# HALOWERK Eastern Land – Croatia Soil Nitrogen (0-5 cm)

> HALOWERK Eastern Land – Croatia Soil Nitrogen (0-5 cm) is a paid API for AI agents from ostland.halowerk.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-15).

Returns the mean SoilGrids total nitrogen content for the 0-5 cm soil layer at a given coordinate within Croatia, validated against Natural Earth boundaries.

## Facts

- Endpoint: POST https://ostland.halowerk.com/v1/hr-soil-nitrogen
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-eastern-land-croatia-soil-nitrogen-0-5-cm-963c61f3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_AiPeLY2Z9WH6yAAKRYfSe

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability halowerk-eastern-land-croatia-soil-nitrogen-0-5-cm-963c61f3 -d '<json body>'
```

Example prompt: What is the mean total nitrogen in the top 0-5 cm of soil at latitude 45.81 and longitude 15.98 in Croatia?

## When to prefer this

Use this endpoint when you need soil nitrogen data specifically for a point location within Croatia and want automatic boundary enforcement so out-of-country coordinates are rejected without incurring costs. Prefer this over general SoilGrids API calls when you need a pay-per-query micropayment model and Croatian-scoped validation built in.

## Known failure modes

- Coordinate outside Croatia boundary — rejected before payment with a validation error
- Coordinate within European bounding box but outside Croatia — boundary check fails and request is refused
- Latitude or longitude outside allowed European range (lat 34–72.5, lon -31.5–40.5) — schema validation error
- Network timeout or upstream SoilGrids data unavailability — service error returned
- Malformed or missing coordinate values — schema validation error

## How this service works

Mean SoilGrids total nitrogen for the 0-5 cm layer. The coordinate is validated against the Natural Earth boundary for Croatia; results outside it are rejected before payment.

## Output

A numeric value representing the mean SoilGrids total nitrogen for the 0-5 cm soil layer at the queried coordinate within Croatia, expressed in standard SoilGrids units (typically g/kg). Coordinates outside Croatian territory are rejected before processing.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "latitude": {
   "type": "number",
   "maximum": 72.5,
   "minimum": 34,
   "description": "WGS84 latitude inside the published European coverage."
  },
  "longitude": {
   "type": "number",
   "maximum": 40.5,
   "minimum": -31.5,
   "description": "WGS84 longitude inside the published European coverage."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-eastern-land-croatia-soil-nitrogen-0-5-cm-963c61f3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ostland.halowerk.com](https://www.zero.xyz/host/ostland.halowerk.com/llms.txt)