Grassland
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 | |
---|---|
Crop | N 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. |
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 Index | Cut Once | 2nd 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 Index | P 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 Index | P 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 | |
4¹ | 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