The growth, development, flowering and fruiting of citrus fruit trees are closely related to environmental conditions such as temperature, sunshine, moisture (humidity), soil, wind, altitude, topography and slope direction, among which temperature is the most important factor. Even if the temperature difference is 0.5℃, sometimes there will be completely different results. The growth and development of citrus fruits need a temperature of 65438 02.5 ~ 37℃. The day and night temperatures of flower bud differentiation in autumn are about 20℃ and 65438 00℃, respectively, and the soil temperature of root growth is roughly the same as the ground temperature. If the temperature is too low, oranges will freeze. When the sweet orange is at -4℃ and the satsuma orange is at -5℃, the branches and leaves will be frozen. When the sweet orange is below -5℃ and the satsuma orange is below -6℃, the branches will be frostbitten. When the sweet orange is below -6.5℃, the satsuma mandarin will freeze to death.

Slightly resistant to shade, like warm and humid climate, not cold-resistant, freezing injury occurs when the temperature is lower than -8℃, and it is suitable for growing in deep and fertile neutral to slightly acidic sandy loam.

High temperature is also not conducive to the growth and development of citrus. When the air temperature and soil temperature are higher than 37℃, fruits and roots stop growing. Temperature also has obvious influence on fruit quality: in a certain temperature range, with the increase of temperature, the sugar content and soluble solids increase, the acid content decreases and the quality becomes better.

illuminate

Citrus is a tree species with strong shade tolerance, but good sunshine is needed for high quality and high yield. Generally, areas with annual sunshine hours 1200 ~ 2200 hours can grow normally. For example, compared with Chongqing citrus producing areas with less sunshine, South China with good sunshine and abundant calories has higher sugar content, lower acid content and higher sugar and acid content.

humidity

Generally, tropical and subtropical regions with annual rainfall of about 1000mm are suitable for citrus planting, but irrigation is often needed because of uneven distribution of annual rainfall. The suitable relative water content of soil is 60% ~ 80%, and irrigation is needed when it is lower than 60%. Too much rain will cause soil water accumulation or high groundwater level and poor drainage in citrus orchards, resulting in root death. Citrus fruit trees require that the air relative humidity should be around 75%.

land

Citrus can adapt to a wide range of soils. Purple soil, red and yellow soil, beaches and beaches can all grow at pH 4.5 ~ 8, and pH 5.5 ~ 6.5 is the most suitable. The growth of citrus roots needs high oxygen content, and the soil with loose texture, good structure, organic matter content of 2% ~ 3% and good drainage is the most suitable.

distribution range

Citrus in the world is mainly distributed in the area south of 35 north latitude, which is warm and humid, and the area with warmer water body can be pushed northward to 45 north latitude. Citrus is produced in 135 countries in the world, with an annual output of102822 million tons and an area of 1073 million mu, ranking first among the hundred fruits. Brazil ranks first with 24.2526 million tons, the United States ranks second with16.3352 million tons, and China ranks third with10 million tons.

Citrus in China is distributed between north latitude 16 ~ 37, with the highest elevation of 2,600 meters (Batang, Sichuan), starting from Sanya, Hainan Province in the south, reaching Shaanxi, Gansu and Henan in the north, Taiwan Province Province in the east and Yarlung Zangbo Grand Canyon in Tibet in the west. However, the economic planting areas of citrus in China are mainly concentrated between 20 ~ 33 north latitude and below 700 ~ 1000 meters above sea level. It is produced in the water system in the south of the southern slope of Qinling Mountain, the southern slope of Funiu Mountain and the southern Dabie Mountain, the southeast of Taiwan Province Province, the south of Hainan Island and the southwest of southeastern Tibet to low altitude areas. Cold-resistant site 9 ~ 1 1. There are 19 provinces (municipalities and autonomous regions) producing citrus in China, including Taiwan Province province. Among them, Taizhou, Fujian, Hunan, Sichuan, Guangxi, Hubei, Guangdong, Jiangxi, Chongqing, Taiwan Province and other provinces 10 are the main citrus producing provinces, followed by Shanghai, Guizhou, Yunnan, Jiangsu and other provinces (cities), and Shaanxi, Henan, Hainan, Anhui, Gansu and other provinces are also planted. Citrus is grown in 985 counties (cities, districts) in China.

cultivation techniques

The soil layer is required to be deep (60cm) and fertile; The slope of the orchard is less than 25 degrees. When planning a garden, there should be necessary roads, irrigation and drainage, water storage and ancillary building facilities. In terms of specific planning, we should concentrate on one place as much as possible and build gardens in places with good traffic and water conditions.

time

It is usually planted from February to March when spring buds sprout.

soil management

It is necessary to dig holes and solidify soil, prohibit planting tall plants such as corn and wheat in the garden, and do a good job in rational intercropping and intertillage weeding in the orchard.

Fertilizer and water management

(1) Fertilization principle: It is necessary to fully meet the demand of blood oranges for various nutrient elements, advocate more application of organic fertilizers, and rationally apply inorganic fertilizers and formula fertilizers. According to the results of leaf analysis, orchard soil analysis and blood orange phenology, fertilization is guided.

(2) Fertilization methods: mainly soil fertilization and foliar fertilization. The methods of annular furrow application, strip furrow application, hole application and soil surface fertilization were adopted.

(3) Fertilization of young trees: apply less fertilizer, mainly nitrogen fertilizer, with phosphorus and potassium fertilizer, and apply fertilizer 5-6 times in spring, summer and autumn when bamboo shoots emerge, (March, May, June, July, September, 65438+February, and apply 0.4 kg ammonium bicarbonate or 0.2 kg urea to each plant each time. 1-3 young trees should be applied with pure nitrogen 100-400g every year, and the ratio of nitrogen, phosphorus and potassium is1.0: (0.4-0.5):1.0. Adult trees should be fertilized four times, that is, germination accelerating fertilizer, fruit protection fertilizer, fruit strengthening fertilizer and fruit picking fertilizer. Generally, the amount of fertilizer applied is 2-3 kg of chemical fertilizer and one load of manure. Fruit-keeping fertilizer 1-2 kg phosphorus and potassium fertilizer+1 kg chemical fertilizer; Strong fruit fertilizer 1-2 kg chemical fertilizer+1-2 kg phosphorus and potassium fertilizer; The fruit picking fertilizer (base fertilizer) is mainly organic fertilizer, and each plant is applied with 50- 100 kg organic fertilizer+1-2 kg chemical fertilizer.

(4) Moisture: Irrigation when soil is dry, and drainage when water accumulates.

Plastic trimming

principle

Adjust measures to local conditions, prune trees, properly raise and lower them, and ventilate and transmit light to achieve three-dimensional effect.

Do plastic surgery

(naturally happy). The trunk is 20-40cm high, and the trunk branches (3-4 branches) are scattered on the trunk. The branching angle of the main branch is 30-50 degrees, and 2-3 auxiliary main branches are left on each main branch. Generally, after the third main branch is formed, the central trunk of this kind is cut off and twisted to one side to form a fruiting branch group.

decrease

(1) Young trees: mainly light pruning. After selecting the extension branches of the class center and the main branches and the extension branches of the auxiliary main branches, moderate or even severe pruning is carried out, and the growth balance among the main branches is adjusted according to the pruning degree and the direction of cutting buds. In addition to properly thinning the over-dense branches, the inner branches and weaker branches in the middle and lower part of the crown should generally be retained.

(2) Initial fruiting stage: continue to select short cutting to treat the trunk extension branches at all levels, erase the summer shoots, and promote the autumn shoots to be robust. In autumn, measures such as ring cutting, root cutting and water control are taken to promote the flowering of Wangshu.

(3) Full-fruiting period: the fruiting branches, falling branches and declining branches are retracted in time, and the light-blocking branches, dead branches and insect branches are cut off.

Eliminate pests and diseases

root rot

Timely drainage, improve the lighting and ventilation conditions in the park, and strengthen the prevention and control of trunk pests such as longicorn beetles; Selecting disease-resistant rootstocks such as Fructus Aurantii, Fructus Aurantii Orange and tangerine, and replacing infected plants with disease-resistant rootstocks.

mite

Before and after flowering (March-May) and autumn (9-165438+1October) are the key periods for controlling red spider: the population density reaches 1-2 heads/leaf before flowering, and it needs to be controlled after flowering and when it reaches 5-6 heads/leaf in autumn. The main periods of controlling rust lice are spring shoot sprouting, young fruit and fruit expansion: rust color appeared on the back of spring shoot leaves in that year; When the insect population density on leaves or fruits reaches 2-3 heads per leaf, control it immediately. Commonly used pesticides include hexythiazox, fenpropathrin, propargite, bromopropyl ester, chlorfenuron and so on. Pay attention to protect natural enemies, such as bearded mites, blunt mites, lacewings, etc.

balance

The key period of drug control: the first generation nymph stage of scale insects, the damage stage of a large number of terminal branches in the larval stage of scale insects (usually from early May to mid-June), and the peak period of scale insects. Commonly used drugs include buprofezin, methidathion, matrine+nicotine, levobuprofezin, oil emulsion and so on. Pay attention to improving the ventilation and light transmission conditions in the park; Protect and utilize natural enemies such as Japanese square beetles, red-lipped ladybugs, lacewings, golden aphids, Australian ladybugs and red ladybugs.

aphid

The killing rate of new shoots is 25%, and it should be sprayed immediately. Commonly used pesticides include chlordimeform, dimethoate and butachlor. Attention should be paid to the protection of ladybugs, Chrysopa grandis, aphid bees, etc. Cut off the overwintering eggs and reduce the pest base.