The effect of the time of application of nitrogen and potassium on the growth of the second early potato, variety Craig's Royal

Abstract

The effect of time of application of nitrogen and potassium on the growth, development and yield of the second early variety Craig's Royal was studied by the technique of growth analysis. There was an indication that witholding nutrients led to the earlier initiation of tubers, but this was of no practical consequence and all treatments affected tuber bulking rate rather than the duration of bulking. Compared with early application, late application of nitrogen depressed tuber yield, although total drymatter yield was not affected. Late application of potassium, however, increased tuber yield; this was associated with an improvement in the recovery of applied potassium. Delaying the application of nitrogen also resulted in its more efficient recovery in the crop. Late application of potassium improved the recovery of early applied nitrogen and vice versa. Reasons are put forward to account for these effects.