Sulfur Nutrition-Like Nitrogen, but Different
Both sulfur and nitrogen are critical for protein development and for chlorophyll production so one may assume that both nutrients are required at the same time and react similarly in the plant. However, this is not completely correct. One major factor to consider is that nitrogen is quite mobile in the plant while sulfur is not. There is relatively little redistribution out of the leaf. Couple that with the fact that much of the nitrogen, at least 75%, is taken up prior to flowering while the corn plant still needs 50% of its sulfur after flowering. A 230 bushel corn crop takes about 25 pounds of sulfur to fill the ear so much of this has to be taken up after pollination. This means that we need sulfur available for root uptake during grain fill and we need actively growing roots at that time to be able to absorb the sulfur. In sandy soils this may mean providing additional sulfur through fertigation later in the season. In heavy soils having adequate sulfur in the sulfate form in the soil profile is critical. Gypsum is a good source of plant available sulfate sulfur and if you apply 1 ton of PRO CAL 40 you will get about 300 pounds of sulfur, enough sulfur to meet your crop needs for this crop, plus additional years.