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Use a whole farm nutrient budget
The guidance on this page is for SFI pilot participants only. Please visit GOV.UK for the official Sustainable Farming Incentive scheme guidance.
Find out how land managers can reduce farm costs, increase crop yield and help the environment by balancing nutrient inputs and outputs across a whole farm.
If you’re completing this action as part of the Sustainable Farming Incentive pilot, how you do it is up to you.
The advice on this page can help you get better environmental and business benefits, but you do not have to follow it to get paid.
About whole farm nutrient budgeting
A whole farm nutrient budget compares the nutrients that enter the farm (inputs), with the nutrients that are leave the farm (outputs). To create a whole farm nutrient budget, you’ll need to record the nutrient value of each input and output. This will allow you to work out a farm nutrient balance.
The results can help you find out if you have a surplus or deficit of nutrients on the farm.
A surplus means there is a greater risk of nutrient losses. This can cause water or air pollution, or greenhouse gas emissions, as:
- ammonia or nitrous oxide gases are lost to the air
- nitrates leach into watercourses
- phosphates are carried into watercourses through field drains and by soil erosion and runoff
A deficit can indicate that crops and livestock do not get enough nutrients. This can:
- limit crop growth, which will reduce crop yield
- make livestock unhealthy, which can reduce productivity
Nutrient losses can still occur when you have a nutrient deficit, for example, through heavy rainfall.
Using nutrients efficiently
A whole farm nutrient budget will help you fix a nutrient surplus or deficit. You can:
- reduce nutrient losses to the environment
- match nutrients to livestock needs, to improve productivity
- match nutrients to crop needs, to improve yields
This will make sure your farm is sustainable in the long term.
Benefits of whole farm nutrient budgeting
A whole farm nutrient budget could help you to:
- save money on artificial fertiliser
- use home grown forage crops and improve farm self-sufficiency
- improve the quality and yield of crops
- improve livestock productivity
- reduce greenhouse gas emissions and help reduce the effects of climate change
- protect wildlife and sensitive habitats
How to use a whole farm nutrient budget
You should use a whole farm nutrient budget with a crop nutrient management plan and a livestock feed plan.
You must follow the farming rules for water. These require you to take steps to stop manure, fertiliser or soil getting into water bodies.
You must also have a nutrient plan if your farm is in a nitrogen vulnerable zone (NVZ). Use MAGIC to check if your land is in an NVZ.
You can complete a whole farm nutrient budget:
- annually
- for each cropping season
- for a livestock production cycle
The whole farm nutrient budget will only include the total inputs and outputs that ‘pass through’ the farm gate. Do not include cereals you grow to feed livestock on your farm.
This differs from a rotation budget, where you can measure inputs and outputs that pass through the field or block of land. A rotation budget would include manure you produce on your farm and spread onto the same field. Outputs in a rotation budget include those that leave a field, like straw used for bedding, and milling wheat sales.
Get help from a farm adviser
A farm adviser can help you calculate the nutrient value for each input and output to create the nutrient budget.
Use a Fertiliser Advisers Certification and Training Scheme (FACTS) qualified agronomist.
On farms with livestock, you can also use a registered feed adviser.
You’ll need to provide the adviser with accurate and detailed records of nutrient inputs and outputs.
Record inputs and outputs
Record the quantity and the nutrient content of inputs brought onto the farm, and of outputs taken off the farm. You should start with nitrogen (N), phosphorus (P), and potassium (K).
Your inputs might include:
- rainfall
- bought feed
- fertilisers
- organic manures, like slurry and digestate
- straw
- hay
- forage
- livestock
- any other input with a nutrient value brought onto the farm
If you grow legumes, you’ll need to estimate the nitrogen fixed (taken from the air) by legume crops. You should measure the legume crop yield, and the area grown.
Record the nutrient quantity, content and yield of the outputs that leave the farm, such as:
- grain
- straw
- hay
- silage
- organic manure, like slurry and digestate
- livestock
- crop
- meat
- milk
- any other output with a nutrient value that is sold, or moved from the farm
You should also record:
- crop areas
- livestock numbers
- application rates of fertilisers, and organic manures like slurry or digestate
Nutrient analysis
You can use nutrient analysis if your sewage, sludge or digestate suppliers do not provide standard nutrient content figures.
Analysis will give you a more accurate nutrient budget. This could include analysis of:
- forage, to assess the nutrients in livestock feed
- bought organic manure such as poultry manure or digestate
- straw, to measure the nutrient content of straw bought or sold off the farm
- rainwater, to measure nitrogen in rainfall
- grain, to measure nutrients in grain products and show nutrient deficiencies in the soil
Rain measurements
If you do not send rainwater for analysis, you can use standard figures from the Air Pollution Information System. Search using the grid reference of your farm and select the habitat type most suitable to your farm. The results will show the standard figure of nitrogen inputs from rain in kilograms per hectare.
Calculate the whole farm nutrient budget
When to calculate the nutrient budget
You can calculate a whole farm nutrient budget at any time of the year, but it’s best calculated at the end of the cropping season. This is when all records and measurements of nutrient inputs and outputs are available.
How to calculate the total inputs and outputs
The adviser will use the records you provide to calculate the yearly total of N, P and K in each input and each output.
They’ll then use these figures to calculate a total of N, P and K for all inputs and outputs. They will use equivalent units like kilograms or tonnes for the calculations.
The figures should be set out in a table. This will help you review the nutrient budget with the adviser.
Farms with livestock
You’ll have more inputs and outputs to consider if you have livestock. You’re more likely to have a nutrient surplus if you:
- produce a large volume of organic manure with a high nutrient content to spread over a small area
- bring large volumes of organic manure with high nutrient content on to the farm
Create a whole farm manure management plan alongside a whole farm nutrient budget. This will help you make better use of the manure produced to match the needs of your crop. You’ll identify areas unsuitable for spreading due to risk to water quality.
You can use the feed plan from Tried & Tested to match feed to nutrient requirements of sheep and cattle. A balanced diet will make sure animals stay healthy and productive.
Organic farms
A whole farm nutrient deficit is more common on organic farms. It’s often difficult to correct as you can not apply artificial fertiliser.
A whole farm nutrient budget can help you achieve a nutrient balance across a rotation.
Identify changes you can make
Review the nutrient budget with the adviser to identify and plan where you can improve the balance of nutrient inputs and outputs. You can test different scenarios across the whole farm to help you correct a nutrient surplus or deficit.
You could:
- reduce bought feed and replace with home grown forage
- recover nutrients from cover crops and green manures and save on fertiliser costs
- replace fertilisers with nitrogen fixing crops like legumes and clover in pasture
- replace fertilisers with organic manure
Tools to help you manage farm nutrients
In addition to help from an adviser, you can use free tools to manage the nutrients on your farm.
You can use the PLANET farmgate budgeting module to help you record inputs and outputs.
Organic and non-organic farms can follow the Institute of Organic Training and Advice guide to nutrient budgeting.
Use the Agriculture and Horticulture Development Board’s nutrient management guide. This can guide you through crop nutrient management on a field basis. It will tell you the ideal amount of nutrients each crop requires. The nutrient management guide includes standard figures of nutrients in organic manures and crop outputs.
Soil analysis
Test your soil to show any areas that have high or low levels of nutrients, or any changes in levels. This will help you match nutrients to the crop requirements.
Take basic soil samples every 3 to 5 years. You should test for:
- P, K and magnesium (Mg)
- pH level
- soil organic matter
Test soil at the same stage in the rotation, at the same time of year.
Take soil samples when nutrient levels are likely to be lowest. This is usually between September and March after you harvest the previous crop. The soil samples will show the residual nutrients in the soil that will be used by the next crop.
Good soil health will help crops use nutrients effectively. Manage soil to prevent soil compaction and reduce runoff, which can limit crop growth.
Sample for nitrogen
Soil mineral nitrogen (SMN) measurements will help you assess the soil nitrogen available to the growing crop. This will show you the best nitrogen application rates for the crop. You should measure SMN if you use large amounts of organic manure on your fields.
To measure SMN, you’ll need to take soil samples and send them to a lab for analysis. You should take samples at different soil depths.
Alternatively, use a field assessment and crop history to estimate the nitrogen content in the soil.
