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.