DEPARTMENT OF AGRICULTURE 27

 Calcium: Calcium is used in sizable quantities by the tobacco
plant. Where this element is very low in the soil, or where the
pH is below 5.2, it is recommended that adjustments be made
through the application of dolomitic limestone. The amount
to be added should be determined by soil analysis. The fertilizer
should contain calcium in an available form in an amount
equivalent to a minimum of 60 pounds of CaO per acre. Most
of the commercial grade fertilizers supply the needed calcium
on soil of suitable pH. Liming practices for tobacco soils
have already been discussed. Soils with a pH above 6.2
are generally not recommended for tobacco.
 Magnesium: Magnesium is a constituent of chlorophyll. Car-
bohydrates cannot be manufactured in the absence of this
material. The fertilizer should contain magnesium in an avail-
able form (at least one-half water soluble in the mixed fer-
tilizer) in an amount equivalent to 20-30 pounds of magnesium
oxide per acre.
 Sulfur: Seventy-five to one hundred pounds per acre of SO3
equivalent in an available form is sufficient. There is a siz-
eble tolerance in the amount of sulfur that may be applied.
Calcium sulfate's solutility is so great that in areas of heavy
rainfall, an appreciable amount is lost through leaching. The


Fig. 14: Shows the Toxic Effects of Chlorine on Leaf. Note Curled Leaf
Margins. Left-40 Pounds Chlorine per acre. Right-20 Pounds Chlorine
 per acre