Incorporate leys into crop rotation

Overall effectiveness category Trade-off between benefit and harms
Number of studies: 1
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How is the evidence assessed?

Effectiveness

46%
Certainty

45%
Harms

36%

Calculating overall effectiveness category

Background information and definitions

This action involves converting arable land to grass or legume pasture (leys) for at least one growing season. We found evidence for one study examining different extents of grass pasture in leys.

Study locations

Key messages

One replicated study from Denmark showed that reducing the extent of grass pasture in leys reduced the undesirable uptake of nitrogen by grasses, therefore requiring lower rates of fertilizer for subsequent crops.

SOIL TYPE COVERED: sandy-loam.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated experiment from 1994 to 2006 on sandy-loam soil in Foulum, Denmark (Eriksen et al. 2008) found lower nitrogen uptake in 25% and 38% grassland leys than in a 75% grassland ley, therefore less fertilizer (average application 111 kg N/ha) was required to improve subsequent barley Hordeum vulgare crops, compared with after the 75% grassland ley (132 kg N/ha). Overall nitrogen uptake by perennial ryegrass was higher grown alone (126 kg N/ha), than in the perennial ryegrass-white clover Trifolium repens ley (109 kg N/ha) treatment. Four replicates of two crop rotations (in 576 m²plots) were established, including unfertilized ryegrass Lolium perenne-clover and fertilized (300 kg N/ha/y) ryegrass leys rotated with barley. Half of the barley plots were undersown with ryegrass. Each ley treatment was split into 25%, 38% and 75% grassland (remainder not specified). In 2002-2003, cattle slurry fertilizer was applied at three different rates: 0, 115 and 230 kg N/ha on 12 x 12 m plots. Up to 20 soil samples were taken periodically from each plot between 20-100 cm depth and soil carbon, nitrogen, nitrate and ammonium levels were measured.
Study and other actions tested
Referenced paper
Eriksen J., Askegaard M. & Søegaard K. (2008) Residual effect and nitrate leaching in grass-arable rotations: effect of grassland proportion, sward type and fertilizer history. Soil Use and Management, 24, 373-382.

Please cite as:

Key, G., Whitfield, M., Dicks, L.V., Sutherland, W.J. & Bardgett, R.D. (2020) Enhancing Soil Fertility. Pages 613-634 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.