Soil Fertilizer

In the dairy year

This is the ground the whole year stands on. Before spring you learn the knoll and the hollow. In spring you scout disease you cannot see from the cab. In autumn you rotate and choose tillage that will still be in the organic matter five years from now. In winter you decide whether a field goes into organic transition.

Last autumn’s soil is in this spring’s milk. That is not a slogan. The dairy reads the fields you named as feed.

The feel

Base FS25 fields are born equal and stay that way. Here each field, and each square once the map has layers, has its own nitrogen, phosphorus, potassium, pH, and organic matter. Drive across it. If the numbers change, that is not a glitch. That is your land.

Water finds the low ground. Organic matter follows. The hollow stays wet, richer, colder in spring, and more likely to leach and to harbour disease. The ridge sheds water and thins. You farm each corner on its own terms.

How it works

Five values are tracked independently for every field and persist in the save:

Nutrient	Role	What takes it down
Nitrogen (N)	Growth and leaf mass	Harvest, rain leaching, autumn
Phosphorus (P)	Root development and energy	Harvest
Potassium (K)	Water regulation and yield quality	Harvest, rain leaching
Organic matter	Structure and buffering	Builds slowly from manure, compost, and residue
pH	Unlocks the other nutrients	Rain acidifies it. Lime and ploughing raise it

Crops do not take the same amount. Potato and sugar beet are hungry for potassium. Soybean is hungry for nitrogen. Wheat, barley, oats, and rye are lighter feeders and better rotation crops.

The last three harvested crops are remembered. A legume followed by a non-legume gives a short spring nitrogen carry-over. The same crop two seasons running takes 15% extra N, P, and K at harvest. The Soil Report labels this as Rotation Bonus, Fatigue: Same Crop, or Rotation: OK.

Field health

Three pressure scores (0–100) sit on each field. Left alone they cut the litres in the hopper.

Pressure	How it grows	Treatment	Natural reset	Worst hit
Weed	Daily, worse without tillage	Herbicide	Any tillage or ploughing	−30%
Pest	Insects, peaks in summer	Insecticide	Harvest disperses them	−30%
Disease	Fungal, driven by rain	Fungicide	Three dry days start decay	−25%

Disease is not one number. Crops catch named diseases (wheat septoria, rust, fusarium; potato blight; soybean frogeye and white mould, and so on, around 40 in total). Scout (Shift+K) identifies what is on the field. Then you choose from a catalogue of 23 fungicides across seven chemistry families. Apply early, on-window, and not in the rain. Rotate families or they stop working.

Treatment panel (Shift+T) writes a prescription: which nutrients, lime, and protection that field needs right now.

What you can put on

Base-game liquid and solid fertiliser, manure, slurry, digestate, and lime all have real jobs. Shop tanks and bags add specialist products: UAN, anhydrous, MAP, DAP, potash, gypsum, compost, biosolids, chicken manure, pelletized manure, liquid lime, insecticide, and fungicide. Compost is the best organic-matter builder per litre. Lime does not feed the crop. Nothing else works properly without it.

Compaction and coverage

Vehicles of 8 tonnes or more add compaction once per game day. A subsoiler pass knocks 15% off. Natural decay is 0.5% per day. At full compaction you lose up to 15% yield even with full nutrients, and harvest takes up to 20% extra NPK. The HUD goes green under 20%, amber to 60%, red above that.

The sprayer tracks which cells you actually covered. The “field treated” notice waits for 70% coverage. A clip across one corner no longer counts.

What the weather does

Rain leaches nitrogen and potassium. Phosphorus barely moves. Autumn pulls nitrogen down. Spring gives a little back. Rain slowly acidifies pH. A field left unplanted for a week recovers a little on its own. Ploughing nudges pH toward neutral. Working stubble in releases a small NPK and organic-matter pulse. Deeper tillage releases more. Direct drill releases the least.

How you use it

Key (default)	What it does
Shift+K	Scout the field under you
Shift+T	Open the treatment panel
Shift+H	Drag HUD panels in Free Panel Layout
Shift+O (bind it once)	Full soil settings panel

The cab HUD is colour-coded: green is healthy, amber is getting low, red is already cutting yield. The yield row (for example Yield ~-18%) is the hit the combine will take, not a mood.

Esc opens a Soil & Fertilizer page with a farm-wide snapshot, a Farm Overview sorted by urgency, and a Treatment Plan. The native map overlay can show nitrogen, phosphorus, potassium, pH, organic matter, weed, pest, and disease.

On the Farm Tablet the Soil app lists owned fields, marks those that need fertiliser, and opens a detail panel for N, P, K, pH, organic matter, last crop, and days since harvest. Healthy pH is 6.0 to 7.5. Outside that, uptake drops even when the raw numbers look fine. Field Sentry appears when that bridge is present and lets an admin sleep a field or mark meadow.

Every one of these systems can be turned off in settings: fertility, nutrient cycles, seasonal effects, rain, ploughing bonus, residue, weed, pest, disease, rotation, and compaction. Off means that chapter goes quiet. You do not have to uninstall the zip.

The outs

Crop stress reads this ground for moisture and establishment. Dairy reads feed-field quality into herd health. The depot sells the products this soil asks for. Precision Farming is a stand-down, not a merge. If that pack is in the save, Soil goes quiet so the two models cannot fight.

What you need

This mod alone is a farm. The Soil Layer Installer is no longer required for a new save. Maps build their own per-pixel layers. Farm Tablet is the deep desk. Seasonal Crop Stress is the water chapter. Dairy Core is why the dirt matters in the barn. None of those are mandatory.