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Dilip Nandwani Page 1 March 30, 2013 MICROIRRIGATION FOR SUSTAINABLE VEGETABLE PRODUCTION IN THE US VIRGIN ISLANDS Dilip Nandwani, PhD Principal Investigator March 30, 2013 Water Resources Research Institute University of the Virgin Islands Dilip Nandwani Page 2 March 30, 2013 Disclaimer The research on which this report is based financed in part by the U.S. Department of the Interior, United States Geological Survey, through the Virgin Islands Water Resources Research Institute. The contents of this publication do not necessarily reflect the views and policies of the U.S. Department of the Interior, nor does mention of trade names or commercial products constitute their endorsement by the United States Government. Acknowledgments I wish to thank a number of persons and acknowledgments to:
Horticulture program team Ms. Vanessa Forbes, Paulino (Papo) Perez and Victor Almondover for providing assistance in the field and data collection.
My sincere appreciation to Dr. Joey Williamson, Entomologist (CES) for scouting field and assistance in insect pests control.
Dr. Robert Godfrey for providing rainfall data. Dilip Nandwani Page 3 March 30, 2013 ABSTRACT The main water delivery system for crops grown for both research at the University of the Virgin Islands and by many of the territory of the U.S. Virgin Islands farmers is through drip irrigation. During this time there is no water shortage problem; however the US Virgin Islands experiences drought from January through March, normal dry season. Through the use of drip irrigation we have been able to conserve fresh water which is truly a valuable resource. Chemigation and fertigation through drip irrigation delivers pesticides and fertilizer in the root zone of the plants, respectively. The precision obtained through drip application is safer, more accurate and uses far less material due to the accuracy. The objectives of the project were to evaluate improved water management practices using microirrigation in selected vegetables and determine varying rates of irrigation on the yield and growth of selected vegetables. Replicated trials on cucumber, eggplant and tomato were conducted in field plots at the University of the Virgin Islands Agricultural Experiment Station, Albert A. Sheen campus and at the Sejah farm, Kingshill. Water was applied to maintain soil moisture levels equivalent to -0, 40, 60 kPa using tensiometers. Moisture level -30pka produced highest yield compared to -60pka and -90pka. -90pka moisture level was high and produced low marketable fruits in cucumber. In eggplant, var. ‘Hansel’ produced highest yield (30.57ton/ha) and lowest in ‘Magal’ (12.16ton/ha). Spider mites infestation (2-3%) occurred in plots and controlled by miticides. All four varieties of tomato produced marketable fruits. Trial needs to be repeated in order to collect data and results. The duration of project was short to conduct the detailed research necessary to achieve all the three objectives. Frequent rainfall and insect pests damage was an issue and trial needs to be repeated in order to collect data and results. Water is a rare commodity on a semiarid island and the Virgin Islands stakeholders are concerned to use this precious resource as efficiently as possible. Drip irrigation has been very beneficial and fertigation and chemigation are new technologies for utilizing a drip irrigation system to apply fertilizer and pesticides. Data being analyzed to determine significance differences among treatments and second trial is planned this year. Dilip Nandwani Page 4 March 30, 2013 TABLE OF CONTENTS Page No. INTRODUCTION 5 PROBLEM DESCRIPTION 5 Objectives METHODOLOGY 6 PROJECT FINDINGS 7 CONCLUSION 8 LIST OF PUBLICATIONS AND PRESENTATIONS 8 STUDENT PARTICIPATION 9 BIBLIOGRAPHY 10 APPENICES: Appendix 1 11 Appendix 2 12 Appendix 3 13 Appendix 4 14 Dilip Nandwani Page 5 March 30, 2013 Introduction The main water delivery system for crops grown for both research at the University of the Virgin Islands and by many of the territory of the U.S. Virgin Islands farmers is through drip irrigation. During this time there is no water shortage problem; however the US Virgin Islands experiences drought from January through March, normal dry season. Through the use of drip irrigation we have been able to conserve fresh water which is truly a valuable resource. Energy required and associated costs to desalinate large quantities of water for farming purposes is truly substantial. Through the use of drip irrigation, researchers and farmers alike have been able to utilize above ground water storage tanks as well as water catchment ponds to store large quantities of rain water in the rainy season. Problem and Research Objectives The use of drip irrigation is a great asset when it comes time for the application of fertilizers. Unlike the common local application of granular fertilizer, which is spread around the field or around the base of a sizeable plant, drip irrigation affords the efficiency of applying water soluble fertilizers within inches of a relatively newly planted seedling and throughout the life of the plant. This allows for remediating specific nutrient deficiencies that can occur in local high pH calcareous soils. Chemigation through drip irrigation delivers pesticides in the root zone of the plants. The precision obtained through drip application is safer, more accurate and uses far less material due to the accuracy. Using pesticides such as DuPont Coragen, Venom other commercial pesticides and soluble fertilizers are more efficient use of drip irrigation which saves in labor costs. Objectives a) Develop and evaluate improved water management practices using microirrigation in selected vegetables. b) Evaluate the effect of varying rates of irrigation on the yield and growth of selected vegetables. c) Determine the minimum water requirements for selected vegetables. Dilip Nandwani Page 6 March 30, 2013 Methodology • Three experiments were conducted in field plots at the University of the Virgin Islands Agricultural Experiment Station, Albert A. Sheen campus and at the Sejah farm, Kingshill. Cucumber and eggplant trials conducted at the UVI-AES field plot in the growing season of 2012 and tomato trial conducted at Sejah farm, Kingshill in the growing seasons of 2012-2013. • Seeds, potting trays, potting mix and drip supplies ordered off-island and locally after approval of project and project account establishment. • An advertisement for the student aid prepared, circulated and applications invited for the position. Interviews conducted and a UVI Undergraduate student Ms. Vernecia Philips was hired. Ms. Philip didn’t complete her appointment period, therefore, another student aid Mr. Mark Sinanan of UVI hired. • Seeds of cucumber var. `Eureka’ planted in ‘seedling trays’ containing potting mix in the greenhouse. Seedlings were transplanted in the field approximately 10 days after germination. • An experimental plot (90’x75’) selected at the USDA field and cucumber transplants planted in three rows spaced 1.2 m apart, with 12 plants per row spaced at 0.6m along the row. The experimental design was randomized complete blocks, with 3 replications. Standard conventional system applied for the production e.g. fertilizer applications, planting densities and pest control. Microirrigation: Water was applied to maintain soil moisture levels equivalent to 20, 40, 60 kPa. Tensiometers were placed at a depth of 15 cm, in the middle rows of plots, to monitor soil moisture in the plant root-zone. The irrigation system monitored daily and turned on when tensiometer readings exceed the specified level for each treatment. • The weather station at the University of the Virgin Islands- Agricultural Experiment Station used to provide the necessary meteorological data for irrigation scheduling. • Data were collected on rainfall, water used, yield, and other plant characteristics. • In eggplant, three cultivars ca. ‘Nadia’, ‘Hansel’ and ‘Magal’ were grown in conventional management system at the Agricultural Experiment Station of the University of the Dilip Nandwani Page 7 March 30, 2013 Virgin Islands in St. Croix (Kemble et.al., 1998) • The experimental design was complete randomize block in three replications. Weed control was done mechanically or with herbicide application. • Data on plant height, marketable yield and fruit size were recorded. • At the Sejah farm, field plot (30’x152’) selected, cleared and prepared for the tomato experiment. Untreated seeds procured from Harris seeds, NY and planted in compost in the greenhouse and other cultural practices adopted as per National Organic Program (NOP). • A randomized complete block design with three replication used. Four cultivars of tomato (determinate type) `Mountain Fresh’ (MF), `Red Defender’ (RD), `Security 28’ (SY) and `Defiant’ (DF) used for the experiment. Tomato transplants of all four cultivars (4-5 weeks) planted in the field. • OMRI listed fertilizers and insecticides ordered and applied. Drip irrigation (low pressure, gravity based) used and water requirement monitored. • Data on yield (numbers and total weight) and marketable fruits collected from multiple harvests throughout the growing season. Principal Findings and Significance • Moisture level -30pka produced highest yield compared to -60pka and -90pka. -90pka moisture level was high and produced low marketable fruits. • Injecting Malathion, Sevin or Venom on a rotation as needed once the pest reaches levels were they can no longer be controlled using topical application, often bring the situation under control. • In eggplant, var. ‘Hansel’ produced highest yield (30.57ton/ha) and lowest in ‘Magal’ (12.16ton/ha). Average marketable fruits number was higher (14/plant) in `Hansel’. Spider mites infestation (2-3%) occurred in plots and controlled by miticides. • All four varieties of tomato produced marketable fruits. Trial needs to be repeated in order to collect data and results. • In tomato trial, total 18,750 gallon water used in drip irrigation from December 2012 to Dilip Nandwani Page 8 March 30, 2013 March 2013 (Dec. 2012-2400gal, January 2013-4950gal, February 2013-6100gal, March 2013-6300gal). • Frequent rainfall and insect pests damage was an issue and trial needs to be repeated in order to collect data and results. • Water is a rare commodity on a semiarid island and the Virgin Islands stakeholders are concerned to use this precious resource as efficiently as possible. Fertigation and chemigation are new technologies for utilizing a drip irrigation system to apply fertilizer and pesticides. Conclusions • Drip irrigation has been very beneficial though it has not been easy to get 12 or 15ml drip tape. Regional supplier have only been able to get 8ml and 10 ml low flow drip tape, the 15ml is very difficult to obtain and generally has to be ordered off-island which can be very pricy once shipping to the Virgin Islands is added. • Frequent rainfall and insect pests damage was an issue in cucumber and trial needs to be repeated in order to collect data and results. • Water is a rare commodity on a semiarid island and the Virgin Islands stakeholders are concerned to use this precious resource as efficiently as possible. Fertigation and chemigation are new technologies for utilizing a drip irrigation system to apply fertilizer and pesticides. • The study provided vegetables yield response with respect to irrigation amounts and method of determination of amounts and would be useful to producers for planning purposes and water management of the crops. Data being analyzed to determine significance differences among treatments. List of Publications and Presentations 1. Nandwani D. Evaluation of sandea for weed control in transplanted eggplant. American Society for Horticultural Science-Southern Region, Orlando, FL, 2013 (poster) Dilip Nandwani Page 9 March 30, 2013 2. A manuscript shall be prepared on tomato after data analysis for submission to peer review journal. Student Participation Two student aids worked in the project: 1) Vernecia Philips (UVI, Undergraduate) 2) Mark Sinanan (UVI, Undergraduate) Dilip Nandwani Page 10 March 30, 2013 Bibliography 1. 2007 USVI Census of Agriculture. 2009. US Department of Agriculture. 2. Byer M., Simpson C.O. and H. A. Williams 1992. Hot pepper production in Barbados. Ministry of Agriculture, Food and Fisheries, Barbados. P. 3 3. Charles B., Christopher L., and M. Murata. 1996. Simple microirrigation techniques for improving irrigation efficiency on vegetable gardens. Agricultural Water Management Vol. 32 (1), 37-48 4. Christian G. II, Katinka W., Srun S., Mong V., E. C. Yarith, 2006. Postharvest loss in the supply chain for vegetables –The case of tomato, Yardlong Bean, Cucumber and Chinese Kale in Cambodia. AVRDC Working Paper 16, AVRDC, Shanhua, Tainan. P 1-52. 5. Lamm F.R, and C.R Camp. 2007. Subsurface drip irrigation. In: Microirrigation for Crop Production, 473-551. F. R. Lamm, J. E. Ayars, and F. S. Nakayama (eds). New York, N.Y.: Elsevier. 6. Navarro A.A. 1987. Determination of the minimum irrigation requirements of tomatoes. Virgin Islands perspective. 2: 24-27. 7. Navarro A.A. and J. Newman. 1989. Two drip irrigation rates and two emitters on tomato production. J. Agric. Uni. Puerto Rico 73: 23-29 8. Palada, M.C., Crossman S.M.A and C.D. Collingwood. 1993. Irrigation water use and yield of thyme in the Virgin Islands. Proceedings of the Caribbean Food Crops Society, Fort de France, Martinique. 29: 522-530 9. Palada, M.C, Crossman S.M.A and C.D. Collingwood. 1995. Improving vegetable production using microirrgation in the Virgin Islands. Pp. 502-509. In: F. Lamm (ed.) Microirrigation in the changing world. Conserving water resources/preserving the environment. Proc. 5th Int’l Microirrigation Congress. Orlando, Florida, ASAE 4-95 10. Robert G. E., I-Pai Wu, and A. G. Smajstrala. 2007. Micoirrigation systems. In: Design and Operation of Farm Irrigation Systems. Glenn J. Hoffman, Robert G. Evans, Marvin Eli Jensen and Derrel L. Martin (eds.) American Society of Agricultural and Biological Engineers, p 632-683 Dilip Nandwani Page 11 March 30, 2013 Appendix 1 Table 1. Cucumber production in varying rates of irrigation and soil moisture. Soil moisture (pka) No. of fruits Total fruit wt. (gm) Marketable fruits Marketable fruit wt. (gm) 20 126 22,016 93 18701 40 111 19,909 87 17675 60 138 26,542 111 23384 Table 2. Fruit characteristics of cucumber in various moisture level Soil moisture (pka) Fruit diameter (cm) Fruit length(cm) 20 3.58 11.72 40 3.49 12.56 60 3.80 12.94 Fig.1. Tomato production in drip irrigated plot at the Sejah farm. (Var. MF, `Mountain Fresh’; RD, `Red Defender’; SY `Security 28’, DT, `Defiant’) Dilip Nandwani Page 12 March 30, 2013 Appendix 2 Fig 2. Total fruit weight per plant of four var. of tomato at Sejah farm Fig.3. Yield in tomato grown at the Sejah farm Dilip Nandwani Page 13 March 30, 2013 Appendix 3 Annual Rainfall on St Croix (Measured at Sheep Research Facility; Line = 25 yr average of 50.4 in) Year 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 Rainfall, in 0 10 20 30 40 50 60 70 80 Dilip Nandwani Page 14 March 30, 2013 Appendix 4 Varying rates of irrigation in cucumber Soil moisture data (tensiometer) in the field Eggplant field Low pressure irrigation in tomato at Sejah farm Tomato field ready to harvest Tomato fruit grading and data collection