A saline-alkali stress solution and a coastal saline-alkali stress soil and application thereof

Abstract

This invention provides a salt-alkali stress solution and coastal salt-alkali stress soil, and their applications, belonging to the field of plant salt tolerance identification technology. The total mass concentration of the salt-alkali stress solution is 8-20 g / L, and the molar ratio of each component is NaCl:Na₂SO₄:MgSO₄:Na₂CO₃:KCl:CaCl₂ = 16:(6-12):(6-12):4:2:(0.1-3). The salt-alkali stress solution can also be further used to prepare coastal salt-alkali stress soil. By constructing a topsoil layer and drip-irrigating the salt-alkali stress solution, coastal salt-alkali stress soil can be created and maintained. This invention enables the convenient preparation of saline-alkali soil to simulate natural salt-alkali stress for field plant salt tolerance identification anytime and anywhere, even in natural environments where coastal saline-alkali soil is absent or lacking, achieving identification results consistent with natural salt-alkali stress environments.

Description

Technical Field

[0001] This invention belongs to the technical field of plant salt-alkali stress research, and particularly relates to a salt-alkali stress solution and coastal salt-alkali stress soil and their applications. Background Technology

[0002] The formation of saline-alkali soils follows the laws of water-salt transport. These soils contain a large amount of complex salts such as Na, K, Cl, SO4, SiO4, and various trace and micronutrients. As soil moisture rises, these complex salts accumulate in the topsoil, forming saline-alkali soil. Coastal saline-alkali soils are formed by seawater infiltration, are predominantly NaCl, and have a silty texture. However, through long-term natural evolution and human intervention, especially in coastal saline-alkali farmland where soil composition is more complex, other components such as K salts, Ca salts, SO4 salts, and even some trace elements interact with Na salts in coastal saline-alkali soils, resulting in very complex stresses on plants. Therefore, directly using seawater / artificial seawater or NaCl alone to assess crop salt tolerance is insufficient to reflect the actual salt tolerance of crops. The most direct and accurate method is to assess crop salt tolerance under natural saline-alkali soil conditions with relatively uniform soil salinity. However, such ideal natural environments are not readily available, and conducting crop salt tolerance assessments in areas lacking natural saline-alkali soil conditions presents a significant challenge.

[0003] The crux of the problem lies in how to simulate natural saline-alkali environments using artificial saline-alkali stress conditions and produce results consistent with those obtained under natural saline-alkali soil conditions. This requires consideration of two factors: first, a reasonable compound salt distribution formula, including determining the main components and their appropriate proportions; and second, how to use an artificial formula to prepare ideal saline-alkali soil. Only by combining these two aspects can results consistent with actual saline-alkali tolerance assessments be achieved.

[0004] Most existing salt tolerance assessment techniques are one-sided, primarily focusing on hydroponic conditions. These typically involve selecting a single salt, artificial seawater, or a compound salt, and employing hydroponic treatment or similar methods, such as over-irrigating with an aqueous solution based on a substrate like vermiculite or sand. Examples include CN201410821154.7 (a method for identifying salt tolerance in asparagus), CN202311701752.6 (a method for identifying salt and alkali tolerance in winter rapeseed), and CN201810610759.X (a method for identifying salt and alkali tolerance in industrial hemp seedlings). While these methods can assess crop (plant) salt and alkali tolerance to a certain extent, it's well known that hydroponic conditions differ from actual field soil conditions. Therefore, the consistency between hydroponic assessment results and natural field conditions is questionable, especially for salt and alkali tolerance assessment throughout the entire growth period. Consequently, the use of saline-alkali soils for assessing crop (plant) salt and alkali tolerance has been explored.

[0005] The second method for identifying salt and alkali tolerance involves using saline-alkali soil as the identification matrix, either directly utilizing the saline-alkali environment or mixing natural saline-alkali soil with ordinary soil. As mentioned earlier, using naturally occurring saline-alkali soil provides the most accurate data on crop salt tolerance in the field, as illustrated in CN202010731141.6 (Method for identifying wheat salt and alkali tolerance based on field growth tracing), CN202011194866.2 (A method for identifying soybean salt and alkali tolerance), and CN201710417148.9 (Breeding method for salt-alkali resistant edible sunflowers). However, the problem is that such ideal natural saline-alkali soil is not readily available. Therefore, most research or identification methods for plant salt and alkali tolerance involve directly irrigating the soil with artificial salt and alkali stress solutions. Examples include "The Effects of Salt Stress on the Physiological Characteristics of Different Salt-Tolerant Malus halliana Lines" and "The Effects of Three Types of Salt Stress on Wheat Seedling Growth." These methods do not consider whether the saline-alkali stress state created when saline-alkali solutions enter the soil is similar to that of saline-alkali soils under natural conditions, or whether the results are consistent with those obtained under natural conditions. One characteristic of coastal saline-alkali soils is their poor structure and high content of silty particles; therefore, direct watering easily leads to compaction, crusting, and localized waterlogging. The complex soil environment formed when stress ions in the solution combine with this soil condition differs from that of naturally occurring saline-alkali soils, and consequently, its impact on plants is also different.

[0006] In conclusion, to ensure the successful assessment of crop salt tolerance in the absence of ideal coastal saline-alkali soil environments, especially the assessment throughout the entire growth period in the field, it is essential to consider the main components of compound salts and the complex interactions between different ionic components and saline-alkali soils. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a salt-alkali stress solution and coastal salt-alkali stress soil and their application, which can conveniently prepare salt-alkali soil anytime and anywhere to simulate natural salt-alkali stress and conduct field salt-alkali tolerance assessment of crops under natural environmental conditions where there is no or a lack of coastal salt-alkali soil, and achieve the assessment effect consistent with the natural salt-alkali stress environment.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] A salt-alkali stress solution with a total mass concentration of 8-20 g / L and a molar ratio of NaCl:Na2SO4:MgSO4:Na2CO3:KCl:CaCl2 = 16:(6-12):(6-12):4:2:(0.1-3).

[0010] The present invention also provides the application of the aforementioned salt-alkali stress solution in the identification of plant salt-alkali tolerance and its application in the preparation of coastal salt-alkali stress soil.

[0011] Another objective of this invention is to provide a method for preparing coastal saline-alkali stress soil, constructing a topsoil layer, and creating and maintaining coastal saline-alkali stress soil by drip irrigation of the saline-alkali stress solution.

[0012] The creation requirement is that the salt content in the effective tillage layer of the soil reaches a set value after 2-4 drip irrigations. Each drip irrigation starts when the relative moisture content of the effective tillage layer is ≤13% in the 0-10cm layer, ≤14% in the 10-20cm layer, and ≤15% in the 20cm-40cm layer, and ends when the relative moisture content of the 0-10cm layer is ≤18%, ≤17% in the 10-20cm layer, and ≤16% in the 20cm-40cm layer.

[0013] The requirement is to start drip irrigation after the salt content in the effective tillage layer of the soil is 0.1-0.2 percentage points lower than the set value, and continue until the salt content recovers to the set value. After drip irrigation, the relative moisture content of the effective tillage layer is ≤18% for the 0-10cm layer, ≤17% for the 10-20cm layer, and ≤16% for the 20cm-40cm layer.

[0014] Preferably, the average soil bulk density of the constructed topsoil is 1.3-1.5 g / cm³. 3 The construction method includes: filling soil in 10-20cm layers and then compacting it. The compacted bottom soil has a bulk density of 1.4-1.5g / cm³. 3 The density gradually decreases until the top 10cm soil layer has a bulk density of 1.1g / cm³. 3 .

[0015] Preferably, the effective depth of the topsoil for salinity stress is 20-40 cm.

[0016] Preferably, the creation process also includes an initial drip irrigation volume of 10-15 mg / L of salt-alkali stress solution. 3 / mu, followed by drip irrigation of 6-10m each time. 3 / acre, with a difference of 4-7 days between each drip irrigation.

[0017] Preferably, the maintenance also includes a drip irrigation volume of 6-10m³ per drip. 3 / mu, the concentration of the salt-alkali stress solution is 2-3 times the set soil salinity, and drip irrigation is carried out 1-2 times every 4-7 days.

[0018] The present invention also provides coastal saline-alkali stress soil obtained by the method of preparing coastal saline-alkali stress soil and its application in the identification of plant salt tolerance.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] This invention provides a salt-alkali stress solution and coastal salt-alkali stress soil, which can be conveniently prepared anytime and anywhere to simulate natural salt-alkali stress and conduct field salt-alkali tolerance assessment of crops under natural environmental conditions where there is no or a lack of coastal salt-alkali soil, and achieve the same assessment effect as the natural salt-alkali stress environment.

[0021] The components of the salt-alkali stress solution formulation of this invention are consistent with the main stress components in coastal saline-alkali soil. During the optimization and adjustment process, the interaction between ions in the soil was taken into consideration, making the proportion of each component more scientific and reasonable. It can be further formulated to simulate the natural coastal saline-alkali soil environment for field salt-alkali tolerance identification of plants.

[0022] This invention not only solves the problem of how to simulate the natural saline-alkali environment using artificial saline-alkali stress conditions in areas lacking natural coastal saline-alkali land conditions and produce identification results consistent with those under natural saline-alkali land conditions, but can also be extended to the identification of hydroponic conditions. Attached Figure Description

[0023] Figure 1 Cl samples from soil and groundwater in coastal saline-alkali areas - Standard molar quantity distribution;

[0024] Figure 2 SO4 content of soil and groundwater samples from coastal saline-alkali areas 2- Standard molar quantity distribution;

[0025] Figure 3 CO3 samples from soil and groundwater in coastal saline-alkali areas 2- and HCO3 - Standard molar quantity distribution;

[0026] Figure 4 Na from soil and groundwater samples in coastal saline-alkali areas + Standard molar quantity distribution;

[0027] Figure 5 K, soil and groundwater samples from coastal saline-alkali areas + Standard molar quantity distribution;

[0028] Figure 6 Ca from soil and groundwater samples in coastal saline-alkali areas 2+ Standard molar quantity distribution;

[0029] Figure 7 Mg from soil and groundwater samples in coastal saline-alkali areas 2+ Standard molar quantity distribution. Detailed Implementation

[0030] This invention provides a salt-alkali stress solution with a total mass concentration of 8-20 g / L. The molar ratio of each component is NaCl:Na₂SO₄:MgSO₄:Na₂CO₃:KCl:CaCl₂ = 16:(6-12):(6-12):4:2:(0.1-3), preferably NaCl:Na₂SO₄:MgSO₄:Na₂CO₃:KCl:CaCl₂ = 16:9:9:4:2:1. The molar ratio of each component in this invention is consistent with the main stress components in coastal saline-alkali soils. The optimization and adjustment process takes into account the interactions between ions in the soil, making the component ratio more scientific and reasonable. This invention also provides the application of the salt-alkali stress solution in the preparation of coastal saline-alkali stress soils, which can be further used to prepare coastal saline-alkali soils to simulate the natural coastal saline-alkali soil environment for field salt-alkali tolerance assessment of plants. The plants mentioned in this invention are preferably crops, including but not limited to food crops, cash crops, and oil crops.

[0031] This invention also provides the application of the aforementioned salt-alkali stress solution in the identification of plant salt-alkali tolerance, which can be extended to the identification of hydroponic conditions.

[0032] This invention also provides a method for preparing coastal saline-alkali stress soil, comprising the following steps: (1) constructing a topsoil layer, (2) creating coastal saline-alkali stress soil, and (4) maintaining coastal saline-alkali stress soil. Based on a saline-alkali stress solution formulation and this saline-alkali soil preparation method, this invention can promote the formation of an effective saline-alkali stress zone in the topsoil layer during crop field testing and ensure that the soil salinity content remains stably within a set range. Especially in step (2), the soil stress environment creation stage, because it involves multiple small-volume drip irrigation, the original soil structure is not damaged. The resulting topsoil structure is closer to that of saline-alkali soil in a natural environment, and will not cause soil compaction, peeling, or localized waterlogging due to a single direct irrigation. Furthermore, because it is intermittent drip irrigation, it can effectively retain the required salt content within the effective topsoil layer, preventing some salt from leaching outside the effective topsoil layer due to excessive irrigation, thus achieving a certain cost-saving effect. The underlying principle is to fully utilize the water-salt transport patterns. After the initial small-scale drip irrigation, as the water evaporates, the salt that seeps down from the drip irrigation returns to the effective topsoil layer with the rising water level. Through repeated drip irrigation and the up-and-down movement of water, the desired soil salinity is eventually achieved within the effective topsoil layer. This process is consistent with the formation of naturally occurring saline-alkali soils. These combined effects ensure that the results of plant salt tolerance assessments are consistent with those obtained under natural saline-alkali stress environments.

[0033] Step (1) includes: [The following text appears to be incomplete and requires further context: "according to an average soil bulk density of 1.3-1.5 g / cm³..."] 3Prepare an appropriate amount of soil, and then fill it in layers according to the soil bulk density of the corresponding soil layer in the coastal saline-alkali land; specifically, fill each 10-20cm layer with soil and then compact it. The compacted bottom layer soil bulk density is 1.4-1.5g / cm³. 3 The density gradually decreases until the top 10cm soil layer has a bulk density of 1.1g / cm³. 3 Preferably, the surface of the soil layer is roughened before filling the next soil layer. Further preferred embodiments of the present invention include: when the crop is identified as a shallow-rooted crop, the depth of the topsoil layer is 30-40 cm; when the crop is identified as a deep-rooted crop, the depth of the topsoil layer is 50-60 cm.

[0034] The present invention preferably uses a topsoil salinity stress effective depth of 20-40cm, and more preferably 20cm for shallow-rooted crops and 30-40cm for deep-rooted crops. This effective depth is used as the range for salinity detection in saline-alkali soil.

[0035] Step (2) includes: the number of drip irrigations and the interval, the concentration of the salt-alkali stress solution, and the drip irrigation volume. These depend on the target soil salinity (%) and relative soil moisture (%) within the effective tillage depth. Specifically, the salt content (%) within the effective tillage depth should reach the set value after 2-4 drip irrigations (the final average salt content error of the effective tillage layer should be within 0.1 percentage points). Each drip irrigation starts when the relative moisture content of the 0-10cm layer is ≤13%, the 10-20cm layer is ≤14%, and the 20cm-40cm layer is ≤15%, and ends when the relative moisture content of the 0-10cm layer is ≤18%, the 10-20cm layer is ≤17%, and the 20cm-40cm layer is ≤16%. The preferred drip irrigation volume for the first drip irrigation of the salt-alkali stress solution is 10-15m³. 3 / mu, followed by drip irrigation of 6-10m each time. 3 The drip irrigation frequency is 4-7 days between each application. Further optimization involves calculating the required salt-stress solution dosage for the corresponding field assessment scale based on the drip irrigation volume. The concentration of the salt-stress solution for the first drip irrigation is set at 8-15 g / L, referencing the target soil salinity. Subsequent applications involve appropriately increasing the concentration of the salt-stress solution based on the effective topsoil salinity, until the final effective topsoil salinity reaches the target value. As one possible implementation method, the drip irrigation frequency is adjusted according to the actual climate conditions. For example, in dry climates with high evaporation, drip irrigation can be repeated after 4-5 days; if the weather is average, it can be repeated after 6-7 days.

[0036] Step (3) includes: starting drip irrigation after the salt content (%) in the effective tillage layer of the soil is 0.1-0.2 percentage points lower than the set value, and continuing until the salt content recovers to the set value (the final average salt content error in the effective tillage layer should be within 0.1 percentage points). After drip irrigation, the relative moisture content of the 0-10cm layer of the effective tillage layer should be ≤18%, the relative moisture content of the 10-20cm layer should be ≤17%, and the relative moisture content of the 20cm-40cm layer should be ≤16%. The preferred drip irrigation volume is 6-10m³ per irrigation. 3 / mu, the concentration of the salt-alkali stress solution is 2-3 times the set soil salinity, and drip irrigation is carried out 1-2 times every 4-7 days; further optimization is carried out by testing every 2-4 weeks.

[0037] The present invention also provides coastal saline-alkali stress soil obtained by the method of preparing coastal saline-alkali stress soil and its application in the identification of plant salt tolerance. Preferably, if plants have already been planted, the drip irrigation pipe is placed in the middle of the ridge (row) rather than directly in front of the crop roots.

[0038] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1

[0040] A salt-alkali stress solution with a total mass concentration of 20 g / L and a molar ratio of NaCl:Na2SO4:MgSO4:Na2CO3:KCl:CaCl2 = 16:9:9:4:2:1 is prepared by weighing and dissolving the components in water according to the ratio.

[0041] Example 2

[0042] A salt-alkali stress solution has a total mass concentration of 15 g / L and the molar ratio of its components is NaCl:Na2SO4:MgSO4:Na2CO3:KCl:CaCl2 = 16:6:12:4:2:0.5. The solution is prepared by weighing and dissolving the components in water according to the specified ratio.

[0043] Example 3

[0044] A salt-alkali stress solution has a total mass concentration of 8 g / L and the molar ratio of its components is NaCl:Na2SO4:MgSO4:Na2CO3:KCl:CaCl2 = 16:12:6:4:2:3. It is prepared by weighing and dissolving the components in water according to the specified ratio.

[0045] Example 4

[0046] A coastal saline-alkali stress soil, the preparation method is as follows:

[0047] (1) Constructing the topsoil:

[0048] (1.1) Set the scale for crop field identification (m) 2 Based on an average soil bulk density of 1.3 g / cm³ 3 Prepare an appropriate amount of soil, with a depth of 30-40cm for shallow-rooted crops and 50-60cm for deep-rooted crops. Then, fill the soil in layers according to the corresponding soil bulk density of the coastal saline-alkali land. Specifically, fill the soil in 15cm layers and then compact it. The compacted bottom layer of soil should have a bulk density of 1.5g / cm³. 3 Then the bulk density gradually decreases until it reaches 1.1 g / cm³ in the topsoil layer (0-10 cm). 3 Before filling the next soil layer, roughen the surface of the soil layer;

[0049] (1.2) The effective depth of topsoil salinity stress is set at 20-40cm, of which the effective depth of topsoil salinity stress is 20cm for shallow-rooted crops and 30-40cm for deep-rooted crops.

[0050] (2) Creation of coastal saline-alkali stress soils:

[0051] When using drip irrigation, pay special attention if crops have already been planted. Place the drip irrigation pipe in the middle of the row (ridge) rather than directly at the crop roots. Three drip irrigations are required, with the first irrigation volume being 12.5m³. 3 / mu, followed by each drip irrigation at a rate of 8m³. 3 Calculate the required amount of salt-alkali stress solution for the corresponding field assessment scale based on the drip irrigation volume; set the concentration of salt-alkali stress solution between 8-20 g / L for each drip irrigation. The concentration of salt-alkali stress solution for the first drip irrigation can be set between 8-15 g / L with reference to the target soil salinity. The concentration of salt-alkali stress solution for subsequent drip irrigations can be appropriately increased according to the effective topsoil salinity, until the final effective topsoil salinity reaches the target value. The drip irrigation time should be 5 days apart.

[0052] Soil salinity and moisture content were sampled and tested before and after each drip irrigation. Soil salinity was required to gradually increase within the effective topsoil layer after three drip irrigations, eventually reaching the target value. The final average salinity percentage (%) in the effective topsoil layer should have an error within 0.1 percentage points. Soil moisture was tested after each drip irrigation based on the effective depth of the topsoil under salinity stress. The relative moisture content was required to be ≤18% for the 0-10cm layer, ≤17% for the 10-20cm layer, and ≤16% for the 20cm-40cm layer. Subsequently, before each drip irrigation, the relative moisture content was tested to be ≤13% for the 0-10cm layer, ≤14% for the 10-20cm layer, and ≤15% for the 20cm-40cm layer.

[0053] (3) Maintenance of coastal saline-alkali stressed soils:

[0054] After the formation of a saline-alkali stress environment in the topsoil, a saline-alkali stress solution is drip-irrigated periodically to ensure that the soil salinity within the effective saline stress depth range of the topsoil matches the set soil salinity during the crop salinity tolerance assessment period; each drip irrigation is 8m³. 3 / mu, the concentration of the salt-alkali stress solution should be 2-3 times the set soil salinity content; specifically, the average soil salinity content (%) of the effective topsoil layer should be tested every 3 weeks. Drip irrigation should begin when the soil salinity content is 0.1 percentage points lower than the target soil salinity, and drip irrigation should be carried out 1-2 times every 4-7 days. After drip irrigation, the average soil salinity content should reach the target value, and the final average salinity content error of the effective topsoil layer should be within 0.1 percentage points; after drip irrigation, the relative moisture content (%) of the topsoil layer should be ≤18% for the 0-10cm layer, ≤17% for the 10-20cm layer, and ≤16% for the 20cm-40cm layer.

[0055] Example 5

[0056] A coastal saline-alkali stress soil, the preparation method is as follows:

[0057] (1) Constructing the topsoil:

[0058] (1.1) Set the scale for crop field identification (m) 2 Based on an average soil bulk density of 1.3 g / cm³ 3 Prepare an appropriate amount of soil, with a depth of 30-40cm for shallow-rooted crops and 50-60cm for deep-rooted crops. Then, fill the soil in layers according to the corresponding soil bulk density of the coastal saline-alkali land. Specifically, fill the soil in 10cm layers and then compact it. The compacted bottom layer of soil should have a bulk density of 1.4g / cm³. 3 Then the bulk density gradually decreases until it reaches 1.1 g / cm³ in the topsoil layer (0-10 cm). 3 Before filling the next soil layer, roughen the surface of the soil layer;

[0059] (1.2) Same as Example 4;

[0060] (2) Creation of coastal saline-alkali stress soils:

[0061] When using drip irrigation, pay special attention if crops have already been planted. Place the drip irrigation tubing in the middle of the row (ridge) rather than directly at the crop roots. Two drip irrigations are required; the first drip irrigation should be 15m³. 3 / mu, the second drip irrigation volume is 10m 3 / mu, calculate the amount of salt-alkali stress solution required for the corresponding field identification scale based on the drip irrigation volume; the concentration of salt-alkali stress solution for each drip irrigation is set between 8-20g / L, of which the concentration of salt-alkali stress solution for the first drip irrigation can be set between 8-15g / L with reference to the target soil salinity content, and the concentration of salt-alkali stress solution for subsequent drip irrigations can be appropriately increased according to the effective topsoil salinity content, until the final effective topsoil salinity content reaches the target value, with each drip irrigation time differing by 7 days;

[0062] Soil salinity and moisture content were sampled and tested before and after each drip irrigation. Soil salinity was required to gradually increase within the effective topsoil layer after two drip irrigations, eventually reaching the target value. The final average salinity percentage (%) in the effective topsoil layer should have an error within 0.1 percentage points. Soil moisture was tested after each drip irrigation based on the effective depth of the topsoil under salinity stress. The relative moisture content was required to be ≤18% for the 0-10cm layer, ≤17% for the 10-20cm layer, and ≤16% for the 20-40cm layer. Subsequently, before each drip irrigation, the relative moisture content was tested: ≤13% for the 0-10cm layer, ≤14% for the 10-20cm layer, and ≤15% for the 20-40cm layer.

[0063] (3) Maintenance of coastal saline-alkali stressed soils:

[0064] Each drip irrigation volume is 10m. 3 / mu, the concentration of the salt-alkali stress solution should be 2-3 times the set soil salinity content; specifically, the average soil salinity content (%) of the effective topsoil layer should be tested every 4 weeks. Drip irrigation should begin when the soil salinity content is 0.2 percentage points lower than the target soil salinity, and drip irrigation should be carried out 1-2 times every 4-7 days. After drip irrigation, the average soil salinity content should reach the target value, and the final average salinity content error of the effective topsoil layer should be within 0.1 percentage points; after drip irrigation, the relative moisture content (%) of the topsoil layer should be ≤18% for the 0-10cm layer, ≤17% for the 10-20cm layer, and ≤16% for the 20cm-40cm layer.

[0065] Example 6

[0066] A coastal saline-alkali stress soil, the preparation method is as follows:

[0067] (1) Constructing the topsoil:

[0068] (1.1) Set the scale for crop field identification (m) 2 Based on an average soil bulk density of 1.4 g / cm³ 3Prepare an appropriate amount of soil, with a depth of 30-40cm for shallow-rooted crops and 50-60cm for deep-rooted crops. Then, fill the soil in layers according to the corresponding soil bulk density of the coastal saline-alkali land. Specifically, fill the soil in 20cm layers and then compact it. The compacted bottom layer should have a bulk density of 1.5g / cm³. 3 Then the bulk density gradually decreases until it reaches 1.1 g / cm³ in the topsoil layer (0-10 cm). 3 Before filling the next soil layer, roughen the surface of the soil layer;

[0069] (1.2) Same as Example 4;

[0070] (2) Creation of coastal saline-alkali stress soils:

[0071] When using drip irrigation, pay special attention to placing the drip irrigation pipe in the middle of the row (ridge) rather than directly at the crop roots if crops have already been planted. Four drip irrigations are required, with the first irrigation volume being 10m³. 3 / mu, followed by drip irrigation of 6m³ each time. 3 / mu, calculate the amount of salt-alkali stress solution required for the corresponding field identification scale based on the drip irrigation volume; the concentration of salt-alkali stress solution is set between 8-20g / L for each drip irrigation, and the concentration of salt-alkali stress solution for the first drip irrigation can be set between 8-15g / L with reference to the target soil salinity content. The concentration of salt-alkali stress solution for subsequent drip irrigations can be appropriately increased according to the effective topsoil salinity content until the final effective topsoil salinity content reaches the target value. The drip irrigation time is 4 days apart.

[0072] Soil salinity and moisture content were sampled and tested before and after each drip irrigation. Soil salinity was required to gradually increase within the effective topsoil layer after four drip irrigations, eventually reaching the target value. The final average salinity percentage (%) in the effective topsoil layer should have an error within 0.1 percentage points. Soil moisture was tested after each drip irrigation, based on the effective depth of the topsoil under salinity stress. The relative moisture content was required to be ≤18% for the 0-10cm layer, ≤17% for the 10-20cm layer, and ≤16% for the 20-40cm layer. Subsequently, before each drip irrigation, the relative moisture content was tested: ≤13% for the 0-10cm layer, ≤14% for the 10-20cm layer, and ≤15% for the 20-40cm layer.

[0073] (3) Maintenance of coastal saline-alkali stressed soils:

[0074] Each drip irrigation volume is 6m 3 / mu, the concentration of the salt-alkali stress solution should be 2-3 times the set soil salinity content; specifically, the average soil salinity content (%) of the effective topsoil layer should be tested every 2 weeks. Drip irrigation should begin when the soil salinity content is 0.15 percentage points lower than the target soil salinity, and drip irrigation should be carried out 1-2 times every 4-7 days. After drip irrigation, the average soil salinity content should reach the target value, and the final average salinity content error of the effective topsoil layer should be within 0.1 percentage points; after drip irrigation, the relative moisture content (%) of the topsoil layer should be ≤18% for the 0-10cm layer, ≤17% for the 10-20cm layer, and ≤16% for the 20cm-40cm layer.

[0075] Example 7

[0076] Determination of the main components of salt-alkali stress solution

[0077] In April and October 2023, soil samples (0-20cm and 20-40cm) and local groundwater were collected in typical coastal saline-alkali areas of Hebei Province, including Caofeidian District and Leting County of Tangshan City and Yanshan County of Cangzhou City, for a total of 270 samples.

[0078] First, the total salt content (%) was determined using the drying method; then, the content of eight major ions (mg / kg), including Na+, was determined using atomic absorption spectrometry and titration. + K + Ca 2+ Mg 2+ Cl - HCO3 - CO3 2- and SO4 2- Next, the contents of the eight major ions in each sample were standardized using the following conversion formula: M = A * S0 / S1, where M represents the standardized content (mg / kg) of each ion in each sample, A represents the content of each ion in each sample (mg / kg), S0 represents the average salt content (%) of all samples, and S1 represents the salt content (%) of each sample. Then, the standardized content of each ion in each sample was converted into the corresponding molar amount (mmol) based on the corresponding molecular weight. Finally, statistical analysis was performed using SPSS or Excel software. The results are shown in Table 1 and the frequency distribution. Figure 1-7 .

[0079] Table 1. Distribution of standard molar amounts (mmol) of eight ions in soil and groundwater samples from coastal saline-alkali areas.

[0080] Minimum value Maximum value median average value coefficient of variation <![CDATA[HCO3 - +CO3 2- ]]> 0.197 11.229 2.128 2.573 2.138 <![CDATA[Cl - ]]> 0.333 61.520 11.656 19.205 19.035 <![CDATA[SO4 2- ]]> 0.901 31.875 11.284 11.687 8.334 <![CDATA[Ca 2+ ]]> 0.099 38.657 8.279 10.662 9.532 <![CDATA[Mg 2+ ]]> 0.360 9.776 5.405 5.332 2.866 <![CDATA[K + ]]> 0.089 32.404 1.222 7.613 9.733 <![CDATA[Na + ]]> 1.619 114.085 25.565 38.545 31.528 Salt content (%) 0.065 3.850 0.229 0.513 0.730

[0081] As shown in Table 1 and Figure 1-7 As shown in the figure, the Na+ content of soil in coastal saline-alkali areas is relatively high.+ Cl - and SO4 2- It is mostly composed of major ionic components, while K + The content is the lowest, with the main ionic components accounting for 72.79% of the total soil salt content, consistent with the characteristics of coastal saline-alkali soils. In reality, the adverse effects of saline-alkali soils on plants are due to physiological drought caused by excessively high concentrations of salts such as NaCl and Na₂SO₄. Simultaneously, excessively high Na ion concentrations also make the soil heavier and more restrictive of plant growth. HCO₃⁻ - / CO3 2- Excessive levels of these ions are a major cause of soil alkalinity; increased pH also affects plant water absorption and limits the absorption of other elements. Other ions, such as Ca... 2+ Mg 2+ and K + K is a nutrient element that promotes plant growth and development and can react with Na. + Interactions mitigate the effects of salt damage; appropriate amounts of Ca 2+ and Mg 2+ It is also an important element for plant growth and development, but excessively high concentrations can cause osmotic stress. In short, Ca... 2+ Mg 2+ and K + In saline-alkali soils, it plays a regulating role; therefore, the impact of saline-alkali land on plants is not caused by a single salt, but by the complex interaction of multiple salts. In this invention, Na₂CO₃ is used instead of NaHCO₃. From a chemical perspective, this is because CO₃²⁻... 2- It will slowly convert into HCO3 - Furthermore, Na2CO3 is more alkaline. Additionally, a high concentration of Ca ions was detected in the soil samples, possibly due to the high Ca ion content inherent in the soil itself, which is related to the parent material. However, excessive Ca ions in the formulation can lead to precipitation; therefore, the Ca ion content was reduced in this invention.

[0082] Finally, based on the median in Table 1 and the chemical formulas, the main components of the saline-alkali solution formulation can be determined to be: NaCl, Na₂SO₄, MgSO₄, Na₂CO₃, KCl, and CaCl₂. Combining the frequency distribution of each ion, the approximate range of the molar amounts (mmol) of each component can be preliminarily determined as follows:

[0083] NaCl: 4.0-9.0;

[0084] Na2SO4: 1.0-5.0;

[0085] MgSO4: 2.0-10.0;

[0086] Na2CO3: 1.0-5.0;

[0087] KCl: 1.0-3.0;

[0088] CaCl2: 0.0-2.5.

[0089] Example 8

[0090] Optimization scheme for salt-alkali stress solution formulation

[0091] 1. Optimization Scheme 1 - Na2SO4

[0092] The experiment was conducted inside a ventilated and rainproof shed at an experimental base of the Coastal Agriculture Research Institute of the Hebei Academy of Agricultural and Forestry Sciences.

[0093] A strategy was adopted to fix the molar ratio of NaCl, Na2CO3, and KCl, i.e., NaCl:Na2CO3:KCl = 8:2:1, and adjust the ratio of other components. The ratio of these three components was determined by the survey results of the content of each component in the soil sample, as detailed in Example 7.

[0094] First, a salt-alkali stress solution was prepared. The molar ratio of Na₂SO₄ in the solution was set into five groups according to the results in Example 1: 3, 6, 9, 12, and 15. The remaining components were prepared with a molar ratio of NaCl:MgSO₄:Na₂CO₃:KCl:CaCl₂ = 16:9:4:2:1, with a total mass concentration of 20 g / L. The purpose was to compare the optimal range of target components under the conditions of interaction between various ions in the soil with a fixed total salt content. The salt-alkali stress solution was diluted as needed before use. Then, large flowerpots (25 cm in diameter, 45 cm deep) and local ordinary soil were prepared. After drip irrigation three times according to the saline-alkali soil preparation method described in Example 4, the average salt content of the 40 cm topsoil layer was 0.49%. After the saline-alkali soil was prepared, five varieties of corn were planted, with five pots of each variety and three seedlings per pot. In the second and fourth weeks after planting the corn, seedlings were planted at 6 m... 3 The soil was supplemented with a salt-alkali stress solution at a rate of 15 g / L per mu (approximately 0.067 hectares) through drip irrigation. The average soil salinity was 0.52% throughout the experimental period. The experiment included a treatment group, a control group, and a field group. The treatment group consisted of potted plants in saline-alkali soil, the control group consisted of potted plants in lightly soil, and the field group consisted of a natural 3m x 5m saline-alkali plot within the experimental site with an average salinity of 0.53% and a pH of 8.3. On day 35 after sowing, the ratios of the treatment group and the field group to the control group were calculated based on the average plant height of the maize. The fields were then sorted by their ratios. The results of the maize salt-alkali tolerance evaluation are shown in Table 2.

[0095] Table 2 Comparison of salt and alkali tolerance of maize after Na2SO4 optimization and adjustment.

[0096]

[0097]

[0098] Note: P-values ​​are the p-values ​​of one-way ANOVA between each treatment group and the field group. The larger the value, the smaller the difference between groups. The same applies below.

[0099] As shown in Table 2, increasing the Na₂SO₄ content exacerbates salt stress. Overall, the ranking of the five maize varieties is consistent; however, when the molar proportion of Na₂SO₄ exceeds 12 or falls below 6, the ranking of salt tolerance among the five maize varieties differs from the field assessment results. The ranking is closest when the molar proportion of Na₂SO₄ is 9, with a p-value of 0.972. Therefore, the suitable molar proportion of Na₂SO₄ is between 6 and 12, with the optimal molar proportion being 9.

[0100] 2. Optimized scheme 2-MgSO4

[0101] Five groups were established for the salt-alkali stress solution formulation, with the molar ratio of MgSO4 as shown in Example 7: 3, 6, 9, 12, and 15. The remaining components were prepared in a molar ratio of NaCl:Na₂SO₄:Na₂CO₃:KCl:CaCl₂ = 16:9:4:2:1, with a total mass concentration of 20 g / L. All other treatment methods were the same as in optimization scheme 1. The results of the salt-alkali tolerance evaluation of maize are shown in Table 3.

[0102] Table 3 Comparison of salt and alkali tolerance of maize after MgSO4 optimization.

[0103]

[0104] Table 3 shows that increasing the MgSO4 content in the soil within a moderate range can alleviate salt-alkali stress to some extent. Overall, the ranking of the five maize varieties is consistent; however, when the molar proportion of MgSO4 exceeds 12 or falls below 6, the ranking of salt-alkali tolerance among the five maize varieties differs from the field evaluation results. The ranking is closest when the molar proportion of MgSO4 is 9, with a P-value of 0.998. Therefore, the suitable molar proportion of MgSO4 is between 6 and 12, with the optimal molar proportion being 9.

[0105] 3. Optimized scheme 3-CaCl2

[0106] Five groups were established for the molar ratio of CaCl2 in the salt-alkali stress solution formulation, based on the results in Example 7: 0.1, 0.5, 1, 3, and 5. The remaining components were prepared in a molar ratio of NaCl:Na₂SO₄:MgSO₄:Na₂CO₃:KCl = 16:9:9:4:2, with a total mass concentration of 20 g / L. All other treatment methods were the same as in optimization scheme 1. The results of the salt-alkali tolerance evaluation of maize are shown in Table 4.

[0107] Table 4 Comparison of salt and alkali tolerance of maize after CaCl2 optimization.

[0108]

[0109] Table 4 shows that appropriately increasing the CaCl2 concentration can alleviate salt stress damage to plants. Overall, the ranking of the five maize varieties is consistent; however, when the molar proportion of CaCl2 exceeds 3, the ranking of salt tolerance among the five maize varieties differs from the field assessment results. The ranking is closest when the molar proportion of CaCl2 is 1 (P = 0.987). Therefore, the suitable molar proportion of CaCl2 is between 0.1 and 3, with the optimal molar proportion being 1.

[0110] Based on the results of combined optimization schemes 1-3, the formulation of the salt-alkali stress solution can be derived as follows:

[0111] NaCl: 16;

[0112] Na2CO3:4;

[0113] KCl:2;

[0114] MgSO4: 6-12;

[0115] Na2SO4: 6-12;

[0116] CaCl2: 0.1-3.

[0117] The optimal molar ratio is NaCl:Na2SO4:MgSO4:Na2CO3:KCl:CaCl2 = 16:9:9:4:2:1.

[0118] Example 9

[0119] Creation of coastal saline-alkali soil

[0120] The experiment was conducted in a ventilated and rainproof shed at the Experimental Base of the Coastal Agriculture Research Institute of the Hebei Academy of Agricultural and Forestry Sciences. Soil was filled into a 5m x 3m x 0.6m cement pool using the "(1) Construction of Topsoil" method described in Example 4. After filling, the relative soil moisture content was 7.8%, and the soil salinity was 0.08%. Drip irrigation was used. The irrigation volume and salt-alkali stress solution concentration are shown in Table 5. The salt-alkali stress solution was prepared according to the optimal formula, i.e., the molar ratio of each component NaCl:Na2SO4:MgSO4:Na2CO3:KCl:CaCl2=16:9:9:4:2:1. The total mass concentration of the prepared solution was 20g / L, and it was diluted as needed before use. The soil salinity and relative moisture content of each layer were measured after the experiment, and the results are shown in Table 6.

[0121] Table 5. Drip Irrigation Control of Salt-Alkali Stress Solution

[0122] first The second The third Fourth Interval days - 4 7 7 <![CDATA[Drip irrigation amount (m 3 / mu)]]> 15 10 8 6 Total concentration of solution (g / L) 8 15 20 20

[0123] Table 6. Test results after mixing saline-alkali soil.

[0124]

[0125] Note: In the table, SR represents soil salinity (%), RWR1 represents soil relative moisture content (%) after drip irrigation, RWR2 represents soil relative moisture content (%) before drip irrigation, and 0-40cm represents soil samples from each soil layer.

[0126] As shown in Table 6, the water content of different soil layers tended to be uniform after the second drip irrigation; the salt content also gradually accumulated and increased in different soil layers. Based on this result, it can be predicted that after the saline-alkali soil conditions are established, during the later periodic stress soil environment maintenance stage, the salt content in the deeper soil layers will also accumulate and increase, eventually achieving a stable salt distribution throughout the entire topsoil layer. According to the results in Table 6, if the target soil salt content is set at 0.2%-0.3%, two drip irrigations are required; if the target soil salt content is set at 0.4%-0.5%, three drip irrigations are required; and if the target soil salt content is set at 0.6%-0.7%, four drip irrigations are required.

[0127] Example 10

[0128] Maize Field Salt-Alkali Tolerance Identification Test

[0129] The experiment was conducted in a ventilated and rainproof shed at an experimental base of the Binhai Agriculture Research Institute of the Hebei Academy of Agricultural and Forestry Sciences. Following the method in Example 4, ordinary light soil was filled into a 5m x 3m x 0.6m cement-filled shed. After filling, the relative soil moisture content was measured at 7.8%, and the soil salinity was 0.08%, with a target salinity of 0.5%. After preparing a salt-alkali stress solution according to the method in Example 9 and applying it via drip irrigation three times, the average salinity of the 40cm topsoil layer was 0.49%. Subsequently, ten varieties of maize were planted, sown in hills with two seeds per hill, with a row spacing of 50cm and a hill spacing of 30cm. The experiment lasted 35 days. In the second and fourth weeks after planting, seeds were sown at 10m intervals. 3 The soil was supplemented with a salt-alkali stress solution at a rate of 15 g / L per mu (approximately 0.067 hectares) through drip irrigation. The average soil salinity was 0.53% throughout the experimental period. The treatment group was a saline-alkali soil cement pond, the control group was a light soil cement pond, and the field group was a natural 3m x 5m saline-alkali plot within the experimental site, with an average salinity of 0.53% and a pH of 8.3. After the experiment, the average plant height of maize was recorded, and the ratios of the treatment group and field group to the control group were calculated. The fields were sorted by their respective ratios. The results of the maize salt-alkali tolerance evaluation are shown in Table 7.

[0130] Table 7 Results of salt and alkali tolerance assessment of maize in the field

[0131] variety CK group Processing group Field group Ratio 1 Ratio 2 Sort Jingke 968 23.6±2.9 22.4±1.6 22.5±1.7 0.950 0.955 1 Jingke 665 25.1±2.3 22.0±1.8 22.2±1.8 0.875 0.883 2 Zhengdan 958 26.1±3.2 21.2±2.3 20.8±2.7 0.811 0.798 3 Nonghua 101 32.0±3.0 25.4±2.2 25.3±2.6 0.792 0.788 4 Jundan 20 27.6±3.4 21.7±2.3 21.7±2.4 0.787 0.786 5 Agricultural University 108 27.8±3.3 21.8±2.4 21.6±1.4 0.785 0.779 6 Xianyu 335 25.4±2.9 19.5±2.5 19.6±2.6 0.769 0.774 7 Jingdan 38 26.3±2.1 18.8±2.1 18.8±2.7 0.713 0.714 8 NK815 29.5±2.8 21.1±1.8 20.7±2.5 0.715 0.700 9 Jingnongke 728 31.6±3.3 18.1±2.3 18.1±1.7 0.573 0.572 10

[0132] Note: The data in the table represent the average plant height of maize (cm). Ratio 1 is the treatment group / CK group, and ratio 2 is the field group / CK group.

[0133] As shown in Table 7, the relative plant height of maize obtained from the identification is close to that of the field group, and the ranking of the salt and alkali tolerance results of the 10 maize varieties is consistent with the field identification results. This indicates that the saline-alkali soil of the present invention can be used for the salt and alkali tolerance identification of deep-rooted crops (maize), which can replace the natural saline-alkali land stress environment and achieve the same effect as the identification results of natural saline-alkali land conditions.

[0134] Example 11

[0135] Salt and alkali tolerance identification test of triticale in the field

[0136] Following the method described in Example 10, a 5m x 3m x 0.6m cement bed was prepared with lightly soil. Ten varieties of triticale were then planted, three rows per variety with a row spacing of approximately 15cm, using broadcast sowing, with a total of 100 seeds. After the triticale seedlings emerged and had three leaves, a salt-alkali stress solution was prepared and soil was prepared according to the method in Example 9, with a target salt content of 0.7%. After four drip irrigations, the average salt content of the 20cm topsoil layer was 0.77%. The growth of the triticale was observed after the saline-alkali soil was prepared, and the triticale was harvested 35 days later to measure biomass. During the observation period, in the second and fourth weeks, 6m... 3 The soil was supplemented with a 20 g / L salt-alkali stress solution per acre of drip irrigation, resulting in an average soil salinity of 0.74% throughout the experimental period. The treatment group was a saline-alkali soil cement pond, the control group was a light soil cement pond, and the field group was the same as in Example 10. After harvesting the triticale, the biomass ratios between the treatment group, field group, and control group were calculated, and the fields were sorted by the ratios of the field group and control group. The results of the triticale field trial's salt tolerance are shown in Table 8.

[0137] Table 8. Results of salt and alkali tolerance assessment of triticale in the field.

[0138] variety CK group Processing group Field group Ratio 1 Ratio 2 Sort Jisi No. 4 1.08±0.18 0.48±0.02 0.44±0.04 0.443 0.409 1 HS139 1.05±0.19 0.40±0.03 0.42±0.04 0.376 0.400 2 Jisi No. 3 1.22±0.14 0.41±0.04 0.42±0.030.03 0.334 0.344 3 21-pin 11 0.93±0.11 0.29±0.03 0.28±0.03 0.312 0.301 4 21-pin 4 0.93±0.13 0.28±0.03 0.28±0.02 0.302 0.301 5 Jisi No. 5 1.11±0.12 0.32±0.04 0.32±0.02 0.289 0.288 6 21-pin 31 1.03±0.12 0.25±0.03 0.28±0.02 0.241 0.272 7 HS287 1.05±0.12 0.21±0.02 0.23±0.02 0.199 0.219 8 HS91 0.99±0.11 0.18±0.03 0.19±0.02 0.184 0.187 9 21-pin 36 1.11±0.13 0.19±0.04 0.19±0.03 0.172 0.171 10

[0139] Note: The data in the table are triticale biomass (kg), ratio 1 is treatment group / CK group, and ratio 2 is field group / CK group.

[0140] As shown in Table 8, the relative biomass of the identified triticale is close to that of the field group, and the ranking of the salt tolerance results of the 10 triticale varieties is consistent with the field identification results. This indicates that the saline-alkali soil of this invention can be used for the salt tolerance identification of shallow-rooted crops (triticale), which can replace the natural saline-alkali land stress environment and achieve the same effect as the identification results of natural saline-alkali land conditions.

[0141] Example 12

[0142] Salt and alkali tolerance threshold test

[0143] Referring to the method for preparing saline-alkali soil in Example 9, saline-alkali soils with different salt contents were formed in large flowerpots (25cm in diameter and 45cm in depth) after drip irrigation with a saline-alkali stress solution. The results showed that the salinity was CK (light soil, 0.08% salt content), 0.13%, 0.21%, 0.32%, 0.44%, 0.51%, and 0.62%, respectively. Seven pots were used for each different saline-alkali soil treatment, and one corn variety, Nongda 108, was planted in each pot with three seedlings per pot. Simultaneously, soil samples were taken from different saline-alkali areas in a field at a farm for testing. Saline-alkali soil areas with similar soil salinity were delineated. The average soil salinity after testing was 0.17%, 0.28%, 0.31%, 0.43%, 0.53%, and 0.65%, respectively, for the control group (CK, light soil, 0.08% salt content). Nongda 108 was planted in these areas. Plant height was measured after 35 days. Scatter plots were created with plant height as the ordinate and soil salinity as the abscissa. A quadratic equation was simulated using Excel software to calculate the salt tolerance threshold, which corresponds to the soil salinity at half the initial plant height. The results are shown in Table 9.

[0144] Table 9 Results of the salt tolerance threshold test for maize

[0145] Quadratic equation simulation threshold Processing group <![CDATA[y=-34.323x 2 -42.33x+43.371, R 2 =0.9429]]> 0.416％ Field group <![CDATA[y=-34.736x 2 -39.443x+43.714,R 2 =0.9358]]> 0.432％

[0146] As shown in Table 9, the obtained salt tolerance threshold for maize is close to that obtained from the field experiment, which is 0.416% and 0.432%, respectively. The error is 3.7% compared with the field group, indicating that the salt tolerance threshold of maize prepared by the present invention can achieve the same effect as the identification results of natural saline-alkali land conditions.

[0147] Comparative Example 1

[0148] Field salt and alkali tolerance test of maize in artificial seawater

[0149] Using a common method such as "A Method for Identifying Salt Tolerance of Asparagus" (CN104472059A), eight gradients of saline water with different mass concentrations were prepared using artificial seawater formulations: CK (freshwater), 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, and 0.7%. Fresh soil was prepared in large flowerpots according to the method in Example 12, and then Nongda 108 was planted in seven pots for each treatment. Subsequently, saline water was periodically applied to the flowerpots using a common method such as "A Method for Identifying Salt and Alkali Tolerance of Industrial Hemp Seedlings" (CN201810610759.X). After 35 days, plant height was measured, and the salt tolerance threshold of maize was tested using the same method as in Example 12. The results showed that the quadratic equation relating maize plant height (y, cm) to soil salinity (x, %) was y = -36.442x.2 -9.7156x+32.121, R 2 =0.8805, with a salt tolerance threshold of 0.557%. Compared with the results of Example 12, this threshold is 33.9% and 28.9% higher than the results of the treatment group and field group in Example 12, respectively. Furthermore, the experiment revealed a significant hardening of the soil surface one week after salt water irrigation. At the end of the experiment, the soil salinity in the shallow layer (0-10 cm) was significantly lower than that in the lower layer (20-40 cm), which may be the reason for the increased salt tolerance threshold of maize. These results indicate that commonly used artificial seawater formulations and conventional salt water irrigation methods cannot produce the same effect as the natural saline-alkali stress environment identified in this invention.

[0150] Example 13

[0151] Indoor corn salt and alkali tolerance identification test

[0152] Using the optimal formula in this invention (NaCl:Na2SO4:MgSO4:Na2CO3:KCl:CaCl2=16:9:9:4:2:1) and the salt-alkali solution formula mentioned in "A Formula for Rapid Identification of Salt Tolerance in Indoor Crops" (201910545547.2), salt-alkali stress solutions with a concentration of 14.35 g / L were prepared according to the method of "Technical Specification for Identification of Salt and Alkali Tolerance of Maize" (DB22 / T2621-2017). Subsequently, salt and alkali tolerance of 10 maize varieties at the seedling stage was identified according to the "Technical Specification for Identification of Salt and Alkali Tolerance of Maize" (DB22 / T2621-2017). The identification results are shown in Table 10.

[0153] Table 10 Comparison Results of Indoor Salt and Alkali Tolerance Testing of Maize

[0154]

[0155]

[0156] Note: Salt tolerance index 1 in the table represents the results of this invention, corresponding to level 1; salt tolerance index 2 represents the results of comparative examples.

[0157] As can be seen from the results in Table 10, although the salt and alkali tolerance indices of corn seedlings obtained by the two salt and alkali solution formulations are not ranked in some varieties, they are consistent in terms of salt and alkali tolerance level. This indicates that the salt and alkali solution of the present invention can not only be used to prepare saline-alkali soil, but can also be extended to indoor salt and alkali tolerance identification under hydroponic or similar hydroponic conditions.

[0158] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing coastal saline-alkali stressed soil, characterized in that, Construct topsoil and create and maintain coastal saline-alkali stress soils by drip irrigation of saline-alkali stress solution; The total mass concentration of the salt-alkali stress solution is 8-20 g / L, and the molar ratio of each component is NaCl:Na2SO4:MgSO4:Na2CO3:KCl:CaCl2=16:(6-12):(6-12):4:2:(0.1-3); The creation requirement is that the salt content in the effective tillage layer of the soil reaches a set value after 2-4 drip irrigations. Each drip irrigation starts when the relative moisture content of the effective tillage layer is ≤13% in the 0-10cm layer, ≤14% in the 10-20cm layer, and ≤15% in the 20cm-40cm layer, and ends when the relative moisture content of the 0-10cm layer is ≤18%, ≤17% in the 10-20cm layer, and ≤16% in the 20cm-40cm layer. The requirement is to start drip irrigation after the salt content in the effective tillage layer of the soil is 0.1-0.2 percentage points lower than the set value, and continue until the salt content recovers to the set value. After drip irrigation, the relative moisture content of the effective tillage layer of the soil is ≤18% for the 0-10cm layer, ≤17% for the 10-20cm layer, and ≤16% for the 20cm-40cm layer.

2. The method for preparing coastal saline-alkali stressed soil according to claim 1, characterized in that, The average soil bulk density of the constructed topsoil layer is 1.3-1.5 g / cm³. 3 The construction method includes filling soil in 10-20cm layers and then compacting it. The compacted bottom soil has a bulk density of 1.4-1.5g / cm³. 3 The density gradually decreases until the top 10cm soil layer has a bulk density of 1.1g / cm³. 3 .

3. The method for preparing coastal saline-alkali stressed soil according to claim 1, characterized in that, The effective depth of the topsoil under salinity stress is 20-40 cm.

4. The method for preparing coastal saline-alkali stressed soil according to claim 1, characterized in that, The creation process also includes an initial drip irrigation volume of 10-15 mg / L of salt-stress solution. 3 / mu, followed by drip irrigation of 6-10m each time. 3 / acre, with a difference of 4-7 days between each drip irrigation.

5. The method for preparing coastal saline-alkali stressed soil according to claim 1, characterized in that, The maintenance also includes each drip irrigation volume of 6-10m. 3 / mu, the concentration of the salt-alkali stress solution is 2-3 times the set soil salinity, and drip irrigation is carried out 1-2 times every 4-7 days.

6. Coastal saline-alkali stressed soil obtained by the method for preparing coastal saline-alkali stressed soil according to any one of claims 1-5.

7. The application of the coastal saline-alkali stress soil described in claim 6 in the identification of plant salt tolerance.

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