Recent studies on potato manuring in Ireland

Summary

Lime has not been found of importance for potatoes except on cutaway hochmoor. Nutrient requirements per acre are about 70 lbs nitrogen. 40 lbs phosphorus and 170 lbs potassium. Farmyard manure was found to be a poor source of nitrogen but a good source of phosphorus and potassiu. Different nitrogenous fertilizers in general gave similar results, but calcium cyanamide gave inferior results.

Phosphatic fertilizers, except rock phosphate. generally compared well with superphosphate. Sulphate gave total yieds as high as, and starch yields higher than, muriate of potash.

Growing potatoes for several years under nutrient deficiency did not affect “seed” vigour. Potassium deficiency could not be corrected by spraying but top dressing gave good results. Soil analysis gave good correlation of nutrient level with crop response to applied fertilizer. P and K deficiency had serious adverse effects on tuber size, K being worse in this respect than P deficiency.