Wageningen UR Greenhouse Horticulture has developed a new type of greenhouse specifically for tropical lowland areas. In Malaysia the greenhouse is now tested in a ‘proof of principle’ project. A net melon cultivation round was started in October 2010. The greenhouse protects the crop against wind, rain and insects. Plant production is prolonged and the quality of the harvested product is better.
Malaysia has made the development of horticultural production one of its spearheads for the coming years. Most horticulture is currently found in the highlands where climate conditions are most suitable. Horticulture needs to move to lowland areas because there is no room for expansion in the mountains. Cropping in those areas, however, is difficult. Temperatures are high with the possibility of heavy rainfall and strong winds. In addition, insect pressure is high. Protected cultivation in a greenhouse could possibly offer a solution provided that climate can be controlled.
Scientists of Wageningen UR Greenhouse Horticulture have now developed a new greenhouse construction that seems to meet the requirements of cropping in tropical lowland. First experiences have already been gained a number of years ago in Indonesia. A larger prototype of this greenhouse has now been constructed, together with local suppliers and automation experts of Priva. Climate and crop in the greenhouse will be monitored.
Natural ventilation
The principle of the greenhouse is based on passive cooling. The foil greenhouse has an aluminium construction; the roof is covered with a diffuse foil, the sides are made of netting and a ‘chimney’ has been built on top of the roof. The always present wind causes an upward suction through the chimney in this greenhouse resulting in a continuous air flow passing the crop. Evapotranspiration by the plants results in further cooling avoiding temperatures to run up too high.
The first plants were brought into the greenhouse in October; a locally know crop was chosen: the net melon. The plants are placed in bags with coconut fibre and cultivation is supervised by a local advisor. The researchers are using various sensors for remote monitoring of the greenhouse climate. Less spraying is needed because the nets are preventing insects to fly into the greenhouse. In case cultivation is successful, hot peppers and tomatoes will grown in the greenhouse next year.
Quality
“When all goes well this year, we will be involving local growers in the project next year. Much is still to be done on all fronts to improve cropping conditions,” says researcher Anne Elings. “I expect a lot of this project. In a greenhouse crops can be grown over a much longer period and the quality of the product shows a considerable increase. And quality is becoming increasingly important. Malaysia has enormous export potential, e.g. to Singapore. This, however, requires further development of the horticultural chain and this starts with good production conditions.”