With the price of Ammonium Nitrate fertiliser set to climb above £700 per tonne (Farmers Guardian 22/11/2021), James Daniel of Precision Grazing and I discuss on a new YouTube video how farmers can reduce their reliance on artificial nitrogen fertiliser whist achieving the most profitable level of production. You can watch the video below, or by clicking here.
In the video, James first points out that nitrogen is a growth promoter which enables a yield response when applied. Historically it has appeared to be a “cheap” form of additional feed, however at current nitrogen prices the cost is now £0.15-20/kgDM. As a comparison a round bale of silage at £25 would be £0.10/kgDM. This means if the farm is to protect its profitability some careful planning is needed.
The use of artificial nitrogen has come at a cost to soil health, displacing the ‘nitrogen fixing bacteria’ which can exist in a healthy soil as well as depleting soil organic carbon (also a source of nitrogen and moisture). Farms that have used “high” amounts (>200kgN/ha/year) will have plants that are addicted to artificial nitrogen and so need to carefully plan how they manage any reduction in 2022.
It is important to recognise that Nitrogen response curves are “non-linear” meaning that for every additional kg of nitrogen applied you get a smaller and smaller response. Therefore, due to the increase in cost James suggests that it is not economically viable to apply more than 45kgN/ha in a single application. James then goes on to state that nitrogen efficiency can be influenced by a number of factors linked to soil health and management. Improving in these areas will help the farm grow more pasture (without Nitrogen feriliser) as well as increasing the response rate when it is used – a Win-Win!
To view the slides used in the presentation, click here.
Action plan for reducing Nitrogen Fertiliser usage in 2022
- Basic or full mineral soil test for any fields not tested in the last 3 years (10x tests available FOC from PLP!)
- PH correction (target 6.5 for mineral soils) through application of Lime (preferred over sand due to quicker response rate)
- Soil structure assessment – using spade – looking for signs of compaction which will prevent air moving in the soil and limit the ability of nitrogen fixing bacteria to work. (on farm assessment service and aerator hire available from PLP).
- Changes in grazing management can lead to increases of between 1t – 3tDM per hectare.
- Reduce the amount of time animals spend in one field or paddock by increasing the group size or splitting the area in half using electric fencing
- Provide an appropriate rest period to allow the plants to recover by having a least 8 fields or paddocks per group on animals.
- Testing of slurry / manure on farm to assess their nutrient value
- Identify any deficient which will need correction via a bagged product.
- Seek independent advice
Alternative Forage Sources
- Consider renting additional land (for forage production) or purchasing standing grass (if possible)
- Purchase of silage or hay
- Purchase of concentrate (although cost is high at ~£0.25-30/kgDM)
- Carry no passengers - prompt sale of any animals which are poor performers.
- Sale of trading stock (store cattle or lambs)
- Reduction in breeding cow/sheep number
- Only apply once soil is greater than 8 degrees
- Limit applications to maximum of 25kgN/ha on grazing fields and 45kgN/ha on silage fields
- Target applications on fields with correct PH and youngest pasture (for best response)
- Clover sown in 2022 will not provide nitrogen until 2023. However it should still be established to prepare for 2023!
- Establish white clover in March and April following the first grazing event
- Establish red clover in May or June following the first silage cut
- Ensure soil PH is >6
- Ensure sward has >10% bare soil to enable plants space to establish
- Mix of grasses, herbs and legumes which are capable or matching or exceeding the yield of ryegrass + 250kgN
- Can be established as part of a Countryside Stewardship Scheme – advice available from PLP
If you would like any further advice on grassland management, please contact James Daniel, Precision Grazing at firstname.lastname@example.org or on his mobile 07534 930484.
Here at the Penwith Landscape Partnership we can offer up to 10 free soils samples, free soil compaction reports and the hire of our aerator at the low cost of £60 per day. If you are interested please contact Philip Pengelly by email at email@example.com or by mobile 07976 731376.