Sod cutting and soil biota effects on seedling performance

摘要

Sod cutting (i.e. top soil removal) is a restoration management option for enhancing seedling estab-lishment and for lowering the nutrient concentration in eutrophicated soils of nutrient-poor species-richgrasslands. Removal of the upper soil changes not only abiotic soil properties but may also affect theresident soil community. We investigated the effects of sod cutting on the establishment and perfor-mance of two endangered plant species (Cirsium dissectum and Succisa pratensis) while simultaneouslymanipulating the interaction between seedlings and soil biota. In intact grassland and sod-cut areas attwo localities, seedlings were grown in plastic tubes. Half of the tubes had a filter that excluded roots butallowed entry of fungal hyphae and soil microorganisms. The other tubes were closed (i.e. no contactwith the surrounding soil). In a greenhouse experiment we studied the effect of soil solutions (with orwithout fungal tissue) from three grasslands and three sod-cut areas on seedling growth. Sod cutting hada positive net effect on seedling growth for S. pratensis. Access to (mycorrhizal) fungi and other soil biotaresulted in a negative impact on seedling growth of both plant species, both in grassland and sod-cutareas. The greenhouse experiment confirmed that the soil biota in these meadows reduced seedlinggrowth. Although sod cutting did not mitigate negative plant-soil feedback, it enhanced seedling growth,presumably by decreasing competition for light. Sod cutting is therefore very useful when seedlingestablishment needs to be stimulated.