EFFECT OF VARIOUS SOURCES OF SULFUR ON YIELD AND SULFUR CONCENTRATION OF CEREALS AND FORAGES

Abstract

Field experiments were conducted at three locations in Prince Edward Island to determine the effects of various sources of S (Agri-Sul, gypsum, and Urea-Sul) on S concentration of tissue and yields of forages and cereals. Gypsum was effective in increasing the S concentration in plant tissues. Agri-Sul at 10–80 kg S∙ha−1 was generally ineffective in increasing the S concentration of forages and cereals. In the absence of added S (check treatments), the plant tissue S concentrations in alfalfa (Medicago sativa L.) and timothy (Phleum pratense L.) ranged from 0.18 to 0.39 and from 0.14 to 0.27%, respectively. In wheat (Triticum aestivum L.) and barley (Hordeum distichon L.), the S concentrations varied from 0.12 to 0.26 and from 0.13 to 0.20% in the boot stage tissue and grain, respectively, in the check treatments. In general, the S concentration was higher in the boot stage tissue than in the grain. Pea (Pisum sativum L.) seeds and vegetative material from the check treatments contained 0.19–0.24% and 0.17–0.36% S, respectively. Gypsum or Urea-Sul did not increase the yields of forages or cereals. In one instance Agri-Sul slightly increased the alfalfa yield (5–8.5%), but this was not associated with tissue S increases. Plant tissue S levels as low as 0.12–0.18% appeared to be adequate for barley, wheat, timothy, peas, and alfalfa. Key words: Sources of sulfur, tissue S, yields, cereals, forages