Nutrient Management on Dragon Fruit

This project was initiated in 2011 to refine the fertilizer recommendations for red dragon fruit production in Guangxi Province. The initial experiment consisted of eight treatments replicated three times. Treatments included an optimal treatment (OPT) with fertilizer application rates of 411-188-675-150-1.3 kg N-P₂O₅-K₂O-MgO-B/ha, OPT-N, OPT-P, OPT-K, OPT-1/2K, OPT+1/2K, OPT-Mg, and OPT-B. In 2013, P rate was slightly increased and the range of K rates between low and high was narrowed based on previous year results. However, fertilizer sources, application timing and methods remained the same.

Red dragon fruit yields were much higher in 2013 than in 2012 due to more favorable weather conditions. But similar to 2012, the OPT treatment significantly increased red dragon fruit yield compared to the yields obtained in omission treatments. For example, omitting N, P, K, Mg, and B led to yield reductions of 11.1 t/ha (-50%), 6.2 t/ha (-28%), 6.4 t/ha (-29%), 1.8 t/ha (-8%), and 0.95 t/ha (-3%), respectively, compared to the OPT treatment. Except for Mg, continued omission of the other four nutrients further expanded the yield gap between OPT and omission treatments from 2012 to 2013. Unlike in 2012, cutting K fertilizer by half in the OPT treatment decreased the fruit yield by 2 t/ha (-9%), while increasing K fertilizer by half increased the fruit yield by 0.6 t/ha (2.5%) compared with OPT. This supports the high K demand of red dragon fruit - a fact also reflected in the fruit K content measured during the past two years. The K content was more than double the N content in fruits. We propose the optimal fertilizer rates for red dragon fruit production in the region as 420-230-650-140-1.3 kg N-P₂O₅-K₂O-MgO-B/ha, respectively.