Humic acid-based water-soluble fertilizer for rapid improvement of Baijiang soil

Abstract

The invention discloses a humic acid-based water-soluble fertilizer for rapid improvement of Baijiang soil. The method comprises the following steps: crushing a raw material containing humic acid, removing impurities to obtain a pretreated raw material, mixing the pretreated raw material with water to obtain a mixed solution, adding alkali containing sodium, heating, stirring for reaction, and performing solid-liquid separation after reaction to obtain a sodium humate solution; adding a silane coupling agent into the solution containing the humic acid, heating and stirring, respectively dropwise adding tannic acid and lecithin under the condition of heat preservation, and continuously reacting after dropwise adding to obtain the humic acid solution. The humic acid solution disclosed by the invention can realize transverse and longitudinal rapid diffusion in the white slurry soil along with water, and can effectively penetrate through a soil plough layer to directly act on a white slurry area of a bottom layer. The humic acid-based water-soluble fertilizer prepared from the humic acid solution can provide sufficient nutrients for plant growth while realizing targeted remediation of white pulpified soil, and provides powerful support for sustainable development of agricultural production.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, and in particular to a humic acid-based water-soluble fertilizer for rapid improvement of albic soil. Background Art

[0002] Albic soil is one of the most widely distributed soil types in Northeast my country. It is a typical low-yield barrier soil. Its soil profile can be divided into four categories, namely humus layer, albic soil layer, lake base layer and parent material layer (Dai Lin, 2017). The albic soil layer with strong albic soil characteristics is characterized by a typical silt and flaky structure. Due to its own soil compaction, poor permeability, drought and flood resistance, low soil organic carbon content, poor crop yield and quality, the average yield reduction is 20% (Yang Song et al., 2020; Zhang Xu, 2021), which seriously affects the sustainable development of agriculture in Northeast China. Soil is a non-renewable and precious resource. In order to meet the growing population's demand for food yield and quality and achieve sustainable development of agriculture, it is necessary to repair and improve the barrier albic soil and improve soil quality (Sun Qiang, 2020).

[0003] The main difficulties faced in repairing and improving albic soil are: (1) hard albic layer. The most notable feature of albic soil is that it contains a hard albic layer. This layer of soil is heavy, airtight and impermeable, which hinders the penetration of crop roots and the absorption of deep nutrients. Therefore, how to effectively transform this albic layer is the key to improving albic soil; (2) low nutrient content. The tillage layer of albic soil is shallow, the nutrient content is low, and it contains more toxic substances, such as excessive aluminum and manganese, which will affect the normal growth of crops. Therefore, improving soil Improving fertility and increasing nutrient content are important tasks in improving albic soil; (3) Albic soil has poor drought and waterlogging resistance. Its water retention and drainage are poor, which makes the soil prone to drought or waterlogging, thus affecting crop growth. Therefore, in the process of improvement, it is necessary to enhance the soil's water storage and moisture retention function and improve the soil's physical properties; (4) The improvement cycle is long. Soil formation is a long process, and improving soil also takes a certain amount of time. For barrier soils such as albic soil, its improvement is more difficult and requires long-term efforts to achieve significant results.

[0004] At present, the main measures for improving albic soil are: returning straw to the field, improving organic fertilizer and improving biochar. However, after straw is applied to the soil, it takes a long time to degrade and it is difficult to quickly provide nutrients; organic fertilizer itself has a low fertilizer efficiency and needs to be applied at the same time as chemical fertilizer to achieve better results; biochar is a more suitable improvement material, but its preparation cost is high and it is difficult to recover the cost in actual application. Therefore, it is still necessary to develop measures to quickly improve albic soil. Summary of the invention

[0005] In view of the above-mentioned prior art, the purpose of the present invention is to provide a humic acid-based water-soluble fertilizer for rapid improvement of white soil. The present invention first prepares a humic acid solution, which can achieve rapid lateral and longitudinal diffusion in white soil with water, can effectively penetrate the soil plow layer and directly act on the white pulp area of ​​the bottom layer, and achieves targeted repair of white pulp soil. The present invention also uses the humic acid solution to prepare a humic acid-based water-soluble fertilizer for rapid improvement of white soil, which achieves targeted repair of white pulp soil while providing sufficient nutrients for plant growth. Using humic acid-based water-soluble fertilizer to improve white soil not only simplifies and saves the investment of large-scale machinery, but also can solve the problem of soil white pulp from the source, providing strong support for the sustainable development of agricultural production.

[0006] To achieve the above object, the present invention adopts the following technical solution: In a first aspect of the present invention, a humic acid solution is provided, wherein the preparation method of the humic acid solution is: A silane coupling agent is added to the solution containing humic acid, heated and stirred, and then tannic acid and lecithin are added dropwise respectively under heat preservation, and after the addition is completed, the reaction is continued to obtain a humic acid solution.

[0007] Preferably, the solution containing humic acid is a sodium humate solution, and its preparation method is: The raw material containing humic acid is crushed and impurities are removed to obtain a pretreated raw material, the pretreated raw material is mixed with water to obtain a mixed solution, an alkali containing sodium is added, heated and stirred for reaction, and solid-liquid separation is performed after the reaction to obtain a sodium humate solution.

[0008] Preferably, the mass ratio of the pretreated raw material to water is 1:1.4; the sodium-containing alkali is NaOH solution or Na2CO3 solution, and the mass concentration of the NaOH solution or Na2CO3 solution is greater than 95%; the mass ratio of the sodium-containing alkali to the mixed solution is 1:5.

[0009] Preferably, the raw material containing humic acid is weathered coal or lignite; the heating temperature is 30-35° C.; and the stirring reaction time is 30-40 min.

[0010] Preferably, the heating and stirring temperature is 50-70° C., and the time is 10-30 min; and the continued reaction time is 10-30 min.

[0011] Preferably, the mass ratio of the solution containing humic acid, the silane coupling agent, tannic acid and lecithin is 100:5~10:2~4:2~4.

[0012] Preferably, the silane coupling agent is KH560; and the dropping speed is 1-3 mL / min.

[0013] The second aspect of the present invention provides the use of a humic acid solution in rapidly penetrating albic soil or preparing a humic acid-based water-soluble fertilizer.

[0014] A third aspect of the present invention provides a humic acid-based water-soluble fertilizer for rapid improvement of albic soil, wherein the humic acid-based water-soluble fertilizer contains the humic acid solution.

[0015] Preferably, the humic acid-based water-soluble fertilizer further contains the following raw materials: 145~170g / L urea, 115~155g / L monoammonium phosphate, 95~115g / L potassium chloride, 0.5~1.5 g / L zinc sulfate, 0.5~1.5 g / L ferrous sulfate, 0.5~1.5 g / L manganese sulfate, 0.5~1.5 g / L copper sulfate, 0.5~2g / L rare earth elements, 0.5~1.5 g / L defoamer, 1.0~6.5 g / L thickener.

[0016] Beneficial effects of the present invention: (1) The present invention uses tannic acid and lecithin to increase the rapid lateral and longitudinal diffusion of sodium humate solution in soil, and couples tannic acid and lecithin with the sodium humate solution through a silane coupling agent, thereby further increasing the penetration rate of the sodium humate solution in white soil.

[0017] (2) The present invention uses humic acid solution to prepare humic acid-based water-soluble fertilizer for rapid improvement of albic soil, achieving targeted repair of albic soil and providing sufficient nutrients for plant growth. This method of improving albic soil not only simplifies and saves the investment of large-scale machinery, but also can solve the problem of soil albic soil from the source, providing strong support for the sustainable development of agricultural production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : Schematic diagram of one-dimensional vertical infiltration test; Figure 2 : Schematic diagram of one-dimensional horizontal imbibition test; Figure 3 : The influence of each group of humic acid solutions on the vertical wetting front; Figure 4 : The influence of each group of humic acid solutions on the horizontal wetting front; Figure 5 : Comparison of soil porosity of each group of humic acid water-soluble fertilizer; Figure 6 : Comparison of soil bulk density of each group of humic acid water-soluble fertilizer; Figure 7 : Comparison of soil organic matter in each group of humic acid water-soluble fertilizer. DETAILED DESCRIPTION

[0019] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0020] As introduced in the background technology section, the main difficulties faced in repairing and improving white soil are: hard white pulp layer. The most notable feature of white soil is that it contains a hard white pulp layer. This layer of soil is heavy, airtight and impermeable, which hinders the penetration of crop roots and the absorption of deep nutrients. Therefore, the focus of improving white soil is that the modifier can achieve rapid lateral and vertical diffusion in the white soil. However, the current improvement measures for white soil mainly include: straw return improvement, organic fertilizer improvement and biochar improvement, etc., none of which can achieve rapid penetration or rapid diffusion.

[0021] Based on this, the purpose of the present invention is to provide a humic acid-based water-soluble fertilizer for rapid improvement of white pulp soil. The present invention first prepares a humic acid solution, and uses sodium humate solution to couple tannic acid and lecithin to obtain a humic acid solution that can quickly penetrate and diffuse. Although tannic acid and lecithin both have the function of surfactants, they can reduce the surface tension of the liquid and improve the wettability and emulsification stability of the liquid; but not all surfactants that can reduce the surface tension of the liquid and improve the wettability and emulsification stability of the liquid are suitable for the sodium humate solution of the present application. After many experiments and studies, the wetting agents and emulsifiers commonly used in water-soluble fertilizers were abandoned, and it was found that tannic acid and lecithin were used together and coupled with sodium humate solution to obtain a humic acid solution with the fastest penetration and diffusion speed. The present invention also mixes humic acid solution with raw materials such as urea to obtain a humic acid-based water-soluble fertilizer, which not only realizes the targeted repair of white pulp soil but also provides sufficient nutrients for plant growth, thereby realizing the rapid improvement of white pulp soil.

[0022] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0023] Note: Tannic acid (CAS: 1401-55-4) in the present invention was purchased from Xi'an Zebang Biotechnology Co., Ltd. Lecithin (powdered soybean lecithin) was purchased from Guangzhou Tianbao Biotechnology Co., Ltd.; The defoamer was a silicone polyether defoamer purchased from Guangdong Shanmei Environmental Technology Co., Ltd. Thickener (C-152) was purchased from Guangdong Zhongke Hongtai New Materials Co., Ltd.

[0024] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0025] Example 1: Preparation of humic acid solution (1) Take lignite as raw material (humic acid content ≥ 30%), crush the raw material to less than 2 mm by a pulverizer, and then remove impurities by air separation equipment (such as a cyclone dust collector) to improve the purity of the raw material to obtain pretreated lignite. Add the pretreated lignite and water in a mass ratio of 1:1.4 into a reactor to obtain a mixed solution, add NaOH solution (mass concentration > 95%) to the mixed solution in a mass ratio of 1:5, heat to 35°C in the reactor, and stir for 30 minutes to fully dissolve the humic acid in the alkali solution. Use a rotary solid-liquid separator to separate the solid-liquid of the reaction mixture to obtain a sodium humate solution. The temperature is lowered to room temperature for standby use.

[0026] (2) Add 6 g of KH560 to 100 g of sodium humate solution, heat and stir at 60 °C for 20 min, then add 3 g of tannic acid and 3 g of lecithin dropwise at a rate of 2 mL / min while keeping warm. After the addition is complete, continue the reaction for 20 min to obtain a humic acid solution.

[0027] Example 2: Preparation of humic acid-based water-soluble fertilizer The following substances were added to the humic acid solution prepared in Example 1: 155 g / L urea, 135 g / L monoammonium phosphate, 105 g / L potassium chloride, 1.0 g / L zinc sulfate, 1.0 g / L ferrous sulfate, 1.0 g / L manganese sulfate, 1.0 g / L copper sulfate, 1.25 g / L rare earth elements, 1.0 g / L defoamer, and 3.5 g / L thickener, and the mixture was stirred and mixed to obtain a humic acid water-soluble fertilizer product.

[0028] Comparative Example 1 Take lignite as raw material (humic acid content ≥ 30%), crush the raw material to less than 2mm by a pulverizer, and then remove impurities by air separation equipment (such as cyclone dust collector) to improve the purity of the raw material to obtain pretreated lignite. Add the pretreated lignite and water into the reactor at a mass ratio of 1:1.4 to obtain a mixed solution, add NaOH with a purity of more than 95% to the mixed solution at a mass ratio of 1:5, heat to 35°C in the reactor, and stir for 30 minutes to fully dissolve the humic acid in the alkali solution. Use a rotary solid-liquid separator to separate the solid and liquid of the reaction mixture, and obtain a sodium humate solution after the temperature is reduced to room temperature.

[0029] Comparative Example 2 The difference from Example 1 is that KH560 is not added, and a humic acid solution is finally obtained.

[0030] Comparative Example 3 The difference from Example 1 is that lecithin is not added, and a humic acid solution is finally obtained.

[0031] Comparative Example 4 The difference from Example 1 is that no tannic acid is added, and a humic acid solution is finally obtained.

[0032] Comparative Example 5 The difference from Example 1 is that tannic acid and lecithin are replaced with an equal amount of OPC-8 (purchased from Shandong Shoucheng Chemical Co., Ltd.), and a humic acid solution is finally obtained.

[0033] Comparative Example 6 The difference from Example 2 is that the humic acid solution prepared in Comparative Example 1 is used instead of the humic acid water-soluble fertilizer product prepared in Example 1.

[0034] Comparative Example 7 The difference from Example 2 is that the humic acid solution prepared in Comparative Example 5 is used instead of the humic acid water-soluble fertilizer product prepared in Example 1.

[0035] Test Example 1: Horizontal and vertical diffusion test In this test, meadow white pulp soil (profile configuration is Ah-E-Bt-Cg) from Shuguang Farm, Huanan County, Jiamusi City was selected, and the white pulp layer soil 20-40cm below the surface was drilled, naturally air-dried, sieved, and then ground with a mortar to 100-150 mesh for use. Referring to the measured bulk density of the local soil and the actual volume of the experimental device, the soil bulk density was set to 1.67g / cm³. The test was divided into 6 groups: Example 1 group, Comparative Examples 1 to 5 groups, and the humic acid solution of each group was irrigated for vertical and horizontal penetration tests.

[0036] 1. Use a vertical one-dimensional water accumulation constant head infiltration system such as Figure 1 As shown in the figure, the effect of humic acid solution on the vertical permeability of white soil was investigated.

[0037] The ground white slurry soil was filled into the plexiglass column to obtain the white slurry soil column. The height of the soil column was 40 cm. Filter paper was laid on the top and bottom to ensure the air permeability of the device. The white slurry soil was filled in layers and the layers were roughened to prevent stratification. Each group of humic acid solutions was added to a Martens flask of the same specifications as the plexiglass column, and the soil column was watered. During the watering process, the water head of the humic acid solution was kept stable at 3-4 cm. In order to ensure the accuracy of the experimental data, the data was recorded by intensive sampling in the early stage and then extending the time interval between sampling points. A humidity sensor was used to regularly record the position of the wetting front. At the beginning, due to the fast infiltration rate, the measurement was performed once every minute for the first 5 minutes, once every 5 minutes within 5-30 minutes, and once every 10 minutes after 30 minutes. The movement distance of the wetting front in the same time interval was calculated to obtain the influence of the humic acid solution on the vertical wetting front. When the migration distance of the wetting front reached 40 cm, the experiment was stopped to obtain the influence of the humic acid solution on the vertical wetting front (see Figure 3After draining the accumulated water (humic acid solution) quickly, soil samples were collected at different depths every 5 cm using an aluminum box, and the moisture content of each section of soil, soil cumulative infiltration and other related data were determined using the drying method.

[0038] 2. One-dimensional horizontal infiltration system such as Figure 2 As shown in the figure, it consists of a water supply device and a soil column (the soil column is filled with a plexiglass column). The water supply device uses a Martens flask of the same specifications as the plexiglass column of the soil column, with an inner diameter and a total height of 10 cm and 40 cm respectively, to ensure continuous water supply (humic acid solution) throughout the experiment. The soil column is made by filling ground white slurry soil into a cylindrical transparent container. A 3 cm water storage chamber is set at the front end of the soil column, equipped with vents, drains and water inlet pipes for water storage, drainage and water supply connection. The main body of the soil column is a 40 cm long open plexiglass column, with soil holes set every 5 cm on the upper part for measuring soil moisture content after the test. The water storage chamber and the soil column are connected by small holes to ensure uniform distribution of accumulated water and eliminate the influence of gravity and capillary action. A humidity sensor is used to regularly record the position of the wetting front. At the beginning, due to the rapid infiltration rate, the water is measured once a minute in the first 5 minutes, once every 5 minutes within 5-30 minutes, and once every 10 minutes after 30 minutes. The influence of humic acid solution on the horizontal wetting front was obtained by calculating the moving distance of the wetting front in the same time interval (see Figure 4 ). The drying method is used to determine the moisture content of each section of soil, soil cumulative infiltration and other related data.

[0039] 3. According to the FPhilip model and Brooks-Corey model, the relevant data such as moisture content and soil cumulative infiltration obtained from horizontal infiltration and vertical infiltration were fitted to calculate the water absorption rate and soil water suction. The results are shown in Table 1.

[0040] Table 1 Evaluation of soil water holding capacity under different humic acid solution addition conditions Depend on Figure 3 and Figure 4 As can be seen from Table 1, the humic acid solution prepared in Example 1 has the fastest penetration speed in the horizontal and vertical directions of the white pulp soil, and can effectively penetrate the soil plough layer and directly act on the white pulp area of ​​the bottom layer, thus achieving targeted repair of the white pulp soil. It also simplifies and saves the investment in large-scale machinery, and can solve the white pulp problem of the soil from the source.

[0041] Test Example 2: Application of humic acid-based water-soluble fertilizer in improving albic soil Location: Shuguang Farm, Huanan County, Jiamusi City The basic physical and chemical properties of the soil are: bulk density 1.33, field water holding capacity 275.36 g / Kg, capillary porosity 39.87%, organic matter content 25.2 g / Kg, pH 5.92, total nitrogen 0.62 g / Kg, ammonium nitrogen content 24.8 mg / kg, available phosphorus content 16.6 mg / kg, and available potassium content 121.4 mg / kg.

[0042] The experiment set up 4 treatment groups: blank control group (CK), Example 2 group, comparative example 6 group, and comparative example 7 group. The blank control group was applied with an equal amount of clean water, Example 2 group was applied with the humic acid water-soluble fertilizer prepared in Example 2, and comparative examples 6 and 7 groups were respectively applied with the water-soluble fertilizer prepared in comparative examples 6 and 7. Each treatment was divided into 3 replicate plots, with a total of 12 plots of equal area, and the area of ​​each plot was 222.22m 2 .

[0043] The test variety is Demeya, with a growth period of 110 days. There are 6 rows of corn, a planting density of about 85,000 plants / hectare, and corn seeds are buried at a depth of 5 cm. On the 15th day of the corn growth period, each group of humic acid water-soluble fertilizers were watered, and watered once every 20 days. The humic acid water-soluble fertilizer was diluted with water at a volume concentration of 0.05%. After the aqueous solution was made, it was sprayed at a dosage of 750 liters per hectare between 2 pm and 4 pm. After the corn matured, the corn yield was determined by random sampling. The results are shown in Table 2. At harvest, 20-40 cm soil samples were collected, and the soil bulk density was determined by the ring knife method, the soil specific gravity was determined by the hydrometer method, and the soil porosity was calculated. The soil organic matter was determined by potassium dichromate-ferrous sulfate titration method. The results are shown in Figures 5 to 7 The wet sieving method was used to determine the water-stable aggregate content of the soil. The results are shown in Table 3.

[0044] Table 2 Corn yield and yield components under different treatments Table 3 Effects of different treatments on soil water-stable aggregates Note: Different lowercase letters indicate significant differences (P < 0.05).

[0045] From Tables 2~3 and Figures 5 to 7 It can be seen that the humic acid water-soluble fertilizer prepared in Example 2 can not only increase corn yield, but also reduce the porosity of white soil, increase soil bulk density and organic matter content, thereby achieving targeted repair of white soil and providing sufficient nutrients for plant growth, thereby achieving rapid improvement of white soil.

[0046] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A humic acid solution, characterized in that: The preparation method of the humic acid solution is: A silane coupling agent is added to the solution containing humic acid, heated and stirred, and then tannic acid and lecithin are added dropwise respectively under heat preservation, and after the addition is completed, the reaction is continued to obtain a humic acid solution.

2. The humic acid solution according to claim 1, characterized in that The solution containing humic acid is a sodium humate solution, and its preparation method is as follows: The raw material containing humic acid is crushed and impurities are removed to obtain a pretreated raw material, the pretreated raw material is mixed with water to obtain a mixed solution, an alkali containing sodium is added, heated and stirred for reaction, and solid-liquid separation is performed after the reaction to obtain a sodium humate solution.

3. The humic acid solution according to claim 2, characterized in that: The mass ratio of the pretreated raw material to water is 1:1.4; the alkali containing sodium is NaOH solution or Na2CO3 solution; the mass ratio of the alkali containing sodium to the mixed solution is 1:

5.

4. The humic acid solution according to claim 2, characterized in that The raw material containing humic acid is weathered coal or lignite; the heating temperature is 30-35° C.; and the stirring reaction time is 30-40 minutes.

5. The humic acid solution according to claim 1, characterized in that: The heating and stirring temperature is 50-70°C and the time is 10-30 min; the continued reaction time is 10-30 min.

6. The humic acid solution according to claim 1, characterized in that The mass ratio of the solution containing humic acid, the silane coupling agent, tannic acid and lecithin is 100:5-10:2-4:2-4.

7. The humic acid solution according to claim 1, characterized in that The silane coupling agent is KH560; the dropping speed is 1-3 mL / min.

8. Use of the humic acid solution according to any one of claims 1 to 7 in rapidly penetrating white clay or preparing humic acid-based water-soluble fertilizer.

9. A humic acid-based water-soluble fertilizer for rapid improvement of albic soil, characterized in that: The humic acid-based water-soluble fertilizer contains the humic acid solution according to any one of claims 1 to 7.

10. The humic acid-based water-soluble fertilizer according to claim 9, characterized in that: The humic acid-based water-soluble fertilizer also contains the following raw materials: 145~170g / L urea, 115~155g / L monoammonium phosphate, 95~115g / L potassium chloride, 0.5~1.5 g / L zinc sulfate, 0.5~1.5 g / L ferrous sulfate, 0.5~1.5 g / L manganese sulfate, 0.5~1.5 g / L copper sulfate, 0.5~2g / L rare earth elements, 0.5~1.5g / L defoamer, 1.0~6.5 g / L thickener.

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