Table 3.
The phosphate (P2O5) treatments applied with the corresponding amounts (kg ha−1) at Rothamsted and Woburn.
| Harvest yeara | P2O5 applied (kg ha−1) |
|---|---|
| 1962-1978b | control (0), +P (63) |
| 1968, 1974c | control (0), +P (125) |
| 1980d, e | control (0), P1 (25), P2 (25), P3 (75) |
| 1981 | control (0), P1 (50), P2 (0), P3 (50) |
| 1982 (Rothamsted) | control (0), P1 (0), P2, (50), P3 (50) |
| 1982 (Woburn) | control (0), P1 (50), P2 (50), P3 (100) |
| 1987c | control (0), P1 (25), P2 (25), P3 (75) |
a
P applied in the autumn, except in 1968 and 1974.
b
No P applied in 1969 (a fallow year or in the other fallow years: 1979, 1980, 1984).
c
For potato crops in 1968 and 1974 only was there a different + P treatment amount applied.
d
Residual P from1983 to 1986 and after 1984; no P fertiliser applied in these years.
e
From 1980 onwards the two P treatments (control, +P) were divided into four P treatments (control, P1, P2, P3). The control developed into a new control and P1 treatment, and the + P became P2 and P3.