Nutrient Uptake Patterns of Native Rhododendron Species in Korea and China under Ebb and Flow Subirrigation

摘要

Subirrigated by ebb and flow bench system in a greenhouse, analyzed and calculated by Yamazaki formula for hydroponics, the patterns of nutrient uptakes for 7 native Rhododendron species in 5 different pH treatments were outlined. N uptake was exhibited the best at pH 6.5 regime during June and July when the leaf tended to be mature and flower hud differentiation started. P appeared better absorption in the environment of lower pH. K exhibited an unusually low uptake, even the minus n/w value emergedin June and September. K seemed not so important for growth and development. Ca uptake were irregularly but Mg remained at a stable and flat absorption pattern at low levels. In general, at the beginning of pH treatment, monthly the absorption of macronutrients showed an irregular pattern, but then the uptake patterns became regular, i.e., the macronutrient uptakes in 5 pH regimes exhibited a decreasing tendency along with the rise up of pH values for the 7 species of native Rhododendron in Korea and China.