Method for increasing emergence rate of severe saline-alkali soil

Abstract

The invention belongs to the field of soil improvement, and provides a method for increasing the emergence rate of severe saline-alkali soil. The method is realized by mixing specific slag charge and saline-alkali soil according to a certain proportion, adding water until the mixture is saturated, and then planting plant seeds. The slag material and the proportion can effectively improve the property of the saline-alkali soil and remarkably increase the emergence rate of the severe saline-alkali soil.

Description

Technical Field

[0001] The invention belongs to the field of soil improvement, and particularly relates to a method for increasing the emergence rate of seedlings in severe saline-alkali land. Background Art

[0002] The main reason for the low emergence rate of saline-alkali land is the adverse effect of its soil environment on crop growth. Saline-alkali land usually contains high concentrations of soluble salts, which causes the concentration of soil solution to be higher than that of plant cell fluid, making it difficult for plant cells to absorb necessary water from the soil. Instead, they lose water due to the effect of osmotic pressure, resulting in physiological dehydration. This dehydration phenomenon can lead to poor root development of crops, yellowing of leaves, stunted growth, and even death. Especially in the seedling stage of crops, because their root system is not yet developed and their tolerance to salt is weak, saline-alkali land often has problems with difficult emergence and low emergence rate. In addition, the soil structure of saline-alkali land is usually poor, with poor air permeability and water permeability, which further aggravates the difficulty of crop growth.

[0003] For the improvement of saline-alkali land, the existing technologies mainly include physical improvement, chemical improvement and biological improvement. Physical improvement mainly improves soil structure, increases soil permeability, reduces evaporation and improves soil salt leaching efficiency through measures such as land leveling, soil addition, covering and tillage. Chemical improvement uses salt-alkali conditioners, strong acid fertilizers and other products to reduce soil salinity and improve the soil environment through chemical methods such as ion exchange and acid-base neutralization. Biological improvement improves soil physical and chemical properties and soil microclimate by introducing, screening and planting salt-tolerant plants, reducing soil moisture evaporation and inhibiting soil salt return.

[0004] Although the existing saline-alkali land improvement technology has achieved certain results, it still has some shortcomings. Physical improvement methods often require a lot of water resources and manpower input, are costly, and have poor durability, and are easily affected by weather and soil conditions. Although chemical improvement methods can quickly reduce soil salinity, they may cause secondary pollution to the soil environment, require continuous use, and are costly. Although biological improvement methods have the advantages of environmental protection and sustainability, the improvement process is slow and it takes a long time to see obvious results. At the same time, since each plant has its own salt tolerance range, other improvement measures and fertilizer management must be coordinated during the introduction and planting of salt-tolerant plants.

[0005] Therefore, we urgently need a low-cost, healthy, environmentally friendly and easy-to-operate method to increase the seedling emergence rate in severely saline-alkali land. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a method for increasing the emergence rate of heavy saline-alkali land. The method realizes effective improvement of saline-alkali soil by improving soil structure, changing water flow mode, inhibiting the rise of water-soluble salts and promoting crop growth. This improvement method not only improves the suitability of soil, but also promotes the healthy growth of crops, while realizing effective utilization of resources and protection of the environment.

[0007] The technical solution of the present invention is:

[0008] A method for increasing the emergence rate of heavy saline-alkali land mainly comprises the following steps:

[0009] (1) mixing the slag with saline-alkali soil to obtain a slag-soil mixture, and then adding water until the slag-soil mixture is saturated;

[0010] (2) Plant the seeds on the soil mixture in (1) and irrigate with 2 cm of water every 3 days until seedlings emerge.

[0011] Preferably, (1) the middle residue is selected from any one or any two of fungus residue, switchgrass powder residue, cotton stalk residue, fly ash residue, and fly ash fine ash;

[0012] Wherein, the mushroom residue is selected from any one of Pleurotus eryngii and Lentinus edodes mushroom residue;

[0013] Switchgrass powder: harvest switchgrass, dry it, and crush it into pieces less than 0.5 cm in length;

[0014] Cotton stalk residue: harvest cotton stalks, dry them, and crush them into pieces less than 0.5 cm in length;

[0015] Fly ash slag: taken from the local thermal power plant;

[0016] Fly ash fine ash: taken from the local thermal power plant.

[0017] Preferably, the volume ratio of (1) the middle slag to the soil is 2:1.

[0018] Preferably, the seeds in (2) are switchgrass seeds; and the planting depth is 0-3 cm.

[0019] During the long-term in-depth research and testing of saline-alkali land, the inventors found that the main reason why saline-alkali land remains saline-alkali for a long time is that its soil is compacted and has narrow gaps, which leads to the capillary structure of the soil. This structure allows water containing soluble salts to rise to the surface of the soil layer under capillary action. When the water evaporates, the soluble salts remain on the surface of the soil, thus maintaining the salinity. When it rains, although the salinity on the surface of the soil layer will temporarily decrease, this process will repeat after the rain stops, allowing the saline-alkali land to maintain its salinity for a long time.

[0020] In order to effectively improve the planting environment of saline-alkali land, the technical solution proposed in the present invention uses fungus residue or plant residue to fully mix with saline-alkali soil. This method makes the soil no longer compacted, the air permeability is significantly improved, and the gaps between soil particles are also enlarged, thereby destroying the original capillary structure. In the mixed layer (depth of 10-15cm) formed on the soil surface, the flow of water loses the support of capillary action and can no longer flow from bottom to top in a liquid state, but can only escape in the soil gaps in the form of water vapor. In this way, the water-soluble salt loses its rising carrier and can only stay in the compacted layer below the mixed layer. This mechanism maintains the salt washing effect of the mixed layer, so that the soil is improved and becomes more suitable for crop growth.

[0021] Compared with the prior art, the present invention has the following advantages and effects:

[0022] (1) It can effectively improve saline-alkali land. Specific data show that when the ratio of fly ash fine ash to saline-alkali soil is 2:1, the conductivity is reduced from 4.38μs / cm (August 10) to 1.01μs / cm (September 9); when the ratio of mushroom residue: switchgrass residue: saline-alkali soil is 1:1:1, the salt content is reduced from 2.30μs / cm (August 10) to 1.02μs / cm (September 9); pH is reduced from the initial 8.2-8.9 to 7-8;

[0023] (2) It can effectively increase the emergence rate of switchgrass in severe saline-alkali soil. When the ratio of fly ash fine ash to saline-alkali soil is 2:1 and the ratio of mushroom residue: switchgrass residue: saline-alkali soil is 1:1:1, the emergence rate of switchgrass increased from 0 to 19.7%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the experimental site in the present invention;

[0025] Figure 2 This is a conductivity test record table after different media and saline-alkali soil are mixed in a ratio of 2:1 in Example 1 of the present invention;

[0026] Figure 3 This is a conductivity test record table after different media and saline-alkali soil are mixed in a ratio of 1:1:1 in Example 1 of the present invention;

[0027] Figure 4 This is a conductivity detection record table after the fungus residue and saline-alkali soil are compounded in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in conjunction with specific implementation methods.

[0029] 1.1 Experimental materials

[0030] The mushroom residue mentioned in the present invention is Pleurotus eryngii mushroom sticks and Lentinus edodes mushroom sticks;

[0031] The switchgrass powder residue is obtained by harvesting switchgrass, drying it, and crushing it into pieces less than 0.5 cm in length;

[0032] Cotton stalk residue is harvested cotton stalks, dried and crushed to less than 0.5 cm in length;

[0033] The fly ash slag is obtained from the local thermal power plant;

[0034] Fly ash fine ash is taken from the local thermal power plant.

[0035] The production process and composition of power plant ash and fly ash:

[0036] Production process: The coal blocks entering the thermal power plant first enter the pulverizer to be ground into fine coal powder, which is then blown into the boiler for combustion. After combustion, the heavier coal slag is discharged and collected at the bottom of the furnace, and the fine fly ash particles enter the electrostatic dust collector after the exhaust gas is cooled, where the dust is adsorbed and collected.

[0037] The main components of power plant ash and fly ash are: silicon dioxide, aluminum oxide, iron oxide, calcium oxide; the secondary components are magnesium oxide, potassium oxide, calcium oxide, etc.

[0038] 1.2 Example 1 Conductivity Experiment

[0039] Steps for the conductivity experiment:

[0040] (1) On a flat saline-alkali land with the same salinity (salt content above 2%), 54 square pits with a length, width and depth of 50 cm × 50 cm × 15 cm were dug, divided into 9 rows, with 6 pits in each row, for a total of 9 groups;

[0041] (2) The distance between the square pits is 40 cm;

[0042] (3) Nine groups of experiments were conducted according to the composition and volume ratio of the slag-soil mixture in Table 1 below. In the slag-soil mixture, "slag" refers to any one or two of fungus slag, switchgrass powder slag, cotton stalk slag, fly ash slag, and fly ash fine ash, and "soil" refers to saline-alkali soil (with a salt content of more than 2%).

[0043] Table 1 Main components and volume ratio of the soil mixture in the pit

[0044]

[0045]

[0046] As shown in Table 1 , 15 cm thick muck-soil mixture was added to the square pit in experimental groups 1 to 9;

[0047] Among them, the volume ratio of "slag": "soil" in experimental groups 1 to 5 is 2:1; the composition and volume ratio of the slag-soil mixture in experimental groups 6 to 9 are:

[0048] Group 6: a mixture of mushroom residue, switchgrass powder residue, and saline-alkali soil in a volume ratio of 1:1:1;

[0049] Group 7: a mixture of fungus residue, cotton stalk powder residue, and saline-alkali soil in a volume ratio of 1:1:1;

[0050] Group 8: a mixture of fungus residue, fly ash residue and saline-alkali soil in a volume ratio of 1:1:1;

[0051] Group 9: mixture of fungus residue, fly ash, and saline-alkali soil in a volume ratio of 1:1:1;

[0052] Inject the same weight of water into the square pits of each group above, and the amount of water injected shall be based on the saturation of the slag.

[0053] (4) Conduct conductivity test on the soil mixture at the top of each group at 8:00 a.m. every day, and conduct the test for more than 15 times a day until the deviation of the average conductivity of the same group after two consecutive tests does not exceed 5%. Fill in the conductivity data record, see Figure 2 to Figure 4 Among them, when the ratio of fly ash fine ash to saline-alkali soil was 2:1, the conductivity decreased from 4.38μs / cm (August 10) to 1.01μs / cm (September 9), and when the ratio of mushroom residue: switchgrass residue: saline-alkali soil was 1:1:1, the salt content decreased from 2.30μs / cm (August 10) to 1.02μs / cm (September 9);

[0054] Figure 2 to Figure 4 The conductivity data show that the slag soil can effectively reduce the salt content in saline-alkali soil after being mixed in a certain ratio.

[0055] Analysis of the reasons: After the fungus residue or plant residue is fully mixed with the saline-alkali soil, the structure of the soil changes significantly. It no longer becomes compacted, but the air permeability increases, and the gaps between soil particles expand. This change leads to the destruction of the capillary structure of the soil, especially in the mixed layer formed on the soil surface (depth of about 10-15cm), the flow of water loses the capillary effect that it originally relied on. Therefore, water can no longer flow upward from the lower layer of the soil in a liquid state, but can only escape from the cracks in the soil in the form of water vapor. Since the water-soluble salts have lost their rising carrier, they can only stay in the compacted layer below the mixed layer, thus maintaining the salt washing effect of the mixed layer.

[0056] While testing the conductivity, the inventors also measured the pH of the soil in the plot. The data showed that the initial pH value was between 8.2 and 8.9 at the beginning of the experiment; after being improved with the slag soil mixture, the pH value dropped to between 7 and 8, which is suitable for the emergence and growth of salt-alkali tolerant crops.

[0057] Therefore, after being improved with the slag-soil mixture, the salinity of the soil becomes lower, making it more suitable for the emergence and growth of crops.

[0058] Example 2 Seedling rate experiment

[0059] 2.1 Design planting plan

[0060] During the test, the ambient temperature was 15-22°C and the humidity was 60%-80%.

[0061] (1) Each row of 6 square pits is divided into 3 A-type and 3 B-type;

[0062] (2) In the three pits of item A, 100 seeds of switchgrass with full grains were evenly planted at a depth of 2-3 cm and watered until saturated; in the three pits of item B, 100 seeds of switchgrass with full grains were evenly sprinkled on the surface, the surface soil layer was loosened with a small rake, and watered until saturated; the emergence of switchgrass seedlings requires a certain degree of air permeability. If the air permeability is poor, the emergence rate will be low;

[0063] (3) Water 2 cm every 3 days (or postpone it if it rains) until the seedlings emerge;

[0064] (4) Ten days after the first seedling emerges from the same pit, count the number of seedlings emerging from each pit and calculate the emergence rate.

[0065] Description: Synchronously, 300 switchgrass seeds (100 seeds in each dish) were planted in 3 culture dishes at a constant temperature (25°C, 80-85% humidity) to test the germination rate.

[0066] 2.2 Control experiment and comparative experiment

[0067] 2.2.1 Control group: On the nearest smooth ground with the same salinity, after leveling, mark out 6 squares with the same length and width as the soil pits. After loosening the soil, conduct a synchronous seedling emergence experiment with the 54 soil pits above, and use it as a control for other groups.

[0068] 2.2.2 Comparison group: add 6 soil pits of the same specifications, evenly divided into item A and item B, with three soil pits in each item, and fill them with a mixture of slag soil with a volume ratio of 1:1:1 of mushroom residue, switchgrass residue, and saline-alkali soil, and a mixture of slag soil with a volume ratio of 1:1:1 of mushroom residue, cotton stalk residue, and saline-alkali soil; and plant the same number of switchgrass seeds simultaneously, with the planting depth of item A being 2cm and the planting depth of item B being the surface. After that, water and cover the soil with film for comparison experiment.

[0069] 2.3 Experimental Conclusion

[0070] Table 2 Statistics of germination rate

[0071]

[0072] Analyzing the relevant data in Table 2, we can see that:

[0073] (1) The emergence rate of the blank heavy salt control group was 0, indicating that the planting environment of switchgrass in the present invention was very bad;

[0074] (2) The germination rates of the experimental groups were higher than those of the blank groups, indicating that the use of the slag-soil mixture in the present invention can effectively improve the environment of saline-alkali land and increase the germination rate of severe saline-alkali land;

[0075] Among them, the germination rates of experimental groups 2 to 9 planted on the surface were greater than those planted at 2-3 cm, especially the germination rates of groups 5 and 6 were as high as 19.7%; the technical schemes adopted by these two groups were: surface planting on a mixture of fly ash fine ash and saline-alkali soil in a ratio of 2:1, and surface planting on a mixture of fungus residue: switchgrass residue: saline-alkali soil = 1:1:1. The reason for its significant beneficial effect is that after fine fly ash is mixed with saline-alkali soil, due to its high porosity and large specific surface area, and its main component is sintered silica, it adsorbs and adheres to silica in the natural state in the soil to form larger particles, which leads to the expansion of gaps between the soil, more thorough capillary destruction, and better air permeability. In the mixture of mushroom residue: switchgrass residue: saline-alkali soil = 1:1:1, the mushroom residue has been decomposed and has good water absorption; while the switchgrass residue is not decomposed, has a length of 0.5 cm, and forms a larger supporting space and larger gaps. The combination of the two provides better conditions for germination.

[0076] (3) During the experiment, to the surprise of the inventors, the data of Group 1 (mushroom residue to saline-alkali soil ratio of 2:1) were different from those of the other experimental groups. When the mushroom residue to saline-alkali soil ratio was 2:1, the germination rate of switchgrass seeds planted on the surface was lower than that planted at 2-3 cm. The reasons for this were analyzed as follows: due to the high mushroom residue content, the surface soil was washed away during heavy rain or rainstorm, resulting in fast drying speed, low humidity in the seed environment, and low germination rate. Planting at 2-3 cm effectively avoided the above disadvantages.

[0077] (4) The effect of laying plastic film is obviously negative, and the result is not as good as the effect of multiple rain showers in summer. The main reason is that the germination of switchgrass seeds requires high air permeability. After covering with film, the air permeability becomes worse, and the effect becomes worse.

[0078] In summary, the method for increasing the emergence rate of severely saline-alkali land provided by the present invention utilizes a slag-soil mixture to improve soil structure, change the water flow pattern, inhibit the rise of water-soluble salts, and promote crop growth, thereby achieving effective improvement of saline-alkali soil.

[0079] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent changes and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for increasing the emergence rate of heavy saline-alkali land, mainly comprising the following steps: (1) Mixing the slag with saline-alkali soil to obtain a slag-soil mixture, and then adding water until the slag-soil mixture is saturated; (2) Plant the seeds in the soil mixture prepared in (1) and irrigate with 2 cm of water every 3 days until seedlings emerge.

2. A method for increasing the emergence rate of saline-alkali soil as described in claim 1, characterized in that: The (1) middle residue is selected from any one or any two of fungus residue, switchgrass powder residue, cotton stalk residue, fly ash residue, and fly ash fine ash.

3. A method for increasing the emergence rate of saline-alkali land as described in claim 1, characterized in that: The volume ratio of slag to soil in (1) is 2:

1.

4. A method for increasing the emergence rate of saline-alkali land as described in claim 1, characterized in that: The seeds in (2) are switchgrass seeds; the planting depth is 0-3 cm.

5. A method for increasing the emergence rate of saline-alkali land as described in claim 2, characterized in that: The mushroom residue is selected from any one of Pleurotus eryngii and Lentinus edodes mushroom residues; The switchgrass powder residue is obtained by harvesting switchgrass, drying it, and crushing it into pieces less than 0.5 cm in length; Cotton stalk residue is harvested cotton stalks that are dried and crushed to a length of less than 0.5 cm.

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