Rapid ecological restoration method suitable for continuous cropping obstacles of valeriana officinalis in Karst yellow soil area

Abstract

The invention discloses a rapid ecological restoration method suitable for continuous cropping obstacles of valeriana officinalis in a karst yellow soil area, and belongs to the technical field of ecological cultivation of traditional Chinese medicinal materials and soil restoration. According to the method, a sequential remediation strategy of first disinfection and then reconstruction is adopted for composite obstacles such as acid, sticky, thin and thin soil and microbial unbalance after continuous cropping of valeriana officinalis in the karst yellow soil area. Firstly, quick lime or metham is selected to disinfect soil, and the pathogen cardinal number is rapidly reduced; then, an ecological reconstruction composite material formed by compounding 20-30 parts of biochar, 40-50 parts of organic fertilizer, 15-25 parts of leguminous green manure fresh body or dry powder and 5-10 parts of a specific functional microbial agent is immediately applied, and full fusion of the ecological reconstruction composite material and the soil is achieved through uniform mixing. According to the method, through organic combination of disinfection and multi-material synergistic remediation, soil acidification improvement, nutrient improvement and microbial community reconstruction are synchronously achieved, and systematic and rapid ecological remediation of continuous cropping obstacles is achieved. The method has high efficiency, ecological friendliness and regional pertinence, and a systematic solution is provided for sustainable production of the traditional Chinese medicinal materials in the karst ecologically fragile region.

Description

Technical Field

[0001] This invention relates to the field of ecological cultivation and soil remediation technology for Chinese medicinal herbs, and more specifically, to a rapid ecological restoration method for the continuous cropping obstacle of broadleaf valerian in karst yellow soil areas. Background Technology

[0002] Continuous cropping obstacles in Chinese medicinal herbs are a key common problem restricting the sustainable development of the industry. The core issue lies in the imbalance of the soil micro-ecosystem, depletion of specific nutrients, accumulation of allelochemicals, and enrichment of soil-borne pathogens caused by long-term monoculture. (Valeriana latifolia) Valeriana officinalis L. var. latifolia As an important medicinal herb whose rhizomes are used in traditional Chinese medicine, *Miq.* faces particularly prominent problems of continuous cropping obstacles in its large-scale cultivation in the karst yellow soil region of Guizhou. The soil in this area is inherently fragile, characterized by acidity, stickiness, compaction, and poor soil quality. This, combined with the biological obstacles caused by continuous cropping, creates a complex "soil environment-microbial community" barrier that is extremely difficult to manage and directly leads to severely impaired growth and development of replanted plants, and a significant decline in root yield and quality.

[0003] Currently, the control of continuous cropping obstacles in medicinal plants mainly follows two technical approaches: one is soil disinfection, primarily using chemical methods, and the other is biological improvement, represented by microbial inoculation. However, both have significant limitations in addressing the complex "soil environment-microbial community" obstacle faced by *Valeriana latifolia* in karst yellow soil regions. While chemical methods (such as fumigants like dazomet) can rapidly kill soil-borne pathogens, their broad-spectrum action severely damages beneficial soil microbial communities while eliminating harmful organisms. Furthermore, they fail to improve already deteriorated soil physicochemical properties, resulting in unsustainable effects, and repeated use can exacerbate soil ecological function decline. Biological improvement methods (such as applying specific compound microbial agents) aim to regulate the rhizosphere environment through exogenous beneficial bacteria. However, in continuously cropped yellow soils with high pathogen populations and severely deteriorated physicochemical properties, the colonization success rate of beneficial bacteria is low, making it difficult to exert a stable effect. Furthermore, conventional measures such as applying quicklime to adjust soil acidity or increasing organic fertilizer application often only alleviate soil acidification or nutrient deficiency problems individually, failing to form a synergistic technological chain of "pathogen eradication—soil improvement—ecological reconstruction." It is particularly noteworthy that existing technical solutions are mostly designed for bulk medicinal herbs such as ginseng and Panax notoginseng, lacking consideration for the adaptability of Valerian and its specific habitat—karst yellow soil. Therefore, the stability and sustainability of remediation effects in localized applications are generally insufficient. Overall, existing technologies mostly rely on single mechanisms of action, failing to construct a sequential remediation logic of "first eliminating biological inhibitory factors, then systematically rebuilding soil health functions." When dealing with complex obstacles involving multiple factors, the various measures often restrict each other, making it difficult to achieve sustained synergistic effects.

[0004] In summary, existing technologies either focus on rapid eradication at the expense of soil ecological health, or focus on localized improvement but struggle to quickly establish a stable and healthy micro-ecosystem in harsh, continuously cropped soils. Therefore, the industry urgently needs an innovative targeted remediation strategy to address the unique "complex obstacles" of broadleaf valerian in karst yellow soil regions. This invention aims to overcome the bottlenecks of existing technologies and provide an integrated method that can synergistically achieve "rapid and efficient eradication" and "systemic ecological reconstruction." The core of this method lies in the orderly combination and synergistic intervention of multiple materials and multiple targets, which not only efficiently eradicates pathogens but also simultaneously achieves rapid correction of soil physicochemical properties and the reconstruction of healthy, stable soil microbial communities. This provides a complete, efficient, and ecologically sustainable solution for overcoming the continuous cropping obstacles of this specific medicinal herb in specific production areas. Summary of the Invention

[0005] To address the aforementioned deficiencies in existing technologies, this invention aims to provide a rapid ecological restoration method specifically for the continuous cropping obstacles of broadleaf valerian in karst yellow soil regions. The core technical problem this method needs to solve is: how to overcome the limitations of existing single-technology measures, such as simple chemical disinfection or simple biological improvement, and simultaneously and efficiently achieve rapid elimination of highly pathogen-laden soils in the unique habitat of the Guizhou karst yellow soil region, systematic improvement of deteriorating physicochemical properties such as acidity, stickiness, compaction, and poor soil quality, and reconstruction of stable, benign soil microbial communities, thereby completely breaking down the complex barrier of "soil environment-microbial community" and restoring soil health and productivity.

[0006] To solve the above-mentioned technical problems, the present invention provides a rapid ecological restoration method for the continuous cropping obstacle of broadleaf valerian in karst yellow soil areas. The method is characterized by the following steps: (1) Soil targeted disinfection and microenvironment pretreatment: This step aims to create a low pathogen pressure and suitable physicochemical conditions for subsequent ecological reconstruction. Soil disinfectant is applied to the continuous cropping soil after the previous crop is harvested, preferably quicklime or chlorpyrifos, and then the soil is covered with film for sealing. (2) Multi-dimensional soil ecological reconstruction: After the film is removed and the soil is aerated in step (1), an ecological reconstruction composite material is immediately applied to the soil and rotary tilled and mixed. The composite material is composed of the following components in the following weight ratio: 20-30 parts biochar, 40-50 parts organic fertilizer, 15-25 parts fresh or dry leguminous green manure, and 5-10 parts specific functional microbial agents. (3) Ecological planting based on healthy soil: After completing the soil reconstruction in step (2), broadleaf valerian is transplanted or sown according to local conventional farming time and agronomic measures. Thanks to the fundamental restoration of soil health, the application of chemical fertilizers and pesticides can be significantly reduced during the subsequent growing season, with the main focus on water management and supplementation of necessary micronutrients.

[0007] Preferably, when using quicklime as a disinfectant, the application rate is 100-150 kg per acre. After application, it is essential to successively till the soil to a depth of 20-30 cm, irrigate until the soil's field water holding capacity reaches over 80%, and then immediately cover the soil with plastic film for 15-20 days. This series of coordinated operations promotes the full reaction between quicklime and water, creating and maintaining a long-lasting, evenly distributed, high-alkaline, high-temperature microenvironment within the soil's topsoil layer, thereby effectively and physicochemically killing soil-borne fungi, bacteria, nematodes, and weed seeds.

[0008] Preferably, when using Viagra as a disinfectant, the standard fumigation operation should be carried out according to the recommended dosage in its product instructions. After fumigation, the film should be removed and the gas should be fully dissipated until there is no irritating odor.

[0009] Preferably, biochar has a special porous structure that provides physical protection for the subsequent inoculation of microbial agents, ensuring their initial colonization in the soil; at the same time, it adsorbs potentially harmful substances and allelopathic autotoxins that may remain in the soil, and continuously regulates the soil pH, buffering the strong alkalinity of the preceding steps.

[0010] Preferably, fresh or dry organic fertilizer and leguminous green manure are used in the soil to provide a combination of fast-acting and slow-acting organic carbon sources and comprehensive mineral nutrients, rapidly activating soil microbial activity. In particular, the decomposition of green manure helps to further improve the soil's physical structure.

[0011] Preferably, the total number of effective viable bacteria in the specific functional microbial agent is not less than 2.0 × 10⁻⁶. 9 The CFU / g contains at least two of the following: Bacillus subtilis, Bacillus mucilaginosa, and Trichoderma. These bacteria respectively perform functions such as antibacterial activity, phosphorus and potassium solubilization, and parasitizing pathogens. They multiply rapidly with the support of biochar and organic nutrients, constructing a rhizosphere microecology dominated by beneficial bacteria.

[0012] Compared with existing patented technologies, the "disinfection-reconstruction-planting" sequential process proposed in this invention has a rigorous logical progression. The initial targeted disinfection clears the way for subsequent biological measures, while the immediate multi-material ecological reconstruction not only consolidates the disinfection effect but also rapidly rebuilds the soil's healthy function. This design overcomes the drawbacks of fragmented effects from single measures, achieving innovation and synergistic effects in the restoration logic.

[0013] Pot experiments have demonstrated that, after treatment with the method of this invention, compared with the untreated control soil, the biomass of the upper part and tubers of the subsequent broadleaf valerian crop can be increased several times, the soil pH and organic matter content can be significantly improved, the Shannon diversity index of the soil bacterial community can be significantly increased, the bacteria / fungus ratio (B / F Ratio) can be increased, and the soil microecological health can be significantly improved.

[0014] All technical parameters and material ratios in this solution are designed specifically for the obstacle characteristics of karst yellow soil and the physiological needs of broadleaf valerian, making it highly targeted. While ensuring remediation efficiency, it reduces the long-term dependence on chemical inputs for production by enhancing the soil's own biological and ecological functions, achieving a balance between ecological and economic benefits, and providing a reliable technical paradigm for the sustainable utilization of soil in medicinal herb producing areas.

[0015] Additional aspects and advantages of the invention will become apparent from the description which follows, or may be learned by practice of the invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and experimental data. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0017] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; and the materials and reagents used are commercially available unless otherwise specified. Example 1

[0018] Soil used for testing: collected from continuously cropped broadleaf valerian in Jiangkou County, Tongren City, Guizhou Province ( Valeriana officinalis L. var. latifolia Miq.) One year after the soil was cultivated (0-20 cm) of yellow soil. The basic physical and chemical properties of the soil were: pH value 5.88, organic matter content 37.42 g / kg, and available nitrogen, available phosphorus and available potassium contents 165.4 mg / kg, 13.61 mg / kg and 162.5 mg / kg, respectively.

[0019] Test plant: broadleaf valerian ( Valeriana officinalis L. var. latifolia (Miq.) Healthy seedlings, all of uniform age.

[0020] Repair materials: Microbial (42% aqueous solution, commercially available); biochar (made from corn stalks through pyrolysis at 500℃ under limited oxygen conditions, particle size 2-4 mm, pH 9.15); organic fertilizer (commercial organic fertilizer, fully decomposed, organic matter content ≥45%, moisture content ≤30%); compound microbial inoculant (commercially available product, total effective viable bacteria count ≥5.0×10⁻⁶). 9 CFU / g, containing Bacillus subtilis, Bacillus mucilaginosa, and Trichoderma harzianum; green manure (fresh Vicia sativa, harvested during peak flowering).

[0021] This embodiment sets up 5 treatments to systematically compare the effects of different repair strategies. All treatments used pots of uniform size, and each treatment was repeated 5 times. Details of each treatment design are shown in Table 1. Experimental Design

[0022] Processing group number Processing description Design Purpose CK Control: Soil subjected to continuous cropping without any remediation treatment. Assess the baseline level of continuous cropping obstacles T1 Disinfection + Organic Fertilizer: After disinfection, apply organic fertilizer separately (at a rate of 45g / kg). Verify the effectiveness of the "disinfection + traditional fertilization" model T2 Disinfection + Biochar: After disinfection, apply biochar alone (at a rate of 25g / kg). Verify the effectiveness of the "disinfection + physical modification" model T3 Disinfection + Microbial Agent: After disinfection, apply compound microbial agent alone (application rate 7.5g / kg). Verify the effectiveness of the "disinfection + biological inoculation" model T4 The invention involves applying a composite material of organic fertilizer, biochar, microbial agent, and green manure (in a ratio of 45:25:7.5:20) after disinfection of the plant. Verify the overall effectiveness of the "sequential collaborative repair" scheme of this invention. The specific implementation steps are as follows: (1) Soil targeted disinfection pretreatment All potted soil used in treatment groups T1-T4 was irrigated with Vibrio hydrochloride at the recommended dosage, immediately covered with plastic film and sealed tightly for 15 days of fumigation. After fumigation, the film was removed and the soil was turned over to allow for thorough aeration for 10 days until no irritating odor remained. The soil in the control group (CK) was not subjected to this disinfection treatment.

[0023] (2) Comparison of Differentiated Ecological Reconstruction After the disinfection pretreatment was completed, except for the CK group, each treatment group was given the corresponding materials according to the design plan. All materials were mixed with the soil by tilling to a depth of 15-20 cm.

[0024] (3) Planting and Management After completing the corresponding operations, all treatment groups (including the control group) were allowed to equilibrate for 5 days. Subsequently, three broadleaf valerian seedlings of uniform growth were transplanted into each pot and placed in a rainproof shed for routine watering management, without the application of chemical fertilizers. The planting cycle was 120 days.

[0025] (4) Soil and plant sample collection and analysis During the mature harvest period of valerian, the aboveground and underground parts were collected and their biomass was measured. Soil samples were collected from multiple locations. Some samples were stored in a -80℃ freezer for soil microbial analysis. Bacterial diversity was measured by amplifying the 16S rRNA gene fragment, while fungal diversity was measured by amplifying the ITS (intrinsic transcription spacer) gene fragment. Other samples were air-dried, sieved, bagged, and stored for the determination of soil physicochemical indicators.

[0026] A pot experiment was conducted to compare the present invention with a control group and various individual technologies. The relevant valerian growth indicators, soil nutrient and microbial community structure indicators are shown in Table 1. Table 1. Effects of different improvement measures on valerian growth and soil nutrients and microbial community structure during continuous cropping. deal with CK T1 T2 T3 This invention (T4) Fresh weight of above-ground parts / g 21.33±1.74d 85.49±2.89c 111.03±2.78b 76.88±1.09c 138.77±7.41a Fresh weight of tubers / g 25.18±2.06e 77.32±2.61c 88.97±2.23b 66.8±0.95d 128.56±6.55a pH 5.83±0.05c 6.48±0.19b 6.82±0.07a 6.43±0.06b 6.74±0.06a Organic matter content (g / kg) 38.42±0.44c 48.78±0.22b 62.10±0.50a 38.28±0.66c 58.37±1.51a Alkaline hydrolyzable nitrogen content (mg / kg) 155.97±3.67b 188.71±6.97a 160.84±6.93b 151.43±4.07b 184.73±7.44a Available phosphorus content (mg / kg) 13.22±0.33d 43.04±3.14a 32.72±1.30b 25.62±1.37c 44.35±2.17a Available potassium content (mg / kg) 162.62±3.25c 231.63±7.12b 275.25±10.19a 148.96±5.82c 285.34±11.15a Shannon index of bacteria 6.62±0.45c 8.26±0.20ab 8.34±0.12ab 7.93±0.48b 8.87±0.22a Shannon index of fungi 3.86±0.49a 2.80±0.54b 3.01±0.87b 3.76±0.20a 2.77±0.21b Bacteria / Fungus Ratio 1.72±0.12d 2.95±0.26ab 2.77±0.14b 2.11±0.13c 3.20±0.19a Note: Different lowercase letters after the data in the same row indicate the processing time. P The difference was statistically significant at levels <0.05.

[0027] As shown in Table 1, the treatment groups exhibited significant differences in plant growth, soil physicochemical properties, and microbial community structure. These differences were specifically reflected in the following four aspects: (1) The effect of promoting plant growth.

[0028] The present invention (T4) showed the most significant growth-promoting effect on broadleaf valerian. The T4 treatment exhibited the highest fresh weight of both the aboveground parts and tubers, reaching 138.77 g and 128.56 g respectively, significantly higher than all other treatments. Compared to the untreated control group (CK), the increases were 550.59% and 410.56% respectively, directly demonstrating the core role of the present invention in overcoming continuous cropping obstacles in valerian and increasing economic yield. Furthermore, the fresh weight of the aboveground parts and tubers in the T4 treatment was also significantly higher than that of the treatments containing only a single material (organic fertilizer T1, biochar T2, and microbial inoculant T3), indicating that the synergistic combination of organic fertilizer, biochar, inoculant, and green manure produced a growth-promoting effect far exceeding that of simply adding a single material.

[0029] (2) Effects on improving soil physical and chemical properties This invention (T4) can simultaneously and significantly improve the chemical fertility of continuously cropped yellow soils. Specifically, the T4 treatment significantly increased the soil pH from acidic (5.83) in the control (CK) treatment to near neutral (6.74), an effect comparable to that of biochar application alone (T2). Simultaneously, the soil organic matter content increased significantly by 51.93% compared to the CK treatment, reaching 58.37 g / kg, which is the highest level, comparable to the biochar treatment (T2), indicating that the combined application has a significant effect on increasing carbon and improving soil. In terms of the three readily available nutrients—nitrogen, phosphorus, and potassium—the T4 treatment was at the highest or second-highest level. In particular, the content of available phosphorus and readily available potassium in the T4 treatment was 3.36 times and 1.75 times that of the CK treatment, respectively, and significantly higher than most single treatments. This confirms that this invention, through a synergistic model of "organic fertilizer supply + biochar retention + microbial activation," comprehensively improves the soil nutrient pool and supply intensity.

[0030] (3) Effects on the reshaping of soil microbial community structure This invention (T4) successfully guided the microecology of continuously cropped soils towards a healthier and more stable state. The T4 treatment exhibited the highest bacterial Shannon diversity index (8.87), significantly higher than the control (6.62), indicating that this invention greatly enriched the species diversity and evenness of the bacterial community. Compared to the control, the T4 treatment significantly reduced the fungal Shannon diversity index (from 3.86 to 2.77). Combined with practical production analysis, this reduction reflects the inhibition of excessive proliferation of pathogenic or harmful fungi in continuously cropped soils, optimizing fungal community function. Furthermore, the T4 treatment had the highest bacteria / fungus ratio (3.20), significantly higher than the control (1.72) and other treatments. These indicators collectively demonstrate that after remediation with this invention, the soil microbial community shifted from a fungal-dominated type (prone to soil-borne diseases) to a healthier bacterial-dominated type, fundamentally enhancing the stability and disease suppression potential of the soil ecosystem.

[0031] To clearly demonstrate, the core improvement effects of this invention (T4) compared to any single measure (T1-T3) are summarized as follows: Table 2. Comparative Analysis of the Synergistic Technical Effects of the Invention Scheme and the Optimal Single Measure (T2) Evaluation Dimensions Best single measure (T2: disinfection + biochar) The present invention solution (T4: disinfection + combination materials) The superiority and synergistic features of this invention pH adjustment effect Optimal (6.82) Second best (6.74) While achieving near-top-tier acidity adjustment results, it also takes all other indicators into account. Carbon enrichment effect (organic matter) Optimal (62.10) Second best (58.37) While maintaining top-tier carbon emission performance, it also takes all other indicators into account. Phosphorus and potassium supply (available phosphorus / available potassium) Non-optimal Overall optimal (44.35 / 285.34) It makes up for the shortcomings of biochar application alone in nutrient supply. Microbial community (B / F ratio) Suboptimal (2.77) Overall optimal (3.20) The microecological structure of biochar application alone was significantly optimized. Plant growth (fresh weight of tubers) Second best (88.97) Overall optimal (128.56) Significantly amplified the growth-promoting effect of biochar application alone. In summary, the remediation effect of this invention is not simply the sum of the effects of individual technologies (T1-T3). For example, while the application of biochar alone (T2) can effectively adjust acidity and increase carbon, it has limited effect on improving alkaline nitrogen uptake; while the application of organic fertilizer alone (T1) can significantly increase phosphorus and potassium, it is insufficient in optimizing the microbial community structure. However, the technical solution (T4) of this invention, through the synergistic input of multiple materials after disinfection, achieves a quadruple positive effect of "promoting growth, adjusting acidity and alkalinity, supplementing nutrients, and optimizing the microbial community," systematically breaking through the continuous cropping and complex obstacles of broadleaf valerian in karst yellow soil areas. Its comprehensive effect has unexpected and significant advantages.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rapid ecological restoration method suitable for the continuous cropping obstacles of P. latifolium in karst yellow soil areas, characterized in that, The method comprises the following sequential steps: (1) Soil targeted killing and pretreatment: after the harvest of the previous crop of broadleaf valerian, a soil sterilizing agent is applied to the continuous cropping soil and a film mulching and sealing treatment is performed; (2) Multi-dimensional soil ecological reconstruction: after the completion of step (1), an ecological reconstruction composite material is applied to the soil and mixed; the ecological reconstruction composite material comprises biochar, organic fertilizer, legume green manure and specific functional microbial agent; (3) Planting: after the completion of step (2), the planting of broadleaf valerian is performed.

2. The method of rapid ecological restoration according to claim 1, characterized in that: In step (1), the soil sterilizing agent is selected from quicklime or metam sodium.

3. The method of rapid ecological restoration according to claim 2, characterized in that: When the soil sterilizing agent is quicklime, the application amount is 100-150 kg per mu, and after application, plowing, watering and film mulching and sealing for 15-20 days are sequentially performed.

4. The method of rapid ecological restoration according to claim 2, characterized in that: When the soil sterilizing agent is metam sodium, soil fumigation is performed according to the recommended dose of the product, and after fumigation, the film is removed and the gas is dispersed.

5. The method for rapid ecological restoration according to claim 1, characterized in that: In step (2), the ecological reconstruction composite material is prepared by proportioning the following components: biochar 20-30 parts, organic fertilizer 40-50 parts, legume green manure fresh body or dry powder 15-25 parts, and specific functional microbial agent 5-10 parts.

6. The method for rapid ecological restoration according to claim 1 or 5, characterized in that: The raw material of the biochar is corn straw or rice straw, the pyrolysis temperature is 500°C, and the particle size is 2-4 mm.

7. The method for rapid ecological restoration according to claim 1 or 5, characterized in that: The effective total number of viable bacteria of the specific functional microbial agent is not less than 2.0 x 10 9 CFU / g, and contains at least two of Bacillus subtilis, Paenibacillus mucilaginosus, and Trichoderma.

8. The method for rapid ecological restoration according to claim 1 or 5, characterized in that: The legume green manure is fresh body or dry powder of arrow-shaped pea or Chinese milk vetch.

9. The method of rapid ecological restoration according to claim 1, characterized in that: In step (2), the ecological reconstruction composite material is applied at one time after the disinfection treatment, the film is removed and the gas is dispersed, and is mixed with the soil by rotary plowing.

10. The method of rapid ecological restoration according to claim 1, characterized in that: The method is suitable for the repair of the continuous cropping obstacles of broadleaf valerian in the karst landform yellow soil region of Guizhou Province.