Effects of nitrogen fertilizer applied to seed crops on seed yields and regrowth of progeny tubers in potatoes

Abstract

SUMMARYThree experiments, carried out in 3 years (1972–5), which examined the effects of a wide range of rates of nitrogen fertilizer applied to seed crops of Home Guard on seed and progeny crop growth are reported. There was little effect of increasing rate of N application over the range 0–300 kg/ha on seed yield, and the results suggested that very low rates of nitrogen fertilizer (< 75 kg/ha) were required for maximum seed yield in mid-Wales. Increasing the rate of nitrogen fertilizer above 304 kg/ha delayed growth and decreased yield in seed crops. Although increasing the rate of nitrogen fertilizer in seed crops delayed senescence and increased the nitrogen concentration of tubers, there were few consistent effects on sprouting or growth of progeny crops.Close negatively quadratic relationships were found between the dry-matter content of tubers and their size. The dry-matter content of all sizes of tubers increased during growth, but there were no effects of nitrogen on dry-matter content.