Greenhouse Evaluation of Elemental Sulfur and Gypsum for Flooded Rice1
- S. H. Chien,
- D. T. Hellums and
- J. Henao2
Recently, S deficiency has become a problem in many flooded soils for rice (Oryza sativa L.) production because of the increased use of high-analysis of N and P fertilizers that do not contain S. The objective of this study was to compare the relative agronomic effectiveness (RAE) of powdered elemental S and urea-S melt (prilled or powdered) to that of gypsum in a pot trial using an S-deficient Josephine soil (fine-loamy, mixed mesic, Typic Haplozerults). The RAE value of powdered elemental S for grain yield was 78% with respect to gypsum when both fertilizers were surface broadcast onto the soil surface at rates up to 40 mg S kg−1. Prilled urea-S melt was found to be significantly less effective than powdered urea-S melt in terms of increasing rice grain yield at a rate of 20 mg kg−1. Placement of urea had no effect on rice response to elemental S for a given S placement method. The various S placement methods demonstrated the following order of agronomic effectiveness of elemental S: surface broadcast = incorporation > deep placement. Rice response to gypsum, on the other hand, was found to be the same, irrespective of placement method. Prilled urea-S melt was approximately 61% as effective as gypsum in increasing rice grain yield when incorporated into the soil at 20 mg S kg−1.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © .