Individual study: Plant diversity and herb cover was significantly higher in grassland with organic fertiliser than mineral fertiliser applications in the uplands of Wales
Jones D. & Haggar R.J. (1993) Impact on nitrogen and organic manures on yield and botanical diversity of a grassland field margin. Forward with grass into Europe: British Grassland Society Winter Meeting, Great Malvern, Worcestershire, 16-17 November 1992, 135.
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Use organic rather than mineral fertilizers
A replicated, controlled, randomized study from 1988 to 1991 of an upland permanent pasture at Bronydd Mawr Research Centre, Powys, UK (Jones & Haggar 1993) found that plant diversity and herb cover was significantly higher in grassland with organic fertilizer than mineral fertilizer applications. Plots with farmyard manure and slurry had significantly higher species diversity (both 28% of species) than high (300 kg N/ha, 13% herbs) and low (100 kg N/ha, 18%) mineral applications and similar to unfertilized plots (31%). Nitrogen fertilizers resulted in a significant decrease in species diversity in the hedge bottom; in 1991, only 11 hedgerow species were present on mineral N treatments, 50% less than organic and control treatments. Herb cover was also lower in high (16-21%) and low (18-23%) N applications compared to farmyard manure (28-34%), slurry (27-28%) and the control (33-34%). Vegetation production was significantly higher with high N applications (1697 g dry matter/m²) than other treatments (low N: 1413, farmyard manure: 1343, slurry: 1175, control 973 g dry matter/m²). Sheep grazed grassland plots (7 x 4 m) extending into the hedge bottom were established. A randomized block design with three replicates was set up with the five treatments. Vegetation was sampled monthly within plots between April-November 1988-1991 and hedge bottoms were sampled in spring, summer and autumn each year.