Grassland

Dairy

Nitrogen fertiliser advice for dairy grazing

Fertiliser advice is show in table 1.  Rates and timing of N fertilizer applications for swards grazed by cattle at various stocking rates. Rates of fertiliser N are shown as kg/ha.

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) & Potassium (K) for dairy 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

 Sulphur

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

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

 Sulphur

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

Sheep

Nitrogen (N) fertiliser advice sheep grazing

Table 1 gives guideline rates for N applications on sheep pasture with normal to low clover content for a range of stocking rates. The suggested timetable applies to ewes with high productivity assuming that no concentrates are offered at pasture. The N timetable is for early to mid-March lambing, but depends on several factors including overall farm system, soil, climatic conditions, clover content etc.

See link to Early N Advice Guidelines for efficient use & response https://www.teagasc.ie/publications/2022/when-to-apply-early-nitrogen-n.php

The N requirements for sheep grazing are generally lower than for dairy cows or cattle. This is because:

• Less silage is required for sheep than for cattle due to the shorter in-wintering period
• Sheep recycle dung/urine more uniformly to pasture and hence there is less herbage waste around dung-pats and, consequently, more efficient herbage utilisation (more uniform post-grazing height and less high grass left ungrazed)
• There is a better match between feed demand and herbage growth because feed demand is highest from lambing to weaning (March to early July). It decreases post weaning as lambs are drafted for sale and ewes can be restricted to maintenance feeding
• Clover survival can be encouraged by rotational grazing rather than continuous sheep grazing as sheep preferentially graze clover plants.

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

Sulphur

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.

Grass Silage/Hay

N fertiliser advice for cut swards

Rates of fertiliser N are shown as kg/ha

P and K for silage

Phosphorus (P) and Potassium (K) for silage

Table 2:- P and K requirements (kg/ha) for grass silage. (Rates shown are total requirements, before deductions for organic fertilisers).

• Silage crops remove more P and K from fields than grazing. Each 1 tonne of grass silage will remove 4kg P and 25kg K per tonne of grass dry matter, respectively.
• Where swards are being harvested for silage, apply the rates of P and K shown below in addition to the grazing requirements.

Fertiliser Values for Cattle Slurry

Cattle slurry is a valuable source of N, P & K and should be applied to silage fields to ensure the return of P and K. This will help maintain P and K levels for optimum production in the farms silage area.  Cattle slurry has the correct P : K ratio for fertilising the grass silage crop.  Table 4 below shows the N, P & K value of slurry and the effect of LESS on slurry N recovery.  33m³/ha of good quality cattle (6% DM) will slurry sufficient P & K to grow a crop of 1^st cut silage on Index 3 P & K soils.  On Index1 & 2 soils reduce P and K availability by 50% and 10%, respectively.  On Index 1 & 2 soils use a high N low P & K fertiliser blend (27’s or 24’s) to complement the P & K in cattle slurry to ensure the crop has sufficient levels.  It is also important to take account of any P & K applied to silage fields prior to closing for silage for example silage ground maybe grazed and may have received an application for example of 18-6-12 in March which will help feed the current silage crop.  See table 5 for suggested fertiliser programmes with and without slurry.

Suggested Fertiliser (N, P & K) Programme for 1^st Cut Grass Silage (Fertiliser Only)

 Table 3. N, P & K requirements for 1^st Cut Grass Silage (5t/ha DM) & suggested fertiliser programmes

*The P and K rates shown can be supplied by either slurry or fertiliser