Table D.2.
Irrigated scenario/crop combinations: New and former mean annual irrigation volumes; values for irrigation parameter PCDEPL to achieve a cumulated irrigation amount similar to FOCUS irrigation; field crops: new option 5 (over canopy, without surface run‐off; tall crops: new option 6 (under canopy, without surface run‐off); FLEACH = 0; RATEAP = 0.125
| Scenario | Crop | Irrigation Option | New mean annual irrigation volume (mm/a) with PCDEPL = 0.4 | Former mean annual irrigation volume (mm/a) (FOCUS, 2001) | PCDEPL resulting in irrigation volumes closest to FOCUS (2001) | Factor new/old irrigation volumes |
|---|---|---|---|---|---|---|
| R1 | Potatoes | 5 | 106 | 87 | 0.36 | 1.22 |
| Maize | 5 | 63 | 47 | 0.36 | 1.34 | |
| Sunflowers | 5 | 57 | 30 | 0.31 | 1.90 | |
| Sugar beets | 5 | 76 | 60 | 0.36 | 1.27 | |
| Vegetables, root | 5 | 133 | 111 | 0.35 | 1.20 | |
| Vegetables, leafy | 5 | 83 (48 + 35) | 131 | 0.54 (1st), 0.45 (2nd) | 0.63 | |
| Vegetables, bulb | 5 | 138 | 104 | 0.32 | 1.33 | |
| Legumes | 5 | 94 | 78 | 0.37 | 1.21 | |
| R3 | Potatoes | 5 | 276 | 276 | 0.40 | 1.00 |
| Sugar beets | 5 | 269 | 284 | 0.42 | 0.95 | |
| Field beans | 5 | 58 | 47 | 0.33 | 1.23 | |
| Vegetables, root | 5 | 42 | 39 | 0.36 | 1.09 | |
| Vegetables, leafy | 5 | 243 (50 + 194) | 305 | 0.38 (1st), 0.51 (2nd) | 0.80 | |
| Vegetables, bulb | 5 | 75 | 54 | 0.33 | 1.39 | |
| Legumes | 5 | 105 | 104a | 0.39 | 1.01 | |
| Vegetables, fruiting | 5 | 201 | 233 | 0.46 | 0.86 | |
| Maize | 5 | 219 | 258 | 0.47 | 0.85 | |
| Sunflower | 5 | 159 | 176 | 0.43 | 0.90 | |
| Soybeans | 5 | 267 | 282 | 0.44 | 0.95 | |
| Tobacco | 5 | 232 | 293 | 0.51 | 0.79 | |
| R4 | Maize | 5 | 382 | 398 | 0.44 | 0.96 |
| Field beans | 5 | 122 | 108 | 0.34 | 1.13 | |
| Root veg | 5 | 101 | 128 | 0.69 | 0.79 | |
| Vegetables, leafy | 5 | 398 (126 + 272) | 492 | 0.36 (1st), 0.65 (2nd) | 0.81 | |
| Bulb veg | 5 | 131 | 125 | 0.39 | 1.05 | |
| Legumes | 5 | 157 | 186 | 0.62 | 0.84 | |
| Fruit veg | 5 | 221 | 222 | 0.40 | 1.00 | |
| Pome/stone fruit | 6 | 318 | 317 | 0.40 | 1.00 | |
| Sunflower | 5 | 323 | 266 | 0.33 | 1.21 | |
| Soybeans | 5 | 484b | 159 | < 0.1 | 3.04 | |
| citrus | 6 | 110 | 113 | 0.41 | 0.97 |
a
Table 4.1.4‐2 in FOCUS (2001) gives 305 mm/a, but the actual mean annual irrigation volume in the corresponding weather file is 104 mm/a.
b
The high irrigation demand for soybean calculated in PRZM is most probably due to the combination of a relatively long cropping season with a relatively shallow (too shallow?) maximum root depth.