Selenium studies on peat

Abstract

Sodium selenite was incorporated with peat to a depth of 8 in. to raise the selenium concentration in selenium-deficient pasture by a method that would be safe for stock and effective for several years. The rates ranged from 4 to 128 oz of sodium selenite per acre mixed with superphosphate applied at 4 cwt per acre. The selenium concentration of pasture grown on plots receiving the above treatments showed good correlation with the rates applied. Levels dropped gradually during the first 15 months, but after that equilibrium had apparently been reached, as the selenium levels in clover for plots that received 32, 64, and 128 oz were maintained for another 2 years at 0.015, 0.023, and 0.034 ppm respectively. The different rates applied in this way can be considered safe for stock, as the herbage selenium level was at no stage toxic.