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.
The Goulding Fertilisers recommendations are based on the Index System as laid out by Teagasc, Johnstown Castle, Co. Wexford. In the recommendations, the soil fertility is divided into 4 indices:
| Table 1. Fertiliser Index System | |||
|---|---|---|---|
| 1 = Very Low | 2 = Low | 3 = Medium | 4 = High |
The Index for Phosphorus (P) and Potassium (K) can be established by a soil test, whereas the Nitrogen (N) Index is based on a knowledge of:
- soil type
- area knowledge
- previous cropping
(a) Phosphourus (P) and Potassium (K) Index System
The Index and the corresponding soil test range for P and K are shown in Table 2 Below:
| Index | Soil P ranges (mg/l) | Soil K ranges (mg/l) | |
|---|---|---|---|
| Grassland | Other Crops | Grassland and Other Crops | |
| 1 | 0 – 3.0 | 0 – 3.0 | 0 – 50 |
| 2 | 3.1 – 5.0 | 3.1 – 6.0 | 51 – 100 |
| 3 | 5.1 – 8.0 | 6.1 – 10.0 | 101 – 150 |
| 4 | > 8.1 | > 10.1 | > 150 |
| Table 3. Phosphorus (P) and Potassium (K) response at the Index range | |
|---|---|
| Index | Response Level |
| 1 Very Low | Nutrient response definite |
| 2 Low | Nutrient response likely |
| 3 Medium | Nutrient response unlikely, except for root crops, but maintenance dressing should be used |
| 4 High | Nutrient levels adequate, Maintenance dressings not necessary at presence except for potatoes |
(b) Nitrogen (N) Index System
The Nitrogen Recommendations are based on the requirements of each particular crop, taking into account:
- the previous cropping
- the manuring history of the field
- the soil type
| Index | Response Level |
|---|---|
| 1 Very Low | Small release of soil Nitrogen (N) (continous tillage) |
| 2 Low | Medium release of soil Nitrogen (N) |
| 3 Medium | Large release of soil Nitrogen (N) |
| 4 High | Very large release of soil Nitrogen (N) |
Tillage / Pasture Establishment:
| Continuous tillage: — crops that follow short leys (1-4 years) or tillage crops | |||
|---|---|---|---|
| Previous crop | |||
| Index 1 | Index 2 | Index 3 | Index 4 |
| Cereals, Maize | Sugar beet, Fodder beet, Potatoes, Mangels, Kale, Oil seed rape, Peas, Beans | ||
| Leys (1-4 years) grazed or cut and grazed. | |||
| Swedes removed | Swedes grazed in sitiu | ||
| Vegetables receiving less than 200 kg/ha nitrogen | Vegetables receiving more than 200 kg/hanitrogen | ||
| Tillage crops following permanent pasture | |||
|---|---|---|---|
| Nitrogen Index | |||
| Index 1 | Index 2 | Index 3 | Index 4 |
| The 5th tillage crop following permanent pasture. For subsequent tillage crops use the continuous tillage table | The 3rd or 4th tillage crop following permanent pasture. If original permanent was cut only use index 1 | The 1st or 2nd tillage crop following permanent pasture (see also Index 4). If original permanent pasture was cut only, use index 2 | The 1st or 2nd tillage crop following very good permanent pasture which was grazed only |
Grassland
The Nitrogen Index is not very useful for grassland as it depends on:
- the stocking rate
- age of the ley
- variety of grasses in the sward
- clover content
Under a grazing situation, newly re-seeded leys generally need more Nitrogen in the first three years of production than in succeeding years.
(c) Sulphur
Some thirty percent of our soils require Sulphur for optimum yields because:
- Fertilisers containing high sulphur contents are used little nowadays.
- Sulphur deposition on land has declined because of lower emissions from industry. The soils most likely to show Sulphur deficiencies are sandy, free draining soils with a low organic matter content. As the sulphate ion leaches readily from soils, it is not worthwhile trying to build-up soil sulphur levels.
| Table 7. Teagasc recommended application rates of Sulphur | |
|---|---|
| Grazing | 10-20 units/acre/yr |
| Silage | 15-20 units/acre/cut |
| Cereals | 15-20 units/acre/yr |
| Roots | 15-20 units/acre/yr |
Gouldings produce a large range of core products with or without Sulphur. For information on these products view our product range.
