Detailed Explanation of Key Points of Carambola Cultivation Techniques in Taiwan, China

In recent years, Taiwan, China has developed excellent varieties through mutations in seedling carambola trees. Combined with improvements in cultivation techniques, the carambola cultivation area has increased year by year, making it an emerging fruit tree.

The carambola harvest period is long, and it can be harvested about 3 times a year, with high yields. Because it is nutritious, the emerging carambola sells well in Taiwan, China, and processing and utilization such as canning, jam, candied fruit, and winemaking are also relatively common. Carambola development has considerable potential.

The yield level and the quality and flavor of carambola, in addition to being related to the variety, are greatly affected by cultivation management techniques. The main management and cultivation techniques are as follows:

1. Pruning and training. Generally, for young branches after planting, it is advisable to prune at 50-60 cm from the main trunk above the ground to promote natural branching, then retain 3-5 branches as main branches to form the tree shape. Adult trees are pruned 3 times a year. The 1st time is from late February to early March, after the fruit harvest is completed, cutting off overly dense branches, dead branches, water sprouts, or aged branches to promote new branch growth and favor fruiting. The 2nd time is around late May to early June. The 3rd time is about 20 days before Cold Dew. The 2nd and 3rd times are light pruning to keep the tree shape neat, ensure sufficient sunlight, improve air circulation, and reduce the occurrence of pests and diseases.

There are the following 3 methods for carambola pruning and training:

1. Natural round-headed type: prune carambola branches according to the tree's natural form.

2. Inverted cone type: this method is currently more commonly adopted in production areas, but according to different growers' views, there are two types: 45-degree trellis type and less than 45-degree trellis type, among which the 45-60 degree inclined type is better. With less than 45 degrees, the fruit is easily scratched and the economic value is low.

3. Simple inverted cone type: this method remedies the shortcomings that occur in adult trees of the natural round-headed type and is a method of changing from the natural round-headed type to the inverted cone type. First, after measuring the height of the horizontal trellis, cut off the branches 30 cm below the fixed position at the top of the trellis, retain the surrounding medium and small branches, and then build the trellis. Finally, pull the retained surrounding medium and small branches onto the trellis to allow the carambola to grow.

2. Intertillage and weeding. When carambola is first planted, because the space is relatively large, weeds grow easily, so manual weeding can be used. If herbicide is used, it must not be close to around the trunk or sprayed onto the leaves. Permeable chemicals also must not be used, so as not to damage the carambola roots. If the carambola planting site has been used for more than 2 years, the soil becomes hard. In order to make the soil well aerated, promote vigorous growth of fibrous roots, and make it easy for the plant to absorb water and nutrients, intertillage should be done 1-2 times a year, but not too close to the main trunk. Usually in early spring after fruit harvest and before the 1st pruning, it is carried out together with the application of manure compost. A depth of 6-7 cm is appropriate.

3. Fertilization. Pay attention to supplementing organic matter fertilizer in winter. Chemical fertilizers may be appropriately applied as topdressing before flowering or after fruiting. Among the three major elements, phosphorus and potassium fertilizers are primary, and nitrogen fertilizer is secondary. The amount of fertilizer applied depends on the leaf color of the plant and the fertility or poorness of the soil. Generally, the three major elements are combined in a ratio of 11:9:18, and the annual application amount per individual plant is as follows: 1-year-old -- 0.6 kg; 2-year-old -- 1.8 kg; 3-year-old -- 3.0 kg; 4-year-old -- 3.5 kg. The application period is from February to November each year, applied evenly in 6 applications. For young trees, ring or strip fertilization methods are used. For large trees, strip, spot, or broadcast fertilization methods are used. During this period, in order to increase soil organic matter and enlarge the fruit, slow-release fertilizers can be applied together. Apply 20-50 kg per plant each year, depending on tree age.