The soils under permanent grassland are usually very rich in humus. The humus content in the top 10 cm is often more than 6%. Humus content and quantity can only be changed slightly in the long term in permanent grassland soils through different management and cultural measures. The humus content is primarily determined by the soil water balance. In particular, soils influenced by groundwater (gley, moor, fen) are very rich in humus. Regular and needs-based fertilization with carbon-rich, organic fertilizers (especially manure or compost) is necessary to maintain the humus content in the soil.
By increasing the amount of fertilizer applied annually, the humus content in the topsoil can be slightly increased. Humus can be enriched in overgrazed areas by reducing grazing intensity. In permanent grassland soils, the humus content is highest with medium management intensity (two to four uses per year, regular fertilization with manure or compost).
