Global Advanced Research Journal of Agricultural Science (GARJAS) ISSN: 2315-5094
September 2015 Vol. 4(9): pp. 501-516
Copyright © 2015 Global Advanced Research Journals

Full Length Research Paper

Development of Drying System for Dew Harvesting: A New Approach to Collect Water Supplement for Grazing Plants in Arid Regions

Mohamed I. Al-Zarah

Environmental and Natural Resources Dept., College of Agricultural and Food Sciences, King Faisal University, Al-Hassa, Kingdom of Saudi Arabi.

E-mail: malzarah@kfu.edu.sa; Tel: +966 505920920; fax: +966 5801778.

Accepted 15 September, 2015

Abstract

Passive dew harvesting and rainwater collection requires very small financial investment, hence has the potential to exploit a free and clean source of water in rural areas. The increase of livestock production in Saudi Arabia has resulted in a parallel increase in demand for grazing plants and hence greater exploitation of ground water for irrigation. The current trends in water conservation policies, necessitates finding alternate sources of water to provide minimum grazing requirements. Dew condensation on greenhouse dryer cladding and assorted other surfaces was frequently noticed. Accordingly, this study was performed to measure the quantity of condensation in arid regions. Dew was measured by using (I) glass of flat plate solar collector, (II) tempered glass of photovoltaic (PV) and (III) double sloped (25°) acrylic plexiglas of greenhouse dryer. The total amount of dew was measured during the years 2013/2014in Alahsa, Saudi Arabia. The condensate dew drops were collected naturally (before scraping) and by scraping once and twice. Dew began to condense mostly between 12:00 am and 6:30 am and its intensity reaches its peak at about 45 min before sunrise. The collected dew and rain water were applied to Atriplexhalimus species for two years. Dry matter, forage yield and survival percentage were recorded. The cumulative dew yield on double-sloped test roof varied with wind speed and direction. Results indicated that wiping twice gave more dew yield compared to one wiping or collection by gravity. Dew and rain pH were neutral (close to 7) and the total mineralization was appropriate. The ions concentration is as per standard of World Health Organization for potable water. The highest average survival percent of Atriplexhalimus was 98.8% in winter but decreased as time progressed. It was 99.9% in the first year. Atriplexhalimus produced average forage yield of 2350 and 4120 kg/ha for first and second year, respectively. Using existing drying system for dew and rain harvesting could provide a potable water source for arid region.

Keywords:  PV module, flat plate solar collector, greenhouse, drying system, dew collection, water vapor, rain water harvesting, irrigation, Atriplexhalimus species.