IC — Intermediate Crops (Mellemafgrøder)¶

Summary¶

Sowing of a short-cycle intermediate crop between a winter harvest and autumn sowing of the next winter crop. Reduces the period of bare soil, capturing residual N.

Eligibility¶

PotV(i,"IC") = 0.25 × Sum(cy, wc(i,cy)) / 5 Only 25% of the winter-cropped area is eligible — reflecting that IC is only feasible in a portion of the rotation and requires specific crop sequences.

N Effect¶

NEffM(i,"IC") = 14 kg N/ha/yr (flat, confirmed 2021-06-29)

P Effect¶

None.

Cost¶

CostM(i,"IC") = 325 DKK/ha/yr

Retention type¶

TR

Mutual exclusions¶

Member of mem(j), lm(j).

Catalog source¶

DCA Rapport nr. 174 (Eriksen et al., 2020): Chapter "Mellemafgrøder" (p. 74–86). Authors: Ingrid K. Thomsen, Elly Møller Hansen, Birte Boelt et al.

N effect from catalog: 8–19 kg N/ha/yr (confidence: ). The model uses *14 kg N/ha as a fixed average, which falls near the midpoint of the catalog range.

Mechanism: Intermediate crops (typically cruciferous species like oil radish, yellow mustard, or ryegrass) are sown immediately after harvest of a previous crop (usually grain) and before sowing of the following winter crop. The crop must be established by 20 July and destroyed no earlier than 20 September (per regulations). The short growing window limits the N uptake potential compared to catch crops.

Overlap: Intermediate crops cannot be combined with catch crops or other measures involving autumn plantings. When combined with drain measures (IBZ, wetlands), the intermediate crop reduces the drain N load, partially displacing the drain measure's effect.

Cost from catalog: 9–30 DKK/kg N (budget), 12–39 DKK/kg N (welfare). The model's 325 DKK/ha implementation cost is consistent with catalog ranges.

Confidence: *** (high — well-established evidence base)

Data sources¶

N effect, cost, eligibility criteria: hard-coded in TargetEcon 2026.gms
Crop rotation data (wc(i,cy)): MarkAccess2.inc

Notes¶

Low N effect and low cost. Cost-effectiveness competitive in high-retention catchments where large-effect measures' benefits are discounted.
The 25% eligible area restriction reflects that IC requires a specific crop sequence window — not all winter-cropped fields have the right rotation timing.

EW — early sowing; similar low-cost N-only measure; 30% winter-crop eligibility
CCS / CCW — catch crops (alternative N-only measures in lm set)
Retention types — IC uses TR (total retention)
Cost concepts — fixed cost only (325 DKK/ha/yr)