A comprehensive method for improving saline-alkali soil

Abstract

The application provides a comprehensive improvement method for saline-alkali soil, and belongs to the technical field of soil improvement. The method comprises the steps of applying modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer on the surface of the saline-alkali soil, and then interplanting Suaeda salsa and rice bean. The method can significantly reduce the total salt content, pH value and alkalization degree of the saline-alkali soil, and improve the organic matter content of the soil. The improvement time is short, the quality of the saline-alkali soil can be significantly improved, and the yield of crops can be increased.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology, and in particular relates to a comprehensive method for improving saline-alkali soil. Background Technology

[0002] Saline-alkali soil is a degraded soil type with poor agricultural productivity, and it covers a large area of ​​the world. Against the backdrop of a global food crisis, the reclamation of saline-alkali land is of great significance for solving the food problem for people worldwide. Topography, climate, and human activities are the main causes of soil salinization. Due to the high groundwater level in coastal wetlands, the groundwater contains large amounts of soluble salts, which move with the rising water flow and evaporation, accumulating on the topsoil and forming typical coastal saline-alkali land. The high salt content and severe alkalization of coastal saline-alkali land lead to severe degradation of soil structure and performance and have toxic effects on plants, thereby reducing crop yields and restricting agricultural development. Improving crop growth conditions in saline-alkali land and making coastal areas important farmland protection zones is of great significance for solving the shortage of arable land resources.

[0003] Currently, there are various ecological regulation measures for improving coastal saline-alkali land soil, including various physical, chemical, biological, and water conservancy projects to save water and reduce salt content and mitigate salinity barriers. The main principle is to achieve regulation by reducing surface evaporation, creating barriers to inhibit upward salt movement, and promoting salt leaching to accelerate soil desalination. However, the improvement and utilization of severely saline-alkali land is complex, costly, and slow, resulting in difficulties in promoting and applying saline-alkali land improvement technologies, poor long-term effectiveness and sustainability, and low social participation. Therefore, it is necessary to establish a low-cost method for improving severely saline-alkali land and form a virtuous cycle technology model for saline-alkali land agriculture that uses land to nourish land.

[0004] In response to the problems of low organic matter content, compaction, hardness, lack of granular structure, limited microbial diversity, and high salinity of saline-alkali soils, as well as the technical challenge of long improvement times with single biological measures, this invention provides a method for improving saline-alkali soils in order to improve soil quality and increase crop yields. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a comprehensive method for improving saline-alkali soil.

[0006] To achieve the above objectives, the present invention provides a comprehensive method for improving saline-alkali soil, comprising applying modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the surface of saline-alkali soil, followed by crop rotation of Suaeda salsa and Sesbania scoparia.

[0007] Furthermore, the modified carbon-based organic fertilizer contains ≥30% organic matter by mass (based on dried basis) and ≥20% modified biochar by mass (based on carbon).

[0008] Furthermore, the modified carbon-based organic fertilizer, by mass, comprises 40-60 parts of well-rotted manure, 10-20 parts of modified biochar, 5-15 parts of potassium humate, 10-30 parts of phosphogypsum, 0.1-1 parts of polyglutamic acid, and 1-5 parts of binder.

[0009] Furthermore, the modified carbon-based organic-inorganic compound fertilizer has a N, P2O5 and K2O mass ratio of 7:5:3, an organic matter mass fraction (based on dried basis) of ≥20%, and a modified biochar mass fraction (based on carbon) of ≥15%.

[0010] Furthermore, the modified carbon-based organic-inorganic compound fertilizer, by mass, comprises 30-40 parts of well-rotted manure, 5-15 parts of distiller's grains, 5-15 parts of modified biochar, 10-20 parts of urea, 5-10 parts of ammonium sulfate, 5-15 parts of potassium sulfate, 10-20 parts of monoammonium phosphate, 0.5-1.5 parts of calcium magnesium phosphate, 0.1-1 parts of trace elements, and 2-5 parts of binder.

[0011] Furthermore, the application rate of the modified carbon-based organic fertilizer is 100-300 kg / mu, and the application rate of the modified carbon-based organic-inorganic compound fertilizer is 50-100 kg / mu.

[0012] This invention involves applying modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the surface of saline-alkali soil. The modified carbon-based organic fertilizer can increase the porosity of saline-alkali soil, improve soil permeability, promote soil particle aggregation, promote nutrient transformation, and improve nutrient availability. The modified carbon-based organic-inorganic compound fertilizer can slow down the release rate of nitrogen, phosphorus, and potassium, improve fertilizer utilization, and reduce the cumulative salt damage caused by fast-acting fertilizers to seeds and seedlings.

[0013] Furthermore, the sowing rate of Suaeda salsa is 1-3 kg / mu, and the sowing rate of Sesbania serrata is 3-6 kg / mu.

[0014] Furthermore, the planting time for Suaeda salsa is from early to mid-April, and the harvesting time is from mid to late June. A self-propelled combine harvester can be used, and the Suaeda salsa removed from the field can be used as forage or for producing lick bricks, depending on demand.

[0015] Furthermore, the planting time for the sesame is from early to mid-July. When the sesame reaches a height of 1.3m to 1.5m, it is harvested, leaving a stubble height of 50cm to 60cm.

[0016] Furthermore, the sesame cuttings are laid flat between the sesame rows.

[0017] Furthermore, sesame seeds are plowed back into the field during their peak flowering period.

[0018] Furthermore, during the peak flowering period of sesbania, corn stalk crushing and returning machinery is used to crush the sesbania to a length of 5cm to 8cm, and deep plowing is carried out using a reversible plow to a compaction depth of 25cm to 30cm.

[0019] The plants used for crop rotation in this invention, Suaeda salsa and Sesbania scoparia, are both salt-tolerant plants.

[0020] Among them, Suaeda salsa can continuously absorb salt ions in saline-alkali soil, and at the same time, it can absorb irrigation water from the soil to increase the thickness of cell walls. It can actively store salt ions and other ions that are harmful to plant growth in cell vacuoles, thus avoiding the stress of salt ions on halophytes. This greatly improves the tolerance and endurance of halophytes in moderate and severe saline-alkali soils. Furthermore, by harvesting Suaeda salsa, the salt content in the soil can be removed from the soil to achieve the effect of soil desalination.

[0021] Sesbania is salt-tolerant, flood-tolerant, and tolerant of poor soil. It grows rapidly and has a large biomass, making it a preferred green manure variety for quickly increasing the organic matter content of tidal flat soils. Therefore, planting sesbania during crop rotation can rapidly reduce soil salinity and allow for the accumulation of organic matter. Sesbania is harvested during its vigorous growth period, and the stubble left after harvesting can grow rapidly. Harvesting doubles the biomass of sesbania when returned to the field, and the tender plants decompose easily, greatly increasing the decomposition rate of green manure and the organic matter content of the soil. After harvesting, spreading sesbania evenly between rows as a cover can effectively reduce the accumulation of salt ions on the surface caused by surface transpiration through soil capillaries. Harvesting sesbania further promotes its growth and improves the soil.

[0022] Furthermore, before applying modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the surface of saline-alkali soil, the process also includes removing field debris, weeding, leveling the field, deep plowing the land, and drying it.

[0023] Furthermore, after applying modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the surface of saline-alkali soil, the process also includes plowing, harrowing, and leveling the land to form raised beds.

[0024] Furthermore, the width of the furrows in the paddy fields is 1.5–2.0m, the depth of the ditches is 20–30cm, and the spacing between the ditches is 30–35cm.

[0025] Furthermore, the seeds of Suaeda salsa and Sesbania scoparia need to be pretreated before planting, specifically including the following steps: soaking Suaeda salsa seeds in 10-20 ppm ABT6 rooting solution for 1-4 hours, then draining and air-drying the Suaeda salsa seeds; soaking Sesbania scoparia seeds in 60℃ hot water, letting the water cool naturally, taking them out and air-drying for 1 day, then soaking them in 15-30 ppm ABT6 rooting solution for 5-10 hours, and then air-drying them.

[0026] Furthermore, when sowing Suaeda salsa seeds, spray the seeds with a bacterial solution diluted 200 to 300 times, then mix the seeds with fine soil and sow them evenly on the surface of the raised beds.

[0027] Furthermore, after sowing sesame seeds, apply 5-10L of bacterial solution per acre with irrigation water.

[0028] Furthermore, the bacterial solution used after sowing Suaeda salsa seeds and Sesbania serrata seeds is made from yeast, Bacillus subtilis, Bacillus megaterium, and lactic acid bacteria, with a spraying rate of 5-10 L / mu.

[0029] More specifically, the present invention provides a comprehensive method for improving saline-alkali soil, which includes the following steps:

[0030] (1) Land preparation and fertilization

[0031] Remove debris and weeds from the field to level the soil. Deep plow the land and let it dry for 4-6 days. Then, apply modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the soil surface. The application rate of modified carbon-based organic fertilizer (organic matter mass fraction (on a dry basis) ≥30% and modified biochar mass fraction (on a carbon basis) ≥20%) is 100-300 kg / mu. The application rate of modified carbon-based organic-inorganic compound fertilizer (N, P2O5 and K2O mass ratio of 7:5:3, organic matter mass fraction (on a dry basis) ≥20% and modified biochar mass fraction (on a carbon basis) ≥15%) is 50-100 kg / mu. Then, shallow plow the soil.

[0032] Plow and harrow the land to form raised beds, with beds 1.5m to 2.0m wide, furrows 20cm to 30cm deep, and furrows spaced 30cm apart.

[0033] (2) Seed pretreatment

[0034] Seed selection: Select Suaeda salsa seeds and Sesbania seeds that are free from mold and damage;

[0035] Soak Suaeda salsa seeds in 10-20 ppm ABT6 rooting solution for 1-4 hours, then drain and air dry. Soak Sesbania seeds in 60℃ hot water, let the water cool naturally, take them out and air dry for 1 day, then soak them in 15-30 ppm ABT6 rooting solution for 5-10 hours, and then air dry.

[0036] (3) Suaeda salsa cultivation

[0037] Sowing: Sow Suaeda salsa seeds in early to mid-April. When sowing, spray the seeds with a 200-300 times diluted bacterial solution (made from yeast, Bacillus subtilis, Bacillus megaterium and lactic acid bacteria, with a spraying rate of 5-10 L / mu). Then mix the seeds with fine soil and sow them evenly on the surface of the raised beds. The sowing rate of Suaeda salsa seeds is 1-3 kg / mu.

[0038] Harvesting: Harvesting will take place in mid-to-late June. A self-propelled combine harvester can be used. The Suaeda salsa removed from the field can be used as forage or for producing lick bricks, depending on the needs.

[0039] (4) Sesbania planting

[0040] The planting time for sesame seeds is from early to mid-July. The planting method is row sowing with a row spacing of 50cm and a sowing rate of 3-6kg / mu. After sowing, apply 5L-10L of bacterial solution per mu with irrigation water.

[0041] Harvesting: When the sesame plants reach a height of 1.3m to 1.5m, they should be harvested, leaving a stubble height of 50cm to 60cm. The harvested sesame plants should be evenly spread between the rows of sesame plants to prevent water evaporation, reduce salinity, increase soil organic matter, and improve soil structure.

[0042] Turning and returning to the field: During the peak flowering period of sesbania, corn stalk crushing and returning machinery is used to crush the sesbania to a length of 5cm to 8cm. A reversible plow is then used for deep turning, with a turning depth of 25cm to 30cm.

[0043] Compared with the prior art, the present invention has the following advantages and technical effects:

[0044] This invention employs a method of applying modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the surface of saline-alkali soil, followed by crop rotation of Suaeda salsa and Sesbania scoparia. This method can be used to improve moderately and severely saline-alkali soils, significantly reducing the total salt content, pH value, and alkalinity of saline-alkali soils, while increasing the soil organic matter content. The improvement time is short, and it can significantly improve the quality of saline-alkali soils and increase crop yields. Detailed Implementation

[0045] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0046] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0047] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0048] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0049] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0050] The modified carbon-based organic fertilizer used in this embodiment of the invention comprises, by weight, 55 parts of well-rotted manure, 15 parts of modified biochar, 10 parts of potassium humate, 20 parts of phosphogypsum, 0.2 parts of polyglutamic acid, and 3 parts of binder (attapulgite powder, particle size not required). It is prepared by extrusion granulation, and the organic matter content (on a dried basis) is ≥30%, and the modified biochar content (on a carbon basis) is ≥20%.

[0051] The modified carbon-based organic-inorganic compound fertilizer used in this embodiment of the invention comprises, by weight, 34 parts of well-rotted manure, 10 parts of distiller's grains, 10 parts of modified biochar, 12 parts of urea, 8 parts of ammonium sulfate, 10 parts of potassium sulfate, 15 parts of monoammonium phosphate, 1 part of calcium magnesium phosphate, 0.1 parts of manganese sulfate, 0.5 parts of amino acid chelated iron, 0.05 parts of amino acid chelated zinc, 0.2 parts of borax, and 3 parts of binder (attapulgite powder, particle size not required). It is prepared by extrusion granulation. Testing showed that the mass ratio of N, P2O5, and K2O was 7:5:3, the mass fraction of organic matter (on a dried basis) was ≥20%, and the mass fraction of modified biochar (as carbon) was ≥15%.

[0052] The preparation of modified biochar for modified carbon-based organic fertilizer / modified carbon-based organic-inorganic compound fertilizer in this embodiment of the invention includes the following steps: using corn stalks as raw material, crushing them to a particle size of less than 1 cm, preparing them using biochar gas cogeneration equipment, carbonization temperature of 600℃, carbonization time of 40 min, adding potassium carbonate as a chemical modifier during the carbonization process, and introducing water vapor and carbon dioxide gas from the bottom of the carbonization furnace for 30 min to obtain the modified biochar. The ratio of corn stalks, potassium carbonate, water vapor and carbon dioxide used in the preparation process is 1 t: 30 kg: 12 kg: 1 kg.

[0053] The bacterial broth used in this embodiment of the invention is made from yeast, Bacillus subtilis, Bacillus megaterium and lactic acid bacteria. Specifically, the yeast fermentation broth, Bacillus subtilis fermentation broth, Bacillus megaterium fermentation broth and lactic acid bacteria fermentation broth are mixed in a volume ratio of 1:2:2:1.

[0054] The method for preparing yeast fermentation broth is as follows: Weigh out 5 parts glucose, 1 part peptone, 0.5 parts yeast powder, 0.2 parts potassium dihydrogen phosphate, and 0.05 parts magnesium sulfate by weight; add 95 parts filtered water to dissolve, autoclave for 30 minutes to complete the preparation of the culture medium; in a fermenter, inoculate the brewing yeast with the culture medium at an inoculation rate of 2%; maintain the temperature at 28℃ and incubate with liquid ventilation for 13 hours to obtain yeast fermentation broth.

[0055] The preparation method of Bacillus subtilis fermentation broth is as follows: Weigh 1 part glucose, 3 parts starch, 5 parts soybean meal powder, 0.5 parts magnesium sulfate, and 0.5 parts sodium chloride by weight; add 90 parts filtered water to dissolve, autoclave for 30 minutes to complete the preparation of the culture medium; in the fermenter, inoculate Bacillus subtilis or Bacillus licheniformis with the culture medium at an inoculation rate of 1%; maintain the temperature at 30℃ and incubate with liquid ventilation for 15 hours to obtain Bacillus subtilis fermentation broth.

[0056] The preparation method of Bacillus megaterium fermentation broth is as follows: Weigh 0.5 parts sucrose, 0.5 parts starch, 3 parts soybean meal powder, 0.5 parts yeast powder, 0.5 parts potassium dihydrogen phosphate, and 0.5 parts dipotassium hydrogen phosphate by weight, add 94.5 parts filtered water to dissolve, and autoclave for 30 minutes; inoculate into a fermenter at an inoculation rate of 2%, and incubate at 30°C with liquid ventilation for 14 hours to obtain Bacillus megaterium fermentation broth.

[0057] The preparation method of lactic acid bacteria fermentation broth is as follows: Take 3 parts glucose, 3 parts brown sugar, 0.5 parts peptone, 0.5 parts yeast powder, 0.2 parts potassium dihydrogen phosphate, and 0.2 parts magnesium sulfate by weight; add 95 parts filtered water to dissolve, autoclave for 30 minutes to complete the preparation of the culture medium; in the fermenter, inoculate Lactobacillus plantarum or Lactobacillus acidophilus with the culture medium at an inoculation rate of 2%; maintain the temperature at 37℃ and anaerobic culture for 20 hours to obtain lactic acid bacteria fermentation broth.

[0058] The ABT6 rooting solution used in this embodiment of the invention was purchased from Beijing Aibiti Biotechnology Co., Ltd.

[0059] The technical solution of the present invention will be further illustrated by the following embodiments.

[0060] Example 1 and Comparative Example 1 of this invention relate to the improvement of severely saline-alkali land. Both were conducted from April 2020 to October 2021 in severely saline-alkali land in Zhonghaibin Village, Leting County, Tangshan City, Hebei Province. This severely saline-alkali land in Zhonghaibin Village is a coastal saline-alkali land area in my country. The total area of ​​the experimental field for each example or comparative example was 8 mu (approximately 1.33 hectares), with three replicates each, and the average value was taken. Before the experiment, the basic soil sample test results showed that the top 0–20 cm soil was silty loam, with an average total salt content of 6.4 g / kg and a pH value of 9.3.

[0061] Example 1

[0062] This embodiment provides a comprehensive method for improving saline-alkali soil, which specifically includes the following steps:

[0063] (1) Land preparation and fertilization

[0064] Remove debris and weeds from the field to level the field; deep plow the land and let it dry for 5 days, then apply modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the soil surface. The application rate of modified carbon-based organic fertilizer is 300 kg / mu and the application rate of modified carbon-based organic-inorganic compound fertilizer is 50 kg / mu. Then, shallow plow the land.

[0065] Plow and harrow the land to form raised beds, each 1.5m wide, with furrows 30cm deep and 35cm apart.

[0066] (2) Seed pretreatment

[0067] Seed selection: Select Suaeda salsa seeds and Sesbania seeds that are free from mold and damage;

[0068] Soak the seeds of Suaeda salsa in 15ppm ABT6 rooting solution for 2 hours, then drain and air dry them. Soak the seeds of Sesbania serratifolia in 60℃ hot water, let the water cool naturally, take them out and air dry for 1 day, then soak them in 25ppm ABT6 rooting solution for 7 hours, and then air dry them.

[0069] (3) Suaeda salsa cultivation

[0070] Sowing: On April 10, 2022, Suaeda salsa seeds were sown. When sowing, the seeds were sprayed with a 250-fold diluted bacterial solution (10L / mu). Then, the seeds were mixed with fine soil and sown on the surface of the flat beds. The sowing amount of Suaeda salsa seeds was 3kg / mu.

[0071] Harvesting: Harvest on June 25th using a self-propelled combine harvester. The removed Suaeda salsa can be used as forage or for producing lick bricks, depending on demand.

[0072] (4) Sesbania planting

[0073] The planting time for sesame seeds is July 5th. The planting method is row sowing with a row spacing of 50cm and a sowing rate of 6kg / mu. After sowing, apply 10L of bacterial solution per mu with irrigation water.

[0074] Harvesting: Harvested on August 20th, the sesame plants reached a height of 1.5m, with a stubble height of 60cm. The harvested sesame plants were evenly spread between the rows of sesame plants.

[0075] Turning and returning to the field: On October 9, when the sesbania is in full bloom, corn stalk crushing and returning machinery is used to crush the sesbania to a length of about 6cm. Then, a reversible plow is used for deep turning, with a turning depth of 30cm.

[0076] Comparative Example 1

[0077] Same as Example 1, except that only Suaeda salsa is planted, and the specific method is as follows:

[0078] (1) Land preparation and fertilization

[0079] Remove debris and weeds from the field to level the field; deep plow the land and let it dry for 5 days, then apply modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the soil surface. The application rate of modified carbon-based organic fertilizer is 300 kg / mu and the application rate of modified carbon-based organic-inorganic compound fertilizer is 50 kg / mu. Then, shallow plow the land.

[0080] Plow and harrow the land to form raised beds, each 1.5m wide, with furrows 30cm deep and 35cm apart.

[0081] (2) Seed pretreatment

[0082] Seed selection: Select Suaeda salsa seeds that are free from mold and damage;

[0083] Soak the Suaeda salsa seeds in 15ppm ABT6 rooting solution for 2 hours, then drain and air dry the seeds.

[0084] (3) Suaeda salsa cultivation

[0085] Sowing: On April 10, 2022, Suaeda salsa seeds were sown. When sowing, the seeds were sprayed with a 200-fold diluted bacterial solution (10L / mu). Then, the seeds were mixed with fine soil and sown on the surface of the flat beds. The sowing amount of Suaeda salsa seeds was 3kg / mu.

[0086] Harvesting: Harvest on June 25th using a self-propelled combine harvester. The removed Suaeda salsa can be used as forage or for producing lick bricks, depending on demand.

[0087] Detection indicators and results

[0088] In Example 1, after returning sesame to the field, and in Comparative Example 1, after harvesting Suaeda salsa, soil samples were collected from 0 to 20 cm depths to test soil salinity and organic matter content. The results are shown in Table 1.

[0089] Table 1. Results of soil salinity and organic matter content measurements in the examples and comparative examples.

[0090] deal with Salt content (g / kg) pH value Basicity (%) Organic matter (g / kg) Comparative Example 1 (Suaeda salsa) 5.5 8.5 17.2 13.3 Example 1 (Suaeda salsa + Guava) 4.2 8.1 15.4 15.2

[0091] As shown in Table 1, the rotation of Suaeda salsa and Sesbania serratifolia according to the method of Example 1 of the present invention resulted in a 23.6% reduction in total soil salinity, a 0.4-unit reduction in pH value, and a 10.5-percentage-point reduction in alkalinity compared to Comparative Example 1 which only planted Suaeda salsa. The soil organic matter content increased by 14.3%, indicating that the method of the present invention can effectively improve saline-alkali soil.

[0092] Example 2 and Comparative Example 2 of this invention relate to the improvement of moderately saline-alkali land. Both were conducted from April 2022 to October 2021 in moderately saline-alkali land in Xintian Village, Leting County, Tangshan City, Hebei Province. This moderately saline-alkali land in Xintian Village is a coastal saline-alkali land area in my country. The total area of ​​the experimental field for each example or comparative example was 8 mu (approximately 1.3 hectares), with three replicates each, and the average value was taken. Before the experiment, the basic soil sample test results showed that the top 0–20 cm soil was silty loam, with an average total salt content of 4.9 g / kg and a pH value of 8.9.

[0093] Example 2

[0094] This embodiment provides a comprehensive method for improving saline-alkali soil, which specifically includes the following steps:

[0095] (1) Land preparation and fertilization

[0096] Remove debris and weeds from the field to level the field; deep plow the land and let it dry for 5 days, then apply modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the soil surface. The application rate of modified carbon-based organic fertilizer is 150 kg / mu and the application rate of modified carbon-based organic-inorganic compound fertilizer is 50 kg / mu. Then, shallow plow the land.

[0097] Plow and harrow the land to form raised beds, each bed 2.0m wide, with furrows 30cm deep and spaced 30cm apart.

[0098] (2) Seed pretreatment

[0099] Seed selection: Select Suaeda salsa seeds and Sesbania seeds that are free from mold and damage;

[0100] Soak the seeds of Suaeda salsa in 15ppm ABT6 rooting solution for 2 hours, then drain and air dry. Soak the seeds of Sesbania serratifolia in 60℃ hot water, let the water cool naturally, take them out and air dry for 1 day, then soak them in 20ppm ABT6 rooting solution for 6 hours, and then air dry.

[0101] (3) Suaeda salsa cultivation

[0102] Sowing: On April 13, 2022, Suaeda salsa seeds were sown. When sowing, the seeds were sprayed with a 300-fold diluted bacterial solution (10L / mu). Then, the seeds were mixed with fine soil and sown on the surface of the flat beds. The sowing rate of Suaeda salsa seeds was 2kg / mu.

[0103] Harvesting: Harvest on June 25th using a self-propelled combine harvester. The removed Suaeda salsa can be used as forage or for producing lick bricks, depending on demand.

[0104] (4) Sesbania planting

[0105] The planting time for sesame seeds is July 5th. The planting method is row sowing with a row spacing of 50cm and a sowing rate of 5kg / mu. After sowing, apply 5L of bacterial solution per mu with irrigation water.

[0106] Harvesting: Harvested on August 20th, the sesame plants reached a height of 1.3m, with a stubble height of 50cm. The harvested sesame plants were evenly spread between the rows of sesame plants.

[0107] Turning and returning to the field: On October 9, when the sesbania is in full bloom, corn stalk crushing and returning machinery is used to crush the sesbania to a length of 6cm. A reversible plow is then used for deep turning, with a turning depth of 30cm.

[0108] Comparative Example 2

[0109] Same as Example 2, except that only Suaeda salsa is planted, and the specific method is as follows:

[0110] (1) Land preparation and fertilization

[0111] Remove debris and weeds from the field to level the field; deep plow the land and let it dry for 5 days, then apply modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the soil surface. The application rate of modified carbon-based organic fertilizer is 150 kg / mu and the application rate of modified carbon-based organic-inorganic compound fertilizer is 50 kg / mu. Then, shallow plow the land.

[0112] Plow and harrow the land to form raised beds, each bed 2.0m wide, with furrows 30cm deep and spaced 30cm apart.

[0113] (2) Seed pretreatment

[0114] Seed selection: Select Suaeda salsa seeds that are free from mold and damage;

[0115] Soak the Suaeda salsa seeds in 15ppm ABT6 rooting solution for 2 hours, then drain and air dry the seeds.

[0116] (3) Suaeda salsa cultivation

[0117] Sowing: On April 13, 2022, Suaeda salsa seeds were sown. When sowing, the seeds were sprayed with a 300-fold diluted bacterial solution (10L / mu). Then, the seeds were mixed with fine soil and sown on the surface of the flat beds. The sowing rate of Suaeda salsa seeds was 2kg / mu.

[0118] Harvesting: Harvest on June 25th using a self-propelled combine harvester. The removed Suaeda salsa can be used as forage or for producing lick bricks, depending on demand.

[0119] Detection indicators and results

[0120] In Example 2, after returning sesame to the field, and in Comparative Example 2, after harvesting Suaeda salsa, soil samples were collected from 0 to 20 cm depths to test soil salinity and organic matter content. The results are shown in Table 2.

[0121] Table 2 shows the results of soil salinity and organic matter content measurements in the examples and comparative examples.

[0122] deal with Salt content (g / kg) pH value Basicity (%) Organic matter (g / kg) Comparative Example 2 (Suaeda salsa) 4.3 8.4 14.5 12.2 Example 2 (Suaeda salsa + Guava) 3.6 8.1 12.8 13.8

[0123] As can be seen from Table 2, the rotation of Suaeda salsa and Sesbania serratifolia according to the method of Example 2 of the present invention resulted in a 16.3% reduction in total soil salinity, a 0.3-unit reduction in pH value, and an 11.7-percentage-point reduction in alkalinity compared to Comparative Example 2 which only planted Suaeda salsa. The soil organic matter content increased by 13.1%, indicating that the method of the present invention can effectively improve saline-alkali soil.

[0124] Example 3 and Comparative Example 3 of this invention relate to the improvement of severely saline-alkali land. Both were conducted from April 2020 to October 2021 in severely saline-alkali land in Zhonghaibin Village, Leting County, Tangshan City, Hebei Province. This severely saline-alkali land in Zhonghaibin Village is a coastal saline-alkali land area in my country. The total area of ​​the experimental field for each example or comparative example was 8 mu (approximately 1.33 hectares), with three replicates each, and the average value was taken. Before the experiment, the basic soil sample test results showed that the top 0–20 cm soil was silty loam, with an average total salt content of 6.4 g / kg and a pH value of 9.3.

[0125] Example 3

[0126] This embodiment provides a comprehensive method for improving saline-alkali soil, which specifically includes the following steps:

[0127] (1) Land preparation and fertilization

[0128] Remove debris and weeds from the field to level the field; deep plow the land and let it dry for 4 days, then apply modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the soil surface, with the amount of modified carbon-based organic fertilizer applied being 100 kg / mu and the amount of modified carbon-based organic-inorganic compound fertilizer applied being 100 kg / mu, and then shallow plow.

[0129] Plow and harrow the land to form raised beds, each 1.5m wide, with furrows 30cm deep and 35cm apart.

[0130] (2) Seed pretreatment

[0131] Seed selection: Select Suaeda salsa seeds and Sesbania seeds that are free from mold and damage;

[0132] Soak the seeds of Suaeda salsa in 15ppm ABT6 rooting solution for 2 hours, then drain and air dry them. Soak the seeds of Sesbania serratifolia in 60℃ hot water, let the water cool naturally, take them out and air dry for 1 day, then soak them in 25ppm ABT6 rooting solution for 7 hours, and then air dry them.

[0133] (3) Suaeda salsa cultivation

[0134] Sowing: On April 10, 2022, Suaeda salsa seeds were sown. When sowing, the seeds were sprayed with a 250-fold diluted bacterial solution (10L / mu). The seeds were then mixed with fine soil and sown on the surface of the raised beds. The sowing rate of Suaeda salsa seeds was 1kg / mu.

[0135] Harvesting: Harvest on June 25th using a self-propelled combine harvester. The removed Suaeda salsa can be used as forage or for producing lick bricks, depending on demand.

[0136] (4) Sesbania planting

[0137] The planting time for sesame seeds is July 5th. The planting method is row sowing with a row spacing of 50cm and a sowing rate of 3kg / mu. After sowing, apply 10L of bacterial solution per mu with irrigation water.

[0138] Harvesting: Harvested on August 20th, the sesame plants reached a height of 1.5m, with a stubble height of 60cm. The harvested sesame plants were evenly spread between the rows of sesame plants.

[0139] Turning and returning to the field: On October 9, when the sesbania is in full bloom, corn stalk crushing and returning machinery is used to crush the sesbania to a length of 6cm. A reversible plow is then used for deep turning, with a turning depth of 30cm.

[0140] Comparative Example 3

[0141] Same as Example 3, except that only Suaeda salsa is planted, and the specific method is as follows:

[0142] (1) Land preparation and fertilization

[0143] Remove debris and weeds from the field to level the field; deep plow the land and let it dry for 4 days, then apply modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer to the soil surface, with the amount of modified carbon-based organic fertilizer applied being 100 kg / mu and the amount of modified carbon-based organic-inorganic compound fertilizer applied being 100 kg / mu, and then shallow plow.

[0144] Plow and harrow the land to form raised beds, each 1.5m wide, with furrows 30cm deep and 35cm apart.

[0145] (2) Seed pretreatment

[0146] Seed selection: Select Suaeda salsa seeds that are free from mold and damage;

[0147] Soak the Suaeda salsa seeds in 15ppm ABT6 rooting solution for 2 hours, then drain and air dry the seeds.

[0148] (3) Suaeda salsa cultivation

[0149] Sowing: On April 10, 2022, Suaeda salsa seeds were sown. When sowing, the seeds were sprayed with a 250-fold diluted bacterial solution (10L / mu). The seeds were then mixed with fine soil and sown on the surface of the raised beds. The sowing rate of Suaeda salsa seeds was 1kg / mu.

[0150] Harvesting: Harvest on June 25th using a self-propelled combine harvester. The removed Suaeda salsa can be used as forage or for producing lick bricks, depending on demand.

[0151] Detection indicators and results

[0152] In Example 3, after returning sesame to the field, and in Comparative Example 3, after harvesting Suaeda salsa, soil samples were collected from 0 to 20 cm depths to test soil salinity and organic matter content. The results are shown in Table 3.

[0153] Table 3. Results of soil salinity and organic matter content measurements in the examples and comparative examples.

[0154] deal with Salt content (g / kg) pH value Basicity (%) Organic matter (g / kg) Comparative Example 3 (Suaeda salsa) 5.7 8.8 17.5 12.8 Example 3 (Suaeda salsa + Guava) 4.5 8.3 15.8 14.6

[0155] As can be seen from Table 3, when Suaeda salsa and Sesbania serratifolia are rotated according to the method of Example 3 of the present invention, compared with Comparative Example 3 which only planted Suaeda salsa, the total soil salinity decreased by 21.1%, the pH value decreased by 0.5 units, and the alkalinity decreased by 9.7 percentage points; the soil organic matter content increased by 14.1%, indicating that the method of the present invention can effectively improve saline-alkali soil.

[0156] Comparative Example 4

[0157] Same as Example 1, except that the step of fertilization in step (1) is omitted. That is, step (1) is: remove debris and weeds from the field to make the field level; deep plow the land, let it dry for 5 days, then plow and harrow it to make it into ridges with a ridge width of 1.5m, a ditch depth of 30cm, and a ditch spacing of 35cm.

[0158] Comparative Example 5

[0159] Same as Example 1, except that step (1) is:

[0160] Remove debris and weeds from the field to level the field; deeply plow the land and let it dry for 5 days, then apply modified carbon-based organic fertilizer to the soil surface at a rate of 300 kg / mu.

[0161] Plow and harrow the land to form raised beds, each 1.5m wide, with furrows 30cm deep and 35cm apart.

[0162] Comparative Example 6

[0163] Same as Example 1, except that step (1) is:

[0164] Remove debris and weeds from the field to level the field; deep plow the land and let it dry for 5 days, then apply modified carbon-based organic-inorganic compound fertilizer to the soil surface at a rate of 50 kg / mu, and then perform shallow plowing.

[0165] Plow and harrow the land to form raised beds, each 1.5m wide, with furrows 30cm deep and 35cm apart.

[0166] Detection indicators and results

[0167] In Example 1, after returning sesame to the field, soil samples were collected from 0 to 20 cm depth after harvesting Suaeda salsa in Comparative Examples 4 and 6. Soil salinity and organic matter content were tested, and the results are shown in Table 4.

[0168] Table 4 shows the results of soil salinity and organic matter content measurements in the examples and comparative examples.

[0169] deal with Salt content (g / kg) pH value Basicity (%) Organic matter (g / kg) Example 1 4.2 8.1 15.4 15.2 Comparative Example 4 6.3 9.1 19.8 12.1 Comparative Example 5 4.8 8.5 16.3 14.5 Comparative Example 6 4.7 8.6 16.6 14.1

[0170] As can be seen from Table 4, the reason for the decreased improvement effect of Comparative Example 4 compared with Example 1 is that no soil improvement was performed; the modified carbon-based organic-inorganic compound fertilizer in Comparative Example 5 is a slow-release fertilizer that can promote crop growth. Without its addition, crop growth is slower, especially the biomass of sesbania. Comparative Example 6 did not add modified carbon-based organic fertilizer. This fertilizer is mainly used to improve soil structure and promote salt excretion in saline-alkali land. With the reduction of the addition of modified carbon-based organic fertilizer, the soil salinity improvement effect was significantly reduced.

[0171] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for comprehensive improvement of saline soil, characterized in that, The steps of applying modified carbon-based organic fertilizer and modified carbon-based organic-inorganic compound fertilizer on the surface of saline-alkali soil, and then planting Suaeda salsa and Sesbania grandiflora are included. The planting time of Suaeda salsa is in the middle and late April, and the harvesting time is in the middle and early June. The planting time of Sesbania grandiflora is in the early and middle July, and the cutting is performed when the height of Sesbania grandiflora reaches 1.3-1.5 m, and the stubble height is 50-60 cm. The raw materials of the modified carbon-based organic fertilizer include 55 parts of matured manure, 15 parts of modified biomass carbon, 10 parts of potassium humate, 20 parts of phosphorus gypsum, 0.2 parts of polyglutamic acid, and 3 parts of attapulgite powder in terms of mass fraction. The raw materials of the modified carbon-based organic-inorganic compound fertilizer include 34 parts of matured manure, 10 parts of vinasse, 10 parts of modified biomass carbon, 12 parts of urea, 8 parts of ammonium sulfate, 10 parts of potassium sulfate, 15 parts of monoammonium phosphate, 1 part of calcium magnesium phosphate fertilizer, 0.1 part of manganese sulfate, 0.5 part of amino acid chelated iron, 0.05 part of amino acid chelated zinc, 0.2 part of borax, and 3 parts of attapulgite powder in terms of mass fraction.

2. The method of comprehensive improvement of saline soil according to claim 1, characterized in that, The mass fraction of organic matter in the modified carbon-based organic fertilizer is greater than or equal to 30%, and the mass fraction of modified biomass carbon is greater than or equal to 20%.

3. The method of comprehensive improvement of saline soil according to claim 1, characterized in that, The mass ratio of N, P2O5 and K2O in the modified carbon-based organic-inorganic compound fertilizer is 7:5:3, the mass fraction of organic matter is greater than or equal to 20%, and the mass fraction of modified biomass carbon is greater than or equal to 15%.

4. The method of comprehensive improvement of saline soil according to claim 1, characterized in that, The application amount of the modified carbon-based organic fertilizer is 100-300 kg per mu, and the application amount of the modified carbon-based organic-inorganic compound fertilizer is 50-100 kg per mu.

5. The method of comprehensive improvement of saline soil according to claim 1, characterized in that, The seeding amount of Suaeda salsa is 1-3 kg per mu, and the seeding amount of Sesbania grandiflora is 3-6 kg per mu.

6. The method of comprehensive improvement of saline soil according to claim 1, characterized in that, The cut part of Sesbania grandiflora is laid flat in the row of Sesbania grandiflora.

7. The method of comprehensive improvement of saline soil according to claim 1, characterized in that, The cut part of Sesbania grandiflora is laid flat in the row of Sesbania grandiflora. The cut part of Sesbania grandiflora is laid flat in the row of Sesbania grandiflora.