Rapid method for improving structure of acidic clayey reclamation tea garden soil

Abstract

The application discloses a method for rapidly improving the structure of acid clay of newly reclaimed tea garden, and relates to the technical field of tea garden soil improvement.The method comprises the following steps: collecting the 0-20cm surface soil before the grass seeds mature in autumn, mixing the collected soil with lime for acidification improvement, covering the soil with a film for sterilization and weed killing; ploughing the soil after the surface soil is removed to a depth of 55-65cm, adding a biochar-based modifier according to the target soil pH value, and promoting soil maturation through dry-wet alternating measures; adding the biochar-based modifier to the surface soil after the surface soil is spread, and ploughing the surface soil to a depth of 55-65cm again; and planting rape, scattered chicory and wild peas in turn from before winter, and crushing the plants and ploughing the plants into the soil.The method effectively improves the acid clay problem commonly existing in the newly reclaimed tea garden at a low altitude, rapidly improves the soil acidity and soil fertility of the newly reclaimed tea garden, and improves the deep soil structure, so that good soil conditions are provided for the normal growth of young tea trees.

Description

Technical Field

[0001] This invention relates to the field of tea garden soil improvement technology, and in particular to a rapid method for improving the soil structure of acidic clay tea gardens undergoing recultivation. Background Technology

[0002] The soil types in tea gardens at lower altitudes are mainly yellow soil and red soil developed from Quaternary red clay parent material. The soil is acidic to strongly acidic, heavy in texture, and nutrient-poor. In production, when establishing tea gardens, the subsoil and topsoil are often directly tilled and mixed. This mixing of the entire soil undoubtedly exacerbates the existing problems of acidity, heavy texture, poor structure, and fertility in the topsoil of newly established tea gardens. This leads to air leakage and moisture loss during droughts, even causing root breakage, while waterlogging frequently occurs during periods of heavy rainfall, severely impacting the survival rate and normal growth of tea seedlings. Current techniques mostly focus on acidification improvement of the topsoil or the 0-40cm soil layer. However, tea tree roots are generally 60-80cm deep; shallow soil improvement is also detrimental to the later growth of tea tree roots.

[0003] Related technologies, such as Chinese Invention Patent Application Publication No. CN112703849A, disclose a method for improving soil in tea plantations, including the following steps: tea garden sanitation treatment → deep soil tillage treatment → multi-stage soil sterilization treatment → soil modification treatment → application of organic fertilizer. Specifically, it uses a composite sterilization method of sun-drying sterilization + greenhouse sterilization + incineration sterilization + chemical sterilization to sterilize soils used for long-term tea planting. It uses dolomite powder, locust leaves, and physiologically alkaline fertilizers to improve soil acidity, and combines this with the application of wood ash, corn stalks, and legume crop straw compost to achieve the purpose of soil improvement. However, this technology ignores the C / N ratio of soil conditioners and organic fertilizers. Plant-based conditioners and fertilizers often have a high C / N ratio, which can easily cause nitrogen fixation by microorganisms. Moreover, the incineration sterilization method is no longer suitable for current ecological environmental protection requirements. In addition, some acidic soil conditioners disclosed in related technologies are mainly composed of lime and mixtures of certain minerals or industrial by-products, posing a certain risk of heavy metal introduction.

[0004] The existing technology, "A Method for Constructing a High-Value Ecological Hilly Tea Garden" (Publication No. CN113854029A), discloses planting clover in newly reclaimed tea gardens and intercropping perennial forage grasses among the tea plants after transplanting. However, clover has high soil requirements, grows slowly in the early stages, and is prone to uneven emergence and management difficulties when planted in newly reclaimed land. Moreover, more than 81% of the clover's root system is distributed in the soil layer above 80cm, making it difficult to exert its effects on deeper soil layers. In addition, rotating tall grasses between rows after transplanting tea trees can easily lead to competition for nutrients with the tea trees. Alfalfa, commonly used in the existing technology, is suitable for growing in dry, warm, and sunny climates and neutral to slightly alkaline soils, and is difficult to adapt to the humid and rainy climate and acidic to strongly acidic soils of the main tea-producing areas.

[0005] In summary, current technologies for soil improvement in newly reclaimed tea gardens need further refinement to address the prevalent acidic and heavy soil conditions and provide favorable soil conditions for the normal growth of young tea trees.

[0006] Therefore, it is essential to develop a method for rapid soil structure improvement to address the common problem of acidic and heavy soil in newly established tea gardens at low altitudes, and to provide good soil conditions for the normal growth of young tea trees. Summary of the Invention

[0007] The purpose of this invention is to provide a rapid method for improving the soil structure of newly reclaimed tea gardens in acidic clayey soil, in order to solve the problems existing in the prior art, improve the common acidic clayey soil problem in newly reclaimed tea gardens at low altitudes, rapidly increase the soil acidity and fertility of newly reclaimed tea gardens, and improve the deep soil structure, so as to provide good soil conditions for the normal growth of young tea trees.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] One of the technical solutions of this invention is a method for rapidly improving the soil structure of acidic clay tea gardens, comprising the following steps:

[0010] Step 1: Collect the topsoil from 0-20cm, adjust its pH to 5.0-5.5, and then perform sterilization and weed control treatment to obtain the treated topsoil.

[0011] Step 2: Till the soil with the topsoil removed to a depth of 55-65cm, remove debris, and then test the soil pH value.

[0012] Step 3: Adjust the pH of the soil from Step 2 to 5.0-5.5 using a biochar-based amendment; adjust the soil moisture content from Step 2 to 70%-80% of field capacity; cover with a film to maintain soil moisture for one week; uncover the film to allow the soil to dry, and till once during this period to promote soil drying; repeat the above wet-drying alternation steps 3-4 times.

[0013] Step 4: Spread the topsoil treated in Step 1 evenly on the ground surface, apply biochar-based amendment, and till to a depth of 55-65cm.

[0014] Step 5: Rotate rapeseed, chicory and wild pea in sequence. After the rapeseed and chicory have finished growing, break up the above-ground parts of the plants and turn them into the soil. After the wild peas have finished growing, break up the above-ground parts of the plants and apply cake fertilizer and compound fertilizer. Plow to a depth of 55-65cm.

[0015] Furthermore, in step 1, the topsoil is collected before the grass seeds mature in September. Before collecting the topsoil, weeds, stones, and debris are cleaned up. The pH value of the topsoil is adjusted to 5.0-5.5 by adding lime. The topsoil is sterilized and weeded by covering it with a film.

[0016] Furthermore, in step 2, after removing debris, dig mutually perpendicular drainage ditches around the tea garden to be cultivated and inside the tea garden, and collect soil samples from the 0-40cm soil layer using a multi-point sampling method to test the soil pH value.

[0017] Further, in step 3, based on the measured soil acid buffering curve, calculate the amount of biochar-based amendment required to adjust the soil pH to 5.0-5.5; evenly spread the biochar-based amendment on the soil surface and till it to a depth of 40-50 cm; irrigate the soil to bring the soil moisture content to 70-80% of field capacity, cover it with a film to maintain soil moisture for 1 week, uncover the film to allow the soil to dry, and till it once during this period to promote soil drying; repeat this cycle of alternating wet and dry conditions 3-4 times.

[0018] Furthermore, in step 4, a biochar-based amendment is applied at a rate of 200 kg / mu to improve the fertility of the topsoil that has only undergone soil acidity adjustment and herbicide treatment, and to improve its soil structure.

[0019] Furthermore, in step 5, European rapeseed is sown in early November before winter, and the above-ground parts of the rapeseed plants are broken up and incorporated into the soil in March; then, chicory is sown, and its above-ground parts are broken up and incorporated into the soil in early September after its growth period; wild peas are sown in early September, and the above-ground parts of the wild peas are broken up in early November, with 3000 kg / hm² of cake fertilizer applied. 2 Compound fertilizer 750kg / hm 2 As base fertilizer, till the soil to a depth of 40-50cm.

[0020] Furthermore, step 5, after tilling, also includes digging planting trenches and planting tea seedlings.

[0021] Furthermore, the preparation method of the biochar-based modifier includes the following steps:

[0022] 1) Dissolve starch and potassium persulfate in water to obtain solution A; add potassium hydroxide, acrylamide and N,N-methylene-bisacrylamide to acrylic acid solution, heat and stir to obtain solution B; mix solution A and solution B to obtain a mixed solution; dissolve sodium carboxymethyl cellulose, xanthan gum and β-glucan in hot water to obtain solution C; mix solution C with the mixed solution, stir until gelatinous, air dry and then dry, pulverize and pass through a 100-mesh sieve to obtain biochar-based soil conditioner pre-mixed material;

[0023] 2) Mix peanut shell biochar, fermented plant-derived medicinal herb residue powder, shrimp shell powder, humic acid, calcium-based bentonite, vermiculite, the biochar-based soil conditioner pre-mixed material, and N-carboxymethyl acrylamide to obtain a mixture.

[0024] 3) Spray urea solution into the mixture to adjust the C / N ratio to 20-25 and the water content to 30-40%, mix and granulate; sieve and dry to a water content of 10% to obtain the biochar-based modifier.

[0025] In step 1), the amount of water used in solutions A and C is just enough to dissolve the solid raw materials.

[0026] Further, in step 1), the mass ratio of starch to potassium persulfate is 5g:1g; the temperature of solution A is 70℃; the mass ratio of potassium hydroxide, acrylamide, N,N-methylenebisacrylamide, and acrylic acid solution is 250:80:0.2:300; the concentration of acrylic acid solution is 0.45g / mL; the temperature of solution B is 70℃; the mass ratio of sodium carboxymethyl cellulose, xanthan gum, and β-glucan is 1:3:4; and the temperature of hot water is 70℃.

[0027] In step 2), the mass ratio of peanut shell biochar, fermented plant-derived medicinal residue powder, shrimp shell powder, humic acid, calcium-based bentonite, vermiculite, biochar-based soil conditioner pre-mixed material, and N-carboxymethyl acrylamide is 30-35:18-20:12-15:10-12:10-12:5-8:2-5:1-2;

[0028] In step 3), the sieving specifically refers to passing the material through a 4-6 mm sieve; the drying refers to freeze drying or cold air drying.

[0029] In step 1), starch, a natural polymer raw material, is first gelatinized in hot water at a suitable temperature, with a small amount of potassium persulfate added as an initiator for subsequent steps. Acrylic acid is the monomer of the target polymer. Appropriate potassium hydroxide is added to the acrylic acid solution to adjust the pH of the reaction system to a suitable range, then acrylamide is added, and a small amount of N,N-methylenebisacrylamide is used as a crosslinking agent for polymerization. Mixing the natural starch polymer with the acrylic acid and acrylamide polymers forms a raw material component with very strong adsorption capacity, which can significantly increase the adsorption performance of the biochar-based amendment. Furthermore, dissolving sodium carboxymethyl cellulose, xanthan gum, and β-glucan, which have cementing properties, in hot water enhances the cementing ability, significantly increasing the cementing effect of the biochar-based amendment on the soil, promoting the formation of aggregates and large aggregates, and improving the stability of the aggregates, thereby improving soil structure. By preparing the above-mentioned raw material components that require special reaction conditions separately and then mixing them, a pre-made biochar-based soil conditioner with water absorption and retention properties and the ability to promote the formation of aggregate structure can be obtained, which facilitates the large-scale and rapid preparation of subsequent biochar-based soil conditioners.

[0030] In step 2), calcium-based bentonite and vermiculite are added. The adsorption and swelling properties of the layered structure of calcium-based bentonite, as well as the abundant Ca in the interlayers, can be utilized. 2+ This increases the adsorption capacity of biochar-based amendments for soil moisture and nutrients, and further enhances the adsorption capacity of biochar-based amendments for soil nutrients by utilizing the strong ion exchange capacity of vermiculite, thus accelerating the improvement of soil fertility. In addition, both raw materials are natural and non-toxic minerals that exist in the soil, which improves the safety of the amendment.

[0031] The second technical solution of the present invention is a method for promoting the growth of the above-ground and underground parts of young tea trees, which uses the above-mentioned rapid improvement method of acidic clay tea garden soil structure to improve the soil for planting young tea trees.

[0032] The present invention discloses the following technical effects:

[0033] (1) Before reclamation, the topsoil is collected and treated separately. Although this increases the workload in the early stage, the topsoil with relatively abundant nutrients and organic matter is preserved. At the same time, it is convenient to improve the deep soil, improve soil acidity, and especially accelerate the maturation of deep soil, providing good soil conditions for the root growth of tea seedlings after the garden is established.

[0034] (2) The present invention cultivates the soil before the grass seeds mature in autumn, mixes lime into the topsoil, and covers it with a film for sterilization and weed control, which can reduce the germination of weeds after the establishment of tea garden, reduce weed damage in young tea gardens, and improve the survival rate of tea seedlings.

[0035] (3) The biochar-based amendment prepared in this invention is rich in alkaline substances that reduce soil acidity. The nitrogen in shrimp shell powder, humic acid and urea makes it have a suitable C / N ratio, which can reduce the fixation of soil nitrogen by microorganisms. The biochar-based amendment not only contains abundant functional groups and chitin, but also has a strong adsorption capacity, which can effectively reduce the possible heavy metal risk in fermented medicinal residues. The carboxymethyl cellulose sodium, xanthan gum, β-glucan and other components added to the biochar-based amendment pre-mix can improve the cohesion of soil particles. The complex of modified starch and acrylamide polymer also increases soil water retention and stability, which is conducive to improving the soil's water and fertilizer retention capacity and the content of water-stable aggregates. It can improve crop productivity by improving soil structure.

[0036] (4) Rapid alternation of wet and dry conditions can promote soil mineralization and soil aggregate formation. By planting European rapeseed, (sporadic) chicory, and wild pea in sequence, these three crops exhibit strong acidity adaptability and stress resistance, tolerance to poor soil, and strong root penetration. They grow well in newly reclaimed land, are easy to manage, and their well-developed root systems in deep soil can further disrupt the large soil structure. Root exudates can also promote the formation of soil aggregates. For example, sporadic chicory grows faster than common ryegrass and other herbaceous plants. By rotating it with the other two types of high-biomass plants, it provides a large amount of nutrients and organic matter to the poor soil, accelerates soil maturation, and improves soil fertility, thereby promoting the growth of tea seedling roots and nutrient absorption. In addition, sporadic chicory is rich in phenolic substances and other allelopathic substances, which can strongly inhibit or delay the germination of weed seeds and reduce the vitality of weed roots, effectively reducing weed damage in newly reclaimed tea gardens. Detailed Implementation

[0037] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0038] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0039] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0040] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0041] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0042] Unless otherwise specified, all raw materials used in the embodiments and comparative examples of this invention can be obtained through purchase.

[0043] The biochar-based modifiers used in the embodiments and comparative examples of this invention were prepared through the following steps:

[0044] 1) Dissolve 20g of starch in 300mL of 70℃ water, add 4g of potassium persulfate and stir to obtain solution A; at the same time, add 250g of potassium hydroxide, 80g of acrylamide and 0.2g of N,N-methylene-bisacrylamide sequentially to 300g of acrylic acid solution with a mass concentration of 0.45g / mL, stir and heat to 70℃ to obtain solution B; mix solutions A and B and stir; premix 50g of sodium carboxymethyl cellulose, 150g of xanthan gum and 200g of β-glucan, dissolve in 70℃ hot water, mix with solution A and B, stir until gelatinous, air dry and then dry by forced air drying, pulverize and pass through a 100-mesh sieve to obtain pre-made biochar-based soil conditioner.

[0045] 2) Weigh the following raw materials in parts by weight: 32 parts of peanut shell biochar with a particle size of 1-2mm, 20 parts of fermented plant-derived Chinese medicine residue powder, 12 parts of shrimp shell powder, 10 parts of humic acid, 12 parts of calcium-based bentonite, 8 parts of vermiculite, 4 parts of biochar-based soil conditioner pre-mixed material, and 2 parts of N-carboxymethyl acrylamide; mix the raw materials evenly.

[0046] 3) Spray urea solution onto the above-mentioned mixed raw materials and adjust the C / N ratio to 25 and the water content to 35%. Mix and granulate. Pass through a 4-6 mm sieve and freeze-dry or cold-air dry to a water content of 10% to obtain a biochar-based modifier, which is then packaged for later use.

[0047] The raw material used in the preparation of the biochar-based modifier in this invention—fermented plant-derived medicinal herb residue powder—is prepared through the following steps:

[0048] 1) The raw material of plant-derived Chinese herbal medicine residue consists of one or more of the following Chinese herbal medicines: Astragalus membranaceus, Artemisia argyi, Panax notoginseng, Forsythia suspensa, Taraxacum mongolicum, Atractylodes macrocephala, Bupleurum chinense, Pinellia ternata, Gastrodia elata, Cinnamomum cassia, Isatis indigotica, Rehmannia glutinosa, Anemarrhena asphodeloides, etc. The decocted herbal medicine residue is centrifuged to adjust the moisture content to 55-65%, and then pulverized to a length or diameter of 0.5-1 cm.

[0049] 2) Add urea to adjust the C / N ratio to 25-30, and then inoculate with a mixed inoculum of phosphate-solubilizing bacteria, thermophilic cellulose-degrading bacteria, Streptomyces flavus, Trichoderma, Bacillus subtilis, and Bacillus amyloliquefaciens. The inoculation amount is 0.5-1% of the total material.

[0050] 3) Place it in a fermentation tank for aerobic fermentation, turning it over according to temperature changes during the process. The fermentation time is 45-50 days.

[0051] 5) Dehydrate and dry to a moisture content of 10-15%, pulverize, and pass through a 60-80 mesh sieve. The raw material composition of the fermented plant-derived medicinal residue powder used in the specific embodiments and comparative examples to prepare the biochar-based modifier is: decoction and centrifugation-dehydrated residues of Astragalus membranaceus, Artemisia argyi, and Taraxacum mongolicum in a mass ratio of 1:1:1.

[0052] The embodiments and comparative examples of this invention were conducted on a plot of land awaiting reclamation within the Xieyu Datangmo Ecological Tea Garden Base in Huizhou District, Huangshan City. The soil pH value of the 0-30cm depth in this plot was 4.22, and the bulk density was 1.49 g / cm³. 3 The soil sand:silt:clay content was 37.51:29.51:32.97, and the soil texture was clay loam.

[0053] The oilseed cake used in the embodiments and comparative examples of this invention is a by-product of roasted rapeseed oil extraction, purchased from Shanghai Senong Environmental Protection Technology Co., Ltd., with N, P2O5 and K2O contents of 4.58%, 2.35% and 1.26%, respectively; the compound fertilizer used in the embodiments of this invention is purchased from Sinochem Shandong Fertilizer Co., Ltd., with N, P2O5 and K2O contents of 15%, 15% and 15%, respectively.

[0054] This invention, as described in the embodiments and comparative examples, involves the conventional planting of one-year-old short-cutting propagated tea seedlings. Specifically, double-row, double-plant planting is adopted, with the double rows of tea bushes arranged alternately, a wide row spacing of 1.5m, a narrow row spacing of 30cm, and a bush spacing of 33cm. Before planting, planting trenches are dug 35cm deep and 50cm wide; tea seedlings with uniform growth are selected and planted in the trenches according to the row and bush spacing requirements, and the soil is compacted to a height of 10cm from the ground; water is applied to settle the roots, and after the water has completely seeped in, the soil is compacted again to a height of 5cm from the ground; after planting, the tea seedlings are uniformly pruned to a height of 20cm. The number of tea trees planted is recorded for survival rate statistics. In early March of the following year, the tea trees are pruned to a height of 30cm from the ground, and after pruning, urea at a height of 1kgN / mu is applied in trenches on both sides of the wide rows; in April, when there are many weeds, manual weeding is used in the narrow rows, and shallow hoeing is used in the wide rows.

[0055] Example 1

[0056] (1) Before the grass seeds mature in September, clear away weeds, stones, debris, etc., collect the top 20cm of soil, add lime according to the goal of adjusting the soil pH to 5.5, pile it around the tea garden to be cultivated, cover it with film for sterilization and weed control for 25 days.

[0057] (2) After removing the topsoil, the soil is tilled to a depth of 60cm, and large roots, stones and other debris are removed. Then, drainage ditches are dug around the tea garden to be cultivated and inside the tea garden. Soil samples from the 0-40cm soil layer are collected by multi-point sampling method and the soil pH value is measured to be 4.2.

[0058] (3) Based on the measured soil acid buffer curve, calculate the amount of biochar-based amendment required to adjust the soil pH to 5.5; spread the biochar-based amendment evenly on the soil surface and plow to 40cm; irrigate the soil to make the soil moisture content reach 70% of the field capacity, cover with a film to maintain soil moisture for 1 week, uncover the film to dry the soil, and plow once during this period to promote soil drying; repeat this cycle of wet and dry for 4 times.

[0059] (4) Spread the topsoil evenly on the ground, then apply 200 kg / mu of biochar-based soil conditioner and till it to a depth of 60 cm.

[0060] (5) European rapeseed was sown in early November before winter, and the above-ground parts of the rapeseed plants were broken up and turned into the soil in March; then, chicory was sown and the above-ground parts were broken up and turned into the soil in early September after the growth period ended; wild peas were sown in early September, and the above-ground parts of the wild peas were broken up in early November, and 3000 kg / hm of cake fertilizer was applied. 2 Compound fertilizer 750kg / hm 2 As base fertilizer, till the soil to a depth of 40cm.

[0061] (6) Dig planting trenches and plant early cuttings of Shucha in the conventional way.

[0062] Comparative Example 1:

[0063] (1) In November, ditches will be dug and laid out for the tea garden to be built; all tree roots, miscellaneous trees, stones and other debris within the scope of the tea garden to be built will be cleared and mechanically reclaimed to a depth of 60cm.

[0064] (2) Utilize freeze-thaw cycles and sun exposure to promote soil weathering;

[0065] (3) Reclaim the land before planting tea trees in November of the following year. Before reclamation, apply lime to adjust the soil pH to 5.5. Remove weeds, rocks, etc. during land preparation. Apply 3000 kg / hm of cake fertilizer. 2 Compound fertilizer 750kg / hm 2 As base fertilizer, dig planting trenches and plant early cuttings of Shucha tea in the conventional way.

[0066] Comparative Example 2

[0067] The only difference from Example 1 is that the scattered chicory in step (5) is replaced with forage chicory, which belongs to the same genus of chicory in the family Asteraceae and has a similar growth period.

[0068] Comparative Example 3

[0069] The only difference from Example 1 is that the wild peas in step (5) are replaced with the arrowhead pea, which belongs to the same genus as the vetch and has no strict requirements on the sowing period.

[0070] One year after transplanting the tea trees, three 0-30cm soil profiles were dug at random locations in both the example and comparative examples. Ring samples and profile samples were collected, and the soil physical properties were determined. See Table 1 for details.

[0071] Table 1

[0072]

[0073] As can be seen from Table 1, the rapid improvement method for soil structure in acidic clay tea gardens using the present invention significantly improves soil porosity, field water holding capacity, silt content, and aggregate content with a particle size of 0.25-2mm compared to Comparative Example 1 (where subsoil and topsoil are directly tilled and mixed). The bulk density and compaction are lower than those of Comparative Example 1. The present invention has a better soil structure improvement effect.

[0074] Meanwhile, using a 5-point sampling method, soil profiles from 0 to 30 cm were randomly collected in Example 1 and Comparative Examples 1-3, and their physicochemical properties were measured. See Table 2 for details.

[0075] Table 2

[0076] pH value 5.46 5.01 5.42 5.39 Organic matter (g / kg) 28.14 17.82 27.65 26.98 Total nitrogen (g / kg) 1.95 1.10 1.84 1.75 Total phosphorus (g / kg) 0.76 0.67 0.82 0.74 Total potassium (g / kg) 23.80 17.95 21.47 24.02 Available nitrogen (mg / kg) 200.5 138.6 179.63 187.45 Available phosphorus (mg / kg) 13.84 7.18 14.72 12.96 Available potassium (mg / kg) 113.07 44.45 100.45 98.33

[0077] As shown in Table 2, compared with Comparative Example 1, the soil pH in Example 1 remained at a high level, and the contents of soil organic matter, total nitrogen, available nitrogen, available phosphorus and available potassium increased significantly. It can be seen that the rapid soil structure improvement method of the present invention can greatly improve the soil nutrient content and has a good acidity improvement effect.

[0078] In addition, one year after transplanting the tea trees in Examples 1 and 1-3, the survival rate of the tea seedlings in Examples 1 and 1-3 was investigated. The survival rate was the percentage of surviving plants (surviving above-ground branches) out of the total number of transplanted plants. Ten tea seedlings were randomly selected from the tea gardens of Examples 1 and 1-3, and the plant height, tree width, number of primary branches, and average length of the five longest new shoots were measured. Root distribution was observed by digging cross-sections. The results are shown in Table 3.

[0079] Table 3

[0080] Survival rate (%) 96.5 88.6 95.1 94.0 Plant height (cm) 56.6 33.9 53.8 50.7 Tree width (cm) 29.9 21.6 26.7 27.5 Number of first-order branches 7.78 4.35 6.81 6.36 New shoot length (cm) 13.8 8.1 12.4 11.2 Root depth (cm) 42.2 30.5 36.9 38.0

[0081] Table 3 shows that, in Example 1, the survival rate reached 96.5% one year after transplanting using the rapid soil improvement method of the present invention, and the tea tree height reached 56.6 cm. Compared with Comparative Example 1, the number of branches and the average length of new shoots increased by 78% and 70%, respectively. Simultaneously, the rapid soil improvement method increased the root depth of the tea trees by 38%. This demonstrates that the rapid soil improvement method of the present invention can significantly promote the growth of both the above-ground and underground parts of young tea trees. The plant height, tree width, number of primary branches, average length of new shoots, and root depth of Example 1 were significantly better than those of Comparative Examples 2 and 3. This indicates that the crop rotation combination of wild peas with chicory and rapeseed is superior to other plant rotation combinations. This may be because wild peas, scattered chicory, and rapeseed have relatively deep root distribution, strong root penetration, rapid growth, and large biomass. After crop rotation, the above-ground parts and well-developed root systems are mixed into the soil, and the nutrients formed in the soil are more conducive to the growth of tea trees (Shucha Zao).

[0082] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for rapidly improving the soil structure of acidic clay tea gardens, characterized in that, Includes the following steps: Step 1: Collect the topsoil from 0-20cm in depth and adjust its pH to 5.0-5.5 by adding lime. Then, cover the topsoil with a thin film to sterilize and kill weeds, thus obtaining the treated topsoil. Step 2: Till the soil with the topsoil removed to a depth of 55-65cm, remove debris, and then test the soil pH value. Step 3: Based on the measured soil acid buffering curve, calculate the amount of biochar-based amendment required to adjust the soil pH to 5.0-5.5; evenly spread the biochar-based amendment on the soil surface and till it to a depth of 40-50cm; irrigate the soil to bring the soil moisture content to 70%-80% of field capacity, cover it with a film, maintain soil moisture for 1 week, uncover the film to allow the soil to dry, tilling it once during this period to promote soil drying; repeat this cycle of alternating wet and dry conditions 3-4 times. Step 4: Spread the topsoil treated in Step 1 evenly on the ground surface, apply biochar-based amendment at a rate of 200 kg / mu, and till to a depth of 55-65 cm. Step 5: Rotate rapeseed, chicory and wild pea in sequence. After the rapeseed and chicory have finished growing, break up the above-ground plants and turn them into the soil. After the wild peas have finished growing, break up the above-ground plants and apply cake fertilizer and compound fertilizer. Plow to a depth of 55-65cm. In step 1, the topsoil is collected before the grass seeds mature in September. Before collecting the topsoil, weeds, stones, and debris must be cleared away. The preparation method of the biochar-based modifier includes the following steps: 1) Dissolve starch and potassium persulfate in water to obtain solution A; add potassium hydroxide, acrylamide and N,N-methylene-bisacrylamide to acrylic acid solution, heat and stir to obtain solution B; mix solution A and solution B to obtain a mixed solution; dissolve sodium carboxymethyl cellulose, xanthan gum and β-glucan in hot water to obtain solution C; mix solution C with the mixed solution, stir until gelatinous, air dry and then dry, pulverize and pass through a 100-mesh sieve to obtain biochar-based soil conditioner pre-mixed material; 2) Mix peanut shell biochar, fermented plant-derived medicinal herb residue powder, shrimp shell powder, humic acid, calcium-based bentonite, vermiculite, the biochar-based soil conditioner pre-mixed material, and N-carboxymethyl acrylamide to obtain a mixture. 3) Spray urea solution into the mixture to adjust the C / N ratio to 20-25 and the moisture content to 30-40%, mix and granulate; sieve and dry to a moisture content of 10% to obtain the biochar-based modifier; In step 1), the mass ratio of starch to potassium persulfate is 5g:1g; the temperature of solution A is 70°C; the mass ratio of potassium hydroxide, acrylamide, N,N-methylenebisacrylamide, and acrylic acid solution is 250:80:0.2:300; the concentration of acrylic acid solution is 0.45g / mL; the temperature of solution B is 70°C; the mass ratio of sodium carboxymethyl cellulose, xanthan gum, and β-glucan is 1:3:4; and the temperature of hot water is 70°C. In step 2), the mass ratio of peanut shell biochar, fermented plant-derived medicinal residue powder, shrimp shell powder, humic acid, calcium-based bentonite, vermiculite, biochar-based soil conditioner pre-mixed material, and N-carboxymethyl acrylamide is 30-35:18-20:12-15:10-12:10-12:5-8:2-5:1-2.

2. The method for rapidly improving the soil structure of acidic clay tea gardens according to claim 1, characterized in that, In step 2, after removing debris, dig mutually perpendicular drainage ditches around the tea garden to be cultivated and inside the tea garden, and collect soil samples from the 0-40cm soil layer using the multi-point sampling method to test the soil pH value.

3. The method for rapidly improving the soil structure of acidic clay tea gardens according to claim 1, characterized in that, In step 5, European rapeseed is sown in early November before winter, and the above-ground parts of the rapeseed plants are broken up and incorporated into the soil in March. Chicory is then sown, and its above-ground parts are broken up and incorporated into the soil in early September after its growth period. Wild peas are sown in early September, and the above-ground parts of the wild pea plants are broken up in early November, with 3000 kg / hm² of cake fertilizer applied. 2 Compound fertilizer 750kg / hm 2 As base fertilizer, till the soil to a depth of 40-50cm.

4. The method for rapidly improving the soil structure of acidic clay tea gardens according to claim 1, characterized in that, Step 5, after tilling, also includes digging planting trenches and planting tea seedlings.

5. The method for rapidly improving the soil structure of acidic clay tea gardens according to claim 1, characterized in that, In step 3), the sieving specifically refers to passing the material through a 4-6 mm sieve; the drying refers to freeze drying or cold air drying.

6. A method for promoting the growth of the above-ground and underground parts of young tea trees, characterized in that, The method for rapidly improving the soil structure of acidic clay tea gardens as described in claim 1 is used to improve the soil for planting young tea trees.

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