In the season of yellow peaches on the market, the cash crop expert group of the Heshan District Science and Technology Expert Service Group of Yiyang City, and the team of Wang Dixuan, the rural science and technology commissioner of Yiyang City, have received several fruit farmers to report that most of the early-maturing yellow peaches they planted are sour, looking at the yellow peaches hanging on the tree, they can't be sold, I don't know what the reason is, is there a good way to make the yellow peaches on the tree sweet, and consult with cyclamate to improve the taste is it effective?
Judging from the ** sent by the fruit farmers, I saw that the small yellow peaches were densely hung with branches, and the fruiting branches were also bent, obviously too many fruits were the main reason for the sourness of yellow peaches, and some fruit farmers reported that the sourness of yellow peaches was mainly due to the lack of fertilization in the winter of 2022 and the entire growth period in 2023. In addition, too dense branches and leaves, not properly pruned, and poor coloring of yellow peaches will also cause yellow peaches to be sour. As for cyclamate, it is actually a foliar fertilizer, which has a certain improvement effect, but it has little effect on spraying in the later stage of fruiting and near the harvest period. In view of the frequent occurrence of yellow peach sourness, the author systematically summarizes the causes of this phenomenon and the prevention methods, so as to facilitate the prevention of the consequences in advance.
Figure Fruit set is too much and fruit is not thinned.
1. Possible causes of peach sourness.
1 Possible causes of peach sourness.
1.1. The planting density and shaping pruning are not reasonable.
The planting density is too large and the management technology is not matched, which can easily lead to large branches in the canopy and canopy closure, insufficient light of the fruit, poor coloration, small fruit, low sugar content and poor fruit quality. Shaping and pruning is not carried out according to the characteristics of the variety, the age of the tree, the vigor of the tree and the cultivation conditions.
1.2 Leaving too much fruit.
Some fruit farmers blindly pursue yield, and do not carry out plant adjustments such as thinning flowers and fruits, resulting in small fruits, poor coloring, and light flavor.
1.3. Unreasonable fertilizer application.
Some fruit farmers neglect management, do not apply fertilizer in time, and in the case of more fruit set, insufficient fertilizer leads to small fruit and stunted growth. There are also chemical fertilizer application rates that are too large, especially nitrogen fertilizers, which make the fruit flavor lighter. The application of large amounts of chemical fertilizers can damage the soil structure, lead to soil acidification and compaction, reduce the beneficial microorganisms in the soil, imbalance the proportion of nutrients in the soil, and aggravate soil-borne diseases. Less application of organic fertilizer and lack of medium and trace elements lead to poor plant growth. Excessive application of chemical fertilizers destroys the soil system, creating a vicious cycle that causes peach trees to become too dependent on chemical fertilizers. Some often pay attention to nitrogen and phosphorus fertilizers, especially nitrogen fertilizers, and ignore the application of potassium fertilizers, resulting in low yield and poor quality.
1.4. Insufficient soil organic matter.
In most peach orchards, the soil organic matter content was less than 1 or close to 1, and the amount of organic fertilizer was reduced, and soil weeding or chemical herbicides were mostly used. Long-term application of a large amount of chemical fertilizer, so that the physical and chemical properties of the soil deteriorate, the fertilizer utilization rate is low, the fertilizer and water retention capacity is poor, and the physiological diseases of trees and fruits are becoming more and more serious.
1.5. Excessive watering or precipitation during the ripening period of the fruit.
Watering several times during the ripening period can promote the growth of the fruit, but the quality of the fruit will deteriorate. Heavy rain during the ripening period will aggravate the occurrence of fruit diseases, and at the same time, the rain will also reduce the content of soluble solids in the fruit, affecting the quality of the fruit.
Second, the way to prevent peach sourness.
2.1. Reasonable dense planting.
The peach tree has strong photophilicity, sufficient light, strong tree, fully developed branches, and full flower buds. Therefore, it is necessary to choose a reasonable planting density, wide row dense planting cultivation is the development trend of yellow peach, and the general plant row spacing can be used for open field cultivation (15~2.0) m (4 5) m. Good tree shape, tree body ventilation and light transmission conditions are the basis for the comprehensive coloring of fruits. The "Y" shape (Fig. 4), which is currently popularized in production, is conducive to the coloring of yellow peaches.
Figure Y-shaped tree shape is good for peach coloring.
2.2 Trim in time.
2.2.1 Reasonable winter pruning Winter pruning is mainly to adjust the position, number and distribution of fruiting branches, in order to maintain the balance between the ground and the root system, the amount of flowers and the tree potential, when winter pruning, to remove the upright branches, long branches, turning branches, diseased branches and over-dense branches, the rest of the branches and long branches are pruned, and the excess development branches are thinned or truncated. For erect branches, if the branches are dense in the remaining position, they are thinned from the base; If there is space in the location, carry out extremely heavy stubbing, promote branching, cultivate into fruiting branches, and at the same time thin out diseased branches, cross branches, weak branches, etc.
2.2.2 Wipe the buds in time After germination in spring, wipe off the double-bud branches and dense branches in time.
2.2.3 Timely summer pruning Summer pruning is good for promoting the fullness of the branches and the formation of full flower buds. Remove too many new shoots so that the base of the ipsilateral shoots is spaced about 20 cm apart. Oblique branches and lateral branches should be controlled to grow, erect long branches should be thinned in time, and the rest of the new shoots should grow slowly.
Through pruning, ensure that the tree body is ventilated and transmitted, the tree body grows in a balanced manner, and the upright and long branches are treated in a timely manner, and the branches that affect the coloring of the fruit are thinned. A few days before picking the bag, remove the shading leaves around the fruit, lay reflective film on the ground, and hang or support the drooping main side branches and large and medium-sized fruiting branches to improve the coloring and sugar content of the fruit, reduce the acidity, and improve the quality of the fruit.
2.3 Apply fertilizer at the right time.
The basal fertilizer should be applied early rather than late, and the best effect is applied in autumn (especially in early autumn from September to October). The base fertilizer is mainly fully decomposed farmhouse fertilizer, sheep manure and rabbit manure are better, generally 4000 5000 kg per mu, there is no farm fertilizer, you can also use 400 500 kg of commercial organic fertilizer instead, or apply biological bacteria type organic fertilizer (containing Bacillus subtilis, Bacillus megamegalosporus, amino acids, organic matter content 45, nitrogen, phosphorus and potassium content 6) 8 kg, and then apply an appropriate amount of yellow peach special compound fertilizer (or potassium sulfate compound fertilizer) and trace element fertilizer (superphosphate, borax, ferrous sulfate, zinc sulfate, manganese sulfate, etc.). Fertilization depth 30-50 cm. Methods such as annular ditch application, radial ditch application, strip application and whole garden general application can be adopted. Do not apply ground and compacted fertilization. The period of top dressing mainly includes several key periods such as pre-flowering, post-flowering, hard core period, and fruit expansion period.
Figure Organic fertilizer applied to peach trees.
Pre-flowering fertilizer, applied after the soil thaws to before flowering, generally in early and mid-March, 2 to 3 weeks before germination, mainly fast-acting nitrogen fertilizer (15 25 kg of urea per mu), with an appropriate amount of phosphorus and boron fertilizer. or post-flowering fertilizer, which is applied after the end of flowering, mainly with fast-acting nitrogen fertilizer, combined with the application of phosphorus, potassium and boron fertilizer.
The hard core period of the fruit, generally from late May to early June, is applied at the beginning of nuclear hardening, mainly potassium fertilizer, with the application of nitrogen, phosphorus and calcium fertilizer, and 50 60 kg of ternary compound fertilizer per mu, pay attention to supplementing silicon fertilizer.
Puffy fruit fertilizer, 20 30 days before maturity, mainly nitrogen and potassium fertilizer, 10 15 kg of urea and potassium sulfate per mu, and 15 kg of magnesium fertilizer such as magnesium sulfate or high potassium compound fertilizer (15-5-26) are applied with foliar spraying.
Extra-root topdressing is a method of auxiliary soil fertilization, nitrogen fertilizer mainly includes urea, ammonium nitrate, ammonium sulfate, etc., with urea being the most widely used. Phosphate fertilizers include ammonium phosphate, potassium dihydrogen phosphate, and superphosphate. Potash fertilizers include potassium sulfate, potassium chloride, potassium dihydrogen phosphate, etc., with potassium dihydrogen phosphate being the most widely used. Trace element fertilizers include borax, boric acid, ferrous sulfate, manganese sulfate and zinc sulfate, etc., or strong cyclamate (potassium, calcium, boron, magnesium and other trace elements and plant proteases, a variety of vitamins for organic synthesis, so that all inorganic components are organic, and plants can be automatically absorbed), peach sweetening and expanding Liangguo and other trace element water-soluble fertilizers, which can be sprayed before 10 o'clock or after 16 o'clock on a cloudy, windless or breezy sunny day, and keep it 12 hours after spraying.
2.4. Reasonable irrigation.
Peach trees are sensitive to water, drought tolerant and waterlogging, but they still need to supply sufficient water from germination to fruit ripening, and suitable soil moisture is conducive to flowering, fruit setting, germination of new shoots, flower bud differentiation, fruit growth and quality improvement. Soil moisture content should be between 60 and 80 throughout the growing season. The critical period for water requirement is before flowering and at the end of fruit expansion (20-30 days before harvest). If the soil is dry during the final expansion period of the fruit, it will affect the expansion of the fruit cell volume, reducing the fruit mass and volume. However, reduce the amount of irrigation or stop irrigation 20 days before harvest to increase the sugar content of the fruit and promote the formation and coloration of anthocyanins.
2.5 Grass cultivation.
Grass in peach orchard is conducive to improving fruit quality, reducing nitrogen content in soil, increasing the effective content of phosphorus and calcium, making peach trees nutritionally balanced, leaf hypertrophy, flower buds increased, and fruit setting rate high. It can increase the content of soluble solids and fruit hardness in fruits, promote fruit coloration, improve fruit disease resistance and storage resistance, reduce physiological diseases, and clean fruit surface. Green grasses, such as white clover, alfalfa, milk vetch, rat thatch, etc., are planted between the rows of peach orchards, and they are mowed and covered between the rows of trees in a timely manner, and turned into the soil after decay to increase the content of soil organic matter, but weeds should not be bred in the tree trays, which can improve the microecological environment of peach orchards.
Figure: Grass cultivation and cultivation of milk vetch in peach orchards.
2.6. Reasonable fruit retention.
The peach tree has a large amount of flowers, almost more than 10 times the amount required, only about 10 fruits can be kept to meet the production needs, the growth of the fruit depends on the accumulation of nutrients in the tree, the more the number of fruits, the smaller the size. Therefore, according to the characteristics of the variety, the condition of the tree and the management level, the flowers and fruits should be thinned in time, so that the tree body can be reasonably loaded, the fruit volume can be increased, and the commercial fruit rate should be improved.
2.6.1 Thinning buds Peach sparse flowers and fruits can save nutrients stored in the tree and promote the early development of fruits, so the earlier the better. The budding effect is best when the flowers are yellow. The flower buds and leaf buds on the back of all the long, medium and short fruit branches are thinned together, which can also prevent the occurrence of dorsal branches. The flower buds at the top and base of the long and medium fruit branches are not well developed, and the fruit quality is not good, so they should also be thinned. Finally, the long and medium fruit branches leave 5 15 bud positions in the middle of the branches, and the short fruit branches and bouquet-shaped fruit branches only leave 1 2 bud positions at the top. That is, one developed flower bud is left every 15 cm in the middle and front of the branch, and the final amount is about 3 times the number of fruit sets. Varieties with less pollen should be left in abundance.
2.6.2 Flower thinning Flower thinning is carried out after bud thinning, and the method is the same as bud thinning. For those who are missing when thinning the buds, they should be filled. In addition, for each bud position left, only one of the best-developed flowers is left, and the rest of the flowers are all thinned. However, for varieties that are susceptible to frost damage and varieties that are susceptible to adverse weather such as late frost, sandstorms, and rain, flowers are generally not thinned. For pollen-free varieties, flower thinning is not performed. Only varieties with a high fruit set rate are thinned.
2.6.3 Fruit thinning can increase the quality of a single fruit, improve the external quality of the fruit (peel color, fruit color and fruit shape, etc.), and can also improve the internal quality, such as soluble solid content, aroma, nutrients and edible rate, etc., which should be carried out according to the tree potential and the growth of new shoots and young fruits. Peach fruit thinning is easy to cause physiological fruit drop and fruit cracking at one time, so it should be carried out in stages.
The first is the preparatory fruit thinning period, which is usually carried out about 3 weeks after flowering, and the amount of fruit left is 15 2 times. 20 days after flowering, it is easy to distinguish between fertilized and unfertilized fruits. The fertilized fruit is enlarged, the sepals are atrophied and detached from the base; Unfertilized fruits, sepals remaining and hypertrophied, should be completely thinned.
The second is to complete the fruit thinning period, which is carried out about 7 weeks after flowering and ends before the hard core stage, and the deformed fruits and diseased fruits are removed at any time. Generally, strong trees should be thinned late, and weak trees should be thinned early. The fruit thinning should be carried out according to the distribution of the amount of fruit left in different parts of the tree. Thin out the short round fruit, keep the oblong fruit, and leave one for the fruit, and remove the small fruit, yellow fruit, deformed fruit, and diseased fruit. The upper, middle and lower parts of the canopy are adjusted so that all the fruits are basically the same size. After the completion of the fruit thinning period, the normal fruit and the double embryo fruit can be distinguished, usually there is 1 embryo in the nucleus, the double embryo fruit has 2 embryos, the proportion of growth on both sides of the suture line of the normal fruit is 6 4, and the double embryo fruit is 5 5, and it is easy to physiologically drop the fruit, so it should be thinned as soon as possible.
The third is to correct the fruit thinning period, which is carried out before the peach fruit bagging, mainly to remove deformed fruits and diseased and insect fruits.
After three fruit thinnings, the final amount of fruit remains: 3 5 fruits (3 for large and medium-sized fruits, 4 5 for small fruits) on long fruit branches (about 30 cm) near the branches**, 1 3 fruits for medium and medium fruit branches (about 2 for large and medium-sized fruits, 2 3 for small fruits) on the middle and front end of the branches, 1 fruit or no fruit for short fruit branches (15 cm) (1 fruit for 2 3 fruit branches for large and medium-sized fruits, 1 fruit for every 1 2 branches for small fruits). It is also possible to leave the fruit according to the fruit spacing, which is 15 to 25 cm, depending on the size of the fruit. In addition, it is also necessary to grasp that the fruiting branches in the upper part of the tree body should leave more fruits, and the fruiting branches in the lower part should leave less fruits; Trees with strong strength leave more fruits, and trees with weak trees leave less fruits; When there are fewer branches on the uppermost part of the canopy and the dorsal trunk branches, there are as few fruits as possible.