Rotation Planning
Part of Crop Rotation
A rotation plan is the master document of a farm’s long-term strategy. It maps which crop family occupies each field in each year, balancing nutrient demands, disease pressure, soil structure, and market or subsistence needs across a cycle of three to eight years. Good rotation planning prevents the slow degradation that monoculture guarantees.
The Purpose of a Written Plan
Rotation planning fails most often not through poor design but through poor memory. A farmer who knows their system but does not write it down will drift — repeating a crop one year early under pressure, planting the wrong family in a disease-affected field, or losing track of when nitrogen was last added. The written plan is the correction mechanism.
A minimal rotation plan records:
- Field identity (name or number)
- Area in hectares or square metres
- Current and planned crop by year
- Amendments applied (manure, lime, compost) and dates
- Observed problems (pest damage, disease signs, waterlogging)
Understanding Plant Families
Rotation works primarily by separating crops of the same botanical family. Pathogens — fungal, bacterial, and nematode — are typically host-specific to one plant family. If the same family returns to a field before the pathogen population has declined, disease outbreaks compound year after year.
Major Crop Families and Their Rotation Requirements
| Family | Key Crops | Minimum Break | Key Disease Risk |
|---|---|---|---|
| Brassicaceae | Cabbage, turnip, swede, mustard, kale | 4 years | Clubroot, downy mildew |
| Solanaceae | Potato, tomato, pepper, aubergine | 4–5 years | Blight, sclerotinia |
| Leguminosae | Peas, beans, clover, vetch | 3 years | Foot rot, sclerotinia |
| Gramineae | Wheat, barley, rye, oats, maize | 2 years | Take-all, eyespot |
| Apiaceae | Carrot, parsnip, celery, parsley | 3 years | Carrot fly, cavity spot |
| Cucurbitaceae | Cucumber, squash, pumpkin, melon | 3 years | Powdery mildew, root rot |
| Alliaceae | Onion, leek, garlic, shallot | 4 years | White rot, leek rust |
White rot (Sclerotium cepivorum) in Alliaceae crops is essentially permanent. The fungal sclerotia survive in soil for 20+ years. Once a field is infected, do not grow any allium there again within your farming lifetime. This is not a 4-year problem — it is a permanent exclusion.
Designing a Rotation from Scratch
Begin with the crops you need most. For subsistence farming, these are typically: cereals (calories), legumes (protein and nitrogen), root vegetables (winter food and livestock), and brassicas (vitamins and winter greens).
Step 1: List Your Crops by Family
Cluster your planned crops into their families. Example for a 4-field holding:
- Field A: Brassicas (cabbage, turnip, kale)
- Field B: Cereals (wheat or rye)
- Field C: Legumes (field beans, peas)
- Field D: Root vegetables (carrots, beets, parsnips)
Step 2: Assign a Direction of Travel
Decide which way fields rotate each year. The classical direction is:
Legume → Cereal → Root/Brassica → Fallow or Ley
Legumes fix nitrogen. Cereals exploit it. Roots and brassicas clear weeds and improve structure. Fallow or grass ley rests and rebuilds.
Step 3: Expand to Match Your Disease Pressures
If brassica clubroot is a known problem, extend the brassica break to 5 years by adding an extra field in the legume or grass ley phase.
If potato cyst nematode has been detected, extend the potato-free period to 6 years and consider growing a trap crop (a nematode-susceptible variety that is not allowed to produce viable nematodes — specialist knowledge required).
Matching Crops to Soil Conditions
Not all fields have uniform soil. A rotation plan must match crop requirements to the physical reality of each field.
| Soil Type | Best Suited Crops | Avoid |
|---|---|---|
| Heavy clay | Wheat, beans, brassicas | Carrots (forking), parsnips (canker) |
| Light sandy | Carrots, parsnips, rye, potatoes | Winter wheat (leaching risk), beans |
| Waterlogged | Alder, willow (coppice) | Most crops until drainage improved |
| Stony | Brassicas, legumes, cereals | Root vegetables (deformation) |
| Acidic (pH <6.0) | Potatoes, rye, oats | Brassicas (clubroot risk), beets |
| Alkaline (pH >7.5) | Beets, brassicas, wheat | Potatoes (scab risk), blueberries |
Soil pH is the single most important soil parameter to know before planning a rotation. A simple pH test with litmus strips or a purchased soil test kit takes 10 minutes and prevents years of poor yields. Test each field separately — soil pH can vary dramatically across even a small holding.
Nitrogen Accounting in Rotation
Cereals and brassicas are heavy nitrogen consumers. Legumes are nitrogen donors. Roots and grass leys are neutral to moderate consumers. A functioning rotation plans nitrogen as a currency, tracking inputs (legumes, manure) and expenditures (cereals, brassicas) over the whole cycle.
Approximate Nitrogen Balance per Crop Phase
| Phase | N Input (kg/ha) | N Consumption (kg/ha) | Net Effect |
|---|---|---|---|
| Clover ley (1 year) | 150–250 (fixed) | 20–40 | Strong positive |
| Field beans | 100–180 (fixed) | 60–100 | Positive |
| Peas | 80–120 (fixed) | 80–120 | Neutral |
| Winter wheat | 0 | 180–220 | Negative |
| Potatoes | 0–30 (manure) | 150–200 | Negative |
| Brassicas | 0 | 120–180 | Negative |
| Root vegetables | 0 | 80–120 | Moderate negative |
| Grass/fallow | 0 | 20–40 | Near neutral |
A four-year rotation of beans → wheat → roots → wheat would show a nitrogen deficit by year three. The correction is to insert a legume or ley every second or third year, or to compensate with farmyard manure at 25–35 tonnes per hectare applied to the root crop phase.
Example Rotation Plans
Four-Field Subsistence Rotation
Suitable for a 2–4 hectare holding with mixed cereal, vegetable, and livestock needs.
| Year | Field 1 | Field 2 | Field 3 | Field 4 |
|---|---|---|---|---|
| 1 | Winter wheat | Field beans | Root crops | Brassicas |
| 2 | Field beans | Root crops | Brassicas | Winter wheat |
| 3 | Root crops | Brassicas | Winter wheat | Field beans |
| 4 | Brassicas | Winter wheat | Field beans | Root crops |
Manure application: Fields receiving root crops get 30–40 t/ha farmyard manure the preceding autumn.
Six-Year Rotation with Ley for Livestock Farms
| Year | Crop |
|---|---|
| 1 | Spring barley (nurse crop for ley establishment) |
| 2 | Grass/clover ley (cut for hay or grazed) |
| 3 | Grass/clover ley (grazed, building soil structure and N) |
| 4 | Winter wheat (exploits ley nitrogen) |
| 5 | Root crops (heavy manure applied; weed clean) |
| 6 | Winter beans or peas → repeat |
The grass/clover ley phase is the most powerful soil-building tool in rotation. Two years of mixed grass and white clover can fix 300–500 kg/ha of nitrogen total, restructure the top 30 cm of soil through root activity, and build organic matter by 0.3–0.5% — improvements that persist for several cereal years. If you have livestock to graze it, a ley phase should appear in every rotation.
Adjusting for Small Gardens
Garden-scale rotations work on the same principles but use beds instead of fields. A four-bed system with beds of 1.2 m x 3 m each can run a proper rotation:
- Bed A: Brassicas (cabbage, kale, broccoli)
- Bed B: Legumes (peas, beans, broad beans)
- Bed C: Roots (carrot, beet, parsnip, onion)
- Bed D: Potatoes or cereals (or squash)
Rotate clockwise each year. Mark each bed with a permanent stake labeled with its rotation position (R1, R2, R3, R4) to eliminate confusion. Record what was grown in each bed in a simple notebook.
Common Rotation Mistakes
| Mistake | Consequence | Correction |
|---|---|---|
| Repeating brassicas in same field after 2 years | Clubroot buildup; crop failure within 5 years | Hard 4-year minimum break |
| Growing cereals after cereals without break | Take-all root disease; yield loss 20–50% | Always break with legume or root crop |
| Neglecting to record amendments | Over- or under-liming; pH drift | Write every application in field journal |
| Planning only for one year ahead | Missing long-term disease cycles | Plan minimum 4 years in advance |
| Using the same soil for onions after leeks | White rot accumulation | Treat all Alliaceae as a single crop family |
Rotation Planning Summary
Effective rotation planning begins with mapping your crops by botanical family, then assigning each family to a field in a sequence that maximizes disease breaks and nitrogen balance. Write the plan down; record every deviation and amendment. Match crop choices to soil type and pH for each specific field. For subsistence farming, a four-year rotation of legume, cereal, root crop, and brassica — supplemented with farmyard manure in the root phase — provides the nutritional balance, soil improvement, and disease suppression that supports indefinite sustainable production.