CN101745519A - Agricultural safety production operating method by utilizing low cadmium-accumulation Chinese cabbage - Google Patents

Abstract

The invention relates to a safe production technology of crops in cadmium-polluted soil environment, in particular to a method for safe production of Chinese cabbage variety Beijing Xin No. 3 with low accumulation of cadmium in cadmium-polluted soil. Plant Chinese cabbage with low accumulation of cadmium in cadmium-contaminated soil, use the aboveground part of Chinese cabbage with low accumulation of cadmium to repel and absorb the cadmium in the polluted soil, and the root to fix and absorb the cadmium in the soil, thereby preventing its upward transport to the aboveground part. The aboveground part is eaten or sold as a safe vegetable, and the root is given other proper treatment, so that the food safety of the vegetable can be guaranteed, and a large amount of cadmium in the soil can be fixed and adsorbed by using the non-edible part (root); by repeatedly planting this kind of vegetable crop, repeat the above The excessive cadmium in the polluted soil can be extracted continuously, and the cadmium content in the edible parts of Chinese cabbage also meets the standard of pollution-free and safe vegetables. The method has the advantages of low cost, no damage to the physical and chemical properties of the soil, no secondary pollution, and the advantages of simultaneous production and simultaneous treatment in the polluted soil.

Description

The method of implementing agricultural safety production by using Chinese cabbage with low cadmium accumulation

technical field

The present invention relates to the safe production technology of crops in cadmium polluted soil environment, specifically a method for safe production of cadmium-contaminated Chinese cabbage in cadmium-contaminated soil, which uses the rejection mechanism of low-accumulated heavy metal cadmium Chinese cabbage, in A safe production method can still be achieved in medium and low levels of cadmium-contaminated soil.

Background technique

In recent years, with the rapid development of my country's industrial and agricultural production, the pollution of cadmium (cadmium) in my country's soil environment has become increasingly serious. Numerous human activities, such as large-scale mining and smelting, electroplating, sewage irrigation and sludge application, and the use of cadmium-containing pesticides and fertilizers, have released a large amount of cadmium into the environment, causing extensive and serious soil cadmium pollution [Document 1: Zhou Qixing, Huang Guohong. Environmental biogeochemistry and global environmental change [M]. Beijing: Science Press, 2000.]. According to reports, the Dayu Mining Area in Jiangxi, the Zhangshi Irrigation Area in Shenyang City, and the Shachuan Irrigation Area in Shanghai are all typical areas polluted by heavy metal cadmium. More than 10% [Document 2: Xu Aichun, Chen Yitai. Research progress on regulation of cadmium-contaminated soil rhizosphere environment and phytoremediation. China Soil and Fertilizer, 2007, (2): 1-6.]. Excessive cadmium in polluted soil not only directly threatens the human living environment and food safety, but also can be enriched in the human body through direct contact or through the food chain, resulting in chronic poisoning, affecting the metabolism of calcium and phosphorus in the body, and causing damage to the kidneys, bones, and liver. Pathological changes can induce various diseases of bone, digestive system and urinary system, and can lead to malignant tumors. Therefore, the cadmium pollution in the soil environment needs to be remediated urgently.

At present, there are many technologies that can be used to remediate heavy metal pollution in soil. Traditional heavy metal contaminated soil treatment mainly uses physical or chemical methods such as soil solidification, vitrification, leaching, soil washing, guest soil method, and electrochemical method. These methods have the following disadvantages: (1) the cost is high, and one hectare of heavy metal-contaminated land is often as high as tens of millions of dollars, and it is difficult to use on a large scale; (2) the soil ecological environment is destroyed, resulting in loss of soil structure, soil biological activity and The degradation of soil fertility often requires secondary treatment; (3) secondary pollution, the process of using physical and chemical methods to remediate heavy metal-contaminated soil often causes re-pollution of the soil. Therefore, it is generally difficult to practically popularize and apply it in the remediation and treatment of large-scale and lightly polluted soil.

Compared with these traditional treatment technologies, phytoremediation technology, which emerged in the 1980s as an in-situ green restoration technology, has the advantages of low cost, no damage to the environment, no secondary pollution, and easy acceptance by people. , has gradually become a research and application hotspot in the field of environmental science [Document 3: Zhou Qixing, Song Yufang. Principles and methods of contaminated soil remediation [M] Beijing: Science Press, 2004.]. However, phytoremediation also has the following obvious shortcomings and deficiencies: (1) The biomass of hyperaccumulative plants is small and has obvious geographical distribution; (2) The remediation period is too long, usually hundreds of years; (3) The depth of phytoremediation of polluted soil Limited, can only remediate soil to the root depth of plants. Therefore, phytoremediation technology is greatly limited by these factors, and it is still difficult to promote it in my country (Document 4: Liu Weitao, Zhang Yinlong, Chen Zhemin, etc. Absorption and distribution of cadmium and zinc by green trees in mining areas[J]. Journal of Applied Ecology, 2008, 19(4)): 752～756.). In view of my country's actual national conditions, it is obviously unrealistic to stop farming in large areas of mildly polluted farmland for long-term phytoremediation or to use expensive engineering repairs.

Scientists have found that there are not only interspecific differences in the uptake and accumulation of cadmium by plants, but also significant intraspecific differences. Therefore, screening and cultivating crop varieties with low accumulation of soil cadmium and other harmful elements to ensure the safe production of agricultural products has become one of the most effective and reasonable ways at present. The research on the screening and breeding of crops with low accumulation of heavy metals has become a hotspot in the current domestic and foreign research. Numerous research results have shown that rice (Oryza sativa L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), corn (Zeamays L.) and peanut (Arachis hypogaea L.) and other crops such as peanut (Arachis hypogaea L.) have significant differences in the accumulation and distribution of heavy metals in different genotypes, and the corresponding genotypes with low accumulation of heavy metals were screened out (Reference 5: Arao T., Ishikawa S.Genotypic differences in cadmium concentration and distribution of soybeans and rice[J]. Japanese Agricultural Research Quarterly. 2006, 40, 21～30; Document 6: Zhang G.P., Fukami M., Sekimoto H.Genotypic differences in effects of cadmium on growth and nutrient at hepositions[ J]. Journal of Plant Nutrition, 2000, 23: 1337～1350; Literature 7: Chen F., Dong J., Wang F., et al. Identification of barley genotypes with low grainCd accumulation and its interaction with four microelements[J] ]. Chemosphere, 2007, 67, 2082～2088; Document 8: Florijn P.L., Van Beusichem M.L. Uptake and distribution of cadmium in maize inbred lines[J]. Plant and Soil, 1993, 150: 25-32; Document 9: McLaughlinM. J., Bell M.J., Wright G.C., et al. Uptake and partitioning of cadmium by cultivars ofpeanut (Arachis hypogaea L.) Plant and Soil, 2000, 222(1-2): 51～58.). However, there are still few studies on vegetable varieties with low accumulation of heavy metals, and Chinese cabbage varieties with low accumulation of cadmium have not been reported. Studies have shown that 70% of cadmium entering the human body comes from cadmium-contaminated vegetables (document 10: Ryan J.A., PahrenH.R., Lucas J.B. Controlling cadmium in the human chain: A review and rationale based on health effects[J].Environmental Research. 1982, 28: 251-302.). Therefore, screening and using Chinese cabbage with low accumulation of heavy metals for safe production in moderately and slightly cadmium-polluted soils has theoretical and practical significance, and has also attracted great attention from relevant departments.

Chinese cabbage (Brassica Pekinensis L.) belongs to the Brassica genus of the Brassica family. It is a typical low-temperature and long-sun biennial plant. It is a popular vegetable widely cultivated in Northeast China and even the whole country. According to statistics, Chinese cabbage is the vegetable crop with the largest planting area in my country, with an annual planting area of about 2.67 million hectares, accounting for 15% of the total planting area of vegetable crops in the country, and a total annual output of more than 100 million tons, accounting for 18.8% of the total national vegetable output (Document 12: Ministry of Agriculture. Vegetable planting area and output across the country in 2005 [J]. Chinese Vegetables, 2007, (1): 40-41.). Therefore, it is urgent and necessary to safely produce Chinese cabbage with low accumulation of cadmium in polluted soil.

Chinese cabbage is native to China and has a cultivation history of more than 1,500 years. The germplasm resources are extremely rich. Using the rejection mechanism of Chinese cabbage in the safe production and practice of cadmium-contaminated farmland soil has the following advantages: (1) Chinese cabbage has a long history of cultivation in China And the germplasm resources are abundant, which has laid a solid foundation for the screening work; (2) it can repair cadmium pollution while producing safely in cadmium-contaminated soil, so as to achieve the purpose of controlling while producing, killing two birds with one stone; (3) Chinese cabbage is delicious, Rich in nutrition, it has the reputation of "the king of all vegetables", and is deeply loved by the people; (4) Chinese medicine believes that Chinese cabbage is slightly cold and sweet, and has the functions of nourishing the stomach and promoting body fluid, eliminating annoyance and quenching thirst, diuresis and laxative, reducing phlegm and relieving cough, and clearing away heat. The effect of detoxification (5) Chinese cabbage is an important economic crop in China, which has been exported to Japan, South Korea, Southeast Asia, the European Union and North American countries, which has promoted China's economic development and export earnings; (5) Chinese people have long-term agricultural production, The rich experience in Chinese cabbage cultivation and management has been accumulated, so that the safe production of low-cadmium-accumulated Chinese cabbage in cadmium-contaminated soil has sufficient agricultural technical guarantee. Therefore, it is entirely feasible to screen out the Chinese cabbage varieties with low accumulation of cadmium from many Chinese cabbage varieties and use them in the safe production of polluted soil.

Contents of the invention

The object of the present invention is to provide a method for safe production of Chinese cabbage with low cadmium accumulation in cadmium-contaminated soil, and safe production of Chinese cabbage Beijing Xin No. 3 with low cadmium accumulation in cadmium-contaminated soil.

To achieve the above object, the technical solution of the present invention is:

The method of safe agricultural production using Chinese cabbage Beijing Xin No. 3 with low cadmium accumulation: plant Beijing Xin No. 3 Chinese cabbage with low accumulation of cadmium in cadmium-contaminated soil, and restore it while producing, so as to achieve the purpose of removing excess cadmium in the soil.

H＝15cm)，每盆最后定苗2株。投加镉的浓度(mg/kg)为0、1、2.5和5。定期浇水，使土壤含水量保持在田间持水量的40-90％。在镉污染土壤中种植该大白菜，该大白菜地上部排斥吸收污染土壤中镉，同时根部固定、吸附镉，从而阻止其向地上部转移；当大白菜生长60-85天成熟时，将大白菜地上部从污染土壤上收获，将根部移除后妥善处理，待下个生长期再种植第二茬，重复上述操作。所述的每次收割后的大白菜根进行专门集中处理，处理的方法包括焚烧、萃取回收铅或压缩后作无害化填埋。The Chinese cabbage planted in cadmium-contaminated soil is Beijing Xin No. 3, which is a vegetable crop with low accumulation of heavy metal cadmium. The planting of the Chinese cabbage in the cadmium-contaminated soil refers to directly sowing the Chinese cabbage seeds of the variety in the cadmium-contaminated soil, with 3-6 cabbage seeds per hole, the hole spacing is 10-60cm, and the ridge spacing is 10-60cm. The Chinese cabbage planted in cadmium-contaminated soil adopts outdoor pot cultivation and field field cultivation. Planting Chinese cabbage Beijing No. 3 in the pot experiment means directly sowing Beijing No. 3 seeds in plastic pots (

H=15cm), and finally set 2 seedlings in each pot. The concentration of cadmium (mg/kg) added is 0, 1, 2.5 and 5. Water regularly to keep the soil moisture at 40-90% of the field capacity. Plant the Chinese cabbage in the cadmium-contaminated soil, the aboveground part of the Chinese cabbage will repel and absorb the cadmium in the polluted soil, and at the same time, the roots will fix and absorb the cadmium, thereby preventing it from transferring to the aboveground part; The aboveground part of the cabbage is harvested from the contaminated soil, the roots are removed and treated properly, and the second crop is planted in the next growth period, and the above operation is repeated. The Chinese cabbage roots after each harvest are specially concentrated and processed, and the processing methods include incineration, extraction and recovery of lead, or harmless landfill after compression.

The Beijing New No. 3 Chinese cabbage seed is jointly developed and produced by the National Vegetable Engineering Technology Research Center and Beijing Jingyan Yinong Science and Technology Development Center.

In the present invention, Beijing Xin No. 3 Chinese cabbage is a Chinese cabbage variety with low accumulation of cadmium, and its plant genetic and chemical characteristics are as follows: the growth period is 60-85 days, the growth is vigorous, uniform, the outer leaves are dark green, and the leaves are wrinkled , the degree of expansion is small, the piles of the leaf balls are overlapped, the speed of growth is fast in the later stage, the balls are tight, and the net weight of a single plant is about 4 kg. Anti-viral disease, mold rot, downy mildew, good quality, resistant to storage and transportation, 7000-8000 kg of clean vegetables per mu.

According to the fertility status of cadmium-contaminated soil, nitrogen, phosphorus and potassium fertilizers to promote the growth of the Chinese cabbage were applied. The Chinese cabbage planted in the cadmium-contaminated soil adopts outdoor pot cultivation and field cultivation, waters regularly to keep the soil water content at 40-90% of the field water holding capacity, and pays attention to preventing cabbage caterpillars, aphids and ground maggots.

The Chinese cabbage Beijing Xin No. 3 used in the invention belongs to Brassicaceae Brassica plants, is a typical low-temperature long-sunshine biennial plant, and has high nutritional value and economic value. It can be directly sown in polluted soil, and can also be transplanted and grown rapidly. Compared with other crops, its cultivation management is simpler and easier to operate. It is a highly adaptable vegetable economic crop. Experiments have shown that Beijing Xin No. 3 is a Chinese cabbage variety with low accumulation of cadmium. It has strong tolerance to cadmium poisoning in the soil, and its aboveground cadmium content is lower than the national safety vegetable production standard.

The harvested Beijing Xin No. 3 can be used as a green vegetable for people to eat, and it can also be sold in the domestic market or exported abroad, thus reflecting its high edible value and economic value; in addition, the harvested cabbage root can be treated centrally, or Safe landfilling, or resource processing and recycling of cadmium, can avoid secondary pollution and produce certain economic benefits at the same time.

Advantage of the present invention and beneficial effect are as follows:

1. Compared with traditional contaminated soil treatment methods, the method of the present invention has the advantages of less investment, less workload, low technical requirements, high ecological safety, and no secondary pollution.

2. The present invention has good economic, environmental and ecological benefits. The method of the present invention is used as a safe production technology for polluted soil. The cadmium content in the aboveground part of the harvested Chinese cabbage is lower than the relevant national standard. Eating the cabbage will not cause harm to the human body, and higher economic benefits can be obtained by selling the cabbage; Chinese cabbage Beijing Xin No. 3 roots are treated intensively, which will not cause secondary pollution. At the same time, the fixed restoration process will not only not damage the soil ecological environment, but also help to improve soil degradation and productivity decline caused by heavy metal pollution, restore and improve its biodiversity.

Description of drawings

Figure 1 is the detection graph of shoot and root biomass of Beijing Xin No. 3 treated with different concentrations of cadmium.

Detailed ways

Example 1: Confirmation and simulation application of Chinese cabbage with low accumulation of cadmium under pot gradient

The potting experiment site is located in the Shenyang Ecological Station of the Chinese Academy of Sciences, which is located in the center of the Lower Liaohe Plain, about 35km away from Shenyang City, and belongs to the warm temperate semi-humid continental climate. There is no pollution source around the experimental site, which is an uncontaminated area of heavy metals. The potting test soil was collected from the surface soil (0-20cm) in the non-polluted area of the Shenyang Ecological Station of the Chinese Academy of Sciences. The soil type was meadow brown soil, and the heavy metal cadmium content in the soil was 0.17mg/kg.

H＝15cm)中，每盆装土2.5kg，平衡8-12周待用。将大白菜籽直接播种于盆内，每盆播种3-6粒，待发芽一周后间苗，根据白菜幼苗长势每盆留两株。每日根据盆中土壤水分状况，浇入适量自来水，使土壤含水量经常保持在田间持水量的40-90％左右。In this experiment, 4 treatments were set up, and each treatment was repeated 3 times. The cadmium concentrations (mg/kg) added were: 0 (control, no addition), 1, 2.5, and 5. The cadmium added in the experiment was analytically pure CdCl ₂ ·2.5H ₂ O, and a certain concentration of nitrogen, phosphorus, and potassium fertilizers were applied as the base fertilizer: 0.25g/kgN(CO(NH ₂ ) ₂ ), 0.065g/kgP and 0.124 g/kg K (K ₂ HPO ₄ ). After air-drying the test soil and passing through a 4mm sieve, mix cadmium and base fertilizer in solid form, mix well and put it into a plastic basin (

H=15cm), each pot is filled with 2.5kg of soil, and balanced for 8-12 weeks before use. Sow Chinese cabbage seeds directly in pots, sow 3-6 seeds in each pot, and thin out the seedlings after one week of germination, and leave two cabbage seedlings in each pot according to the growth of cabbage seedlings. According to the soil moisture status in the pot, pour an appropriate amount of tap water every day to keep the soil moisture content at about 40-90% of the field water holding capacity.

Plants were harvested after 60-85 days of plant growth. Divide the harvested sample into two parts, the root and the shoot, and rinse them with tap water to remove the soil and dirt adhering to the plant sample, then rinse with deionized water, drain the water, and kill at 105°C for 1 hour; Then dry at 65°C to constant weight, weigh the dry weight and pulverize for later use. Plant samples were digested by HNO ₃ -HClO ₄ method (the volume ratio of the two was 87:13), and the cadmium content was determined by atomic absorption spectrophotometer.

The experimental results are as follows:

Figure 1 shows the shoot and root biomass of Beijing Xin 3 under the above-mentioned different concentrations of Cd. Analysis of variance showed that, compared with the control (Cd 0), in the treatment of Cd concentration of 1, 2.5 and 5 mg/kg, the shoot and root biomass of Beijing Xin No. Tolerance, the treatment with Cd concentration less than 2.5mg/kg even has a certain promoting effect on its growth. However, when the concentration of Cd pollution was very high, that is, when the concentration of Cd was 5 mg/kg, the biomass of shoots and roots decreased slightly, but at a significant level (P>0.05), it also showed a large amount of Cd patience.

Referring to Table 1, it can be seen that with the increase of Cd concentration in the soil, the Cd concentration in the aboveground and roots of Beijing Xin 3 gradually increased, and its enrichment coefficient and transfer coefficient also tended to increase. However, in all Cd treatments, the aboveground Cd enrichment coefficient (ratio of aboveground and soil Cd content) and transfer coefficient (ratio of aboveground and root Cd content) of Beijing Xin No. 3 were always less than 1, that is, aboveground Cd The content is always lower than the Cd content in the soil and roots, which has the typical characteristics of Cd rejection plants. The average water content of the aboveground part of cabbage Beijing Xin No. 3 was measured in this experiment to be 90%. The maximum permissible content (MPC) of Cd in the safety and quality of agricultural products and pollution-free vegetables (GB18406.1-2001) is 0.05 mg/kg fresh weight (FW), and the cadmium content in the aboveground part of cabbage exceeds 0.50 mg/kg dry weight (DW). It is considered that Cd exceeds the standard. According to this standard, when the soil Cd concentration is less than 2.5mg/kg, the aboveground Cd content of Beijing Xin No. 3 is less than 0.50mg/kg, which meets the national pollution-free vegetable production requirements. When the soil Cd concentration was ≥2.5mg/kg, the aboveground Cd content of Beijing Xin 3 exceeded the national standard.

The above experimental results show that when the concentration of Cd in the soil is lower than 2.5mg/kg, the cadmium content in the aboveground part of Beijing Xin No. 3 is always lower than the national standard for the production of pollution-free vegetables, and the Cd content in the aboveground part is always lower than that in the roots. At the same time, it shows strong tolerance to Cd pollution, fully possesses the characteristics of low Cd enrichment plants, and is a low Cd enrichment plant. Moreover, the Cd content in the roots is greater than that in the soil, showing a strong absorption and fixation effect on Cd. Beijing Xin No. 3 has a strong tolerance to Cd, its shoots repel and absorb Cd, its roots fix and absorb Cd, and prevent its translocation in the shoots. These characteristics make it safe to produce in low-level Cd-polluted soils and gradually remove excess Cd made possible.

Table 1 The characteristics of low accumulation of Cd in Beijing Xin 3 under pot experiment conditions

Treatment concentration (mg/kg) Aerial parts (mg/kg) Root (mg/kg) Aerial enrichment factor transfer coefficient 0 0.08 0.38 0.21 1 0.22 1.96 0.22 0.11 2.5 0.90 4.25 0.36 0.23 5 3.15 8.62 0.63 0.37

Example 2: Field confirmation in Shenfu irrigation area and safe production of cadmium-contaminated soil

The experiment site is set in the experimental field of Shenfu Irrigation Area in Dongling District, Shenyang City, where the meteorological conditions are not much different from those of the Shenyang Ecological Station. The soil type is yellow brown soil, its physical and chemical properties are pH 8.5, organic matter 18.32mg/kg, total N 1.27mg/kg, total P 1.42mg/kg, available K 145.68mg/kg, total cadmium 1.25mg/kg. Sow Chinese cabbage seeds directly in the cadmium-contaminated soil, with 3-6 cabbage seeds per hole, the hole spacing is 10-60cm, and the ridge spacing is 10-60cm. According to the abundance and shortage of soil moisture, water from wells from time to time (Cd is not detected in the water), so that the soil moisture is often kept at about 40-90% of the field water holding capacity; Dosage of urea. Harvest Beijing Xin No. 3 after 60-85 days of growth, and the sample treatment is the same as in Example 1.

The experimental results are as follows:

Table 2 shows the low Cd accumulation characteristics and growth conditions of Beijing Xin 3 plots with different Cd concentrations. The aboveground content of Beijing Xin No. 3 is all lower than 0.50mg/kg, which meets the national standard for pollution-free and safe vegetables (GB18406.1-2001). As a low Cd accumulation Chinese cabbage, it can be popularized and planted in moderately and lightly polluted farmland soil without causing harm to human health. Converted according to the measured root average dry weight, under the pollution level of Cd 1.25mg/kg, the root dry matter yield of Beijing Xin 3 can reach 9.05kg/ha, and the cadmium taken away from the soil is 16.29mg/ha. The excessive Cd in the soil can be removed to some extent by the continuous production of Beijing Xin 3. It can be seen from this that it is realistic and feasible to use Beijing Xin No. 3 to repair soil cadmium pollution at the same time of safe production and soil cadmium pollution on mildly Cd (cadmium content of 0.5-2.5mg/kg) polluted soil.

Table 2 Low Cd accumulation characteristics and growth status of Beijing Xin 3 under field experiment conditions

Cabbage strain Containing Cd in the aerial part (mg/kg) Root contains Cd (mg/kg) Aerial enrichment factor Dry weight of aerial parts (g/plant) Root dry weight (g/plant) 1 0.23 1.88 0.18 58.72 11.76 2 0.27 1.69 0.22 66.96 12.43 3 0.34 2.23 0.27 57.13 15.29 4 0.35 2.12 0.27 63.22 14.36 5 0.26 1.65 0.20 68.33 11.23 6 0.22 1.99 0.18 65.24 16.45 7 0.33 2.08 0.27 57.15 17.04 8 0.35 1.78 0.27 65.82 10.88 9 0.41 2.13 0.29 61.29 13.41 10 0.39 2.45 0.28 66.15 18.44

The results of the examples show that the present invention utilizes low-accumulation Cd aboveground parts of Chinese cabbage to repel and absorb Cd in the enriched polluted soil, and the roots fix and absorb Cd in the soil, thereby preventing it from being transported upwards to the aboveground parts. When the Chinese cabbage grows to 60-85 Tianshi harvests Chinese cabbage as a whole, the aboveground part is eaten or sold as a safe vegetable, and the root part is given other proper treatment, so that the food safety of vegetables can be guaranteed, and a large amount of Cd in the soil can be fixed and absorbed by the non-edible part (root part); through repeated planting For this kind of vegetable crop, by repeating the above process, excess Cd in the polluted soil can be continuously extracted, and the Cd content in the edible parts of Chinese cabbage also meets the standard of pollution-free and safe vegetables. The method has the advantages of low cost, no damage to the physical and chemical properties of the soil, no secondary pollution, and the advantages of simultaneous production and simultaneous treatment in the polluted soil.

Claims (6)

1. A method for safe agricultural production of Beijing No. 3 Chinese cabbage with low accumulation of cadmium, characterized in that: planting No. 3 Chinese cabbage Beijing New with low accumulation of cadmium in cadmium-contaminated soil, repairing while producing, and realizing removal of the cadmium in the soil Purpose of excess cadmium. 2. according to claim 1, utilize the method for safe agricultural production of Beijing No. 3 Chinese cabbage with low accumulation of cadmium, characterized in that: the Chinese cabbage planted in the cadmium-contaminated soil is Beijing No. 3, and the Chinese cabbage is Vegetable crops with low accumulation of heavy metal cadmium. 3. according to claim 1, utilize the method for safe agricultural production of Beijing No. 3 Chinese cabbage with low accumulation of cadmium, characterized in that: said planting the Chinese cabbage in the cadmium-contaminated soil refers to the variety of Chinese cabbage seeds directly Hole sowing in cadmium-contaminated soil, 3-6 cabbage seeds per hole, hole spacing 10-60cm, ridge spacing 10-60cm. 4. according to the method for implementing safe production of agricultural products by using the Chinese cabbage Beijing Xin No. 3 with low accumulation of cadmium according to claim 1, it is characterized in that: the Chinese cabbage planted in cadmium-contaminated soil adopts outdoor pot cultivation and field field cultivation, Water regularly to keep the soil moisture at 40-90% of the field capacity. 5. The method for implementing safe production of agricultural products by utilizing Chinese cabbage with low cadmium accumulation Beijing No. 3 according to claim 1, characterized in that: the Chinese cabbage is planted in cadmium-contaminated soil, and the upper part of the Chinese cabbage repells and absorbs the polluted soil At the same time, the roots fix and absorb cadmium, thereby preventing its transfer to the above-ground parts; when the Chinese cabbage grows for 60-85 days and matures, the above-ground parts of the Chinese cabbage are harvested from the polluted soil, and the roots are removed and disposed of properly, until the next day. During the growth period, plant the second crop and repeat the above operation. 6. The method for safe production of Chinese cabbage Beijing No. 3 with low cadmium accumulation according to claim 1, characterized in that: the Chinese cabbage roots after each harvest are specially concentrated and processed, and the processing methods include burning, Extract and recover lead or compress it for harmless landfill.