NVZ Compliance with Herdwatch Nitrates Calculator

In the UK, farms located within Nitrate Vulnerable Zones (NVZs) are required to adhere to strict regulations regarding nitrogen per hectare. These limits are in place to protect water quality from agricultural nitrate pollution. The Herdwatch Nitrates Calculator helps farmers stay on track by allowing them to adjust factors such as cattle numbers and import/export slurry to instantly see how these decisions impact your final KG/N/HA figure and plan accordingly. By visualising your farm’s nutrient application data and comparing it to the legal limits, you can make informed decisions to stay compliant with NVZ regulations. In addition, the decision support tool helps farmers plan their nutrient management with precision, ensuring their fertiliser use is both cost-effective and environmentally responsible.

The Nitrates and Phosphates Decision Support Tool offers farmers real-time data and actionable insights on nutrient management. Using the interactive digital map, farmers can visualise their fields and manage nutrient applications with precision, ensuring they stay within regulatory limits for NVZs.

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What are nitrates?

Nitrates are chemical compounds that are essential for plant growth, acting as a crucial source of nitrogen. In agriculture, they often come from fertilisers and animal manure. However, excessive use or mismanagement of these compounds can lead to environmental issues, such as water pollution and biodiversity loss.

Legal requirements / rules

In the UK, You can apply up to 170kg per hectare of nitrogen in livestock manure (including manure deposited directly by livestock and spreading) on your holding in each calendar year. This limit is the loading limit and applies as an average across your holding. It’s separate from the field limit of 250kg per hectare from organic manures.

You must not use more than 250kg of total nitrogen from all organic manures spread in any 12 month period on any single hectare of your land. This limit (the field limit) doesn’t include livestock manures deposited by grazing animals.

Farmers are required to keep detailed records of their nitrogen use, which includes the following:

Livestock numbers: Accurate records of livestock are vital as they determine the nitrogen output from animal waste.
Fertiliser use: Farmers must record the types and amounts of fertilisers applied to their land.
Slurry management: The storage, application, and export of slurry must be tracked to ensure compliance with nitrate regulations.
Crop management: Records of crop types and their nitrogen requirements are also necessary.

Grassland derogation

If at least 80% of your holding is grassland, you can apply for grassland derogation to use a higher limit of up to 250kg of nitrogen per hectare, if the nitrogen comes from grazing livestock manure, i.e. sheep or cattle.

You can apply for 2025 grassland derogation, find out more information on your region:

In England, applications for 2025 derogation close 31^st December 2024.

In Scotland, applications for 2025 derogation closed 30^th April 2024.

In Northern Ireland, applications for 2025 derogation closed March 1^st 2024.

Planning your nitrogen usage:

You must plan all your applications of nitrogen on each crop in each field (including grass). This is your fertilisation plan, which you must keep as part of your farm records.

Your plan must show you’ve taken the following steps before you apply nitrogen for the first time in a field where you’re going to plant a crop or have planted a crop:

Calculate the amount of nitrogen in the soil that’s likely to be available for the crop to use during the growing season.
Calculate the optimum amount of nitrogen that should be applied to the crop, taking into account the amount of nitrogen already available in the soil.
Calculate the amount of nitrogen from any planned applications of organic manure that’s likely to be available to the crop in the growing season in which you spread it.
Calculate the amount of manufactured nitrogen fertiliser you need.

You must also carry out steps 1 and 2 before you apply any nitrogen fertiliser or manure for the first time.

Using the Nitrates Calculator on Mobile:

Access the home screen: Open the Herdwatch app and navigate to the home screen.
Select ‘Management’: Click on the ‘Management’ section to access various management tools.
Choose ‘Nitrates Calculator’: Select the Nitrates Calculator from the menu.
Input relevant data: Choose options that apply to your farm, then click ‘Next’.
View results: The calculator will provide an estimate of your nitrates in app, allowing you to assess your current position.

Using the Nitrates Calculator on Big Screen (Web App):

Visit the home screen: Log into the Herdwatch web app on your computer and access the home screen.
Select ‘Management’: Like the mobile app, click on the ‘Management’ section.
Choose ‘Nitrates Calculator’: Select the Nitrates Calculator feature.
Input your parameters: Depending on whether you run a beef/suckler or dairy operation, input the relevant parameters.
Stock numbers will be calculated on a monthly basis based on your herd in app over the year, with current stock projected to year end
Edit or fill in data: You can adjust any existing data to reflect your current operations accurately.
Save – Once you have calculated your nitrates, you can save a draft of your calculator at any time for reference at a later date, through ‘view drafts’
Download Your Results: You can select the download option to save your results as a PDF for your records

Adding points of interest to your farm maps for NVZ compliance

Simply add a point on a map to keep account of field records. This feature enhances mapping for efficient farm management by visually documenting and accessing important locations easily which is also crucial for NVZ compliance.

To add points of interest to the farm maps:

Go to Field Job/Note
Select “Add Point/Add Line/Add Area” and pick the type from the list
Enter details and select ‘Next’
You will then see the map of your farm tap where you want to start the point of interest and tap again to end. Select ‘Finish’ and ‘Save’
All types are colour-coded once on the map some examples are:
1. Well/Borehole – Dark Blue
2. Field Heap – Brown
3. Water Drinker – Pink
4. Feeder – Purple

Benefits of using the Nitrates Calculator

The Nitrates Calculator is designed to enhance farmers’ understanding of their nitrogen outputs, offering several advantages:

Proactive management: By allowing farmers to adjust cattle numbers and import/export slurry, the calculator enables proactive management of nitrogen levels. This flexibility can help farmers remain within legal limits and plan for the upcoming year.
Record keeping: The ability to save results as a PDF simplifies record-keeping and allows you to keep track of the nitrates levels on your farm.
Tailored insights: Whether using a mobile device or a desktop, farmers can receive tailored insights based on their specific operations, facilitating informed decision-making.
Enhanced compliance: Regular use of the Nitrates Calculator can help ensure that farmers remain compliant with nitrate regulations.

The nitrates situation in UK agriculture presents both challenges and opportunities for farmers. By understanding the importance of nitrates and adhering to legal requirements, farmers can play a crucial role in protecting the environment while maintaining productivity.

The Herdwatch Nitrates Calculator is a powerful tool that can help farmers manage their nitrogen levels effectively, ensuring compliance and promoting sustainable agricultural practices.

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