Method for planting sunflowers in severe saline-alkali soil

Abstract

The invention relates to a method for planting sunflowers in severe saline-alkali soil, which comprises the following steps of: improving field soil of the severe saline-alkali soil by using a biological agent containing bacillus megatherium TZ-1 with the preservation number of CGMCC (China General Microbiological Culture Collection Center) NO.22296, taking a slender matrix bag filled with fully decomposed sheep manure as a seedling pot, and planting sunflower seeds into matrix soil of the seedling pot; the slender matrix bag is a kraft paper bag, the caliber of the paper bag is 1.9 + / -0.2 cm, and the height of the paper bag is 15 + / -1.0 cm; the depth of the sunflower seeds dibbled into the seedling pot matrix soil is 3 + / -0.2 cm; the slender matrix bag is planted into a field during field sowing. Planting experiments prove that the method has a remarkable improvement effect on the plant height and leaf area of the sunflowers planted in the saline-alkali soil, the emergence rate of the sunflowers can be effectively increased, the empty shell and shrunken seed rate is reduced, the number of seeds in a single disc is increased, and then the acre yield is remarkably increased.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and in particular relates to a method for planting sunflowers in severe saline-alkali land. Background Art

[0002] Saline-alkali land refers to a type of land that contains too much soluble salt or alkaline substances in the soil, which affects the growth of plants. The negative impacts of saline-alkali land on crop growth include, but are not limited to, difficulty in water absorption, lack of nutrients, and stunted root development. Given the importance of sunflower as an oil crop and its economic value worldwide, studies have shown that sunflower has a certain salt tolerance, but this ability is limited and it still faces many challenges in severe saline-alkali land.

[0003] In the saline-alkali land of the Hetao Irrigation Area, due to strong evaporation, salt moves upward with water and accumulates on the soil surface. The average salt content of the surface soil of the saline-alkali land in the Hetao area decreases with increasing depth, while the water content increases with increasing depth. Generally, the sowing depth of sunflowers is 3-5 cm. The excessive salt ions and pH value in the surface soil cause stress to sunflowers, affecting the emergence rate and limiting the growth and development of sunflower plants. Therefore, how to increase the yield of sunflowers on severely saline-alkali land is of great significance to the further utilization of saline-alkali land and to increase the total yield of sunflowers.

[0004] The physical and chemical properties of soil in severe saline-alkali land are extreme, with high pH and conductivity. The expansion of clay particles leads to a decrease in porosity, a decrease in oxygen diffusion rate, accumulation of salt ions, and disintegration of the chloroplast grana lamellae structure, which leads to crop metabolic disorders, decreased expression of the proline synthase gene (P5CS), and inhibition of SOD enzyme activity. In the high pH environment of saline-alkali land, most of the phosphorus will be fixed in the soil to form insoluble compounds, reducing the effectiveness of phosphorus. Since the soil conditions in saline-alkali land are not conducive to microbial activity, the process of converting organic nitrogen into a form that can be used by plants is limited. At the same time, high concentrations of sodium ions may also have an adverse effect on the absorption of ammonium nitrogen by plants. In addition, potassium in saline-alkali land usually exists in the form of mineral potassium, making it difficult for potassium to be directly absorbed and utilized by plants.

[0005] Traditional methods for improving saline-alkali land mainly include physical and chemical methods, such as gypsum improvement, salt drainage through underground pipes, and biochar. Among them, gypsum improvement is not only costly but also ineffective. Salt drainage through underground pipes cannot fundamentally solve the problem of high soil salinity. Biochar will reduce salt content while also causing the fixation and loss of effective phosphorus in the soil. Microbial preparations are an important soil improvement method, a technical trend that uses microorganisms to improve soil conditions, especially the mechanism of action of beneficial microorganisms that can promote plant growth and improve stress resistance. However, common salt-tolerant strains (such as Bacillus subtilis XZ173) currently have problems such as single function and difficulty in rhizosphere colonization due to osmotic pressure shock. Summary of the invention

[0006] 1. Technical issues to be resolved In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an application of Bacillus megaterium in planting sunflowers in severe saline-alkali land. The Bacillus megaterium has excellent potassium solubilization, IAA production, phosphorus solubilization, nitrogen fixation and other effects under saline-alkali stress, and can be used to promote the emergence and growth and development of sunflowers in severe saline-alkali land, thereby playing a positive role in improving the utilization rate of saline-alkali land and the yield of sunflowers.

[0007] (II) Technical solution The present invention provides an application of Bacillus megaterium in planting sunflowers in severe saline-alkali land. The Bacillus megaterium is (Bacillus megaterium) TZ-1, whose deposit number is CGMCC NO.22296 (recorded in the prior patent application CN115710561A), has the functions of solubilizing potassium, producing IAA, solubilizing phosphorus and fixing nitrogen under saline-alkali stress to promote the emergence and growth and development of sunflower in severely saline-alkali land.

[0008] According to a preferred embodiment of the present invention, the application includes: before planting sunflowers, adding the Bacillus megaterium or a microbial preparation containing the Bacillus megaterium to a soil layer depth of 0-20 cm in the sunflower planting soil to pre-improve the heavily saline-alkali soil.

[0009] In a second aspect, the present invention provides a method for planting sunflowers in severe saline-alkali land, comprising: using a biological bacterial agent containing Bacillus megaterium with a preservation number of CGMCC NO.22296 to improve the field soil of the severe saline-alkali land, and using an elongated substrate bag filled with fully decomposed sheep manure as a seedling pot, and planting sunflower seeds in the substrate soil of the seedling pot; when sowing in the field, planting the seedling pot in the field.

[0010] According to a preferred embodiment of the present invention, the landfill depth of the biological agent is in the range of 0-20 soil layer depth of field soil.

[0011] According to a preferred embodiment of the present invention, the elongated substrate bag is a kraft paper bag with a diameter of 1.9±0.2 cm and a height of 15±1.0 cm; the depth of sunflower seeds planted in the substrate soil of the seedling pot is 3±0.2 cm.

[0012] According to a preferred embodiment of the present invention, the planting density in the field is 1200 plants / mu, and a transparent plastic film is applied before the seedlings emerge.

[0013] Phosphorus solubilization: refers to the ability of certain microorganisms to secrete organic acids or other compounds that convert insoluble phosphates in the soil into soluble phosphates, thereby increasing the effectiveness of phosphorus and making it easier for plants to absorb and utilize it.

[0014] Potassium dissolving: refers to the ability of some microorganisms to decompose potassium-containing minerals (such as feldspar and mica) and release potassium ions that can be absorbed by plants. These microorganisms destroy the mineral structure by producing specific enzymes or acidic metabolites, thereby increasing the content of available potassium in the soil.

[0015] Nitrogen fixation: refers to the ability of certain microorganisms (such as rhizobia) to convert atmospheric nitrogen into ammonia, which is then used to synthesize amino acids and other nitrogen-containing compounds for plant absorption and utilization. This is particularly important in environments where nitrogen fertilizer is scarce.

[0016] (III) Beneficial effects Bacillus megaterium with the deposit number CGMCC NO.22296 in the prior patent application CN115710561A (Bacillus megaterium) TZ-1 has the effect of improving the quality of alfalfa crude protein and reducing the content of neutral and acidic detergent fiber, but its effect in improving heavy saline-alkali soil has not been further developed. (Bacillus megaterium) TZ-1 is used to dissolve potassium and phosphorus, produce IAA, and fix nitrogen in saline-alkali soil. It is used to promote the emergence and growth of sunflowers in severely saline-alkali soil, thereby playing a positive role in improving the utilization rate of saline-alkali land and the yield of sunflowers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 These are Gram staining experiment diagrams of several potassium-solubilizing bacteria.

[0018] Figure 2 The curves of potassium-solubilizing ability of several potassium-solubilizing bacteria changing with time.

[0019] Figure 3 This is a quantitative analysis of the potassium-solubilizing ability of several potassium-solubilizing bacteria under alkaline stress.

[0020] Figure 4 This is a quantitative analysis of the potassium-solubilizing ability of several potassium-solubilizing bacteria under salt stress.

[0021] Figure 5 It is a standard curve for quantitative analysis of the phosphate-solubilizing ability of several phosphate-solubilizing bacteria.

[0022] Figure 6 Gram staining experiment diagram of several phosphate-solubilizing bacteria.

[0023] Figure 7 The invention discloses a substrate bag used for planting sunflowers in heavy saline-alkali land. DETAILED DESCRIPTION

[0024] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0025] The Bacillus megaterium of the present invention has been experimentally confirmed to have excellent potassium-solubilizing ability even under saline-alkali stress; when dissolving phosphorus, it is different from conventional phosphate-solubilizing bacteria in that it does not decompose insoluble phosphates by secreting acid, but directly hydrolyzes organic phosphorus ester bonds to achieve efficient phosphorus dissolution, so that its pH value does not drop significantly, and the strain can dissolve phosphorus while avoiding further acidification and destruction of the soil microenvironment.

[0026] Example 1

[0027] The potassium-solubilizing ability of Bacillus was determined by sodium tetraphenylborate turbidimetry.

[0028] Take KCl standard stock solution (0, 100, 200, 300, 400, 500, 600) μl and put it into a test tube, add water to 1 mL, add 0.2 mL of acetic acid-sodium acetate buffer solution (pH 4.5) and 0.8 mL of 4% sodium tetraphenylborate solution to each tube, shake well to form a uniform, slightly milky white transparent sol. Measure its absorbance at 520 nm, that is, OD value. Use absorbance as the horizontal axis and the potassium content of the corresponding standard solution as the vertical axis to draw a potassium standard curve.

[0029] Add 50mL of Aleksandrov medium to a 250mL conical flask and sterilize at 121℃ for 20min. Perform aseptic operation and inoculate the tested bacteria into each bottle. At the same time, make a blank control without bacteria (the control group is CK), and culture them at 30℃ and 200r / min for 7 days. The tested bacteria include four strains of Bacillus with potassium-solubilizing potential isolated and screened from the sunflower planting soil at the experimental base of the Meteorological Bureau of Wuyuan County, Bayannur City, Inner Mongolia Autonomous Region. They are named 15-18, 15-17, 14-7 and TZ-1 (the preservation number is CGMCCNO.22296). The separation method is: take 0.5 grams of soil 10cm below the ground where sunflowers are planted, add 30mL of sterile water and shake well to obtain a dispersion, and shake for 10 1 -10 8 Gradient dilution, gradually dilute the concentration of bacteria in the dispersion; take 100μL of the gradient diluted dispersion, apply it on the LB plate (LB culture medium) separately with a scraper, and place the plate at 28℃ constant temperature for culture until a single colony grows. One of the strains was identified as Bacillus megaterium TZ-1.

[0030] Take 1.5mL of bacterial solution at 6500r / min, centrifuge for 5min, take 1mL of supernatant in a test tube, add 0.2mL of acetic acid-sodium acetate buffer solution and 0.8mL of 4% sodium tetraphenylborate solution, shake well to form a uniform, slightly milky white transparent sol. At a wavelength of 520nm, in a 1cm cuvette, use the negative control (uninoculated culture solution) as the reference solution to measure the absorbance of the sol. According to the regression line equation of the standard working curve, calculate the potassium chloride content and potassium dissolution rate in the tested bacterial solution.

[0031] As shown in Table 1: Strain number Average potassium release Potassium release rate (%) 15-18 21.27±1.49ab 17.51% 15-17 21.76±0.8ab 20.22% 14-7 22.01±1.85ab 21.60% TZ-1 25.14±2.68a 38.90% CK 18.43±0.04b 0 Note: Different letters indicate significant differences between the two phases; the same letters indicate the opposite.

[0032] The above table shows that among the several strains finally obtained in the same screening process, Bacillus megaterium TZ-1 has the best potassium-solubilizing ability.

[0033] At the same time, samples were taken from the bacterial liquid after 7 days of culture to determine the IAA (indoleacetic acid) content. The IAA production of Bacillus megaterium TZ-1 was 15.40 mg / L, and the IAA production of Bacillus 15-17 was 4.71 mg / L. Indoleacetic acid is the most important natural growth hormone in plants, and strains with high IAA content will be beneficial to seed germination and plant growth.

[0034] Furthermore, the four strains of potassium-solubilizing bacteria were subjected to Gram staining experiments. The experimental results are as follows: Figure 1 As shown, after staining, the following images were obtained under a microscope. From left to right, they are Bacillus megaterium TZ-1, Bacillus 15-18, Bacillus 14-7 and Bacillus 15-17. It can be seen from the observation that all four strains are Bacillus. Among them, Bacillus megaterium TZ-1 was stained blue-purple, which is a Gram-positive bacterium, and the other strains of Bacillus potassium-soluble 15-18, 14-7, and 15-17 were stained red, indicating that they are Gram-negative bacteria.

[0035] Furthermore, in order to reduce the influence of various factors on the determination results, three sets of repeated experiments were carried out to obtain the change curve of potassium solubilization ability of the above four strains of bacteria over time. Figure 2 It can be seen that the growth curve of Bacillus megaterium TZ-1 has a high slope and a high growth rate from the third to the fifth day. Among the four strains of Bacillus studied, Bacillus megaterium TZ-1 has the largest growth rate, and its culture fluid has the highest K content, with the best potassium-solubilizing ability.

[0036] Example 2

[0037] In order to further investigate the potassium-releasing ability of Bacillus megaterium TZ-1 and several other Bacillus species under high alkalinity and high salt stress, this example, based on Example 1, adds alkali and salt to the culture medium of the tested bacteria, respectively. The alkali uses three concentrations of NaHCO3, 50mM, 75mM and 100mM, and the salt uses three concentrations of NaCl, 200mM, 250mM and 300mM. According to the method of Example 1, the strain to be tested is added and cultured at 30°C and 200r / min for 7 days, and the potassium chloride content in the bacterial solution is measured. The test results are as follows: Figure 3-4 shown.

[0038] like Figure 3 As shown, under different concentrations of alkali stress conditions, the potassium content in the bacterial solution of Bacillus megaterium TZ-1 is the highest. Among them, under 50mM NaHCO3 stress conditions, the potassium concentration in the bacterial solution of Bacillus megaterium TZ-1 is about 24mM, under 75mM NaHCO3 stress conditions, the potassium concentration in the bacterial solution of Bacillus megaterium TZ-1 is about 23mM, and under 100mM NaHCO3 stress conditions, the potassium concentration in the bacterial solution of Bacillus megaterium TZ-1 is about 21mM. Under high alkali stress, Bacillus megaterium TZ-1 has the best potassium solubilization ability, followed by Bacillus 14-17 and 15-18, and the worst potassium solubilization ability is Bacillus 15-17.

[0039] like Figure 4 As shown, under different concentrations of salt stress conditions, the potassium content in the bacterial solution of Bacillus megaterium TZ-1 is the highest. Among them, under 200mM NaC1 stress conditions, the potassium concentration in the bacterial solution of Bacillus megaterium TZ-1 is about 24.6mM, under 250mM NaC1 stress conditions, the potassium concentration in the bacterial solution of Bacillus megaterium TZ-1 is about 23.8mM, and under 300mM NaC1 stress conditions, the potassium concentration in the bacterial solution of Bacillus megaterium TZ-1 is about 22.7mM. Under high salt stress, Bacillus megaterium TZ-1 has the best potassium-solubilizing ability, followed by Bacillus 14-17 and 15-17, and the worst potassium-solubilizing ability is Bacillus 15-18. Figure 3 and Figure 4 It can be seen that under alkaline stress and salt stress conditions, the strain with the worst potassium solubilization ability changed, which shows that the same strain may show different potassium solubilization abilities under different environmental stress conditions. In summary, Bacillus megaterium TZ-1 has the best potassium solubilization ability under salt-alkali stress.

[0040] Example 3

[0041] Seven strains of Bacillus with phosphate-solubilizing potential were isolated and screened from the sunflower planting soil at the experimental base of the Meteorological Bureau of Wuyuan County, Bayannur City, Inner Mongolia Autonomous Region, and were named L6, JL122, JL78, 175, 272, JL67 and TZ-1 (the deposit number is CGMCC NO.22296). The isolation method is as described above. The solubility of the above-mentioned phosphate-solubilizing bacteria on lecithin and tricalcium phosphate was tested. After the strains selected above were streaked on LB medium, they were cultured in a liquid medium shaker for 7 days, and their phosphate-solubilizing capacity was determined.

[0042] The ability of Bacillus to degrade inorganic phosphorus was determined by the vanadium molybdenum yellow colorimetric method. Take 0, 10, 20, 40, 100 μl of phosphoric acid stock solution and put it into a test tube. Add water to 2.5 mL. Add 2.0 mL of color stop solution to each tube, shake well, heat in a 37°C water bath for 30 minutes to fully develop color. After cooling, measure with a colorimeter at 440 nm and record the absorbance. Use the absorbance as the horizontal axis and the phosphorus content of the corresponding standard solution as the vertical axis to draw a phosphorus standard curve (such as Figure 5 as shown).

[0043] Add 50mL of Montkina organic phosphorus liquid medium (lecithin for organic phosphorus) or Montkina inorganic phosphorus liquid medium (tricalcium phosphate for inorganic phosphorus) to a 250mL triangular flask and sterilize at 115℃ for 30min. Perform aseptic operation, inoculate the tested bacteria into each bottle, and make a blank control without bacteria inoculation. All of them are cultured at 30℃ and 200r / min for 7 days. Set up 3 parallels for each group, and finally take the average value. At the same time, set up a blank control. After the culture is completed, take 1mL of bacterial solution at 6500 r / min, centrifuge for 5min, take 0.8mL of supernatant and add it to a test tube containing 1.7mL of distilled water, then add 2mL of color stop solution to stop the reaction, keep warm in a 37℃ water bath for 30min, measure its OD value at 440nm with a spectrophotometer after color development, and then read the phosphorus content according to the phosphorus standard curve (the phosphorus content in the solution is the amount of phosphorus dissolved), and measure the pH of the bacterial solution after the culture is completed. The test results are shown in Table 2-3.

[0044] Table 2: Phosphate solubilization amount of phosphate-solubilizing bacteria L6, JL122, JL78, and TZ-1 in the Mengjina organic phosphorus liquid medium and the pH of the bacterial solution after 7 days of culture serial number average value Corresponding phosphorus concentration (mg / L) Available phosphorus content in solution Phosphorus solubilization pH L6 0.020 0.072 89.721% 22.153% 3.83 JL122 0.020 0.072 89.721% 22.153% 3.93 JL78 0.019 0.070 87.875% 23.999% 3.92 TZ-1 0.016 0.062 77.721% 34.153% 6.31 Organophosphate blank 0.028 0.089 111.874% / 7.16

[0045] serial number average value Corresponding phosphorus concentration (mg / L) Available phosphorus content in solution Phosphorus solubilization pH 175 0.067 0.177 8.832% 5.686% 6.98 272 0.069 0.181 9.053% 5.908% 6.95 JL67 0.024 0.081 4.032% 0.886% 6.01 TZ-1 0.210 0.493 49.269% 46.123% 4.53 Inorganic phosphorus blank 0.016 0.063 3.146% / 7.96

[0046] As shown in Table 2-3, after the cultivation, the pH of the blank medium of Montkina organic phosphorus and inorganic phosphorus was 7.16 and 7.96 respectively. Among them, the pH of each strain of phosphate-solubilizing bacteria decreased when cultivated in Montkina medium. The pH was between 3.83-6.31 in Montkina organic phosphorus liquid medium and between 4.53-6.98 in Montkina inorganic phosphorus liquid medium. The pH values ​​of the bacterial liquid of L6, JL122 and JL78 of phosphate-solubilizing bacteria decreased significantly in Montkina organic phosphorus liquid medium, which decreased by 3.33, 3.23 and 3.22 respectively; the pH of the bacterial liquid of Bacillus megaterium TZ-1 decreased the least, which only decreased by 0.85. This shows that when Bacillus megaterium TZ-1 uses organic phosphorus (lecithin), it does not dissolve organic phosphorus by the traditional method of secreting a large amount of organic acid, but directly produces enzymes to decompose insoluble lecithin, directly hydrolyze organic phosphorus ester bonds, and convert organic phosphorus into a form that can be absorbed by plants (that is, increase the effective phosphorus content in the solution). In the inorganic phosphorus culture medium, the pH drop of the bacterial solution of Bacillus megaterium TZ-1 was the largest, dropping by 3.43. This shows that in highly alkaline soil, Bacillus megaterium TZ-1 can not only dissolve phosphorus, but also reduce the pH in alkaline soil, making the pH of alkaline soil close to neutral. It is an advantageous strain for alkaline soil remediation. In addition, from the perspective of phosphorus solubilization ability, Bacillus megaterium TZ-1 has the best phosphorus solubilization ability for both organic and inorganic phosphorus, and has the highest phosphorus solubilization efficiency and applicability. In an environment where organic and inorganic phosphorus coexist, the Bacillus megaterium TZ-1 can hydrolyze organic phosphorus ester bonds by secreting organic phosphorus phospholytic enzymes without causing a large pH fluctuation, and can secrete acid to dissolve inorganic phosphorus.

[0047] Furthermore, the seven strains of phosphate-solubilizing bacteria L6, JL122, JL78, 175, 272, JL67 and TZ-1 were subjected to Gram staining. The experimental results are as follows: Figure 6 As shown. After Gram staining, the morphology of phosphate-solubilizing bacteria L6, JL122, JL78, 175, 272, JL67, and Bacillus megaterium TZ-1 is shown Figure 6 The results of Gram staining showed that L6, JL122, JL78, 175, 272, and JL67 were all Gram-negative bacteria, while Bacillus megaterium TZ-1 was a Gram-positive bacterium.

[0048] Example 4

[0049] Through visual observation, Bacillus megaterium TZ-1 grew vigorously on Ashby nitrogen-free medium, with rapid colony expansion and full morphology, and produced a large number of colonies in a short period of time, with good growth ability and ability to adapt to the environment. In order to evaluate the nitrogenase functional activity of Bacillus megaterium TZ-1, the acetylene reduction method was used in combination with the measurement method of gas chromatography, and the nitrogenase activity data of Bacillus megaterium TZ-1 was successfully obtained. The nitrogenase activity of Bacillus megaterium TZ-1 was 281.53 nmoL / mL*h -1 , but still showed a fairly strong nitrogen fixation ability.

[0050] In LB liquid culture medium, Bacillus megaterium TZ-1 was cultured for 2 days and a blank control was set up, and the pH values ​​of the experimental group and the control group were measured. The pH of the bacterial solution of Bacillus megaterium TZ-1 was 7.29 (5.70 for the control group), and the absorbance of Bacillus megaterium TZ-1 was observed to be 0.18 at the wavelength of OD600 (0.01 for the control group). This shows that Bacillus megaterium TZ-1 also has good growth potential in different culture media, and the pH value of the bacterial solution is above 7, showing a neutral to alkaline characteristic.

[0051] Example 5

[0052] The present embodiment provides a method for planting sunflowers in severe saline-alkali land, comprising: using a microbial agent of Bacillus megaterium TZ-1 to improve the field soil of the severe saline-alkali land, and using an elongated substrate bag filled with fully decomposed sheep manure as a seedling pot, and planting sunflower seeds in the substrate soil of the seedling pot; when sowing in the field, planting the seedling pot in the field.

[0053] The test site is located at the experimental base of the Wuyuan County Meteorological Bureau in Bayannur City, Inner Mongolia Autonomous Region, China. The annual sunshine hours are 3263 hours, the average temperature is 6.1℃, and the accumulated temperature is 3362.5℃; the frost-free period is 117-136 days; the average annual rainfall is 170 mm, mostly concentrated in summer and autumn. The soil pH value of the test field is 9.40±0.02, and the total water-soluble salt content is 3.65±0.20g / kg. The test field is a heavy saline-alkali soil. The field test area is 770m 2 The sunflower variety used for the test was Qianli No. 8, with a planting density of 1,200 plants / mu and covered with transparent plastic film. The experiment was divided into two planting modes: Mode 1: planting with substrate paper bags; Mode 2: using microbial agents to pretreat the soil + planting with substrate paper bags. The substrate paper bag mode used kraft paper bags with a diameter of 1.9 cm and a height of 15 cm ( Figure 7), filled with fully decomposed sheep manure as substrate soil to obtain a seedling pot, and sunflower seeds were planted into the pot at a sowing depth of 3 cm when sowing in the field. When sowing in the field, the substrate paper bag was manually planted into the field using a portable spot seeder, sown on July 5, 2024, and harvested in early October. The experiment was divided into 2 treatments, arranged in random blocks, and repeated 2 times.

[0054] Method for pretreating the soil in the test area using microbial agents: inoculate the frozen Bacillus megaterium TZ-1 into LB liquid culture medium and culture it at 28°C for 24 hours to obtain an activated strain; the composition of the LB liquid culture medium is as follows: 10 g / L tryptone, 5 g / L yeast extract, and 10 g / L sodium chloride; in addition, adjust the pH of the culture medium with NaOH according to the empirical value to 7.0, and sterilize at 121°C for 15 minutes. After centrifuging the activated strain, add an appropriate amount of sterilized water to prepare a bacterial suspension (the number of Bacillus megaterium is adjusted to 10 according to the hemocytometer method). 8 cfu / mL), and then the bacterial suspension was evenly mixed with 100g of inoculum (containing viable bacteria ≥ 5×10 9 CFU / g) / mu was sprayed to the soil depth of 0-20cm in the field soil. The field soil was plowed to a depth of 20cm in advance. After spraying the bacterial suspension, the soil was turned over and covered. One week later, sunflowers were planted. The depth of sunflower seeds in the seedling pot matrix soil was 3±0.2cm, the planting density was 1200 plants / mu, and transparent plastic film was covered before germination.

[0055] Test items (1) During the budding period of sunflowers, 10 sunflowers growing continuously were selected in the middle of each treatment group, and their plant height, stem thickness, leaf area, and SPAD value were measured. The specific measurement methods are as follows: the plant height was measured with a tape measure at the highest point of the sunflower disk above the ground; the stem thickness was measured with a vernier caliper at the base of the sunflower 5 cm above the ground; the leaf area was the 9th true leaf of the sunflower as the measurement object, and the leaf area was calculated according to the formula "leaf area (expanded) = 0.65 × length × width"; the SPAD value of the 9th true leaf of the sunflower was measured using a SPAD instrument. The measurement results are shown in Table 4 Group Plant height / cm Stem diameter / mm <![CDATA[Leaf area cm 2 > SPAD Mode 2 166 47 824.7 43.7 Mode 1 159 41 786.4 39.8

[0056] The experimental results show that when planting sunflowers in severe saline-alkali land, Mode 2 can significantly improve the plant height and leaf area of ​​sunflowers compared with Mode 1.

[0057] (2) Select appropriate sampling points, randomly select 20 sunflower plants in the sampling points, investigate the number of seeds per tray, and calculate the average value. After threshing, place the seeds in an oven at 105℃ for 30 minutes, dry them at 75℃ to constant weight, randomly select 1000 seeds, and weigh the thousand-grain weight. Yield (KG / mu) = number of plants per mu × number of seeds per plant × thousand-grain weight (g) × 10 -6 The measurement results are shown in Table 5. Seedling rate (%) Average 100-grain weight (g) Average number of grains per tray (grains) Empty shell and shrunken kernel rate (%) Yield (kg) / mu Mode 2 88.35 17.254 517.2 28.2 94.61 Mode 1 82.73 17.212 438.8 34.4 74.98

[0058] As shown in Table 5, the method of the present invention can be used to plant sunflowers in moderate saline-alkali land, which can effectively improve the emergence rate of sunflowers, reduce the rate of empty shells and shrunken grains, increase the number of seeds per tray, and thus significantly improve the yield per mu.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features therein may be replaced by equivalents. These modifications or replacements, or the technical features in the above embodiments may be combined in the manner described in the embodiments if they do not conflict with each other, and these modifications, replacements or combinations do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for planting sunflowers in severe saline-alkali land, characterized in that: include: The Bacillus megaterium with the deposit number of CGMCC NO.22296 was used. Bacillus megaterium ) TZ-1 biological agent was used to improve the field soil in the heavily saline-alkali land, and a long and narrow substrate bag filled with fully decomposed sheep manure was used as a seedling pot, and sunflower seeds were planted in the substrate soil of the seedling pot; The elongated matrix bag is a kraft paper bag with a diameter of 1.9±0.2 cm and a height of 15±1.0 cm. The sunflower seeds are inserted into the matrix soil of the seedling pot to a depth of 3±0.2 cm. When sowing in the field, the elongated matrix bag is planted in the field.

2. The method according to claim 1, characterized in that The landfill depth of the biological agent is in the range of 0-20 soil layer depth of field soil.

3. The method according to claim 2, characterized in that The planting density in the field is 1,200 plants per mu, and transparent plastic film is covered before seedlings emerge.

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