Causes and Countermeasures of low Fruit setting rate of Apricot

Apricot (scientific name: Armeniaca vulgaris Lam.) Deciduous trees, terrestrial, plants glabrous. Leaves alternate, broadly ovate or ovoid, margin obtusely serrate; flowers solitary, white or reddish; fruit subglobose, mostly white, yellow to yellowish red, often flushed; seeds bitter or sweet. The flowering period is from March to April and the fruiting period is from June to July. There is a lot of cultivation in all parts of China.

Factors affecting fruit setting of apricot trees

1. Pollination tree configuration factor. At present, most apricot varieties in China do not bear fruit, but some farmers just ignore this important phenomenon when developing apricot trees. When building a garden, planting a single variety or pollination trees is improper, often flowers but not fruit, low yield or no harvest year after year. The survey found that when building apricot orchards, a considerable number of farmers only pay attention to the introduction and development of new varieties, and do not understand or do not pay enough attention to the configuration of pollination trees. although some pollination trees are configured, the number of pollination trees is too small, accounting for only 1% of the total. 3% of the total, and the planting method is not scientific, can not be better pollination, directly leading to more apricot flowering, less fruit setting, low yield.

2. Fertilizer and water factor. Adequate supply of inorganic and organic fertilizers is the basis of high yield of apricot trees. At present, most apricot orchards are not only seriously deficient in phosphorus, potassium and other trace elements, but also far from being able to meet the needs of apricot growth and fruit. Some apricot trees even do not apply fertilizer for many years, resulting in lack of nutrition, weak growth, extremely low content of organic matter in the body, low physiological function, unable to blossom and bear fruit normally, resulting in many flower buds, large number of flowers and less fruit. Apricot trees are relatively drought-resistant and do not need to be watered in general, but if they are not watered in time under the condition of drought, it will cause serious flower and physiological fruit drop.

3. Pruning factor. Apricot is a light-loving tree species, only under the condition of sufficient light, can it grow and bear good fruit. Some apricot trees are in a post-release state and cannot be pruned, while some are improperly pruned, resulting in long branches and closed canopies, increasing the number of degraded flowers and affecting fruit setting. There are also some apricot trees with unreasonable branches when pruning, improper space and length of branches, etc., which also lead to flower and fruit drop.

4. Climatic factors. Although apricot trees are hardy, flowers and young fruits are often harmed by late frost, resulting in reduced production or even no harvest. This is the main reason why "apricot trees are full of flowers and fruits are sparse". The degree of freezing injury is related to the strength and duration of low temperature. The critical temperature of freezing injury to flowers and young fruits of apricot trees is-3.9 ℃ at early flowering stage,-2.2 ℃ at full flowering stage and-0.6 ℃ at young fruit stage. Therefore, anti-freezing and anti-freezing at flowering stage are important measures to be taken to develop apricot production, increase yield and increase income in some areas.

Technical measures to improve the fruit setting rate of apricot trees

First, select excellent varieties. Selecting the varieties with high complete flower ratio, strong self-fruiting ability, frost resistance, late flowering, early fruit and high yield as the main varieties is the key to improve the fruit setting rate. For example, Golden Sun, Kate Apricot and so on. In addition, early, middle and late maturing varieties can also be selected to reduce the loss caused by early spring frost.

Second, configure pollination trees. Varieties can not be too single, some varieties are self-fertile, need to be equipped with 2-3 varieties for pollination. The ratio of pollination trees to main varieties should be 1:3-4.

Third, strengthening the management of soil, fertilizer and water, strengthening the tree potential, increasing the accumulation of tree nutrients and improving the quality of flower buds are effective measures to reduce flower organ abortion, increase fruit setting rate and increase yield.

The base fertilizer should be applied in autumn, and it should be applied as soon as possible from September to October combined with hole expansion. In the young tree period, the whole garden should be turned over once in 3-4 years. When turning deeply, try to reduce the damage to the root, especially the backbone root. The base fertilizer is mainly stable manure, compost, human feces and urine, and the amount of fertilizer should be flexibly controlled according to tree age, tree potential, fruit yield and types of fertilizer.

On the basis of applying base fertilizer in autumn, topdressing fertilizer should be applied timely: before ⑴ sprouting (from late March to early April), urea 15kg / mu + N, P, K compound fertilizer 450kg / mu, hole application or furrow application, and the growing period of new shoots and flower bud differentiation period of apricot trees in mid-late May were the critical period of apricot fertilizer requirement. The fruit trees were topdressing urea 100-1205 kg / mu, ring spreading or furrow application, ⑶ fruits were topdressing with compound fertilizer dominated by nitrogen fertilizer, fruit trees were topdressing with N, P, K compound fertilizer 0.5kg / plant.

In order to supplement the nutrient consumption of the tree in time, it is necessary to fertilize the apricot outside the root. ⑴ sprayed the branches with 0.5-1% urea solution before flowering. ⑵ sprayed 0.3% borax and 0.3% urea solution at full bloom to increase the fruit setting rate. ⑶ sprays 0.3% urea + 0.3% potassium dihydrogen phosphate solution after flowering. Spraying 10 × 10-4B9 40 days after flowering in ⑷ could increase the first class flower ratio and fruit setting rate. ⑸ fruits were sprayed with 0.3-0.4% potassium dihydrogen phosphate in the first half of ripening to promote fruit coloring.

4. releasing bees and artificial pollination in flowering orchards. Apricot trees are insect-pollinated flowers, and bees and other insects can help pollinate. Putting bees in the apricot orchard can obviously increase the fruit setting rate. Due to the short flowering period of apricot, in case of low temperature, cloudy weather, rainfall or strong wind and other adverse weather, insect activity is blocked, it will affect pollination, so it is necessary to carry out artificial pollination. Artificial pollination uses the pollen of mountain apricot (large pollen quantity and strong pollen viability). The pollen and starch are mixed at 1:2 and then dipped in the rubber head of a brush or pencil and placed on the stigma of the flower.

5. Delay flowering and avoid frost. Because apricot trees are vulnerable to late frost at flowering stage, the fruit setting rate is low. To this end, we adopt: ⑴ trunk whitening plus spraying 8% lime water in the crown or repeated irrigation in early spring to reduce soil temperature, delay germination, and delay flowering by irrigation before flowering. ⑵ full bloom frost can be sprayed 350x before the arrival of frost, or flowering spray water (water freezes, to release heat) or smoke measures to prevent frost. When frost weather is predicted, the smoke pile is lit at 2: 00 at night, so that the temperature of the apricot orchard will not drop below zero. ⑶ re-pruning. Some varieties (such as red purse) in summer re-pruning can promote secondary branches, secondary branches grow to 30 cm after coring can promote three branches, or even four branches, so that the florescence of the first, second, third and fourth branches can be prolonged by 5-7 days, even after the first batch of jelly, the flowers on the second, third and fourth branches can avoid the late frost and greatly improve the fruit setting rate.

6. Girdling of young trees. The suitable period for ring peeling is in the middle of May. The width of the main ring peeling mouth is 25-1 stroke 30 of the thickness of the dry diameter. The peeling mouth is smeared with 25% carbendazim 100 times solution and bandaged with plastic film (which can effectively reduce glue flow and promote wound healing). One week after peeling, 0.3% urea solution was sprayed twice, once a week, and then 0.3% potassium dihydrogen phosphate solution was sprayed twice, each time at an interval of one week. Girdling can effectively increase the flower yield and fruit setting rate of young trees in the following year.