Table 1.
Summary of treatments in the long-term experiments.
| Woburn | Highfield | |||
|---|---|---|---|---|
| Location | 52° 1′ 12″ N, 0° 37′ 12″ W | 51° 80′ N, 00° 36′ W | ||
| Establishment | 1938–1942 | 1948 (1959 for bare fallow) | ||
| Previous history | > 62 years of arable | > 100 years of permanent grass | ||
| Soila | Sandy loam, 114–164 g clay kg−1 | Flinty silty clay loam, 233–335 g clay kg−1 | ||
| Structure | Three years of treatment crops followed by 2 years of test crops | Three years of treatment crops followed by 3 years of test crops | ||
| Treatments | Arable (no fallows) | Arable crop rotations with 1-year hay in rotation until 1975 | Arable | Arable crop rotations |
| Arable (with fallows) | Arable crop rotations with 1-year root crop until 1975 and 1-year fallow until 1995 | Bare fallow | Routinely ploughed and kept free of vegetation | |
| Lucerne/LC3b | Lucerne or sainfoin until 1975 after which 3-year grass-clover ley (LC3) | Grazed ley/LC3c | Changed from grazed ley to grass-clover ley (no inorganic nitrogen) from 1962 | |
| Grazed ley/LN3b | Grazed ley until 1975 after which 3-year grass with inorganic nitrogen (LN3) | Cut grass/LN3c | Changed from cut-grass ley to grass-ley with inorganic N additions from 1962 | |
|
Alternating/LC8b Alternating/LN8b |
Alternating cycles (arable, lucerne, or grazed ley) until 1975 after which a 10-year structure of either 8-year grass-clover ley (LC8) or 8-year grass with inorganic N (LN8) | Old grass | Old grass was undisturbed pasture and reseeded grass was broken up and re-sown to long-term grass; 3-year cycles (2 years sheep grazing, 1 years hay with aftermath grazing); grazing was discontinued in 1962 (old grass) and 1963 (reseeded grass) | |