EC — Energy Crops (Energiafgrøder)

Summary

Conversion to perennial energy crops (e.g. miscanthus, willow). Perennial crops have year-round root uptake, greatly reducing N leaching compared to annual crops. Restricted to fields with low livestock intensity.

Eligibility

PotV(i,"EC") = Countcy(i) × IniPotV(i) / 5   [if livestock(i) < 0.8]

Restricted to fields with livestock density below 0.8 DE/ha. Fields with high livestock intensity are excluded (the high organic N inputs from manure would undermine the benefit). Note: the sandy-soil restriction that previously existed was removed 2021-07-13.

N Effect

NEffM(i,"EC"):
  soil ≥ 5 (clay):  34 kg N/ha/yr
  soil < 5 (sandy): 51 kg N/ha/yr

(Source: catalog of N measures, page 116, checked 2021-06-29)

P Effect

None.

Cost

CostM(i,"EC"):
  soil ≥ 5 (clay):  prodcost(i) − 1,676  DKK/ha/yr
  soil < 5 (sandy): prodcost(i) + 599     DKK/ha/yr

On clay soils, energy crops can be profitable relative to conventional crops (negative net cost before any payments), because energy crop gross margins can exceed typical clay-soil arable margins. On sandy soils, they are more expensive.

Retention type

TR (Total retention)

Mutual exclusions

Member of mem(j).

Catalog source

DCA Rapport nr. 174 (Eriksen et al., 2020): Chapter "Flerårige energiafgrøder" (p. 138–151). Authors: Poul Erik Lærke, Uffe Jørgensen, Elly Møller Hansen et al.

N effect confirmed (Tabel 3 summary, p. 149): - Sandy soil: 51 kg N/ha/yr (confidence: , relative to corn-dominated rotation) - Clay soil: *34 kg N/ha/yr (confidence: , less data) - Wet marginal land: 0–100 kg N/ha/yr* (confidence: , highly uncertain; model doesn't include this category separately)

The model values (34/51 by soil type) match the catalog exactly.

What crops are assumed: Primarily willow (pil, Salix) as the reference crop. The economic analysis (Tabel 2, p. 148) is based on willow for biomass/district heating at 45 DKK/GJ. Results vary by yield (4 t dry matter/ha on sandy soil, up to 12 t/ha on clay soil). Miscanthus is also mentioned but willow is the primary economic reference.

Economics (from catalog, velfærdsøkonomiske, Tabel 3): - Sandy soil: 45 DKK/kg N (welfare), or 16 DKK/kg N for "wet sandy" soil - Clay soil: 51 DKK/kg N (welfare) - Wet marginal land: negative (−28 DKK/kg N) — energy crops can be more profitable than corn on wet marginal land

Budget economics from catalog summary: 13–35 DKK/kg N (sand), 40 DKK/kg N (clay). This is consistent with the model's CostM formula where clay-soil prodcost minus the energy crop revenue can be nearly zero or negative.

Data sources

• N effect values, cost structure: hard-coded in TargetEcon 2026.gms
• Opportunity cost (prodcost(i)): Cost_new_avg.inc + MarkAccess2.inc
• Livestock restriction (livestock(i) < 0.8): Dyretryk2.inc
• Soil type (SubSoil(i) for 34/51 split): SubSoil2.inc

Open questions

1. ✅ What crops: primarily willow. The 34/51 kg N/ha values are from the catalog's willow reference. Miscanthus would give similar or slightly higher effects.
2. The removal of the sandy-soil restriction (July 2021) — was this based on new empirical evidence or updated catalog values?

Related pages

• SA — set aside (related temporary conversion; both TR measures)
• FO — permanent conversion (higher N effect; includes subsidy offset)
• Retention types — EC uses TR (total retention)
• Cost concepts — EC cost can be negative on clay soils (energy crop margin exceeds prodcost)