Visual and Physiological Symptoms
Soil Physical and Chemical Properties That May Favor Magnesium Deficiencies:
Notes on Soil Complexity
Plant Mineral (Tissue) Analysis
Table 1. Critical magnesium (Mg) ranges for several physiological growth stages in corn
(Lockman,1969)
a Whole plant sample taken 24 to 45 days after emergence
b 3rd youngest fully collared leaf taken 45 to 80 days after emergence
c Plant tissue sample taken from ear leaf (green silk to dent)
Table 2. Some critical nutrient values for corn ear leaves silking / tasseling
(Jones and Eck, 1973)
When a magnesium deficiency is conclusively identified remedial and preventive treatments may be needed.
Figure 1. Relative availability of magnesium, calcium, and iron in low CEC soils. Even at close to optimum pH levels, magnesium can still be unavailable in some situations
Table 3. Recommended magnesium application rates and methods (Spectrum Analytic, 2010)
Table 4. Fertilizer sources and magnesium (Mg) percentage by weight (Spectrum Analytic, 2010)