Sulfur/sodium bentonite prills as sulfur fertilizers. 2. Effect of sulfur-sodium bentonite ratios on the availability of sulfur to pasture plants in the field

Sulfur/sodium bentonite prills containing 5–40% of sodium bentonite were evaluated in a field experiment to determine the effects of the bentonite contents on their ability to supply sulfur to pasture plants. Comparative rates of oxidation of the elemental sulfur in the fertilizers to sulfate were deduced from plant sulfate contents and phosphate-extractable sulfate in soil (0–75 mm depth) over a period of 15 months. In grass-dominant pastures plant sulfate appeared to be more sensitive than soil sulfate to differences between S fertilizers.