The bioavailability of Al in soils to tea plants

In order to understand the relationship between forms of Al in soils and the uptake of Al from soil into tea plants, tea leaves and soils were collected from 13 tea gardens in the east of China. The Al concentration measured in the tea leaves was found to be best predicted by ‘available’ Al extracted by 0.02 M CaCl2. The relationship appears to be linear, with a correlation coefficient of 0.77 (P=0.01). The Al content of tea leaves increases with a decrease of soil pH. This relationship is non-linear with a marked increase in leaf Al for soils with pH <5.0. The amounts of Al in soils extracted with 0.02 M CaCl2 was much less than other forms of Al in soils. The amount of Al measured in the tea leaves was directly related to both the ‘available’ form of Al in the soils and soil pH. Soil pH was identified as a major factor that controls the uptake of Al from soil into the tea leaves.