Says:

    can u give me information about destructive analysis for jatropha? i appreciete your cooperation.
    thank u.

  5. jatropha gossypifolia Says:

    […] … close to New Zealand) banned Jatropha gossypifolia (purging gossip nut) as invasive and …Farm Radio Weekly Farm Radio Weekly Archive Notes to …For the species Jatropha pandurifolia L. and Jatropha gossypifolia L. (Li Guo, 2002), a water use […]

  6. Storage Urmston Says:

    How long do you spend a day coming up with stuff like this?

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