(Lin Mouxin)

Citrus aurantium L. is also known as wolfberry orange, skin orange, fragrant orange and smelly orange. It is a small evergreen tree of the Rutaceae family. It is mainly produced in Jiangxi, Sichuan, and Hunan. Those produced in Sichuan are called Citrus aurantium Aurantii, those produced in Jiangxi are called Citrus aurantium Aurantii, and those produced in Hunan are called Citrus aurantium Aurantii. They are supplied to the whole country and exported. In addition, it is also produced in Hubei, Jiangsu, Zhejiang, Guangdong, Guizhou and other provinces. my country has been cultivating it as early as Xia Yu's time. The young fruits that fall off naturally and are used as medicine are called Citrus aurantium, and the nearly mature fruits are called Citrus aurantium. The peel contains volatile oil, nobiletin, citral, citronellol, p-hydroxyphen, hesperidin, neohesperidin, bitter orange acid, limonin, geranol, vitamins A, B, C, and P . The pulp contains organic acids such as citric acid. In recent years, the blood pressure-boosting components Sympathol and N-methyltyramine have been isolated from Citrus aurantium and Citrus aurantium husk. Pharmacological tests have shown that it has an obvious stimulating effect on the rabbit uterus in vitro and in vivo, can increase the contractility and tension of the uterus, can increase blood pressure, and can make gastrointestinal motility contractions neat and powerful. It tastes bitter, sour and slightly cold in nature. It has the functions of spreading qi, digesting food, and resolving phlegm. It is used for food accumulation, phlegm stagnation, chest and abdominal distension, gastroptosis, anal prolapse and uterine prolapse. Injections of Fructus Aurantii and Fructus Aurantii are used to increase blood pressure and fight shock.

In addition, there are Citrus aurantium L.var.amara Engl., C.wilsonii Tanaka. and Poncirus trifoliata (L. .) The fruits of Rafin.] are also used for medicinal purposes.

1. Morphological characteristics

The crown is umbrella-shaped or semicircular. The branches are triangular, smooth, and have long thorns. Single compound leaves, alternate; petioles have narrow or oblong-shaped wings; leaves are leathery, long-ovate or obovate, 3.5-10cm long, 1.5-5cm wide, entire or with inconspicuous wavy serrations, hairless on both sides. The lower mask has translucent oil spots. The flowers are solitary or clustered at the top of current branches or leaf axils, and are white; the calyx is cup-shaped and has 5 lobes; the citrus fruit is nearly spherical and slightly flat, orange or orange-red, with rough skin, sour juice and many seeds (Figure 15-47 ).

Figure 15-47 Morphological diagram of lime plant

1. Flower branch 2. Flower cut open, showing ovary ovule 3. Fruit 2. Biological characteristics

1. Root system

Strong regeneration ability. During the growth period, the growth and decline of growth often occur interactively with the above-ground parts. For 20-year-old solid trees, the diameter of the root system can reach 6-8.5m, and the root depth is 2.4-3m. But the main root system is mostly distributed in the soil layer of 25-90cm. Fibrous roots mostly grow in 8-30cm topsoil, growing fastest from late May to August.

2. Branch tips

The skin of the young branches is green, contains chlorophyll, and has stomata, which can carry out photosynthesis. Branch shoots can occur 3-4 times a year and can be divided into spring shoots, summer shoots, autumn shoots and winter shoots. Among them, spring, summer and autumn shoots occur most frequently. Regardless of spring, summer or autumn, the shoots can become fruit-bearing mother branches.

3. Leaves

As the number of leaves on the plant increases, the fruit harvest also increases proportionally. Leaf growth can occur throughout the year, but in a year, it occurs most in spring, followed by summer, again in autumn, and least in winter.

4. Flowers and fruits

The flowering period is from April to May, and the fruit ripening period is from November to December. The development of flowers and fruits is related to the number of flowers, pollination, weather and cultivation and management factors. Physiologically, the phenomenon of flower and fruit drop often occurs, and only a few can develop into fruits, and the phenomenon of fruiting every other year is also obvious.

(2) Requirements for environmental conditions

1. Light

Lime oranges are more tolerant of shade, but they are still better in the sun. According to experiments, the concentration of juice and leaf juice of fruits and leaves growing in the sun is greater than that of fruits and leaves growing in the shade. Especially during the flowering and young fruit growth periods, if there is insufficient sunlight, flowers and fruits will easily fall. But the light should not be too strong. Too strong sunlight will cause the decomposition of chlorophyll. Therefore, when the sunshine is too strong, the carbohydrate content of the fruits on the sunny side is lower than that of the fruits on the shady side. Moreover, the sunshine is too strong and the temperature is too high, which often causes sunburn.

2. Temperature

Likes a warm climate, and the annual average temperature is required to be above 15℃. The effective temperature for germination is above 10°C.

The suitable temperature for growth is 20-25℃, but the lowest temperature it can tolerate is about -9℃, and the maximum temperature it can tolerate, under conditions of sufficient moisture, will not drop leaves at around 40℃.

3. Moisture

It likes a humid environment and is suitable for growing in places with an annual precipitation of 1000-2000mm and a relatively even distribution of precipitation. Relative humidity is about 75%. If the humidity is too low, the fruit will be stunted, small in shape, thin in skin, not fresh in color, and the yield and quality will be poor. Excessive humidity, such as during the rainy season, causes poor root growth, yellow and weak leaves, and easy leaf fall due to heavy rainfall.

4. Soil

It has a wide range of adaptability to soil. Both red soil and yellow soil can be planted, but alluvial soil and gravel with deep soil layer, loose texture, good drainage and ventilation are preferred. Soil is the most ideal. Soil that is too heavy and poorly drained is not suitable for cultivation. It has a wide adaptability range to soil pH, ranging from pH 5.5 to 8.5, with pH 6.5 to 7.5 being the best. The choice of terrain is not strict, and it can be cultivated in mountains, hills, and plains. For mountain cultivation, sunny slopes are the best.

5. Fertilizer

Adequate fertilizer is required. Nitrogen has the greatest impact on vegetative growth and yield, and nitrogen, phosphorus, and potassium have the greatest impact on fruit quality. However, the lack of any other fertilizer elements will also cause special changes in its physiology, resulting in poor growth.

3. Cultivation techniques

(1) Site selection and preparation

The seedbed should be loam with convenient water source, deep soil layer, loose and fertile texture, and good drainage. Or sandy loam soil, preferably land that has not cultivated citrus seedlings. Before soil preparation, apply sufficient base fertilizer and plow 25-30cm deep. Before sowing, rake it flat to make a 1m wide border.

The planting site can be selected based on the seedbed. It is better to plow the wasteland one year before planting. You can also open holes with row spacing of 5-6m and plant-to-plant spacing of 4-5m before planting. The hole diameter is 50-70cm and the depth is about 50cm.

(2) Propagation methods

Seed propagation is the main method, but grafting can also be used.

1. Seed propagation

Winter sowing should be done after the seeds are collected that year, and spring sowing should be done in early or mid-March of the following year. Drill sowing is mostly used, with row spacing of 30cm and plant spacing of 3-6cm. After sowing, cover the seeds with fertilizer soil and then spread grass. Before emergence, the bed soil should be kept moist. After the seedlings break the ground, remove the covering in time. When the seedlings are 10-15cm tall, combine cultivating and removing pods, topdress human and animal manure and ammonium sulfate once, and topdress again in summer and autumn. To prevent frost in winter, a shed can be built to cover the seedlings. In the following spring, when the seedlings are about 1m tall, they can be transplanted with a row spacing of 30-50cm and a plant-to-plant spacing of 25-30cm.

2. Grafting propagation

There are many grafting methods. Here we mainly introduce two methods. The rootstock used for grafting is cultivated according to the seed propagation method. The two-year-old seedlings can be used as rootstock.

(1) T-shaped budding method

The most suitable time for budding is September to November. Before bud grafting, select a strong, high-yield, disease-free and insect-free mother tree, take the first annual branches, cut off the leaves, leave a little petioles, and use a bud grafting knife to cut off the buds and petioles from the branches to make the slices (bud grafts) appear as shields. Shape and slightly xylemous. Then, select the smooth side of the rootstock 6-8cm from the ground, use a bud grafting knife to make a "T" shaped incision, embed it and bind it after budding (Figure 15-48). After about half a month, gently touch the petiole on the bud. If it falls off at the first touch, the bud will turn new green, which proves that it has been grafted. For grafted buds, untie the bundles from February to March of the following year, and cut off the upper branches of the standing wood 0.5-1cm above the grafted buds to promote germination and growth of the grafted buds.

Figure 15-48 T-shaped bud grafting

1. Cut the buds 2. Cut the anvil 3. Inlay the buds 4. Bind

(2) Single bud Cutting method

The best time for cutting is from mid-March to mid-April. In early February, before the buds sprout, cut off the previous year's spring shoots or well-developed autumn shoots from the crown of the parent tree, cut off the leaves, tie every 50-100 branches into a small bundle, and bury them diagonally in a moist place. in fine sand to protect the viability of the scion. Open and inspect every 7-10 days before storing. Before cutting and grafting, first cut off the unfulfilled buds at the base of the scion, cut the surface at a 45° angle, turn it over and then cut off the cortex on the flat side of the scion with a slight xylem, cut the surface 1-2cm, and make an oblique cut above the bud, and then press Single bud cutting method is used to graft onto the rootstock and wrapped with plastic film tape (except for exposing the scion bud eyes, all grafting wounds are sealed) (Figure 15-49).

Figure 15-49 Single bud cutting

1. Cut the scion 2. Cut the anvil 3. Insert the scion 4. Bind

(3) Colonization< /p>

Mostly in late March. Before planting, add well-rotted compost or manure to the hole. For colonization methods, see Yuli.

(4) Field management

1. Cultivating and weeding

The principle is to eliminate weeds and prevent soil from compacting. Before summer, when there is a lot of rain, hoe sparingly and shallowly to prevent water accumulation in the garden and root rot. After summer, hoe diligently and deeply to conserve water and prevent drought. In winter, the temperature is low and there are few weeds. The weeds are only plowed and weeded once before applying winter fertilizer.

2. Fertilization

Fertilize fruit-bearing trees three times a year. There are three methods: ditch application, plate application and radial application. Dishes are the most common. The first application is in early March and is called spring fertilizer. The amount of fertilizer should be determined according to the vigor of the overwintering tree. If the tree is strong, apply less; if the tree is weak, apply more. The fertilizer is mainly retting human and animal manure, with dry cake and urea added as appropriate. This fertilizer can promote the growth of spring shoots and lay a good foundation for the current year's flowering and fruiting and the cultivation of the next year's fruiting mother branches. The second time is applied after fruit picking (from the end of July to the beginning of August) and is called tree-protecting fertilizer. Mainly use complete fertilizer, add urea as appropriate, and mix it with water. This fertilizer can promote tree vigor recovery and flower bud differentiation. The third application is in November and is called winter fertilizer. Its dosage accounts for about half of the total fertilizer amount throughout the year, mainly complete fertilizer, with optional addition of phosphate fertilizer, and attention should be paid to cultivating the soil and protecting the roots. This time fertilizer can continue to promote flower bud differentiation and tree vigor recovery, and enhance the tree's cold resistance. In addition, in recent years, according to the experience of chemical farmers, after the flowers fade, use 8-10 ppm2, 4-D, 0.5% urea, 1% superphosphate leachate, 3% plant ash leachate, trichlorfon 1000 times solution, dimethoate 1000 times. Six kinds of mixed liquids, including Douban liquid, can be sprayed on the leaves, which can not only prevent and control insect pests, but also reduce fruit drop.

3. Drainage and Irrigation

There is a lot of rain from April to June, and limes often suffer from root rot due to water accumulation, causing leaf and fruit fall. Pay attention to clear ditches and drainage. There is less rain from July to September, so water should be irrigated to resist drought to help restore tree vigor.

4. Land use

Peanuts, cotton, beans or vegetables can be interplanted in kindergartens. Intercrops should be kept at a certain distance from saplings to avoid competing for nutrients, water and sunlight from fruit trees and affecting the growth of saplings. In adult gardens, red flowers can be sown in early October and plowed into the soil as green manure in early April.

5. Pruning and pruning

It is an important measure to artificially control the growth and development of the tree, improve the lighting and ventilation conditions in the canopy, reduce damage from diseases and insect pests, and achieve high quality and high yield. The method of pruning should be based on the tree's strength and correctly adjust the relationship between the main branches and side branches, vegetative branches and fruiting branches.

(1) Shaping and pruning of saplings

Saplings are the period when the tree skeleton is forming. The quality of pruning affects the vigor of the lime tree, the phenomenon of large and small annual fruiting, and fruit abundance. The length of the period has a great impact. At present, natural semicircular or round head-shaped pruning methods are mostly used in production. That is, when the young tree trunk is about 1m high, select 4-5 branches that grow strong and evenly distributed on it and cultivate them as main branches. The distance between each branch is about 10cm. The top branch grows upward and is cultivated as the central leading trunk, and the other four branches grow upward. The branches stretch out in all directions, forming a strong tree skeleton. In spring, summer and autumn, wipe off the buds at inappropriate growth locations on the main trunk at any time, and pinch the elongated summer shoots to ensure even distribution of young branches, substantial growth, and balanced tree vigor. Within 2-3 years after planting, in order to facilitate the growth of vegetative bodies, all flower buds should be removed. In the next few years, the flower buds on the middle and upper branches of the crown can be appropriately thinned out to promote branch growth and rapidly expand the crown, but the lower and inner branches Can bear moderate amount of fruits.

When pruning young trees, it is necessary to combine light and heavy pruning, and lightness is better. Branches that hinder the growth of main branches and sub-main branches, as well as useless leggy branches, should be removed as soon as possible. Side branches that occur on the main branch and sub-main branches should be left as long as they do not intersect. However, the upright branches that occur on it must be removed as soon as possible. In addition, when pruning, it is necessary to thin out some branches that are too dense, and to appropriately shorten branches that have excessive growth potential, so that the main branches, sub-main branches and side branches maintain an obvious subordinate relationship.

(2) Pruning of adult trees

After limes bear fruit, the correlation between vegetative growth and reproductive growth becomes increasingly obvious as the age of the tree increases. Therefore, when pruning fruit-bearing trees, it is necessary not only to maintain strong tree vigor and cultivate excellent fruit-bearing mother branches, but also to regulate the relationship between growth and fruiting. It is usually pruned every other year, from February to March. The principle of pruning is to use sparse and dense leaves, and remove the weak and leave the strong. And according to the tree situation and shape, pay attention to cultivating preliminary branches.

Medicine farmers believe that the shape of a pruned tree is "like an umbrella when viewed from a distance, but sparsely scattered when viewed up close, with no large holes visible".

Based on the tree vigor of limes and the relationship between flowering, fruiting and yield, fruiting trees generally have the following three conditions, and their pruning is also different.

Pruning of large-year-old fruit-bearing trees: It is advisable to prune slightly, mainly thinning and pruning, supplemented by short cuts. Dense branches and clustered branches should be left strong and weak, thinned out, and pruned from the base. Most of the weak branches and bare branches can be cut off to reduce the number of flowers and avoid excessive consumption of tree nutrients. Strong branches with multiple rows of short cuts will encourage more shoots in the current year to become mother branches that bear fruit.

Pruning of young fruit-bearing trees: Mainly light pruning, try to retain strong branches to make them more fruitful. In addition to pruning dense branches, weak branches, shade branches, and leafless branches, more of the fruit-bearing mother branches should be retained.

Pruning of stable-yielding trees: It is required to be lighter than the big-year fruit-bearing trees and heavier than the small-year fruit-bearing trees. Use the pruning method that combines thinning and short cutting, and pay attention to cultivating strong branches as the fruiting mother of the next year. branches to lay a good foundation for high yields.

6. Cold protection

The roots and neck areas are susceptible to frost damage. Simple cold protection measures include: first, after applying winter fertilizer, apply turf, soil, and root mulch to each tree; second, combine antifreeze with insect control, and paint the trunks with whitening agent in winter.

(5) Pests and diseases and their control

1. Canker disease

[Xanthomonas citri (Hasse) Dowson]

Infects young leaves , young fruits and new shoots. In the early stage of the disease, yellow or dark green oil-stained lesions appear on the back of the leaves, and the leaves are slightly raised. The lesions are enlarged, almost round, yellowish brown, corky, slightly raised, relatively flat and smooth, and often have ring patterns. The protrusions on the back of the leaf are more obvious, the surface is rough, and the color is darker than the leaf surface. It will fall off and become perforated in the later stage. The lesions on branches and fruits are similar to those on leaves, but often without halos. After being damaged, leaf and fruit drop and abnormal growth often occur. In severe cases, branches dry up and die. High temperature and humidity are conducive to the occurrence of this disease, and the disease is most severe between 25-30°C. Prevention and control methods: Strict quarantine and select disease-free seedlings; cut off diseased branches and leaves in spring and burn them intensively; pay attention to the prevention and control of insect pests such as leafminers; spray 1:1:200 Bordeaux during spring shoots (or before flowering) and after flowers fade. Liquid, once every 7 days, spray 2-3 times continuously, then pull off the shoots, and spray the same pesticide for prevention and control; in order to avoid inducing rust tick damage, 10-15 days after spraying Bordeaux liquid from June to August, spray once US 0.3-0.5 degree lime sulfur mixture.

2. Soot disease

(Capnodium citri Berk, et Desm)

It damages leaves, branches and fruits. Dark brown mold spots appear in the early stages of the disease, and then expand to form a black mold layer, which affects photosynthesis. In severe cases, the plants will drop leaves and cause dead branches. Scale insects, whiteflies, and aphids can easily induce this disease. Prevention and control methods: Strengthen pest control; prune properly to allow ventilation and light transmission in the crown, strengthen field management, and pay attention to drainage during rainy seasons to make the tree grow vigorously and enhance disease resistance.

3. Star beetle

(Anoplophora chinensis Forster)

One generation per year, the larvae overwinter in the xylem holes of trees and pupate in April , emerge into adults from May to June, and adults still appear in July, laying eggs at the base of the trunk. The newly hatched larvae feed downwards in the bark, and then burrow into the xylem. Prevention and control methods: During the beetle spawning period from June to September, check frequently. Use a sharp knife to scrape off the eggs and newly hatched larvae on the trunk, and apply 5 times of 90% trichlorfon solution; use a cotton ball dipped in 5 times of 90% trichlorfon solution. Stuff the worm liquid into the wormhole, or use a syringe to inject the liquid into the wormhole, and then seal the hole with mud to poison the larvae, or kill the adults during the sultry noon and evening from May to August.

4. Phyllocnistis citrella Stainton

(Phyllocnistis citrella Stainton)

9 to 10 generations occur in a year, overwintering as pupae in the damaged leaf rolls, 5 It begins to damage spring leaves in September, and the damage is most severe from July to August, causing the leaves to curl and fall off. Seedlings and saplings are severely damaged, and large trees are slightly damaged. Control methods: Clean up fallen leaves in winter and spring and eliminate overwintering pupae; when the buds in summer and autumn do not exceed 5mm in length, spray 90% trichlorfon 500 times or 40% omethoate 1000 times once every 7 days, spray 2 times continuously Second-rate.

IV. Harvesting and processing

(1) Harvesting

Harvested from early July to late July. Too early, affecting yield. If it is too late, the fruit center will be enlarged and the quality will be poor.

The harvest period is closely related to the quality and dryness rate of limes (Table 15-39).

Table 15-39 Relationship between harvest period and lime quality and dry rate (weight: kg)

(2) Processing

1. Citrus aurantium Processing

Collect the young fruits that naturally fall off, cut the larger ones in half crosswise, keep the smaller ones intact, and dry them.

2. Processing of Citrus aurantium

After the fruit is cut in half, the fruit is dried in the sun with the skin facing upward to fix the skin color, and then turned over to the back and dried until it is 60-70% dry. , take it back and stack it, let it sweat, and then dry it in the sun. The ones with green-brown skin, thick flesh, hard texture and strong aroma are better.

5. Seed saving

Select individual plants that have entered the vigorous fruiting age, have high yields, high quality, and are free from diseases and insect pests. In the Jiangxi production area, 150-200 well-developed fruits are selected from each plant (the rest of the fruits are harvested for medicinal purposes). In November, when the fruits are fully mature, they are picked and placed indoors. After stacking for a period of time, the seeds are taken out and washed. After drying, mix in moist fine sand (1 part seeds, 3 parts fine sand) and hide it in a wooden box. Layer it and turn it regularly to prevent the seeds from mold and rot.