Effect of balanced fertilization on production of pineapple in Hainan

On Hainan Island, pineapple is usually grown on the sand-gravel soils. These soils are very acidic and poor in soil fertility due to very low cation exchange capacity and high leachability. Even so, this soil-type is still considered best suited to pineapple. According to past research and common experience, the crop does not grow well on heavy-textured, more fertile soils. However, since the island is frequently affected by heavy thunderstorms in the summer season, high nutrient losses through leaching can occur and this problem is accentuated by improper fertilization. This issue leads to lower fruit yield and quality, higher production costs, and increased environmental risk. Designing an appropriate fertilizer program for high yield and high fertilizer use efficiency can be challenging under such conditions. The objective of this study was to investigate the effect of fertilizer treatment on yield and quality of pineapple and develop fertilizer best management practices. The experiment consists of six treatments, including an optimal treatment (OPT) with 360-180-720-72 kg N-P₂O₅-K₂O-MgO/ha and a series of nutrient omission treatments.

Soil testing, and subsequent field study, indicated that soil N, P, K, and Mg all limited pineapple production. Compared to the OPT, pineapple yield was significantly reduced under each individual nutrient omission treatment. The -K treatment significantly reduced contents of vitamin C and all the treatments had slight lower contents of soluble sugar in harvested fruit compared to the OPT. Agronomic efficiency (kg fruit increase per kg added nutrient) was measured at 33, 24.4, 11.7, and 90.5 kg fruit for per kg of N, P₂O₅, K₂O, and MgO. Similar to research data obtained in Guangxi, more than 90% of these nutrients remained in the stem and leaf and only a small proportion was transferred to the fruit at harvest, suggesting that recycling of crop residue would be of great value.

These results verified the nutrient limitations for Hainan’s pineapple crops and substantiated the optimal fertilizer rates applicable to similar, large pineapple plantations on the island. Hainan-08