Sufficiency of Atmospheric Sulfur for Maximum Crop Yields

The annual fall of sulfur in rain, snow, and dust in Minnesota has been found to vary from a maximum of more than 100 pounds an acre in Minneapolis to a minimum of less than five pounds in a sulfur-deficient area in the northern part of the state. Where the collection of the water for analysis was made in vessels entirely or partly of a metal subject to attack by sulfur dioxide erroneously high values were found, the sulfates formed between rains on the interior metal surfaces being washed down into the collector and appearing as though brought down in the precipitation. An appreciable amount of sulfur dioxide was found in the atmosphere even in the most remote and most sulfur-deficient areas of the state. Its relative concentration was determined by absorption on a surface coated with lead peroxide. The amount absorbed in the course of twelve months per acre of exposed surface varied from more than 400 pounds of sulfur in minneapolis to less than five pounds near the headwaters of the Mississippi rivers. The absorption of sulfur dioxide by soils was found to roughly parallel its absorption by lead peroxide, but likely to furnish less sulfur to cropsmore » than that brought down by the precipitation. It is computed that the sulfur dioxide absorbed by the leaf tissue of plants in sulfur-deficient areas will be of even much less significance than that absorbed by the soil.« less