Available Boron

Available boron, measured by various extraction methods, in agricultural soils varies from 0.5 to 5 mg kg^-1. Most of the available boron in soil is believed to be derived from sediments and plant material. Gupta (46) reported that available boron on Podzol soils from eastern Canada ranged from 0.38 to 4.67 mg kg^-1. Few studies have been conducted that attempt to identify solid-phase controls on boron solubility in soils. Most of the common boron minerals are much too soluble for such purposes (48).