Effect of various N application times on tree phenology and physiology of 'Mauritius' litchi in South Africa - preliminary results
The post-harvest shoot growth cycle is a period to foster strong bearing shoots for the next season as high quality bearing shoots are the basis for a productive tree. In South Africa soil application of fertilizers in litchi is generally done 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, a trial was conducted in the early production area of South Africa (near Malelane) on the cultivar 'Mauritius' ('Tai So') during 2014. Soil applications of nitrogen were done as follows: a) single application during last part of harvest, b) single application after harvest, c) split application during the last part of harvest and at hardening of the first post-harvest flush, d) no post-harvest application (application only before flowering) and e) current practice on trial farm (after harvest application). Soil and leaf nutrient analysis was done to determine the requirement of N for applications. All other nutrients were applied in relation to the N amount. Tree phenology was monitored on a regular basis. Data for leaf N, tree starch content, shoot growth, flowering and yield were collected. The results show that time of N application affects the time of flush emergence, hardening-off time and leaf N content. Tree starch content and leaf N at specific times were positively correlated to shoot growth, flowering and yield. However, further research is underway to confirm the above results.
Cronje, R.B. and Ratlapane, I.M. (2018). Effect of various N application times on tree phenology and physiology of 'Mauritius' litchi in South Africa - preliminary results. Acta Hortic. 1211, 7-14
flowering, leaf N, shoot growth, starch reserves, yield