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Providing evidence to improve practice

Individual study: Plant species richness was significantly higher on organic farms than conventional farms in the Netherlands

Published source details

Manhoudt A.G.E., Visser A.J. & de Snoo G.R. (2007) Management regimes and farming practices enhancing plant species richness on ditch banks. Agriculture, Ecosystems & Environment, 119, 353-358


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Manage ditches to benefit wildlife Farmland Conservation

A replicated site comparison study from 1999 to 2004 in the Netherlands (Manhoudt et al. 2007) found that ditch management affected plant diversity. Diversity was significantly higher on farms with ecologically managed ditches (mown once in September, cuttings removed to reduce nutrient input) buffered with ≥ 3 m-wide field margin strips (36-65 plant species/400 m2) and organic farms (converted to organic less than 5 years ago: 32 plant species/400 m2, converted more than 5 years ago: 36-52 plant species/400 m2) than conventional farms (26-34 species/400 m2). On ecologically managed farms plant diversity increased significantly over six years (up to 27%), there was a small shift to less common plant species and a decrease in the number of nitrogen rich species and Ellenberg nitrogen-values. There tended to be more nitrogen poor species on ecologically-managed and organic farms compared to conventional farms. Four ecologically managed farms, 18 conventional and 20 organic arable farms were studied. Cutting date varied on conventional and organic farms, but cuttings were never removed, ditches on both farm-types did not have buffer field margin strips. On ecologically managed farms, plant species surveys of 100 m of ditch bank spread over the whole farm were undertaken once a year 1999-2004. On organic (in 2001) and conventional (2003) farms, plant species presence was recorded on 10 x 25 m of ditch bank along a transect (May-June).

Provide buffer strips alongside water courses (rivers and streams) Farmland Conservation

A replicated site comparison study from 1999 to 2004 in the Netherlands (Manhoudt et al. 2007) found that ditch bank plant diversity was significantly higher on farms with ecologically-managed ditches with ≥ 3 m-wide field margin buffer strips (36-65 plant species/400 m2) compared to conventionally managed farms without buffer margins or ecological management (26-34 plant species/400 m2). The number of plant species on ecologically-managed ditch banks with buffer strips was also higher than ditch banks without buffer strips or ecological management on organic farms (32-52 plant species/400 m2). Ecologically managed strips were cut once in September and the cuttings removed to reduce nutrient input. Cutting date varied on conventional and organic farms, but cuttings were never removed. Four ecologically managed farms, 18 conventional and 20 organic arable farms were studied. On ecologically managed farms, plant species surveys of 100 m of ditch bank spread over the whole farm were undertaken once a year from 1999 to 2004. On organic (in 2001) and conventional (2003) farms, plant species presence was recorded on 10 x 25 m of ditch bank along a transect (May-June).