Development of suitable greenhouse to increase melon production efficiency

Abstract

This research aims to develop a greenhouse, which suitable for increasing melon production efficiency by developing ventilation of the new greenhouse to be better than the primitive greenhouse; semi-circular greenhouse (farmer’s greenhouse).  The new greenhouse has overlap curve roof with overhead opening is designed for cooling down temperature in the greenhouse. Temperature and relative humidity in the greenhouse are controlled close to the outside by a control system and the automatic fan activated when the temperature reaches 40 °C. The greenhouse is, 30.0 m. long ,6 m. wide, 3.0 m. high of pole and 1.5 m high of roof. The structure is galvanized steel pipe. The roof is covered with plastic 150 microns thick, the 32-mesh net used for the side walls. The construction costs less than 100,000 THB per unit, exclude fertilizer, irrigation systems, automatic temperature and humidity control systems along with ventilation fan set. The temperature measurement in the new greenhouses shown that the temperature decreases 5 - 15 °C when the inside air is ventilated by fan system, moreover in a sunny day that temperature reaches 40 °C, the automatic fan system reduces temperature to 37 °C. The melon variety used in this experiment is the Morakot variety, which is a popular melon variety consumed in Thailand. In terms of productivity, it was found that the greenhouse had an average total yield of 512 kg, an average income of 26,327 THB and a net profit of 6,633.21 THB per production cycle. Meanwhile, the farmer's greenhouse has an average total yield of 476 kg, an average income of 24,720 THB and a net profit of 2,692.88 THB per production cycle. The sweetness of the melon form both types of greenhouses pass the standard. The greenhouse has an economic break-even point of 3.36 years with the lifetime of 10 years, while the farmer’s greenhouse has the break-even point of 3.21 years with the lifetime of 5 years.