Pantoea agglomerans and application thereof in improvement of saline-alkali soil

Abstract

The invention relates to the field of saline-alkali soil improvement, in particular to pantoea agglomerans and application thereof in saline-alkali soil improvement. The method for improving the saline-alkali soil comprises the following steps that ditching and ridging are conducted on saline-alkali soil, concave ditches are dug in ridges, sweet potatoes are planted on the two sides of the concave ditches, and a microbial agent is added into the concave ditches after the sweet potatoes are planted; the preparation method of the microbial agent comprises the following steps: by taking a pantoea agglomerans suspension as a core material, mixing the core material with an encapsulation carrier, and then preparing the pantoea agglomerans liposome by adopting a hot spraying manner, the encapsulated carrier comprises chitosan, polyglycerol fatty acid ester and ceramide, and uniformly mixing the pantoea agglomerans liposome with the microbial agent carrier to obtain the microbial agent; the microbial agent carrier is prepared by mixing wheat bran, charcoal and activated carbon. By adopting the improvement method disclosed by the invention, the effect of obviously reducing the salinity of the saline-alkali soil can be achieved, and meanwhile, the activity of beta-glucosidase and sucrase of the soil can be improved.

Description

Technical Field

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

[0002] Saline-alkali land refers to land in which the soil contains excessive soluble salts, resulting in soil salinization or alkalization. The saline-alkali land in China is mainly distributed in arid, semi-arid and coastal areas, which are often important areas for agricultural production. With the growth of the population and the acceleration of the urbanization process, land resources are becoming increasingly tense, and the improvement and utilization of saline-alkali land have become an important way to relieve the pressure on land resources. At the same time, the improvement of saline-alkali land also helps to improve the local ecological environment, increase biodiversity, and promote ecological balance.

[0003] At present, the saline-alkali land improvement technologies are mainly divided into several categories: physical improvement, chemical improvement and biological improvement. Physical improvement technologies mainly reduce the impact of salts on crops by changing the physical structure of the soil. Common methods include leveling the ground, deep plowing and sunning the soil, timely loosening of the soil, raising the ground level, micro-area soil improvement, tree hole soil improvement, etc. These measures can improve the soil permeability and promote the leaching and discharge of salts. In addition, there is also the method of flooding and washing, that is, watering large amounts of water on saline-alkali soil in winter and spring to dilute and wash the soil salts. However, physical improvement technologies have obvious limitations. First of all, physical improvement measures often require a large amount of water resources, manpower and material resources, and the cost is high. Secondly, physical improvement can only temporarily reduce the salts on the soil surface and cannot fundamentally change the saline-alkali nature of the soil. Once the improvement measures are stopped, the soil salts are likely to accumulate again. Finally, excessive physical improvement measures may also damage the soil structure and affect the soil ecological balance.

[0004] Chemical improvement technologies mainly regulate the soil pH by adding chemical improvers to improve 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 improvers can react with the salts in the soil to form insoluble salt precipitates, thereby reducing the salt content in the soil. However, chemical improvement technologies also have defects. First of all, the use of chemical improvers may bring secondary pollution problems. For example, excessive acidic fertilizers will cause soil acidification and affect crop growth. Secondly, the effects of chemical improvers often last for a short time and need to be applied regularly to maintain the soil environment. Finally, some chemical improvers have a high cost, increasing the cost burden of saline-alkali land improvement.

[0005] Biological improvement techniques mainly improve the soil environment by utilizing the life activities of microorganisms and plants. Microorganisms can improve the physical and chemical properties of the soil, enhance soil fertility and crop stress resistance by secreting organic acids, enzymes and other substances. Salt-tolerant plants can adapt to saline-alkali environments through their special physiological mechanisms and reduce soil salinity by absorbing and transferring salts through their roots. Biological improvement techniques have the advantages of environmental protection and sustainability, and are an important direction for saline-alkali land improvement. However, biological improvement techniques also face many challenges. First, the breeding and cultivation of salt-tolerant plants require a long time, and the effects are affected by various factors such as soil environment and climate conditions. Second, the screening and domestication of microbial strains are also a complex process, and it is necessary to find microbial strains suitable for saline-alkali land environments and ensure their stable growth and reproduction in high-salt environments. Finally, the effects of biological improvement techniques often take a long time to appear, which is a challenge for saline-alkali lands that urgently need to improve agricultural production capacity.

[0006] Existing saline-alkali land improvement techniques have many defects. For example, soil flooding irrigation may result in the loss of a large amount of nutrients, which has an adverse impact 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 above-mentioned existing technologies and provide a Pantoea Pantoea sp. and its application in improving saline-alkali land. The preservation number of the Pantoea is CCTCC NO: M2012340, and the taxonomic name is Pantoea sp. Y4-4 Pantoea sp. Y4-4 was deposited at 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] The application of Pantoea Pantoea sp. in improving saline-alkali land, the preservation number of the Pantoea is CCTCC NO: M2012340, preservation date: September 12, 2012, preservation unit: China Center for Type Culture Collection (CCTCC), taxonomic name: Pantoea sp. Y4-4 Pantoea sp. Y4-4, preservation location: Wuhan University, Wuhan, China.

[0010] A method for improving saline-alkali land, comprising the following steps: digging trenches and ridges in saline-alkali soil, digging concave trenches on the ridges, planting sweet potatoes on both sides of the concave trenches, and adding microbial inoculants to the concave trenches after planting sweet potatoes;

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

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

[0013] Further, the microbial inoculum is added 2 weeks and 5 weeks after planting sweet potatoes respectively.

[0014] Further, a drip irrigation belt is laid in the middle of the concave groove.

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

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

[0017] Further, the nozzle temperature adopted by the thermal spraying method is 40 °C.

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

[0019] Further, the total application amount of the microbial inoculum per mu of land is 10 kg.

[0020] Beneficial effects

[0021] The present invention for the first time applies Pantoea agglomerans (CCTCC NO: M2012340) to the improvement of saline-alkali land. The cells of Pantoea agglomerans are straight rods, with peritrichous flagella and are motile. This motility helps its diffusion and distribution in the soil, thus reacting more effectively with salts and nutrients in the soil. Pantoea agglomerans is a facultative anaerobe, which can ferment 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, participate in chemical reactions in the soil, and neutralize the alkalinity in the soil. This is of great significance for improving the soil environment of saline-alkali land. During the growth process, Pantoea agglomerans promotes the decomposition of soil organic matter, thus increasing the total amount of soil organic matter. This helps improve the physical structure of the soil, enhance the soil's water and nutrient retention capacity, and provide a better environment for plant growth. Pantoea agglomerans can enhance the plant's defense ability against pests and diseases by producing substances such as antibiotics, phenols, and reactive oxygen species. At the same time, it may also maintain the osmotic pressure balance of cells and reduce the damage of saline-alkali stress to plants by promoting the accumulation of osmotic regulators. These functions all help improve the plant's stress resistance and survival ability on saline-alkali land.

[0022] The microbial inoculant prepared by the method of the present invention participates in the chemical reaction of salts in the soil by releasing specific active substances such as organic acids and polysaccharides. The insoluble salts produced help reduce the salinity of the soil. This biochemical process is of great significance for adjusting the soil microenvironment, especially for the adverse effects on plants under high saline-alkali conditions. During the growth process of soil microorganisms, they promote the decomposition of soil organic matter, thus increasing the total amount of soil organic matter. The increase in soil organic matter not only helps improve the physical structure of the soil, but also enhances the soil's water and nutrient retention capacity, which is crucial for plant growth.

[0023] For saline-alkali stress, the microbial inoculant helps maintain the osmotic pressure balance of cells and reduce the damage of saline-alkali stress to plants by promoting the accumulation of osmotic regulators such as proline and soluble sugars. The metabolites of microorganisms can also regulate the hormone levels in plants and enhance their resistance to various adversities. For example, under drought conditions, the microbial inoculant can promote the accumulation of drought-resistant compounds in plants and improve their drought tolerance. Under other adversities, such as cold and high-temperature conditions, the microbial inoculant can also improve the plant's stress resistance through various mechanisms to ensure its growth and development under adverse conditions.

[0024] As a microencapsulation technology, liposomes can form a protective film to wrap Pantoea agglomerans cells, thus effectively preventing the cells from being directly damaged by the external environment, such as adverse factors like ultraviolet rays, high temperature, and dryness. Pantoea agglomerans cells encapsulated by liposomes have stronger stress resistance in saline-alkali soil environments, can better adapt to extreme conditions such as high salt and high alkalinity, and thus improve their survival rate and colonization ability in the soil. Liposomes can enhance the adhesion ability between the cells and soil particles, promoting the colonization of the cells in the soil. The colonized Pantoea agglomerans can carry out its metabolic activities to improve the physical and chemical properties of the soil, such as reducing the salt content and increasing soil fertility. After the liposome-encapsulated Pantoea agglomerans cells are mixed with the microbial agent carrier, they can continuously release and reproduce in the soil, forming a stable microbial community, thereby continuously improving saline-alkali soil and enhancing the ecological service function of the soil.

[0025] In the present invention, Pantoea agglomerans is prepared into liposomes, which are simultaneously mixed with a microbial agent carrier and inoculated in the rhizosphere of sweet potato. By promoting the growth of sweet potato seedlings and improving the salt tolerance of sweet potato seedlings, it can effectively reduce the soil salt content. It has the effect of increasing the content of soil organic carbon (SOC) in saline soil and simultaneously reducing the content of soil dissolved organic carbon (DOC), indicating that the soil carbon changes from easily decomposable organic carbon to stable organic carbon, which is beneficial to the accumulation and stability of soil organic carbon and has a good carbon sequestration effect.

[0026] The wide and high ridges constructed in the present invention, with concave grooves on the ridge surface, can significantly increase the acceptance capacity of natural precipitation and enhance the soil water storage capacity; especially under conditions of a large amount of precipitation, the surface runoff of the non-ridged soil is large and the horizontal water loss is fast. The natural precipitation received by the wide and high ridge method and the water supply through the drip irrigation belt can effectively leach the soil salt in the surface layer of saline-alkali soil vertically downward, thus significantly reducing the soil salt in the surface root area and reducing the stress of soil salt on the roots. Combined with the added microbial agent, it can not only reduce the soil salt content but also comprehensively improve the survival ability of sweet potato in saline-alkali soil, improve the growth status of sweet potato, increase the biomass of sweet potato including the biomass of tuberous roots, and further remove more soil salt from the perspective of plant salt extraction, further reducing the soil salt content. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a photograph of the double-row wide and high ridge of the present invention;

[0028] Figure 2 It is a comparison schematic diagram of ridging between Example 1 and Comparative Example 1 of the present invention;

[0029] Figure 3 It is a field actual photo of Example 1 and Comparative Example 1 of the present invention (the photo does not show the entire field scene);

[0030] Figure 4This is the field actual photo of Embodiment 2 of the present invention (the photo does not show the entire field scene).

[0031] Biomaterial preservation information: Pantoea sp. Pantoea sp., preservation number: CCTCC NO: M2012340, preservation date: September 12, 2012, preservation unit: China Center for Type Culture Collection (CCTCC), taxonomic naming: Pantoea sp. Y4-4 Pantoea sp. Y4-4, preservation location: Wuhan University, Wuhan, China. Detailed implementation manners

[0032] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will describe in conjunction with the embodiments of the present invention.

[0033] Embodiment 1

[0034] A method for improving saline-alkali land includes the following steps: digging trenches and ridging the saline-alkali soil. The ridges are double-row high-width 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. Concave trenches are dug on the ridges. The concave trenches are in an inverted trapezoid shape, with an upper base of 15 cm, a lower base of 5 cm, and a trapezoid height of 10 cm. Water retaining dams are built at both ends of the concave trenches of each ridge. A drip irrigation tape is laid in the middle of the concave trenches, as Figure 1 shown. Sweet potatoes are planted on both sides of the concave trenches. Microbial inoculants are added to the concave trenches 2 weeks and 5 weeks after planting the sweet potatoes.

[0035] The preparation method of the microbial inoculant includes: using the Pantoea sp. suspension as the core material, mixing the core material and the encapsulation carrier, and preparing Pantoea sp. liposomes by a thermal spraying method; the mass ratio of the core material to 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 sp. liposomes are uniformly mixed with the inoculant carrier to obtain the microbial inoculant. The mass ratio of the Pantoea sp. liposomes to the inoculant carrier is 1:8. The inoculant carrier is prepared by mixing wheat bran, charcoal, and activated carbon, and the mass ratio of wheat bran, charcoal, and activated carbon is 1:1:1. The total application amount of the microbial inoculant per mu of land is 10 kg; Pantoea Pantoea sp. preservation number is CCTCC NO: M2012340, and the taxonomic naming is Pantoea sp. Y4-4 Pantoea sp. Y4-4 was preserved in the China Center for Type Culture Collection (CCTCC) on September 12, 2012; the preservation location is Wuhan University, Wuhan, China; the effective viable count of the Pantoea sp. suspension is 10 8 cfu / g.

[0036] Control group: No measures were taken.

[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 were planted in the conventional narrow ridge and single row method, 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 concave grooves were dug on the ridge, single row planting was carried out, and no microbial inoculant was added. The rest was exactly the same as in Example 1. The differences between it and Example 1 are as 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 were planted in the conventional narrow ridge and single row method, 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 concave grooves were dug on the ridge, single row planting was carried out, and Pantoea agglomerans was not prepared into Pantoea agglomerans liposomes. Instead, the Pantoea agglomerans bacterial suspension was directly mixed with the inoculant carrier. The rest was 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 were planted in the conventional narrow ridge and single row method, 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 concave grooves were dug on the ridge, single row planting was carried out, and the rest was exactly the same as in 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 inoculant was added, and the rest was exactly the same as in 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 Pantoea agglomerans was not prepared into Pantoea agglomerans liposomes. Instead, the Pantoea agglomerans bacterial suspension was directly mixed with the inoculant carrier. The rest was exactly the same as in 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 inoculant carrier was added, and the dosage of Pantoea agglomerans liposomes used was the same as in Example 1. The rest of the steps were exactly the same as 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 potatoes were planted, and the rest of the steps were 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: the microbial inoculum was added 2 weeks after planting sweet potatoes, and the rest was exactly the same as in 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: the microbial inoculum was added 5 weeks after planting sweet potatoes, and the rest was exactly the same as in Example 1.

[0055] Example 2

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

[0057] The plots with similar soil conditions were selected from the above plots and grouped. Each group was set with 3 replicate areas. One of the groups was selected as the control without any treatment, and the remaining groups were respectively used to improve the soil by the methods of the examples and comparative examples. As Figure 4 shown, the soil was collected 5 months after planting sweet potatoes, and the salt content, soil β-glucosidase and soil sucrase activities in the soil were analyzed and measured.

[0058] Table 1

[0059]

[0060] The above results show that by using the improvement method of the present invention, good effects of salt reduction and improvement of soil β-glucosidase and soil sucrase activities can be achieved.

[0061] Example 3

[0062] The test plot is located in the farm of Rudong Yulongchang Agricultural Science and Technology Co., Ltd., Rudong County, Jiangsu Province, and its salt content is 0.53%. The plots with similar soil conditions were selected from the above plots and grouped. Each group was set with 3 replicate areas. One of the groups was selected as the control without any treatment, and the remaining groups were respectively used to improve the soil by the methods of the examples and comparative examples. After planting sweet potatoes for 6 months, the soil organic matter, soil organic carbon (SOC) and dissolved organic carbon (DOC) contents were counted.

[0063] Table 2

[0064]

[0065] The effects of the improved method of the present invention on soil DOC and SOC are shown in the above table. The results indicate that the improved method of 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 transforms from labile organic carbon to stable organic carbon, which is beneficial to the accumulation and stability of soil SOC and has a good carbon sequestration effect.

Claims

1. Pantoea agglomerans Pantoea sp. Application in improving saline-alkali land, characterized in that, The Pantoea agglomerans has a deposit number of CCTCC NO: M2012340 and is taxonomically named Pantoea agglomerans sp. Y4-4, which was deposited at the China Center for Type Culture Collection on September 12, 2012. Pantoea sp. Y4-4 2. A method for improving saline-alkali land, characterized in that, comprises the following steps: Dig trenches and form ridges in saline-alkali soil, dig concave grooves on the ridges, plant sweet potatoes on both sides of the concave grooves, and add microbial inoculants into the concave grooves after planting sweet potatoes; The preparation method of the microbial inoculum includes: using Pantoea agglomerans bacterial suspension as the core material, mixing the core material and the encapsulation carrier, and preparing Pantoea agglomerans liposome by thermal spraying; the encapsulation carrier includes chitosan, polyglycerol fatty acid ester and ceramide, uniformly mixing the Pantoea agglomerans liposome with the inoculum carrier to obtain the microbial inoculum; the inoculum carrier is prepared by mixing wheat bran, charcoal and activated carbon; the preservation number of the Pantoea agglomerans is CCTCC NO: M2012340, and the taxonomic name is Pantoea sp. Y4-4 Pantoea which was deposited in China Center for Type Culture Collection on September 12, 2012; the effective viable count of the Pantoea agglomerans bacterial suspension is 10 8 ~10 9 cfu / g.

3. The method for improving saline-alkali land according to claim 2, wherein The ridge height is 35 cm, the top width of the ridge is 45 cm, the bottom width of the ridge is 80 cm, and the ridge spacing is 110 cm; the concave groove is in an inverted trapezoid shape, with the upper base being 15 cm, the lower base being 5 cm, and the trapezoid height being 10 cm; water retaining dams are built at both ends of the concave grooves of each ridge.

4. The method for improving saline-alkali land according to claim 2, characterized in that, Microbial inoculants are added 2 weeks and 5 weeks after planting sweet potatoes respectively.

5. The method for improving saline-alkali land according to claim 2, wherein Lay drip irrigation tapes in the middle of the concave grooves.

6. The method for improving saline-alkali soil according to claim 2, characterized in that, The mass ratio of the core material to the encapsulation carrier is 1:

5.

7. The method for improving saline-alkali land according to claim 2, wherein, The mass ratio of chitosan, polyglycerol fatty acid ester and ceramide is 8:2:

1.

8. The method for improving saline-alkali land according to claim 2, wherein The nozzle temperature adopted by the hot spray method is 40 °C.

9. The method for improving saline-alkali land according to claim 2, wherein, The mass ratio of the Pantoea liposome to the inoculant carrier is 1:8; the mass ratio of wheat bran, charcoal and activated carbon is 1:1:

1.

10. The method for improving saline-alkali land according to claim 2, wherein, The total application amount of microbial inoculants per mu of land is 10 kg.

Images