Jatropha curcas L.

International Journal of Agronomy and Plant Production. Vol., 4 (S), 3804-3815, 2013 Available online at http:// www.ijappjournal.com ISSN 2051-1914 ©2013 VictorQuest Publications

Production Approaches to Establish Effective Cultivation Methods for Jatropha (Jatropha curcas L.) under Cold and Semi-arid Climate Conditions 1,2

3

3

3

Sayuri Inafuku-Teramoto , Charles Mazereku , Tidimalo Coetzee , Chiyapo Gwafila , Lekgari A. 3 3 1 1 3 Lekgari , Dikungwa Ketumile , Yasunori Fukuzawa , Shin Yabuta , Masego Masukujane , Derick 3 3 1 1 4 G.M. George , Stephen M. Chite , Masami Ueno , Yoshinobu Kawamitsu , Kinya Akashi 1-Faculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami-gun, Okinawa 903-0213, Japan 2-JICA JOCV Botswana Office, Private Bag 00369, Gaborone Botswana 3- Department of Agricultural Research, Ministry of Agriculture, Private Bag 0033, Gaborone, Botswana 4- Faculty of Agriculture, Tottori University, 4-101 Koyama-cho, Tottori City, 680-8550 Japan * Corresponding author: Sayuri Inafuku-Teramoto Abstract Consistently high yield production of Jatropha has not yet been achieved in Africa. Spurred by the international focus on Jatropha as a non-edible biofuel, Jatropha production trials began in Botswana in 2012. Exploration of genetic resources throughout Botswana yielded 97 accessions, with selection still ongoing. Most Jatropha trees in Botswana are concentrated in northern regions, where they are grown as ornamentals and have apparently been introduced from outside the country. The purpose of this study was to establish an economical cultivation method for Jatropha under marginal dry and cold climate conditions. To enhance winter survival in 2012, pruning, followed by covering with non-woven polyester sheets, was used. These practices significantly decreased plant mortality and accelerated new shoot growth in spring. Based on weather data, Jatropha trees were exposed to cold stress caused by several hours of pre-cooling and subsequent freezing temperatures from strong radiational cooling in the morning. Below-freezing winter temperatures were recorded in the field, especially before dawn. A high diurnal temperature range and low dew point intensified radiational cooling, with water-rich Jatropha stem tissues and sprouting leaves damaged by freezing and rapid thawing. Repeated freeze damage also delayed sprouting in spring. Our trial cultivation results suggest practices for overcoming dry and cold conditions, and support the possibility of Jatropha production in African desert climates. Keywords: Biodiesel crop, Genetic resources, Cold injury, Marginal climate conditions, High diurnal temperature range, Radiational cooling Introduction Jatropha (Jatropha curcas L.), a member of the family Euphorbiaceae and a native of Central America, is one of several important oil crops that can be grown in subtropical and tropical climates. Economic yield starts after 3 years, with trees continuing to produce seed for 50 years (Kumar and Sharma, 2005). Reported seed yield (Kaushik et al., 2007, Srivastava et al., 2011, Wani et al., 2012) varies widely (0.4–12 t ha−1 yr−1) and is strongly related to growth environment (Openshaw, 20 00; Kumar and Sharma, 2005; Jongschaap et al., 2007; Achten et al., 2008; Behera et al., 2010; Srivastava et al., 2011). Depending on extraction method (Kumar and Sharma, 2005; Reinhardt et al., 2008; Wani et al., 2009; Barua, 2011), Jatropha seed oil yields as high as 25–30% of seed weight can be obtained. Other

Intl. J. Agron. Plant. Prod. Vol., 4 (S), 3804-3815, 2013

portions of the plant as well as byproducts from biofuel production have also been utilized as biomass (Openshaw, 2000; Kumar and Sharma, 2005; Jongschaap et al., 2007; Achten et al., 2008; Kumar and Sharma, 2008). Because of global CO2 emission trends and food security concerns, non-food oils, such as those derived from Jatropha, are preferred over edible oils for biofuel use. In addition, cultivation of such crops on waste lands not suitable for food production has been a focus in developing countries (Sreedevi et al., 2009; Brittaine and Lutaladio, 2010). Genetic and environmental factors have a significant impact on Jatropha oil yield production, with environment observed to be more important than genetics in some cases (Jongschaap et al., 2007; Achten et al., 2008; Rao et al., 2008). Optimum growing conditions are found in areas of 1000–1500 mm annual rainfall and temperatures of 20–28 °C with no frost (Kumar and Sharma, 2005; Achten et al., 2008; Divakara et al., 2009; Brittaine and Lutaladio, 2010; Garg et al., 2011). Jatropha curcas cannot tolerate frost or temperatures below 0º C (Britaine and Lutaladio, 2010) but can also survive in marginal semi-arid climates with poor fertility (Openshaw, 2000; Jongschaap et al., 2007; Acten et al., 2008; Garg et al., 2010; Sirvastava et al., 2011). In spite of the Botswana’s harsh climate condition, there are ornamental cultivations of Jatropha crucas and several related species (Setshogo, 2005) found in wild. However, the cultivation is a challenge in research or commercial farms, requiring reliable methods and techniques to assure survival. In response to the increasing energy demands, our co-research project was initiated to expand the diversity of available energy sources in Botswana. In particular, we are aiming to identify best agronomic practices and develop high oil-yielding Jatropha cultivars suitable for the cold and dry climate condition. Another goal of our ongoing study is to identify different ways to utilize non-oil biomass products of Jatropha. Unfortunately, limited information exists regarding Jatropha cultivation in Africa, especially in marginal climates (Rajaona et al., 2011; Srivastava et al., 2011; Wicke et al., 2011). In this paper, we report the results of the first stage of our project. The goal of this portion of the study was to clarify details of plant mortality in winter and to develop basic breeding and cultivation approaches to overcome the dry and cold marginal climate of southern Africa. Materials and Methods Exploration, collection, and selection of Botswanan Jatropha accessions Jatropha germplasm (seeds) was collected from five districts in Botswana (Kweneng, Ngamiland, Southeast, Northeast, and Central). A total of 85 accessions were collected in 2011, with another 12 obtained in 2012. Observations and propagation were conducted during and after explorations. GPS data were recorded for each Jatropha plant, and tree circumference was measured using a tape ruler. Leaves, fruit and seed numbers, and related morphological parameters were determined and recorded. Size and weight of harvested fruits and seeds were measured using a digital slide caliper and laboratory scale, respectively. Field location and climate summary A Jatropha experimental field was established at the Department of Agricultural Research station located in Botswana’s capital city, Gaborone. This field is in the northern part of the city, at an altitude of 992 m, latitude of 24.33.40 S, and longitude of 25.56.37 E. Field soils are classified as coarse textured clay loam with fairly large amounts of dry matter. The field slope is less than 10°. Prior to establishment, the land had been left fallow for two years, with its vegetation mainly used as forage for livestock. The field is wide and flat, and is sparsely surrounded by shrubs and trees. The climate of the research station is semi-arid, with annual rainfall ranging from 230–500 mm. Based on the revised Köppen-Geiger climate classification, most of Botswana possesses an aridsemiarid steppe climate (Peel et al., 2007). Temperatures range from a minimum of −5 °C in winter to a maximum of over 40 °C in summer, with night-day temperature fluctuations common. Humidity is usually low during the day, especially in the dry winter season. The maximum diurnal temperature may vary by as much as 28 °C in the dry winter season, with a lower range observed in summer. The dry winter season runs from May to August, and summer extends from October until February. Climate and soil analysis Climatic data were obtained using a Pessl iMETOS ag iMETOS 1 type weather station (Pessl Instruments, Weiz, Austria). The weather station, established at the farm in 2009, monitored air temperature (1.5 m height), precipitation, air humidity, solar radiation, wind direction and speed, dew point, and leaf wetness. This weather station started to record the hourly average data from 1 August

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2009. Data collected daily over three winters were used to derive a maximum temperature simulation formula following the method of Asakura et al., 2011. Field sensors (RTC-21; Espec Mic, Aichi, Japan) were placed in the middle of the Jatropha experimental field; three sensors were used to monitor air temperature and air humidity (+30 cm), and two recorded ground temperature (−15 cm). Soil minerals were analyzed by ICP-MS (ICPS-8100; Shimadzu, Kyoto, Japan) at the University of the Ryukyus. Covering, pruning, and watering treatments The experimental field was plowed with a moldboard plow to soften the soil and incorporate existing vegetation. Planting holes, 0.70 m deep and spaced 2 m x 2 m apart, were made in preparation for planting tree seedlings. The 85 accessions were germinated on seed trays in net houses before transplanting. Seeding on trays was carried out in July 2011. Two weeks after emergence, seedlings were transplanted into larger polythene pots and kept under net shading for 3 months. In December 2011, the 85 accessions (748 plants) were transplanted into the field. Each plot consisted of 10 plants per accession; however, because some accessions had low germination/emergence rates (about 30%), some plots contained fewer than 10 plants. Three trees were planted on the outer side of the field to act as guard rows. Trees were manually irrigated weekly for seedling establishment. Before the beginning of winter, trees were pruned to 20 cm high using secateurs. Pruning was not carried out on the border rows. Of the pruned trees, 50% were covered with a frost cover material (100% polyester non-woven fabric) as additional protection from frost damage. At the beginning of spring, on 24 August 2011, the covers were removed. A drip irrigation system was installed in July 2013, and weekly irrigation was carried out at a rate of 5 L per plant. Because of uneven sprouting of new leaves and the growth rate observed in October, data related to mortality from cold injury were collected in September 2012 and January 2013. New sprouting shoot numbers and longest sizes were determined, and growth rate was measured based on five different leaf sprouting levels. To compare covered and non-covered plants, all data were statistically analyzed using Student’s t-test. Results and Discussion Exploration, collection, and selection of Botswanan genetic resources Based on the results of 2011 and 2012 explorations, six superior Jatropha trees from northern Botswana were selected. Their morphological and reproductive characteristics are summarized in Table 1. All examined Jatropha locations are indicated in Fig.1.

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Fig 1. Map of Botswana showing locations of Jatropha genetic resources collected in 2011 – 2012.

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Table 1. Morphological characteristics of superior Jatropha collected in northern Botswana. No.

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Location

Age Diamete Height (year) r (cm) (m)

121206-1 Mokubilo

7

120

3

121206-2 Sebina

10-12

127

3.5

121206-5 Tsamaya

12

62

3

121207-1 Jackals1

7

67

2.5

121207-2 Tonota

15

153

3.5

121207-3 Palapye

12

90

3

Leaf robes

Leaf size Filled seeds (%) (mm)

3 sharp 110 x 120 2 round 1 sharp 90 x 90 4 round 5 sharp 120 x 120 1-3 sharp 130 x 130 2-4 round 100-110 3-5 sharp x 1000-2 round 110 1-3 sharp 110 x 2-4 round 110-130

100-seeds weight (g)

Numbers of fruits Comments set

86.67 ± 4.71

65.51 ± 4.77

6.42 ± 1.98

90.00 ± 2.89

64.34 ± 2.05

6.33 ± 2.18

90.00 ± 4.08

70.52 ± 3.15

10.46 ± 3.10

89.05 ± 3.17

74.43 ± 4.88

8.00 ± 2.92

86.67 ± 2.72

72.24 ± 5.00

4.23 ± 2.24

78.33 ± 7.35

78.67 ± 2.62

3.92 ± 1.50

Sprouting

high percentage of 2-seeds fruits, empty seeds


Most Jatropha trees, subject to climate conditions, grow well in northern Botswana. The majority of these trees are young plants grown in yards next to houses and other building structures because of human activity. In these locations, they are not severely affected by cold damage, as heat insulation effects from brick walls, coupled with the presence of other hedge trees and ordinary morning activities, can prevent radiational cooling. As implied by its absence in the wild and its use as an ornamental in large northern cities such as Maun and Francistown, Jatropha is an introduced plant. Based on ages and locations, almost all Jatropha trees in Botswana appear to be introduced from Zimbabwe. Like Jatropha genetic resources in Asia (Ginwal et al., 2005; Kaushik et al., 2007; Divakara et al., 2009; Srivastava et al., 2011; Wani et al., 2012), the Botswanan accessions exhibit morphological variation. A molecular analysis is currently underway to evaluate their genetic diversity. Although a selection process has been established, acquisition of harvest data from the Botswanan accessions is necessary for further selection breeding. In addition to development of successful cultivation methods, effective propagation techniques must be generated, as young plants are normally far more strongly affected by environmental stress than mature trees (Ye et al., 2009). Field climate analysis and Jatropha growth Soil analysis data from the Jatropha production field are shown in Table 2. The brick-colored clayeysandy soil, although of poor fertility, was rich in Al, Fe, and Na, with a neutral pH value. These data indicate the soil is adequate for growing Jatropha under appropriate climate conditions (Behera et al., 2010). Table 2. Data from soil analysis of the Gaborone (Sebele) experimental field.

Mineral Si Al Fe K Ca Na Mg S Mn P B Zn Cu Mo

(mg/100g soil) Average S.D. 79.716 ±26.32 18.701 ±7.06 9.863 ±3.47 5.928 ±2.47 2.381 ±2.71 2.202 ±0.47 1.159 ±0.38 0.473 ±0.15 0.119 ±0.05 0.059 ±0.02 0.058 ±0.01 0.028 ±0.02 0.004 ±0.00 0.003 ±0.00

The most important requirement for successful Jatropha production in Botswana is a means of overcoming the dry, cold winter season. During the winters of 2009–2011, the Jatropha experimental field actually failed to maintain Jatropha trees. To better understand the Botswana-specific climate, we collected climatic data for Sebele, the area of Gaborone in which the Jatropha field is located. This data, summarized in Table 3 and Fig. 2, revealed a lack of water resources and a temperature range not conducive to Jatropha growth. For example, Jatropha normally needs 1000–1500 mm of annual precipitation, but only 332.6 mm of precipitation occurred in 2012. Appropriate irrigation will be necessary for commercial Jatropha production in Botswana. The rainy season takes place during Jatropha’s growth period, with the rains normally occurring in thunderstorms. The high daytime temperatures and solar radiation suggest the difficulties of maintaining adequate soil moisture levels throughout the year (data not shown). In addition, high flux density and low daytime humidity readily lead to high rates of evaporation from both plant and soil surfaces (Liang et al., 2007). This marginal climate is one of the reasons for the lower growth rates observed for Jatropha trees in Botswana compared with those planted in tropical Asian countries (Srivastava et al., 2011; Wani et al., 2011) In winter, there is a high diurnal temperature range, with minimum temperatures easily dropping below freezing because of radiational cooling under dry air conditions.

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Fig. 2. Monthly variation in field climate in Gaborone (Sebele, 2012). Table 3. Monthly variation in the climate of Gaborone (Sebele).

Season

Min. Months temp range (°

Max temp range(°

Diurnal range(° C)

Average

Precipitatio Precipitation* n* (mm) * (mm)

Spring

Sep Oct

10 - 15

29 - 32

17 - 19

25.6

59

Summer

Nov Feb

15 - 20

30 - 40

12 - 17

269.8

321

Autumn

Mar Apr

10 - 15

28 - 32

16 - 19

37.2

102

Winter

May Aug

-2 -+7

20 - 30

20 - 28

0.0

17

* 2012 ** http://www.climatedata.eu/climate.php?loc=bcxx0001&lang=en

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(°C) 45 40

Average Temperature (Winter)

35

Average Temperature (Summer)

30 25 20 15 10 5 0 1

2

3

4

5

6

7

8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 hour

Fig 3. Temperature variation in summer and winter in Gaborone (Sebele). Based on temperature data obtained from the iMETOS weather station, early morning below-freezing temperatures were the cause of cold injury. Data collected on typical winter days showed a higher diurnal temperature range than those in summer (Fig. 3). Given the presence of various contributory factors— dryness, high altitude, high diurnal temperature range, the wide flat space lacking buildings, and the absence of large water surfaces and nighttime wind, the weather data unsurprisingly revealed the daily occurrence of strong radiational cooling, especially in winter. Cold injury consequently took place several times in winter when air temperatures dropped due to invasion of a cold air mass from the south. The occurrence of strong radiational cooling was also reflected in differences in temperature at different setting heights: an inverted air layer was produced by radiational cooling, with the lowest temperatures recorded near the ground and on lower plant surfaces. For example, the field temperature sensor that recorded air temperature at 30 cm usually registered lower temperatures than did the iMETOS weather station located at 1.5 m (Table 4). Cold damage to Jatropha trees normally occurred after midnight, when temperatures dropped below freezing after several hours of pre-cooling. Because the dew point in the early morning was lower than the minimum temperature, the observed tissue damage must have been due to freezing caused by the continuous low temperature rather than frost. Jatropha unfortunately has moisture-rich stems, similar to baobab and other trees (Maes et al., 2006); when the temperature increased rapidly after dawn, the frozen cortex cells experienced quick thawing. This process is the main reason why non-pruned Jatropha trees were unable to survive in the field over several years. Table 4. Field temperature data from thermometers placed at different heights. (ºC)

Date 12-Jun-12 13-Jun-12 25-Jun-12 17-Jul-12 18-Jul-12 19-Jul-12 20-Jul-12 21-Jul-12 2-Aug-12

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Espec iMETOS (30cm) (1.5m) -5.00 -3.70 -2.50 -3.10 -3.10 -3.30 -2.70 -4.00 -2.80

-1.95 -0.98 0.17 0.19 0.01 -0.85 0.01 -0.76 0.07


From these results, a simulation formula for forecasting minimum temperature was derived from the iMETOS data using a modified method based on Asakura et al., 2011: Tm = Td − 8.7368•Ln(RH) + 33.378, Where Tm is the estimated minimum temperature, and Td and RH are dew point and relative humidity, respectively, at 19:00 on the previous day. Using this formula, the minimum morning temperature can be calculated from dew point and relative humidity data recorded 7 h previously, enabling prediction of minimum temperature when a cold air mass is coming from South Africa. Midnight temperature and low dew point are also good indicators for forecasting cold injury. Common methods used in temperate climate countries for frost protection, such as covering, heating, promoting air circulation, and watering, should also be useful for overcoming freeze injury during Botswanan winters. Physiological analysis of Jatropha in response to cold stress is also needed to develop proper Jatropha cultivation methods in Botswana. Pruning and covering effects against cold injury Only a few reports of Jatropha cultivation in Africa (Ginwal et al., 2005; Chapotin et al., Ye et al., 2009; 2006, Gwamuri et al., 2012) have appeared. Following our unsuccessful attempts to cultivate Jatropha in Gaborone in 2009, we applied pruning treatments to the Botswanan accessions transplanted in December 2011. Pruning is commonly used in Asia to boost yields and ease harvesting of Jatropha (Behera et al., 2010; Rajaona et al., 2011). In our trials, however, pruning was used to enhance survival after freeze injury. This approach—reducing Jatropha tree height and leaves to decrease freeze damage—seemed to work in 2012. Pruning was supposed to increase Jatropha tree survival rates during the winter of 2012, although most above-ground plant parts died due to freeze injury. Jatropha trees on the borders, which were nonpruned, experienced mortality rates twice as high as pruned trees. This result suggests that cold stress on remaining green leaves and young liquid-rich stem tops facilitated the heavy damage to Jatropha trees, and that young Jatropha plants are more strongly affected by environmental stress than are mature plants (Kumar and Sharma, 2005; Ye et al., 2009; Hayashi, 2012). New shoots emerged only from the base of pruned and non-pruned Jatropha trees, suggesting that tissue survived only on the lower parts of the plants. The pruning treatment had some protective effect, however, as it reduced freeze injuries. According to the weather data, the first attack of cold was on 10 June 2012; while the remaining leaves of border Jatropha trees immediately turned black and fell off (Fig 4), pruned and non-pruned Jatropha trees sprouted new leaves after this first freeze. A total of 9 days of belowzero temperatures were recorded in 2012, and Jatropha trees stopped sprouting new shoots after several cold attacks in August. Because winter temperatures in 2012 were less severe than in 2011 (data not shown), almost all Jatropha trees were able to survive in 2012. The effect of covering was evident on plants that survived the winter season. Covered Jatropha plants experienced earlier sprouting and displayed better growth than non-covered ones (Table 5). Data collected for both characteristics illustrate the positive effects of covering with non-woven polyester fabric as protection against cold attacks. Although new leaves and stems began sprouting in mid-September 2012, they sprouted unevenly, with new shoots appearing from September through December. Table 5. Comparison between growth of covered and non-covered Jatropha plants in Gaborone.

Measured parameter Covered Non covered P* Mortality rate (%) 1.50% 2.99%