Low soil pH is also associated with a low supply or depletion of magnesium, possibly due to
leaching; however, research suggests that impairment of root growth in acid soils (pH 4.3 to 4.7) also may hinder magnesium absorption
(67). In one study
(65), low soil pH
(3.0) resulted in
increased accumulation of magnesium in the shoots, but decreased accumulation in the roots.
Contradicting Marler
(65) and Tan et al.
(67), Johnson et al.
(70) found no clear correlation between
low soil pH and magnesium accumulation.
Relatively high and low root-zone temperatures affect magnesium uptake, but the degree of
impact may be influenced by plant type and stage of plant development. Huang et al.
(71) and
Huang and Grunes
(68) reported that increasing root-zone temperature (10, 15, 20°C) linearly
increased magnesium accumulation by wheat seedlings that were less than 30 days old but suppressed
accumulation by seedlings that were more than 30 days old. Similarly, magnesium uptake
decreased when temperatures in the rhizosphere decreased from 20 to 10°C
(69).