SELENIUM ENRICHMENT OF CROPS THROUGH FOLIAR APPLICATIONS

Abstract

A field study was conducted, at two locations on Prince Edward Island, over a 5-yr period to determine the effects of foliar applications of sodium selenite on the Se concentration in barley (Hordeum vulgare L.) grain and in alfalfa (Medicago sativa L.) and timothy (Phleum pratense L.) foliage. Applications of 10–20 g Se ha−1 resulted in barley kernels and forage plant Se levels that would be adequate to prevent Se deficiency in most livestock. The highest rate of Se, at 80 g ha−1, resulted in plant Se concentrations of 706 μg kg−1 in timothy. The measured plant Se concentrations, to the same applications, varied from year to year but the responses to applied Se levels were generally in the same proportions. For similar application rates Se concentrations were lower in barley grain than in the forages. Tissue Se levels in the second cuts of alfalfa and timothy were lower than in the first cut. High levels of foliar-applied Se did not result in a carryover effect the following crop year. Annual foliar applications of Se would be required to raise the Se levels in crops into the sufficiency range for livestock feeds. Key words: Selenium content, foliar spray, cereals, forages, Podzol soils