Investigation of Colony Forming Unit (CFU) of Microorganisms in the Paprika-grown Greenhouses Using Open and Closed Soilless Culture Systems

This study was conducted to compare colony forming unit (CFU) of microorganisms in closed and open soilless culture systems for estimating the possibility for potential disease occurrence. Samples were collected at four different positions in four commercial greenhouses with closed or open soilless culture system using rock wool or coir as substrate, respectively. The dist ance between sampling positions was 3 cm starting from the substrate and the surface area of each position was 25 cm 2 . The CFU of fungi was significantly higher in the open system, while that of bacteria was not significantly different but showed relativ ely lower in the closed system. Samples collected at the plastic surface of the substrates where little environmental effects occur red from drainage showed lower CFU than any other positions. The principal component analysis showed that samples collected on the drainage pathway highly affected the changes in microbial population in the greenhouse. These results indicated that greenhouseswith closed soilless culture are expected to have more advantageous conditions for restraining the microbial growth, resulting in the lower potential of disease occurence in greenhouse ecosystem.Additional key words