Method for improving saline-alkaline soil using salvia miltiorrhiza combined with biochar

Abstract

A method for improving saline-alkaline soil using Salvia miltiorrhiza combined with biochar, comprising the following steps: S1. Soil preparation: applying harmless treatment organic fertilizer as a base fertilizer, evenly applying biochar according to a proportion, plowing and tilling the soil, and, according to planting density and topographical conditions, planning ridge spacing and ridge width of double high ridges; S2. Salvia miltiorrhiza planting: performing Salvia miltiorrhiza seedling transplantation using a seedling transplantation method and hole planting means, digging holes on ridge surfaces, trimming overly long parts of seedling roots, planting seedlings vertically, and covering with soil; S3. field management after transplanting: performing fertilization, weeding, and top dressing management. The present method for improving saline-alkaline soil using Salvia miltiorrhiza cultivation combined with biochar application reduces soil pH and total salt content, increases soil sucrose enzyme activity, increases soil alkaline phosphatase activity, and alters soil microbiome structure.

Description

A method for improving saline-alkali land using tanshinone-based biochar Technical Field

[0001] This invention relates to the field of saline-alkali soil remediation technology, specifically a method for improving saline-alkali land using tanshinone-based biochar. Background Technology

[0002] Saline-alkali land is a general term for saline soil, alkaline soil, and various types of saline-alkali soil. It is formed under the combined effects of various natural environmental factors such as climate, geographical environment, and unreasonable irrigation, as well as human activities.

[0003] Because of the high salt content in saline-alkali soils, plants face ion stress, osmotic stress, and oxidative stress, which inhibits photosynthesis and hinders the transport of nutrients, thus limiting plant yield. At the same time, it also has a serious impact on soil structure, soil nutrients, and the stability of microbial communities. Therefore, soil salinization has always been regarded as one of the main forms of land degradation. The existing area of ​​saline-alkali land is about 99.13 million hectares, which has huge resource potential.

[0004] The disadvantages of physical remediation methods, which typically include leaching, topsoil replacement, soil replacement, and deep tillage, include: High resource consumption: Leaching requires large amounts of water for irrigation to flush away soil salts, which is difficult to implement in water-scarce areas and may lead to water waste and secondary pollution (e.g., improper wastewater discharge); Topsoil replacement requires large amounts of imported soil to replace saline-alkali soil, increasing transportation costs and potentially damaging soil structure in other areas, causing new environmental problems; Large engineering workload: Deep tillage, while improving soil structure, involves a large amount of engineering work, requiring significant investment of manpower and machinery, resulting in high costs; Limited effectiveness: Physical remediation methods often only temporarily alleviate salinization and cannot fundamentally address the causes of soil salinization, such as high groundwater levels and poor drainage; Environmental impact: During implementation, these methods may have certain impacts on the surrounding environment, such as… Chemical remediation methods, which address issues such as dust pollution and soil erosion, have several drawbacks. These methods primarily involve adding chemicals to the soil to react with pollutants, thereby reducing their biotoxicity and effectiveness. The main disadvantages include: secondary pollution risk: the chemicals used in chemical remediation may cause secondary pollution to the soil ecosystem, affecting the diversity and activity of soil microorganisms and thus impacting soil health; high cost: chemical remediation typically requires large quantities of expensive chemicals, increasing remediation costs; technical complexity: chemical remediation requires highly skilled operators with precise control over the dosage and reaction conditions; otherwise, it may cause even greater damage to the soil; and uncertain long-term effects: chemical remediation is not a permanent solution; over time, some chemicals may gradually lose their effectiveness, leading to the re-release of pollutants into the environment.

[0005] Therefore, the restoration and improvement of saline-alkali land has become a hot research topic, including the use of agricultural measures, physical methods, chemical methods and phytoremediation. Among them, agricultural measures require facilities and labor costs, while chemical methods may have problems such as chemical residues causing secondary pollution. The cultivation of medicinal plants can change the physiological characteristics of saline-alkali soil. Summary of the Invention

[0006] The purpose of this invention is to provide a method for improving saline-alkali land using a combination of Salvia miltiorrhiza and biochar. This method, through the application of biochar by planting Salvia miltiorrhiza, reduces soil pH from 8.31 to 7.92 and total salt content from 6.50 g·kg⁻¹. -1 Reduced to 5.78 g·kg -1The pH and total salt content decreased by 4.92% and 12.11%, respectively. The method of using danshen cultivation and biochar compounding to improve saline-alkali land reduced the soil sucrase activity from 11.27 mg / g. -1 24h -1 Increased to 17.59 mg / g -1 24h -1 Enzyme activity increased by 56.08%, and soil alkaline phosphatase activity increased from 3.24 μmol·g⁻¹. -1 24h -1 Increased to 5.83 μmol·g -1 24h -1 Enzyme activity increased by 79.94%. The method of applying biochar to improve saline-alkali land by planting Salvia miltiorrhiza caused changes in the microbial community structure in the soil. Two new genera, Canariomyces and Peziza, were added to the fungal community. Among the bacterial community, Sphingomonas had the largest increase in abundance, at 27.78%.

[0007] To achieve the above effects, the present invention provides the following technical solution: a method for improving saline-alkali land with tanshinone-based biochar, comprising the following steps:

[0008] S1. Prepare the land by selecting a flat, deep, and well-drained plot of land for planting Salvia miltiorrhiza. Sandy loam is the preferred soil type, which is conducive to the growth of Salvia miltiorrhiza roots. Salvia miltiorrhiza can be rotated with crops such as corn, wheat, coix seed, beans, castor beans, or non-root medicinal herbs to inhibit the accumulation of soil pathogens. Apply harmless organic fertilizer as base fertilizer and apply biochar evenly in proportion. Rotary tillage and turn the soil. Plan the ridge spacing. Based on the planting density and terrain conditions, plan the ridge spacing and ridge width for double-high ridges. The ridge width is 50-70cm, and the ridge spacing is determined according to actual needs. Ridging operation. Use agricultural machinery or manual methods to ridge according to the planned ridge spacing and ridge width, ensuring that the ridge surface is flat, the soil is finely broken, and the ridge height reaches more than 20cm to meet the requirements of double-high ridges. After ridgeding, tidy up the ridge surface to ensure that the ridge surface is flat and free of pits, which is convenient for subsequent planting and management.

[0009] S2. To plant Salvia miltiorrhiza, select healthy, robust, bright red, and disease-free seedlings. Transplant the seedlings using the hole planting method. Make holes on the ridge, trim the excessively long parts of the seedling roots, and plant them vertically. Cover with soil. For the second year, transplant the Salvia miltiorrhiza seedlings by planting them upright in the furrow or hole with the rhizome facing upwards. Cover with soil, compact it, and leave the heart bud slightly exposed.

[0010] S3. Field management after transplanting, including fertilization, weeding, and topdressing. Salvia miltiorrhiza needs sufficient water to grow. Watering should be done in a timely manner according to soil moisture and weather conditions to keep the soil moist. However, drainage ditches should be cleared before the rainy season to prevent waterlogging. Except for seed-saving plots, flower buds should be removed from plants in other planting areas in a timely manner to promote root growth and development. Bud removal should be done after 9 am and should not be done when there is dew. Topdressing should be applied during the flowering period and root swelling period of Salvia miltiorrhiza in the same year.

[0011] S4. Harvest the above-ground parts of Salvia miltiorrhiza after they have withered, and collect soil samples for relevant evaluation index determination.

[0012] Furthermore, the procedure includes the following steps: according to the operation steps in S1, the land preparation is carried out in early March, and the amount of harmlessly treated organic fertilizer used is 1500-2000 kg·hm². 2 The mixing ratio of the base fertilizer to biochar is 19:1.

[0013] Furthermore, the following steps are included: according to the operation steps in S1, the rotary tillage depth is about 30cm, after digging the trench, ridges are made with a ridge width of 60cm, a trench width of 20cm, and a row spacing of 25-30cm to increase soil permeability, while removing weeds and stones.

[0014] Furthermore, the procedure includes the following steps: according to the operation steps in S2, the planting time of the Salvia miltiorrhiza is controlled in mid-March, and the standard for robustness is ≥0.4cm at the base of the stem.

[0015] Furthermore, the procedure includes the following steps: according to the operation steps in S2, holes are made on the ridge surface, with a depth of 10cm.

[0016] Furthermore, the procedure includes the following steps: according to the operation steps in S2, the number of Salvia miltiorrhiza seedlings transplanted is 8,000-10,000 per mu.

[0017] Furthermore, the following steps are included: According to the operation steps in S3, during the root enlargement period of the Salvia miltiorrhiza, that is, from mid-August to early September, the fertilizer selection during the root enlargement period should be topdressing with phosphorus and potassium fertilizer.

[0018] Furthermore, the procedure includes the following steps: according to the operating steps in S3, 20-30 kg / mu of compound fertilizer is applied as topdressing during the flowering period of the Salvia miltiorrhiza.

[0019] Furthermore, the procedure includes the following steps: according to the operation steps in S4, the above-ground parts of the Salvia miltiorrhiza are harvested in early November after they wither.

[0020] Furthermore, the process includes the following steps: according to the operation steps in S4, the soil is evaluated for relevant indicators including pH, total salinity, soil sucrase, and soil alkaline phosphatase.

[0021] This invention provides a method for improving saline-alkali land using tanshinone-based biochar, comprising the following:

[0022] Beneficial effects:

[0023] (1) The method of using salvia miltiorrhiza cultivation and biochar compounding to improve saline-alkali land reduced the soil pH from 8.31 to 7.92 and the total salt content from 6.50 g·kg⁻¹. -1 Reduced to 5.78 g·kg -1 The pH and total salt content decreased by 4.92% and 12.11%, respectively.

[0024] (2) The method of using salvia miltiorrhiza planting and applying biochar to improve saline-alkali land reduced the soil sucrase activity from 11.27 mg / g. -1 24h -1 Increased to 17.59 mg / g -1 24h -1 Enzyme activity increased by 56.08%, and soil alkaline phosphatase activity increased from 3.24 μmol·g⁻¹. -1 24h -1 Increased to 5.83 μmol·g -1 24h -1 Enzyme activity increased by 79.94%.

[0025] (3) The method of applying biochar to improve saline-alkali land by planting Salvia miltiorrhiza caused changes in the microbial community structure in the soil. Two new genera, Canariomyces and Peziza, were added to the fungal community. The abundance of Sphingomonas in the bacterial community increased the most, by 27.78%. Attached Figure Description

[0026] Figure 1 is a schematic diagram of the process of a method for improving saline-alkali land with tanshinone compound biochar according to the present invention.

[0027] Figure 2 is a schematic diagram of the relative abundance of the top 10 species of bacteria and fungi at the genus level in a microbial community structure of saline-alkali land improved by planting Salvia miltiorrhiza and applying biochar. Detailed Implementation

[0028] 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.

[0029] Example 1

[0030] Please refer to Figures 1-2. A method for improving saline-alkali land using tanshinone-based biochar includes the following steps: S1. Land preparation is carried out in early March, and 1500-2000 kg·hm² of harmlessly treated organic fertilizer is applied. -2Biochar will be applied evenly at a ratio of 5% as base fertilizer. The soil will be rotary tilled and turned over. The ridge spacing will be planned according to planting density and terrain conditions. The ridge width will be 50-70cm, and the ridge spacing will be determined based on actual needs. Ridging will be carried out using agricultural machinery or manually, according to the planned ridge spacing and width, ensuring a flat ridge surface, fine soil, and a ridge height of at least 20cm to meet the requirements of double-high ridges. After ridge formation, the ridge surface will be tidied to ensure it is flat and free of pits, facilitating subsequent planting and management. The advantages of double-high ridge planting for Salvia miltiorrhiza are mainly reflected in the following aspects: Increased soil temperature: The design of double-high ridges can increase soil temperature... Increasing soil surface area allows for greater absorption of solar radiation, thus raising soil temperature, especially in early spring and late autumn. Double-ridged soil structures effectively maintain soil temperature, providing a suitable environment for Salvia miltiorrhiza growth. They also offer moisture retention, reducing evaporation and loss, ensuring a stable water supply for Salvia miltiorrhiza. Furthermore, the relatively loose soil structure of double-ridged soil promotes air circulation and aeration, aiding root respiration and promoting root growth and development. Finally, the double-ridged design allows rainwater to drain quickly between the ridges, reducing waterlogging and minimizing root diseases in Salvia miltiorrhiza. Risk reduction, especially important in rainy or low-lying areas, increases root growth: Double-ridge planting provides more space for the roots of Salvia miltiorrhiza to grow, which is conducive to the extension and development of the roots, thereby increasing the number and weight of roots and improving the yield of Salvia miltiorrhiza. Improved light conditions: The double-ridge planting method makes the light between Salvia miltiorrhiza plants more uniform, reduces shading between plants, and is conducive to photosynthesis and nutrient accumulation in the leaves, thus improving the quality of Salvia miltiorrhiza. Reduced humidity: The soil moisture in double-ridges is relatively low, which is not conducive to the breeding and reproduction of some moisture-loving pests and diseases, thereby reducing the occurrence of pests and diseases. Easier management: The double-ridge planting method makes field management more convenient, such as... Weeding, fertilizing, and watering can be carried out more efficiently, which is conducive to timely detection and prevention of pests and diseases and increases yield. As mentioned earlier, the double-ridge planting method can significantly increase the yield of Salvia miltiorrhiza, thereby increasing farmers' economic income and reducing costs. Although the double-ridge planting method may require more investment in the early stage (such as ridge-making machinery, labor, etc.), in the long run, its economic benefits are significant due to the reduction of pests and diseases and the increase in yield. The rotary tillage depth is about 30cm, and after digging trenches, ridges are made with a ridge width of 60cm, a trench width of 20cm, and a row spacing of 25-30cm. Salvia miltiorrhiza is planted in mid-S2 and mid-March, selecting strong and robust buds (stem base ≥0).4cm long, bright red, disease-free Salvia miltiorrhiza seedlings were selected and transplanted using a hole-planting method. Holes were dug on the raised bed, 10cm deep. Excessively long roots were trimmed before vertical planting. Soil was then added. Approximately 8000-10000 seedlings were transplanted per acre. After transplanting, field management included fertilization, weeding, and topdressing. Salvia miltiorrhiza requires ample water; watering should be done promptly according to soil moisture and weather conditions to keep the soil moist. However, drainage ditches should be cleared before the rainy season to prevent waterlogging. Additional fertilization was applied during the flowering and root enlargement stages of the same year. During the root enlargement period, from mid-August to early September, the fertilizer selection during this period should be topdressing with phosphorus and potassium fertilizers. During the flowering period of *Salvia miltiorrhiza*, apply compound fertilizer at 20-30 kg / mu. Harvest *Salvia miltiorrhiza* after the above-ground parts wither in early to mid-November, and collect soil samples for relevant evaluation index determination. The soil evaluation indexes include pH, total salt content, soil sucrase, and soil alkaline phosphatase. Using biochar compounding to improve saline-alkali soil during *Salvia miltiorrhiza* planting reduced soil pH from 8.31 to 7.92 and total salt content from 6.50 g·kg. -1 Reduced to 5.78 g·kg -1 The pH and total salt content decreased by 4.92% and 12.11%, respectively. The method of using danshen cultivation and biochar compounding to improve saline-alkali land reduced the soil sucrase activity from 11.27 mg / g. -1 24h -1 Increased to 17.59 mg / g -1 24h -1 Enzyme activity increased by 56.08%, and soil alkaline phosphatase activity increased from 3.24 μmol·g⁻¹. -1 24h -1 Increased to 5.83 μmol·g -1 24h -1 Enzyme activity increased by 79.94%. The method of applying biochar to improve saline-alkali land by planting Salvia miltiorrhiza caused changes in the microbial community structure in the soil. Two new genera, Canar iomyces and Peziza, were added to the fungal community. The abundance of Sphingomonas in the bacterial community increased the most, by 27.78%. In Figure 2, A: relative abundance of the top 10 species based on the genus level of bacterial ASV, and B: relative abundance of the top 10 species based on the genus level of fungal ASV.

[0031] Example 2

[0032] Please refer to Figure 1. A method for improving saline-alkali land using tanshinone-based biochar includes the following steps: S1. Land preparation is carried out in early March, and 1500-2000 kg·hm² of harmlessly treated organic fertilizer is applied. -2Biochar will be applied evenly at a ratio of 5% as base fertilizer. The soil will be rotary tilled and turned over. The ridge spacing will be planned according to planting density and terrain conditions, with a ridge width of 50-70cm and a ridge spacing determined based on actual needs. Ridging will be carried out using agricultural machinery or manually, according to the planned ridge spacing and width, ensuring a flat ridge surface, fine soil, and a ridge height of at least 20cm to meet the requirements of double-high ridges. After ridge formation, the ridge surface will be prepared to ensure it is flat and free of pits, facilitating subsequent planting and management. The rotary tillage depth will be approximately 30cm. After digging furrows, ridges will be formed with a ridge width of 60cm, a furrow width of 20cm, and a row spacing of 25-30cm. Next, holes will be dug on the ridge surface, 10cm deep, and soil will be piled up. Finally, after transplanting, fertilization and topdressing will be carried out. For field management, Salvia miltiorrhiza requires sufficient water for growth. Watering should be done in a timely manner according to soil moisture and weather conditions to keep the soil moist. However, drainage ditches should be cleared before the rainy season to prevent waterlogging. Fertilizer should be applied during the same period as the flowering and root enlargement periods of Salvia miltiorrhiza. During the root enlargement period of Salvia miltiorrhiza, which is from mid-August to early September, phosphorus and potassium fertilizers should be applied. During the flowering period of Salvia miltiorrhiza, compound fertilizer should be applied at 20-30 kg / mu. S4. For the Salvia miltiorrhiza of Example 1, after the above-ground parts of Salvia miltiorrhiza wither in early to mid-November, weeds should be completely harvested and disposed of. Weeds need to be completely harvested, including fallen leaves and underground rhizomes. Soil samples should be collected for relevant evaluation index testing, including pH, total salt content, soil sucrase, and soil alkaline phosphatase.

[0033] Example 3

[0034] Please refer to Figure 1. A method for improving saline-alkali land using tanshinone compound biochar includes the following steps: S1. In early March, land preparation is carried out by rotary tillage and turning over the soil. The ridge spacing is planned according to the planting density and terrain conditions. The ridge width is 50-70cm, and the ridge spacing is determined according to actual needs. Ridging is performed using agricultural machinery or manually, according to the planned ridge spacing and width, ensuring a flat ridge surface, fine soil, and a ridge height of at least 20cm to meet the requirements of double-high ridges. The ridge surface is then tidied up. After ridge formation... The ridge surface is prepared to ensure it is flat and free of pits, facilitating subsequent planting and management. The rotary tillage depth is about 30cm. After digging furrows, ridges are made with a ridge width of 60cm, a furrow width of 20cm, and a row spacing of 25-30cm. S2. In mid-March, holes are dug on the ridge surface with a depth of 10cm. S3. Weeding is carried out, and the number and growth of weed plants are recorded. S4. Soil samples are collected from early to mid-November for relevant evaluation index determination, including pH, total salt content, soil sucrase, and soil alkaline phosphatase.

[0035] In the above embodiments, soil samples were collected and relevant evaluation indicators were measured, resulting in the specific parameters shown in Table 1:

[0036] Table 1 - Changes in soil nutrient content after planting Salvia miltiorrhiza and applying biochar to improve saline-alkali land

[0037]

[0038] In summary, Example 2, compared to Example 1, lacked the specific transplanting and planting of *Salvia miltiorrhiza*. As a comparison, it confirmed the impact of fertilization, field management, and naturally growing weeds on soil indicators. The native weeds, due to fertilization and field management, had optimized growth conditions, which to some extent affected soil indicators. Example 3 differed from Example 1 in that it reduced the planting of *Salvia miltiorrhiza*, prohibited weed growth, and refrained from fertilization. However, it still performed the land preparation, rotary tillage, furrowing and ridging, and hole-making required for *Salvia miltiorrhiza* planting, serving as a comparison with the land preparation, rotary tillage, furrowing and ridging, and hole-making processes in Example 1. The effects of planting holes on soil parameters were investigated, and the number and growth quality of native weeds were recorded. The results showed that fertilization and the land preparation, rotary tillage, furrowing, and planting holes on the ridges all stimulated rapid weed growth. However, no significant optimization was observed in pH, total salt content, soil sucrase, and soil alkaline phosphatase levels. This suggests that the bioaccumulation of native weeds can slowly optimize soil parameters. Example 1 demonstrates that using biochar compounding with Salvia miltiorrhiza planting to improve saline-alkali land reduced soil pH from 8.31 to 7.92 and total salt content from 6.50 g·kg⁻¹. -1 Reduced to 5.78 g·kg -1 The pH and total salt content decreased by 4.92% and 12.11%, respectively. The method of using danshen cultivation and biochar compounding to improve saline-alkali land reduced the soil sucrase activity from 11.27 mg / g. -1 24h -1 Increased to 17.59 mg / g -1 24h -1 Enzyme activity increased by 56.08%, and soil alkaline phosphatase activity increased from 3.24 μmol·g⁻¹. -1 24h -1 Increased to 5.83 μmol·g -1 24h -1 Enzyme activity increased by 79.94%. The method of applying biochar to improve saline-alkali land by planting Salvia miltiorrhiza caused changes in the microbial community structure in the soil. Two new genera, Canariomyces and Peziza, were added to the fungal community. The abundance of Sphingomonas in the bacterial community increased the most, by 27.78%.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for improving saline-alkali land using tanshinone-based biochar, characterized in that, Includes the following steps: S1. Prepare the land by selecting a flat, deep, and well-drained plot of land for planting Salvia miltiorrhiza. Sandy loam is the preferred soil type, which is conducive to the growth of Salvia miltiorrhiza roots. Salvia miltiorrhiza can be rotated with crops such as corn, wheat, coix seed, beans, castor beans, or non-root medicinal herbs to inhibit the accumulation of soil pathogens. Apply harmless organic fertilizer as base fertilizer and apply biochar evenly in proportion. Rotary tillage and turn the soil. Plan the ridge spacing. Based on the planting density and terrain conditions, plan the ridge spacing and ridge width for double-high ridges. The ridge width is 50-70cm, and the ridge spacing is determined according to actual needs. Ridging operation. Use agricultural machinery or manual methods to ridge according to the planned ridge spacing and ridge width, ensuring that the ridge surface is flat, the soil is finely broken, and the ridge height reaches more than 20cm to meet the requirements of double-high ridges. After ridgeding, tidy up the ridge surface to ensure that the ridge surface is flat and free of pits, which is convenient for subsequent planting and management. S2. To plant Salvia miltiorrhiza, select healthy, robust, bright red, and disease-free seedlings. Transplant the seedlings using the hole planting method. Make holes on the ridge, trim the excessively long parts of the seedling roots, and plant them vertically. Cover with soil. For the second year, transplant the Salvia miltiorrhiza seedlings by planting them upright in the furrow or hole with the rhizome facing upwards. Cover with soil, compact it, and leave the heart bud slightly exposed. S3. Field management after transplanting, including fertilization, weeding, and topdressing. Salvia miltiorrhiza needs sufficient water to grow. Watering should be done in a timely manner according to soil moisture and weather conditions to keep the soil moist. However, drainage ditches should be cleared before the rainy season to prevent waterlogging. Except for seed-saving plots, flower buds should be removed from plants in other planting areas in a timely manner to promote root growth and development. Bud removal should be done after 9 am and should not be done when there is dew. Topdressing should be applied during the flowering period and root swelling period of Salvia miltiorrhiza in the same year. S4. Harvest the above-ground parts of Salvia miltiorrhiza after they have withered, and collect soil samples for relevant evaluation index determination.

2. The method for improving saline-alkali land with tanshinone-based biochar according to claim 1, characterized in that, The process includes the following steps: According to the operation steps in S1, the land preparation is carried out in early March, and the amount of harmlessly treated organic fertilizer used is 1500-2000 kg·hm². 2 The mixing ratio of the base fertilizer to biochar is 19:

1.

3. The method for improving saline-alkali land with tanshinone-based biochar according to claim 1, characterized in that, The process includes the following steps: According to the operation steps in S1, the rotary tillage depth is about 30cm, after digging the trench, ridges are formed with a ridge width of 60cm, a trench width of 20cm, and a row spacing of 25-30cm to increase soil permeability and remove weeds and stones at the same time.

4. The method for improving saline-alkali land with tanshinone-based biochar according to claim 1, characterized in that, Includes the following steps: According to the operating steps in S2, the planting time of Salvia miltiorrhiza is controlled in mid-March, and the standard for robustness is ≥0.4cm at the base of the stem.

5. The method for improving saline-alkali land with tanshinone-based biochar according to claim 1, characterized in that, The procedure includes the following steps: according to the operation steps in S2, holes are made on the ridge surface, with a depth of 10cm.

6. The method for improving saline-alkali land with tanshinone-based biochar according to claim 1, characterized in that, The procedure includes the following steps: according to the operation steps in S2, the number of Salvia miltiorrhiza seedlings transplanted is 8,000-10,000 per mu.

7. The method for improving saline-alkali land with tanshinone-based biochar according to claim 1, characterized in that, Includes the following steps: According to the operating steps in S3, during the root enlargement period of the Salvia miltiorrhiza, which is from mid-August to early September, the fertilizer selection during the root enlargement period should be topdressing with phosphorus and potassium fertilizer.

8. The method for improving saline-alkali land with tanshinone-based biochar according to claim 1, characterized in that, Includes the following steps: According to the operating steps in S3, 20-30 kg / mu of compound fertilizer should be applied as top dressing during the flowering period of Salvia miltiorrhiza.

9. The method for improving saline-alkali land with tanshinone-based biochar according to claim 1, characterized in that, Includes the following steps: According to the operating steps in S4, the harvesting time for the above-ground parts of Salvia miltiorrhiza after they wither is in early November.

10. A method for improving saline-alkali land using tanshinone-based biochar according to claim 1, characterized in that, Includes the following steps: According to the operating steps in S4, the soil is evaluated for relevant indicators including pH, total salinity, soil sucrase, and soil alkaline phosphatase.

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