Описание: The study details the water management of hydroponically grown honeydew melon in tropical greenhouse using automatic controller. Nutrient solution was applied at two flow rates and three levels of application intervals to melon grown in three locally-available media to assess the growth and yield response. Water productivity and economic feasibility of the system were also evaluated. Results revealed that rice hull and pumice comparably produced larger, heavier and sweeter fruits than fresh coco peat. The flow rates of 1 L/hr and 3 L/hr showed comparable performances. However, nutrient solution when applied 24 times for 15 minutes performed relatively well and significantly affected the growth and yield of the melon than when applied 6 times for 30 minutes and 3 times for 30 minutes. Water productivity was higher in melons planted in rice hull with flow rate of 1 L/hr and application interval of 3 times for 30 minutes. Break-even point was equal to 1,014.43 kg/yr or only about 24 percent of the potential yearly harvest. It was concluded that in hydroponic melon production, automatic controller can simplified water management while supplying uniform and regular nutrient solution.
Описание: The system was governed by the principle of “one-pump rule” where culture water was recirculated by a 40-watt pump in a closed loop. The design prevented the system from failure and collapse since only one pump lifted the water from the bio-filtration tank, the lowest section, to the fish tank, the highest section, and allowing water to flow by gravity along the raceway and return pipe network and back to the bio-filtration tank. The system generated good water quality having 5.6 parts per million average dissolved oxygen at 100 per cent average saturation and 21.4°C average temperature with 7.1?7.5 pH and 250?390 parts per million total dissolved solids. After a 108-day growing season, 71 pieces of Nile tilapia weighing 22 kilograms and 208 heads of freshwater prawn weighing 1.137 kilograms were recovered while 500 pieces of vegetables with 180 kilograms salable weight were harvested. The system consumed 5,225 liters of water which included 10 per cent evaporation losses. The system was able to utilize and added more value to limited resources such as water, electricity and space by producing more food in one system and structure.
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