The XiShi pomelo (Thai pomelo) was introduced to and promoted in Taiwan since 1988. It is propagated by grafting. This evergreen fruit tree features sweet and juicy champagne pink fruit flesh, the high sugar content of which earns it the nickname “honey pomelo.” A traditional XiShi pomelo orchard usually keeps the water supply at a lower level. Therefore higher amount of fertilizer is often applied with higher input of N (especially organic fertilizer such as soybean waste after oil extraction). Under such traditional practice, the onset of rainfall often causes the fertilizer in the soil, especially N, to dissolve in large quantity, triggering vigorous tree growth and shoot sprouting. If this happens during flowering or fruiting stages, flower shedding and fruit dropping are prone to ensue. If it happens during fruit development stage, it may result in split fruit, thick rind and dry pulp. If it happens before harvesting, then quality like sugar content would decline. These problems pose serious challenges to the farmers.

    To help farmers to tackle the challenges, TARI has developed a healthy management system for production of safe, high quality pomelo that also takes account of environmental sustainability and reasonable inputs. Under this system, high yields and high quality of fruit can be achieved just by supplying the fruit trees with adequate and balanced amounts of nutrients in a low-cost and efficient manner. The integrated fertilizer and water management is based on the soil’s physical and chemical properties, weather conditions and growth stages. The control of pests and diseases and stability of fruit quality also meet expected standards. There is no obvious occurrence of pests and diseases, and the fruit is sweet and juicy with thin rind and thick and fine flesh. The sugar content of the freshly harvested XiShi pomelo steadily maintains at 12.3-14.4°Brix, and acidity at 0.19-0.20% citric acid. Compared to traditional practice, which produces fruit with sugar contents of 9.2-10.6°Brix and acidity of 0.19% citric acid, the new management system produces fruit with similar acidity, but significantly higher sugar contents. And the yields increase from 12,000-16,000 kg/ha under traditional practice to 25,000-28,000 kg/ha (an increase of 75-108%). The total revenues also increase from NT$0.5-1.5 million/ha under traditional practice to NT$2-3 million/ha (an increase of 100-300%). It is a great feat.