Keeping the following records up-to-date every year is a requirement under ‘Nitrate Vulnerable Zone’ (NVZ) regulations.
1. Evidence of your ‘Livestock Manure Nitrogen Farm Limit’ (i.e., stocking rate) calculation
You must show that the total nitrogen produced by the livestock on your farm does not exceed the ‘Farm Limit’ of 170kg N/ha/yr for any part of your farm that is in an NVZ.
This calculation will change at least annually, depending on the precise details of your cattle population. The calculation must be completed using the ‘standard values tables’ supplied by DEFRA. These tables are quite ‘particular’: e.g., there are 14 different categories for cattle, depending on age, weight, sex, castration status, purpose (breeding, non-breeding, milking), and milk yield, with each category having specific values of ‘nitrogen produced per year’. There are likewise a range of categories for pigs, sheep, poultry, goats, deer, and horses.
You also need to take into account any organic manures exported/imported from/to the farm.
It is complicated: there’s no denying that. But it’s not as complicated as it sounds, and there are some helpful calculators available, such as mine.
2. Evidence of your manure and slurry storage capacity calculations
If you produce any slurry, you must show that you have enough storage capacity to store that slurry for the entire ‘storage period’ (5 months, or 6 if you have pigs or poultry, starting the 1st of October).
Working out your farm’s slurry storage capacity only needs to be done once (and only updated if anything significant changes), but you will still need to calculate the excreta output for your specific cattle population (using DEFRA’s ‘standard values tables’ mentioned above) every year to show compliance.
Additionally, you must calculate that you have sufficient storage for any ‘rainfall, washings or other liquid that enters the store during the storage period’, allowing for a ‘wetter than average rainfall’ which they define as the wettest year in five. This also needs to be updated every year.
Again, there are calculators to help with this, such as the ‘Slurry Wizard’: at this stage, this calculation’s got so specified and complicated that the Slurry Wizard is really the only viable option.
If you do not produce any slurry, you must have records to show that your farmyard manure is stored appropriately. Often this is a simple matter of recording the location of ‘temporary field heaps’ (i.e. muck heaps or middens), which is taken care of by having an up-to-date ‘Farm Risk Map’ (see below).
3. A farm ‘risk map’ detailing:
a) The area (in ha) of each field
b) Any rivers, streams, or surface water
c) Any boreholes, wells, or springs on or within 50m of your land
d) Any drains or ditches
e) Soil type (for each field), particularly any shallow or sandy soils
f) Any slopes (slight/moderate/severe)
g) The location of any existing or planned muck heaps
h) Any ‘no-spread’ areas: e.g., within 10m of any surface water and/or 50m of any borehole, well, or spring.
i) Any fields considered ‘low-risk’ for spreading (for the purpose of mitigating any shortfalls in slurry storage capacity)
Unless there are any significant changes (to drainage, e.g.), this map only really needs to be updated with regard to the location of muck heaps: the rest won’t change year-to-year.
Nonetheless, if you’re using muck heaps, this map will need to be updated every year (or technically ‘within 3 months of any changes’) as, according to the NVZ rules, you must move ‘temporary field heaps’ at least every 12 months, leaving a 2 year gap before returning to the same site.
This means a two-year old map (with a muck heap marked) breaks the rules either way: if it’s inaccurate, then it hasn’t recorded any changes; if it’s accurate, then the muck heap’s been there too long.
So, this map needs to be updated at least every year.
4. Records of all spreading activity in the previous year, including:
– a) ‘Field Limit’ calculations: to show you haven’t spread more organic manure than you should’ve in any one field. The field limit in an NVZ is 250kg N/ha from organic manures: that is total nitrogen, not crop available nitrogen.
– b) ‘N-Max Limit’ calculations: to show you haven’t spread more crop available nitrogen (in any form) than you should’ve in any one field, according to crop type. For grassland, this often doesn’t require an additional calculation but only a record of total N spread, as most people don’t get anywhere near the N-Max Limit.
– c) These records can also be used as a basis for the ‘Soil Nitrogen Supply’ (SNS) calculation (necessary for the ‘4-step Nitrogen Plan’ detailed below) for grassland, since, according to the AHDB’s ‘RB209: Nutrient Management Guide’ (Section 3, p. 12): ‘Nitrogen fertiliser, organic manure use and management history in the last 1–3 years are of most importance for determining the SNS status [of grassland].’
According to the NVZ rules, you must record any spreading activity. But, while not necessary according to the NVZ rules, it’s also worth recording any other SNS- or N-Max-significant activity on a field-by-field basis, such as grazing or cutting: the SNS status is lowered in fields where there has been significant cutting but not much spreading or grazing, e.g., and the N-Max limit for grassland is raised (by 40kg/ha) for any field where you cut 3 times or more.
Given that the SNS status must be calculated every year (for each field), it follows that any cutting/grazing activity ought to be recorded (in some form) for the purpose of the SNS calculation.
5. A ‘4-step Nitrogen Plan’ for the year ahead, including:
– a) Calculation of the ‘Soil Nitrogen Supply’ (SNS) status for each field
– b) Calculation of the nitrogen requirement for each field, according to crop, accounting for SNS
– c) Calculation of the crop available nitrogen from any organic manures to be spread on each field
– d) Calculation of any additional nitrogen from manufactured fertilisers to be spread on each field
To comply with NVZ rules, you need to show that you have not and will not exceed the NVZ limits.
You can do this on paper, ‘field record by field record’, which is all that’s required for the rules, but in practice (using my method) you can satisfy all of these conditions, as well as producing something actually useful, with some simple maps. For example, I have a map that shows the recommended (according to RB209) amount of nitrogen required for each field in terms of crop available nitrogen from organic manures (up to the NVZ field limit) as well as any supplementary manufactured fertiliser. This incorporates all parts of the ‘4-Step Nitrogen Plan’ in one whole-farm map, and the information can be presented in a way that is practical and useful, such as by showing the NVZ limits for any particular field in terms of ‘tonnes of FYM’ or ‘loads of spreader’.
Additional Rules: Closed Periods
In an NVZ, you must not spread organic manures with ‘high readily available nitrogen’ (i.e., 30% or more of the total N is crop available: this basically means all slurries, and poultry manure) within these periods:
For grassland: 15th of October to 31st of January (or 1st of September to 31st of December, for shallow or sandy soils).
For tillage land: 1st of October to 31st of January (or 1st of August to 31st of December, for shallow or sandy soils).
Additionally, you must not spread any manufactured fertiliser within these periods:
For grassland: 15th of September to 15th of January
For tillage land: 1st of September to 15th of January
There are some exceptions, such as for early-sown crops, and there are some additional restrictions on how much you can spread in February. See DEFRA’s pages for more details.
To show compliance with these rules, it follows that at least four things need to be recorded for each field in which any spreading occurs: a) soil type, b) crop type, c) fertiliser type, and d) date of application.
Additional General Requirement
Finally, a bonus extra requirement that everyone has to comply with according to the ‘Farming Rules for Water‘, whether or not you’re in an NVZ:
6. You must get your soil tested at least once every five years, and use those results in your nutrient planning.
This applies to all ‘cultivated agricultural land’, which they define as any land that has had any spreading at any point in the last three years (as well as any land that has been ploughed, sowed, or harvested in the past year).
So if you do any spreading on your land then you’ll need to get your soil tested for pH, phosphorus, potassium, and magnesium, at least once every five years.
Again, you can do this yourself: just take a sample and send it off to a lab. Or you can pay someone like me to do it. For soil sampling I tend to only work locally (Wiltshire and the surrounding counties).