Published online by Cambridge University Press: 27 March 2009
Crops of potatoes grown on 0·2–0·3 ha in each of the years 1971–8 at Stockbridge House Experimental Horticulture Station achieved total tuber yields of 70–94 t/ha. Yield was determined by the period and rate of tuber growth. The observed period of growth varied from 96 to 132 days and the rate from 0·55 to 0·90 t/ha/day. Rate of growth had the greater influence on variability of yield between the years. The number of tubers produced per unit area had little influence on their total weight, but had marked effect on their size. Adequate water supply was essential for very high yields. Experiments indicated that current recommendations for potash fertilizer can be adequate but that nitrogen and phosphate fertilizer use may need to be enhanced for very high yields. For high yields, the number of seeds planted per hectare may need to be higher than normally recommended in order to avoid the production of large tubers unsuitable for the ware market.