Transformation and Fate of Seed-Placed Sulfur Fertilizers in Presence of Plants in Two Different Soil Zones in Saskatchewan.

Sulfur is an essential plant nutrient and sulfur fertilizers are important to increase the supply of plant available sulfur in soil. Several studies have examined the relative plant availability of sulfur fertilizer sources after application, few investigations have been conducted to reveal the specific transformations that different sulfur fertilizers undergo in the soil from the application to crop uptake. Our objective was to use Synchrotron-based S K-edge X-ray absorption near-edge structure (XANES) spectroscopy to to identify the different sulfur species present in soil after amendment with S fertilizer in two different prairie soils.

Canola crop (Brassica napus) was grown in a Brown and Black Chernozem soil in Saskatchewan, Canada. The five different sulfur fertilizers were applied in the seed row at rates of 20 kg S ha^-1 . Soil samples were collected from the seed row at one, four and eight weeks after seeding in all treatments and made composite soil sample foe each treatment. Total and extractable sulfate was measured in all cores and XANES study was performed at the Canadian Light Source in Saskatoon, Canada.  Spectroscopic results revealed that different sulfur fertilizer behaved differently and eventually transformed into inorganic sulfate forms.