How to adjust the size and year of citrus?

In production practice, the phenomenon of big and small years often appears in citrus orchards. The analysis and demonstration results of field management experiments for many years show that there are two main reasons for the phenomenon of big and small years: one is production habits. Many fruit farmers don't have the habit of thinning fruits, no matter how many fruits they produce each year. There are too many fruits in the New Year, and fruits consume too much nutrition. Too little nutrition for flower bud differentiation leads to too few flower buds. In the second year, due to the small number of flowers, the vicious circle continued. The second is the climate. Many citrus planting areas in China will encounter severe frost every once in a while, ranging from flower buds to citrus trees. After the flower buds freeze to death, they form a small year. In the small year, there are few fruits and too many nutrients, resulting in too many flower buds, and the next year they form a super-large year.

So, how to solve the problem of citrus age? We believe that the corresponding technical measures can be effectively adjusted and solved in the four periods of citrus growth and development every year.

first stage

Pruning before sprouting after beginning of spring.

In winter, the temperature is low, the air humidity is low, and the sap stops running relatively. Pruning in winter will increase the number of dry branches, so pruning in winter is not suitable. The best pruning time before germination is from beginning of spring to early spring. The principle of pruning is "one year heavy pruning, one young pruning".

The pruning of New Year's trees refers to the early spring pruning from picking fruit in the next year to budding in the new year. The pruning goal of annual trees is to reduce the yield of annual trees, increase the proportion of vegetative branches and improve the small annual output in the coming year by moderately reducing the amount of flowers. Trees in the New Year must be pruned again, and the fruiting branches should be shortened to reduce the fruiting, so as to promote more nutritious branches in the spring shoots. The number of truncated fruiting mother branches depends on the severity of annual phenomenon and the climate of flower bud differentiation. If the phenomenon of big and small years is serious, cut it short, otherwise it will be reduced. In the flower bud differentiation period (10-165438+10 month), the pruning should be appropriately increased in the years with more sunshine and less rainfall, otherwise the pruning should be reduced. When cutting the mother branch, the branch tips should be evenly selected in all parts of the crown for short cutting, so that they are evenly distributed around the crown. Sparse leafless branches, cross branches, weak branches, over-dense branches, pest branches and branchlets, but the bearing mother branches should be kept in all parts.

Pruning of off-year trees refers to pruning of off-year fruits after they are picked and before they sprout in early spring. Small trees must be cut lightly. The pruning goal of young trees is to keep flowers as much as possible, let them blossom and bear fruit, and reduce the number of vegetative branches appropriately. Do not move the fruiting branches, and focus on thinning or cutting down the drooping branches and inner cavity branches to make the branches distribute reasonably.

The second period

Prune 5-20 days before flowering. In the new year, the principle of "heavy pruning every year" will be implemented, and leafless flowers will be cut off, leafy flowers will be cut short, and flowers that are too dense will be thinned out to achieve a reasonable amount of flowers. The degree of cutting of leafy branches is determined by the amount of flowers. If the flower amount is too large, it should be cut again, and 1/2- 1/3 on the upper part of the branch should be cut off. If the flower amount is too large, cut it lightly, and cut off1/4-1/5 at the upper part of the branch; The flowers are not short. Pay close attention to the protection of young flowers and minimize the loss of flowers.

tertiary

In the young fruit stage, if there are too many fruits, the deformed fruits and some surplus young fruits should be thinned (leaving room), and the fruit thinning should be completed before entering the fruit expansion stage to achieve a reasonable yield (2250- 2500 kg per mu); If the results are few, we should pay close attention to fruit preservation. We can use (1g 92O with 50 kg of water+1G2, 4- D with 20 kg of water+1000 times 21kloc-0/6+to gird the trunk) to preserve fruit, so as to minimize physiological fruit drop.

The fourth stage

During the flower bud differentiation period from June 65438+ 10 to early February. In case of Spring Festival, spray flower promoter (such as 400-fold paclobutrazol and 300-fold patented PBO)+ potash fertilizer (0.2% potassium dihydrogen phosphate, 0.2% potassium sulfate, etc. )+New Year's Day 65438+1October-65438+1October; In case of off-year, 92o should be sprayed after the off-year fruits are picked and before 65438+February 10. The dosage of 92o should be sprayed with different concentrations according to the severity of off-year phenomenon. In case of off-year phenomenon, add 1.5-2g of 92o for every15kg of water, and15kg of water for less serious cases.

Dan Ling County Agriculture Bureau Duojing Station Chen

[Related background]

Dan Ling county is located at the southwest end of western Sichuan plain, with an average elevation of 480m, annual average temperature 16.8 degrees, annual minimum temperature 1 to -2 degrees, annual minimum temperature -4 degrees in recent 35 years, annual average total accumulated temperature of 6094 degrees, annual average rainfall1250.3mm and annual average sunshine hours/kloc. The soil in citrus planting area is mainly yellow soil, and the soil PH value is 5-7. There are navel oranges, mixed oranges, tangerines, tangerines and blood oranges in the county, covering an area of nearly 90,000 mu, with an annual output of more than 60,000 tons of various citrus fruits.

Source: Sichuan Rural Daily