# Farm & Garden Calc – Fertilizer Rate Calculator

> Farm & Garden Calc – Fertilizer Rate Calculator is a paid API for AI agents from agri-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Calculates the fertilizer product application rate and total quantity needed to hit a target N, P2O5, or K2O nutrient rate, and reports all nutrients supplied by that product rate.

## Facts

- Endpoint: GET https://agri-calc.x402tookit.com/fertilizer-rate?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/farm-garden-calc-fertilizer-rate-calculator-cf8d4fde
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fh_58gE9OS1KQgWflNcoE

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 farm-garden-calc-fertilizer-rate-calculator-cf8d4fde
```

Example prompt: How much urea (46-0-0) fertilizer do I need to apply per acre and in total across my 50-acre field to hit a nitrogen target of 120 lb/acre? Use imperial units.

## When to prefer this

Use this endpoint when you need to back-calculate a fertilizer product application rate from a desired nutrient delivery goal (N, P2O5, or K2O), rather than forward-calculating nutrients supplied from a known rate. Ideal for farm planning, purchasing decisions, and field-level nutrient management where the nutrient target is known but the product rate is not.

## Known failure modes

- Missing required query params (analysis, nutrient, targetRate) returns an error
- Invalid nutrient value (not n, p2o5, or k2o) returns an error
- Zero or negative targetRate may produce nonsensical results
- Invalid analysis string format (not N-P2O5-K2O) may cause parsing failure
- No area provided means totalProduct is null/omitted
- Network or payment failure returns no data

## How this service works

Fertilizer product rate and total needed to hit a target N, P2O5 or K2O rate, and all nutrients it supplies.

## Output

Returns the required fertilizer product rate per area unit (e.g. lb/acre or kg/ha), total product needed for the specified field size, and the amounts of N, P2O5, K2O, elemental P, and elemental K supplied at that rate. Also includes a text summary, units, and disclaimer.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "analysis",
      "nutrient",
      "targetRate"
     ],
     "properties": {
      "area": {
       "type": "number",
       "description": "Field size in acres (imperial) or hectares (metric), for the total product"
      },
      "units": {
       "type": "string",
       "description": "imperial (default: lb, acre) or metric (kg, ha)"
      },
      "analysis": {
       "type": "string",
       "description": "Product analysis N-P2O5-K2O percent, e.g. 46-0-0 or 18-46-0"
      },
      "nutrient": {
       "type": "string",
       "description": "Target nutrient: n, p2o5 or k2o"
      },
      "targetRate": {
       "type": "number",
       "description": "Target nutrient per area unit: lb/acre (imperial) or kg/ha (metric)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "area": {
       "type": [
        "null",
        "number"
       ]
      },
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "units": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "nSupplied": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
  
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/farm-garden-calc-fertilizer-rate-calculator-cf8d4fde/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agri-calc.x402tookit.com](https://www.zero.xyz/host/agri-calc.x402tookit.com/llms.txt)