Method for improving soil properties of dry farmland by using low-concentration hypochlorous acid

Abstract

The invention discloses a method for improving the property of dry farmland soil by using low-concentration hypochlorous acid, which comprises the following steps: after the soil is turned over to be fluffy, uniformly spraying persulfate solutions with different concentrations on the surface, and controlling the water-soil ratio to be 1: 2; the invention further discloses application of the method in the process of improving basic physicochemical properties of farmland soil. The pypocholoride with different concentrations is added into the dry land soil, so that the quality of the dry land soil is improved. By applying a low dosage of sodium hypochlorite oxidizing agent to the long-term cultivated dry land soil, the soil quality can be improved, for example, the content of soil dissolved organic carbon (DOC) and bio-available iron, manganese, zinc and the like is increased, the number of harmful fungi is reduced, the structure of a soil microbial community is improved, the recovery speed of the soil microbial community is increased, and the soil productivity is rapidly improved.

Description

Technical Field

[0001] The invention relates to the technical field of improving farmland soil properties and soil fertility, and in particular to a method for improving farmland dryland soil properties by using low-concentration hypochlorous acid. Background Art

[0002] Soil is the material basis for human survival and development. In today's world where the contradiction between "people and land" is becoming increasingly acute, soil quality issues have become a hot topic of concern. Analyzing and evaluating soil quality and predicting the direction and trend of soil quality evolution are the basis for studying the mechanism of soil quality changes and regulating soil conservation capabilities. Soil quality mainly includes three aspects: soil fertility quality, environmental quality, and health quality. Factors affecting soil quality include natural factors and human factors. Among them, soil quality degradation (such as soil acidification, low fertility, etc.) caused by unreasonable human activities (such as agronomic measures such as greenhouse facilities) is much more serious than the impact of natural factors.

[0003] Many studies have shown that due to the long-term lack of irrigation, rainwater leaching and high evaporation, the aeration conditions and water and fertilizer management measures of dryland farmland are different from those of paddy field soil (such as rice field soil), resulting in many problems such as secondary salinization, soil acidification, nutrient imbalance, and weak fertility. In addition, dryland soil has been subjected to improper production measures such as intensive production, continuous planting, and excessive fertilization, which has caused soil salinization and soil-borne diseases to worsen, reducing crop quality and yield, reducing farmers' income, and seriously affecting the promotion and planting of dryland crops (such as corn, sorghum, etc.). Therefore, in order to promote the further development of dryland soil farming agriculture, it is particularly important to study the relevant solutions to the maintenance of dryland soil fertility and continuous cropping obstacles. After long-term efforts by scientists, although a variety of methods have been developed to eliminate or alleviate the negative plant-soil feedback effect (PSF) to prevent and control crop soil-borne diseases, the problem of frequent crop soil-borne diseases in intensive agricultural production has not been fundamentally solved. The plant-soil feedback effect and farmland production characteristics determine the unsustainability of farmland soil productivity. Therefore, it is necessary to develop green and efficient soil control measures to keep the soil fertility fresh.

[0004] Oxidants (such as hypochlorous acid, etc.) are often used in the remediation of organic pollution in water bodies, soil and other places because they have strong oxidizing properties and can be activated under certain conditions to produce strong oxidizing free radicals. The substance that has a disinfecting effect in chlorine-containing disinfectants is hypochlorous acid generated after the disinfectant is dissolved in water. It has strong oxidizing properties. Strong oxidants can destroy soil aggregates, and can also react with lipid double bonds in the cell walls of microorganisms, enter the interior of microorganisms, act on proteins and lipopolysaccharides, change the permeability of cells, and cause cell lysis and death. Advanced oxidation treatment to remediate contaminated soil is to inject oxidants into the soil, remove organic pollutants in the soil or groundwater through redox reactions to produce free radicals, and degrade them into non-toxic or low-toxic substances. While high-concentration oxidants repair organic pollution in sites, they can also promote the release of soil dissolved organic matter and the diffusion of aggregates. Therefore, the application of low-concentration oxidants to farmland soil may significantly promote the increase of soil dissolved organic matter (including bioavailable parts), key nutrient content (nitrogen, phosphorus, potassium, etc.) and the improvement of soil structure (aggregate composition, porosity). Moreover, the treatment effects of different oxidants on soil are affected by many factors, including the type and dosage of the oxidant, catalyst, pH, treatment time, and the concentration and composition of pollutants in the soil. Therefore, the treatment effects of oxidants under different conditions are not the same, and the impacts on the physical and chemical properties of the soil and the biological community are also different.

[0005] Therefore, there are no reports on the research on improving farmland soil properties with low-concentration oxidants. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for improving the properties of dry farmland soil by using low-concentration hypochlorous acid, which can solve the problems of low fertility and poor fertility of farmland soil.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide a method for improving the properties of dry farmland soil using low-concentration hypochlorous acid, after the soil is plowed and fluffed, hypochlorous acid solutions of different concentrations are evenly sprayed on the surface to control the water-soil ratio to 1:2.

[0008] In a preferred embodiment of the present invention, the hypochlorous acid solution is a room temperature aqueous solution, and the concentration is selected to be 1‰ to 5‰.

[0009] In a preferred embodiment of the present invention, liquid oxidant hypochlorous acid is sprayed into the soil and then left to stand for 3-5 days.

[0010] In a preferred embodiment of the present invention, the improvement effect is mainly within 10 cm of the soil surface.

[0011] Furthermore, the soil is farmland dryland soil, such as farmland soil where corn is grown for a long time.

[0012] In order to solve the above technical problems, another technical solution adopted by the present invention is: to provide an application of the method for improving the properties of dry farmland soil using low-concentration hypochlorous acid as described above in the process of improving the basic physical and chemical properties of farmland soil.

[0013] Adding 1‰ and 5‰ hypochlorous acid to farmland soil will change the soil aggregate structure and oxidize and decompose organic matter after entering the soil, thereby causing changes in the microbial community in the soil and promoting the accumulation of bioavailable soil nutrients such as Fe, Mn, and Zn.

[0014] Specifically, the improvement effects include increasing the content of available phosphorus, ammonium nitrogen, available Fe, Mn, Zn and DOC in the soil, increasing the content of beneficial microorganisms, and reducing pathogenic bacteria.

[0015] The beneficial effects of the present invention are:

[0016] (1) The present invention adds an oxidant, persulfate, to farmland soil to change the soil's physical and chemical properties and microbial community distribution, thereby promoting the accumulation of bioavailable active components such as Fe, Mn, and Zn, and having a good improvement effect on the soil's physical and chemical properties;

[0017] (2) The oxidant of the present invention uses low-concentration hypochlorous acid, which has little secondary pollution to farmland soil on the basis of beneficial effects;

[0018] (3) Adding different concentrations of hypochlorous acid can change the physical and chemical properties of the soil and have a significant impact on the microbial structure and content distribution of the soil, beneficial bacteria, and harmful bacteria;

[0019] (4) The present invention is simple to operate, economically feasible, environmentally friendly, and suitable for improving farmland soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the result graph of the effect of pure water control group and 1‰ and 5‰ hypochlorous acid treatment groups on soil pH;

[0021] Figure 2 This is a graph showing the changes in the content of iron, manganese and zinc in the soil between the pure water control group and the groups treated with 1‰ and 5‰ hypochlorous acid.

[0022] Figure 3 This is the result graph of the effects of the pure water control group and the 1‰ and 5‰ hypochlorous acid treatment groups on the activities of different enzymes in the soil;

[0023] Figure 4 This is a graph showing the changes in the abundance of different types of microorganisms in the soil between the pure water control group and the groups treated with 1‰ and 5‰ hypochlorous acid. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0025] The present invention collects farmland soil samples from Nanjing Liuhe where corn has been planted for a long time, explores the farmland soil after being treated with hypochlorous acid at different concentrations, measures the soil's physical and chemical properties, key nutrient content, DOC, microbial community structure, etc., evaluates the soil quality and pathogenic bacteria, and explores the impact of oxidants on different soil indicators, thereby evaluating the beneficial improvement effects of different low-concentration oxidant treatment measures on the soil. On the one hand, the relevant research results can accumulate practical experience in the restoration and management of nutrient-poor soils in medium and low-yield fields; on the other hand, they can directly guide local agricultural production and serve local economic development. Embodiments of the present invention include:

[0026] Embodiment 1:

[0027] A 250mL round-bottom beaker was used as the reaction container. 220g of soil was weighed in each beaker. Hypochlorous acid was added to the treatment group at a concentration of 1‰ and 5‰. Persulfate was dissolved in 110mL ultrapure water, and the water-soil ratio was controlled to be 1:2. After the solution completely permeated the soil, it was left to stand for 3-5 days. At the same time, a control treatment of adding only pure water was set. After standing, the pH value was measured at 1, 5, 10, and 15 days, and the soil after standing was divided into three layers, upper, middle, and lower, dried, and sieved through a 10-mesh sieve to measure the physical and chemical properties such as available phosphorus, available potassium, ammonium nitrogen, and nitrate nitrogen.

[0028] The results showed that the pH of the soil was between 5.5 and 6.5, showing a weak acidity. After the addition of hypochlorous acid, the pH value dropped and stabilized between 5.6 and 5.8. The contents of available potassium, available phosphorus, ammonium nitrogen, and nitrate nitrogen in the 5‰ hypochlorous acid treatment group were higher than those in the 1‰ hypochlorous acid treatment group.

[0029] Increasing the application of nitrogen fertilizer has a significant effect on improving corn yield, individual plant growth and development, canopy light distribution characteristics and population structure. When the soil pH is 6-8, the effect of nitrogen application on improving cotton yield and water use efficiency is most obvious; after the bean harvest, the C / N ratio of plant residues is low, and nutrients are easily decomposed and released, which can improve the soil supply of N, P, and K, and is beneficial to the maintenance of soil fertility and nutrient recycling.

[0030] Table 1 Changes in soil ammonium nitrogen, nitrate nitrogen, available phosphorus and available potassium contents after treatment with different oxidants

[0031]

[0032] Embodiment 2:

[0033] A 250mL round-bottom beaker was used as the reaction container. 220g of soil was weighed in each beaker. Hypochlorous acid was added to the treatment group at a concentration of 1‰ and 5‰. Persulfate was dissolved in 110mL ultrapure water, and the water-soil ratio was controlled to be 1:2. After the solution completely soaked the soil, it was left to stand for 3-5 days. At the same time, a control treatment of adding only pure water was set. After standing, the soil was divided into three layers, upper, middle and lower, dried, and passed through a 10-mesh sieve to determine the content of iron, manganese and zinc. The results are as follows Figure 2 As shown in a, it can be seen from the upper middle layer that the content of bioavailable Fe increased after the addition of oxidants compared with the control treatment; it can be seen from the lower layer that the content of bioavailable Fe in the 1‰ hypochlorous acid treatment group was the highest.

[0034] The results are as follows Figure 2 As shown in (b), from the results of the upper soil layer, it can be seen that after the addition of the oxidant hypochlorous acid, the content of bioavailable Mn has changed significantly, among which the 1‰ hypochlorous acid treatment group has the highest content of bioavailable Mn; the data of the middle and lower soil layers show that the content of bioavailable Mn increases after the addition of hypochlorous acid.

[0035] The results are as follows Figure 2 As shown in Figure c, from the results of the upper soil, it can be seen that the content of bioavailable Zn did not change significantly after the addition of hypochlorous acid; and from the results of the middle soil, compared with the control treatment, the content of bioavailable Zn had significant differences after the addition of oxidants, among which the Zn content in the 1‰ hypochlorous acid treatment group was the lowest; from the data results of the lower soil, it can be seen that the content of bioavailable Zn decreased after the addition of oxidants.

[0036] Applying zinc and iron fertilizers can increase the chlorophyll content and photosynthetic rate of leaves, and iron fertilizer can promote the good growth of soybeans; it also has a promoting effect on rice and wheat; the biological effectiveness of manganese to plants is affected by soil conditions. The manganese effectiveness in soils with high pH or high organic matter, low water content or high soil porosity is lower. Increasing the application of manganese fertilizers has a promoting effect on wheat, alfalfa, soybeans and corn.

[0037] Embodiment 3:

[0038] A 250mL round-bottom beaker was used as the reaction container. 220g of soil was weighed in each beaker. Persulfate was added to the treatment group at concentrations of 1‰ and 5‰. The persulfate was dissolved in 110mL ultrapure water, and the water-soil ratio was controlled to be 1:2. After the solution completely permeated the soil, it was left to stand for 3-5 days. At the same time, a control treatment of adding only pure water was set up. After the standing was completed, the soil was divided into three layers, upper, middle and lower, and the enzyme activity was measured. The enzyme activity indicators measured mainly include: catalase, acid phosphatase, sucrase, and urease. The results are as follows Figure 3As shown, soil enzyme activity is related to factors such as the number of soil microorganisms, organic matter content, and pH, and is also an important indicator for evaluating soil fertility and health. After adding hypochlorous acid, various enzyme activity indicators increased, indicating that the addition of oxidants has a certain stimulating effect on soil enzyme activity.

[0039] Embodiment 4:

[0040] The field soil was divided into CK (without any oxidant), 100ppm and 1500ppm hypochlorous acid treated dryland soil samples, and 2g of wet soil was placed in a -80℃ refrigerator for microbial testing. Figure 4 , it was found that the addition of hypochlorous acid increased the abundance of beneficial bacteria such as Chaetomium and Trichoderma;

[0041] Chaetomium globosum can effectively improve the stress resistance of plants and has a very good control effect on a variety of plant diseases. It can inhibit the growth of many common plant pathogens such as Fusarium and Phytophthora, thereby controlling plant diseases to a certain extent. Figure 4 a It can be seen that after adding the oxidant, the number of Chaetomium also increased. The best effect was achieved when 100ppm hypochlorous acid was used. Figure 4 b Trichoderma has a strong colonization ability in the soil, which can effectively improve the physical and chemical environment of the soil, promote the establishment and maintenance of beneficial soil microbial communities, increase crop resistance, and thus promote crop growth and increase crop yields. Trichoderma can also effectively enhance the vitality of corn roots and increase soil aggregates. After adding oxidants, it was found that the number of Trichoderma increased significantly compared to CK.

[0042] However, it has a reducing effect on pathogenic bacteria such as Phytophthora and Alternaria; crop blight is one of the major diseases in global agricultural production, posing a serious threat to global food and ecological security, and causing economic losses of up to hundreds of billions of yuan to vegetable crops such as potatoes and tomatoes and cash crops such as soybeans in my country every year. As can be seen from Figure 4c, as the concentration of oxidants increases, the number of Phytophthora decreases, indicating that oxidants have a certain killing effect on it. Alternaria is a common strong parasitic pathogenic fungus in the growth process of white clover, which has a huge impact on cereal crops such as wheat, rice and sorghum, oil crops such as rapeseed and soybeans, vegetables and fruits such as tomatoes, potatoes, eggplants, peppers, apples, pears, ornamental flowers such as aloe vera and chrysanthemums, and cash crops such as cotton and tobacco. Figure 4 d shows that after adding the oxidant, the abundance of Alternaria alternata decreased significantly. As the concentration of the oxidant increased, its abundance decreased more. This shows that adding hypochlorous acid to dryland soil can effectively kill harmful microorganisms.

[0043] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for improving the properties of dry farmland soil using low concentration hypochlorous acid, characterized in that: After the soil is plowed and fluffed, spray hypochlorous acid solutions of different concentrations evenly on the surface to control the water-soil ratio to 1:

2.

2. The method for improving the properties of dry farmland soil using low concentration hypochlorous acid according to claim 1, characterized in that: The hypochlorous acid solution is a room temperature aqueous solution, and the concentration is selected to be 1‰ to 5‰.

3. The method for improving the properties of dry farmland soil using low concentration hypochlorous acid according to claim 1, characterized in that: Spray the soil with liquid oxidant hypochlorous acid and leave it there for 3-5 days.

4. The method for improving the properties of dry farmland soil using low concentration hypochlorous acid according to claim 1, characterized in that: The improvement effect is mainly within the 10 cm range of the soil surface.

5. The method for improving the properties of dry farmland soil using low concentration hypochlorous acid according to any one of claims 1 to 4, characterized in that: The soil is farmland dryland soil.

6. Use of the method for improving the properties of dry farmland soil using low-concentration hypochlorous acid as described in any one of claims 1 to 5 in the process of improving the basic physical and chemical properties of farmland soil.

7. The use according to claim 6, characterized in that: The improvement effects include increasing the content of available phosphorus, ammonium nitrogen, available Fe, Mn, Zn and DOC in the soil, increasing the content of beneficial microorganisms, and reducing pathogenic bacteria.

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