Grassland - Beef
Nitrogen (N) fertilizer advice for grazing
Rates and timing of N fertilizer applications for swards grazed by suckler calf to weaning at various stocking rates. Rates of fertilizer N are shown as kg/ha. Refer to Teagasc Green Book for N advice for other dry stock systems.
See link to Early N Advice Guidelines for efficient use & response https://www.teagasc.ie/publications/2022/when-to-apply-early-nitrogen-n.php
Nitrogen (N) requirements for pasture
- There is no reliable soil test currently available for N. Therefore, there is no soil Index system for N in grassland.
- Recommendations are based on average soil fertility levels.
- Total N application and on the farm and time of application must be compliant with nitrates regulations.
- Matching nitrogen fertilizer use to stocking density on the farm at different times of the year avoids excessive use.
- Applying nitrogen fertilizer ‘little and often’ during the growing season gives most efficient response in terms of grass growth.
Phosphorus (P) for drystock grazed swards*
- Rates shown must be deducted to account for P fed to livestock in concentrate feeds
- Adjust rates based on slurry management as per fertiliser plan.
- To account for P in concentrate feeds, use either actual P content in the feeds used if available, or alternatively, use a default value of 5 kg of P per tonne of concentrate feed.
- Complete a farm fertiliser plan to determine farm N & P allowances.
Fertiliser Values for Cattle Slurry
Figure 1. Grass yield responses to sulphur applied on a range of soil types. Grass yield responses to S range from 1.0 to 3t/ha from heavy to light soil types.
- Sulphur (S) is an important nutrient for grassland, and is closely associated with N uptake and efficiency.
- There is currently no soil test or soil Index system for S.
- Herbage analysis is the best predictor of S deficiency.
- Lighter soils with low organic matter contents are generally more prone to S deficiency.
Figure 2. Map indicating areas of possible S deficiency
S fertiliser advice
- The response to S fertiliser increases as the rate of N fertiliser increases.
- On S deficient soils, apply 20 kg/ha per year for grazed swards.
- For silage swards on S deficient soils, apply 20 kg/ha of S per cut.
- Avoid S application to soils not deficient in S, as excess S may affect the trace element nutrition of plants and animals.
- S can be applied by using any of a number of straight or compound fertilizers that contain S.
- Aim to apply S containing fertilisers from March / April to June