The status of certain trace minerals and sulphur of some tropical grasses in Trinidad

One hundred and six grasses grown in plots 2.4 m x 1.2 m at the University Field Station, Valsayn, Trinidad, were cut at two 6-week periods of regrowt h, in the rainy season. They were all analysed for cobalt (Co), copper (Cu) , iron (Fe) molybdenum (Mo),and selenium (Se) and some were analysed for su lphur (S) contents. The ranges for Co, Cu, Fe, Mo, and Se mg kg-l dry matte r (DM) were 0.06-1.85, 2.2-11.9, 90-1473, 0.02-1.23, and 0.03-0.21, respect ively, and S ranged from 0.2 to 5.7 g kg(-1) DM. The percentages of grasses having concentrations of Co, Cu, Fe, Mo, and Se below 0.20, 10, 100, 0.50, and 0.10 mg kg(-1) DM were 8.5, 98.1, 0.9, 93.4, and 65.1, respectively. T he corresponding value of S below 2.0 g kg(-1) DM was 20.5. The results are discussed in the light of the requirements of grazing beef and dairy cattl e, sheep, and goats.