A foliar regulator and its application in reducing arsenic content in rice

Abstract

The application belongs to the field of agricultural surface pollution treatment, and discloses a leaf surface regulating agent and application thereof in reducing arsenic content in rice. The nanoscale sol leaf surface regulating agent formed by degrading chitosan glue with sodium tripolyphosphate and hydrogen peroxide is used to treat the leaf of arsenic contaminated rice, can regulate and reduce the absorption and transport of arsenic in rice during the grain filling stage, increase the arsenic content in rice hull and leaf, reduce the transport of arsenic in soil to grains, so as to reduce the arsenic content in rice.

Description

Technical Field

[0001] This invention belongs to the field of agricultural non-agricultural pollution control, specifically relating to a foliar regulator and its application in reducing arsenic content in rice. Background Technology

[0002] Heavy metal pollution in my country's arable land has become increasingly serious. According to the "National Soil Pollution Status Survey Bulletin" published by the Ministry of Environmental Protection and the Ministry of Land and Resources in 2014, 16% of soil samples (19% of agricultural soils) exceeded my country's environmental quality standards, with the exceedance rate of arsenic (As) at 2.7%. Red soil accounts for 21% of the country's land area, and due to factors such as climate, meteorological conditions, industrial and mining activities, and geological conditions, heavy metal pollution in farmland in red soil areas is particularly severe. 38% of the soil in the Pearl River Delta region exceeds heavy metal standards, and 22% of rice samples exceed arsenic standards. Rice is a major food crop in my country, with an annual output of approximately 200 million tons and an annual consumption of 140 million tons. The average daily arsenic intake from rice in my country is 25.20 μg / day. Therefore, it is urgent to find effective methods to reduce the harm caused by As pollution in rice.

[0003] Currently, the main remediation measures for heavy metal pollution in farmland soil include physical, biological, and chemical remediation. However, these methods are often limited in their application and promotion due to the high investment and low effectiveness required for large-scale soil pollution control. In recent years, improving plants' resistance to heavy metals to reduce their absorption has become a new approach to heavy metal pollution control in soil. This method is both economical and safe. Literature reports that foliar spraying can reduce the absorption and accumulation of heavy metals such as arsenic in rice, thus improving its resistance to heavy metals. Foliar inhibitors containing metal elements promote the synthesis of chlorophyll and heavy metal complexes such as glutathione and metallothionein, induce increased activity of POD and CAT, reduce the damaging effect on membrane lipids, and enhance plant resistance to heavy metals. Foliar inhibitors containing non-metallic elements such as silicon, phosphorus, and selenium mainly work by regulating plant physiological processes, enhancing the function of the plant's antioxidant system, increasing the chlorophyll content in crop leaves and promoting photosynthesis, promoting the absorption of nutrients by crops, and reducing cell membrane permeability, thus maintaining the integrity of the membrane system and increasing the crop's resistance to heavy metals.

[0004] Currently, there are many patent documents on rice foliar conditioning, but most rice foliar conditioning products on the market are foliar fertilizers, which have the following problems: first, they contain high levels of chemical substances, posing a potential risk of secondary pollution; second, they have low conversion rates for agricultural products and high usage costs; and third, the application of foliar fertilizers poses a risk of burning the plants, and excessive application can damage the crops, resulting in poor safety. Summary of the Invention

[0005] In view of the deficiencies of the rice foliar conditioning components involved in the prior art, the present invention will provide a foliar regulator and its application in reducing the arsenic content in rice.

[0006] To achieve the above objectives, the following technical solutions are specifically included:

[0007] A method for preparing a foliar regulator includes the following steps:

[0008] (1) Hydrogen peroxide solution was added to chitosan acetic acid solution to carry out hydrogenolysis reaction to obtain degraded chitosan solution;

[0009] (2) Add sodium tripolyphosphate solution to the degraded chitosan solution to carry out sol-gel reaction, and then add water to dilute to obtain the leaf surface regulator.

[0010] A nanoscale sol-based foliar regulator was developed by combining sodium tripolyphosphate with hydrogen peroxide to degrade chitosan. This nanoscale sol-based chitosan is superior to pure chitosan as a foliar regulator for reducing arsenic content in rice.

[0011] In a preferred embodiment of the present invention, the mass ratio of chitosan to acetic acid solution in the chitosan-acetic acid solution is 1 g:(25-30 mL), and the mass concentration of acetic acid is 2-4%.

[0012] In a preferred embodiment of the present invention, the mass concentration of the hydrogen peroxide solution is 4-6%.

[0013] In a preferred embodiment of the present invention, the volume ratio of the hydrogen peroxide solution to the chitosan acetic acid solution is 0.2-1.

[0014] In a preferred embodiment of the present invention, the temperature of the hydrogenolysis reaction is 55-65°C, and the time of the hydrogenolysis reaction is 3-6 hours.

[0015] In a preferred embodiment of the present invention, the stirring rate of the hydrogenolysis reaction is 300-350 rpm.

[0016] In a preferred embodiment of the present invention, the concentration of the sodium tripolyphosphate solution is 0.5-1.5 mg / mL.

[0017] In a preferred embodiment of the present invention, the volume ratio of the degraded chitosan solution to the sodium tripolyphosphate solution is 5:(1-2).

[0018] In a preferred embodiment of the present invention, the pH value of the sodium tripolyphosphate solution is 7-9.

[0019] In a preferred embodiment of the present invention, the sol-gelation reaction time is 0.2-1 h.

[0020] In a preferred embodiment of the present invention, the temperature of the sol-gel reaction is 30-40°C.

[0021] In a preferred embodiment of the present invention, the dilution factor is 10-30 times.

[0022] The application of a foliar regulator in reducing arsenic content in rice includes the following steps:

[0023] First, fertilize, till, and flood the arsenic-contaminated paddy field soil; then plant or transplant rice seedlings. When the rice reaches the grain-filling stage, spray the foliar regulator 1-4 times, 0.3-0.4 liters / square meter each time, with an interval of 3-5 days between each application. Allow the paddy field soil to dry naturally during and after the rice's waxy ripening stage until the rice is harvested.

[0024] Chitosan, a natural substance in the foliar regulator of this invention, possesses characteristics such as biodegradability, high permeability, and the ability to increase crop yield. The nano-sized chitosan of this invention promotes seed germination, plant growth, and inhibits fungal infection. The nano-sized chitosan of this invention has abundant functional groups such as amine (-NH2) and hydroxyl (-OH), which can carry trace elements to form stable and highly soluble biopolymers, acting on plant aerial organs to promote plant growth and shorten the growth cycle through foliar regulation. The nano-sized chitosan foliar regulator of this invention has better bioavailability and physiological enhancement effects, and also has advantages such as low toxicity, good biocompatibility with animal tissues, non-toxicity, no residue, low environmental pollution, and high bioavailability.

[0025] In a preferred embodiment of the present invention, the base fertilizer includes urea, KH2PO4, and K2SO4 in a mass ratio of N:P2O5:K2O = 0.15:0.15:0.10 (g·kg). -1 ).

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention utilizes a nano-sized sol-gel leaf regulator formed by the cementation of sodium tripolyphosphate and chitosan degraded by hydrogen peroxide to treat arsenic-contaminated rice leaves. It can regulate and reduce the absorption and translocation of arsenic in rice grains during the grain-filling stage, increase the arsenic content in rice husks and leaves, and reduce the translocation of arsenic from the soil to the grains, thereby reducing the arsenic content in rice. Attached Figure Description

[0028] Figure 1 The bar chart shows the arsenic content in rice husks of different rice plants in Examples 1-2 and the control group. CK represents the control group sprayed with the same dose of deionized water, and TK represents Examples 1-2 treated with foliar spraying of nano-chitosan.

[0029] Figure 2 The bar chart shows the arsenic content of rice in different rice plants from Examples 1-2 and the control group. CK represents the control group sprayed with the same dose of deionized water, and TK represents Examples 1-2 treated with foliar spraying of nano-chitosan.

[0030] Figure 3 The bar chart shows the arsenic content in the leaves of different rice plants in Examples 1-2 and the control group. CK represents the control group sprayed with the same dose of deionized water, and TK represents Examples 1-2 treated with foliar spraying of nano-chitosan.

[0031] Figure 4 The bar chart shows the arsenic content in leaves and rice grains of rice plants sprayed with modified chitosan (nano-chitosan leaf regulator) in Example 3 and Comparative Example 1 without chitosan. Detailed Implementation

[0032] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0033] The following examples and comparative examples were conducted using topsoil from 20cm of farmland surrounding the Lianhuashan tungsten mine in Shantou City, Guangdong Province, with a total arsenic content of 104mg / kg.

[0034] Information on rice varieties involved:

[0035] Dryland rice: Zhenghan 10;

[0036] State Farms: State Farm No. 58;

[0037] Buddha Nine O'Chapter: A local variety from Shantou.

[0038] Example 1

[0039] Step 1: Dissolve chitosan in a 3% acetic acid solution at a chitosan to acetic acid solution ratio of 1g:30mL. Place the solution in a water bath at 40-50℃ and stir at 200-250 rpm for 1-2 hours until completely dissolved. Then, raise the water bath temperature to 60℃ and increase the stirring speed to 300-350 rpm. Slowly add 50mL of 5% H2O2 solution dropwise at 1-2 seconds per drop. Continue stirring for 5 hours, then stop. Remove the solution and cool it to 25-30℃ to obtain a yellow or pale yellow degraded chitosan solution.

[0040] Step 2: Take a certain amount of the yellow or pale yellow liquid obtained in Step 1 and place it in a sealed glass container. Place the container on a magnetic stirrer at 30–40°C and stir for 0.5–1 hour at 100–200 rpm to disperse the liquid. Then, slowly add 1 mg / mL of pH 8 sodium tripolyphosphate aqueous solution dropwise at a volume ratio of 5:1.5 (chitosan solution:sodium tripolyphosphate aqueous solution = 5:1.5), continuing stirring for 0.5 hours. Finally, dilute with ultrapure water to a 20-fold concentration to obtain the nano-chitosan leaf surface regulator, and store it in a refrigerator at 4°C.

[0041] Step 3: Before planting or transplanting rice seedlings, fertilize, till, and flood the arsenic-contaminated paddy field soil. The base fertilizer includes urea, KH2PO4, and K2SO4 in a mass ratio of N:P2O5:K2O = 0.15:0.15:0.10 (g·kg). -1 );

[0042] Step 4: Plant rice or transplant dry rice in the arsenic-contaminated paddy soil obtained in Step 3. When the rice reaches the grain-filling stage, spray the leaves twice with the nano-chitosan leaf regulator prepared above, 0.35 liters / square meter each time, with an interval of 4 days between the two applications. Allow the paddy soil to dry naturally during and after the rice wax-ripe stage until the rice is harvested.

[0043] The management methods for fertilization, tilling, flooding, and rice growth (including the grain-filling stage, the waxy ripening stage, and beyond) are the same as those for conventional rice management.

[0044] Example 2

[0045] Step 1: Dissolve chitosan in a 3% acetic acid solution at a chitosan to acetic acid solution ratio of 1g:30mL. Place the solution in a water bath at 40-50℃ and stir at 200-250 rpm for 1-2 hours until completely dissolved. Then, raise the water bath temperature to 60℃ and increase the stirring speed to 300-350 rpm. Slowly add 50mL of 5% H2O2 solution dropwise at 1-2 seconds per drop. Continue stirring for 5 hours, then stop. Remove the solution and cool it to 25-30℃ to obtain a yellow or pale yellow degraded chitosan solution.

[0046] Step 2: Take a certain amount of the yellow or pale yellow liquid obtained in Step 1 and place it in a sealed glass container. Place the container on a magnetic stirrer at 30–40°C and stir for 0.5–1 hour at 100–200 rpm to disperse the liquid. Then, slowly add 1 mg / mL of pH 8 sodium tripolyphosphate aqueous solution dropwise at a volume ratio of 5:1.5 (chitosan solution:sodium tripolyphosphate aqueous solution = 5:1.5), continuing stirring for 0.5 hours. Finally, dilute with ultrapure water to a 20-fold concentration to obtain the nano-chitosan leaf surface regulator, and store it in a refrigerator at 4°C.

[0047] Step 3: Before planting or transplanting rice seedlings, fertilize, till, and flood the arsenic-contaminated paddy field soil. The base fertilizer includes urea, KH2PO4, and K2SO4 in a mass ratio of N:P2O5:K2O = 0.15:0.15:0.10 (g·kg). -1 );

[0048] Step 4: Plant rice or transplant rice seedlings in the arsenic-contaminated paddy soil obtained in Step 3. When the rice reaches the grain-filling stage, spray the leaves twice with the nano-chitosan leaf regulator prepared above, 0.35 liters / square meter each time, with an interval of 4 days between the two applications. Allow the paddy soil to dry naturally during and after the rice wax-ripe stage until the rice is harvested.

[0049] The management methods for fertilization, tilling, flooding, and rice growth (including the grain-filling stage, the waxy ripening stage, and beyond) are the same as those for conventional rice management.

[0050] Example 3

[0051] Step 1: Dissolve chitosan in a 3% acetic acid solution at a chitosan to acetic acid solution ratio of 1g:30mL. Place the solution in a water bath at 40-50℃ and stir at 200-250 rpm for 1-2 hours until completely dissolved. Then, raise the water bath temperature to 60℃ and increase the stirring speed to 300-350 rpm. Slowly add 50mL of 5% H2O2 solution dropwise at 1-2 seconds per drop. Continue stirring for 5 hours, then stop. Remove the solution and cool it to 25-30℃ to obtain a yellow or pale yellow degraded chitosan solution.

[0052] Step 2: Take a certain amount of the yellow or pale yellow liquid obtained in Step 1 and place it in a sealed glass container. Place the container on a magnetic stirrer at 30–40°C and stir for 0.5–1 hour at 100–200 rpm to disperse the liquid. Then, slowly add 1 mg / mL of pH 8 sodium tripolyphosphate aqueous solution dropwise at a volume ratio of 5:1.5 (chitosan solution:sodium tripolyphosphate aqueous solution = 5:1.5), continuing stirring for 0.5 hours. Finally, dilute with ultrapure water to a 20-fold concentration to obtain the nano-chitosan leaf surface regulator, and store it in a refrigerator at 4°C.

[0053] Step 3: Before planting or transplanting rice seedlings, fertilize, till, and flood the arsenic-contaminated paddy field soil. The base fertilizer includes urea, KH2PO4, and K2SO4 in a mass ratio of N:P2O5:K2O = 0.15:0.15:0.10 (g·kg). -1 );

[0054] Step 4: Plant or transplant Fojiu Zhan rice in the arsenic-contaminated paddy soil obtained in Step 3. When the rice reaches the grain-filling stage, spray the leaves twice with the nano-chitosan leaf regulator prepared above, 0.35 liters / square meter each time, with an interval of 4 days between the two applications. Allow the paddy soil to dry naturally during and after the rice wax-ripe stage until the rice is harvested.

[0055] The management methods for fertilization, tilling, flooding, and rice growth (including the grain-filling stage, the waxy ripening stage, and beyond) are the same as those for conventional rice management.

[0056] Example 4

[0057] Step 1: Dissolve chitosan in a 2% acetic acid solution at a chitosan to acetic acid solution ratio of 1g:25mL. Place the solution in a water bath at 40-50℃ and stir at 200-250 rpm for 1-2 hours until completely dissolved. Then, raise the water bath temperature to 65℃ and increase the stirring speed to 300-350 rpm. Slowly add 100mL of 6% H2O2 solution dropwise at 1-2 seconds per drop. Continue stirring for 6 hours, then stop. Remove the solution and cool it to 25-30℃ to obtain a yellow or pale yellow degraded chitosan solution.

[0058] Step 2: Take a certain amount of the yellow or pale yellow liquid obtained in Step 1 and place it in a sealed glass container. Place the container on a magnetic stirrer at 30–40°C and stir for 0.5–1 hour at 100–200 rpm to disperse the liquid. Then, slowly add 1 mg / mL of pH 7 sodium tripolyphosphate aqueous solution dropwise at a volume ratio of 5:2 (chitosan degradation solution to sodium tripolyphosphate aqueous solution = 5:2), continuing stirring for 1 hour. Finally, dilute with ultrapure water to a 30-fold concentration to obtain the nano-chitosan leaf surface regulator, and store it in a refrigerator at 4°C.

[0059] Step 3: Before planting or transplanting rice seedlings, fertilize, till, and flood the arsenic-contaminated paddy field soil. The base fertilizer includes urea, KH2PO4, and K2SO4 in a mass ratio of N:P2O5:K2O = 0.15:0.15:0.10 (g·kg). -1 );

[0060] Step 4: Plant rice or transplant dry rice in the arsenic-contaminated paddy soil obtained in Step 3. When the rice reaches the grain-filling stage, spray the leaves once with the nano-chitosan leaf regulator prepared above, at a rate of 0.4 liters / square meter each time, with an interval of 3 days between each application. Allow the paddy soil to dry naturally during and after the rice wax-ripe stage until the rice is harvested.

[0061] The management methods for fertilization, tilling, flooding, and rice growth (including the grain-filling stage, the waxy ripening stage, and beyond) are the same as those for conventional rice management.

[0062] Example 5

[0063] Step 1: Dissolve chitosan in a 2% acetic acid solution at a chitosan to acetic acid solution ratio of 1g:30mL. Place the solution in a water bath at 40-50℃ and stir at 200-250 rpm for 1-2 hours until completely dissolved. Then, raise the water bath temperature to 55℃ and increase the stirring speed to 300-350 rpm. Slowly add 30mL of 4% H2O2 solution dropwise at 1-2 seconds per drop. Continue stirring for 3 hours, then stop. Remove the solution and cool it to 25-30℃ to obtain a yellow or pale yellow degraded chitosan solution.

[0064] Step 2: Take a certain amount of the yellow or pale yellow liquid obtained in Step 1 and place it in a sealed glass container. Place the container on a magnetic stirrer at 30–40°C and stir at 100–200 rpm for 0.5–1 h to disperse the liquid. Then, slowly add 1 mg / mL of pH 9 sodium tripolyphosphate aqueous solution dropwise at a volume ratio of 5:1 (chitosan degradation solution to sodium tripolyphosphate aqueous solution), stirring continuously for 0.2 h. Finally, dilute with ultrapure water to a 10-fold concentration to obtain the nano-chitosan leaf surface regulator, and store it in a refrigerator at 4°C.

[0065] Step 3: Before planting or transplanting rice seedlings, fertilize, till, and flood the arsenic-contaminated paddy field soil. The base fertilizer includes urea, KH2PO4, and K2SO4 in a mass ratio of N:P2O5:K2O = 0.15:0.15:0.10 (g·kg). -1 );

[0066] Step 4: Plant rice or transplant dry rice in the arsenic-contaminated paddy soil obtained in Step 3. When the rice reaches the grain-filling stage, spray the leaves with the nano-chitosan leaf regulator prepared above 4 times, 0.3 liters / square meter each time, with an interval of 5 days between each time. Allow the paddy soil to dry naturally during the waxy ripening stage of the rice and thereafter until the rice is harvested.

[0067] The management methods for fertilization, tilling, flooding, and rice growth (including the grain-filling stage, the waxy ripening stage, and beyond) are the same as those for conventional rice management.

[0068] Comparative Example 1

[0069] Step 1: Dissolve chitosan in 3% acetic acid solution at a ratio of 1g:30mL (m:v) and place in a water bath at 40-50℃. Stir at 200-250 rpm for 1-2 hours until completely dissolved. Finally, dilute with ultrapure water to 20 times to obtain chitosan leaf surface regulator and store in a refrigerator at 4℃.

[0070] Step 3: Before planting or transplanting rice seedlings, fertilize, till, and flood the arsenic-contaminated paddy field soil. The base fertilizer includes urea, KH2PO4, and K2SO4 in a mass ratio of N:P2O5:K2O = 0.15:0.15:0.10 (g·kg). -1 );

[0071] Step 4: Plant rice or transplant rice seedlings in the arsenic-contaminated paddy soil obtained in Step 3. When the rice reaches the grain-filling stage, spray the leaves twice with the nano-chitosan leaf regulator prepared above, 0.35 liters / square meter each time, with an interval of 4 days between the two applications. Allow the paddy soil to dry naturally during and after the rice wax-ripe stage until the rice is harvested.

[0072] The fertilization, tillage, flooding, and management methods during the rice growth process (including the grain-filling stage, the waxy ripening stage, and beyond) are the same as in Example 3.

[0073] Blank group experiment

[0074] The difference between this blank group experiment and Example 1 is that chitosan leaf regulator was not sprayed, but an equal amount of deionized water was sprayed on the rice leaves instead of chitosan leaf regulator. This is represented by CK.

[0075] The method for measuring the arsenic content in rice, rice husks, and leaves of the examples, comparative examples, and control groups is as follows:

[0076] Fresh rice plants were collected, washed, and separated into different parts. The rice leaves, husks, and grains were placed in a drying oven and blanched at 105℃ for 30 minutes. They were then dried at 70℃ until the weight stabilized and then chopped. Finally, the different parts of the rice plants were digested, and the arsenic content in the different parts of the rice plants was determined by ICP-MS.

[0077] The test results for arsenic content in rice are shown in the attached figure.

[0078] As shown in Examples 1-2 and the blank group, spraying rice leaves with nano-sized chitosan leaf regulator can regulate and reduce the absorption and translocation of arsenic in rice grains during the grain-filling stage, increase the arsenic content in rice husks and leaves, and reduce the translocation of arsenic from soil to grains, thus significantly reducing the arsenic content in different types of rice.

[0079] As can be seen from Example 3 and Comparative Example 1, compared with chitosan alone, the nano-sized chitosan leaf regulator modified by nanosol in this invention can regulate and reduce the absorption and translocation of arsenic in rice grains during the grain-filling period, increase the arsenic content in rice husks and leaves, and has a more significant effect in reducing the translocation of arsenic from the soil to the grains.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. The application of a foliar regulator in reducing arsenic content in rice, characterized in that, The process includes the following steps: First, fertilize, till, and flood the arsenic-contaminated paddy field soil; then plant or transplant rice seedlings; when the rice reaches the grain-filling stage, apply a foliar growth regulator 1-4 times, 0.3-0.4 liters / square meter each time, with an interval of 3-5 days between each application; allow the paddy field soil to dry naturally during and after the rice's waxy ripening stage until the rice is harvested. The preparation method of the foliar regulator includes the following steps: (1) Hydrogen peroxide solution was added to chitosan acetic acid solution to carry out hydrogenolysis reaction to obtain degraded chitosan solution; (2) Add sodium tripolyphosphate solution to the degraded chitosan solution to carry out sol-gel reaction, and then add water to dilute to obtain the leaf surface regulator.

2. The application of the foliar regulator as described in claim 1 in reducing arsenic content in rice, characterized in that, The volume ratio of the hydrogen peroxide solution to the chitosan acetic acid solution is 0.2-1.

3. The application of the foliar regulator as described in claim 1 in reducing arsenic content in rice, characterized in that, The volume ratio of the degraded chitosan solution to the sodium tripolyphosphate solution is 5:(1-2).

4. The application of the foliar regulator as described in claim 1 in reducing arsenic content in rice, characterized in that, The chitosan-acetic acid solution is composed of chitosan and acetic acid solution. The mass ratio of chitosan to acetic acid solution in the chitosan-acetic acid solution is 1 g:(25-30 mL). The mass concentration of acetic acid in the acetic acid solution is 2-4%. The mass concentration of hydrogen peroxide solution is 4-6%.

5. The application of the foliar regulator as described in claim 1 in reducing arsenic content in rice, characterized in that, The hydrogenolysis reaction is carried out at a temperature of 55–65°C for 3–6 hours.

6. The application of the foliar regulator as described in claim 1 in reducing arsenic content in rice, characterized in that, The sol-gelation reaction takes 0.2-1 h and is carried out at a temperature of 30-40 °C.

7. The application of the foliar regulator as described in claim 1 in reducing arsenic content in rice, characterized in that, The stirring rate for the hydrogenolysis reaction is 300–350 rpm; the pH value of the sodium tripolyphosphate solution is 7–9; and the dilution factor is 10–30 times.

8. The application of the foliar regulator as described in claim 1 in reducing arsenic content in rice, characterized in that, In fertilization, the base fertilizer includes urea, KH2PO4 and K2SO4.

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