EFFECTS OF SELCOTE(R) ULTRA AND SODIUM SELENATE (LABORATORY VERSUS COMMERCIAL GRADE) ON SELENIUM CONCENTRATION IN FEED CROPS

Field studies were conducted at two locations in P.E.I., Canada on cer eals and forages on the effect of soil applications of Selcote(R) Ultr a and on a comparison of sodium selenate (laboratory versus commercial grade) on selenium (Se) concentration in plant tissue. Soil at both l ocations was sandy loam in texture and the soil pH ranged from 5.8 to 6.0. The data showed that 5 g Se ha(-1) added as Selcote(R) Ultra was adequate to raise the Se level in the first two cuts of forage tissue above the minimum required level of 100 mu g kg(-1). For cereals, 10 g Se was necessary to achieve the same level. The residual effect of 10 g Se ha(-1) from Selcote(R) Ultra added in the first year maintained plant Se at >100 mu g kg(-1) in the second year in the first cut of al falfa at one location and ryegrass at both locations. A comparison of selenate-Se (laboratory vs commercial grade) showed that both sources at similar levels of Se fertilization were equally effective in enrich ing barley gain with Se with no significant differences. Addition of 1 0 g Se ha(-1) rate was necessary to ensure adequate Se (>100 mu g kg(- 1)) concentration in the ensuing grain. Increasing rates of Se increas ed the Se levels in grain. Selenium concentrations were much higher in the barley boot stage vegetative tissue than in the grain. Results of this study showed that only 5 g Se ha(-1), as Selcote(R) Ultra, is ne eded to maintain adequate Se in forages. The laboratory and commercial ly available selenate-Se sources were equally effective in raising Se in barley.