Effects of the application of fertilisers and trace elements on the cobalt content of herbage cut for conservation

Publisher Website
Google Scholar
Abstract
The effects of the application of fertilisers, especially N and trace elements, on the content of Co in mixed grassland herbage and its main constituent species, have been studied. Data have been obtained from field experiments on three mineral soils and on a deep acid peat. The herbage was cut at the silage stage of growth three or four times a year for at least three successive years. Without added Co, N applications increased Co content in herbage on peat but reduced it on mineral soils mainly by eliminating clover which had a higher Co content than grasses. Applying 0.5 kg ha−1 Co as cobalt sulphate increased herbage Co content, the increase being greater on peat than on mineral soils. These increased levels were unaffected by N applications on mineral soils but were further increased by applied N on peat. The number of years during which the Co additions were effective in producing herbage containing at least 0.1 mg Co kg−1 dry matter varied on the different soils, ranging from barely three years on one mineral soil to over five years on peat. Without added Co the last cuts in October usually had the highest Co content and the first cuts in June the lowest. With added Co, the seasonal effects were more variable, but the Co content in the herbage frequently decreased from the first to the last cuts.