Open Access
Table II
Measured corn grain yielda in full plots or subplotsb and estimated weed-free full plot yield at the Farming Systems Project.
| Year | Systemc | Measured grain yield | Estimated yield | |||
|---|---|---|---|---|---|---|
| (Mg ha−1) | (Mg ha−1) | |||||
|
|
|
|||||
| Full plot | Subplot | Subplot | Full plot | |||
| weedy | weedy | weed-free | weed-free | |||
| 1997 | NT | 3.70 a | 2.70 a | 3.43 a | 4.14 a | |
| Org2 | 1.67 b | 2.10 a | 3.11 a | 2.56 b | ||
| Org3 | 2.79 a | 3.49 a | 3.74 a | 3.27 ab | ||
| Org4d | - | - | - | - | ||
| 1998 | NT | 1.81 a | fwe | fw | 2.11 b | |
| Org2 | 1.91 a | 1.50 a | 2.79 a | 4.71 a | ||
| Org3 | 2.31 a | 1.30 a | 1.92 a | 3.09 b | ||
| Org4 | 2.72 a | 1.93 a | 2.91 a | 3.12 b | ||
| 2001 | NT | 7.75 a | 8.10 a | 8.52 a | 8.85 a | |
| Org2 | 4.89 b | 5.08 c | 6.44 b | 5.88 b | ||
| Org3 | 4.82 b | 4.46 c | 5.74 b | 5.56 b | ||
| Org4 | 7.95 a | 6.66 b | 8.30 a | 8.54 a | ||
| 2002 | NT | 3.81 a | fw | fw | 3.91 a | |
| Org2 | 0.02 b | 0.20 a | 1.44 a | 0.72 b | ||
| Org3 | - | - | - | - | ||
| Org4 | 0.98 b | 0.91 a | 2.59 a | 3.34 a | ||
| 2004 | NT | 12.52 a | fw | fw | 12.52 a | |
| Org2 | 7.38 b | 8.18 a | 8.86 a | 7.38 b | ||
| Org3 | 8.08 b | 8.40 a | 8.59 a | 8.08 b | ||
| Org4 | 8.33 b | fw | fw | 8.33 b | ||
| 2005 | NT | 10.30 a | fw | fw | 10.31 a | |
| Org2 | 6.09 c | 7.18 a | 7.87 a | 6.88 c | ||
| Org3 | 8.89 b | 7.53 a | 8.97 a | 9.17 ab | ||
| Org4 | 8.72 b | fw | fw | 8.79 b | ||
a
Values followed by the same letter within a column and year are not significantly different (P < 0.05).
b
“Full plot” refers to plots 12 rows (9.1 m) by 111 m long from which yield was taken from the middle 4 rows. “Subplot” refers to a 4 row (3.0 m) by 6.1 m long area within a full plot from which yield was taken from the middle 2 rows.