Assessment of benefits and risks of growing Jatropha (<Emphasis Type="Italic">Jatropha curcas</Emphasis>) as a biofuel crop in sub-Saharan Africa: a contribution to agronomic and socio-economic policies

In sub-Saharan Africa (SSA), the main goals behind the development of a biofuel industry are employment creation and income generation. Jatropha (Jatropha curcas L.) has emerged as a candidate for biodiesel production. It is a non-edible oil producing, drought-resistant plant that can be grown on marginal land with limited water and low soil fertility. However, these are also attributes that typify weedy and invasive plant species. Adding to these concerns are the general questioning of whether biofuel production will reduce Greenhouse gas (GHG) emissions globally. Currently, there is limited information on the potential invasiveness of many biofuel crops, and in particular, the potential risks of cultivating Jatropha. This paper aims to assess the benefits and risks, especially risks, of growing Jatropha for biodiesel production. Jatropha should be screened through a science-based risk-assessment procedure to predict the risk of becoming invasive before it is released for large-scale commercial cultivation. The net GHG savings can be achieved through the cultivation of Jatropha, considering two main factors: no land-use change and crop management without chemical fertilization.     

Current situation and prospects of Jatropha curcas as a multipurpose tree in China

This paper reviews the current status of studies on Jatropha curcas in China. Jatropha curcas has been grown in China for more than 300 years. It is mainly distributed in the southwest from the Yunnan-Guizhou Plateau to the hot and dry Three-River Valley with hot monsoon climate and the southeast in the provinces of Fujian, Guangdong, Guangxi, Hainan and Taiwan along the coast. The regions where it occurs have annual rainfall >500 mm and average annual temperature greater than 19°C. It occurs on a wide range of soil regimes in these regions. In China the jatropha usually blossoms and bears fruits only once a year, but there are also instances of two or more flowerings per year. In some small but high yielding pilot areas, dry fruit output is reported to be 9,000–12,000 kg per ha, whereas in large plantings the output averages only about 1,800 kg per ha. In order to contribute to sustainable production of jatropha, further studies focused on different ecotypes, improvement of seed quality, plantation techniques, flowering and fruiting characteristics, and harvest and post-harvest handling of seeds are required. More research on biomedicinal potential of various parts of the plant and more information on the actual and potential markets is needed to realize the full potential of jatropha.     

生物能源树种麻疯树的研究进展及育种探讨

主要概述了生物能源树种麻疯树的资源分布、繁殖技术、栽植适应性评价及生理指标测定、生物技术、籽油的提取及品质分析等方面的研究进展,并对今后的遗传育种策略进行了探讨。     

Estimation of net gain of soil carbon in a nitrogen-fixing tree and crop intercropping system in sub-Saharan Africa: results from re-examining a study

Nitrogen (N)-fixing tree and crop intercropping systems can be a sustainable agricultural practice in sub-Saharan Africa and can also contribute to resolving climate change through enhancing soil carbon (C) sequestration. A study conducted by Makumba et al. (Agric Ecosyst Environ 118:237?C243, 2007) on the N-fixing tree gliricidia and maize intercropping system in southern Malawi provides a rare dataset of both sequestered soil C and C loss as soil carbon dioxide (CO₂) emissions. However, no soil C gain and loss estimates were made so the study failed to show the net gain of soil C. Also absent from this study was potential benefit or negative impact related to the other greenhouse gas, nitrous oxide (N₂O) and methane (CH₄) emissions from the intercropping system. Using the data provided in Makumba et al. (Agric Ecosyst Environ 118:237?C243, 2007) a C loss as soil CO₂ emissions (51.2?±?0.4?Mg?C?ha^?1) was estimated, amounting to 67.4% of the sequestered soil C (76?±?8.6?Mg?C?ha^?1 in 0?C2?m soil depth) for the first 7?years in the intercropping system. An annual net gain of soil C of 3.5?Mg?C?ha^?1?year^?1 was estimated from soil C sequestered and lost. Inclusion of the potential for N₂O mitigation [0.12?C1.97?kg?N₂O?CN?ha^?1?year^?1, 0.036?C0.59?Mg CO₂ equivalents (eq.) ha^?1?year^?1] within this intercropping system mitigation as CO₂ eq. basis was estimated to be 3.5?C4.1?Mg CO₂ eq.?ha^?1?year^?1. These results suggest that reducing N₂O emission can significantly increase the overall mitigation benefit from the intercropping system. However, significant uncertainties are associated with estimating the effect of intercropping on soil N₂O and CH₄ emissions. These results stress the importance of including consideration of quantifying soil CO₂, N₂O and CH₄ emissions when quantifying the C sequestration potential in intercropping system.     

麻疯树2年生人工林构筑型对修枝与土壤肥沃性的响应

本文首次采用固定枝级划分方法,试验研究了麻疯树构筑型对土壤肥沃性的响应,并探究了构型调控效果的资源反应。结果表明:1)土壤肥沃时麻疯树分枝率高、分枝角度小、枝长较长,构型为密集型;土壤瘠薄时麻疯树分枝率低、分枝角度大、枝长较短,构型为游击型;2)人为修枝也没有明显影响构型对土壤肥沃性的响应策略,但却显著增加了肥沃生境下构型的密集性(30→22°);3)人为修枝改变了贫瘠生境下一级枝长度、一级枝枝径与二级枝长度,具有壮枝作用,而对肥沃生境树体枝条大小影响不明显(二级枝枝径例外);4)据分析,同龄顶芽间距离为间隔子,分枝间夹角为分枝角度,分枝率是分枝强度,类似于克隆植物构型;5)构型枝级划分采用了固定枝序法确定,主干分枝为一级枝,一级枝分支为二级枝,增加了枝级的稳定性,与传统枝级划分方法相反;6)分析还发现,麻疯树构型对资源异质性的响应根源在于一级枝分枝角度,该参数塑造了游击性与密集性的构型特性。     

Molecular cloning and expression analysis of a gene encoding a putative beta-ketoacyl-acyl carrier protein (ACP) synthase III (KAS III) from Jatropha curcas

A cDNA clone encoding a putative beta-ketoacyl-acyl carrier protein (ACP) synthase III (KAS III) was isolated from Jatropha curcas L., a woody oil plant. The cDNA clone (named JcKAS III) contained a 1203-bp open reading frame coding for 400 amino acids with a predicted molecular mass of about 42 kDa. The deduced amino acid sequence of the cDNA clone shares about 80% identity to KAS III from other plants, and contains a conserved Cys(176) in the active site and the amino acid motif G(355)NTSAAS(361) which is responsible for binding regulatory acyl-ACPs. Southern blotting analysis indicated that JcKAS III is a single copy gene in the J. curcas genome. Quantitative real-time PCR analysis showed that JcKAS III was expressed in all tissues examined with highest expression in roots, and that expression of JcKAS III increased as seeds developed.     

云南及周边地区麻疯树种子的油脂评价及利用

2008年8~11月对云南及周边麻疯树种质资源调查并收集200余份种子,进行了种子和种仁含油量评价;通过选取代表样地,即云南双柏南布河边及昆明东川区炭窑子,进行了工业出油率评价,发现种子工业出油率33.38%~44.90%;选取6个代表样地评价了种质资源的生物学性状、油脂的理化性质和脂肪酸成分分析,发现四川宁南种子千粒重713.90 g,6个样地平均种仁含油量60.52%,云南宾川种子的不饱和脂肪酸含量高达79.68%;云南育种工作者利用收集的种质资源,以高产、种壳薄脆、高含油量等为选育目标,其中选育出麻疯树高产品种2个、高含油量品种4个、高油酸品种1个。     

Establishing jujube trees in sub-Saharan Africa: response of introduced and local cultivars to rock phosphate and water supply in Burkina Faso, West Africa

In the Sahel zone, there is an increasing interest of farmers in conserving and enriching tree diversity on their farms as a source of food and income. Ziziphus mauritiana Lam. is one of the tree species farmers maintain on their farms. Even though the local variety of Ziziphus mauritiana Lam. was ranked as one of the most preferred species, it produces small fruit whereas farmers are interested in varieties producing bigger and tasty ones. A factorial experiment in a split split-plot design was carried out to assess the performance of three introduced cultivars of Indian jujube in Burkina Faso. Investigated factors were irrigation (irrigated with 30 l plant⁻¹ week⁻¹, non-irrigated), rock phosphate containing 25% P₂O₅ (0 and 150 g P plant⁻¹) and cultivar (Gola, Seb, Umran, and local variety as control). Eighteen months after planting, Umran responded positively to irrigation and rock phosphate treatments by displaying the tallest height (313 cm) and the biggest collar diameter (6.4 cm). Gola gave the largest crown diameter (316 cm) at 18 months and the highest fruit production at the first (15.3 kg tree⁻¹) and second (71.6 kg tree⁻¹) fruiting seasons in the irrigated and fertilized treatment. The local variety was less productive compared to the introduced cultivars. In terms of income generation irrigated and fertilized Gola and irrigated Umran showed the highest potential after two fruiting seasons with net revenues of F CFA 2,526,915 and F CFA 1,930,546 per hectare respectively. Therefore, Umran and Gola may be recommended in intensive sub-Saharan peri-urban systems while Seb needs further investigation to improve its water and nutrient use efficiency through either better timing of water and fertilizer application or symbiotic association with arbuscular mycorrhizal fungi.     

Simultaneous reduction in incidence of Bemisia tabaci (Hemiptera: Aleyrodidae) and Sylepta derogata (Lepidoptera: Pyralidae) using velvetleaf,Abutilon theophrasti as a trap crop

Journal of Pest Science - Trap cropping is a useful tool in sustainable pest management. Trap crops usually target a single species or genus of insect pests. In this study, we assessed the...     

Exploiting the potential of indigenous agroforestry trees: Parkia biglobosa and Vitellaria paradoxa in sub-Saharan Africa

Agroforestry Systems - Parkia biglobosa (néré) and Vitellaria paradoxa (karité) are indigenous tree species that are economically and socially important for local people in...     

Comparison of socio-economic and ecological benefits of bamboo and trees: the perspectives of local communities in south-western Ghana

Natural forests are disappearing in many tropical countries, resulting in loss of biodiversity and erosion of forest-dependent livelihoods. The maintenance and restoration of forests as well as a search for alternative natural resources that can concurrently improve the environment and enhance incomes of local communities has become crucial. Bamboo is suggested as a resource, which could substitute trees for socio-economic and ecological purposes in developing countries in the (sub)tropics. However, the relative importance of bamboos and trees for socio-economic and ecological purposes in bamboo-growing communities is not yet studied. Here, we present a study conducted to compare the socio-economic and ecological benefits of bamboo and trees from the perspectives of three bamboo-growing communities in the Wassa East District of Ghana. The compared benefits were ranked on a five-point Likert scale and significance of differences was tested at the 95% confidence level. For socio-economic benefits, trees were ranked significantly higher than bamboo for domestic energy, medicinal use and commercial harvesting; however, furniture, building and construction were not significantly different. For ecological benefits, bamboo was ranked significantly higher than trees for erosion control and riverbank protection. Trees, on the other hand, were ranked significantly higher than bamboo for biodiversity conservation, carbon sequestration and oxygen generation. The results imply that transforming bamboo into suitable products to meet communities’ energy needs could alleviate pressure on trees in natural forests.     

麻疯树新基因JcPIP的分子克隆与功能研究

从大戟科耐旱植物麻疯树cDNA中克隆得到了一个麻疯树质膜内膜蛋白(PIP)新基因(JcPIP).其cRNA在非洲爪蟾卵母细胞(Xenopus oocytes)中异源表达后发现细胞膨胀率扩大了10倍.聚类分析表明,麻疯树PIP蛋白与蓖麻、葡萄和菠菜PIP蛋白在进化上有最近的亲缘关系.半定量RT-PCR研究表明该基因在植株的整个生长发育期都有表达.但干旱胁迫下JcPIP基因表达量没有显著变化.     

贵州省建造石头梯田对限制水土流失的效益和风险分析

在贵州全境建造石头梯田来减少水土流失的现象十分普遍。但此项技术本身却有其固有的风险性。石头梯田通常比土质的梯田高,填在石头挡墙中的土壤的量更大,更易导致梯田的垮塌,也会减少梯田上部的土壤,降低土壤的养分和水分含量。石头的挡墙会威胁土地的长期生产力,因为一旦石头挡墙垮塌,所有的碎石就会堆积在下部的梯田中,使耕作十分困难。这种垮塌现象会通过增加地表径流而形成冲沟,使向下的沉积物运输增加。尤其是梯田之间的人工排水道使这种风险加剧。因为这种排水道使降水很难渗人土壤中,使土壤的保水和蓄水能力下降,从而造成作物的受旱。水流通过排水道输送的速度加快,很容易造成水流的汇集,增加洪水泛滥的可能性。由于建造了排水道,即使一般的暴雨,也会因为输送速度的加快而导致洪峰升高而成灾。因此,对水土流失的工程治理方式不应该取代、而应该与好的土地管理策略相结合。尽管土地利用方式有所改变,但通过采用新技术和坚持可持续发展的原则,在此类的土地上仍可获得最高的产量。图7表1参14。     

Ethylenediurea(EDU) effects on Japanese larch: an one growing season experiment with simulated regenerating communities and a four growing season application to individual saplings

J apanese larch(La rix kaempferi(Lamb.) Carr.)and its hybrid are economically important coniferous trees widely grown in the Northern Hemisphere.Ground-level ozone(O_3) concentrations have increased since the preindustrial era,and research projects showed that Japanese larch is susceptible to elevated O_3 exposures.Therefore,methodologies are needed to(1) protect Japanese larch against O_3 damage and(2) conduct biomonitoring of O_3 in Japanese larch forests and,thus,monitor O_3 risks to Japanese larch.For the first time,this study evaluates whether the synthetic chemical ethylenediurea(EDU) can protect Japanese larch against O_3 damage,in two independent experiments.In the first experiment,seedling communities,simulating natural regeneration,were treated with EDU(0,100,200,and 400 mg L~(-1)) and exposed to either ambient or elevated O_3 in a growing season.In the second experiment,individually-grown saplings were treated with EDU(0,200 and 400 mg L~(-1)) and exposed to ambient O_3 in two growing seasons and to elevated O_3 in the succeeding two growing seasons.The two experiments revealed that EDU concentrations of 200-400 mg L~(-1) could protect Japanese larch seedling communities and individual saplings against O_3-induced inhibition of growth and productivity.However,EDU concentrations ≤200 mg L~(-1) did offer only partial protection when seedling communities were coping with higher level of O_3-induced stress,and only 400 mg EDU L~(-1) fully protected communities under higher stress.Therefore,we conclude that among the concentrations tested the concentration offering maximum protection to Japanese larch plants under high competition and O_3-induced stress is that of 400 mg EDU L~(-1).The results of this study can provide a valuable resource of information for applied forestry in an O_3-polluted world.     

The genetic diversity of Jatropha Curcas (L.) germplasm in Ghana as revealed by random amplified polymorphic DNA (RAPD) primers

Jatropha curcas (L.) has gained popularity as a biodiesel plant to serve as an alternative fuel source and generate income to small landholders. The success of J. curcas as alternative fuel source and income generation depends on the identification of genetically divergent materials of the plant and developing superior planting stocks for farmers. This paper presents genetic diversity assessment of 40 representative accessions drawn from 90 accessions collected from ten regions of Ghana based on their seed yield performance. Random Amplified Polymorphic DNA (RAPD) analysis on the 40 accessions with ten primers revealed an average polymorphism of 24.99%. Genotype Genotype*Environmental biplot analysis which incorporates divergence effects due to genotype (PC1) and interactions between genotype and field parameters (PC2) was 44.7%. Hence the RAPD information indicates narrow genetic diversity among the accessions used in the study and J. curcas germplasm in Ghana. It is therefore recommended that local germplasm of J. curcas should be officially conserved and immediate efforts be made to widen the genetic base through research and introduction from other regions.     

Invasive alien trees and water resources in South Africa: case studies of the costs and benefits of management

Invasive alien plants are consumptive water-users, and may have reduced river flows in South Africa by about 6.7% according to a broad-scale study. An effective programme to bring the invasions under control would cost about US$ 92 million per year for the next 20 years. This paper reports on studies of four representative catchments (the Sonderend, Keurbooms, Upper Wilge and Sabie-Sand) to assess the impacts and costs of invasions at a scale that is more relevant to managers. Several alien plant species have invaded the catchments. Non-riverine invasions are mainly Pinus and Hakea species in Sonderend and Keurbooms, eucalypts in the Upper Wilge, and pines and scramblers (e.g. Lantana camara) in the Sabie-Sand catchment. Riverine invasions are dominated by Acacia mearnsii and, to a lesser extent, A. dealbata, except in the Sabie-Sand and the lower Sonderend River where Eucalyptus species are important. About 44% of the Sonderend, 54% of the Keurbooms, 2% of the Upper Wilge and 23% of the Sabie-Sand catchments has been invaded to some degree. The corresponding reductions in the natural river flows attributed to these invasions are about 7.2, 22.1, 6.0 and 9.4%. If the invasions are not controlled they could potentially spread, and occupy 51, 77, 70%, respectively, of the first three catchments. At an annual expansion rate of 10–15% this would take about 13, 26 and 63 years, respectively. The invadable areas in the Sabie-Sand catchment are already invaded so invasions will only increase in density. It would take about 26–30 years to reach 100% canopy cover. The projected flow reductions for the four catchments would increase to 41.5, 95.5, 25.1 and 22.3%, respectively. The estimated cost of the control programmes to prevent these losses would be about US$ 13.2, 9.9, 4.1 and 6.6 million for the Sonderend, Keurbooms, Upper Wilge and Sabie-Sand catchments, respectively. Should the catchments be allowed to become fully invaded before control operations were started, then the costs would rise to US$ 86.5, 20.5, 278.0 and 11.1 million, respectively. The impacts and costs are significant and are comparable with those calculated independently for other South African catchments. Water is acknowledged to be a key constraint to economic growth in South Africa and there is considerable pressure for efficient and sustainable use of the limited water resources. The projected impacts would justify control programmes aimed at clearing alien invaders for water conservation.     

Osmotic potential of spruce,fir and beech as a contribution to water budget in connection with forest decline (“Waldsterben”)

Osmotic cell sap potentials of diseased and healthy spruce, fir and beech leaves, fine roots and cortes were determined with the aid of capillary cryoscopy. With one exception (fir needles) the diseased trees showed no reduction in osmotic potential compared to healthy trees.