Kj. Hailes et al., MAGNESIUM IN TROPICAL AND SUBTROPICAL SOILS FROM NORTH-EASTERN AUSTRALIA .2. RESPONSE BY GLASSHOUSE-GROWN MAIZE TO APPLIED MAGNESIUM, Australian Journal of Soil Research, 35(3), 1997, pp. 629-641
A glasshouse trial, in which maize (Zea mays L. cv. Pioneer 3270) was
grown in 35 north-eastern Australian soils of low magnesium (Mg) statu
s, was undertaken to study the response to applied Mg. Of the soils st
udied, 20 were strongly acidic (pH(1:5 soil:water) <5.4), and in these
soils the response to Mg was studied in both the presence and absence
of lime. Magnesium application significantly (P < 0.05) increased dry
matter yield in 10 soils, all of which were strongly acidic. However,
significant Mg responses were recorded in 6 soils in the presence of
lime, indicating that, in many situations, liming strategies may need
to include consideration of Mg nutrition. Critical soil test values fo
r 90% relative yield were 0.21 cmol(+)/kg of exchangeable Mg or 7% Mg
saturation, whilst the critical (90% yield) plant tissue Mg concentrat
ion (whole shoots) was 0.15%.