Zinc-rich cadmium-reducing leaf surface blocking and controlling agent as well as preparation method and application method thereof

Abstract

The invention relates to the technical field of agriculture, in particular to a zinc-rich cadmium-reducing leaf surface blocking and controlling agent as well as a preparation method and an application method thereof. According to the specific technical scheme, the zinc-rich cadmium-reducing leaf surface blocking and controlling agent is prepared from, by mass, 10%-20% of gamma-chitosan, 20%-30% of L-malic acid and 50%-70% of zinc sulfate. The technical problem that in the prior art, the cadmium content of brown rice cannot be reduced through a leaf surface blocking and controlling agent is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of agricultural technology, in particular to a zinc-rich and cadmium-reducing foliar control agent and its preparation method and application method. BACKGROUND

[0002] Rice is an important global food resource, and more than half of the world's population relies on rice as their main food. The quality of rice is affected by the trace elements in the rice, such as zinc, iron, cadmium, silicon, etc. These trace elements account for a very small proportion of all the elements needed during the growth cycle of rice, but they are indispensable for the growth of rice.

[0003] Cadmium is one of the most toxic pollutants recognized at present, and it is a non-essential element with unknown biological function. It cannot be biodegraded and thus easily accumulates in the environment. Cadmium also has strong solubility and mobility, and is easily absorbed by plants. The high mobility of cadmium in the soil-rice system enables it to accumulate in large amounts in rice and be transported to the grain, ultimately leading to the problem of cadmium rice. Cadmium has a half-life of 10-30 years in the body, and its toxicity manifests as a variety of syndromes, including anemia, high blood pressure, heart failure, liver and lung damage, and kidney failure.

[0004] The Food and Agriculture Organization of the United Nations and the World Health Organization have determined that the maximum monthly intake of cadmium by the human body is 25mg / kg. In order to reduce the risk of cadmium pollution in rice to human health, the food safety standard (GB2762-2012) of our country stipulates that the cadmium content in rice should not be higher than 0.2mg / kg.

[0005] Normal adults need to supplement 10-15mg of zinc per day to prevent biological membrane damage caused by changes in the structure of fatty acid components and maintain cell membrane function. Zinc also helps reduce the risk of cancer of digestive system organs and inhibits the carcinogenicity of carcinogens. If the human body is in a state of zinc deficiency for a long time, multiple systemic organs may be damaged, leading to disease. In addition, the function of immune cells and immune organs in the human body also depends on the participation of zinc elements. When the human body is deficient in zinc, the activity of enzymes and cells in the human body is affected, causing NT cells, T cells and macrophages to functionally decline, reducing the activity of nucleoside phosphorus oxygenase, and even leading to the death of myeloid-derived cells and lymphocytes, reducing the body's immunity, and increasing the body's susceptibility to pathogenic bacteria such as bacteria and viruses. Zinc deficiency can also cause oral ulcers. Spraying zinc-containing foliar control agents during the growth of rice is an effective way to increase the zinc content of rice, and in cadmium-polluted areas, the development of foliar control agents that both enrich zinc and reduce cadmium content in rice is of great significance to rice production. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a zinc-rich cadmium-reducing foliar control agent, and a preparation method and application method thereof, which solve the technical problem that rice cannot reduce the cadmium content in brown rice by using a foliar control agent in the prior art.

[0007] To achieve the above object, the present application is implemented by the following technical solutions: The present application discloses a zinc-rich cadmium-reducing foliar control agent, which comprises 10-20% of gamma-chitosan, 20-30% of L-malic acid and 50-70% of zinc sulfate according to the mass percentage.

[0008] Correspondingly, a preparation method of the zinc-rich cadmium-reducing foliar control agent is provided, wherein gamma-chitosan is dissolved in water, stirred in a 95℃ water bath until no particles are present, then cooled to room temperature, L-malic acid is added, ultrasonically treated until no obvious particles are present in the suspension, and finally zinc sulfate is added, stirred at room temperature until no obvious particles are present in the suspension, thereby obtaining the zinc-rich cadmium-reducing foliar control agent.

[0009] Correspondingly, an application method of the zinc-rich cadmium-reducing foliar control agent is provided, wherein the zinc-rich cadmium-reducing foliar control agent is sprayed at a rate of 1500L / ha during the growth of rice, the spraying time is before 10am on a sunny or cloudy day without wind, the spraying temperature is 15-30℃, and the spraying site is the rice leaf surface.

[0010] Preferably, the concentration of the diluted zinc-rich cadmium-reducing foliar control agent is 2-8mmol / L.

[0011] Preferably, the zinc-rich cadmium-reducing foliar control agent is sprayed during the booting stage and the grain filling stage of rice, and the spraying frequency is 3 times.

[0012] The present application has the following advantages: The zinc-rich cadmium-reducing foliar control agent provided by the present application is prepared by compounding gamma-chitosan, L-malic acid and zinc sulfate, and is sprayed during the booting stage and the grain filling stage of rice. Compared with spraying an equal amount of water and a single formula of rice foliar control agent, the zinc-rich cadmium-reducing foliar control agent of the present application significantly reduces the cadmium content in brown rice and increases the zinc content in brown rice, has the advantages of simple operation, easy access to raw materials, and synergistic effect of the several components of the control agent, and has a strong application prospect. DETAILED DESCRIPTION

[0013] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0014] The technical means used in the examples are conventional means well known to those skilled in the art, unless otherwise specified.

[0015] The application discloses a zinc-rich cadmium-reducing foliar resistance control agent, which comprises 10-20% of gamma-chitosan, 20-30% of L-malic acid and 50-70% of zinc sulfate according to mass percentage. The preparation process is as follows: gamma-chitosan is dissolved in water, stirred in a 95 DEG C water bath kettle by using a turbine stirrer until no particles are present, cooled to room temperature, L-malic acid is added, and an ultrasonic oscillator is used until a suspension without obvious particles is obtained, finally, zinc sulfate is added, and a turbine stirrer is used to stir at room temperature until a suspension without obvious particles is obtained, thereby obtaining the zinc-rich cadmium-reducing foliar resistance control agent.

[0016] The application discloses a method for applying the zinc-rich cadmium-reducing foliar resistance control agent, wherein the zinc-rich cadmium-reducing foliar resistance control agent is sprayed at a dose of 1500 L / ha during the growth of rice, the spraying time is before 10 o'clock in the morning on a sunny or cloudy day without wind, the spraying temperature is 15-30 DEG C, and the spraying position is the rice leaf surface. The concentration of the diluted zinc-rich cadmium-reducing foliar resistance control agent is 2-8 mmol / L. The zinc-rich cadmium-reducing foliar resistance control agent is sprayed for 3 times during the booting stage and the grain filling stage of the rice.

[0017] The application will be further described below in combination with specific examples.

[0018] Example 1 1.43775 g of zinc sulfate, 0.67045 g of L-malic acid and 0.5 g of gamma-chitosan are dissolved in ultrapure water to obtain a suspension without obvious particles by vortex stirring, oscillation and other methods, thereby obtaining the zinc-rich cadmium-reducing foliar resistance control agent, which is referred to as the material hereinafter.

[0019] Spraying period effect verification test: field plot tests of different foliar resistance control agents for early rice are carried out.

[0020] The test process is as follows: the material is sprayed on the rice by using a small spray bottle according to the scheme time and scheme amount, and the control is sprayed with an equal amount of water.

[0021] Test site: Huanggu Village, Liling City Test time: early rice season in 2024 Test setting: three plots are set for each treatment, and three parallels are set when the element content is determined for each plot. The area of each plot is 2 square meters (i.e., 300 mL of the zinc-rich cadmium-reducing foliar resistance control agent for each plot, and an equal amount of water for the control group), and the plots are isolated by empty rows. All plots are in the same field, and the growth environment and fertilizer application are completely consistent.

[0022] Test field plot: the total cadmium content of the soil was 0.57 ± 0.10 mg / kg, and the rice variety was uniform, which was a local main variety.

[0023] Test treatment one: at the early rice booting stage and grain filling stage, 5 mmol / L of the present material (300 mL) was sprayed on the rice leaves by using a small-sized spray pot; the control was spraying an equal amount of water.

[0024] Test treatment two: at the early rice booting stage and grain filling stage, 5 mmol / L of L-malic acid (300 mL) was sprayed on the rice leaves by using a small-sized spray pot; the control was spraying an equal amount of water.

[0025] Test treatment three: at the early rice booting stage and grain filling stage, 5 mmol / L of γ-chitosan (300 mL) was sprayed on the rice leaves by using a small-sized spray pot; the control was spraying an equal amount of water.

[0026] Test treatment four: at the early rice booting stage and grain filling stage, 5 mmol / L of zinc sulfate (300 mL) was sprayed on the rice leaves by using a small-sized spray pot; the control was spraying an equal amount of water.

[0027] Sample collection: at the mature stage of the rice (mid-to late July), the rice grains were collected, threshed, and hulled.

[0028] The test results are as follows: (1) The test results of the cadmium content and the zinc content in the brown rice are shown in Table 1, and the results show that, compared with spraying an equal amount of water, spraying the zinc-rich cadmium-reducing foliar control agent of the present application, γ-chitosan, L-malic acid, and zinc sulfate all significantly reduced the cadmium content in the brown rice and increased the zinc content in the brown rice, among which the zinc-rich cadmium-reducing foliar control agent of the present application had the most significant effect, and the cadmium reduction effect was 58.73% compared with spraying an equal amount of water. Compared with other single foliar control agents, the effect of the present material on reducing the cadmium content in the brown rice was significantly better than that of the single foliar control agent, and the zinc element was slightly increased.

[0029] Table 1 Test results of spraying different materials

[0030] (2) The transport of cadmium in the rice body is shown in Table 2. The test results show that, compared with spraying the same amount of water, spraying the zinc-rich cadmium-reducing foliar control agent, γ-chitosan, L-malic acid and zinc sulfate of the application all reduce the transport of cadmium from the stem base to the stem and leaves. For the transport of cadmium from the stem and leaves to the axis, the material shows the best effect, with a transport coefficient of 0.156±0.008, which fixes more cadmium in the stem and leaf part and reduces the upward transport capacity of cadmium. For the transport of cadmium from the axis to the shell, the material shows the best effect, with a transport coefficient of 0.143±0.049, which fixes more cadmium in the axis part. For the transport of cadmium from the shell to the grain, the zinc-rich cadmium-reducing foliar control agent of the application shows the best effect, with a transport coefficient of 0.448±0.128. Compared with other single foliar control agents, after spraying the material, the transport of cadmium from the stem and leaves to the axis and the axis to the shell shows the lowest transport coefficient, which is better than the single foliar control agent.

[0031] Table 2 Transport coefficient of cadmium in rice body

[0032] 3. The proportion of cadmium in the leaves is shown in Table 3. The test results show that, compared with spraying the same amount of water, spraying the zinc-rich cadmium-reducing foliar control agent, γ-chitosan, L-malic acid and zinc sulfate of the application all significantly reduces the proportion of cadmium content in the soluble components of leaf cells, increases the proportion of cadmium content in the cell wall and organelle components, and fixes more cadmium in the cell wall and organelle. When cadmium is fixed by the cell wall and organelle of the leaf cell, it can effectively reduce the transport of cadmium in the cell, and the cell wall is the main part of fixing cadmium. After spraying the material, compared with other single foliar control agents, the material can effectively increase the proportion of cadmium in the cell wall component, which is 44.70%±0.59%, and effectively reduce the proportion of cadmium content in the soluble component, which is 29.90%±0.50%. The material has a much higher effect than other single foliar control agents in reducing the transport capacity of cadmium in the rice body.

[0033] Table 3 Proportion of cadmium in leaves

[0034] 4. The effect of the leaf surface control agent on chlorophyll in the leaves is shown in Table 4. The test results show that, compared with spraying the same amount of water, spraying the zinc-rich and cadmium-reducing leaf surface control agent, γ-chitosan, L-malic acid and zinc sulfate of the present application all increase the contents of chlorophyll a, chlorophyll b and total chlorophyll in the rice leaves. The increase in chlorophyll content helps to increase the yield of rice. The effect of the present material on the increase of chlorophyll a, chlorophyll b and total chlorophyll is better than that of other single type of leaf surface control agent. After spraying, the contents of chlorophyll a, chlorophyll b and total chlorophyll are 2.215±0.041 mg / g, 0.581±0.152 mg / g and 2.796±0.193 mg / g, respectively.

[0035] Table 4. Effect of leaf surface control agent on chlorophyll in leaves

[0036] According to the test results of the above test examples, in the zinc-rich and cadmium-reducing leaf surface control agent of the present application, the γ-chitosan, L-malic acid and zinc sulfate components can mutually cooperate and significantly reduce the cadmium content and significantly increase the zinc content in the rice brown rice through the synergistic effect. Compared with other single leaf surface control agent formulations, the zinc-rich and cadmium-reducing leaf surface control agent of the present application has extremely outstanding effects in reducing the cadmium content and increasing the zinc content in brown rice, and solves the technical problem that rice cannot reduce the cadmium content in brown rice by using a leaf surface control agent in the prior art.

[0037] 5. The effect of the leaf surface control agent on yield is shown in Table 5. The test results show that, compared with spraying the same amount of water, spraying the zinc-rich and cadmium-reducing leaf surface control agent and γ-chitosan of the present material both increase the yield of rice, but L-malic acid treatment reduces the yield of rice. Compared with single leaf surface control agent, the present material has the best effect on increasing the yield, and the yield of rice reaches 94224.6±2913.8 kg / ha after application, which is 2 times the yield of rice compared with the same amount of water.

[0038] Table 5. Effect of leaf surface control agent on yield of rice

[0039] The above examples only describe the preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A zinc-enriched cadmium-reducing foliar barrier control agent, characterized by: According to the mass percentage, it comprises 10%-20% of gamma-chitosan, 20%-30% of L-malic acid and 50%-70% of zinc sulfate.

2. The preparation method of the zinc-rich cadmium-reducing foliar control agent of claim 1, characterized in that: The gamma-chitosan is dissolved in water, stirred in a 95℃ water bath until no particles, then cooled to room temperature, added with L-malic acid, ultrasonically treated until no obvious particle suspension, finally added with zinc sulfate, stirred at room temperature until no obvious particle suspension, thus obtaining the zinc-rich and cadmium-reducing foliar control agent.

3. The method for applying the zinc-enriched cadmium-reducing foliar control agent of claim 1, characterized in that: During the growth of rice, the zinc-rich and cadmium-reducing foliar control agent is sprayed at 1500L per hectare, the spraying time is before 10am on sunny or cloudy day without wind, the spraying temperature is 15-30℃, and the spraying position is the rice leaf surface.

4. The method of applying according to claim 3, wherein: The concentration of the diluted zinc-rich and cadmium-reducing foliar control agent is 2-8mmol / L.

5. The method of applying according to claim 3, wherein: The zinc-rich and cadmium-reducing foliar control agent is sprayed at the booting stage and the grain filling stage of rice, and the spraying frequency is 3 times.

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