Do farm management practices alter below-ground biodiversity and ecosystem function? Implications for sustainable land management

Maintain upland heath/moorland

A 2006 review of UK studies (Stockdale et al. 2006) on the impact of farm management practices on below-ground biodiversity and ecosystem function reported four studies which found positive impacts of increased grazing on soil bacteria (Yeates et al. 1997), earthworms (Lumbricidae) (Muldowney et al. 2003) and on mites (Acari), springtails (Collembola) and nematodes (Nematoda) (Bardgett et al. 1993, 1997) in upland habitats.

Additional references:

Bardgett R.D., Whittaker J.B. & Frankland J.C. (1993) The diet and food preferences of Onychiurus procampatus (Collembola) from upland grassland soils. Biology and Fertility of Soils, 16, 296-298.

Bardgett R.D., Leemans D.K., Cook R., & Hobbs P.J. (1997) Seasonality of the soil biota of grazed and ungrazed hill grasslands. Soil Biology & Biochemistry, 29, 1285-1294.

Yeates G. W., Bardgett R. D., Cook R., Hobbs P. J., Bowling P. J. & Potter J. F. (1997) Faunal and microbial diversity in three Welsh grassland soils under conventional and organic management regimes. Journal of Applied Ecology, 34, 453-470.

Muldowney J., Curry J.P., O’Keeffe J. & Schmidt O. (2003) Relationships between earthworm populations, grassland management and badger densities in County Kilkenny, Ireland. Pedobiologia, 47, 913-919

Reduce grazing intensity on grassland (including seasonal removal of livestock)

A 2006 review of UK studies (Stockdale et al. 2006) on the impact of farm management practices on below-ground biodiversity and ecosystem function indicates that the impact of reduced grazing intensity on the diversity of soil organisms is likely to vary among taxa. Three studies found that increased grazing pressure had a negative impact, in terms of species richness or abundance, on ground beetles (Carabidae) (Ni Bhriain et al. 2002), spiders (Araneae) (Macaulay Institute 2006), and nematodes (Nematoda) in lowland habitats (Mulder et al. 2003). One study found that grazing pressure had no impact on the profile of soil fungal communities (Clegg 2006).

Additional references:

Ni Bhriain B., Skeffington M.S. & Gormally M. (2002). Conservation implications of land use practices on the plant and carabid beetle communities of two turloughs in Co. Galway, Ireland. Biological Conservation, 105, 81-92.

Mulder C., De Zwart D., Van Wijnen H. J., Schouten A.J. & Breure A.M. (2003) Observational and simulated evidence of ecological shifts within the soil nematode community of agroecosystems under conventional and organic farming. Functional Ecology, 17, 516-525.

Clegg C.D. (2006) Impact of cattle grazing and inorganic fertiliser additions to managed grasslands on the microbial community composition of soils. Applied Soil Ecology, 31, 73-82.

Macaulay Institute (2006) Grazing and upland birds. Available at www.macaulay.ac.uk/projects/projectdetails.php?302797 Accessed 13 March 2006.

Reduce tillage

A 2006 review (Stockdale et al. 2006) of the impact of farm management practices on below-ground biodiversity and ecosystem function found tillage had negative effects on beetles (Coleoptera), springtails (Collembola), mites (Acari), spiders (Araneae), and earthworms (Lumbricidae). The review looked at studies worldwide but here we focus on European studies. One review (Wardle 1995) (location not provided) concluded that tillage tends to reduce large soil organisms (beetles, spiders and earthworms) more than the smallest ones (bacteria, fungi), and that intermediate-sized groups (nematodes (Nematoda), mites and potworms (Enchytraeidae)) can show small population increases. Two studies (one from Sweden, one review) demonstrated the direct negative effects of tillage on mites, springtails, and beetles (Andren & Lagerlöf 1980, Wardle 1995); and a further study showed that compaction during tilling can reduce the number of earthworms and microarthropods (Aritajat et al. 1977; location not given). One study from Denmark showed that tillage reduced the springtail population to about 1/3 of the pre-tillage level one week after cultivation (Petersen 2002). Two studies (one study from Switzerland) noted differences in the species composition of arbuscular mycorrhizal fungi, earthworms and nematodes (Nematoda) between tillage and no-till systems (Wardle 1995, Jansa et al. 2003). Two studies (one study from Germany) investigated the impact of tillage on the balance between bacteria and fungi, with mixed results (Wardle 1995, Ahl et al. 1998). One study from the UK found that invertebrate food resources for birds increased in no-till compared to conventionally tilled systems (Tucker 1992).

Additional references:

Aritajat U., Madge D.S., & Gooderham P.T. (1977) Effects of compaction of agricultural soils on soil fauna .1. Field Investigations. Pedobiologia, 17, 262-282.

Andren O. & Lagerlöf J. (1980) The abundance of soil animals (microarthropoda, enchytraeids, nematoda) in a crop rotation dominated by ley and in a rotation with varied crops. Pages 274-279 in: D. L. Dindal (ed.) Soil Biology is related to land-use practices. Environmental Protection Agency, Washington.

Tucker G. M. (1992) Effects of agricultural practices on food use by invertebrate feeding birds in winter. Journal of Applied Ecology, 29, 779-790.

Wardle D. A. (1995) Impacts of disturbance on detritus food webs in agro-ecosystems of contrasting tillage and weed management practices. Advances in Ecological Research, 26, 105-185.

Ahl C., Joergensen R.G., Kandeler E., Meyer B., & Woehler V. (1998) Microbial biomass and activity in silt and sand loams after long-term shallow tillage in central Germany. Soil and Tillage Research, 49, 93-104.

Jansa J., Mozafar A., Kuhn G., Anken T., Ruh R., Sanders I.R. & Frossard E. (2003) Soil tillage affects the community structure of mycorrhizal fungi in maize roots. Ecological Applications, 13, 1164-1176.