A multiple cadmium-reducing and selenium-enriching stabilization material, its preparation method and application

Abstract

The present invention relates to the technical field of agricultural production, and specifically relates to a multi-functional cadmium-reducing and selenium-enriching stabilization material, its preparation method and application. The present invention uses milk vetch as an organic raw material, combines the selenium-enriching additive sodium selenite and cadmium stabilization materials such as potassium sulfide, diammonium hydrogen phosphate, and quicklime to prepare a multi-functional cadmium-reducing and selenium-enriching stabilization material. The present invention combines milk vetch with a variety of cadmium-reducing and selenium-enriching additives, which can not only ensure the nutrient components (N, P, K, S) required for crop growth, but also significantly improve the effect of cadmium reduction and selenium enrichment in crops, which is conducive to achieving the goal of cadmium reduction and selenium enrichment efficiently and quickly.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural production, and particularly relates to a multi-functional cadmium-reducing and selenium-enriching stabilization material, a preparation method thereof and an application thereof. Background Art

[0002] Selenium is an important trace element necessary for the growth and development of humans and animals, and has various physiological functions. Selenium can enhance the immune function of the body, eliminate free radicals in the body so that DNA in cells is protected, inhibit harmful substances from being converted into active compounds, delay and inhibit the process of cell malignancy, and thus has an anti-cancer effect. Existing research shows that more than 40 diseases in humans are closely related to selenium deficiency. Selenium deficiency can cause aging, cardiovascular diseases, Keshan disease, diabetes, osteoarthropathy, liver diseases and cancers, etc. It is reported that more than 40 countries and regions in the world are selenium-deficient.

[0003] Enshi in Hubei is a high-selenium area. Existing research shows that plants growing in high-selenium areas can not only enrich selenium in the environment, but also convert inorganic selenium into organic selenium through their own assimilation, forming selenium-supplement raw materials with high production utilization rate, no toxic side effects and scientific dosage control. Therefore, strengthening the research on the utilization of plant selenium resources in high-selenium areas and developing various types of selenium-rich products such as medicines, health products and foods with safe use and high bioavailability as raw materials is not only the need of the health cause, but also an effective way to promote local economic development. Therefore, the development of the selenium industry using plants, animals and microorganisms growing in selenium-rich areas has broad application prospects and practical significance. However, research shows that selenium and cadmium in the soil often coexist. Tang Shiqi et al. studied the selenium and cadmium contents of 3,950 surface soils and 362 crops in the Enshi area. The results showed that there was a high degree of consistency in the spatial distribution of selenium and cadmium in the surface soils of the Enshi area, and there was an obvious coexistence relationship between selenium and cadmium in the soil. Another study showed that the selenium and cadmium contents in crop grains were significantly positively correlated with the selenium and cadmium contents in the soil, that is, the higher the selenium and cadmium contents in the soil, the higher the selenium and cadmium contents in crop grains. Therefore, in most selenium-rich plants growing in selenium-rich soil, the cadmium content also significantly exceeds the standard, which seriously affects the quality and value of selenium-rich products and also poses a threat to food safety. Therefore, reducing the cadmium content in selenium-rich plants is not only the need to improve the quality and value of selenium-rich products, but also the need to ensure the safety of selenium-rich foods. At present, the serious excess of cadmium content in selenium-rich plants has become a key problem that must be solved in the development of the selenium industry and is also a technical bottleneck in the development of the selenium industry in the Enshi area.

[0004] Research shows that the cadmium content in crops is not only related to the total amount of cadmium in the soil, but also to the bioavailability of cadmium in the soil. The lower the bioavailability of cadmium, the less cadmium is absorbed by crops. Therefore, when the total amount of cadmium in the soil is certain, reducing the bioavailability of cadmium is an effective way to reduce the cadmium content in crops. Research shows that the main factors affecting the bioavailability of cadmium in the soil include the total cadmium content in the soil, soil pH, soil adsorption of cadmium, soil redox potential, soil organic matter and phosphorus content, etc. At present, a large number of scientific researchers have conducted extensive research on the mechanism of these factors affecting the bioavailability of cadmium in the soil and the cadmium reduction effect of crops, and have achieved some results. However, the methods reported so far all reduce the bioavailability of cadmium in the soil by changing a single factor (single cadmium reduction measure), thereby reducing the absorption of cadmium by crops, and the cadmium reduction effect is poor. In addition, the occurrence form of cadmium in the soil changes with the change of the soil environment. The single cadmium reduction measure is greatly affected by the change of the soil environment, and the cadmium reduction effect varies greatly in different soil environments, and it is greatly limited in practical applications. Summary of the Invention

[0005] In order to reduce the absorption of cadmium in the soil by plants while increasing the absorption of selenium by plants, the present invention uses milk vetch as an organic raw material, and at the same time considers the dosages of elements such as nitrogen (N), phosphorus (P), potassium (K), sulfur (S), selenium, etc. required for crop growth, and adds cadmium stabilization materials (which can react with cadmium in the soil and convert cadmium into substances that cannot be absorbed by plants, such as potassium sulfide, diammonium hydrogen phosphate, lime, etc.) and selenium-rich additives (such as selenite) to prepare a multi-cadmium-reducing and selenium-rich stabilization material, and uses dryland and paddy field crops to respectively screen out cadmium-reducing and selenium-rich stabilization materials with better effects on dryland and paddy field crops.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A multi-cadmium-reducing and selenium-rich stabilization material, comprising the following components: milk vetch, selenium-rich additive, cadmium-reducing additive; wherein, the selenium-rich additive is selected from one or more of sodium selenite, potassium selenite, ammonium selenite, and the cadmium-reducing additive is one or more of sulfides, acid phosphates, and quicklime.

[0008] Preferably, the sulfide is selected from one or more of sodium sulfide, potassium sulfide, ammonium sulfide; the acid phosphate is selected from one or more of diammonium hydrogen phosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, diammonium dihydrogen phosphate, disodium dihydrogen phosphate, dipotassium dihydrogen phosphate.

[0009] More preferably, the multi-cadmium-reducing and selenium-rich stabilization material comprises the following components: milk vetch, sodium selenite, diammonium hydrogen phosphate, and quicklime.

[0010] More preferably, the multi-cadmium-reducing and selenium-enriching stabilizing material comprises the following components: milk vetch, sodium selenite, potassium sulfide, diammonium hydrogen phosphate, and quicklime.

[0011] Preferably, the mass percentage of sodium selenite is 0.5%, the mass percentage of potassium sulfide is 8%, the mass percentage of diammonium hydrogen phosphate is 40%, and the mass percentage of quicklime is 11.5%.

[0012] The present invention also provides a preparation method of the above multi-cadmium-reducing and selenium-enriching stabilizing material, comprising the following steps:

[0013] (1) Harvest the above-ground part of milk vetch, dry it in the sun and then crush it.

[0014] (2) Weigh the milk vetch, selenium-enriching additive, and cadmium-reducing additive obtained in step (1) according to the formula, and mix them evenly.

[0015] The present invention also provides the use of the above multi-cadmium-reducing and selenium-enriching stabilizing material in crop planting, preferably in the planting of rice, pakchoi, and / or Chinese flowering cabbage. The use is to apply the multi-cadmium-reducing and selenium-enriching stabilizing material as a base fertilizer into the soil once before crop planting and mix it evenly, wherein the application amount of the multi-cadmium-reducing and selenium-enriching stabilizing material per mu of land is 100 kg.

[0016] The selenium content in crops is determined by various factors such as the total selenium content in the soil, the pH of the soil, and the growth environment. The higher the total amount and bioavailability of selenium in the soil for growing crops, the more selenium the crops will absorb. The main forms of selenium in the soil are mainly organic selenium and inorganic selenium. During the process of growing crops, the selenium absorbed by the crops is only a part of the selenium in the soil. The main forms of selenium in the soil are related to factors such as the total selenium content in the soil, organic matter, redox conditions, and soil texture. Therefore, increasing the bioavailability of selenium in the soil is an effective way to increase the selenium content in crops. The organic compounds in the soil can undergo a coordination reaction with heavy metal ions in the soil, fixing the heavy metal ions in the soil and preventing them from being absorbed by the crops. Therefore, increasing the content of organic matter in the soil can reduce the absorption of heavy metal ions by plants. In addition, in an acidic environment, selenium in the soil mainly exists in the form of selenite, which is easy to form oxides and hydrates insoluble in water with iron, etc. Therefore, an alkaline environment is beneficial to the absorption of selenium by crops. The absorption of selenium by crops is also related to the viscosity of the soil. The greater the soil viscosity, the less conducive it is for crops to absorb selenium. Therefore, reducing soil viscosity is also one of the effective ways to increase the absorption of selenium by crops.

[0017] The present invention uses milk vetch as an organic raw material, combines K2S, (NH4)2HPO4, CaO, and selenite, etc. to prepare a multi-cadmium-reducing and selenium-enriching stabilizing material and apply it into the soil. In addition to the cadmium-reducing stabilizing material itself being able to significantly increase the pH of the soil environment, the Ca in it2+ , K + and others can also undergo displacement reactions with Al 3+ , H + in the soil environment to produce precipitates, making the soil environment alkaline, thus facilitating the absorption of selenium by crops. Organic selenium in the soil is the main source of available selenium in the soil. It forms organic-mineral complexes through complexation with humus or organic matter in the soil. After applying milk vetch as green manure, the content of soil organic matter can be increased. The increase in organic matter content can promote mineralization, convert selenium in the soil into a form that is easily absorbed by crops, improve the availability of selenium, and thus increase the absorption of selenium by crops.

[0018] The cadmium content in crops is determined by factors such as the total cadmium content in the soil, soil organic matter content, soil pH, and growth environment. When the cadmium content in the soil is constant, the lower the biological availability of cadmium in the soil, the less cadmium is absorbed by crops. Therefore, reducing the biological availability of cadmium in the soil is an effective way to control the cadmium content in crops. When milk vetch decomposes, it can increase the content of soil organic matter and reduce the biological availability of exogenous cadmium in the soil. In addition, the decomposition of milk vetch increases the soil pH value, promoting the combination of ion-exchangeable cadmium with OH - to form insoluble substances Cd(OH)2 and CdCO3, which are then fixed in the soil. Cadmium in the soil can also undergo physical or chemical interactions with the organic matter obtained from the decomposition of milk vetch and be adsorbed into the soil, thereby reducing the absorption of cadmium by crops. Inorganic alkaline materials such as K2S, (NH4)2HPO4, and CaO can not only significantly increase the pH of the soil environment by themselves, but also Ca 2+ , K + and others can undergo displacement reactions with Al 3+ , H + in the soil environment to produce precipitates, making the soil environment alkaline and further promoting the fixation of cadmium in the soil.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention combines milk vetch and a variety of cadmium-reducing and selenium-enriching additives to develop a stabilizing material with multiple cadmium-reducing and selenium-enriching effects. It can not only ensure the nutrient components (N, P, K, S) required for crop growth, but also significantly improve the cadmium-reducing and selenium-enriching effects of crops, which is conducive to efficiently and rapidly achieving the goal of cadmium reduction and selenium enrichment. In addition, the multiple cadmium-reducing and selenium-enriching stabilizing material of the present invention has obvious yield-increasing effects on both paddy field crops and dryland crops. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a bar chart showing the selenium and cadmium contents in brown rice under different treatment methods in Example 2;

[0022] Figure 2It is the distribution coefficient diagram of selenium in various parts of rice under different treatment methods in Example 2;

[0023] Figure 3 It is the distribution coefficient diagram of cadmium in various parts of rice under different treatment methods in Example 2;

[0024] Figure 4 It is the bar chart of the contents of selenium and cadmium in pakchoi under different treatment methods in Example 3;

[0025] Figure 5 It is the bar chart of the contents of selenium and cadmium in Chinese flowering cabbage under different treatment methods in Example 3. Detailed implementation manners

[0026] To make the objectives and technical solutions of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments and the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] The test site of the present invention is located in the Experimental Engineering Center of Hubei Minzu University. This area belongs to the subtropical monsoon and monsoon humid climate, with an altitude of 432 m and an average annual temperature of 14 - 22 °C.

[0028] The rice seedlings (En 6 You 1038) used in the following examples were provided by the Agricultural Academy of Sciences of Enshi Tujia and Miao Autonomous Prefecture. The pakchoi seeds were purchased from HeShuo Technology Co., Ltd. (China, Cangzhou, Cream Pakchoi), and the Chinese flowering cabbage seeds were purchased from HeShuo Technology Co., Ltd. (China, Shanghai, Chinese Flowering Cabbage).

[0029] The milk vetch seeds (Leping milk vetch) were purchased from Jiangxi Milk Vetch Seed Co., Ltd. (China), diammonium hydrogen phosphate (analytical pure) was purchased from Tianjin Zhiyuan Chemical Reagent Co., Ltd. (China), potassium sulfide (analytical pure) was purchased from Xiya Chemical Technology Co., Ltd. (China), sodium selenite (analytical pure) was purchased from Hunan Fengrun Biotechnology Co., Ltd. (China). The lime mentioned below all refers to quicklime and was purchased from the local market in Enshi City.

[0030] The soil used in the following examples is yellow brown soil, which was taken from Mufu Village, Mufu Sub-office, Enshi City, Hubei Province. After removing stones and plant rhizomes from the collected soil samples, they were air-dried, ground fine, sieved, and stored for later use. The basic physical and chemical properties, selenium and cadmium contents of the collected soil are shown in Table 1.

[0031] Table 1: Basic physical and chemical properties, selenium and cadmium contents of the test soil

[0032]

[0033] Example 1: Preparation of Multi-Cadmium-Decreasing and Selenium-Enriching Stabilization Materials

[0034] The milk vetch seeds were sown in October of the previous year and grew under natural conditions. In April of the following year, the above-ground parts of the milk vetch (including stems, leaves and flowers) were harvested before the full-bloom stage, dried and then crushed. Then, different proportions of various cadmium-decreasing substances (potassium sulfide, diammonium hydrogen phosphate, lime) and selenium-enriching additives (sodium selenite) were added to the milk vetch to prepare different multi-cadmium-decreasing and selenium-enriching stabilization materials, and their components and proportions are shown in Table 2.

[0035] Table 2: Components and Proportions of Multi-Cadmium-Decreasing and Selenium-Enriching Stabilization Materials

[0036]

[0037] Example 2: Effects of Multi-Cadmium-Decreasing and Selenium-Enriching Stabilization Materials on the Uptake of Selenium and Cadmium by Paddy Field Crops and Their Agronomic Traits

[0038] 1. Experimental Method

[0039] Paddy field crops were cultivated in pots, and the experiment was carried out in the Experimental Engineering Center of Hubei Minzu University, simulating field cultivation in an open-air manner. Rice was selected as the paddy field crop for the experiment to screen different multi-cadmium-decreasing stabilization materials. All the above-mentioned topsoil (collection depth 0 - 20 cm) was used in all the experiments. The plastic pots used had a diameter of 43 cm and a height of 25 cm, and 10 kg of soil was used in each pot. Eight treatment methods were set up, corresponding to the 7 multi-cadmium-decreasing and selenium-enriching stabilization materials in Example 1 (treatment methods 1 - 7) and 1 blank (CK) control (treatment method 8), and 3 replicates were set for each treatment. In all the experiments, the multi-cadmium-decreasing and selenium-enriching stabilization materials were applied as base fertilizers into the soil at one time and mixed evenly, with 5.8 g applied to each pot. For the blank control experiment, the multi-cadmium-decreasing and selenium-enriching stabilization materials were replaced with the corresponding amounts of nitrogen, phosphorus and potassium fertilizers according to the corresponding treatment. Flood irrigation was carried out 1 - 2 days before transplanting rice seedlings in the paddy field. According to the cultivation and management methods of rice, the water layer was maintained at 1 - 3.5 cm in the early tillering stage, at 7 - 13 cm in the jointing and booting stage, and at 5 cm after the flowering stage of rice when the water demand of rice decreased, and water was cut off 10 days before harvest. Attention should be paid to the prevention and control of pests and diseases during the planting process. After harvest, taking the selenium and cadmium contents in rice as indicators, the effects of different multi-cadmium-decreasing and selenium-enriching stabilization materials on reducing cadmium and enriching selenium in paddy field crops were compared, and the multi-cadmium-decreasing and selenium-enriching stabilization material with the best effect on reducing cadmium and enriching selenium in paddy field crops was screened out.

[0040] The rice was harvested 140 days after transplanting when the grains were mature. Then, the rice was separated into roots, stems, leaves, and grains, and washed thoroughly with tap water and deionized water in sequence. The roots, stems, and leaves were blanched at 105 °C for 30 min, dried to a constant weight at 70 °C, pulverized, and sieved (100 mesh) for later use. The grains were sun-dried, dehulled to obtain brown rice, and then pulverized and sieved (100 mesh) for later use.

[0041] The soil pH was determined by the potentiometric method (water extraction); soil organic matter was determined by the external heating method with potassium dichromate-sulfuric acid; total soil nitrogen was determined by the semi-micro Kjeldahl method; soil available nitrogen was determined by the alkaline hydrolysis diffusion method; total phosphorus was determined by the sodium hydroxide melting-molybdenum antimony anti-colorimetric method; available phosphorus was determined by the sodium bicarbonate solution extraction-molybdenum antimony anti-colorimetric method; total potassium was determined by the sodium hydroxide melting method; available potassium was determined by the 1 mol / L neutral ammonium acetate solution extraction of soil available potassium-flame photometry method; the cadmium and selenium contents of the soil and samples were determined by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion.

[0042] The absorption and accumulation of selenium or cadmium in different parts of the crop, the ability of the crop to transport selenium or cadmium, and the distribution of selenium and cadmium in different parts of the rice were represented by the enrichment coefficient, transport coefficient, and distribution coefficient, respectively. The calculation formulas for the enrichment coefficient, transport coefficient, and distribution coefficient are as follows.

[0043] Enrichment coefficient (BCF) = content of Cd (Se) in roots, stems, leaves or grains of plants (mg·kg -1 ) / total content of Cd (Se) in soil (mg·kg -1 );

[0044] Transport coefficient (TF) = content of Cd (Se) in organ A of plants (mg·kg -1 ) / content of Cd (Se) in organ B of plants (mg·kg -1 );

[0045] Distribution coefficient = content of Cd (Se) in roots, stems, leaves or grains of plants (mg·kg -1 ) / content of Cd (Se) in the whole plant (mg·kg -1 ).

[0046] Data processing was performed using Excel 2012, data statistical analysis was carried out using SPSS 23.0, and graphs were plotted using Origin 8.

[0047] 2. Results and Conclusions

[0048] (1) Effects of different multiple cadmium-reducing and selenium-enriching stabilization materials on the cadmium-reducing and selenium-enriching effects of rice

[0049] The results of the effects of different multi-functional cadmium-reducing and selenium-enriching stabilizing materials on the selenium and cadmium contents in rice are as follows Figure 1 shown. As can be seen from Figure 1 it, applying No. 1-7 multi-functional cadmium-reducing and selenium-enriching stabilizing materials in the soil all had the effects of reducing cadmium and enriching selenium. After applying the stabilizing materials, the cadmium content in brown rice decreased by 24.14% - 70.59%, and the selenium content increased by 60.31% - 166.49%. Among them, the No. 6 multi-functional cadmium-reducing and selenium-enriching stabilizing material had the best effect of reducing cadmium and enriching selenium. Compared with CK (No. 8, without applying the multi-functional cadmium-reducing and selenium-enriching stabilizing material), the cadmium content in brown rice decreased by 70.59%, and the selenium content increased by 166.49%. Considering comprehensively, the No. 6 multi-functional cadmium-reducing and selenium-enriching stabilizing material had the best effect of reducing cadmium and enriching selenium on rice.

[0050] (2) Effects of different multi-functional cadmium-reducing and selenium-enriching stabilizing materials on the selenium and cadmium enrichment abilities of different parts of rice

[0051] The bioconcentration factor (BCF) is an important index to measure the absorption and accumulation of a certain element in different parts of crops, which reflects the enrichment ability of different parts of crops for a certain element. In order to investigate the effects of different multi-functional cadmium-reducing and selenium-enriching stabilizing materials on the selenium and cadmium enrichment abilities of different parts of rice, different multi-functional cadmium-reducing and selenium-enriching stabilizing materials were applied during the cultivation of rice in this example, and the results are shown in Tables 3 and 4.

[0052] As can be seen from Table 3, in various different treatments, the selenium enrichment ability of rice roots was much greater than that of stems, leaves and rice. Compared with the blank treatment, after applying different multi-functional cadmium-reducing and selenium-enriching stabilizing materials, the selenium enrichment abilities of different parts of rice all increased significantly, especially the effect was the most obvious after applying the No. 6 multi-functional cadmium-reducing and selenium-enriching stabilizing material, and the selenium content in rice was 2.67 times that of CK. This shows that after applying the multi-functional cadmium-reducing and selenium-enriching stabilizing materials in rice cultivation, the selenium content of different parts of rice can be significantly increased, achieving the purpose of selenium-enriched rice cultivation.

[0053] Table 3: Selenium bioconcentration factors of different parts of rice under different treatment methods

[0054]

[0055] Note: Different letters after the data in the same column indicate significant differences among groups after different treatments of crops (p<0.05).

[0056] As can be seen from Table 4, among all different treatments, the cadmium enrichment ability of various parts of rice is in the order of root > stem > leaf > brown rice. This indicates that in rice cultivation, the root has the strongest cadmium enrichment ability from the soil, while the brown rice has the weakest. The results in Table 4 also show that after applying different multiple cadmium-reducing and selenium-enriching stabilizing materials, the cadmium enrichment ability of various parts of rice can be reduced, and the difference is significant compared with the blank control. This shows that after applying different multiple cadmium-reducing and selenium-enriching stabilizing materials, the absorption of cadmium by rice from the soil is significantly reduced, achieving the effect of cadmium reduction. In addition, after applying the No. 6 multiple cadmium-reducing and selenium-enriching stabilizing material, the cadmium enrichment ability of the stem and brown rice of rice is the worst, and the difference is significant compared with other treatments (p < 0.05); after applying the No. 7 multiple cadmium-reducing and selenium-enriching stabilizing material, the cadmium enrichment ability of the leaf of rice is the worst, and the difference is significant compared with other treatments (p < 0.05).

[0057] Table 4: Cadmium enrichment coefficients of various parts of rice under different treatment methods

[0058]

[0059] Note: Different letters after the data in the same column indicate significant differences among groups after different treatments of the crops (p < 0.05).

[0060] (3)Effects of different multiple cadmium-reducing and selenium-enriching stabilizing materials on the transport ability of selenium and cadmium in rice

[0061] The transport coefficient (TF) represents the ratio of the content of a certain element in organ A and organ B in a plant, and can reflect the transport ability of the plant to a certain element. To investigate the effects of different multiple cadmium-reducing and selenium-enriching stabilizing materials on the transport ability of selenium and cadmium in rice, different multiple cadmium-reducing and selenium-enriching stabilizing materials were applied during rice cultivation in this example, and the results are shown in Table 5. As can be seen from Table 5, compared with CK, the application of the No. 2, 3, 4, 6, and 7 multiple cadmium-reducing and selenium-enriching stabilizing materials all improved the ability of selenium transport from roots to stems and leaves. Among them, the No. 6 multiple cadmium-reducing and selenium-enriching stabilizing material increased the proportion of selenium transport from the roots to the stems and leaves of rice by 60.00%. After applying the No. 1 - 5 and 7 multiple cadmium-reducing and selenium-enriching stabilizing materials, the ability of selenium transport from stems and leaves to brown rice of rice was also improved compared with the blank group. In the treatment with the No. 1 multiple cadmium-reducing and selenium-enriching stabilizing material, the TF of selenium increased by 36.59%, which was significantly different from other treatments (P < 0.05). Compared with the CK treatment, in the treatments with the No. 4, 5, and 6 multiple cadmium-reducing and selenium-enriching stabilizing materials, the ability of cadmium transport from roots to stems and leaves was weakened. Among them, the transport coefficients of the No. 5 and 6 were 0.08, which were significantly different from other treatments (P < 0.05). Compared with CK, in the treatments with the No. 2, 4, 6, and 7 multiple cadmium-reducing and selenium-enriching stabilizing materials, the ability of cadmium transport from stems and leaves to brown rice showed a decrease. Among them, the treatment effect of the No. 2 multiple cadmium-reducing and selenium-enriching stabilizing material was the most significant (p < 0.05).

[0062] Table 5: Selenium and cadmium transport coefficients in different parts of rice under different treatment methods

[0063]

[0064] Note: Different letters after the data in the same column indicate significant differences among groups after different treatments on the crop (p < 0.05).

[0065] (4)Effect of different multi - heavy cadmium - reducing and selenium - enriching stabilization materials on the distribution of selenium and cadmium in different parts of rice

[0066] The results of the effect of different multi - heavy cadmium - reducing and selenium - enriching stabilization materials on the distribution of selenium in different parts of rice are as Figure 2 shown. As Figure 2 can be seen, there are significant differences in the distribution coefficients of selenium in different parts of rice under different treatments. However, generally speaking, the order of the distribution coefficients of selenium in the root, stem, leaf, and brown rice of rice is root > leaf > stem > brown rice. The selenium content in the root is significantly higher than that in other parts, while the selenium content in the stem, leaf, and grain is relatively low. Among different treatments, after applying the No. 5 multi - heavy cadmium - reducing and selenium - enriching stabilization material, the distribution coefficient of selenium in the root is the largest and the selenium content ratio is the highest, while the distribution coefficient of selenium in the rice is the smallest and the selenium content ratio is the lowest. After applying the No. 6 multi - heavy cadmium - reducing and selenium - enriching stabilization material, the distribution coefficient of selenium in the root is the smallest and the selenium content ratio is the lowest, while the distribution coefficients of selenium in the stem and leaf are the largest and the selenium content ratios are the highest. In addition, when comparing the distribution coefficients of selenium in the same part under different treatment conditions, compared with CK, after applying the No. 1 - 4, 6, and 7 multi - heavy cadmium - reducing and selenium - enriching stabilization materials, the distribution coefficients of selenium in the brown rice of rice all show an increase, but not very significantly.

[0067] The results of the effect of different multi - heavy cadmium - reducing and selenium - enriching stabilization materials on the distribution of cadmium in different parts of rice are as Figure 3 shown. As Figure 3 can be seen, there are also significant differences in the distribution coefficients of cadmium in different parts of rice under different treatments. In each different treatment, the distribution coefficients of cadmium in the root, stem, leaf, and brown rice of rice are all in the order of root > stem > leaf > brown rice. The distribution coefficient of cadmium in the root is significantly higher than that in other parts, and the distribution coefficients of cadmium in the stem, leaf, and brown rice gradually decrease, but the gap is not obvious, and the distribution coefficient of cadmium in the rice is the smallest.

[0068] (5)Effect of different multi - heavy cadmium - reducing and selenium - enriching stabilization materials on the agronomic traits of rice

[0069] To investigate the effects of different multiple cadmium-reducing and selenium-enriching stabilization materials on the agronomic traits of rice, in this example, the 1000-grain weight (test object: air-dried and unhusked rice grains) and seed setting rate of rice grains were studied, and the results are shown in Table 6. As can be seen from Table 6, compared with CK, after applying the 1st, 2nd, and 4th - 7th multiple cadmium-reducing and selenium-enriching stabilization materials, the 1000-grain weight and seed setting rate of rice increased. Among them, the 1000-grain weight and seed setting rate of rice treated with the 7th multiple cadmium-reducing and selenium-enriching stabilization material were the best, and the differences in the 1000-grain weight and seed setting rate after the 6th and 7th treatments were significant compared with other treatments (P < 0.05). This fully shows that after applying the 1st - 7th multiple cadmium-reducing and selenium-enriching stabilization materials, not only can the function of selenium enrichment and cadmium reduction be achieved, but also the yield of rice can be increased.

[0070] Table 6: Effects of different treatment methods on the agronomic traits of rice

[0071]

[0072] Note: Different letters after the data in the same column indicate significant differences among groups after different treatments of the crops (p < 0.05)

[0073] Example 3: Effects of multiple cadmium-reducing and selenium-enriching stabilization materials on the absorption of selenium and cadmium and agronomic traits of dryland crops

[0074] 1. Experimental method

[0075] Dryland crops were cultivated in pots, and the experiment was carried out in the Experimental Engineering Center of Hubei Minzu University, simulating field cultivation in an open-air manner. Pakchoi and Chinese flowering cabbage were used for the experiment on dryland crops to screen different multiple cadmium-reducing stabilization materials. All experiments used the above-mentioned surface soil (collection depth 0 - 20 cm). The plastic pots used in the experiment had a diameter of 32 cm and a height of 25 cm, and 8 kg of soil was used in each pot. Eight treatment methods were set for pakchoi and Chinese flowering cabbage, corresponding to the 7 multiple cadmium-reducing and selenium-enriching stabilization materials in Example 1 (treatment methods 1 - 7) and 1 blank (CK) control (treatment method 8), and 3 replicates were set for each treatment. In all experiments, the multiple cadmium-reducing and selenium-enriching stabilization materials were applied as base fertilizers into the soil at one time and mixed evenly, and 4.6 g of the stabilization material was applied to each pot. The blank control experiment was carried out with reference to the corresponding treatment, replacing the multiple cadmium-reducing and selenium-enriching stabilization materials with the corresponding amounts of nitrogen, phosphorus, and potassium fertilizers. Pakchoi and Chinese flowering cabbage were watered with deionized water after sowing to keep the soil surface layer of 0 - 20 cm moist. During the planting process, attention should be paid to the prevention and control of pests and diseases. After harvesting, taking the selenium and cadmium contents in pakchoi and Chinese flowering cabbage as indicators, the effects of different multiple cadmium-reducing and selenium-enriching stabilization materials on cadmium reduction and selenium enrichment of dryland crops were compared, and the multiple cadmium-reducing and selenium-enriching stabilization material with the best cadmium reduction and selenium enrichment effect on dryland crops was screened out.

[0076] For pakchoi, it is harvested 50 days after sowing when the plant height reaches 25 cm; for baby bok choy, it is harvested 60 days after sowing when the plant height reaches 25 cm. The harvested samples are washed clean with tap water, then washed twice with deionized water, blanched at 105 °C for 30 min, dried at 70 °C to constant weight, pulverized and sieved (100 mesh) for later use.

[0077] The detection method and data processing are the same as those in Example 2.

[0078] 2. Results and Conclusions

[0079] (1) Effects of different multi-functional cadmium-reducing and selenium-enriching stabilization materials on cadmium reduction and selenium enrichment in pakchoi

[0080] As Figure 4 can be seen, the cadmium content in pakchoi under different treatment methods is significantly lower than that in the CK treatment. Among them, the treatment with the 7th multi-functional cadmium-reducing and selenium-enriching stabilization material has the best cadmium reduction effect on pakchoi, and the cadmium reduction ratio reaches 44.76% compared with the blank control treatment. In addition, the treatment with the 6th multi-functional cadmium-reducing and selenium-enriching stabilization material has the best selenium enrichment effect. Compared with the blank control treatment, the increase ratio of selenium content in pakchoi reaches 136.82%.

[0081] (2) Effects of different multi-functional cadmium-reducing and selenium-enriching stabilization materials on cadmium reduction and selenium enrichment in baby bok choy

[0082] As Figure 5 can be seen, the cadmium content in baby bok choy treated with the 1st - 7th multi-functional cadmium-reducing and selenium-enriching stabilization materials is lower than that in the blank control. The cadmium content in baby bok choy treated with the 6th and 7th multi-functional cadmium-reducing and selenium-enriching stabilization materials is the lowest, and the cadmium reduction ratio of baby bok choy reaches about 35%. In addition, after applying the 6th multi-functional cadmium-reducing and selenium-enriching stabilization material, the selenium enrichment effect of baby bok choy is the best, and the selenium enrichment ratio of baby bok choy reaches 74.12%.

[0083] (3) Effects of different multi-functional cadmium-reducing and selenium-enriching stabilization materials on the agronomic traits of pakchoi and baby bok choy

[0084] To investigate the effects of different multi - heavy cadmium - reducing and selenium - enriching stabilization materials on the agronomic traits of pakchoi and Chinese flowering cabbage, in this example, the mass of the above - ground parts of pakchoi and the mass of the above - ground parts of Chinese flowering cabbage (both pakchoi and Chinese flowering cabbage were weighed immediately after fresh picking) were studied, and the results are shown in Table 7. As can be seen from Table 7, for pakchoi, compared with CK, the single - plant mass increased in the treatments with the application of No. 1 - 7 multi - heavy cadmium - reducing and selenium - enriching stabilization materials; compared with the blank control, the single - plant mass of pakchoi showed significant differences (P < 0.05) after the treatment with No. 4 - 7 multi - heavy cadmium - reducing and selenium - enriching stabilization materials, while the single - plant mass of pakchoi showed no significant differences (P > 0.05) after the treatment with No. 1 - 3 multi - heavy cadmium - reducing and selenium - enriching stabilization materials. For Chinese flowering cabbage, compared with the blank control, the single - plant mass also increased in the treatments with the application of No. 1 - 7 multi - heavy cadmium - reducing and selenium - enriching stabilization materials; among these 7 treatments, except for the treatments with No. 1 - 3 multi - heavy cadmium - reducing and selenium - enriching stabilization materials showing no significant differences (P > 0.05), the other 4 treatments with multi - heavy cadmium - reducing and selenium - enriching stabilization materials showed significant differences (P < 0.05). This fully shows that after the application of No. 1 - 7 multi - heavy cadmium - reducing and selenium - enriching stabilization materials, not only can the function of selenium - enriching and cadmium - reducing be achieved, but also the yields of pakchoi and Chinese flowering cabbage are improved.

[0085] Table 7: Effects of different treatment methods on the agronomic traits of pakchoi and Chinese flowering cabbage

[0086]

[0087] Note: Different letters after the data in the same column indicate significant differences among groups after different treatments of the crops (p < 0.05)

[0088] The research results of the present invention show that under 8 treatment methods, the selenium content in the roots is significantly higher than that in other parts. Comparing the selenium - enriching ratios of various multi - heavy cadmium - reducing and selenium - enriching stabilization materials for paddy field crops (rice) and dry - land crops (pakchoi, Chinese flowering cabbage), the selenium - enriching ratio of the edible parts of dry - land crops is higher than that of paddy field crops due to the difference in the edible parts of the crops. In addition, in the present invention, compared with CK, the treatments with the addition of No. 1 - 7 multi - heavy cadmium - reducing and selenium - enriching stabilization materials all increased the selenium enrichment coefficient of the crops, but the selenium - enriching effect of No. 6 multi - heavy cadmium - reducing and selenium - enriching stabilization material is relatively better.

[0089] After applying the multiple cadmium-reducing and selenium-enriching stabilization materials of the present invention, whether it is paddy field crops or dry land crops, the cadmium-reducing effect is very significant. Relatively speaking, after applying the multiple cadmium-reducing and selenium-enriching stabilization materials No. 4 to No. 7, the cadmium-reducing effect on crops is more obvious. Comparing the cadmium-reducing ratios of various multiple cadmium-reducing and selenium-enriching stabilization materials for paddy field crops (rice) and dry land crops (pakchoi, Chinese spinach), the cadmium-reducing effect of the multiple cadmium-reducing and selenium-enriching stabilization materials on paddy field crops is better. After applying the multiple cadmium-reducing and selenium-enriching stabilization materials, the cadmium content in each part of the rice at maturity is root > stem > leaf > brown rice, and the cadmium content in the root is significantly higher than that in other parts. The experimental results of the present invention show that the multiple cadmium-reducing and selenium-enriching stabilization materials No. 6 and No. 7 have a better cadmium-reducing effect than other treatments, and have an obvious cadmium-reducing effect on each part of the three crops in this test, especially for rice.

[0090] To sum up, (1) After applying different multiple cadmium-reducing and selenium-enriching stabilization materials to high-cadmium and selenium-enriched soil, they all have the effect of selenium enrichment and cadmium reduction. Among them, the multiple cadmium-reducing and selenium-enriching stabilization material No. 6 has a good effect on cadmium reduction and selenium enrichment of rice, selenium enrichment of pakchoi, and cadmium reduction and selenium enrichment of Chinese spinach, and the multiple cadmium-reducing and selenium-enriching stabilization material No. 7 has a good cadmium-reducing effect on pakchoi and Chinese spinach. (2) The selenium enrichment and cadmium reduction effect of the multiple cadmium-reducing and selenium-enriching stabilization materials on paddy field crops (rice) is better than that on dry land crops (pakchoi, Chinese spinach). (3) After applying the multiple cadmium-reducing and selenium-enriching stabilization materials to the soil, both paddy field crops and dry land crops have an increased yield. Among them, the multiple cadmium-reducing and selenium-enriching stabilization material No. 7 has the best yield-increasing effect on rice, and the multiple cadmium-reducing and selenium-enriching stabilization material No. 6 has the best yield-increasing effect on pakchoi and Chinese spinach.

Claims

1. A multiple cadmium-reducing and selenium-enriching stabilized material, characterized in that: It is composed of the following components in percentage by mass: astragalus 48%, sodium selenite 0.5%, diammonium hydrogen phosphate 40%, quicklime 11.5%; The Chinese astragalus is the above-ground part of Chinese astragalus, which can be obtained by harvesting the above-ground part of Chinese astragalus, drying it in the sun and then crushing it.

2. A multiple cadmium-reducing and selenium-enriching stabilized material, characterized in that: It is composed of the following components in percentage by mass: astragalus 40%, sodium selenite 0.5%, potassium sulfide 8%, diammonium hydrogen phosphate 40%, quicklime 11.5%; The Chinese astragalus is the above-ground part of Chinese astragalus, which can be obtained by harvesting the above-ground part of Chinese astragalus, drying it in the sun and then crushing it.

3. A method for preparing the multi-cadmium-reduced selenium-rich stabilized material according to claim 1 or 2, characterized in that: The following steps are involved: (1) Harvest the above-ground part of the Chinese astragalus, dry it in the sun and then crush it; (2) Weigh the astragalus obtained in step (1) and other raw materials according to the formula and mix them evenly.

4. Use of the multiple cadmium-reducing and selenium-enriching stabilization material according to claim 1 or 2 in crop planting.

5. Use of the multiple cadmium-reducing and selenium-enriching stabilized material according to claim 1 or 2 in the cultivation of rice, Chinese cabbage and / or Brassica juncea.

6. The use according to claim 4, characterized in that: The application is: before planting crops, the multiple cadmium-reducing and selenium-enriching stabilization materials are applied to the soil as base fertilizer at one time and mixed evenly.

7. The use according to claim 5, characterized in that: The application is: before planting crops, the multiple cadmium-reducing and selenium-enriching stabilization materials are applied to the soil as base fertilizer at one time and mixed evenly.

Images