Selenium and Sulphur Concentrations in Primary Growths of Different Plant Communities

The factorised evaluated data of seven different grassland swards and two harvest dates of primary growths led to following results: Regarding the concentrations of selenium and sulphur, a selenium antagonist, and the N/S ratio, there were no significant plant community x harvest date, plant community x year, and harvest date x year interactions. The selenium concentrations, which never met the requirements of ruminants, were the highest in young herbage of a Bromion racemosi community reaching 49 µg kg-1 DM. The average of all swards and treatments was 33 µg kg-1 DM of selenium. Apparently, repeated application of selenate-bearing fertiliser is worthwhile in extensive grazing systems. Sulphur concentrations met the requirements of ruminants throughout. Because of the N/S ratio \u3c 15,7 the effect of additional sulphur supply is limited. Thus sulphur should not be fertilised, when selenium-bearing fertilisers are applied

Long-Term Effect of Levels of N-, P-, K-Supply on the Shannon-Index for Two Pastures Located in Central Germany

Intensive grassland production, including the use of mineral fertilisers, has degraded the botanical diversity of grassland communities seriously (Chapman, 2001). There is little information on optimal amounts of soil nutrient availability to maintain/regenerate species-rich grassland communities. This study in Central Germany aimed to quantify the long-term effect of different N-, P-, K-supply combinations on biodiversity, expressed in terms of the Shannon-Index (Sh-Id), of 2 pastures classified as Lolio-Cynosuretum