A method for preparing recycled planting soil from river dredging soil

Abstract

This invention discloses a method for preparing recycled planting soil from river dredging soil. First, 0.5-1% wt quicklime and 20-30 g / cubic meter of chloropicrin are mixed into low-moisture dredging soil cake, then covered with a film and left to stand at room temperature for 3-4 days to allow the ash to settle. Next, 1-2% wt wood ash, 1-3‰ wt indoleacetic acid, and 3-6% wt magnesium peroxide are mixed into the sterilized dredging soil. Finally, a soil layer structure is laid, thereby creating a planting environment that promotes plant root growth. This invention's preparation method is simple, resource-efficient, and environmentally friendly. It effectively solves the problems of low plant survival rates and slow growth when dredging soil is directly used for planting, and alleviates many problems associated with storing dredging soil.

Description

Technical Field

[0001] This invention relates to the field of engineering waste soil recycling and planting soil preparation technology, specifically to a method for preparing recycled planting soil from river dredging soil. Background Technology

[0002] Dredged soil possesses the basic characteristics of general planting soil, such as providing support, buffering, and nutrients for plants. However, due to defects in its physical and chemical properties, dredged soil suffers from severe compaction and oxygen deficiency, leading to weakened root respiration, decreased vitality, and reduced capacity for fertilizer and water absorption. This, in turn, makes crops prone to nutrient deficiencies, resulting in low survival rates and slow growth. Therefore, dredged soil must undergo necessary treatment before it can be reused as planting soil. However, to date, very little information is available about dredged soil.

[0003] The method for ecologically solidifying dredged soil by planting specific plants disclosed in application number 202010795344.1 includes leveling the dredging and reclamation site, planting emergent plants, opening drainage channels, and planting grasses. However, this patent has shortcomings such as limited types of plants that can be planted and the need to reasonably adjust the planting space.

[0004] The application number 202011621882.5 discloses a river silt-based landscaping soil, which contains 60-85% alkaline river silt, 2-10% furfural residue, 10-30% straw powder, 0.5-2% fermented and decomposed straw powder residue, and 5-8% chitosan. However, this patent requires adjustment of the proportions of each component based on the C / N ratio, which is costly and time-consuming.

[0005] Application number 201811331649.6 discloses a method for preparing landscaping soil using urban sewage sludge. First, rice husks, microbial inoculum, and microbial residue are added to the urban sewage sludge and mixed thoroughly. The mixture is then fermented in a ventilated environment at 45-60℃ for 5-7 days. The mixture is then turned over, and the moisture content is controlled at 50-60%. After 5-7 days, mineral materials, biochar, and soil conditioners are added, and the mixture is stirred thoroughly. It is then fermented in a ventilated environment at 45-60℃ for 5-7 days, with the moisture content controlled at 25-35%, ultimately yielding landscaping soil. This patent involves complex raw material components and a lengthy preparation process for the landscaping soil.

[0006] In order to broaden the application of dredged soil and reduce resource waste, it is necessary to improve its treatment. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing recycled planting soil from river dredging soil, which solves the problems of land occupation and inability to be directly used due to the current high water content of dredging soil. It is applicable to environmental greening projects, can realize the recycling of dredging soil and promote environmental friendliness, and has significant social and economic benefits.

[0008] To solve the problems of the prior art, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing regenerated planting soil from river dredging soil includes the following steps: Step 1, sterilization and disinfection; Step 2, topdressing and oxygenation; Step 3, laying out the following layers from top to bottom: a planting soil layer, an oxygen-enriching and heat-insulating soil layer, a water-conducting and water-retaining soil layer, and absorbent fiber cotton, to obtain the regenerated planting soil; wherein, the planting soil layer is made of sterilized and disinfected cohesive dredged soil treated in Step 1, used to retain water and maintain soil moisture; the oxygen-enriching and heat-insulating soil layer is made of topdressed and oxygen-enriched dredged soil treated in Step 2, used to ensure the nutrients and temperature required for plant seed germination and plant growth; and the water-conducting and water-retaining soil layer is made of sterilized and disinfected sandy dredged soil treated in Step 1, to continuously provide water for plant growth and prevent nutrient loss.

[0010] As an improvement, the sterilization and disinfection steps are as follows: 0.5-1%wt quicklime and 20-30g / cubic meter of chloropicrin are mixed into the dredged soil cake with low moisture content, then covered with a film and piled at room temperature for 3-4 days to achieve the effect of eliminating pathogenic microorganisms and loosening the soil.

[0011] A further improvement is that the sterilization and disinfection step is as follows: the moisture content of the low-moisture dredged soil cake is 30%-45%.

[0012] As an improvement, the specific steps of the topdressing and oxygenation are as follows: 1-2%wt of wood ash, 1-3‰wt of indoleacetic acid and 3-6%wt of magnesium peroxide are mixed into the sterilized and dredged soil to create a planting environment that promotes plant root growth. Since wood ash is rich in elements such as nitrogen, phosphorus and potassium for plant growth, indoleacetic acid can promote root development, and magnesium peroxide can release oxygen and heat slowly over a long period of time, the base fertilizer can moisten the soil, increase oxygen and keep the soil warm.

[0013] As an improvement, the thickness of the planting soil layer is 3-5cm; the thickness of the oxygen-enriching and heat-insulating soil layer is 8-10cm; and the thickness of the water-conducting and water-storing soil layer is 10-15cm. Beneficial effects

[0014] Compared with existing technologies, the method for preparing recycled planting soil from river dredging soil of the present invention has the following advantages:

[0015] (1) Achieve harmless recycling of dredged soil, saving resources and being environmentally friendly;

[0016] (2) A new preparation method is provided for regenerating green planting soil from dredged soil;

[0017] (3) Local planting, simple process, low cost, and short recycling time. Attached Figure Description

[0018] Figure 1Attached diagram of soil structure;

[0019] Figure 2 A photograph of the dredged soil used for growing bok choy using the recycled planting soil of this invention.

[0020] Figure 3 This is a flowchart of a method for preparing recycled planting soil from river dredging soil according to the present invention. Implementation

[0021] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0022] A method for preparing recycled planting soil from river dredging soil includes the following steps:

[0023] (1) First, crush the mud cakes from the river dredging, mix in 0.5-1%wt quicklime and 20-30g / cubic meter of chloropicrin, cover with film and pile at room temperature for 3-4 days to eliminate pathogenic microorganisms and loosen the soil.

[0024] (2) Then mix 1-2%wt of wood ash, 1-3‰wt of indoleacetic acid and 3%-6%wt of magnesium peroxide into the sterilized and disinfected dredged soil to create a planting environment that promotes plant root growth. Wood ash is rich in elements such as nitrogen, phosphorus and potassium for plant growth, indoleacetic acid can promote root development, and magnesium peroxide can release oxygen and heat slowly over a long period of time, thus achieving the effects of basal fertilizer moistening the soil, increasing oxygen and keeping warm.

[0025] (2) First, lay a 3-5cm thick layer of sterilized and disinfected cohesive dredged soil as the planting soil layer to achieve water retention and moisture preservation. Then, cover it with an 8-10cm thick layer of topdressing and oxygenation as the dredged soil oxygenation and heat preservation soil layer to ensure the nutrients and temperature required for plant seed germination and plant growth. Finally, lay a 10-15cm thick layer of sterilized and disinfected sandy dredged soil as the water-conducting and water-retaining soil layer, and place a layer of fiber absorbent cotton underneath to continuously provide water for plant growth and prevent nutrient loss. Example

[0026] Taking dredged silt as an example, in order to regenerate it into planting soil for green plants, the dredged soil cake is first crushed, and 0.5% wt quicklime and 25g / cubic meter of chloropicrin are added. Then, it is covered with a film and piled at room temperature for 3 days to eliminate pathogenic microorganisms and loosen the soil.

[0027] Then, mix 2%wt wood ash, 2‰wt indoleacetic acid and 4%wt magnesium peroxide into the sterilized and disinfected dredged soil to create a planting environment that promotes plant root growth.

[0028] Finally, a 4cm thick layer of sterilized and disinfected cohesive dredged soil is laid as the planting soil layer to retain water and maintain soil moisture. Then, an 8cm thick layer of topdressing and oxygen-enriching dredged soil is laid to ensure the nutrients and temperature required for plant seed germination and plant growth. Finally, a 12cm thick layer of sterilized and disinfected sandy dredged soil is laid as the water-conducting and water-retaining soil layer, with a layer of fiber absorbent cotton underneath to continuously provide water for plant growth and prevent nutrient loss.

[0029] To compare and analyze the planting effects of regenerated silty soil under different treatment conditions, prepared silty soil planting boxes were used. Several *Hedysarum heterotropoides* seeds were sown in each box at 0.5 cm intervals. The boxes were sprayed with water until moist and placed on a well-lit and well-ventilated balcony. Water was sprayed every 8 hours to maintain moisture. Germination rates and growth of various plants were recorded and photographed at 3, 7, 14, and 21 days. The results are shown in Table 1. Figure 1 As shown.

[0030] Table 1. Statistical table of germination rate of green plants planted in recycled silt soil under different treatment conditions.

[0031] Table 1 shows that the germination time, growth rate, and vigor of plants in silty soil under different treatment conditions varied significantly. Among the four soil treatments, the soil treated with quicklime, chloropicrin, wood ash, indoleacetic acid, and magnesium peroxide had the highest germination rate at 86.7%. The soil treated with chloropicrin and the soil treated with quicklime and chloropicrin had the next highest germination rates at 61.5% and 78.6%, respectively. Plants treated with quicklime did not germinate at all during the entire growth cycle. Figure 1 It can be seen that after 3 days of planting, no sprouts emerged from the soil treated with quicklime and chloropicrin, while green shoots emerged from the soil treated with quicklime and chloropicrin, quicklime, chloropicrin, wood ash, indoleacetic acid, and magnesium peroxide, with the latter having a higher germination rate than the former. After 7 days of planting, the plants in the quicklime-treated soil and the chloropicrin-treated soil still had not sprouted, while the plants in the soil treated with quicklime and chloropicrin, quicklime, chloropicrin, wood ash, indoleacetic acid, and magnesium peroxide had all grown into small plants, with the latter growing at a slightly faster rate than the former. At 4 days, the plants in the quicklime-treated soil still had not sprouted, while the plants in the chloropicrin-treated soil had just begun to sprout green shoots. The plants in the quicklime and chloropicrin-treated soil, as well as those in the soil treated with quicklime, chloropicrin, wood ash, indoleacetic acid, and magnesium peroxide, were growing well, with the latter showing better overall growth than the former. At 21 days, the plants in the quicklime-treated soil still had not sprouted, while the plants in the chloropicrin-treated soil had grown into small plants. At the same time, the plants in the quicklime and chloropicrin-treated soil, as well as those in the soil treated with quicklime, chloropicrin, wood ash, indoleacetic acid, and magnesium peroxide, were growing well, with the latter showing significantly stronger growth than the former.

[0032] In summary, this invention treats dredged soil from river channels with quicklime, chloropicrin, wood ash, indoleacetic acid, and magnesium peroxide to achieve harmless recycling of the dredged soil, conserving resources and being environmentally friendly. Specifically, it eliminates pathogenic microorganisms and loosens the soil; then, it creates a planting environment that promotes plant root growth, thereby achieving the effects of basal fertilization, soil moistening, oxygenation, and heat preservation; finally, it designs a unique soil layer structure to achieve water retention and moisture preservation, ensuring the nutrients and temperature required for plant seed germination and plant growth, continuously providing water for plant growth, and preventing nutrient loss. It has good application prospects.

Claims

1. A method for preparing recycled planting soil from river dredging soil, characterized in that, Includes the following steps: Step 1: Sterilization and disinfection; Step 2: Topdressing and oxygenation; Step 3: Laying out the following layers from top to bottom: planting soil layer, oxygen-enriching and heat-insulating soil layer, water-conducting and water-retaining soil layer, and absorbent fiber cotton, to obtain the regenerated planting soil; wherein, the planting soil layer is made of sterilized and disinfected cohesive dredged soil treated in Step 1, used to retain water and maintain soil moisture; the oxygen-enriching and heat-insulating soil layer is made of topdressing and oxygen-enriching dredged soil treated in Step 2, used to ensure the nutrients and temperature required for plant seed germination and plant growth; the water-conducting and water-retaining soil layer is made of sterilized and disinfected sandy dredged soil treated in Step 1, to continuously provide water for plant growth and prevent nutrient loss; the sterilization and disinfection step is: mixing 0. After adding 5-1% wt quicklime and 20-30 g / cubic meter of chloropicrin, cover with a film and pile at room temperature for 3-4 days to eliminate pathogenic microorganisms and loosen the soil. The specific steps for topdressing and oxygenation are as follows: mix 1-2% wt wood ash, 1-3‰ wt indoleacetic acid, and 3-6% wt magnesium peroxide into the sterilized and dredged soil to create a planting environment that promotes plant root growth. Since wood ash is rich in nitrogen, phosphorus, and potassium elements for plant growth, indoleacetic acid promotes root development, and magnesium peroxide slowly releases oxygen and heat, it achieves the effects of basal fertilizer moistening the soil, oxygenation, and heat preservation. The thickness of the planting soil layer is 3-5 cm; the thickness of the oxygenation and heat preservation soil layer is 8-10 cm; and the thickness of the water-conducting and water-retaining soil layer is 10-15 cm.

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