Pg. 32-34 Effect of Phosphorus and Potassium Fertilization on Lychee Production over Three Years

Phosphorus (P) and potassium (K) were applied to lychee (litchi) trees at three sites in subtropical Queensland, Australia (lat 27°S) to determine the effects on leaf nutrient concentrations and fruit production. Applications were equivalent to 0 to 2.4 t per ha for P, and 0 to 3.2 t per ha for K. In the first two years, there was no effect of fertilizer on leaf P and K, while in year three, leaf P was related to P application at two out of two sites and leaf K to fertilizer K at one out of three sites. Thus, P and K accumulated at some sites at high rates of fertilization. In contrast, levels in control unfertilized trees fell only slightly over time. Generally, fruit production was similar over the range in leaf P of 0.18 – 0.44% and leaf K of 0. 75 – 1.37%, compared with the Australian standards of 0.14 – 0.22% and 0.70 – 1.10%, respectively. The buffering capacities of lychee soils and trees are thus indicated. These results suggest that annual applications of P and K may not be required, indicating savings for lychee growers.