Index	Nitrogen (Units/ac)	Phosphorus (Units/ac)	Potassium (Units/ac)	Sulphur (Units/ac)
1	168	100	120
2	136	92	96
3	120	80	72
4	96	40	48

1. N rates shown above refer to application rates of available fertilizer. Chemical fertilizer rates should be calculated by deducting the available N contained in organic fertilizer applications from the rates shown in the above table.
2. See accordian below for information on Soil N Index.
3. The Phosphorus fertilization rates for soils which have more than 20% organic matter shall not exceed the amounts permitted for Index 3 soils.
4. P rates shown above refer to recommended application rates of available fertilizer.
5. Chemical fertilizer rates should be calculated by deducting the P contained in organic fertilizer applications from the rates shown in the above table.

Index	Nitrogen (kg/ha)	Phosphorus (kg/ha)	Potassium (kg/ha)	Sulphur (kg/ha)
1	210	125	150
2	170	115	120
3	150	100	90
4	120	50	60

1.  

   1. N rates shown above refer to application rates of available fertilizer. Chemical fertilizer rates should be calculated by deducting the available N contained in organic fertilizer applications from the rates shown in the above table.
   2. See accordian below for information on Soil N Index.
   3. The Phosphorus fertilization rates for soils which have more than 20% organic matter shall not exceed the amounts permitted for Index 3 soils.
   4. P rates shown above refer to recommended application rates of available fertilizer.
   5. Chemical fertilizer rates should be calculated by deducting the P contained in organic fertilizer applications from the rates shown in the above table.

[table “” not found /]

1. Assuming no organic manures are supplied
2. Assuming Nitrogen Index = 1

There is, as yet, no satisfactory Irish laboratory test for N in soils at farm level.

1. Nutrient N advice for grassland systems (grazing and conservation) depends mainly on land use and farming system, and particularly on the stocking rate.
2. For crops requiring cultivation, the available soil N can be deduced from the previous cropping and manurial history, and the type of soil. Thus, N fertilizer advice is determined by the soil N supply status. This depends in turn on the previous cropping history.

The supply status is categorised into an Index system for grass establishment and tillage crops.

N Index for tillage crops that follow short leys or tillage

N Index for pasture establishment or tillage crops that follow long leys or permanent pasture

1. Potatoes can grow very well below pH 6.0 however it is necessary to maintain the soil at a
   pH suitable for the other crops in the rotation.
2. In a crop rotation with cereals on mineral soils
   target soil pH levels of 6.3 for oats and 6.5 for most cereals will be required.
3. Lime can take
   years for full reaction with soil, and therefore needs to be applied in good time.
4. Common scab
   is caused by the organism Streptomyces scabies which is endemic in soils, and infection can be exacerbated by fresh applications of lime.
5. Lime should not be applied within the
   two years preceding a potato crop because of the increased risk of common scab.
6. At least 4 years should intervene between liming and sowing a seed potato crop.
7. Check out the Fertilizer Association of Ireland technical bulletin for more information on Liming

1. Potassium regulates the amount of water in the plant, where there is insufficient potassium, crops will not use water efficiently.
2. Potassium will also help the crops to withstand stress
   caused by drought, heat, waterlogging, etc.
3. The use of potassium sulphate is associated with higher dry matter crops.
4. Lower dry matter when using potassium chloride can result due to
   higher plant water caused by increased chloride supply.
5. Excessive chloride uptake can also reduce starch content of the tubers.
6. These potential effects of potassium chloride can be mitigated by using lower application rates or applying 6-8 weeks ahead of planting.
7. Goulding Soil Nutrition offer Potassium sulphate products as a straight (sulphur of Potash), blend (Potato Plus + GSOP) and Polysulphate. 
8. Find out more about Polysulphate

1. Magnesium deficiency is occasionally encountered with potatoes, particularly in sandy soils.
2. High K applications in conjunction with high soil K can reduce the availability of soil Mg.
3. Apply 60 kg/ha of Mg for a soil Mg Index of 1 or 35 kg/ha at Index 2.
4. Goulding Soil Nutrition offer Wolf Trax Magnesium DDP as an option to be coated onto fertilisers, Kieserite, a Mg + S fertiliser and Polysuphate (K, Mg, S, Ca) as options to treat Mg deficiencies. Including Magnesium in your fertilisers allows for earlier intervention (seedbed) when magnesium deficiency is a known issue.
5. Find out more about Magnesium

1. AVAIL is a phosphorous fertiliser enhancer.
2. It is specifically designed to protect fertiliser P from being fixed into unavailable forms in the soil by antagonistic elements such as iron, aluminium, calcium and magnesium.
3. Over the last 15 years, many trials have compared the yield increases from using
   phosphate treated with AVAIL against untreated phosphate. Yield increases in potatoes grown using AVAIL are typically in the region of 10-15%
4. For more information check out our page on AVAIL