Pg. 41-48 Fostering strong bearing branches after harvest to increase the yield potential of litchi

The post-harvest shoot growth cycle is a period for fostering strong bearing branches for the next season, as high quality bearing branches are the basis for a productive tree. In South Africa, soil applications of fertilisers are generally carried out immediately after harvest irrespective of production area, number of post-harvest flushes and soil type. In order to determine the effect of various application times, specifically of nitrogen (N), before and after harvest, trials were conducted in both early (Malalane) and mid-season (Nelspruit) production areas on ‘Mauritius’ litchi trees between 2014 and 2016. In the early area, N applications were applied as follows: a) single application at start of harvest, b) single application after harvest, c) split application at start of harvest and at hardening of first post-harvest flush to strengthen second flush, d) no post-harvest application (all N applied before flowering; control 1) and e) farm practice (control 2). Treatments for the mid-season area were the same except that the split application (c) was applied before and after harvest (3-4 weeks apart) as there is only one post-harvest flush. The results showed that time of N application affects time of flush emergence, hardening-off time and leaf N content of the leaves. Tree starch content and leaf N at specific times were positively correlated with shoot growth, flowering and yield.

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