The recommendations in this section are using the RoI fertiliser classification system and are based on Teagasc research. Due to slight differences between the RoI and NI classification systems, these recommendations are only a guide for Northern Ireland farmers. They can be converted between the RoI and NI classification systems using this CONVERSION TABLE
Before choosing your fertiliser products please consult your local advisor to ensure that you do not exceed the limits for your farm as determined by the nitrates directive (SI no 378) of 2006.
Table 36. Nutrient Requirements (unit/acre)
Index
N
P
K
1 Very Low
108
36
76
2 Low
80
28
60
3 Medium
60
20
48
4 High
32
0
0
The nitrogen recommendations in the above Table are for light shallow soils.
-
If straw is ploughed in or burnt, decrease Phosphorus (P) rates by 5 units and Potassium (K) by 15 units
-
These
recommendations are based on the maximum nitrogen and phosphate levels permitted
-
Malting
barley should not be grown on soils with soil Nitrogen index 3 or over. Top dressing of Nitrogen should be at the 3-4 leaf stage
-
Where proof of higher yields is available, an additional 20kg N/ha may be applied for each additional tonne above the following yields;
Spring Barley - 7.5 tonnes/ha
The higher yields shall be based on the best yield achieved in any of the three previous harvests, at 20% moisture content.
2½ x (10-10-20)
+
2 x (Classic NK) as Top Dressing
2¾ x (10-10-20)
3 x
(10-10-20)
2 x
(16% Superphos)
P3 Medium
2 x (10-10-20) + 2 x
(Classic NK)
as Top Dressing
3½ x (10-10-20)
+
1½ x (Classic NK) as Top Dressing
3 x
(18-6-12)
1¼ x
(16% Superphos)
P4 High
1½ x
(Muriate of Potash 50%)
1¼ x
(Muriate of Potash 50%)
1 x
(Muriate of Potash 50%)
No P or K Required
Top Dressing:
Nitrogen (N) C.A.N. or Urea can be used to satisfy the extra Nitrogen requirements of the crop.
Early sown crops: In these cases ½ of a 50kg bag/acre of 10-10-20 can be withheld from the seedbed. The Phosphorus (P) and Potassium (K) requirement can be fulfilled by applying 2 x 50kg bags/acre of Richland as a top dressing. There are clear advantages in applying some P and K as a top dressing when the plant is tillering and the roots are established enough to take in the nutrients.
Richland: 22.7 - 2.5 - 5 + 3% Sulphur (S) + Copper (Cu), Manganese (Mn), Magnesium (Mg) and Zinc (Zn). The unique blend of N, P, K with Sulphur and vital trace elements make it an excellent option for top dressing spring cereals.
Sulphur (S) should be used on crops up to the Teagasc recommended level of 12 units/S/acre.
