How to manage citrus in winter? Experts teach you the core points covering these five aspects.

For citrus, winter is a key point in the annual management of citrus orchards. At this time, the management method, quality and level not only directly determine the yield and fruit quality of the orchard in that year, but also directly affect the strength of the tree, wintering cold resistance, the differentiation of citrus flower buds, the flowering and fruiting of the orchard in the next year, the number of overwintering pests and diseases, and the occurrence of fruit tree pests and diseases in the next year.

Therefore, the comprehensive and scientific winter management of citrus orchards is the key to cultivate strong trees, harvest year after year, avoid freezing injury in winter and prevent diseases and pests in orchards.

So, what aspects should we fruit farmers comprehensively control citrus in winter? What problems should be paid attention to in various management and how to operate them? Today, I will give you a comprehensive introduction from the following seven aspects!

First, do a good job in the management of citrus harvest period and the prevention and control measures of fruit cracking and falling before harvest

1, citrus pre-harvest management

For mid-late ripening citrus orchards, in order to prevent falling flowers and fruits and improve the yield and quality of fruit picking, the following points should be paid attention to before harvesting:

On the one hand, for large fruit setting, we should pay attention to reasonably controlling the number of fruit setting according to the tree potential to prevent citrus from being weak and cold-resistant due to excessive fruit setting and excessive nutrient consumption;

On the one hand, proper water control should be carried out in time about two weeks before citrus harvest, and nitrogen fertilizer should be avoided during the harvest period to promote better coloring, ripening, weight gain and sweetness of citrus fruits, and at the same time prevent the fruits from turning green, sprouting new shoots, cracking and rotting.

On the other hand, before harvesting citrus fruits in winter, we should pay attention to check the weather forecast for the next 3-5 days and 10- 15 days every day, and do a good job in the cold and antifreeze management of citrus in advance according to the weather changes. If necessary and possible, the method of capping and bagging fruits can be adopted to prevent freezing injury at low temperature.

In addition, in order to make the citrus fruit color better, mature, sweet and gain weight before harvesting, we can manage it by spraying potassium dihydrogen phosphate on the crown (prochloraz can be used one month before harvesting), laying reflective films on the ground and pulling branches to support the fruit.

2. Citrus harvest management

The harvest of citrus should be carried out in time and reasonably. Generally speaking, citrus fruits can be harvested in time when the fruit surface turns from green to yellow and the fruit becomes soft and hard. If the citrus fruit is harvested too late, it will not only increase the consumption burden of nutrients in the tree, but also easily cause freezing damage and reduce the quality of the fruit when the cold current comes.

When citrus is harvested after maturity, on the one hand, we should pay attention to avoid rainy days, and when it rains, we should harvest it after 1-2 days to prevent the fruit from rotting or insufficient sugar content after harvest;

On the other hand, it is suggested to adopt the double cutting method of "round head" and "one fruit is cut twice" when picking fruits (first, cut off the fruit with three leaves from the tree and trim the top of the bearing branches at the same time; Second cutting: cut the fruit from the fruit stalk) to avoid the fruit from being cut and prevent the fruit tree from sprouting spring bushes;

On the other hand, the fruit picking sequence should be carried out in batches and times according to the basic principle of "weak trees and weak branches first, strong trees and strong branches later, upper parts and lower parts first, and inner cavities of outer crowns of trees first". Early-maturing fruit trees can be picked first, and late-maturing fruits should be picked later. Generally speaking, it is most suitable for citrus fruit trees to be picked 2-3 times.

Using the above method to harvest citrus can not only maintain the vigorous growth of fruit trees, but also harvest more high-quality big fruits, which is also conducive to promoting the rejuvenation of trees as soon as possible and the full differentiation of flower buds.

3. The common causes and prevention methods of a large number of fruit drop before citrus harvest.

Many fruit farmers often encounter a lot of problems of fruit cracking and fruit dropping during the mature harvest period of citrus in winter. Here, the agricultural technology basket also gives you a brief explanation of the reasons and solutions. There are several common reasons for a large number of fruit cracks or fruit drops in citrus maturity:

① The reason of malnutrition is that the temperature of citrus is low from fruit expansion period to mature harvest period, and the root absorption capacity is poor. If the nutrient supply is insufficient at this time, a large number of aboveground leaves will compete fiercely with fruits for nutrients. Under the fierce competition for the advantages of branch tops, a large number of fruits on fruit trees will fall early because of insufficient nutrient supply.

In addition, excessive application of nitrogen fertilizer before harvesting, continuous low temperature weather and magnesium deficiency in fruit trees will also lead to citrus fruit dropping due to green shoots, late shoots and poor photosynthesis.

(2) The causes of excessive humidity include the long-term drought and water shortage or excessive water control in the orchard, which is not conducive to the absorption of calcium and causes the citrus fruit to crack and fall off; excessive precipitation or sudden heavy rain or flooding after a long-term drought from the late stage of fruit expansion to the mature stage of discoloration, which makes the water in the citrus fruit increase greatly, leading to the rapid expansion of pulp and the bursting and falling off of the slow-growing peel.

(3) Causes of low temperature weather: When the citrus enters the color-changing maturity, if the temperature drops suddenly or sharply, a large amount of ethylene and abscisic acid will be formed in the fruit, which will separate the fruit stalk from the fruit base, leading to the problem of early falling.

(4) The reason for the excessive fruit setting is that the excessive fruit setting will lead to the withering of the fruit.

⑤ Causes of diseases and insect pests: If serious diseases and insect pests such as anthracnose, brown rot, Fusarium wilt, Bactrocera dorsalis, Noctuidae, and peach moth occur in citrus, it will also cause premature fruit drop before fruit harvesting.

In the management measures to prevent early cracking or early falling of citrus fruits during the mature harvest period, it is suggested that you take the following measures for protection:

① Apply more phosphorus and potassium fertilizers, strictly control nitrogen fertilizers, properly apply microbial fertilizers during the fruit expansion period of citrus (especially fruit trees with weak tree potential and high fruit yield), and spray potassium dihydrogen phosphate and amino acid foliar fertilizers before the fruit is colored to the early stage of discoloration. For citrus fruit trees with serious fruit drop problem, it is suggested to spray foliar fertilizer containing prochloraz and other suitable plant growth regulators to enhance the stress resistance of citrus and improve the fruit retention rate of citrus.

(2) For citrus fruit trees with large fruit bearing capacity, drooping fruit and closed branches, on the basis of reasonably reducing the amount of fruit left, it is suggested to pull branches, hang branches and support fruits, so as to reduce the nutritional burden of the trees, improve the lighting conditions, enhance the ability of photosynthesis of leaves to make nutrients, and further alleviate the problem of citrus fruit dropping.

(3) Proper water and fertilizer control should be paid attention to when citrus enters the later stage of fruit expansion or before discoloration. In case of continuous rainfall, the whole garden should be sprayed with 1-2 times of bactericidal pesticides before and after the rainfall, but it is best to finish spraying about 1 month before fruit picking.

Two, comprehensively do a good job in citrus winter fertilization management.

Citrus winter fertilizer, also called base fertilizer, is also called citrus fruit picking fertilizer because it is applied during fruit picking.

Citrus winter fertilizer is the main nutrient source for citrus growth and development in the next year, and it is also the nutritional basis for promoting citrus flower bud differentiation, improving flower bud division and ensuring a bumper harvest in the next year.

Scientific and reasonable fertilization of citrus in winter can not only increase fruit yield and improve fruit quality, but also keep the tree vigorous, promote flower bud differentiation, enhance cold resistance in winter, and prevent late shoot growth and early fruit falling off.

1, citrus fertilization should be reasonable in winter.

When applying winter fertilizer to citrus fruit trees, it must be carried out according to the principle that decomposed organic fertilizer is the main fertilizer, supplemented by nitrogen, phosphorus and potassium fertilizer, supplemented by medium and trace element fertilizer and microbial bacterial fertilizer, so as to achieve the best effect of organic+inorganic, long-term+quick-acting, large and medium trace elements, strong trees+strong roots. However, attention should be paid to controlling the amount of nitrogen fertilizer, and the appropriate ratio of nitrogen, phosphorus and potassium fertilizer is 65,438+.

2. Fertilization of citrus in winter should be timely.

Generally speaking, young fruit trees that do not bear fruit in the second year can be applied with winter fertilizer before the low temperature from June 65438+February to June 65438+1October, and young fruit trees that bear fruit in the second year are recommended to be applied before the winter of June 65438+February.

It is suggested that winter fertilizer should be applied to citrus varieties with middle and early maturity immediately after fruit picking.

The time of topdressing winter fertilizer for mid-late maturity citrus varieties should be combined with the strength of tree potential and fruit yield. For fruit trees with weak trees and high fruit yield, winter fertilizer should be applied 7 days before fruit picking, and for fruit trees with strong trees, winter fertilizer can be applied less or even not after fruit picking. Late-maturing varieties should be applied winter fertilizer as soon as possible in autumn shoots.

In addition to grasping the fertilization time of citrus, we should also pay attention to grasping the optimal fertilization temperature. It is best to apply citrus winter fertilizer at the temperature above 10, but if winter fertilizer is combined with microbial fertilizer in orchard, it should be applied at the soil temperature above 15, because too low soil temperature is not conducive to the survival and reproduction of beneficial bacteria.

3, citrus winter fertilization should be appropriate.

Under normal circumstances, the amount of fertilizer applied in winter during citrus fruit picking should account for more than 50-60% of the annual amount of fertilizer applied, and the specific amount of fertilizer should be combined with the age and potential of trees. It is suggested that winter fertilizer should be applied at the rate of 2-3 kg of organic fertilizer, 0. 1-0.2 kg of balanced compound fertilizer and 0.2 kg of calcium-magnesium-phosphate fertilizer per young tree. It is suggested that in the second year, young fruit trees should have 2-3kg of organic fertilizer per plant, 0.1-0.2kg of balanced compound fertilizer, 0.3kg of calcium magnesium phosphate fertilizer, 0.5g of microbial fertilizer/kloc-0, 5-8kg of organic fertilizer per adult fruit tree, 0.3-0.5kg of balanced compound fertilizer, 0.2-0.3kg of calcium magnesium phosphate fertilizer and 0.3kg of microbial fertilizer.

4. Fertilization should be suitable for citrus in winter.

Generally speaking, there are three main ways to apply fertilizer to citrus in winter: annular furrow fertilization, radial furrow fertilization and strip furrow fertilization: the first one is suitable for young fruit trees and weak trees, the third one is suitable for adult fruit trees and strong trees, and the second one is more suitable for spring and summer fertilization;

The ditching depth of citrus winter fertilizer is about 30 cm, and the best position for fertilization is the position under the vertical projection of the canopy at noon (that is, the canopy drip line). Fertilization position is too far away from the trunk, which is not conducive to the root system to absorb fertilizer, and fertilization position is too close to the trunk, which is easy to cause fertilizer burning.

Because the root system of weak fruit trees is underdeveloped, the best ditching position of fertilization ditch should be selected at the inner side of 1 under the crown projection, which can not only promote root absorption, but also shorten the old roots properly through fertilization, so as to promote roots and strengthen trees.

In addition, the use of winter fertilizer for citrus depends on the strength of the tree. It is suggested that the moderately strong trees should be ditched twice (such as furrow fertilization), and the weak trees should be ditched and fertilized around the fruit trees (such as ring furrow fertilization).

Third, do a good job in the management of deep ploughing and soil preparation in citrus orchards.

In the winter management of citrus, it is suggested that winter fertilizer should be applied in combination with fruit trees to dig deep into the soil of the whole garden. This has three main advantages:

First, it can break the soil hardening layer, improve the loose permeability of soil, and enhance the overall ability of orchard heat preservation, water conservation, fertilizer conservation and moisture conservation;

Second, it can promote the further activation and decomposition of deep soil, promote the transformation of soil nutrients and improve the soil fertility of orchard;

Third, it can destroy the overwintering place of germs and insect sources in the orchard and achieve the purpose of sterilization and pest control.

However, when digging into citrus orchards, we should pay attention to the following two points:

1. Deep ploughing in orchards is generally carried out after citrus fruits are picked and winter fertilizer is applied to fruit trees, and it is completed at the latest from ploughing time to February-March of the following year;

Second, it is best to master the turning depth at about 30 cm. The effect of turning the soil too shallow is not obvious, and turning the soil too deep is easy to cause freezing damage to citrus roots.

The main purpose and function of citrus fruit tree cultivation management is to improve the drought resistance, drought resistance and pest resistance of citrus fruit trees. In the operation time and method of cultivation, it is suggested that winter fertilizer should be applied in combination with citrus before winter, or from late autumn to the next year before fruit tree germination. When cultivating, the periphery of citrus trees should be covered with relatively fertile garden soil, and the cultivation thickness should be controlled at about 3-5 cm.

Fourth, do a good job in the winter pruning and shaping management of citrus.

Citrus pruning in winter is also one of the necessary and important measures for citrus winter management.

As for the pruning time, it is suggested that mature trees should be pruned about 2 weeks after fruit picking, because at this time, the focus of nutrient supply for trees has changed from supplying fruits to supplying leaves, and pruning is more conducive to the rapid recovery of tree vitality.

In the principle and method of pruning, it is suggested to follow the principle of "removing dense branches and keeping sparse, removing weak branches and keeping strong ones, leaving more strong branches and strong flowers, and less weak branches and weak flowers", focusing on pruning diseased branches, twigs, dead branches, horizontal branches, straight branches, drooping branches and dense branches, and combining with the management of old trees, scraping off diseased spots and whitewashing trees to make them clear from fruit trees and wither on the ground.

When trees are pruned, a large area of wounds should be smeared with liquid medicine after pruning to protect the wounds and promote healing.

When pruning young trees, attention should be paid to proper short-cut shaping treatment of branches, combined with late pruning and branch pulling for tree body shaping treatment;

When pruning trees in the fruiting period, attention should be paid to thinning out pests and diseases, weak branches, dead branches and cross branches in tree holes;

When pruning the fruiting trees in small years, we should pay attention to properly cutting off the fruiting mother branches and reducing the amount of flowers left to adjust the fruiting years.

When pruning weak fruit trees, we should pay attention to heavy pruning and regeneration, and cut off some weak main branches appropriately to enhance the overall tree potential and promote the rejuvenation of the tree potential;

When pruning the golden mean fruit trees, we should focus on retracting the secondary main branches that have moved out to prevent the fruiting branches and fruiting positions from moving out, and at the same time, we should pay attention to retracting or thinning the fruiting branches of the current year to promote the renewal and alternation of fruiting branches;

When pruning fruit trees at the initial fruit stage, attention should be paid to properly controlling the germination of winter shoots to promote flowering, so as to increase the fruit yield in the coming year.

Citrus whitening in winter can not only prevent diseases and insect pests, but also prevent low temperature freezing injury in winter. When painting fruit trees, the pests and diseases on the fruit trees should be cleaned up first, and then the trunk and side branches within 50 cm and 20 cm from the ground should be painted on sunny days. The height of whitewashing is suggested to be brushed below the fruit tree 1 side branch.

Fifth, do a good job in citrus water management in winter.

In winter water management of citrus orchards, generally, watering should be stopped immediately 20 days before citrus fruit trees are picked, so as to promote fruit coloring and sweetening, increase weight and yield, promote flower bud differentiation, and prevent fruit cracking, premature fruit drop or poor taste;

At the same time, during the period from the harvest of citrus fruit to the germination of fruit trees in the following year (especially in the late period of June 5438+February), water should be properly controlled in the orchard to promote the better differentiation of citrus flower buds.

However, from the fruit expansion stage to the coloring stage of citrus, if it encounters continuous rainy weather at this stage, it should be drained in time after the rain;

If the soil is excessively dry and the autumn leaves are slightly curled or withered from the swelling period to the noon of the coloring period of citrus fruit, it should be watered in time to prevent the citrus fruit from problems such as small fruit growth, poor discoloration, excessive acidity, insufficient sugar, fruit deformity, uneven fruit surface and poor flower bud differentiation due to lack of water, and at the same time enhance the cold and antifreeze ability of fruit trees in winter.

In addition, if there is cold air coming in the next few days, the fruit trees in the orchard should be watered in time for protection. It is recommended to irrigate the orchard for cold protection 2-3 days before cooling down.