Effects of Soil Water Potential Control by Drainage Canal plus Porous Water Proof Sheet Mulching on the Fruit Quality of Satsuma Mandarin in Citrus Orchards

摘要

The experiment was carried out to determine the effect of drainage canal + reflecting sheet (porous water proof sheet, PWPS) mulching on the fruit quality of satsuma mandarin in three citrus orchards located in Hamduck, Kosan, and Namwon areas, Jeju,Korea. The 25-year-old citrus trees, which were planted densely, were thinned at alternate planting. The soil was prepared for drainage by 50 X 50 cm (W X D) canal system in March Soil was then mulched with reflecting PWPS sheet, starting from early August Soil water potential was measured at 30 cm of soil depth under tree canopy Results showed that soil water potential in Kosan district decreased very rapidly compared with those in other districts. Water potential in drainage canal +PWPS mulching plotalso decreased much more rapidly than control. Peel coloration (Hunter a value) was higher in drainage canal + PWPS mulching treatment than in control. Fruits matured earlier in drainage canal + PWPS treatment than in control Soluble solid content was highest in fruits from Kosan, 12.8°Bx, followed by that from Hamduck, 11.7°Bx, and Namweon, 11.1°Bx Acidity was higher in fruits from Kosan and Namwon compared with Hamduck, which were 1.23%, 1.51%, and 1.51%, respectively Acidity of fruit in control and drainage canal + PWPS mulching plot were 1.04% and 1.42%, respectively, indicating that acidity of fruit from reflecting sheet mulching plot was higher than that of fruit from control