Effects of fertilisers on plant species composition and conservation interest of UK grassland

Maintain species-rich, semi-natural grassland

A 1994 review (Smith 1994) describes the results of a controlled trial in 1990-1992 on a species-rich upland meadow with a plant community characterized by sweet vernal grass Anthoxanthum odoratum and wood cranesbill Geranium sylvaticum (MG3 under the UK National Vegetation Classification) in the Pennines, northern England. The highest species richness (on average 17 species per 25 x 25 cm quadrat) was produced by a combination of a mid-July hay cut, spring and autumn grazing and no fertilizer. The lowest species richness was produced by no grazing, application of fertilizer and either a September (on average 10 species/quadrat) or June (11 species/quadrat) hay cut. Autumn-only grazing produced a vegetation layer with an intermediate species-richness (13-16 species/quadrat). Combinations of the following treatments were compared: cutting in mid-June, mid-July or early September; spring-sheep and autumn-cattle grazing, autumn-cattle grazing or no grazing; nitrogen, phosphorous, potassium (NPK) fertilizer (400 kg/ha) or no fertilizer. The number of replicates is not stated.