A soil conditioner, its preparation and use

Abstract

This invention provides a soil conditioner, its preparation method, and its application, belonging to the field of soil remediation technology. The soil conditioner, by mass percentage, comprises the following components: 95%–97% tobacco straw, 0.5%–2% *Ulva prolifera* polysaccharide, 0.1%–0.5% fucoidan oligosaccharide, and 1%–2.5% *Bacillus* powder. Through the synergistic effect of its components, the soil conditioner provided by this invention can effectively improve soil compaction in coastal saline soils, enrich soil microbial biodiversity, and simultaneously enhance the salt and drought resistance of plants growing in coastal saline soils, thereby promoting plant growth and development. Example results show that the soil conditioner provided by this invention can significantly increase the stem height and dry weight of plants in coastal saline soils, increase the number of lateral branches, and promote root elongation; simultaneously, the soil conditioner can effectively improve the microbial diversity in coastal saline soils.

Description

Technical Field

[0001] This invention belongs to the field of soil pollution remediation technology, specifically relating to a soil conditioner, its preparation method, and its application. Background Technology

[0002] The rapidly increasing global population continues to cause a shortage of arable land resources, making it urgent to increase arable land to ensure food security. Coastal saline soils are an important type of marginal land and are considered a potential reverse land resource to alleviate arable land shortages. Salinity is a major environmental factor limiting plant growth in coastal saline soils. Due to osmotic stress, plant growth is often negatively affected by soil salinity. Soil salinization also leads to nutrient imbalances, negatively impacting plant nutrient absorption and causing slowed or inhibited plant growth. Therefore, developing effective methods to mitigate the effects of salt stress on plants is of great significance for the effective utilization of coastal saline soils. Summary of the Invention

[0003] In view of the deficiencies in the prior art, the purpose of this invention is to provide a soil conditioner that can improve the growth of plants in coastal saline soil and promote plant growth.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] This invention provides a soil conditioner, comprising the following components by weight percentage:

[0006] The composition includes 95%–97% tobacco straw, 0.5%–2% Ulva prolifera polysaccharide, 0.1%–0.5% fucoidan, and 1%–2.5% Bacillus spore powder.

[0007] Preferably, the Bacillus includes one or more of Bacillus amyloliquefaciens, Bacillus subtilis, and Bacillus belye.

[0008] The total bacterial count of the Bacillus is ≥1×10⁻⁶. 10 CFU / g.

[0009] Preferably, the *Bacillus amyloliquefaciens* includes *Bacillus amyloliquefaciens* Cas02, whose preservation number is CGMCC NO.15514; the *Bacillus subtilis* includes *Bacillus subtilis* Tpb55, whose preservation number is CGMCC NO.2853; and the *Bacillus belyss* includes *Bacillus belyss* EM-1, whose preservation number is CGMCC NO.21131.

[0010] Preferably, the soil conditioner comprises the following components by weight percentage:

[0011] The composition includes 96.3% tobacco straw, 1.0% Ulva prolifera polysaccharide, 0.2% fucoidan oligosaccharide, and 2.5% Bacillus spore powder.

[0012] This invention provides a method for preparing the soil conditioner described in the above technical solution, comprising the following steps:

[0013] After the tobacco straw is crushed, it is mixed with seaweed polysaccharide, brown algae oligosaccharide and Bacillus powder to obtain a soil conditioner.

[0014] Preferably, the particle size of the crushed tobacco straw is <5cm.

[0015] The present invention also provides an application of the soil conditioner described in the above technical solution or the soil conditioner prepared by the preparation method described in the above technical solution in improving coastal saline soil.

[0016] The present invention also provides the application of the soil conditioner described in the above technical solution or the soil conditioner prepared by the preparation method described in the above technical solution in promoting plant growth in coastal saline soil.

[0017] The present invention also provides a method for using the soil conditioner described in the above-mentioned technical solution or the soil conditioner prepared by the preparation method described in the above-mentioned technical solution, comprising:

[0018] Soil conditioner is added to coastal saline soil at a ratio of 5% to 20% by weight.

[0019] The beneficial effects of this invention are:

[0020] This invention provides a soil conditioner comprising, by weight percentage: 95%–97% tobacco straw, 0.5%–2% *Ulva prolifera* polysaccharide, 0.1%–0.5% fucoidan oligosaccharide, and 1%–2.5% Bacillus spp. powder. The tobacco straw in this soil conditioner improves the chemical properties of the soil, providing nutrients; it also improves the physical properties of coastal saline soil, including soil aggregate structure, water retention, and looseness. The *Ulva prolifera* polysaccharide and fucoidan oligosaccharide enhance the salt and drought resistance of plants and promote the rhizosphere colonization of Bacillus spp., enabling plants to better resist adverse conditions. Through the synergistic effect of its components, this soil conditioner effectively improves soil compaction in coastal saline soil, enriches soil microbial biodiversity, enhances the salt and drought resistance of plants, and thus promotes plant growth and development. The results of the examples show that the soil conditioner provided by the present invention can significantly increase the stem height, number of lateral branches and dry weight of plants in coastal saline soil, and promote the elongation of plant roots; at the same time, the soil conditioner can effectively improve the diversity of microorganisms in coastal saline soil. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 Figure showing the effect of adding different types of straw to coastal saline soil on the growth of peanut seedlings;

[0023] Figure 2 The figure shows the effect of adding the soil conditioner of Example 2 to coastal saline soil on the growth of peanut seedlings.

[0024] Figure 3 The figure shows the effect of the soil conditioner of Example 2 on the microbial diversity in coastal saline soil. Detailed Implementation

[0025] This invention provides a soil conditioner, comprising the following components by weight percentage:

[0026] The composition includes 95%–97% tobacco straw, 0.5%–2% Ulva prolifera polysaccharide, 0.1%–0.5% fucoidan, and 1%–2.5% Bacillus spore powder.

[0027] The soil conditioner provided by this invention comprises 95%–97% tobacco straw by weight percentage, more preferably 96%–97%, and even more preferably 96.3%. The tobacco straw used in this invention preferably originates from tobacco fields in Jiaozhou region. The tobacco straw used in this invention is preferably fresh tobacco straw after harvesting tobacco leaves and then sun-dried. The sun-drying time is preferably 3 months. The sun-drying is preferably carried out under open-air conditions. The sun-drying is preferably carried out until the straw moisture content is below 10%. In this invention, the tobacco straw can improve soil aggregate structure, increase soil water retention and maintain soil looseness, thereby improving soil physical properties; the tobacco straw can also provide certain nutrients to the soil and improve its chemical properties. Simultaneously, compared to other crop straws, tobacco straw has a lower C / N ratio, releasing more nitrogen during degradation, which is beneficial for plant absorption; the higher degree of lignification in tobacco straw results in a slower degradation rate, allowing for the continuous release of organic carbon, which is beneficial for plant growth.

[0028] The soil conditioner provided by this invention comprises, by weight percentage, 0.5% to 2% *Ulva prolifera* polysaccharide, more preferably 0.8% to 1.5%, and more preferably 1.0%. In this invention, the *Ulva prolifera* polysaccharide significantly promotes the formation of Bacillus biofilm and facilitates the effective colonization of Bacillus strains in the crop rhizosphere. The *Ulva prolifera* polysaccharide described in this invention was purchased from Qingdao Haida Biotechnology Co., Ltd.

[0029] The soil conditioner provided by this invention comprises, by weight percentage, 0.1% to 0.5% fucoidan, more preferably 0.2% to 0.3%, and more preferably 0.2%. In this invention, the fucoidan can provide a carbon source for the growth of Bacillus and improve the motility of Bacillus. The fucoidan described in this invention was purchased from Qingdao Hehai Biotechnology Co., Ltd.

[0030] The soil conditioner provided by this invention comprises 1% to 2.5% Bacillus powder by weight percentage, more preferably 1.5% to 2.5%, even more preferably 2.0% to 2.5%, and more preferably 2.5%. In this invention, the Bacillus preferably includes one or more of Bacillus amyloliquefaciens, Bacillus subtilis, and Bacillus vesalivarius, more preferably Bacillus amyloliquefaciens. In this invention, the total viability of the Bacillus is preferably ≥1×10⁻⁶. 11 CFU / g, more preferably 1×10 11CFU / g. In this invention, if the Bacillus includes Bacillus amyloliquefaciens, Bacillus subtilis, and Bacillus belyss, the preferred mass ratio of the Bacillus amyloliquefaciens, Bacillus subtilis, and Bacillus belyss is 1:1:1. In this invention, if any two of the Bacillus amyloliquefaciens, Bacillus subtilis, and Bacillus belyss are present, the preferred mass ratio of the two strains is 1:1. In this invention, the Bacillus amyloliquefaciens preferably includes Bacillus amyloliquefaciens Cas02, which is the strain disclosed in Chinese Patent CN108624543A and was deposited on March 26, 2018, at the China General Microbiological Culture Collection Center (Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, China), with the bio-accession number CGMCC. NO. 15514; the preferred Bacillus subtilis strain includes Bacillus subtilis Tpb55, which was deposited on December 29, 2008, at the China General Microbiological Culture Collection Center (Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, China), with accession number CGMCC NO. 2853; the preferred Bacillus berleis strain includes Bacillus berleis EM-1, which was deposited on May 6, 2021, at the China General Microbiological Culture Collection Center (Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, China), with accession number CGMCC NO. 21131. In this invention, the Bacillus strain exhibits strong stress resistance and can promote plant growth.

[0031] This invention provides a method for preparing the soil conditioner described above, comprising the following steps:

[0032] After the tobacco straw is crushed, it is mixed with seaweed polysaccharide, brown algae oligosaccharide and Bacillus powder to obtain a soil conditioner.

[0033] This invention involves pulverizing tobacco stalks to obtain pulverized tobacco stalks. The pulverizing method is not particularly limited; any conventional pulverizing method in the art can be used. In this invention, the particle size of the pulverized tobacco stalks is preferably <5 cm, more preferably <2 cm.

[0034] After obtaining the pulverized straw, the present invention mixes the pulverized straw with *Ulva prolifera* polysaccharide, *Alginate* oligosaccharide, and *Bacillus* powder to obtain a soil conditioner. The present invention does not specifically limit the mixing method; conventional methods in the art can be used to mix the raw materials evenly.

[0035] This invention also provides the application of the soil conditioner described in the above-described technical solution or the soil conditioner prepared by the preparation method described in the above-described technical solution in improving coastal saline soil. In this invention, the salt content of the coastal saline soil is preferably 0.2% to 0.8%, more preferably 0.5%. The soil conditioner provided by this invention can significantly improve the diversity of soil microorganisms in coastal saline soil, making the coastal saline soil suitable for crop growth. The soil conditioner provided by this invention can alleviate soil compaction, improve the pH conditions of coastal saline soil, and increase the ammonia nitrogen content in the soil.

[0036] This invention also provides the application of the soil conditioner described in the above-described technical solution or the soil conditioner prepared by the preparation method described in the above-described technical solution in promoting plant growth in coastal saline soil. In this invention, the soil conditioner can significantly improve the growth of peanuts in coastal saline soil, significantly promote the elongation of the main stem, significantly increase the number of lateral branches during the growth process of peanuts, promote root elongation, and increase the dry weight of the plant.

[0037] The present invention also provides a method for using the soil conditioner described in the above-mentioned technical solution or the soil conditioner prepared by the preparation method described in the above-mentioned technical solution, comprising:

[0038] The soil conditioner is added to coastal saline soil at a mass percentage of 5% to 20%.

[0039] In this invention, the soil conditioner is added directly to the coastal saline soil during use; the amount of soil conditioner added is preferably 5% to 20% of the mass percentage of the coastal saline soil, more preferably 10%.

[0040] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0041] In the following examples, the physicochemical properties of the coastal saline soil are as follows: bulk density 1.31 g / cm³ 3 It has a porosity of 50%, electrical conductivity of 1.065 ds / m, pH value of 7.62, ammonium nitrogen of 11.82 mg / kg, nitrate nitrogen of 3.36 mg / kg, organic matter of 10.17 g / kg, available phosphorus of 9.39 mg / kg, and salt content of approximately 0.5%.

[0042] Example 1

[0043] Effects of different straw additions on peanut growth in coastal saline soil

[0044] Rice straw, corn straw, and tobacco straw were added to coastal saline soil with a salt content of approximately 0.5%.

[0045] Rice straw, corn stalks, and tobacco stalks were pulverized separately to obtain pulverized rice straw, pulverized corn stalks, and pulverized tobacco stalks.

[0046] Crushed rice straw, crushed corn stalks, and crushed tobacco stalks were added to the coastal saline soil at 10% of its weight, respectively, and mixed thoroughly. These were designated as the rice straw soil group, corn stalk soil group, and tobacco stalk soil group, respectively. A negative control group was set up without added straw. The rice straw soil group, corn stalk soil group, and tobacco stalk soil group were incubated for one month, with soil moisture maintained at approximately 60% during incubation. The negative control group soil was left to stand naturally for one month. Soil samples from each experimental group and the control group were obtained after incubation. Each experiment was conducted in eight parallel trials, meaning each experiment included eight potted plants.

[0047] After incubation, the physicochemical properties of the incubated soil (soil before peanut planting) were tested, and the test results are shown in Table 1.

[0048] After germination, peanut seeds were placed in rice straw soil, corn straw soil, and tobacco straw soil that had been incubated separately, and cultivated in a greenhouse (light conditions: 16h, 28℃; darkness conditions: 8h, 20℃; relative humidity 60%). Each plant was watered weekly with approximately 100mL of sterilized water.

[0049] After two months of cultivation, the growth of peanut seedlings is as follows: Figure 1 As shown. Figure 1 From left to right, the soil groups are: no straw added (negative control group); rice straw soil group; corn straw soil group; and tobacco straw soil group. The plant growth-agronomic traits of the different treatment groups in the coastal saline soil were statistically analyzed, and the results are shown in Table 2.

[0050] Table 1. Effects of adding different types of straw on the physicochemical properties of coastal saline soil.

[0051] Group pH <![CDATA[NH4 + -N]]> Soil bulk density Soil porosity CK 7.62±0.04a 11.82±1.69b 1.31±0.10a 50％b straw 7.60±0.04ab 9.98±3.01b 1.10±0.03b 58％a corn 7.48±0.03b 5.25±0.81b 1.05±0.05b 60％a tobacco 7.35±0.03c 48.01±6.61a 1.05±0.07b 60％a

[0052] Note: Different letters in the same column indicate significant differences.

[0053] Straw was applied to the soil and incubated for about one month. The soil's physicochemical properties were then tested. Table 1 shows that a higher soil bulk density corresponds to lower porosity, indicating greater soil compaction. The results in the table indicate that adding straw significantly improves soil compaction. However, different types of straw have different carbon-to-nitrogen ratios. Adding rice straw and corn straw reduced ammonium nitrogen in the soil, which is detrimental to crop growth. Only tobacco straw significantly increased ammonium nitrogen in the soil. Therefore, considering all factors, tobacco straw is the optimal choice.

[0054] Table 2 Effects of different types of straw addition on plant growth and agronomic traits in coastal saline soil

[0055] Group Plant height / cm Number of lateral branches / each chlorophyll Branch weight / g Root dry weight / g Total dry weight / g CK 9.31±0.50b 5.38±0.42b 46.32±4.53a 0.80±0.20c 0.20±0.07c 1.00±0.27c straw 8.17±1.88b 6.00±0.58b 28.78±0.41b 1.55±0.69bc 0.36±0.11bc 1.91±0.66bc corn 9.09±0.21b 6.67±0.33b 24.69±1.24b 2.59±0.33b 0.50±0.06ab 3.09±0.43b tobacco 12.12±0.31a 8.26±0.40a 44.59±1.20a 4.18±0.45a 0.69±0.08a 4.87±0.45a

[0056] Note: Different letters in the same column indicate significant differences.

[0057] Depend on Figure 1 As shown in Table 2, different types of straw have varying effects on improving coastal saline soil. Tobacco straw, corn straw, and rice straw were added to coastal saline soil for remediation, and the results showed that tobacco straw was the most effective. Tobacco straw has a lower C / N ratio than the other two types of straw, allowing it to release more nitrogen during degradation, which is beneficial for plant absorption. Furthermore, tobacco straw has a higher degree of lignification than the other two types of straw, resulting in a slower degradation rate and continuous release of organic carbon, which is beneficial for plant growth.

[0058] Example 2-1

[0059] A soil conditioner, by mass percentage, comprises: 96.3% tobacco straw, 1.0% *Ulva prolifera* polysaccharide, 0.2% *Alginate* oligosaccharide, and 2.5% *Bacillus* powder.

[0060] The composition of the Bacillus powder is: Bacillus amyloliquefaciens Cas02, with a bacterial activity of 1×10⁻⁶. 11 CFU / g.

[0061] The preparation method of the soil conditioner includes the following steps:

[0062] The tobacco stalks are crushed to a particle size of <2cm to obtain crushed tobacco stalks;

[0063] A soil conditioner is obtained by mixing pulverized tobacco straw with Ulva polysaccharide, brown algae oligosaccharide and Bacillus powder.

[0064] Example 2-2

[0065] A soil conditioner, by mass percentage, comprises: 97.0% tobacco straw, 1.5% *Ulva prolifera* polysaccharide, 0.5% fucoidan oligosaccharide, and 1.0% Bacillus cereus powder.

[0066] The Bacillus powder composition is: Bacillus amyloliquefaciens Cas02, with a bacterial activity of 1×10⁻⁶. 11 CFU / g.

[0067] The preparation method of the soil conditioner is the same as in Example 2-1.

[0068] Example 2-3

[0069] A soil conditioner, by mass percentage, comprises: 95.0% tobacco straw, 2.0% *Ulva prolifera* polysaccharide, 0.5% brown algae oligosaccharide, and 2.5% Bacillus cereus powder.

[0070] The Bacillus powder consists of Bacillus amyloliquefaciens Cas02 and Bacillus subtilis Tpb55, and the total bacterial activity of the Bacillus powder is 1×10⁻⁶. 11 CFU / g, wherein the mass ratio of Bacillus amyloliquefaciens Cas02 to Bacillus subtilis Tpb55 is 1:1.

[0071] The preparation method of the soil conditioner is the same as in Example 2-1.

[0072] Examples 2-4

[0073] A soil conditioner, by mass percentage, comprises: 96.3% tobacco straw, 1.0% *Ulva prolifera* polysaccharide, 0.2% *Alginate* oligosaccharide, and 2.5% *Bacillus* powder.

[0074] The Bacillus powder consists of Bacillus amyloliquefaciens Cas02, Bacillus subtilis Tpb55, and Bacillus belyss EM-1, with a total bacterial activity of 1×10⁻⁶. 11 CFU / g, wherein the mass ratio of Bacillus amyloliquefaciens Cas02, Bacillus subtilis Tpb55 and Bacillus bereaves EM-1 in the Bacillus powder is 1:1:1.

[0075] The preparation method of the soil conditioner is the same as in Example 2-1.

[0076] Example 3-1

[0077] Remediation of coastal saline soil using the soil conditioner of Example 2-1

[0078] The physicochemical properties of coastal saline soil are as follows: bulk density 1.31 g / cm³ 3 The composition of the sample is as follows: porosity 50%, electrical conductivity 1.065 ds / m, pH 7.62, ammonium nitrogen 11.82 mg / kg, nitrate nitrogen 3.36 mg / kg, organic matter 10.17 g / kg, available phosphorus 9.39 mg / kg, and salt content 0.5%.

[0079] The soil conditioner of Example 2-1 was added to the coastal saline soil at a ratio of 5% of the mass of the coastal saline soil and incubated for 1 month. During the incubation process, the soil moisture was kept at about 60%. After the incubation was completed, peanuts were planted as experimental group 1. Eight parallel experiments were conducted, that is, each group of experiments included eight potted plants.

[0080] After germination, peanut seeds were placed in the soil of experimental group 1 and cultivated in a greenhouse (light conditions: 16h, 28℃; darkness conditions: 8h, 20℃; relative humidity 60%). Each plant was watered with approximately 100mL of sterilized water per week.

[0081] Example 3-2

[0082] The soil conditioner of Example 2-1 was used to remediate coastal saline soil. The specific method was the same as that of Example 3-1, except that the soil conditioner of Example 2-1 was added to the coastal saline soil at a ratio of 10% of the mass of the coastal saline soil, which was used as experimental group 2.

[0083] Example 3-3

[0084] The soil conditioner of Example 2-1 was used to remediate coastal saline soil. The specific method was the same as that of Example 3-1, except that the soil conditioner of Example 2-1 was added to the coastal saline soil at a ratio of 20% of the mass of the coastal saline soil, which was used as experimental group 3.

[0085] Comparative Example 1

[0086] Peanuts that have been germinated were cultured in coastal saline soil without the addition of soil conditioners as a control group. The specific culture method was the same as in Example 3-1.

[0087] Application Example 1

[0088] The growth of peanut seedlings after five weeks of culture in Examples 3-1 to 3-3 and Comparative Example 1 is as follows: Figure 2 As shown, where Figure 2 From left to right, the groups are: control group (Comparative Example 1), 5% soil conditioner addition group (Example 3-1), 10% soil conditioner addition group (Example 3-2), and 20% soil conditioner addition group (Example 3-3). After 5 weeks of cultivation, the agronomic traits of peanut seedlings in Examples 3-1 to 3-3 and Comparative Example 1, such as main stem height, number of lateral branches, root length, and plant dry weight, were statistically analyzed.

[0089] After 5 weeks of cultivation, the agronomic traits of peanut seedlings in Examples 3-1 to 3-3 and Comparative Example 1 after 5 weeks of cultivation are shown in Table 3.

[0090] Table 3. Agronomic traits of peanut seedlings in Examples 3-1 to 3-3 and Comparative Example 1 after 5 weeks of cultivation.

[0091] Group deal with Main stem height / cm Number of lateral branches / each Root length / cm Plant dry weight / g Comparative Example 1 control group 6.10±0.21d 3.96±0.14d 10.49±1.46c 0.3210±0.0197d Example 3-1 5% Soil Conditioner 8.38±0.19b 5.63±0.13b 15.84±1.18b 0.3761±0.0241b Example 3-2 10% Soil Conditioner 10.00±0.26a 7.10±0.14a 17.98±1.81a 0.3919±0.0280a Example 3-3 20% Soil Conditioner 7.83±0.20bc 5.14±0.15c 16.55±1.26b 0.3573±0.0285b

[0092] Note: Different letters in the same column indicate significant differences.

[0093] Depend on Figure 2As shown in Table 3, when soil conditioner is added at 10% of the mass of coastal saline soil, peanut growth is optimal, showing a significant growth advantage compared to the control group.

[0094] Examples 3-4

[0095] The soil conditioner of Example 2-2 was used for the remediation of coastal saline soil, and the specific method was the same as that of Example 3-2.

[0096] Examples 3-5

[0097] The soil conditioners of Examples 2-3 were used for the remediation of coastal saline soil, and the specific methods were the same as those in Examples 3-2.

[0098] Examples 3-6

[0099] The soil conditioners of Examples 2-4 were used for the remediation of coastal saline soil, and the specific methods were the same as those in Examples 3-2.

[0100] Application Example 2

[0101] Table 4 shows the growth of peanut seedlings after five weeks of cultivation in Examples 3-2, 3-4 to 3-6 and Comparative Example 1.

[0102] Table 4. Growth of peanut seedlings after five weeks of culture in Examples 3-2, 3-4 to 3-6, and Comparative Example 1.

[0103] Group Main stem height / cm Number of lateral branches / each Root length / cm Plant dry weight / g Comparative Example 1 6.10±0.21b 3.96±0.14b 10.49±1.46c 0.3210±0.0197b Examples 3-4 10.02±0.33a 6.80±0.16a 16.58±1.12b 0.3678±0.0160a Example 3-2 10.00±0.26a 7.10±0.21a 17.98±1.81a 0.3919±0.0280a Examples 3-5 9.88±0.16a 6.56±0.08a 16.22±1.24b 0.3789±0.0140a Examples 3-6 9.96±0.13a 6.44±0.11a 17.68±0.71a 0.3822±0.0240a

[0104] As shown in Table 4, the content range of each component in the soil conditioner of the present invention can be defined as follows: tobacco straw 95%–97%, Ulva polysaccharide 0.5%–2%, brown algae oligosaccharide 0.1%–0.5%, and Bacillus powder 1%–2.5%. Within the above range, the soil conditioner can effectively improve the soil.

[0105] Comparative Example 2

[0106] Eight parallel experiments were conducted by adding 1‰ of the mass fraction of *Ulva prolifera* polysaccharide and 0.2‰ of the mass fraction of *Alginate* oligosaccharide to coastal saline soil.

[0107] The germinated peanuts were planted in the above-treated coastal saline soil for cultivation, using the same cultivation method as in Example 3-1.

[0108] Comparative Example 3

[0109] Eight parallel experiments were conducted by adding 1‰ of the mass fraction of *Ulva prolifera* polysaccharide and 2.5‰ of the mass fraction of *Bacillus* to the coastal saline soil.

[0110] The composition of Bacillus is the same as in Example 2.

[0111] The germinated peanuts were planted in the above-treated coastal saline soil for cultivation, using the same cultivation method as in Example 3-1.

[0112] Comparative Example 4

[0113] Eight parallel experiments were conducted by adding 2.5‰ Bacillus subtilis to coastal saline soil.

[0114] The composition of Bacillus is the same as in Example 2.

[0115] The germinated peanuts were planted in the above-treated coastal saline soil for cultivation, using the same cultivation method as in Example 3-1.

[0116] Comparative Example 5

[0117] Eight parallel experiments were conducted by adding 9.63% tobacco straw (by mass) to coastal saline soil.

[0118] The germinated peanuts were planted in the above-treated coastal saline soil for cultivation, using the same cultivation method as in Example 3-1.

[0119] Comparative Example 6

[0120] Eight parallel experiments were conducted by adding 9.63% tobacco straw and 2.5‰ Bacillus subtilis to coastal saline soil.

[0121] The composition of Bacillus is the same as in Example 2.

[0122] The germinated peanuts were planted in the above-treated coastal saline soil for cultivation, using the same cultivation method as in Example 3-1.

[0123] Comparative Example 7

[0124] Eight parallel experiments were conducted by adding 1‰ of the mass fraction of *Ulva prolifera* polysaccharide, 0.2‰ of the mass fraction of *Bryophyllaria* oligosaccharide, and 2.5‰ of the mass fraction of *Bacillus* to coastal saline soil.

[0125] The composition of Bacillus is the same as in Example 2.

[0126] The germinated peanuts were planted in the above-treated coastal saline soil for cultivation, using the same cultivation method as in Example 3-1.

[0127] Application Example 3

[0128] After 5 weeks of cultivation, the agronomic traits of peanut seedlings in Examples 3-2 and Comparative Examples 1-6, such as main stem height, number of lateral branches, root length, and plant dry weight, were statistically analyzed.

[0129] After 5 weeks of cultivation, the agronomic traits of peanut seedlings in Examples 3-2 and Comparative Examples 1-6 are shown in Table 5.

[0130] Table 5. Agronomic traits of peanut seedlings after 5 weeks of cultivation in Examples 3-2 and Comparative Examples 1-6.

[0131]

[0132] Note: Different letters indicate significant differences.

[0133] Table 5 shows that the application of only *Ulva prolifera* polysaccharide and fucoidan oligosaccharide had no significant effect on the growth of peanut seedlings in coastal saline soil. Similarly, the application of *Bacillus* alone also had no significant effect on peanut seedling growth. However, the combined application of *Ulva prolifera* polysaccharide and *Bacillus* significantly promoted the growth of peanut seedlings compared to the application of *Bacillus* alone, resulting in improvements in main stem height, number of lateral branches, root length, and plant dry weight. Tobacco straw had a significant promoting effect on the growth of peanut seedlings in coastal saline soil. However, the combined application of *Bacillus* and tobacco straw did not show a significant change compared to the application of tobacco straw alone. This invention, by applying tobacco straw together with *Ulva prolifera* polysaccharide, fucoidan oligosaccharide, and *Bacillus*, significantly promoted the growth of peanut seedlings compared to other control groups, significantly increasing the main stem height, number of lateral branches, root length, and dry weight. This demonstrates the synergistic effect of tobacco straw, *Ulva prolifera* polysaccharide, fucoidan oligosaccharide, and *Bacillus* in promoting plant growth.

[0134] Application Example 4

[0135] Field yield test

[0136] The experiment adopted a single-factor randomized block design, with 3 rows × 50 plants per plot, 120cm row spacing, and 3 replicates (i.e., each plot has 3 rows with a row spacing of 120cm, 50 peanut plants per row, one set of experiments per plot, and 3 parallel sets of experiments per experiment).

[0137] The experiment consisted of two treatments: an experimental group and a control group.

[0138] The experimental group was treated as follows: the soil conditioner in Example 2-1 was added to the coastal saline soil at a ratio of 10% of the mass of the coastal saline soil and incubated under natural conditions for 2 months, and then peanuts were planted. Conventional fertilization was carried out during the peanut planting process.

[0139] The control group was treated by planting peanuts directly in coastal saline soil and applying conventional fertilizers during the peanut planting process.

[0140] The experimental and control groups were treated with the same routine fertilization methods, and other field management practices were carried out in accordance with local traditional practices. The treatments for the two groups were exactly the same.

[0141] Peanut yields in the experimental and control groups were measured after harvest.

[0142] The yield results of the field trials for the experimental and control groups are shown in Table 6.

[0143] Table 6. Field experimental yield data for the experimental and control groups.

[0144] deal with Peanut pod weight (g / plant) Several peanut pods per plant control group 30.25±2.67b 20.15±1.89b experimental group 58.60±3.44a 30.78±2.11a

[0145] As shown in Table 6, adding soil conditioner can significantly increase peanut yield.

[0146] Application Example 5

[0147] Field yield measurement was conducted to investigate the effects of soil conditioners on microbial diversity and soil physicochemical properties in coastal saline soils.

[0148] Experimental group: The soil conditioner from Example 2-1 was added to the coastal saline soil at a ratio of 10% of its mass in March. Under natural conditions, it was incubated for two months. After incubation, soil samples were collected for physicochemical property testing. The results of the physicochemical property testing of the experimental and control groups are shown in Table 7. Peanuts were sown in May, and soil samples were collected after peanut harvest. Microbial diversity in the soil was detected through sequencing. Sequencing was commissioned to Meiji Company.

[0149] Control group: Coastal saline soil without soil conditioner was set up as a control. Other treatment conditions were the same as above, namely, peanuts were sown in May, and the soil was collected after peanut harvest. The microbial diversity in the soil was detected by sequencing.

[0150] The effect of adding a soil conditioner at a ratio of 10% of the mass of coastal saline soil on the microbial diversity of coastal saline soil is as follows: Figure 3 As shown.

[0151] Depend on Figure 3 It can be seen that the application of soil conditioners can significantly improve the soil microbial community and enhance the microbial diversity of saline soil.

[0152] Table 7. Effects of adding soil conditioner on the physical and chemical properties of coastal saline soil.

[0153] Group pH <![CDATA[NH4 + -N]]> Soil bulk density Soil porosity CK 8.11±0.04a 10.28±1.04b 1.32±0.10a 50％b Soil conditioner 7.62±0.02ab 38.99±1.28a 1.10±0.03b 58％a

[0154] As shown in Table 7, the physical and chemical properties of coastal saline soil were significantly improved after the addition of soil conditioner, which is beneficial for subsequent peanut planting.

[0155] In summary, the soil conditioner provided by this invention can effectively improve the diversity of microorganisms in coastal saline soil through the synergistic effect of its various components, solve the problem of slow or no plant growth under coastal saline soil conditions, and promote plant growth and development.

[0156] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. The application of a soil conditioner in improving coastal saline soil, said soil conditioner comprising, by weight percentage: The composition includes 95%–97% tobacco straw, 0.5%–2% Ulva prolifera polysaccharide, 0.1%–0.5% fucoidan oligosaccharide, and 1%–2.5% Bacillus spore powder. The Bacillus species include one or more of Bacillus amyloliquefaciens, Bacillus subtilis, and Bacillus belye; the total viability of the Bacillus species is ≥1×10⁻⁶. 10 CFU / g; The *Bacillus amyloliquefaciens* includes *Bacillus amyloliquefaciens* Cas02, whose preservation number is CGMCC NO.15514; the *Bacillus subtilis* includes *Bacillus subtilis* Tpb55, whose preservation number is CGMCC NO.2853; the *Bacillus belyss* includes *Bacillus belyss* EM-1, whose preservation number is CGMCC NO.21131.

2. The application according to claim 1, characterized in that, The soil conditioner comprises the following components by weight percentage: The composition includes 96.3% tobacco straw, 1.0% Ulva prolifera polysaccharide, 0.2% fucoidan oligosaccharide, and 2.5% Bacillus spore powder.

3. The application as described in claim 1 or 2, characterized in that, The method for preparing the soil conditioner includes the following steps: After the tobacco straw is crushed, it is mixed with seaweed polysaccharide, brown algae oligosaccharide and Bacillus powder to obtain a soil conditioner.

4. The application according to claim 3, characterized in that, The particle size of the crushed tobacco straw is <5cm.

5. The application according to claim 1, characterized in that, The application also includes promoting plant growth in coastal saline soils; the plants include peanuts.

6. The application according to claim 1, characterized in that, The method of using the soil conditioner includes: Soil conditioner is added to coastal saline soil at a ratio of 5% to 20% by weight.

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