Table 1 Comparison of observed (statistical data) and predicted (modelled) yields for maize and winter wheat, 1981–2007
Year | Maize | Winter wheat | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
obs. | pred. | e% | adjust | ae% | obs. | pred. | e% | adjust | ae% | |
1981 | 482.9 | 753.1 | 55.9 | 542.2 | 12.3 | 55.1 | 90.7 | 64.7 | 72.6 | 31.7 |
1982 | 491.6 | 650.7 | 32.4 | 468.5 | −4.7 | 64.5 | 78.7 | 22.0 | 62.9 | −2.4 |
1983 | 400.4 | 533.2 | 33.2 | 383.9 | −4.1 | 61.3 | 85.8 | 39.9 | 68.6 | 11.9 |
1984 | 413.2 | 642.9 | 55.6 | 462.9 | 12.0 | 63.3 | 96.5 | 52.5 | 77.2 | 22.0 |
1985 | 468.3 | 794.2 | 69.6 | 571.8 | 22.1 | 61.8 | 87.5 | 41.5 | 70.0 | 13.2 |
1986 | 460.5 | 715.7 | 55.4 | 515.3 | 11.9 | 78.3 | 82.0 | 4.7 | 65.6 | −16.3 |
1987 | 427.6 | 703.0 | 64.4 | 506.2 | 18.4 | 75.4 | 83.5 | 10.8 | 66.8 | −11.3 |
1988 | 458.4 | 528.8 | 15.4 | 380.8 | −16.9 | 71.5 | 73.8 | 3.2 | 59.0 | −17.4 |
1989 | 414.2 | 418.0 | 0.9 | 301.0 | −27.3 | 54.0 | 79.7 | 47.7 | 63.8 | 18.1 |
1990 | 379.8 | 516.2 | 35.9 | 371.6 | −2.2 | 71.9 | 79.0 | 9.9 | 63.2 | −12.1 |
1991 | 399.0 | 492.9 | 23.5 | 354.9 | −11.1 | 81.3 | 93.8 | 15.4 | 75.0 | −7.7 |
1992 | 367.8 | 382.0 | 3.9 | 275.1 | −25.2 | 75.3 | 78.0 | 3.6 | 62.4 | −17.1 |
1993 | 461.0 | 704.5 | 52.8 | 507.2 | 10.0 | 82.9 | 97.5 | 17.6 | 78.0 | −5.9 |
1994 | 429.1 | 638.6 | 48.8 | 459.8 | 7.2 | 81.5 | 96.1 | 17.9 | 76.9 | −5.6 |
1995 | 398.3 | 569.9 | 43.1 | 410.3 | 3.0 | 84.2 | 102.56 | 21.8 | 82.1 | −2.6 |
1996 | 424.7 | 639.3 | 50.5 | 460.3 | 8.4 | 82.4 | 83.4 | 1.3 | 66.7 | −19.0 |
1997 | 460.9 | 695.1 | 50.8 | 500.4 | 8.6 | 88.5 | 111.25 | 25.7 | 89.0 | 0.6 |
1998 | 454.5 | 655.9 | 44.3 | 472.3 | 3.9 | 82.0 | 102.68 | 25.3 | 82.2 | 0.2 |
1999 | 432.6 | 632.0 | 46.1 | 455.0 | 5.2 | 93.5 | 102.42 | 9.5 | 81.9 | −12.4 |
2000 | 496.3 | 582.3 | 17.3 | 419.3 | −15.5 | 87.7 | 98.5 | 12.2 | 84.8 | −3.4 |
2001 | 489.7 | 619.3 | 26.5 | 445.9 | −8.9 | 95.4 | 107.67 | 12.8 | 91.8 | −3.8 |
2002 | 470.7 | 650.1 | 38.1 | 468.1 | −0.6 | 76.4 | 117.61 | 54.0 | 99.3 | 30.0 |
2003 | 375.2 | 441.1 | 17.6 | 317.6 | −15.3 | 78.8 | 88.2 | 11.9 | 73,44 | −6.8 |
2004 | 480.6 | 722.4 | 50.3 | 520.2 | 8.2 | 89.9 | 125.68 | 39.7 | 103.8 | 15.4 |
2005 | 482.2 | 711.5 | 47.6 | 512.3 | 6.2 | 84.8 | 121.74 | 43.6 | 99.5 | 17.3 |
2006 | 421.5 | 581.0 | 37.9 | 418.3 | −0.7 | 84.3 | 102.66 | 21.8 | 93.0 | −1.6 |
2007 | 537.7 | 771.4 | 43.5 | 555.4 | 3.3 | 77.5 | 107.48 | 38.7 | 86.0 | 10.9 |
Mean | Mean | Mean | Mean | Mean | Mean | Mean | Mean | Mean | Mean | |
445.1 | 624.3 | 39.8 | 449.5 | 0.63 | 77.2 | 95.4 | 24.8 | 77.3 | 1.0 | |
Factor adjust | 0.72 | Factor adjust | 0.80 | |||||||
RMSE (dt/ha) | 42.9 | RMSE (dt/ha) | 9.6 | |||||||
% error | 9.6 | % error | 11.5 | |||||||
WIA | 0.89 | WIA | 0.74 | |||||||