A kind of Pantoea agglomerata and its application in improving saline-alkali land

Abstract

The present invention relates to the field of saline-alkali soil improvement, and specifically relates to a Pantoea agglomerata and its application in improving saline-alkali land. The method for improving saline-alkali land provided by the present invention comprises the following steps: digging trenches and ridges on the saline-alkali soil, digging trenches on the ridges, planting sweet potatoes on both sides of the trenches, and adding microbial agents into the trenches after planting the sweet potatoes; the preparation method of the microbial agent comprises: using a Pantoea agglomerata suspension as a core material, mixing the core material and an encapsulation carrier, and then preparing a Pantoea agglomerata liposome by a thermal spraying method; the encapsulation carrier comprises chitosan, polyglycerol fatty acid ester and ceramide, uniformly mixing the Pantoea agglomerata liposome with the agent carrier to obtain a microbial agent; the agent carrier is prepared by mixing wheat bran, charcoal and activated carbon. By adopting the improvement method of the present invention, the effect of significantly reducing the salinity of saline-alkali soil can be achieved, and at the same time, the activity of soil β-glucosidase and soil sucrase can be improved.

Description

Technical Field

[0001] The present invention relates to the field of soil improvement, and in particular to Pantoea agglomerata and its application in improving saline-alkali land. Background Art

[0002] Saline-alkali land refers to land with excessive amounts of soluble salts, resulting in salinization or alkalinization. China's saline-alkali land is primarily distributed in arid, semi-arid, and coastal areas, which are often important for agricultural production. With population growth and accelerated urbanization, land resources are becoming increasingly scarce. Improving saline-alkali land utilization has become a key approach to alleviating this pressure. Furthermore, improving saline-alkali land can help improve the local ecological environment, enhance biodiversity, and promote ecological balance.

[0003] Currently, saline-alkali land improvement technologies are primarily categorized into physical, chemical, and biological improvement. Physical improvement primarily reduces the impact of salt on crops by altering the soil's physical structure. Common methods include leveling the ground, deep plowing and sun-drying, timely loosening the soil, raising the ground, micro-area soil improvement, and tree pit soil improvement. These measures can improve soil permeability and facilitate the leaching and drainage of salt. Another approach is flooding, which involves applying large amounts of water to salinized soil in winter and spring to dilute and flush out the salt. However, physical improvement techniques have significant limitations. First, physical improvement measures often require significant investments in water resources, manpower, and materials, resulting in high costs. Second, physical improvement can only temporarily reduce the salt content in the soil's surface layer and cannot fundamentally change the salinization of the soil. Once improvement measures are discontinued, soil salt easily accumulates again. Finally, excessive physical improvement measures can damage soil structure and affect the soil's ecological balance.

[0004] Chemical improvement technology mainly adjusts the pH of the soil by adding chemical amendments, thereby improving the soil environment. Common methods include applying acidic fertilizers such as desulfurized gypsum and superphosphate, as well as humic acid-type soil improvers. These chemical amendments can react chemically with the salt in the soil to form insoluble salt precipitates, thereby reducing the salt content in the soil. However, chemical improvement technology also has defects. First, the use of chemical amendments may cause secondary pollution problems. For example, excessive acidic fertilizers will cause soil acidification and affect crop growth. Secondly, the effects of chemical amendments are often short-lived and require regular application to maintain the soil environment. Finally, some chemical amendments are expensive, which increases the cost burden of saline-alkali land improvement.

[0005] Bioremediation technology primarily improves the soil environment by harnessing the life activities of microorganisms and plants. Microorganisms can improve soil physical and chemical properties by secreting substances such as organic acids and enzymes, enhancing soil fertility and crop resistance. Salt-tolerant plants, on the other hand, adapt to saline-alkali environments through their specialized physiological mechanisms and reduce soil salinity by absorbing and transferring salt through their roots. Bioremediation technology offers advantages such as environmental friendliness and sustainability, making it an important approach for improving saline-alkali land. However, bioremediation technology also faces numerous challenges. First, the breeding and cultivation of salt-tolerant plants is time-consuming, and its effectiveness is influenced by multiple factors, including soil environment and climatic conditions. Second, the screening and domestication of microbial strains is a complex process, requiring identification of strains suited to saline-alkali soil environments and ensuring their ability to grow and reproduce stably in these high-salt environments. Finally, the effects of bioremediation technology often take a long time to manifest, presenting a challenge for saline-alkali lands that urgently need to improve agricultural productivity.

[0006] Existing saline-alkali land improvement technologies have many defects. For example, soil flooding may cause a large loss of nutrients, which will have an adverse effect on plant growth. Therefore, there is an urgent need to provide a method that is beneficial to plant growth in the soil and can effectively reduce the salt content in the soil. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a Pantoea sp. and its application in improving saline-alkali land. The Pantoea agglomerata is deposited with CCTCC NO: M2012340 and is classified as Pantoea agglomerata Y4-4 Pantoea sp. Y4-4, which was deposited in the China Center for Type Culture Collection (CCTCC) on September 12, 2012.

[0008] To achieve the purpose of the present invention, the technical solution adopted by the present invention is:

[0009] Pantoea agglomerata Pantoea sp. in improving saline-alkali land. The Pantoea agglomerata is deposited with CCTCC NO: M2012340, date of deposit: September 12, 2012, deposited by China Center for Type Culture Collection (CCTCC), and classified as Pantoea agglomerata Y4-4. Pantoea sp. Y4-4, deposited at Wuhan University, Wuhan, China.

[0010] A method for improving saline-alkali land comprises the following steps: digging trenches and forming ridges on the saline-alkali soil, digging trenches on the ridges, planting sweet potatoes on both sides of the trenches, and adding microbial agents into the trenches after the sweet potatoes are planted;

[0011] The preparation method of the microbial agent comprises: using a suspension of Pantoea agglomerans as a core material, mixing the core material with an encapsulation carrier, and then preparing Pantoea agglomerans liposomes by thermal spraying; the encapsulation carrier comprises chitosan, polyglycerol fatty acid ester, and ceramide, and uniformly mixing the Pantoea agglomerans liposomes with the agent carrier to obtain the microbial agent; the agent carrier is prepared by mixing wheat bran, charcoal, and activated carbon; the Pantoea agglomerans has a preservation number of CCTCC NO: M2012340 and is classified as Pantoea Y4-4 Pantoea sp. Y4-4, deposited in China Center for Type Culture Collection on September 12, 2012; the effective viable count of the Pantoea agglomerata suspension was 10 8 ~10 9 cfu / g.

[0012] Furthermore, the ridge height is 35cm, the ridge top width is 45cm, the ridge bottom width is 80cm, and the ridge spacing is 110cm; the ditch is in an inverted trapezoidal shape, with an upper bottom of 15cm, a lower bottom of 5cm, and a trapezoidal height of 10cm; water retaining dams are built at both ends of the ditch of each ridge.

[0013] Furthermore, microbial agents were added 2 weeks and 5 weeks after the sweet potato was planted.

[0014] Furthermore, a drip irrigation tape is laid in the middle of the ditch.

[0015] Furthermore, the mass ratio of the core material to the encapsulation carrier is 1:5.

[0016] Furthermore, the mass ratio of the chitosan, polyglycerol fatty acid ester and ceramide is 8:2:1.

[0017] Furthermore, the nozzle temperature used in the thermal spraying method is 40°C.

[0018] Furthermore, the mass ratio of the Pantoea liposomes to the bacterial agent carrier is 1:8; the mass ratio of wheat bran, charcoal and activated carbon is 1:1:1.

[0019] Furthermore, the total amount of microbial agent applied per mu of land is 10 kg.

[0020] Beneficial effects

[0021] This study is the first to apply Pantoea agglomerans (CCTCC NO: M2012340) to improve saline-alkali land. Pantoea agglomerans cells are straight rods with peritrichous flagella, enabling them to move. This motility facilitates their diffusion and distribution within the soil, allowing them to more effectively react with salt and nutrients. Pantoea agglomerans is a facultative anaerobic bacterium that ferments D-glucose and other sugars to produce acid but not gas. This fermentation ability helps it produce active substances such as organic acids in the soil, participating in chemical reactions and neutralizing soil alkalinity. This is of great significance for improving the soil environment in saline-alkali land. During its growth, Pantoea agglomerans promotes the decomposition of soil organic matter, thereby increasing the total amount of soil organic matter. This helps improve the soil's physical structure and enhance its water and nutrient retention capacity, providing an optimal environment for plant growth. Pantoea agglomerans can enhance plant defenses against pests and diseases by producing substances such as antibiotics, phenols, and reactive oxygen species. Furthermore, it may promote the accumulation of osmoregulators, maintaining cellular osmotic pressure and mitigating damage to plants caused by saline-alkali stress. These functions all help to improve the stress resistance and survival ability of plants in saline-alkali soil.

[0022] The microbial inoculant prepared by the method of the present invention releases specific active substances, such as organic acids and polysaccharides, which participate in chemical reactions with salt in the soil. The resulting insoluble salts help reduce soil salinity. This biochemical process is important for regulating the soil microenvironment, particularly in the adverse effects of high salinity and alkalinity on plants. During their growth, soil microorganisms promote the decomposition of soil organic matter, thereby increasing the total amount of soil organic matter. This increase in soil organic matter not only helps improve the soil's physical structure but also enhances its ability to retain water and nutrients, which is crucial for plant growth.

[0023] In response to saline-alkali stress, microbial agents help maintain cellular osmotic pressure balance and mitigate damage to plants by promoting the accumulation of osmotic regulators such as proline and soluble sugars. Microbial metabolites can also regulate hormone levels in plants, enhancing their resistance to various adversities. For example, in drought conditions, microbial agents can promote the accumulation of drought-resistant compounds in plants, improving their drought tolerance. In other adverse conditions, such as cold and high temperatures, microbial agents can also enhance plant resistance through various mechanisms, ensuring growth and development under adverse conditions.

[0024] As a microencapsulation technology, liposomes form a protective film that encapsulates Pantoea agglomerans, effectively protecting them from direct damage from external environmental factors such as ultraviolet light, high temperatures, and dryness. Liposome-encapsulated Pantoea agglomerans exhibit enhanced stress resistance in saline-alkali environments, better adapting to extreme conditions such as high salt and alkalinity, thereby improving their survival rate and colonization in the soil. Liposomes enhance the adhesion of the bacteria to soil particles, promoting their colonization. Once colonized, Pantoea agglomerans can exert their metabolic activities and improve the physical and chemical properties of the soil, such as reducing salt content and increasing soil fertility. When mixed with a microbial agent carrier, the liposome-encapsulated Pantoea agglomerans are continuously released and reproduced in the soil, forming a stable microbial community, thereby continuously improving saline-alkali soil and enhancing its ecological services.

[0025] The present invention prepares Pantoea agglomerans into liposomes, mixes the liposomes with a bacterial agent carrier, and inoculates the liposomes into the rhizosphere of sweet potatoes. This promotes the growth of sweet potato seedlings and improves the salt tolerance of sweet potato seedlings. At the same time, it can effectively reduce the salt content of the soil, increase the soil organic carbon (SOC) content of saline soil, and reduce the soluble organic carbon (DOC) content of the soil. This indicates that the soil carbon is transformed from easily decomposable organic carbon to stable organic carbon, which is beneficial to the accumulation and stabilization of soil organic carbon and has a good carbon sequestration effect.

[0026] The wide and high ridges constructed by the present invention, with grooves on the ridge surface, can significantly increase the ability to receive natural precipitation and increase the soil's water storage capacity; especially under conditions of heavy precipitation, the surface runoff of unridged soil is large, and the horizontal loss of water is rapid. The natural precipitation received by the high and wide ridges and the water supply through the drip irrigation belt can effectively wash the salt in the surface soil of the saline-alkali soil vertically downward, thereby significantly reducing the effect of soil salt in the surface root area and reducing the stress of soil salt on the root system. Combined with the added microbial agents, it can not only reduce the salt content of the soil, but also comprehensively improve the survival ability of sweet potatoes in saline-alkali soil, improve the growth of sweet potatoes, increase the biomass of sweet potatoes, including tuberous root biomass, and then remove more soil salt from the perspective of plant extraction of salt, further reducing the soil salt content. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a photo of the double-row high and wide ridges described in the present invention;

[0028] Figure 2 Schematic diagram comparing ridging of Example 1 of the present invention and Comparative Example 1;

[0029] Figure 3 Actual field photos of Example 1 of the present invention and Comparative Example 1 (the photos do not show the entire field scene);

[0030] Figure 4This is a real picture of the field according to Example 2 of the present invention (the photo does not show the entire field scene).

[0031] Biomaterial deposit information: Pantoea Pantoea sp., deposit number: CCTCC NO: M2012340, deposit date: September 12, 2012, deposited by: China Center for Type Culture Collection (CCTCC), classification name: Pantoea Y4-4 Pantoea sp. Y4-4, deposited at Wuhan University, Wuhan, China. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described below.

[0033] Example 1

[0034] A method for improving saline-alkali land comprises the following steps: digging trenches and forming ridges on the saline-alkali soil, wherein the ridges are double-row high and wide ridges, with a ridge height of 35 cm, a ridge top width of 45 cm, a ridge bottom width of 80 cm, and a ridge spacing of 110 cm. A groove is dug on the ridge, the groove being in the shape of an inverted trapezoid, with an upper bottom of 15 cm, a lower bottom of 5 cm, and a trapezoidal height of 10 cm. A water retaining dam is built at both ends of the groove of each ridge, and a drip irrigation belt is laid in the middle of the groove, such as Figure 1 Sweet potatoes were planted on both sides of the grooves, and microbial agents were added into the grooves 2 and 5 weeks after planting the sweet potatoes.

[0035] The preparation method of the microbial agent includes: using a suspension of Pantoea agglomerans as a core material, mixing the core material and an encapsulation carrier, and then preparing Pantoea agglomerans liposomes by thermal spraying; the mass ratio of the core material and the encapsulation carrier is 1:5; the encapsulation carrier includes chitosan, polyglycerol fatty acid ester and ceramide, and the mass ratio of chitosan, polyglycerol fatty acid ester and ceramide is 8:2:1; the nozzle temperature used in the thermal spraying method is 40°C. The Pantoea agglomerans liposomes and the agent carrier are uniformly mixed to obtain a microbial agent. The mass ratio of the Pantoea agglomerans liposomes to the agent carrier is 1:8. The agent carrier is prepared by mixing wheat bran, charcoal and activated carbon, wherein the mass ratio of wheat bran, charcoal and activated carbon is 1:1:1. The total amount of microbial agent applied per mu of land is 10 kg; Pantoea agglomerans Pantoea sp. The deposit number is CCTCC NO: M2012340, and the classification name is Pantoea Y4-4 Pantoea sp. Y4-4, deposited in China Center for Type Culture Collection (CCTCC) on September 12, 2012; the deposited location is Wuhan University, Wuhan, China; the effective viable cell count of the Pantoea agglomerata suspension is 10 8 cfu / g.

[0036] Control group: no measures were applied.

[0037] Comparative Example 1

[0038] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that sweet potatoes are planted in a conventional narrow ridge single row manner, with a ridge height of 30 cm, a ridge top width of 20 cm, a ridge bottom width of 50 cm, a ridge spacing of 80 cm, no trenches are dug on the ridges, single row planting is performed, and no microbial agent is added. The rest is exactly the same as in Example 1. The difference between this comparative example and Example 1 is as follows: Figure 2 and 3 shown.

[0039] Comparative Example 2

[0040] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that sweet potatoes are planted in a conventional narrow ridge single row manner, with a ridge height of 30 cm, a ridge top width of 20 cm, a ridge bottom width of 50 cm, and a ridge spacing of 80 cm. No trenches are dug on the ridges, and the planting is done in a single row. Pantoea agglomerata is not prepared into Pantoea agglomerata liposomes, and the Pantoea agglomerata suspension is directly mixed with the bacterial agent carrier. The rest is exactly the same as in Example 1.

[0041] Comparative Example 3

[0042] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that sweet potatoes are planted in a conventional narrow ridge single row manner, with a ridge height of 30 cm, a ridge top width of 20 cm, a ridge bottom width of 50 cm, a ridge spacing of 80 cm, no trenches are dug on the ridges, and single row planting is used. The rest is exactly the same as Example 1.

[0043] Comparative Example 4

[0044] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that no microbial agent is added, and the rest is exactly the same as Example 1.

[0045] Comparative Example 5

[0046] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that the Pantoea agglomerata is not prepared into Pantoea agglomerata liposomes, and the Pantoea agglomerata suspension is directly mixed with the bacterial agent carrier. The rest is exactly the same as Example 1.

[0047] Comparative Example 6

[0048] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that no bacterial agent carrier is added, the amount of Pantoea agglomerata liposomes used is the same as that in Example 1, and the remaining steps are exactly the same as those in Example 1.

[0049] Comparative Example 7

[0050] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that no sweet potato is planted, and the remaining steps are exactly the same as in Example 1.

[0051] Comparative Example 8

[0052] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that a microbial agent is added 2 weeks after the sweet potato is planted, and the rest is exactly the same as Example 1.

[0053] Comparative Example 9

[0054] A method for improving saline-alkali land. The difference between this comparative example and Example 1 is that a microbial agent is added 5 weeks after the sweet potato is planted, and the rest is exactly the same as Example 1.

[0055] Example 2

[0056] The test site is located in Heken Village, Cangcha Town, Rudong County, Nantong City, Jiangsu Province (32°36′59″N, 120°55′52″E). This is saline-alkali land. The soil pH is 7.9, and the salt content in the 0-20 cm tillage layer is 0.54%. Nutrient deficiency, high soil salinity, and low soil organic matter content are the main obstacles to crop production in this plot.

[0057] The plots with similar soil conditions were grouped into groups, with three replicates set up in each group. One of the groups was selected as a control and was not treated. The soil in the other groups was improved using the methods of the embodiment and comparative example, as shown in FIG. Figure 4 As shown, soil was collected 5 months after sweet potato planting, and the soil salt content, soil β-glucosidase and soil sucrase activities were analyzed and determined.

[0058] Table 1

[0059]

[0060] The above results show that the improved method of the present invention can achieve better effects of reducing salt and improving the activities of soil β-glucosidase and soil sucrase.

[0061] Example 3

[0062] The test site was located on the farm of Rudong Yulongchang Agricultural Technology Co., Ltd. in Rudong County, Jiangsu Province, and had a salt content of 0.53%. The aforementioned plots were grouped with plots of similar soil conditions, with three replicates set up in each group. One group was selected as a control and received no treatment. The remaining groups were treated with soil improvement methods from the Examples and Comparative Examples, respectively. Six months after sweet potato cultivation, soil organic matter, soil organic carbon (SOC), and soluble organic carbon (DOC) contents were measured.

[0063] Table 2

[0064]

[0065] The effects of the improvement method described in the present invention on soil DOC and SOC are shown in the table above. The results show that the improvement method described in the present invention can significantly increase the organic matter content and soil SOC content of saline soil, but reduce the soil DOC content, indicating that soil carbon is transformed from easily decomposable organic carbon to stable organic carbon, which is beneficial to the accumulation and stabilization of soil SOC and has a good carbon sequestration effect.

Claims

1. A method for improving saline-alkali land, characterized in that: The following steps are involved: Dig trenches and ridges on saline-alkali soil, dig trenches on the ridges, plant sweet potatoes on both sides of the trenches, and add microbial agents into the trenches after planting the sweet potatoes; The preparation method of the microbial agent comprises: using a suspension of Pantoea agglomerans as a core material, mixing the core material with an encapsulation carrier, and then preparing Pantoea agglomerans liposomes by thermal spraying; the encapsulation carrier comprises chitosan, polyglycerol fatty acid ester, and ceramide, and uniformly mixing the Pantoea agglomerans liposomes with the agent carrier to obtain the microbial agent; the agent carrier is prepared by mixing wheat bran, charcoal, and activated carbon; the Pantoea agglomerans has a preservation number of CCTCC NO: M2012340 and is classified as Pantoea Y4-4 Pantoea sp. Y4-4, deposited in China Center for Type Culture Collection on September 12, 2012; the effective viable count of the Pantoea agglomerata suspension was 10 8 ~10 9 cfu / g.

2. The method for improving saline-alkali land according to claim 1, characterized in that: The ridge height is 35cm, the top width is 45cm, the bottom width is 80cm, and the ridge spacing is 110cm; the ditch is in an inverted trapezoidal shape, with an upper bottom of 15cm, a lower bottom of 5cm, and a trapezoidal height of 10cm; water retaining dams are built at both ends of the ditch of each ridge.

3. The method for improving saline-alkali land according to claim 1, characterized in that: Microbial agents were added 2 weeks and 5 weeks after planting the sweet potatoes.

4. The method for improving saline-alkali land according to claim 1, characterized in that: Lay the drip irrigation tape in the middle of the groove.

5. The method for improving saline-alkali land according to claim 1, characterized in that: The mass ratio of the core material to the encapsulation carrier is 1:

5.

6. The method for improving saline-alkali land according to claim 1, characterized in that: The mass ratio of the chitosan, polyglycerol fatty acid ester and ceramide is 8:2:

1.

7. The method for improving saline-alkali land according to claim 1, characterized in that: The nozzle temperature used in the thermal spraying method is 40°C.

8. The method for improving saline-alkali land according to claim 1, characterized in that: The mass ratio of the Pantoea liposomes to the bacterial agent carrier is 1:8; the mass ratio of wheat bran, charcoal and activated carbon is 1:1:

1.

9. The method for improving saline-alkali land according to claim 1, characterized in that: The total amount of microbial agent applied per mu of land is 10 kg.

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