Cultivation techniques of carambola in Singapore

Singapore carambola is one of the most excellent varieties in carambola cultivation at present. it has large fruit, single fruit weighs more than 280g, fruit shape is correct, fruit color is bright yellow, fruit edge is thick, flesh is crisp and brittle dregs, fruit core is small, seeds are few or none, edible rate is high, juice is more clear and sweet, soluble solids content is more than 10%. This variety has the advantages of fast growth, early fruit, high and stable yield, and stronger adaptability than other varieties. Due to the excellent quality and storability of carambola in Singapore, the price of carambola is 2-3 times higher than that of ordinary carambola. At present, the price of commercial fruit in orchards with good cultivation and management conditions can be as high as 24 yuan per kilogram, and the economic benefit is high.

I. Establishment of a garden and planting

Singapore carambola is a tropical evergreen fruit tree, which is hot and humid, shade-tolerant, cold-shy, afraid of drought and wind. Therefore, in a suitable cultivation area, flat land with deep and fertile soil, adequate water sources, convenient drainage and leeward to the south or southeast should be selected to build a garden. If the garden is built in the mountainous area, it is appropriate to choose the southward or southeastward sloping land with irrigated water, good soil quality and small slope. The construction of flat land garden generally requires the excavation of drainage and irrigation ditches, the depth should be determined according to the level of groundwater level, and should be excavated and improved year by year.

Planting specifications can be divided into three ways: 3m × 4m, 3m × 5m or 4m × 4m. Large planting holes should be dug before planting and sufficient rotten organic matter fertilizer should be applied as base fertilizer. The planting holes in the flat orchard are 50 cm deep and 50 cm wide, while those with poor soil quality can be deepened and widened appropriately; the planting holes in the mountain orchard are 1 meter deep and 1 meter wide, and the holes need to be enlarged year by year after planting.

As the carambola trunk is afraid of the sun, it is appropriate to wrap the trunk with straw until the trunk can be shaded by the crown.

II. Shaping and pruning

The main results are as follows: 1 early young tree shaping: the main goal is to cultivate a round crown with compact structure. After the young trees were planted, the tops were cut at 40cm to 50cm above the ground, and 3 or 4 main branches with uniform distribution were left after shooting. when the main branches were 30cm and 40cm long, each branch had 2 or 3 buds. Because carambola had strong ability to shoot and branch, it was used as a principle for shaping. With the increase of the number of branches, a high-yield crown could be formed by spring planting to the end of the next year. In the process of shaping, the thin and weak branches can be fixed with bamboo branches or string to prevent sagging, and the main branches can be evenly distributed.

2 pruning during the fruiting period: at this time, the pruning should be light rather than heavy, and the middle and lower branches should be retained as far as possible, so that they are arranged in layers, branches and leaves are evenly distributed, and the density is moderate. For young and middle-aged fruiting trees, it is appropriate to remove overlord branches, remove some vegetative branches in the upper part of the crown to inhibit growth, and pay attention to cutting thumb thick branches in different directions year by year, so as to maintain strong tree momentum and ensure annual yield. For the old and weak trees, the upper branches of the crown can be cultivated to shade the trunk, and the overgrown branches can be fully used to fill the gap in the crown and renew the old branches. When pruning the branches (bore branches) in the carambola crown, the branch stump of 1 cm to 2 cm can be left to bear branch fruit and increase the yield of the same year. Since carambola can usually shoot 5-6 times a year, the pruning period can be arranged in March-April, June-July and September-October, mainly to cut off overgrown branches, disease and insect branches, overdense cross branches, thin and weak branches and short overcut drooping branches.

In addition, Singapore carambola has more flowering and high fruit setting rate under normal cultivation and management. if it is allowed to bear fruit naturally, it is easy to lead to small fruit, affecting fruit quality, flavor and tree potential, thus affecting the yield of the next and even next year. Therefore, it should be moderate thinning of flowers and fruit.

III. Fertilization

1 Base fertilizer: the base fertilizer of newly planted fruit trees is applied during burrowing, with 10-15 kg of rotten livestock manure, 1 kg of gluten fertilizer and 1 kg of superphosphate in each hole. The base fertilizer should be mixed with the soil and backfilled, and then the topsoil should be filled back, and it should be 20 cm above the ground to prevent stagnant water. The fruit trees can be applied in December every year or after the last fruit pruning. Each tree is applied with 1520kg of rotten livestock manure, 1.5kg of gluten fertilizer and 1.5kg of calcium superphosphate, and a circular ditch is dug around the crown drip line. In the future, with the increase of tree age and fruit amount, the amount of base fertilizer should be increased appropriately.

(2) topdressing: young trees began to apply thin manure from the end of February to the beginning of March, once a month, and the plant grew slowly after November, and stopped applying fast-acting fertilizer. About 10 kg of rotten livestock manure or soil fertilizer was applied to each plant before and after "the Winter Solstice". Hole application was used to enhance the tree potential and improve the cold resistance of the tree.

The fruit trees are generally fertilized 4 times for each fruit, taking the first fruit as an example:

(1) Fertilizer for promoting shoots, strong shoots and flowers should be applied from March to April, with 0.2-0.3 kg compound fertilizer, 0.1 kg urea and 10-20 kg mature human and animal manure per plant.

(2) Fruit protection fertilizer, when the thumb size of fruit is being produced and the pedicel begins to sag from June to July, each plant is treated with rotten organic fertilizer (according to calcium superphosphate ∶ bran fertilizer ∶ human feces and urine = 1 ∶ 2 ∶ 100retting) 25kg 30kg

(3) Fertilizer for strengthening fruit and promoting flower should be applied in the period of rapid fruit expansion after August, and the species and quantity are the same as that of fruit protection fertilizer.

(4) ripening fertilizer should be applied before fruit ripening, and urea should be applied 10g to 20g per plant.

IV. Drainage and irrigation

Carambola absorption root distribution is shallow, easy to be affected by external conditions, so in the dry and high temperature season should be timely irrigation, covered with weeds to keep the soil moist, and reduce the soil temperature, in order to adapt to the normal growth of root system. Carambola roots are not resistant to flooding, which can lead to rotten roots, fallen leaves and fruit for a long time, so the drainage ditch should be dredged and the groundwater level should be lowered before the rainy season. Mountain orchards should expand holes and improve soil in time to prevent stagnant water.

Prevention and control of diseases and insect pests

Singapore carambola has fewer diseases and insect pests, and the main diseases are anthracnose and red spot. 0.5%-1% Bordeaux solution is commonly sprayed 2 times 3 times, once every 7-10 days; the main pests are bird feather moth, black-spotted brown leaf moth and fruit fly. 90% trichlorfon 800 times solution is commonly used. Bagging carambola fruit with thumb size can effectively prevent the harm of fruit flies, prevent mechanical injury, improve fruit quality and increase commodity value.