The influence of porous ceramic particle size and fertigation quantity on the yield and quality of roses grown in soilless culture

To test porous ceramic ball (PCB) as a new substrate for soilless culture o f roses, the influence of particle size and fertigation quantity on the yie ld and quality of cut roses cv. Rote-rose was investigated using rockwool ( RW) as a control. The solid phase distribution in three phases of PCB was a little less than 40%, without regard to the particle size. The liquid phas e distribution was directly proportional to the particle size so that the s maller the particle size, the larger the liquid phase; for particle size ra nging from 0.5-1.5 (mm/phi) it was 47%. Phosphoric acid was less concentrat ed in the exhaust fluid of PCB than it was in the nutrient solution. A decr ease in PCB particle size increased the water capacity of the substrate whi ch resulted in heavier cut flower fresh weights and longer stems, but a sma ller percentage of dry matter. Increasing the amount of fertigation had a m ore positive influence on cut flower fresh weight, stem length, and leaf ar ea than did the increase in water capacity of the substrate. However, neith er the water capacity of the substrate nor the fertigation quantity had lit tle influence on the yield of cut flower. Compared to PCB particles, when R W was used for substrate, both the quantity and quality of the cut flowers were decreased. Moreover, the vase life of cut flower grown on RW was short er than that on PCB. It was concluded that the optimum particle size of PCB for soilless culture of roses ranged from 0.5 to 4.5 (mm/phi). With this s ubstrate setted approximately 2.5 liter/plant, the amount of fertigation fo r each rose plant per day estimated 900 ml during the summer and 450 ml in winter, When the waterlogging was combined, decreasing the amount of fertig ating by half of standard did not cause any ill-effect on the quality of cu t flower in autumn and winter so the practice was considered to be effectiv e.