Magnesium Fertilizers

Magnesium Fertilizers 

fertilizers containing magnesium. Among the magnesium fertilizers are magnesium-potassium concentrate, containing 8-9 percent MgO and 17.7-19.0 percent K₂O; epsomite (industrial MgSO₄), containing not less than 17.7 percent MgO; ammoschoenite, (NH₄)₂SO₄-MgSO₄-6H₂O, containing 10 percent MgO and 7 percent N; dolomite-ammonium nitrate, a mixture of CaMg(CO₃)₂ and NH₄NO₃, containing about 10 percent MgO, 17 percent N, and 14 percent CaO; serpentinite (finely pulverized rock), containing 32-43 per-cent MgO; and calcined magnesia, containing not less than 89 percent MgO, and also dolomite, fused magnesium phosphate, dunite, potassium magnesium sulfate, and kainite. The standard quantity of magnesium fertilizer applied to acid sandy and sandy-loam soils, which are particularly deficient in magnesium that is available to plants, is 20-40 kg of MgO per hectare. Magnesium deficiency is readily detected by observing certain characteristic external indications of crops.