Method for restoring soil in photovoltaic field area through camellia oleifera

Abstract

The invention relates to the technical field of soil improvement and soil pollution treatment, in particular to a method for restoring soil in a photovoltaic field area through camellia oleifera. According to the method, camellia oleifera shell biomass charcoal and magnesium salt modified camellia oleifera shell biomass charcoal are used as soil improvement agents, the use amount of the soil improvement agents is regulated, and a proper camellia oleifera planting mode is adopted, so that even if a nitrogen fertilizer is not used, the soil acidification phenomenon in a photovoltaic field area cannot be deteriorated while the survival rate of camellia oleifera is increased; the physicochemical property, microbial activity, carbon sequestration, soil conservation and water conservation functions of the soil in the photovoltaic field area can be further improved.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement and soil pollution control, and in particular to a method for repairing photovoltaic field soil by using oil-tea camellia. Background Art

[0003] The construction and operation of photovoltaic power stations will inevitably have an impact on the stability of the local ecosystem. This is mainly manifested in the fact that the construction of photovoltaic power stations will change, damage or bury the original landforms and vegetation types, resulting in surface exposure, reducing the soil fixation and anti-erosion capabilities of the original landforms and vegetation, and exacerbating soil erosion. In addition, the impact of photovoltaic systems on local carbon storage is also closely related to the original vegetation conditions and soil utilization types. Therefore, when vigorously developing photovoltaic power generation projects, we must pay close attention to the soil ecological environment and strengthen its ecological reconstruction and ecological protection.

[0004] To improve the soil environment in the photovoltaic field, we can consider planting dwarf plants - Camellia oleifera. Camellia oleifera is widely distributed in China's subtropical regions and is one of the main edible oil woody plants. Camellia oleifera and its by-products play an important role in agriculture, industry, medicine and other fields. Planting dwarf plants - Camellia oleifera in photovoltaic fields can protect and tighten the soil, reduce or avoid soil erosion, and absorb, enrich, fix and degrade pollutants in the soil and water (including groundwater), thereby increasing the carbon storage of photovoltaic fields.

[0005] However, in the process of growing tea oil, there are often problems such as the loss of basic cations and the large-scale application of nitrogen fertilizers, which leads to a decrease in pH buffer capacity and gradual acidification of the soil, further aggravating the deterioration of the soil environment in the photovoltaic field. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems in the prior art that the soil environment in photovoltaic areas is poor and planting camellia oleifera is likely to further deteriorate the existing soil environment, and to provide a method for repairing the soil in photovoltaic areas with camellia oleifera. The method can improve the survival rate of camellia oleifera without using nitrogen fertilizer and will not aggravate the acidification of the soil in photovoltaic areas, thereby further improving the soil environment in photovoltaic areas.

[0007] In order to achieve the above-mentioned object, the present invention provides a method for repairing the soil in a photovoltaic field by using oil-tea camellia, which method comprises: improving the soil in the photovoltaic field and planting oil-tea camellia;

[0008] (1) Soil improvement treatment in photovoltaic areas includes:

[0009] (1-1): After the photovoltaic field area is tilled to 20-30 cm from the ground surface, the first soil conditioner is used to perform the first soil improvement treatment;

[0010] (1-2): After 10-30 days, the photovoltaic field area is tilled to 40-60 cm from the ground surface, and the second soil conditioner is used to improve the soil;

[0011] Wherein, the first soil conditioner is camellia oleifera shell biochar, and the dosage is 50-200 kg / mu; the pore size of the camellia oleifera shell biochar is greater than 45 nm, and the total pore volume is 0.002-0.005 cm / g;

[0012] The second soil conditioner is magnesium salt-modified camellia shell biochar, with an amount of 100-300 kg / mu;

[0013] (2) Oil tea planting includes: 5-10 days after the soil is improved, oil tea is planted in the improved photovoltaic field soil using the hole planting method, with a planting density of 80-200 trees / mu.

[0014] By adopting the above technical scheme, by adjusting the type and amount of soil conditioners and adopting appropriate tea oil planting methods, even without using nitrogen fertilizer, the survival rate of tea oil can be improved without aggravating the acidification of soil in the photovoltaic field. It can further improve the physical and chemical properties, microbial activity, carbon fixation, soil conservation and water conservation functions of the soil in the photovoltaic field. DETAILED DESCRIPTION

[0015] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0016] On one hand, the present invention provides a method for repairing the soil in a photovoltaic field by using oil-tea camellia, the method comprising: improving the soil in the photovoltaic field and planting oil-tea camellia;

[0017] (1) Soil improvement treatment in photovoltaic areas includes:

[0018] (1-1): After the photovoltaic field area is tilled to 20-30 cm from the ground surface, the first soil conditioner is used to perform the first soil improvement treatment;

[0019] (1-2): After 10-30 days, the photovoltaic field area is tilled to 40-60 cm from the ground surface, and the second soil conditioner is used to improve the soil;

[0020] Wherein, the first soil conditioner is camellia oleifera shell biochar, and the dosage is 50-200 kg / mu; the pore size of the camellia oleifera shell biochar is greater than 45 nm, and the total pore volume is 0.002-0.005 cm / g;

[0021] The second soil conditioner is magnesium salt-modified camellia shell biochar, with an amount of 100-300 kg / mu;

[0022] (2) Oil tea planting includes: 5-10 days after the soil is improved, oil tea is planted in the improved photovoltaic field soil using the hole planting method, with a planting density of 80-200 trees / mu.

[0023] In the present invention, the soil improvement process may also include cleaning and leveling gravel and garbage on the surface of the photovoltaic field.

[0024] In the present invention, the photovoltaic field soil improvement treatment may include laying an improver on the photovoltaic field soil surface after soil turning treatment, and then turning the soil again. During the soil turning process, watering treatment may be carried out in a timely and appropriate amount according to the current status of the soil environment.

[0025] In the present invention, the soil remediation efficiency can be further improved by reasonably regulating the dosage of the two soil conditioners. Preferably, the dosage of the first soil conditioner is 100-150 kg / mu; the dosage of the second soil conditioner is 150-200 kg / mu.

[0026] In the present invention, controlling the planting density of oil tea can further improve the survival rate of oil tea in the photovoltaic field, thereby achieving the effect of improving the soil environment of the photovoltaic field. Preferably, the planting density of the oil tea is 100-150 trees / acre.

[0027] Biochar is a kind of charcoal used as a soil conditioner. Biochar produced by high-temperature anaerobic (oxygen-limited) carbonization has good effects in adsorbing heavy metals in contaminated soil, fertilizing low-yield farmland and purifying water bodies. At the same time, the carbonization temperature, constant temperature time and carbonization material greatly affect the physical and chemical properties of biochar, and thus determine the functional characteristics of biochar. In the present invention, preferably, the oil tea shell biochar is obtained by carbonizing the oil tea shell; the conditions of the carbonization treatment include: pressure of 0.1-0.5MPa, temperature of 450-650℃, and time of 2-6h.

[0028] In the present invention, in order to prepare tea oil shell biomass charcoal with better soil remediation effect by reasonably controlling the carbonization conditions, preferably, the carbonization treatment conditions include: pressure of 0.1-0.3MPa, temperature of 500-600°C, and time of 4-6h.

[0029] In the present invention, preferably, the carbonization treatment includes sequentially crushing and drying the camellia oleifera shells.

[0030] According to a preferred embodiment, the pulverization process comprises pulverizing the camellia oleifera shell to a particle size of 1-5 mm, preferably 2-4 mm, for example, 2 mm, 3 mm, 4 mm and any range therebetween.

[0031] According to another preferred embodiment, the drying treatment conditions include: a temperature of 50-70°C, preferably 55-65°C, and a time of 2-6h, preferably 2.5-5.5h.

[0032] In the present invention, in order to improve the soil remediation effect of the camellia shell biochar, preferably, the pore size of the camellia shell biochar is 50nm-100nm, and the total pore volume is 0.003-0.004cm / g. For example, the pore size of the camellia shell biochar can be 50nm, 60nm, 65nm, 70nm, 80nm, 90nm, 100nm and the like and the range between any values ​​thereof; the total pore volume of the camellia shell biochar can be 0.0030cm / g, 0.0031cm / g, 0.0032cm / g, 0.0033cm / g, 0.0034cm / g, 0.0035cm / g, 0.0036cm / g, 0.0037cm / g, 0.0038cm / g, 0.0039cm / g, 0.0040cm / g and the range between any values ​​thereof.

[0033] In the present invention, preferably, the magnesium salt-modified camellia oleifera shell biomass charcoal is obtained by mixing the camellia oleifera shell biomass charcoal with a magnesium salt solution, and then drying and roasting the mixed mixture in sequence.

[0034] In the present invention, preferably, the magnesium salt solution has a mass fraction of 10-60wt%, preferably 15-35wt%, for example, it can be 15wt%, 20wt%, 25wt%, 30wt%, 35wt% and the like and any range between them. More preferably, based on the mass of the camellia shell biochar, the amount of the magnesium salt solution is 1-10wt%, preferably 5-8wt%, for example, it can be 5wt%, 6wt%, 7wt%, 8wt% and the like and any range between them.

[0035] In the present invention, preferably, the magnesium salt is selected from one or more of magnesium sulfate, magnesium chloride and magnesium nitrate.

[0036] In the present invention, preferably, the mixing treatment conditions include: temperature of 20-50°C, preferably 30-45°C, and time of 10-30h, preferably 12-24h.

[0037] In the present invention, preferably, the conditions of the drying treatment include: a temperature of 50-120° C., preferably 60-100° C., and a time of 3-10 h, preferably 2-8 h.

[0038] In the present invention, preferably, the conditions of the calcination treatment include: a temperature of 700-1200° C., preferably 850-1000° C., and a time of 0.5-3 h, preferably 1-2 h.

[0039] In the present invention, under preferred circumstances, the hole planting method for planting tea oil includes: digging planting holes in the improved photovoltaic field soil, backfilling the topsoil, and then planting tea oil seedlings.

[0040] In the present invention, digging a planting hole may include digging a hole around the predetermined planting point before planting the oil tea. The size of the planting hole should be determined according to the size of the oil tea, and should be able to accommodate all the roots of the oil tea and spread out. Avoid planting too deep or too shallow, which will hinder the growth of the oil tea.

[0041] By adopting the technical scheme described in the present invention, by regulating the type and amount of soil conditioner and adopting a suitable oil-tea camellia planting method, even without using nitrogen fertilizer, the survival rate of oil-tea camellia is not less than 75% and 70% after half a year and one year respectively, and the soil pH of the photovoltaic field area after one year of restoration is 6.29-6.57, the soil environment is not further acidified and the soil environment is greatly improved.

[0042] The present invention will be described in detail below through examples.

[0043] The photovoltaic field was divided into a number of square plots with an area of ​​1 mu (side length of about 25.8 m), and soil remediation work was carried out in different plots according to the method described in the embodiment.

[0044] Preparation Example 1

[0045] This preparation example is used to illustrate the preparation method of camellia oleifera shell biomass charcoal a1-a3.

[0046] The preparation of camellia oleifera shell biochar a1 includes: crushing the camellia oleifera shell to 2 mm and drying it at 55°C for 3 hours, and then carbonizing it at 0.1 MPa and 550°C for 5 hours to obtain camellia oleifera shell biochar a1. After identification, its average pore diameter is 60 nm and the total pore volume is 0.0032 cm / g.

[0047] The preparation of camellia oleifera shell biochar a2 includes: crushing the camellia oleifera shell to 4 mm and then drying it at 65°C for 5 hours, and then carbonizing it at 0.15 MPa and 600°C for 6 hours to obtain camellia oleifera shell biochar a2. After identification, the pore size of camellia oleifera shell biochar a2 is 65 nm and the total pore volume is 0.0035 cm / g.

[0048] The preparation of the camellia oleifera shell biomass charcoal a3 includes: crushing the camellia oleifera shell to 5 mm and then drying it at 55° C. for 3 hours, and then carbonizing it at 0.4 MPa and 450° C. for 2 hours to obtain the camellia oleifera shell biomass charcoal a3.

[0049] Preparation Example 2

[0050] This preparation example is used to illustrate the preparation method of modified camellia oleifera shell biomass charcoal b1, b2, b4, and b'1.

[0051] The preparation of modified camellia oleifera shell biomass charcoal b1 includes: mixing camellia oleifera shell biomass charcoal a1 with a 30wt% magnesium sulfate aqueous solution (the amount used is 5wt% of the camellia oleifera shell biomass charcoal) at 30°C for 12h, and then drying at 60°C for 6h and calcining at 850°C for 1h to obtain modified camellia oleifera shell biomass charcoal b1.

[0052] The preparation of modified camellia oleifera shell biomass charcoal b2 includes: mixing camellia oleifera shell biomass charcoal a2 with an aqueous solution of magnesium sulfate (mass fraction of 20wt%; amount of 8wt% of the camellia oleifera shell biomass charcoal) at 35°C for 15h, and then drying at 80°C for 8h and calcining at 1000°C for 1.5h to obtain modified camellia oleifera shell biomass charcoal b2.

[0053] The preparation of modified camellia oleifera shell biomass charcoal b4 includes: mixing camellia oleifera shell biomass charcoal a1 with an aqueous solution of magnesium sulfate (mass fraction of 15wt%; dosage is 3wt% of the camellia oleifera shell biomass charcoal) at 20°C for 10h, and then drying at 50°C for 6h and calcining at 700°C for 0.5h to obtain modified camellia oleifera shell biomass charcoal b4.

[0054] The preparation of the modified camellia oleifera shell biomass charcoal b'1 comprises: mixing the camellia oleifera shell biomass charcoal a1 and 0.1 mol L 1 The NaOH solution (the dosage is 10wt% of the camellia oleifera shell biomass charcoal) was mixed and treated at 30°C for 12h, and then dried at 60°C for 6h and calcined at 850°C for 1h to obtain modified camellia oleifera shell biomass charcoal b'1.

[0055] Example 1

[0056] This embodiment is used to illustrate the method of repairing soil in photovoltaic areas with camellia oleifera.

[0057] (1) Soil improvement treatment in photovoltaic areas includes:

[0058] (1-1): After the photovoltaic field area is tilled to 20 cm from the ground surface, the soil is first improved using camellia shell biochar a1, with the amount of camellia shell biochar a1 being 100 kg / mu;

[0059] (1-2): After 20 days, the photovoltaic field was tilled to 40 cm from the ground surface, and the soil was subjected to a second soil improvement treatment using modified camellia oleifera shell biochar b1, with the amount of modified camellia oleifera shell biochar b1 being 150 kg / mu;

[0060] (2) Oil tea planting includes: 10 days after soil improvement, oil tea is planted in the improved photovoltaic field soil using the hole planting method, with a planting density of 100 trees per mu.

[0061] Example 2

[0062] This embodiment is used to illustrate the method of repairing soil in photovoltaic areas with camellia oleifera.

[0063] (1) Soil improvement treatment in photovoltaic areas includes:

[0064] (1-1): After the photovoltaic field area is tilled to 30 cm from the ground surface, the soil is first improved using camellia shell biochar a2, with the amount of camellia shell biochar a1 being 150 kg / mu;

[0065] (1-2): After 15 days, the photovoltaic field was tilled to 45 cm from the ground surface, and the soil was subjected to a second soil improvement treatment using modified camellia oleifera shell biochar b2. The amount of modified camellia oleifera shell biochar b1 was 200 kg / mu.

[0066] (2) Oil tea planting includes: 5 days after the soil improvement treatment, oil tea is planted in the improved photovoltaic field soil using the hole planting method, with a planting density of 150 trees per mu.

[0067] Example 3

[0068] A similar method to Example 1 is used, except that the same amount of camellia oleifera shell biomass charcoal a3 is used to replace the camellia oleifera shell biomass charcoal a1.

[0069] Example 4

[0070] A similar method to Example 1 is used, except that the same amount of modified camellia oleifera shell biomass charcoal b4 is used to replace the modified camellia oleifera shell biomass charcoal b1.

[0071] Example 5

[0072] A similar method to Example 1 was used, except that the amount of the camellia oleifera shell biomass charcoal a1 was 50 kg / mu, and the amount of the modified camellia oleifera shell biomass charcoal b1 was 100 kg / mu.

[0073] Example 6

[0074] A similar method to Example 1 was used, except that the amount of the camellia oleifera shell biomass charcoal a1 was 200 kg / mu, and the amount of the modified camellia oleifera shell biomass charcoal b1 was 300 kg / mu.

[0075] Comparative Example 1

[0076] A similar method to Example 1 is used, except that the second soil remediation agent is alkali-modified Camellia oleifera shell biomass charcoal b'1.

[0077] Comparative Example 2

[0078] A similar method to Example 1 was used, except that the second soil conditioner was 150 kg / mu of camellia oleifera shell biochar a1.

[0079] Comparative Example 3

[0080] A similar method to Example 1 was used, except that the amount of the camellia oleifera shell biomass charcoal a1 was 30 kg / mu, and the amount of the modified camellia oleifera shell biomass charcoal b1 was 50 kg / mu.

[0081] Test Example 1

[0082] The number of surviving Camellia oleifera trees was recorded half a year and one year after applying the soil remediation methods described in the embodiment and the comparative example, and the survival rate of Camellia oleifera trees was calculated, as shown in Table 1.

[0083] Test method: Plant survival rate = (number of surviving plants / total number of planted plants) x 100%.

[0084] Table 1

[0085] Example No. Survival rate after half a year / % Survival rate after one year / % Example 1 84.3 82.5 Example 2 82.1 80.9 Example 3 75.6 73.6 Example 4 74.3 72.1 Example 5 76.1 74.8 Example 6 77.6 75.3 Comparative Example 1 61.4 59.8 Comparative Example 2 63.6 61.8 Comparative Example 3 65.3 62.3

[0086] Test Example 2

[0087] The effects of the soil remediation methods described in the above embodiments and comparative examples were verified, and the physical and chemical properties of the soil in the photovoltaic field area before and after the application of the method were detected, as shown in Table 2.

[0088] Test method:

[0089] 1. Soil pH and Eh determination: Take 1.0g soil sample, add 5ml deionized water (soil-water ratio is 1:5), mix well, put it into a constant temperature oscillator, oscillate at 220r / min at room temperature for 1 hour, take it out and let it stand for 30min, then measure: redox potential meter.

[0090] 2. Determination of soil organic carbon content: potassium dichromate oxidation and spectrophotometry (HJ615.2011).

[0091] 3. Determination of total nitrogen content: weigh an appropriate amount of sample into a digestion test tube, add 5mL of concentrated sulfuric acid and 3 drops of perchloric acid, cover with a funnel to prevent splashing at high temperature, place in a 400℃ digestion furnace to digest for 15 minutes, cool, add 1mL of 30% hydrogen peroxide solution to continue digestion, repeat this process until the digestion liquid is milky white. After the digestion liquid is cooled, wash it into a volumetric flask with ultrapure water, shake it after dilution, take the supernatant and save it for the determination of total nitrogen. The total nitrogen determination is determined by a fully automatic intermittent analyzer.

[0092] Table 2

[0093]

[0094]

[0095] It can be seen from the results in Table 1 and Table 2 that, compared with Comparative Examples 1-3, the photovoltaic field area repaired by the soil remediation method required in Examples 1-6 of the present invention has a more suitable pH, Eh, organic carbon and TN content and a higher survival rate of Camellia oleifera, especially when the remediation method required in Examples 1 and 2 is applied, the repaired soil environment is more excellent.

[0096] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for repairing soil in photovoltaic areas with oil-tea camellia, characterized in that: The method comprises: soil improvement treatment and oil-tea camellia planting in photovoltaic field areas; (1) Soil improvement treatment in photovoltaic areas includes: (1-1): After the photovoltaic field area is tilled to 20-30 cm from the ground surface, the first soil conditioner is used to perform the first soil improvement treatment; (1-2): After 10-30 days, the photovoltaic field area is tilled to 40-60 cm from the ground surface, and the second soil conditioner is used to improve the soil; Wherein, the first soil conditioner is camellia oleifera shell biochar, and the dosage is 50-200 kg / mu; the pore size of the camellia oleifera shell biochar is greater than 45 nm, and the total pore volume is 0.002-0.005 cm / g; The second soil conditioner is magnesium salt-modified camellia shell biochar, with an amount of 100-300 kg / mu; (2) Oil tea planting includes: 5-10 days after the soil is improved, oil tea is planted in the improved photovoltaic field soil using the hole planting method, with a planting density of 80-200 trees / mu.

2. The method according to claim 1, wherein: The dosage of the first soil conditioner is 100-150 kg / mu; the dosage of the second soil conditioner is 150-200 kg / mu; Preferably, the planting density of the oil tea is 100-150 trees / acre.

3. The method according to claim 1 or 2, wherein: The camellia oleifera shell biomass charcoal is obtained by carbonizing the camellia oleifera shell; the carbonization treatment conditions include: a pressure of 0.1-0.5 MPa, a temperature of 450-650° C., and a time of 2-6 hours; Preferably, the carbonization treatment conditions include: pressure of 0.1-0.3 MPa, temperature of 500-600° C., and time of 4-6 h.

4. The method according to any one of claims 1 to 3, wherein: The carbonization treatment includes crushing and drying the camellia oleifera shells in sequence; Preferably, the pulverizing process comprises pulverizing the camellia oleifera shell to a particle size of 1-5 mm, preferably 2-4 mm; More preferably, the drying treatment conditions include: a temperature of 50-70°C, preferably 55-65°C, and a time of 2-6h, preferably 2.5-5.5h.

5. The method according to any one of claims 1 to 4, wherein: The pore size of the camellia oleifera shell biomass charcoal is 50nm-100nm, and the total pore volume is 0.003-0.004cm / g.

6. The method according to any one of claims 1 to 5, wherein: The magnesium salt-modified camellia oleifera shell biomass charcoal is obtained by mixing the camellia oleifera shell biomass charcoal with a magnesium salt solution, and then drying and roasting the mixture in sequence.

7. The method according to any one of claims 1 to 6, wherein: The magnesium salt solution has a mass fraction of 10-60wt%, preferably 15-35wt%; Preferably, based on the mass of the camellia oleifera shell biomass charcoal, the amount of the magnesium salt solution is 1-10wt%, preferably 5-8wt%; Preferably, the magnesium salt is selected from one or more of magnesium sulfate, magnesium chloride and magnesium nitrate.

8. The method according to any one of claims 1 to 7, wherein: The mixing treatment conditions include: temperature of 20-50°C, preferably 30-45°C, and time of 10-30h, preferably 12-24h.

9. The method according to any one of claims 1 to 8, wherein: The drying conditions include: a temperature of 50-120°C, preferably 60-100°C, and a time of 3-10h, preferably 2-8h; And / or, the calcination treatment conditions include: a temperature of 700-1200° C., preferably 850-1000° C., and a time of 0.5-3 h, preferably 1-2 h.

10. The method according to any one of claims 1 to 9, wherein: The hole planting method for planting tea oil includes: digging planting holes in the improved photovoltaic field soil, backfilling the topsoil, and then planting tea oil seedlings.

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