EFTA01223096.pdf

M. Rural et at: A Confrolled Environmem Agriculture Greenluntsefor the Caribbean Region 10 ISSN 0511-5728 The West Indian Journal of Engineering Vol.40. No.2. January/February 20I8. pp.10-16 A Controlled Environment Agriculture Greenhouse for the Caribbean Region Maria Suraj Edwin I. Ekwue "•'", and Robert A. Birch' Department of Mechanical and Manufacturing Engineering. Faculty of Engineering. The University of the West Indies. St. Augustine. Tr' dies: "E-mail: 'E-mail: Corresponding Author (Received 28 June 2017; Revised 24 November 2017; 05 December 2017) Abstract: A prototype Controlled Environment Agriculture (CEA) greenhouse, designed to suit the climatic conditions of Trinidad and Tobago was constructed and tested alongside a non-controlled prototype greenhouse with natural ventilation. In the CEA greenhouse, fan and pad type evaporative cooling were used to reduce temperature; circulating air combined with natural ventilation to reduce the humidity and provide air movement. LED lights were used to extend day length and supplement photons delivered to the plants. The effect of these control measures, in the CEA greenhouse, was evaluated by measuring temperature and humidity variations. Plant growth parameters (plant height, stem diameter, and leaf surface area) were evaluatedfor the two greenhouses. The mean saturation effectiveness of the coconut fibre cooling pad material used in the evaporative cooler was found to be 25.3%. While, the temperature and relative humidity in the non-controlled greenhouse were higher; those in the CEA greenhouse were lower than the ambient temperature. The CEA greenhouse had significantly higher growth rates in all plant growth parameters (about two and a half times on the average) than the non- controlled greenhouse. The combination of blue LED light, evaporative cooling, and air circulation fans coupled with natural ventilation resulted in a significant increase in plant growth rates in the CEA greenhouse compared to the greenhouse with only natural ventilation as the weather control measure. Keywords: Greenhouse, controlled, environment, Trinidad and Tobago 1. Introduction and technical support to persons interested in greenhouse Trinidad and Tobago's food import bill is currently crop production. Sahadeo et al. (2017) investigated the approximately USS 0.6 billion per annum (Flemming et existing greenhouses, locally, regionally and al., 2015). There is an urgent need to increase food internationally and designed and optimised a new system production and reduce this expenditure. Protected that could potentially be used in the Caribbean region. agriculture has been proposed as one way to improve They found that while most designs could protect the agricultural output, by protecting the crops from harsh crops from pests and diseases, temperature and humidity weather conditions and pests and diseases (DeGannes et could be reduced only marginally by altering their al., 2014). If well implemented and followed through designs, and changing some materials. They, however, intelligently, protected agriculture environment systems found that to control the environmental parameters will aid in ensuring food security. According to Jensen adequately, Controlled Environment Agriculture (CEA) and Malter (1995), protected agriculture (PA) is "the greenhouses may be needed in the Caribbean. CEA is a modification of the natural environment to achieve subset of protected agriculture in which case all aspects optimum plant growth." In general, greenhouses are of the natural environment are modified for maximum environments which can be controlled to a much higher plant growth and economic return (Jensen and Malter, degree than outdoor fields. Greenhouses involve both 1995; Albright and Langhans, 1996). Control may be passive and active ways of controlling the growing imposed on air, temperature, light, water, humidity, conditions inside the green house. Temperature, light, carbon dioxide, plant nutrients alongside with complete air humidity, water supply and carbon dioxide in the air climatic protection (Jenson and Malter, 1995). Tian et can be regulated by the grower. In some modem al. (2014) did a comprehensive assessment of a greenhouses, even infestation by pests and pathogens can controlled growth environment in which they analysed be restricted or prevented (EGTOP, 2013). the effect of environmental factors, like temperature, Martin et al. (2008) reported the rejuvenation in the humidity, light, carbon dioxide and nutrients, on crop use of greenhouses in Trinidad and Tobago following a development. Their results showed that rapes grew very collaborative approach by Agricultural Development well; the growth period was short with higher quality Bank (ADB) and others to provide financial, marketing yields than rapes grown in natural environment. EFTA01223096 M. StaMer at: A Confrolled &yammers; Agriculture Greenluntsefor the Caribbean Region I The major disadvantage of the CEA greenhouses is incandescent bulbs, fluorescent bulbs, high intensity that they are very costly and may not be affordable to bulbs or light-emitting diodes (LED) lights. most local farmers. Before heavy investments are made, In a CEA greenhouse, an integrated computer it is, therefore, necessary to construct a prototype CEA system is used to ensure that ventilation, humidity, light greenhouse and compare its performance locally (in intensity, carbon dioxide levels and all other parameters terms of controlling temperature, humidity and other operate in harmony with one another so as to provide the environmental factors) to a greenhouse with minimal best growing conditions (Albright and Langhans, 1996). means of weather control. Such an investigation will While simple on-off switches may be used, a reveal whether the CEA greenhouses could lead to better computerised system offers remote monitoring and crop yields and control of weather conditions. This controls based on specific plant requirements (Karlsson, paper starts the investigation of CEA greenhouses in 2014; Goldammer, 2017). Sensors are placed in Trinidad by first designing and constructing a prototype greenhouses to acquire data. For sensors to be effective, CEA greenhouse and testing its performance against a they must be kept at plant canopy height with limited similarly constructed naturally ventilated greenhouse. direct influence from vents, fans or drafts (Karlsson, This research will predict the feasibility of large-scale 2014). use of CEA greenhouses in Trinidad and Tobago and in In computerised systems, sensors send data through the Caribbean. a data acquisition (DAQ) device for signal conditioning or through an analogue-to-digital converter (ADC) to 2. Existing Methods for Modifying the Environment computer software to analyse and process this data, to in CEA Greenhouses activate some type of control. Information from the De Gannes et al. (2014) identified the following computer software is used to activate the actuators using problems with CEA greenhouses in the Caribbean: high digital-to-analogue convertors. Thermostats or temperatures, high relative humidity, high carbon controllers are also utilised in CEA greenhouses. While dioxide concentration, low oxygen, reduced light thermostats control temperature, controllers continuously especially below minimum threshold level during monitor the greenhouse environment (Karlsson, 2014). rainy/cloudy days. Cheap and non-complex on/off systems (Goldammer, Karlsson (2014) reviewed the various methods of 2017) allow sensors to be directly connected to controlling environment in greenhouses (see Figure 1). environmental controllers that use relay controls to For instance, temperature is controlled by using natural switch on and off of pumps and fans. This is one way of ventilation, exhaust fans, evaporative cooling, mist reducing the cost of CIA greenhouses and was adopted cooling and shade curtains. Relative humidity is in this study. modified by using circulating fans, exhaust fans, natural ventilation and dehumidifiers. Supplemental lighting is 3. Design and Construction of Prototype provided using incandescent light bulbs, halogen Greenhouses Two prototype greenhouses were constructed and placed alongside each other (see Figure 2). Both greenhouses was NAYS Eased teal E•mxtean Mit Coolies utilise the Quonset structure which has been altered to Tea•Grann Viniates a. <Mica improve natural ventilation, by means of a butterfly vent. Ut De Gannes et al. (2014) recommended the Quonset model of greenhouse with a split-roof as the best for the Caribbean region. Sahadeo et al. (2017) modelled and Rain c.c.s., _rase. tested this model and verified this recommendation. _ Heft Mae Mr IR & Greenhouse A is a CEA greenhouse, while Greenhouse B is also a protected agriculture structure but with natural ventilation as the only means for controlling Al C•IINSINV VneYie environment. The latter greenhouse was constructed so Moven HA! Dna that both greenhouses could be tested side to side to see ir E if there are advantages of the CEA greenhouse. Each greenhouse is 2 m length, 1.5 m width and 2 m depth. The framework of the greenhouses was constructed with Septtenntil Deist 12.5 mm and 25 mm.diameter polyvinyl chloride (PVC) Lem.. • pipes. PVC cement was used to stick all the pipes into kr00o „MAU , ** • • their fittings. The greenhouse frame was covered with a It 0.15 mm thick, ultra violet (UV) resistant, low density, clear polyethylene glazing material with a light transmittance of 80% to 90%. The main structure and Figure I. Methods of controlling greenhouse environment glazing of protected greenhouses have been fully 11 EFTA01223097 M. Ramjet at: A Conrrolled Environmem Agriculture Greenhousefor the Caribbean Region 12 described by Sahadeo et al. (2017). Figure 3 shows the environment. The efficiency of evaporative coolers was diagram of the CEA greenhouse (Greenhouse A). tested in Trinidad by Deoraj et al. (2015) with some limited success. The CEA greenhouse therefore utilised in addition, natural ventilation so as to ensure that even without any of the automated systems being engaged, air was constantly exchanged between the external and internal environment, so that the crops got a fresh intake of air regularly. As the hot air expands and rises, it escapes the greenhouse through the butterfly vent. When the internal temperature of the greenhouses exceeds maximum threshold of about 35°C (monitored by a temperature lobs controller), the evaporative cooling system will be activated, the exhaust fans and pump will switch on and a phij_ the evaporative cooling process will start. When the temperature drops to the optimum level, the system will la) Greathouse A: With contolkd (b) GICelli10.1% B With so conunlled CRY 1/011IKit nat011131CIII disengage. When the humidity inside the greenhouse exceeds 70% (monitored by a humidity controller), the Figure 2. The two constructed prototype green houses two circulating fans (each 100 mm diameter), will switch on. When the humidity drops below 70%, the circulating fans will switch off. However, if the exhaust fans of the evaporative cooling system are on, the circulating fans will not switch on and vice versa. This is to avoid turbulence and vortices from developing due to the simultaneous circulation of air and the air being pulled through the greenhouse by the extractor fans. Supplementary lighting was achieved using three light emitting diode (LED) fixtures. LED grow lights (Figure 3) have several advantages over traditional light sources: They are energy efficient, cheap to maintain and are long-lasting (Karlsson, 2014). The LED lights encourage photosynthesis and crop growth (Tian et al., 2014; Suraj, 2017). 4. Testing of the Constructed Prototype Greenhouses Figure 3. Controlled Environment Agriculture greenhouse (Greenhouse A) Two tests were carried out. The first test examined the efficacy of the coconut fibre as an evaporative pad on two operating parameters of evaporative cooler Temperature control was achieved using two (saturation efficiency of the evaporative pad and the extractor fans (each 30.5 cm diameter) and a pad temperature difference between the ambient conditions evaporative cooling system. The pad frame (1.6 m and the inside of the CEA greenhouse). The procedure width, 0.8 m height and 0.762 m thickness) was used by Deoraj et al. (2015) was used in this study. A constructed using pitch pine pieces. The pad material tank was filled with pipe-borne water (Tag = 28.6°C) and was shredded coconut fibres. Deoraj et al. (2015) found the pump was switched on. The airflow rate of the that coconut fibres are efficient for local use as pad extraction fans was measured with an anemometer. Wet material in evaporative coolers. For maximum efficiency and dry bulb thermometers were used to measure the wet and effectiveness, the greenhouse was designed to be air- and dry bulb air temperatures entering the evaporative tight, so that there was no disruption in or alternative pad and another dry bulb thermometer was used to path to airflow. Extractor fans drew the air from outside measure the temperature of the air entering the through the pad, since nature does not allow for a greenhouse. Temperatures were measured every 15 mins vacuum. The pad was continuously being wetted by a for 3 hours. The test was performed in the morning 0.01 hp pump (not shown in Figure 3) which supplies (9.00 a.m. to 12 noon) and it was repeated in the evening water to it from a tank. from 1 p.m. to 4 p.m. The saturation effectiveness of the As the air passed through the wet pad, it was cooled evaporative cooling pad was calculated using the by evaporation. Evaporative cooling, however, works Equation 1 (ASHRAE, 2007). best in less humid conditions, since the cool, moist air e— x 100 being drawn through the pad adds humidity to the t s— 9 12 EFTA01223098 M. Ramie: at: A Confrolled Environment Agriculture Greenhousefor the Caribbean Region 13 Where E is saturation efficiency (%), ti is dry bulb Saturation effectiveness and temperature difference, as temperature of entering air (K), t2 is dry bulb temperature expected, were higher in the evening than in the morning of leaving air (K) and t' is the wet bulb temperature of and this agrees with results by Dagtekin et al. (2009) as entering air (K). the weather conditions throughout the day affected the The second test involved the planting of some system. vegetable crops in both greenhouses to test the efficiency These values were much lower than the of the CEA greenhouse. Two plant troughs, each 120 cm corresponding average values of 53.5% and 3.6 °C found length and 60 cm width were filled with peat moss mix by Deoraj et al. (2015) for coconut fibres similar to the to a depth of 20 cm, and placed in the two greenhouses ones used in this test. They operated their fans at 4 m/s, (see Figure 2). The troughs had openings at the bottom 6 m/s and 8 m/s compared to average of 2.4 m/s speed of which allowed for drainage. Seedlings of the same the extraction fan in the present tests. Several other maturity (two weeks old) collected from a nursery were factors which affect pad performance including surface transplanted to the two troughs. The crops in each area of the pad, pad thickness, size of perforation of the trough included 3 plants of 535 variety roma tomatoes pads, relative humidity of air passing the pad, volume of (Solanum lycopersicum 'Roma'); 3 plants of bronze water used and number of layers may also have lettuce (Lactuca saliva Mignonette Bronze); and 3 plants contributed to the lower values obtained (Sreeram, of pak choi (Brassica rapa spp. Chinensis). 2014). The troughs were manually watered every day at 9.00 a.m. at the rate of 9 Litres day' for the three weeks 5.2 Temperature and Humidity in the Ambient Air of testing. A fungicide (Carbendazim, 50SC) was and in Greenhouses A and B sprayed onto the leaves of each plant weekly. Plant Figures 4 and 5 show the average daily temperature and heights, and stem diameters were measured three times a humidity of the ambient air as well as those in week with a ruler and Vernier caliper respectively. Leaf Greenhouses A and B during the crop growth test period, areas of each plant were measured using a grid paper. respectively. The ambient temperature and humidity as well as those for the greenhouse with natural ventilation were measured with a digital thermo.hygrometer, while those for the CEA greenhouse were recorded by temperature and humidity controllers. Readings of temperature and humidity were taken from 9.00 a.m. to 12 noon, as well as from 1.00 p.m. to 4.00 p.m. every two days. —e—Asobtout 5. Results and Discussion —e— nub use —•—• Crime/souse 5.1 Saturation Effectiveness and Temperature Difference Table I shows the saturation effectiveness of the evaporative cooling pad and the temperature difference 5 10 15 20 between the ambient air and inside of CEA greenhouse Days of testing (Greenhouse A). The average saturation effectiveness Figure 4. Temperature of the ambient air and inside the two attained for the coconut fibre pad was 25.3% (morning: greenhouses 19% and 31.5% in the evening). The saturation effectiveness corresponds to temperature difference 65 Table 1. The temperature difference between the ambient air and 7, , 62 • inside of CEA greenhouse Period of Naming period (940 am. to 12noon Evening period f 1pm. to 4 pm.) .59 testing Temperature Saturnia, Temperature SatunOtm —4— Ambtent tains) afftrinceM effectiveness(%) L• 56 • --a—Cr entlionte A cifftr1fa (a •ff•<9i t9eIS (9) A Ci eelthotive a 0 15 MO 3.0 42 IC. 53 30 23 30.7 20 36.4 8) 20 26.7 1.0 22 9) 15 214 13 27.3 0 5 10 15 20 120 10 no 25 CO Days of testing 193 as 9.1 13 27.3 Figure S. Relative humidity of the ambient air and inside the two 193 05 100 13 210 greenhouses 13 EFTA01223099 M. Surar et at: A Confrolled Environment Agriculture Greenhousefor the Caribbean Region 14 Results show that the temperature and relative humidity variables (temperature, humidity, light intensity and air inside the CEA greenhouse (Greenhouse A) were lower movement) was responsible for the improvement in plant than those for the ambient air. growth in the CEA greenhouse. This is not surprising since the temperature and Wheeler et al. (1991) were the first to propose that relative humidity of the CEA greenhouse were controlled plant developmental response to blue light (400 — 500 via evaporative cooling and air circulation, respectively. nm) was dependent on absolute blue light for stem The reverse was obtained for Greenhouse B where the elongation in soybean. Blue wave lights affect lack of control meant that the two parameters were phototropism, the opening of stomata (which regulates a higher than the values for the ambient air. It was shown plant's retention of water) and chlorophyll production in Section 5.1 that the evaporative system was able to (Reece and Campbell, 2011). Crops in CEA greenhouse effectively reduce the temperature from ambient were grown under LED blue light. Plant stem diameter conditions by 1.6°C. Greenhouse B on the other hand changes due to both cambial growth (microstructural had no accommodation for control of air movement other layer responsible for secondary growth of stems and than natural ventilation, making the humidity higher than roots) and water content (Sevanto, 2003). With higher that in the CEA greenhouse. temperature, the plant transpires at a faster rate, causes exhaustion and lack of water retention in the stem of the 53 Plant Growth Parameters in the Two plant. Greenhouses Figure 6 shows the growth of the leaves in the three The plant parameters used to compare the performance crops during the testing period. The results followed the of the two greenhouses were plant height, plant diameter same trend as for plant height and stem diameter and leaf area. Obtaining the three parameters required discussed above, with the CEA greenhouse having much nondestructive tests. Table 2 shows the values of the larger areas for the three crops than Greenhouse B (about plant height and plant diameters of the three vegetable two and half times on the average). The best results for crops. Average growth rates for the height and diameter the CEA greenhouse were obtained for pak choi were calculated by subtracting the initial value of the followed by lettuce and then tomatoes. The values parameter from the final value and dividing by the test widened as time of testing increased showing that the period (19 days). The heights and diameters of all the differences in plant development between the two three crops were much higher in the Greenhouse A (CEA greenhouses are expected to increase as the growth greenhouse) than in Greenhouse B with natural period extends. ventilation. Shin et al. (2001) found that leaf area, stem length On the average, the average growth rates in the and stem diameter generally increased with decreasing Greenhouse A, in terms of height, were at least 1.77, temperature. Wang et al. (2014) demonstrated that LED 2.67 and 3.88 of the values in the Greenhouse B for blue light optimised photosynthetic performance by tomatoes, lettuce and pak choi, respectively. For the improving the photosynthetic rate, increasing leaf area crops, the respective values for plant diameter were 1.12, and prolonging active photosynthesis duration under low 2.4 and 55. This suggests that the CEA greenhouse was irradiance. Chlorophyll absorbs light within the range of most effective for the pak choi and least for tomatoes. 400.500 nm most effectively (red and blue light). Thus, it is evident that a combination of all the control Table 2. Growth parameters for the three crops during the test period Days alter Tomatoes Lettuce Pak choi planting Height Stem diameter Height Stem diameter Height Stem diameter (cm) (x 104 cm) (cm) (x 104 cm) (cm) (x I (fi cm) 1 11.0•!11.0 0.154/0.155 7.6/7.0 0.297/0.294 5.7/5.7 0.197/0.196 3 12.4/123 0.161/0.159 8.9/7.1 0.313/0.310 8.6/6.0 0.207/0.199 5 14.9/14.4 0.171/0.165 9.9/7.7 0.321/0.314 9.9/6.9 0.234/0.214 8 20.5/16.9 0.195/0.179 11.218.1 0.331/0.318 11.2/7.6 0.303/0.215 10 23.5/185 0.219/0.193 11.9/8.6 0.335/0.320 13.018.3 0.326/0.223 12 26.6/19.6 0.225/0.213 13.0/9.1 0.346/0.326 14.6/8.9 0.367/0.243 15 29.6/21.6 0.247/0.245 14.0/9.5 0.368/0.338 15.9/10.2 0.387/0.257 17 30.0/21.7 0.257/0.246 14.6/9.7 0.383/0.339 16.1/10.4 0.416/0.264 19 30.2/21.9 0.259/0.248 15.2/9.9 0.405/0.340 16.4/10.5 0.435/0.278 Average growth rate (cm or mm day'/) 1.01/0.57 0.0055/0.0049 0.40/0.15 0.0057/0.0024 0.97/0.25 0.238/0.0043 - Values of the growth parameters are average for the three plants in the Greenhouse A/Greenhouse B. 14 EFTA01223100 M. Sum.) et at: A Con rolled Environmem Agriculture Greenhousefor the Caribbean Region 15 parameters (height, stem diameter and leaf surface area) (a) Tomases within the CEA greenhouse were much greater than those for the naturally ventilated greenhouse. The combination of using blue LED light, evaporative cooling, and air circulation fans coupled with natural ventilation gave a significant improvement in plant growth rates in the CEA greenhouse. The total • ,(" et he se A cost for two greenhouses was about USS 600. Further titeenhetaie B work will evaluate the efficiency and cost of fully functional CEA greenhouses so as to further validate these findings. Instead of the simple on/off switches 10 IS 20 method utilised to control the CEA greenhouse Days:trier planting environment, an integrated computer control system will be investigated in future research. (b) 100 References: 90 tr• 80 Albright. I-13. and Langhans. R.W. (1996), Controlled Agriculture g 70 Scoping Study: Controlled Environment Agriculture Programme. E 60 Cornell University. Ithaca. NY 14853. Accessed June 22. 2017 50 from:httpl/www.comellcea.com/attachments/Controlled%20Env t 40 Greenhouse A ironment%20Agriculture%20Scoping%20Study%20pdf%20- 30 •eGreenhouse B %20Adobe%20Acrobat%20Professional.pdf a. 20 ASHRAE (2007). ASHRAE Handbook. Fundamentals. SI Edition. 10 American Society of Heating. Refrigerating and Air-Conditioning Engineers. Atlanta 5 tO IS 20 Dagtekin, M., Cengiz K., and Yilmaz Y. (2009), "Performance Dstyx a fter planting characteristics of a pad evaporative cooling system in a broiler house in a Mediterranean climate". Biosystems Engineering. Vol.103. No.l. pp.100-104. (C) Pak Mei DeGannes. A., Hem. K.R., Mohammed. A.. Paul. C.. Rowe. J.. 80 Sealy. L. and Seepersail. G. (2014). Tropical Greenhouse 70 Growers Manualfor the Caribbean. CARDI. Trinidad. 60 Deoraj. S.. Ekwue. El.. and Birch. R. (2015). "An evaporative 1 50 • cooler for the storage of fresh fruits and vegetables". West Indian • 40 • Journal ofEngineering. Vol.38. No.l. pp.86- 95. . .13reenbouse A EGTOP (2013). Final Report on Greenhouse Production 30 • (Protected Cropping). Expert Group for Technical Advice on 1 eGreenbouseB g 20 • Organic Production. European Commission. Brussels Accessed. I0 • June 27.2017 from: http://edepotwur.n1/414544 0 Flemming. K.. Minott. A.. Jack. H.. Richards. K. and Opal. M. 0 5 10 IS 20 (2015). "Innovative Community-Based Agriculture: A Strategy Days ark, planting far National Food Production and Security". The 2nd Biennial Community Development Partnership Forum and Exhibition. Figure 6. Values of mean leaf area for the three types of crops in Ministry of Community Development. Port of Spain. Trinidad the two greenhouse during the testing period and Tobago. July. Accessed November 22 at: http://cms2.caricom.oredocuments/B336-innovative community-based-agriculture-strategy-for-national-food-prod- 6. Conclusion and-security-by-cardi.pdf Goldammer. T. (2017). "Greenhouse Environmental Control A CEA greenhouse was designed, built and tested by Systems" Greenhouse Management: A Guide to Operations and examining the effects of different control parameters on Technology. 1st Edition. (Chapter 4). Apex Publishers. Accessed system performance and plant growth. The saturation June 27. 2017 effectiveness of the pad and temperature difference from:http://www.greenhousemanagement.com/greenhouse_mana between the ambient and the inside of the CEA gement/greenhouse_environmental_control_systemshypes_contr ol_amipment.htm greenhouse were found to be 25.3% and 1.6°C Jenson. M.H. and Maher. AJ. (1995). Protected Agriculture - A respectively. The impact of controlling temperature and Global Review. World Bank Technical Paper No. 253. humidity on the CEA greenhouse was assessed, by Washington D.C.. USA. comparing the results to those of the non.controlled Karlsson. M. (2014), Controlling the Greenhouse Environment. environment and ambient conditions. The results University of Alaska. Fairbanks Cooperative Extension Service. Accessed June 2014. from: indicated that the controlled environment provided httpsi/www.uaf.edullileskes/publications-db/catalog/anr/14GA- effective cooling and humidity reduction, whereas the 00336.pdf non•controlled environment elevated ambient Martin. C.C.G.. Bedasie. S.. Ganpat. W.G.. Orrigio. S.. Isaac. temperature and humidity conditions. Plant growth W.A.I., and Brathwaite. R.A.I. (2008). "Greenhouse Technology 15 EFTA01223101 M. Surajer at: A Controlled Environment Agriculture Greenhousefor the Caribbean Region 16 is once again washing the Caribbean. Can we ride the wave this Wheeler. R.M.. Mackowiak. C.L and Sager. J.C. (1991). "Soybean time around? Proceedings of the International Congress on stem growth under high-pressure sodium with supplemental blue Tropical Agriculture. Hyatt Regency Trinidad. Port of Spain. lighting". Agronomy Journal. Vol.83. pp.903-906. December pp. 144-152. Reece. J.B and Campbell. N.A. (2011). Biology. 9th Edition. Authors' Biographical Notes: Pearson Education. California. Sahadeo. S.. aWUC. E.I.. and Birch. R.A. (2017). "Survey and Maria Sung holds a BSc. Mechanical Engineering from The modeling of protected agriculture systems in Trinidad and University of the West Indies (UWI). with special focus on Energy Tobago". West Indian Journal of Engineering. Vol.39. No.2. pp. Engineering. She was one of the founding members of the VIVI 46-57. Student Chapter of the Institution of Mechanical Engineers Sevanto. S. (2003). Tree stem diameter measurement and sap flow (!Mesh£), serving as Class Representative from 2013 to 2014. then in Scots pine. Report Series in Physics. University of Helsinki. as Vice Chairperson from 2014 to 2015. Ms. Suraj is an affiliate Finland. Accessed on June 23. 2017 at: member of thlechE and APETE She intends to specialise in http://ethesis.helsinki.fi/julkaisutimatifysildvIchevanto/treestem.p Renewable Energy Systems. df Edwin I. Ekwue is Professor of the Department of Mechanical Shin. H.K.. Lieth, J.H., and Kim. S-H. (2001). "Effects of and Manufacturing Engineering and Deputy Dean (Research and temperature on leaf area and flower size in rose". EFFE Postgraduate Student Affairs. Faculty of Engineering. The Proceeding III IS Rose Research. Acta Horticulture. 547. ISHS University of the West Indies. St Augustine. Trinidad and Tobago. 2001 CTS OF. Accessed on June 21. 2017 from: He is Vice-Chairman of the Publication Board and former Associate httpitlieth.ucdavis.edutpubtPub0413_ShinLictliKim.pdf Editor of the West Indian Journal of Engineering. His specialty is in Sreeram. V. (2014). Factors affecting the Performance Water Resources. Hydrology. Soil and Water Conservation. Characteristics of Wet Cooling Pads for Data Centre Drainage and Irrigation. His subsidiary areas of specialisation Applications. Texas. MSc. Thesis. The University of Texas. are Structures and Environment. Solid and Soil Mechanics. where Arlington. Accessed June