First, trim:
When cultivating Maogu Citrus in this province, we often don't pay attention to short cutting. Often, the top advantage of the apostles' long branches is too long, and the top advantage blooms and bears fruit after branching, which leads to the branches being too long and soft, and the branches are seriously bent after heading. In order to avoid heading, pruning of short branches should be strengthened in summer. Tree management of Maogu Citrus is mainly to maintain the tree shape and increase the crown by pruning, which can be divided into summer pruning and winter pruning. Summer pruning should be short and light, and the branches should be sparse. Adult trees grow moderately at full fruit stage, with less shoots in summer and autumn. However, if the plant grows vigorously and produces a large number of summer and autumn shoots, or even a large number of long branches, in addition to updating the mother branches, the long branches should be cut off to avoid causing a large number of fruit cracks.
. As for summer and autumn shoots, they should also be cut short to promote the formation of thin fruiting branches, and the redundant branches should also be cut off to avoid affecting the tree shape and fruit quality. However, after pruning a large number of summer and autumn shoots, we should also review and adjust the amount of fertilization and fruit thinning. Pruning in winter involves a large amount of pruning, but the pruning degree depends on the tree situation, and the pruning amount should not exceed 15%. In mid-February, prune dead branches, diseased branches, overlapping branches, thin branches, clustered branches or excessive fruiting mother branches. Pruning the big branches with strong tree potential should be carried out at the same time in winter, but pruning should be carried out year by year within 2 ~ 3 years to avoid excessive pruning at one time, affecting the crown distribution and causing a large number of redundant branches. When the tree vigor is weak, shortening pruning is used to reduce the crown and stimulate the germination of branches, so as to cultivate root groups and restore the tree vigor. Too many weak plants should be lightly cut, a large amount of high-carbon organic fertilizer should be applied to improve the soil, and a small amount of chemical fertilizer should be applied thinly to restore the tree vigor.
Second, thinning fruit.
Maogu Citrus is a very high-yielding variety. When these plants bear too much fruit in the new year, they should be thinned. For example, when the amount of fruit thinning is insufficient, when the fruit grows late, it often breaks too many branches. Moreover, too many plants bear too much load and consume too much nutrients in the tree, which makes the tree seriously deficient in nitrogen and potassium, but it causes a lot of fruit cracking and fruit dropping in the middle stage of the fruit, which leads to the yellowing of leaves in autumn and the weakening of the tree, which affects the fruit in the next year and even leads to the decline of the tree in serious cases. Therefore, fruit thinning should be done early. As for the amount of fruit thinning, it is appropriate to make the plant growth potential slightly greater than the fruit load. Even after fruit thinning, the plant can still produce a small amount of summer and autumn shoots as its balance point, which does not affect the tree potential, thus producing large and high-quality fruits and stabilizing the yield. In the new year, in addition to thinning fruit early, we should strengthen the management of fertilizer cultivation to prevent premature aging, especially in the application of nitrogen and potassium fertilizer, which is more than ordinary oranges and oranges. In order to avoid excessive flowering and fruiting, we should strengthen pruning in winter and cut off too long or too many fruiting mother branches to reduce excessive flowering and fruiting and reduce the workload of fruit thinning.
Third, fertilizer management.
Soil management:
Although the adaptability of Maogu citrus to soil is similar to that of ordinary citrus, in order to obtain excellent quality, special attention should be paid to the selection of soil. The ground and soil of the orchard should be well drained, that is, there should be no water accumulation after heavy rain, the thickness of the soil layer should be above 50 cm, and there should be no yak bottom (impermeable layer). The soil texture is better from loam to loam. The soil organic matter content is above 3%, the soil pH value is between 5.5 and 6.5, and the soil electrical conductivity (EC value) is below 2ms, so there is no salt damage. It is better to use hillside in leeward area, pay attention to drainage in flat land, and provide irrigation facilities to replenish water during soil drought. If the pH value of soil is lower than 5.5, it belongs to acidic soil. In acidic soil, plants often lack calcium or magnesium, which affects their quality. Alkaline materials such as limestone powder, oyster shell powder or shrimp shell powder can be used to improve the quality. However, dolomite powder (containing 10 ~ 16% magnesium oxide) should be used in magnesium-deficient orchards, and calcium and magnesium should be supplemented at the same time. Each plot is about 100 ~ 200 kg, and it must be mixed with organic fertilizer before it can be deeply applied to the soil layer.
Please refer to the recommended amount of citrus fertilization for the fertilization amount of Maogu Citrus. However, because Maogu Citrus is a very high product species, fertilization management should be strengthened to prevent premature plant decline, especially the amount of nitrogen and potassium fertilizer should be increased by about 20 ~ 50% compared with the recommended amount of general citrus fertilization.
(3) Fertilization period: during the fertilization period, base fertilizer (after harvest), summer fertilizer (June-August) and autumn fertilizer (9-65438+1October) are divided into 4-5 times; Topdressing is suitable in summer and autumn, and it is best to topdress after rain.
(5) Trace elements:
In addition to the above main elements, citrus may lack other elements, such as zinc, manganese, iron, boron, etc., which must be analyzed through soil and leaves. In case of deficiency, 40-80kg/ha of zinc sulfate (or 30-50kg/ha of zinc oxide), 200-400kg/ha of manganese sulfate and 50-60kg/ha of ferrous sulfate can be added to the soil at the same time. It can also be sprayed on leaves (young fruit to middle fruit) and diluted to a concentration of 0.25 ~ 0.5% with the above substances. When boron is deficient, 5 ~ 10 kg borax per hectare can be added to the base fertilizer, or water-soluble boron diluted to 400 ~ 500 times can be sprayed from young fruit to middle fruit, but it cannot be sprayed year after year to prevent poisoning.
(6) Fertilization method:
Generally, there are four application methods: furrow application, point application, ring application and spreading application. One of the first three kinds of base fertilizers can be used alternately, and usually spreading (surface application) is suitable for topdressing.
Trenching: Trenching between interlaces, with a width of about 30 ~ 40 cm and a depth of about 20 ~ 30 cm. The prepared organic fertilizer, soil improver and part of chemical fertilizer can be put into the ditch first, and then covered with soil.
Cave application: drill 5 ~ 8 holes around the crown with a drill, with a diameter of 15 ~ 20cm and a depth of about 40 ~ 50cm, and then apply all the adjusted base fertilizer and cover the soil.
Circumferential application: this method is suitable for young trees (1 ~ 3 years old). The ditch around the crown is about 20 ~ 30 cm wide and about 15 ~ 20 cm deep. Apply base fertilizer in the ditch and then cover it with soil.
Spreading: generally used for fertilization in summer and autumn (topdressing). Spread the prepared fertilizer evenly under the canopy, but when the soil is wet. If grass is cultivated, it can be cut and covered to improve fertilizer efficiency.
Fourth, prevent fruit from cracking.
The occurrence of citrus fruit cracking is generally due to the influence of cultivation, irrigation or season, which leads to irregular growth and unbalanced development of peel and pulp, leading to peel cracking and pulp. For example, when citrus plants are in long-term drought or lack of rain, the soil moisture is insufficient and the peel growth is suspended or delayed. However, when the pulp growth did not stop, when the soil got enough water, the plants absorbed a lot of water and nutrients for a period of time, and the pulp grew rapidly, while the peel grew slowly, which led to the difference between the peel and the pulp growth and led to the peel cracking. Usually, varieties with thin skin, such as Ponkan, Maogu Citrus, Navel Orange and some Valencia varieties, are more prone to fruit cracking. The fruit begins to crack at the top of the fruit, and sometimes cracks at the side of the fruit.
Maogu Citrus: Because of its thin skin, it is prone to fruit cracking, which occurs from the first fruit stage to the big fruit stage, and the fruit drop is serious, which often puzzles the cultivation and management of fruit farmers. Fruit cracks in different forms during the growth period. In the middle and small fruit period from August to September, the fruit often cracks vertically, that is, from the top of the fruit along the two sides of the fruit surface to the fruit stalk. On June 5438- 10, the fruit began to crack laterally, that is, from the side to the top and the stalk of the fruit. That is, if the rainy season stops for a period of time, such as 65438+ 10, it will occasionally rain, which will often cause a lot of fruit to fall horizontally and vertically. When the fruit dropping speed slows down, some fruit drops only appear near the fruit pedicle.
Measures to prevent fruit from cracking;
(1) Suitable for planting: planting in a cooler climate with an annual average temperature of about 20℃ can reduce the occurrence of fruit cracking.
(2) Strengthen the drainage of orchards: We should choose orchards with good drainage, set drainage ditches, and cultivate in high border. When it rains in rainy season, we can quickly discharge too much rain to prevent plants from absorbing too much water and reduce fruit cracking.
(3) Set irrigation facilities: during the fruit growing period, when the rain is insufficient and the soil is too dry, irrigation should be done moderately to keep the soil moderately moist, so as to prevent the soil from changing too much and reduce fruit cracking. Moreover, it is necessary to reduce irrigation water before the fruit ripens, which can not only increase the sugar content of the fruit, but also reduce the fruit cracking.
(4) Strengthen fertilization control: The fertilization method and period of Maogu Citrus is slightly different from that of ordinary citrus, that is, the total amount of phosphate fertilizer and organic fertilizer, about 30% of nitrogen and potassium fertilizer is used as ritual fertilizer after harvest, and about 70% of nitrogen and potassium fertilizer is applied three or four times from young fruit stage to middle fruit stage. If serious fruit drop has occurred in the young fruit period, it can be used immediately after heavy rain. In the middle stage of fruit from August to September, if fertilizer containing phosphate fertilizer is applied, it will increase the amount of fruit cracking and should be avoided.
(5) Strengthening pruning in summer: If a plant has a large number of branches in summer and autumn, the more branches, the greater the amount of fruit cracking. In addition to reviewing the amount of fertilizer application and reducing the amount of nitrogen fertilizer application, we should also cut off the tender branches to prevent the roots from absorbing too much water and causing a large number of fruit cracks due to vigorous plant growth.
Five, pest control:
After pruning plants in winter in mid-February, a winter prevention and treatment should be carried out. When the roots of plants are invaded by nematodes, the root tip grows stagnant and the roots rot, while the leaves above the ground are yellow, small and thin, or lack of trace elements. Especially during the low temperature and drought in winter, leaves are obviously yellowed and a large number of leaves fall early, plants bloom less and are easy to drop flowers and fruits, and fruits are of different sizes and poor quality. The density of root-knot nematodes should be checked immediately. The damaged plants should apply nematicides or chitin-containing additives in the ring ditch during the spring germination period, and then irrigate.
The flowering period of Maogu Citrus is in March, about 1 month. The harm of flower thrips is more serious than that of ordinary citrus, which affects the appearance of fruit. Spraying 1 ~ 2 times at flowering stage can be controlled, and the scar on the fruit epidermis can be reduced. After hanging fruit in early April, the control of scale insects, red spiders and rust ticks should be strengthened during the fruit growth period. Maogu Citrus is a hybrid of broad-peel citrus and sweet orange, so both citrus are susceptible to scab and canker, which should be prevented. Especially in orchards with high windward side, plant canker infection is serious in typhoon season, and prevention and control should be strengthened after typhoon. The control of Drosophila melanogaster should be strengthened from the big fruit stage to the mature stage. Please refer to the Handbook of Plant Protection published by the Agriculture and Forestry Department for pesticide control.
For reference.