---
title: Should I use a pre-defined or custom fertilizer?
description: Pre-defined fertilizer are for clients who want an off-the-shelf product library. Custom fertilizer are for clients who don't have a 1:1 product mapping for their grower's fertilizers blends.
---

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# Should I use a pre-defined or custom fertilizer?

## Pre-defined fertilizer are for clients who want an off-the-shelf product library. Custom fertilizer are for clients who don't have a 1:1 product mapping for their grower's fertilizers blends.

**There are three type of fertilizer categories that might be applied: **

1. **Basic inorganics:** your traditional synthetic fertilizer (ex. Ammonium nitrate. 
     1. **EENF inorganics:** enhanced efficiency nitrogen fertilizers designed to reduce nitrogen losses to the environment and increase nitrogen availability to crops (ex. SuperU)
2. **Organics:** organic fertilizers or nutrients like manure, mulch, compost, etc.

Within both inorganics and organics, Measure API gives two options for describing the type of product: 

1. **Choosing a predefined product:** Choose a validated fertilizer product from an existing library where Regrow supplies a default nutrient ratios and a default liquid or dry form.
2. **Creating a custom product:** Create your own custom fertilizer product where all nutrient ratios are supplied by the client.

The following are available within Measure API and a guide for when to choose that object.

|   | **Predefined** | **Custom ** |
| --- | --- | --- |
| **Description** | Regrow-validated fertilizer products list with accompanying nutrient composition and liq/dry forms | Create your own custom fertilizer product where nutrient ratios and liquid densities (when applicable) are supplied by the client. |
| **When would I choose to use this type?** | - For clients who want to use an existing fertilizer library to increase ease of implementation. - For clients who do not require blends or customization. - For clients whose fertilizers and/or basic nutrient ratios match with Regrows. | - For clients who need the ability to customize the fertilizer products because there is no 1:1 mapping available for their products. |

#### Choosing a predefined fertilizer product

There is a list of fertilizer product names (ex. “Urea” or “Cow Manure”) validated and supported by the model that can be found in the API reference. 

All of these products correspond with validated nutrient compositions and liquid/dry formats defaulted by Regrow. The full list of products can be found under name in the API documentation.

Your example inorganic JSON may look something like this:

```
"Fertilizer": [  {    "name": "urea",    "date": "2024-05-01",    “amount”: 50,    "rate_unit": "pound",    "area_unit": "acre",    "application_method": "broadcast",    "additive": "urease_inhibitor",    }]
```

Your example organic JSON may look something like this:

```
"OrganicAmendment": [  {    "name": "manure_beef_solid",    "date": "2024-05-09",    “amount”: 250,    "rate_unit": "pound",    "area_unit": "acre",    "application_method": "broadcast",  }]
```

#### Creating a custom fertilizer

For clients who with to create a custom blend, first Measure API needs to know the product name, which will be "custom".

Next the input to the custom fertilizer requires percentages of the modeled fertilizer components for inorganic and organic respectively. It is not necessary to pass other ingredients that may have been included in the blend (ex. Herbicides, Water, etc) but that are not impacting outcomes.

The total percentage must be \> 0 and cannot exceed 100%

When the custom fertilizer is liquid/volume, then a liquid density must be included in the custom blend in order for Regrow to know how to convert your solution into dry units required by DNDC. 

Your inorganic example JSON may look something like this:

```
"Fertilizer": [  {    "name": "custom",    "date": "2024-05-01",    “amount”: 50,    "rate_unit": "gallon",    "area_unit": "acre",    "custom": {      "nitrate_percent": 30,      "ammonia_percent": 15,      "ammonium_percent": 0,      "urea_percent": 5,      "sulfate_perccent": 0,      "phosphate_percent": 0,      "liquid_density": 7.6,      "mass_liquid_density_unit": "pound",     }
```

Your inorganic example JSON may look something like this:

```
"OrganicAmendmentt": [  {    "name": "custom",    "date": "2024-05-01",    “amount”: 3,    "rate_unit": "ton",    "area_unit": "acre",    "application_method": "broadcast",    "custom": {      "nitrate_percent": 5,      "ammonium_percent": 0,      "urea_percent": 5,      "carbon_percent": 20,    }]
```

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