Sulfur Response by Alfalfa (Medicago sativa L.) on a Sulfur-Deficient Soil1
- E. C. Seim,
- A. C. Caldwell and
- G. W. Rehm2
Field experiments were conducted in a S-deficient area in Minnesota to determine the soil S status, atmospheric contributions of S, and the response of alfalfa to S fertilization. In general the sulfate — S, the available S, and the reserve and total S in the soil were higher than is normally expected in S responsive soils. The average annual addition of S to the soil from atmospheric sources was 5.4 kg/ha (4.8 lb/acre) at the rural experimental site and 27.4 kg/ha (24.4 lb/acre) at a metropolitan area site. Alfalfa responded to all S treatments regardless of the material source. Treated plots yielded three times as much alfalfa as the check plots. Increases were obtained from residual as well as annual applications. Elemental S was as effective as gypsum in increasing alfalfa yields. Sulfur treatments significantly decreased the mortality of young alfalfa. The critical S level in mature alfalfa tissue ranged from .12 to .15% and the highest yields were obtained above 0.3%.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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