Arecanut (Areca catechu L.), which belongs to the family palmae, is one of the most important plantation crops in humid tropical areas. In recent years, demand for Arecanut has increased rapidly and the planted area of Hainan Province has multiplied. However, the average yield per unit area of Arecanut remains low. Appropriate fertilizer should be applied to Arecanut soil to improve its production. Arecanut was used the seed and peel as medicine, containing 0.3%-0.6% of alkaloid, gives priority to arecoline (0.1%-0.5%). Long-term clinical practice proves: Arecanut has an efficacy of attacking impaction, killing pests and running water, which was used as roborant, digestant, astringent, antimalarial, decongestant, antitussive and emmenagogue. It can be prepared into the pills for diuresis, curing diarrhea, abdominal distension pain, edema, lumbago and bronchus, and also a specific remedy for preventing and curing tapeworms, roundworms, fasciolopsiasis and maw worm of livestock. In situ experiments combined with venting were conducted to study the effects of different fertilization patterns and irrigation on ammonia volatilization from soil in two growth seasons of Areca catechu L. The results showed that the peak ammonia volatilization rate (0.50-3.42 kg · hm^-2 · d^-1) occurred in the third day after irrigation and fertilization at the recovering and flowering stages, then declined and entered a low volatilization phase. The peak ammonia volatilization rate (1.50-4.42 kg · hm^-2 · d^-1) at the flowering stages was significantly higher than that at the recovering stages, because the amounts of ammonia volatilization at low irrigation volumes (300 m³ /hm²) were less than those at high irrigation volumes (600 m³ /hm²). At the same level of nitrogen, the soil with a low organic matter content had higher ammonia volatilization, and when the soil organic matter content was the same, the ammonia volatilization rate increased with increasing N fertilizer levels. Compared with a single application of N fertilizer, the combination of organic manure and N fertilizer can significantly reduce the ammonia volatilization rate, thus reducing total nitrogen loss.