Nutrient Management on Dragon Fruit

Red dragon fruit is a high value fruit that has become quite popular in Guangxi, with the area under cultivation expanding rapidly in recent years. However, there is a lack of appropriate nutrient management information to guide growers in the use of fertilizers efficiently while cultivating red dragon. Therefore, a field experiment was conducted to test the optimal rates of N, P and K fertilizers for obtaining high yields of red dragon fruit in Guangxi. It consisted of eight treatments: optimal treatment (OPT) with applications of 411 kg N, 188 kg P₂O₅, 675 kg K₂O, 150 kg MgO, and 1.3 kg B/ha, OPT-N, OPT-P, OPT-K, OPT-1/2K, OPT+1/2K, OPT-Mg and OPT-B and replicated three times. Nitrogen was used as urea, P as single superphosphate, fused calcium-magnesium phosphate in a ratio of 2:1, Mg as MgSO₄, and B as borax. All fertilizers were split applied in late January, late April, early July, and late August.

Results showed that the OPT treatment significantly increased red dragon fruit yield compared to N, P and K omission treatments. Compared to the OPT treatment yield, N, P, K, Mg, and B omission treatments led to yield reductions of 7.5 t/ha (38%), 4.5 t/ha (23%), 3.3 t/ha (17%), 2.0 t/ha (10%), and 0.5 t/ha (2.7%), respectively. Cutting K fertilizer by half increased fruit yield by 950 kg/ha (4.9%), while increasing K fertilizer by half reduced fruit yield by 367 kg/ha (-1.9%) as compared to the yield in OPT treatment. This implied an over-projected initial OPT K rate for red dragon fruit in this experiment and that a reduction in OPT K rate is needed. The agronomic efficiencies of N, P₂O₅ and K₂O were 18, 24 and 5 kg fruit/kg, respectively. Though addition of B did not significantly increase fruit yield, its agronomic efficiency (410 kg fruit/kg B) was the highest of all nutrients in the study, likely due to it's low use rate. Guangxi-BFDP-2012