Our Organisation Search
Quick Links
Toggle: Topics

Grassland

Dairy

Nitrogen fertiliser advice for dairy grazing

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 (units/acre in brackets).

See link to Early N Advice Guidelines for efficient use & response Grasslandhttps://www.teagasc.ie/media/website/environment/soil/Early-Nitrogen-Advice---Grassland.pdf

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 dairy grazed swards*

Table 2:- Simplified P requirements (kg/ha) of grazed swards on dairy farms. (Rates shown are total P requirements, before deductions for concentrate feeds or organic fertilizers).

Note

  • Rates shown must be deducted to account for P fed to livestock in concentrate feeds.
  • 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.

Potassium (K) for dairy grazed swards*

Table 3:- Simplified K requirements (kg/ha) of grazed swards on dairy farms. (Rates shown are total K requirements, before deductions for organic fertilizers).

 

Fertiliser Values for Cattle Slurry

 

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

 Sulphur

  • 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.

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.

Fertiliser Requirements at P & K Indexes 1 to 4 & Suggested N, P & K Programmes

 Fertiliser programme showing splits & fertiliser products & N, P & K timings

 

 

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 (units/acre in brackets)

See link to Early N Advice Guidelines for efficient use & response. Grasslandhttps://www.teagasc.ie/media/website/environment/soil/Early-Nitrogen-Advice---Grassland.pdf

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 cattle grazed swards**

Table 2:- Simplified P requirements (kg/ha) of grazed swards on dairy farms. (Rates shown are total P requirements, before deductions for concentrate feeds or organic fertilisers).

  • Rates shown must be deducted to account for P fed to livestock in concentrate feeds.
  • 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.

Potassium (K) for cattle grazed swards**

Table 3:- Simplified K requirements (kg/ha) of grazed swards on dairy farms. (Rates shown are total K requirements, before deductions for organic fertilisers).

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

Fertiliser Values for Cattle Slurry

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

Sulphur

  • 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.

S fertilizer 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.

Fertiliser Requirements at P & K Indexes 1 to 4 & Suggested N, P & K Programmes

Fertiliser programme showing splits & fertiliser products & N, P & K timings

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.

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) advice for sheep grazed swards**

Table 2:- Simplified P requirements (kg/ha) of grazed swards on sheep farms. (Rates shown are total P requirements, before deductions for concentrate feeds or organic fertilizers).

Note

  • Rates shown must be deducted to account for P fed to livestock in concentrate feeds.
  • 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.

Potassium (K) advice for sheep grazed swards**

Table 3:- Simplified K requirements (kg/ha) of grazed swards on dairy farms. (Rates shown are total K requirements, before deductions for organic fertilizers).

Fertiliser Values for Cattle Slurry

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

Sulphur

  • 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.

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.

Fertiliser Requirements at P & K Indexes 1 to 4 & Suggested N, P & K Programmes

Fertiliser programme showing splits & fertiliser products & N, P & K timings

Fertiliser programme showing splits & fertiliser products & N, P & K timings

Grass Silage/Hay

N fertiliser advice for cut swards

Rates of fertiliser N are shown as kg/ha

Table 1:- Nitrogen Rates for Cut Swards
CropN application rate (kg/ha)
Silage (1st Cut) 125
Silage (2nd or subsequent cuts) 100
Hay 65 - 80

Rates shown above refer to application of available N. Chemical fertilizer rates should be calculated by deducting the available N contained in organic fertilizer applications from the rates shown in the table above.
If N is applied for early grazing, assume that 20% of this remains available for first cut silage.
An extra 25 kg/ha may be used where necessary for establishment of a good ryegrass sward if pasture is less than 4 years old, provided that the maximum N allowed within the nitrates regulations is complied with.
Where silage fields were grazed rather than cut in the previous year, apply 100 kg/ha for first cut, and 85 kg/ha for second and subsequent cuts.
When more than 2 cuts are taken there is a danger that the allowance in the nitrates regulations will be exceeded.
Less N is advised for hay crops when there is a high risk of crop loss due to high rainfall.

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).

Soil IndexCut Once2nd and subsequent cuts
 P (kg/ha)K (kg/ha)P (kg/ha)K (kg/ha)
1 40 175 10 70
2 30 150 10 55
3 20 120 10 35
4 0 0 0 0
  • 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 1st 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 1st Cut Grass Silage

N, P & K Recommendation’s for 1st cut grass silage
N Advice
kg/ha
Soil P & K IndexP
kg/ha
K
K/ha
Fertiliser Programme
(bags/ac)
120
(96 units/ac)

(  )= units/ac
1* 40 (32) 175 (140) 3 bags x 0-7-30
3.5 bags CAN
2* 30 (24) 150 (120) 3 bags x 0-7-30
3.5 bags CAN
3 20 (16) 120 (96) 2.6  bags x 13-6-20
3 bags 20-0-15
4 0 0 3.5 bags CAN
*Apply remaining P & K after 1st cut silage

 

Suggested Fertiliser (N, P & K) Programme for 1st Cut Grass Silage where 33m³/ha (3,000 gallon/ac) of cattle slurry is applied

N, P & K Recommendation’s for 1st cut grass silage adjusted for 33m³/ha (3,000 gal/ac) of cattle slurry (7% DM)
N Advice
kg/ha
Soil P & K IndexP
kg/ha
K
K/ha
Fertiliser Programme
(bags/ac)
120
(96 units/ac)

(  )= units/ac
1* 20 (16) 65 (52) 3bags 24-2.5-10
2* 10 (8) 40 (32) 2bags 24-2.5-10
1.0 bags CAN
3 0 10 (8) 2.8 bags 20-0-15
0 0 2.8 bags CAN
*Apply remaining P & K after 1st cut silage
¹Apply straight N to Index 4 P & K fields

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

Fertiliser Requirements at P & K Indexes 1 to 4 & Suggested N, P & K Programmes for 1st Cut Grass Silage

Suggested Fertiliser (N, P & K) Programme for 1st Cut Grass Silage where 33m³/ha (3,000 gallon/ac) of cattle slurry is applied