Relationship, requires input

Crop production requires input Synthetic fertilizer

The stored status is what a reviewer approved. The level below it is what the overlapping data support; the two are shown side by side and only a human moves the status.

Stored statusMechanism supportedEvidence level (latest analysis)not analysed yet

Mechanism, evidence, reviewer judgements

The edge as stored

Crop production requires input Synthetic fertilizer3 evidenceMechanism supported

Crop production depends on Synthetic fertilizer.

Mechanism

Yields depend on nitrogen, phosphorus and potassium supply, and synthetic fertilizer provides most of it on intensively farmed land. Manure, legume rotation and residue return substitute in part, and the response varies by soil and crop, so this is an agronomic mechanism rather than a fixed coefficient.

Evidence

documentFAO, Land and Waterfao.orgSoil nutrients, irrigation and freshwater use in agriculture.checked 2026-09-07
documentUSGS, Nitrogen (fixed), ammonia statistics and informationusgs.govAmmonia production from natural gas; fertilizer as the dominant end use; import reliance.checked 2026-09-07
metriccereal-yield

Status: mechanism_supported
Reviewer confidence: 0.90
Stated strength: 0.70
Lag: not stated
Version: curated_seed_v1
Reviewed: 2026-09-07

Confidence and strength are curated judgements recorded with the edge, not measured quantities.

Entity pages: Crop production, Synthetic fertilizer. Part of the mechanism Natural gas prices pass through ammonia into nitrogen fertilizer cost, crop yields and food supply.

Not computed

Statistical evidence

No analysis has been stored for this edge. The causal.analyze_all job runs monthly over every edge with a catalog metric linked to both entities; edges without a series on both ends are not analysed.

Not computed

Causal estimate

A causal estimate needs at least 20 overlapping periods and was not attempted for this edge yet.

What each rung means

Levels

Level 0: No association found
the overlapping data show no significant association.
Level 1: Correlation only
statistically associated in the overlapping periods; no direction, no mechanism.
Level 2: Predictive lead/lag
one series historically contains predictive information about the other.
Level 3: Mechanism supported
a documented physical, economic or institutional mechanism with cited evidence.
Level 4: Causally supported
a backdoor-adjusted estimate that survived refutation, on stated assumptions.
Level 5: Established relation
follows from engineering, accounting or scientific structure.

Every stored run, newest first

Analysis history

No runs stored.