EVALUATION OF IRRIGATION SYSTEM BY BALANCE AND INTEGRATED SOLAR RADIATION ON THE FRUIT QUALITY OF MUSKMELON IN CLOSED PERLITE CULTURE SYSTEM

Three types of irrigation treatments were set up to evaluate the irrigation management by hanging balance and integrated solar radiation (ISR) in closed perlite culture system. Two irrigation regimes were controlled by hanging balance at two drainage rates; high and low level were between 10~15% (dr-H) and 1~5% (dr-L) respectively. Another regime was controlled by specific ISR of 576 kJ•m^-2. The weighing system could control the amount of irrigation accurately up to 0.05kg. The amount of irrigated solution by balance was high in dr-H and low in dr-L. The amount of irrigated solution by ISR was more on the day of daily ISR of 16.6 MJ•m^-2 than 11.3 MJ•m^-2. The water content (%) in perlite controlled by balance was steadily maintained on the level of 26% in dr-H, and 22% in dr-L during the irrigation period, whereas the water content (%) in perlite controlled by ISR varied greatly between about 23 to 26%. Drainage rate was very different among treatments as 14.3% in dr-H and 51% in ISR-576 on the day of daily ISR of 11.3 MJ•m^-2. Soluble solid content was high in ISR-576 and low in dr-L. Fruit fresh weight was higher in dr-H than other treatments. Accordingly irrigation management by balance in perlite culture in a closed system seems to be good for fruit quality and economic use of water and nutrient solution.