| In agricultural systems with low S inputs, crops rely on the release of S from organic forms in the soil. In the Askov long-term experiments, started in 1894 on both sandy and loamy soils, was investigated the soil S status following long-term application of animal manure and mineral fertilizers in the growing season of 1995. In a field trial with oil-seed rape (Brassica napus, L.) soil analysis, leaf tissue analysis, yield and S-removal in plant material was used to characterize differences in availability of soil S. One half of all plots had 63 kg S/ha as gypsum applied. Fertilization with animal manure or NPK fertilizer increased the content of soil organic C compared with unfertilized plots. This increase was followed by a similar build-up of organic... |
