(1) Safety of oranges The safety of oranges is relatively safe compared to other foods such as leaf vegetables in vegetables and berries such as strawberries in fruits and pears and apples. However, it cannot be said that citrus is a safe food. There are also many problems. Pesticide residues are mainly concentrated on the skin. Fresh oranges do not eat skin, while strawberries are whole foods. Apples and pears are also edible without peeling. Therefore, citrus is relatively safe from the perspective of fresh food. However, with the development of the processing industry, in addition to making juice or cans, it is also possible to extract essential oils, fruit acids, pigments, flavonoid glycosides, and dihydrochalcone sweeteners from processed skin dregs. High-value by-products and pomace feed, orange peel powder, orange peel jelly, dried marshmallows, etc.; therefore, pesticide residues on the skin can also exceed the standard. The current standards stipulate the pesticide residue limits in all or in the pulp. (2) The quality of oranges The quality of oranges is mainly due to pesticides and other residues. China's citrus is mainly used for domestic consumption, and is exported to Southeast Asia in small quantities. The main countermeasure after joining the WTO is to withstand the impact of foreign fruits. Therefore, it is necessary to improve the quality of oranges, occupy the vast domestic market, and allow the public to eat safe and high-quality food. fruit. The pollution-free food standards established in the year of 200l not only considered the safety and health issues of edible parts, but also considered the environmental quality issues of the entire production process. Therefore, these standards have established standards for the environmental conditions of production sites, including air quality, irrigation water quality, soil environmental quality, garden selection planning, the entire production process, and product quality inspection. These standards are advanced, scientific, and applicable. (3) Pollution-free citrus production The standard non-hazardous citrus production has two standards: they are product quality standards, production technical regulations and environmental conditions in production areas. The production technical regulations are the core and the aim is to control the quality and safety of citrus through the entire production process. If the majority of growers strictly follow the production technical regulations, they shall build the garden according to the standard, select suitable varieties and rootstocks, plant them in accordance with the standard, fertilize and apply water, prune and use plant growth regulators, and strictly follow the prevention and treatment methods prescribed in the standard to carry out pests and diseases. Comprehensive prevention and control, in particular, pesticides should be applied in accordance with the guidelines for the use of pesticides, and attention should also be paid to packaging, transportation, and storage after harvest to meet the criteria for pollution-free foods. Due to many links during and after harvest, this Ministry of Agriculture stipulated production technical specifications until harvesting. Only simple requirements for packaging, transport, and storage are included in the quality standards. Harvesting and post-harvest treatments are specified in separate standards. If the country strictly implements the pollution-free citrus quality standards, if it does not meet the standards, it will not be listed, and the general public will be able to enjoy safe and reliable citrus. (4) The environmental conditions for the production of pollution-free citrus are first discussed from the environmental conditions of citrus origin. Non-polluted citrus origin should be selected from agricultural areas that have good ecological conditions, are far away from pollution sources, and have sustainable production capacity. The production environment includes air quality, irrigation water quality and soil environmental quality. (1) Requirements for air quality Ambient air quality in nuisance-free orange producing areas should meet the following requirements: Limits of concentration of major pollutants in air quality: The average daily concentration of total suspended particulates in the pollutants is ≤ 0.30 mg/m3; Sulfur dioxide, daily average concentration ≤ 0.15 mg/m3, 1 hour average concentration ≤ 0.50 mg/m3; nitrogen dioxide, daily average concentration ≤ 0.12 mg/m3, 1 hour average concentration ≤ 0.24 mg/m3; fluoride (in F) The daily average concentration is ≤7 μg/m3, and the average concentration in one hour is ≤20 μg/m3. (Note: Pollutants all refer to the standard state.) (2) Quality standards of irrigation water The quality of irrigation water in non-polluted citrus origin should meet the following requirements. The concentration limits of various pollutants in irrigation water are: pH 5.5-8.5, total mercury ≤ 0.001 mg/L, total cadmium ≤ 0.005 mg/L, total arsenic ≤ 0.1 mg/L, total lead ≤ 0 mg/L , Chromium (hexavalent) ≤ 0.1 mg/l, Fluoride ≤ 3.0 mg/l, Cyanide ≤ 0.5 mg/l, Oils ≤ 10 mg/l, Chloride ≤ 250 mg/l. (3) Soil environmental quality requirements The environmental quality of soils from pollution-free citrus origin should meet the following requirements: The limits of the contents of various pollutants in soil (mg/kg) are as follows: Contaminants: Total cadmium pH value (5) Production technology The specific requirements are first of all climatic conditions. Citrus is a tropical subtropical fruit, requires a certain temperature, different varieties of the temperature requirements are different, the main indicator is the annual average temperature of 16-22 °C, the absolute minimum temperature ≥ -7 °C, January average temperature ≥ 4 °C, ≥ 10 °C accumulated temperature above 5000 °C. Followed by soil conditions. Generally, the soil has a good texture, loose and fertile, and the organic matter content is preferably above 1.5%. The soil layer is deep, and the live soil layer is preferably above 60 cm and the groundwater level is below 1 meter. There is also a slope of 25 or less. For hills and hills with a slope of 60-25, it is best to build horizontal terraces when building a garden. Specific requirements for citrus groves: During orchard planning, necessary roads, drainage and irrigation, water storage, auxiliary buildings and other facilities shall be constructed to create shelter forests. Shelter forests are particularly important in areas with typhoons. The tree species of the shelter forest should be adapted to the local environment, with rapid growth, erect and tall tree crowns, long life span, high economic value, and no symbiotic pests and diseases with citrus. If the typhoon is severe, multi-layer shelter forests will be planted to regulate the orchard temperature, increase the humidity, maintain water and soil, prevent wind damage, and reduce the wind speed. It will also reduce the damage caused by canker diseases and other citrus diseases. Because winds cause wounds, pathogens invade the wound. After the typhoon will rain, in the case of rain, ulcer disease (bacterial diseases) will spread. If there is a shelter forest, it will greatly reduce the damage. If the tree species of the shelter forest and citrus have no symbiotic pests and diseases, such shelter forests are also a barrier to citrus pests and diseases, and they can also play a protective role to reduce pests and diseases. At the same time, different varieties should also be selected based on the citrus ecoregion. (6) Selection of varieties Modern citrus seedlings generally use grafted seedlings, which consists of two parts: rootstock and scion. The intrinsic characteristics of varieties are generally represented by scion. According to the citrus eco-regionalization index, choose the most suitable area and suitable area. Excellent variety cultivation. Special attention should be paid to the selection of varieties with strong disease resistance and resistance. Ulcer wards are preferred to plant broad-leaved citrus. Ulcer disease is a bacterial quarantine disease that can spread with seeds, seedlings, scions, and fruits. Every year at least it takes more than 5-10 doses of pesticides, which increases production costs and increases pesticides in fruits. Residues. While the broad-leaved oranges are less susceptible to disease, it is best to plant broad-leaved oranges in the ulcer wards. Rootstock: Prior to the 1950s, citrus fruit trees were mainly proliferated. Since the 1960s, with the use of thin films on grafted seedlings and the introduction of fine rootstocks, grafting has spread throughout the country's citrus growing regions, changing the fruiting results of oranges for 8 years to 3 years, and citrus trees have turned into dwarfs. Due to climate, soil, pests, and other reasons, the selection of rootstocks is quite different. Must select good stocks suitable for the local climate, soil and pest resistance. China's rootstock varieties have been basically regionalized, and all citrus production areas have suitable rootstocks for production and development needs. Each kind of rootstock also has its compatible varieties, that is, the combination of anvil and panicles. Select and quote some resistant rootstocks. , Such as disease resistance, salt and alkali resistance, antifreeze and so on. Commonly used rootstocks are: wolfberry, orange, orange, taro orange, red orange, orange, sour and sour orange. Saline-alkali soil and calcareous purple soil should be selected from constitutive oranges and oranges, and the varieties (lines) that have been infected with split and leaf diseases cannot use alfalfa and alfalfa orange as rootstocks. Orchards are now being established, especially in high-standard orchards. We also recommend that non-environmental citrus production bases choose to plant virus-free seedlings if they have conditions when they build an orchard. The breeding method of virus-free seedlings is different from conventional seedlings. Its culture soil, breeding instruments and facilities are strictly disinfected before use. Irrigation water is up to standard. Rootstock seeds are also non-toxic, and the mother tree of scion must be identified or Registered virus-free or virus-free Tan strains. Strict protection during reproduction to prevent infection. The virus-free seedlings are free from any virus diseases. Therefore, after planting in the field, they grow rapidly, grow well, have strong resistance to diseases, and have less pests and diseases. (7) Seedling planting should first select seedling quality. If no virus-free seedlings are used, Grade A seedlings should be selected. The planting time is usually planted after the shoots mature from September to November or after the spring shoots from February to March. In the winter, there is a cold-damaged area suitable for planting in the spring, and the dry-hot valley area should be planted in the rainy season from May to June. Transplanting container seedlings or strips is not subject to seasonal restrictions. For flat slopes and slopes below 6 in gentle slopes, planting behavior is north-south and rectangular planting is recommended. In the mountainous and hilly areas with slopes of 6 to 25, the row direction of planting rows is the same as that of the terraced land, and it is recommended to use equal height planting. Planting density, based on the number of permanent plants planted per acre, generally 40-60 sweet oranges, spacing of 3 meters (4 to 5) meters, broadleaf citrus 60-70 strains, spacing of 3 meters 3.5 meters, pomelo 20 - 40 strains, spacing (4 to 5) meters (5 to 6) meters. Planting density should be based on variety, scion combination, environmental conditions and management level. Planting depth to the root neck exposed 5-10 cm above the ground is appropriate. The relationship between seedling planting and pollution-free production: Of course there are. Let us first talk about planting density. Planting too little and wasting land resources is not conducive to high yields. The planting is too dense, the thickness of the leaf curtain is thick, the humidity in the forest is large, and the light is poor. It is prone to diseases and pests that breed hi yin. At the same time, it is not conducive to uniform application of pesticides, and serious pests and diseases occur. Only to increase the frequency of application, increase environmental pollution and fruit pesticide residues. Besides planting depth. The planting is too shallow, it is easy to fall down, and it is uprooted when the wind is strong. Planted too deep, it is easy to induce foot rot. Therefore, it must be planted properly. After the seedlings are planted, soil fertilizer management must be strengthened. (8) Soil management The first step is to deepen the hole and ripen the soil. The second is intercropping or grass. Citrus Orchards are planted with grass or intercropped crops, and their types should not be associated with symbiotic pests and diseases on oranges. The reason is to avoid cross-infection. Grasses or inter-crops should be shallow roots and dwarfs, and legumes and grasses should be suitable. Mainly to increase the soil fertility, but also the host of natural enemies. The third is to cover and cultivate soil. In high temperature or dry season, the tree tray is covered with straw or the like. Soil is cultivated after cultivating loose soil in winter. Can be cultivated without pollution or detoxified pond mud, river sand, sandy soil or near fertile soil, thickness 8-10 cm. The fourth is cultivator. If cultivator is needed, it can be carried out in summer and autumn and after fruit picking, once or twice a year to keep the soil loose. The depth of the cultivator is 8-15 cm, the slope is deeper, and the flat surface is shallower. The rainy season should not be cultivated. Some pests that live in the ground for the winter can kill some by cultivating. Fertilization is an important part of orchard management. (9) Fertilizer management Fertilization, water management, and pollution-free production are quite relevant. The first is the principle of fertilization, which should fully meet the demand of citrus for various nutrient elements. Promote the application of organic fertilizers and reasonable application of inorganic fertilizers. Promote leaf nutrient diagnosis formula fertilization. Fertilizer types and quality: Farmyard manure includes compost, manure, manure, biogas, green manure, crop straw, mud and cake; commodity fertilizers include commodity organic fertilizer, humic acid fertilizer, organic compound fertilizer, inorganic (mineral) fertilizer , Organic-inorganic fertilizers, blended fertilizers and foliar fertilizers. The foliar fertilizer should be registered in the Ministry of Agriculture. The commodity fertilizer should be registered and certified by the relevant national authorities and the production license. The quality index should meet the relevant national standards. Human and animal urine, etc. must be fermented at a temperature higher than 50°C for more than 7 days. The municipal solid waste must be detoxified and its quality must meet the national technical standards before it can be used. The number of viable bacteria in microbial fertilizers must be in compliance with relevant regulations before application. In addition, it also prohibits the use of industrial waste containing harmful substances (such as toxic gases, pathogenic microorganisms, heavy metals, etc.), and restricts the use of fertilizers with higher chlorine content. Fertilization method: The first is soil fertilization. There is a ring groove application, a ditch and a soil release. The second is the foliar dressing, and the foliar dressing is stopped within 20 days before the fruit is harvested. Moisture management in fruit tree management is also an important part. Water management is also related to pollution-free production and has an important relationship. Water management includes irrigation and drainage. Irrigation requires no pollution and meets the quality standards of irrigation water in the environmental conditions of pollution-free citrus. In a rainy season or in an orchard when there is water accumulation, drain it in time. (10) Pruning, flower and fruit management Pruning is one of the important measures for citrus cultivation and management. Naturally grown citrus trees are often inconsistent with people's cultivation requirements. Therefore, they must be compensated according to people's wishes and in combination with the biological characteristics of citrus. From the perspective of pollution-free production, pruning, cutting pests and branches, reduce the source of diseases and insects; make the tree air and light, reduce the breeding grounds of pathogenic bacteria and hi insects, but also conducive to thorough spraying, which is the agricultural control of pests and diseases One of the measures. Oranges have a large amount of flowers, but the fruiting rate of sweet oranges is only about 1 to 5%. Wenzhou oranges and navel oranges are only 0.5 to 3%. Generally after two physiological fruiting falls, it is relatively stable. Therefore, in order to promote the relative balance between the vegetative growth of the tree and the flowering results, measures such as flower control, artificial fruit removal, and flower protection and fruit protection should be adopted. Close-planting gardens require early flowering and early fruiting, in order to increase the efficiency of the previous period, or the flowering of some varieties (such as pomelo), and the need to promote flower bud differentiation, therefore, the need to take measures to promote flowers. In recent years, as an important measure for pollution-free production, fruit bagging is recommended. The bagging period is from late June to mid-July (after the end of physiological fruit drop). Prior to bagging, the citrus grove should be sprayed 1-2 times in full according to the occurrence of local pests and diseases. Immediately after spraying, choose normal growing and robust fruits for bagging. Paper bags should be made of paper bags resistant to wind, rain, and air permeability. Single-layer bags are appropriate. After fruit bagging, the fruit surface can be bright and beautiful, and the coloring can be even, and the appearance quality and commodity rate of the fruit can be improved, the pesticide residue pollution, mechanical damage and pest damage can be reduced, and the proportion of sunburning fruit can be reduced. Pick the bag about 15 days before fruit harvest. (11) Use of Plant Growth Regulators Plant growth regulators are substances that have a stimulatory or inhibitory effect on the growth and development of plants. The application of plant growth regulators in the production of pollution-free citrus has the following provisions: The principle of its use is to allow limited use to improve tree growth, increase fruit yield, improve quality, and harmless to the environment and human health. Plant Growth Regulator. The types that can be used are: a. Cytokinin benzyl purines (BA) and kinetin are used only to promote germination and promote wound healing, prevent young fruit from falling off, and increase fruiting rate. B. Gibberellins: All gibberellin preparations. C. The use of ethylene and its release or inducer, ripening of the fruit can be thrown off ethylene or ethephon. D. Growth inhibitor use: paclobutrazol (PP333) and chlormequat (CCC) are available for production. The scope of application is limited to spraying on the foliage to prevent thick skin, control shoot growth and promote flower bud differentiation. The safety interval should be more than 30 days. (12) Integrated Pest Management This is the focus of pollution-free production. In general, the principle of prevention and control of citrus pests and diseases should implement the principle of plant protection based on prevention and comprehensive prevention and control. Based on agricultural and physical control, biological control is the core, and in accordance with the law of occurrence of diseases and insect pests and economic thresholds, scientific use of chemical control technologies is effective to control pests and diseases. The concept of integrated prevention and control: Integrated prevention and control is an integrated management of pests (IPM) proposed by the FAO at the 1967 Expert Meeting on Integrated Control of Pests. It is defined as comprehensive management of pests. The management system, which applies the appropriate techniques and methods as far as possible to keep the pest population below the level of economic hazards, in accordance with the environmental relationships associated with the pest population dynamics. At the national plant protection work conference convened in 1975, prevention was the mainstay, and comprehensive prevention and control was the policy for plant protection in China. In 1979, Mr. Ma Shijun, a veteran of plant protection industry, explained the contents of comprehensive governance. He said: Comprehensive management is based on the overall concept of biology and the environment, based on the guiding ideology of prevention, and it is safe, effective, and economical. Simplified principles, based on local conditions, rational use of agricultural, chemical, biological, physical methods, and other effective ecological methods, control pests to a level that does not endanger, in order to ensure the health of humans and animals. Increase the purpose of production. From the above discussion, we can see the three basic ideas contained in it, namely ecological viewpoint, economic viewpoint and environmental protection viewpoint. Pest and disease prevention and control should implement our policy of plant protection and focus on prevention. Therefore, for those dangerous pests and diseases that can be transmitted through human activities, quarantine measures must be taken. That is, quarantine pests and diseases are prohibited from being transferred from the affected area to the protected area, and the protected area may not transfer seedlings, scions, fruits, and seeds from the epidemic area, and are immediately destroyed upon discovery. In addition, according to Mr. Ma Shijun’s explanation, the methods used for comprehensive prevention and control are agricultural, chemical, biological, physical, and ecological methods. (13) Concrete measures for agricultural control Agricultural control mainly includes the following six measures. A. Planting shelter forest: The discussion above has been relatively clear and will not be discussed in detail. B. The selection of disease-resistant varieties and rootstocks has been described in detail above. C. Intercropping and grass cultivation in the garden: there are instructions in front. D. Implement agricultural measures such as turning soil, pruning, cleaning orchards, drainage, and controlling shoots to reduce the sources of pests and diseases. Turning the soil is discussed in the cultivating section, and the pruning is discussed before; clean orchards, such as the pruning of the branches and branches of the orchard or the dry branches, fallen leaves, and fruit drop, remove the orchard, and do a good job of orchard hygiene. The purpose is to reduce the source of pests and diseases, but also for the health of the fruit. In addition, the control tip is meaningful for some diseases and insect pests, such as some diseases and insects that cause damage to the shoots. These tips can be wiped off when the shoots are out of order, cut the food chain of the pests, reduce the source of diseases and insects, etc. Concentrate on medications when they are neat and tidy. Artificial methods can also be used, such as irrigation during drought, fertilization before irrigation, prompting neat shoots to be neat, and then concentrate on spraying. E. Strengthen the cultivation and management, improve the tree's ability to resist pests and diseases. That is to improve their immunity. The cultivation and management are done well, and the tree grows robustly. Even if there are pests and diseases, the performance is not serious. F. Improve the quality of fruit picking, reduce fruit wounds, and reduce the rate of fruit rot. Fruit rot is generally caused by disease. Invasion of pathogens is appropriate in the presence of wounds and environmental conditions. Therefore, try to avoid producing wounds when picking fruit.
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