A method for improving afforestation by retaining water in arid soil

Abstract

The present invention relates to the field of forestry planting technology, and more particularly to a method for improving water conservation and afforestation in arid soil. The afforestation method comprises the following steps: (1) preparing a soil conditioner; (2) preparing a water-retaining material; (3) planting seedlings for afforestation; and (4) performing routine management after the seedlings are planted. Utilizing the method of the present invention for afforestation can effectively improve the survival rate of the afforestation.

Description

Technical Field

[0001] The invention relates to the technical field of forestry planting, and in particular to a method for improving and afforestation through water conservation in arid soil. Background Art

[0002] Arid and semi-arid regions occupy a significant area worldwide. The soils in these areas generally have poor water-holding capacity, primarily due to their sandy texture, large soil particles, and large inter-particle pores. This results in water easily leaching and escaping, making it difficult for plants to retain water for long periods of time. Furthermore, the soils in arid regions are deficient in organic matter. Due to harsh climatic conditions and limited vegetation cover, organic matter decomposes slowly, resulting in a lack of organic components that can improve soil structure and enhance water and fertilizer retention. Traditional afforestation methods face numerous challenges when implemented in arid regions. First, simple pit planting methods, which fail to effectively improve the soil, create a harsh soil environment for the roots of newly planted seedlings, leading to rapid water loss and difficulty in establishing and surviving, resulting in extremely low survival rates. Second, even with irrigation, high evaporation rates in arid environments waste significant amounts of water resources and fail to fundamentally address the soil's insufficient water-retention capacity, posing serious challenges to the long-term sustainability of afforestation projects. Therefore, developing an afforestation method that can effectively enhance the water-retention capacity of arid soils and improve seedling survival rates is an urgent technical challenge. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the present invention proposes a method for improving and afforestation of arid soil by retaining water.

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for improving and afforestation of arid soil by retaining water comprises the following steps:

[0006] (1) Preparation of soil improvement materials:

[0007] (11) 4-7 parts of Acanthopanax senticosus, 3-5 parts of Corn Silk, and 6-9 parts of Prunella Vulgaris were mixed, dried at 50°C, crushed through an 80-100 mesh sieve, and mixed with deionized water at a material-liquid ratio of 1 g:20 mL. The mixture was sterilized at 121°C for 20 min, inoculated with activated Lactobacillus plantarum after cooling, cultured with shaking at 30°C and 150-180 rpm for 72 h, centrifuged at 8000 rpm for 8-12 min, and the supernatant was concentrated under reduced pressure to 20% of the original volume and freeze-dried to obtain a fermentation extract.

[0008] (12) Calcium chloride was added to a 1% w / v acetic acid solution, and chitosan was added and stirred to obtain a calcium chloride-chitosan acetic acid mixed solution; a 3% w / v sodium alginate solution was prepared, and the fermentation extract obtained in step (11) was added and stirred to obtain a calcium chloride-chitosan acetic acid mixed solution dropwise, and the mixture was stirred at 200-300 rpm for 10 min, allowed to stand for 2 h, filtered, and the filter cake was washed with deionized water and dried at 50°C to obtain a soil improvement material;

[0009] (2) Preparation of water-retaining materials:

[0010] (21) Place 2 mol / L sodium hydroxide solution in a 0°C alcohol bath for cooling, add 3-aminophenylboronic acid and mix well, add acryloyl chloride dropwise, react at 25°C for 5 h after the addition is complete, adjust the pH to 1-1.2 with 1 mol / L HCl, filter, wash the precipitate with cold water, dissolve it in ethyl acetate extraction phase, wash it with 1 mol / L HCl solution and saturated NaCl solution in sequence, dry the organic layer with anhydrous Na2SO4, remove Na2SO4 by filtration, remove the ethyl acetate solvent by rotary evaporation, recrystallize it with deionized water, and dry it in vacuo to obtain acrylamidephenylboronic acid;

[0011] (22) The straw was washed and dried, sheared and crushed to pass through a 60-mesh sieve, heated to 550°C at a rate of 10°C / min in a vacuum tube furnace under N2 atmosphere, kept warm for 2 h, cooled to room temperature, mixed with 0.15 g / mL KOH solution at a ratio of 1 g:1 mL, dried at 80°C, placed in a vacuum tube furnace and heated to 650°C in N2 atmosphere, kept warm for 2 h, cooled to room temperature, and washed with 0.5 mol / L hydrochloric acid solution and deionized water in sequence until neutral, vacuum dried, and ground to obtain straw charcoal powder;

[0012] (23) The straw charcoal powder obtained in step (22) was added to a 10 mol / L nitric acid solution, ultrasonicated at 300W for 6-10 min, stirred at 90°C in the dark for 5-6 h, cooled to room temperature and filtered, the filter cake was washed with deionized water, vacuum-dried at 60°C, mixed with NMP, and 1 mol / L HNO3 solution and vinyltriethoxysilane (VTES) were added dropwise under 300W ultrasonication, and ultrasonication was continued for 10 min. The mixture was stirred at 90°C in the dark for 24 h, cooled to room temperature, filtered, the filter cake was washed with ethanol and deionized water, and vacuum-dried at 60°C to obtain a modified straw charcoal material;

[0013] (24) Under nitrogen atmosphere, the acrylamide phenylboronic acid obtained in step (21), the modified straw charcoal material obtained in step (23), dimethylaminopropyl acrylamide (DMAPAA), and acrylamide (AM) were added to DMSO and mixed evenly, and initiator AIBN was added. The mixture was reacted at 60 °C for 12 h, cooled to room temperature, filtered, washed with deionized water, and freeze-dried;

[0014] (25) 0.1 mmol / mL Na2CO3 solution and 0.2 mmol / mL NaHCO3 solution were mixed in a ratio of 1:4 (v:v) to obtain a buffer solution, sodium alginate was added to the buffer solution and mixed to obtain a mixed solution A, the freeze-dried product obtained in step (24) was mixed with the buffer solution to obtain a mixed solution B, the mixed solution A was added to the mixed solution B, the mixture was shaken at 100-150 rpm for 12 h, dried at 40°C, and freeze-dried to obtain a water-retaining material;

[0015] (3) Planting of seedlings and afforestation:

[0016] (31) After the soil thaws in the spring, evenly spread the soil improvement materials on the surface of the afforestation area, plow the land to mix the soil improvement materials with the afforestation soil, then dig planting pits, mix the water-retaining materials with the soil, soak them with water, and lay them at the bottom of each planting pit;

[0017] (32) Select 5-year-old Platycladus orientalis seedlings, remove the overlong and damaged roots, retain the main root length of 20-30 cm, the lateral root length of 10-15 cm, trim the excess branches and leaves, and soak the seedling roots in rooting nutrient solution for 1-2 hours;

[0018] (33) Place the soaked seedling in the center of the planting pit and backfill the soil. When the backfill reaches half the depth of the planting pit, lift the seedling. Continue backfilling the soil and compacting it layer by layer. Spread the loose soil and pile it into a 10-15 cm mountain-shaped mound.

[0019] (4) Carry out routine management after seedling planting: irrigation, weeding, fertilization, and pest and disease control according to conventional methods in this field.

[0020] Furthermore, in step (11), the Lactobacillus plantarum was purchased from China General Microorganism Culture Collection Center with a number of CGMCC 1.572.

[0021] Furthermore, in step (11), the inoculation amount of the plant lactobacillus is 1×10 5 CFU / mL.

[0022] Furthermore, in step (12), in the calcium chloride-chitosan acetic acid mixed solution, the mass volume fraction of calcium chloride is 4% w / v, and the mass volume fraction of chitosan is 0.3% w / v.

[0023] Furthermore, in step (12), the mass ratio of calcium chloride to sodium alginate is 2:1.

[0024] Furthermore, in step (12), the mass ratio of the fermentation extract to sodium alginate is 1:2-3.

[0025] Furthermore, in step (21), the ratio of the sodium hydroxide solution, 3-aminophenylboronic acid and acryloyl chloride is 20 mL:10 mmol:20 mmol.

[0026] Furthermore, in step (22), the straw is straw of crops such as rice, wheat, sorghum, and rapeseed.

[0027] Furthermore, in step (23), the ratio of the straw charcoal powder to the 10 mol / L nitric acid solution is 1 g:10-15 mL.

[0028] Furthermore, in step (23), the ratio of the straw charcoal powder to NMP is 1 g: 25-30 mL.

[0029] Furthermore, in step (23), the volume ratio of NMP, 1 mol / L HNO3 solution and VTES is 50-60:1:5-6.

[0030] Furthermore, in step (24), the mass ratio of the acrylamide phenylboric acid, the modified straw charcoal material, the dimethylaminopropyl acrylamide, and the acrylamide is 2-3:8-12:2-3:5-7.

[0031] Furthermore, in step (24), the ratio of the modified straw charcoal material to DMSO is 1 g:100 mL.

[0032] Furthermore, in step (24), the amount of AIBN used is 1-1.5 wt % of acrylamide.

[0033] Furthermore, in step (25), in the mixed solution A, the mass concentration of sodium alginate in the buffer solution is 20-30 mg / mL.

[0034] Furthermore, in step (25), in the mixed solution B, the mass concentration of the freeze-dried product in the buffer solution is 0.1 g / mL.

[0035] Furthermore, in step (25), the mass ratio of the sodium alginate to the freeze-dried product is 1:10-15.

[0036] Furthermore, in step (31), the amount of soil improvement material applied is 10-15 kg / m2 , the tillage depth is 30-50 cm.

[0037] Furthermore, in step (31), the planting pit has a row spacing of 2×3 m, a planting pit depth of 40-50 cm, and a diameter of 40-50 cm.

[0038] Furthermore, in step (31), the mass ratio of the water-retaining material to the soil is 1:20-30.

[0039] Furthermore, in step (31), the amount of the water-retaining material is 20 g / planting pit.

[0040] Furthermore, in step (32), the rooting nutrient solution is prepared by uniformly mixing 500 mg of magnesium sulfate, 3 mg of manganese sulfate, 0.05 mg of copper sulfate, 0.2 mg of zinc sulfate, 2 mg of boric acid, 500 mg of calcium nitrate, 3 g of indoleacetic acid, 2 g of naphthaleneacetic acid, and 20 g of glucose, and adding water to make up to 1 L to obtain the rooting nutrient solution.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention provides a method for improving water conservation and afforestation in arid soils. From soil improvement and water conservation material preparation to seedling planting and management, the method solves the problem of afforestation in arid areas and has significant effects in improving soil water and fertilizer retention capacity and increasing seedling survival rate. In the preparation of soil improvement materials, the present invention ferments natural raw materials such as Acanthopanax senticosus, Corn Silk, and Prunella Vulgaris by Lactobacillus plantarum to generate humic acid precursors, thereby obtaining a fermentation extract rich in active ingredients such as amino acids and organic acids. Humic acid can adsorb soil particles to form a granular structure, reduce the proportion of macropores, and reduce water osmotic loss. At the same time, functional groups such as hydroxyl and carboxyl groups contained in the humic acid bind to water molecules through hydrogen bonds and ionic bonds, thereby improving the soil's water holding capacity. After fermentation by Lactobacillus plantarum, the bioavailability of active ingredients can be improved, the total nitrogen and organic matter content in the soil can be increased, and a continuous nutrient supply can be provided for the seedlings. The present invention uses chitosan and sodium alginate to form a cross-linked network, encapsulates the fermentation extract, and forms a slow-release carrier. The amino groups of chitosan and the carboxyl groups of sodium alginate are ionically bonded to slowly release the active ingredient in the soil, prolonging the duration of the improvement effect, improving soil fertility, and creating a good soil environment for the growth of seedlings. The present invention uses discarded crop straw as raw material to prepare activated carbon, turning waste into treasure. The activated carbon is rich in pores after being activated by potassium hydroxide. It is modified using a silane coupling agent so that double bond groups are grafted on the surface, which is conducive to subsequent reactions. The present invention uses 3-aminophenylboronic acid and acryloyl chloride to synthesize acrylamidephenylboronic acid containing double bonds and phenylboronic acid groups. The polymer is polymerized with modified straw carbon material, DMAPAA, and AM under the action of an initiator. The formed polymer is rich in amide groups and can improve water absorption and water retention properties. The phenylboronic acid groups are cross-linked with sodium alginate through a buffer system to form a three-dimensional gel network, which increases water holding rate and limits water loss. At the same time, it synergizes with the pore structure of the modified straw carbon to effectively improve the water retention performance of the water-retaining material. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 This is a scanning electron microscope image of the water-retaining material obtained in Example 1 of the present invention;

[0045] Figure 2 The water retention performance of the water retention materials described in Examples 1-3 and Comparative Examples 3-5 of the present invention;

[0046] Figure 3 The soil improvement effect of the afforestation method described in Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0047] Figure 4 It is the afforestation survival rate of the afforestation methods described in Examples 1-3 of the present invention and Comparative Examples 1-5. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific examples, but the present invention is not limited to the following examples. It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention were purchased through commercial channels.

[0049] Example 1: A method for improving water conservation and afforestation in arid soil, comprising the following steps:

[0050] (1) Preparation of soil improvement materials:

[0051] (11) Mix 7 g of Acanthopanax senticosus, 5 g of corn silk, and 9 g of Prunella vulgaris, dry them at 50 °C, grind them through a 100-mesh sieve, mix them with deionized water at a material-liquid ratio of 1 g:20 mL, sterilize them at 121 °C for 20 min, cool them, and sieve them at 1 × 10 5 The activated Lactobacillus plantarum was inoculated with an inoculum size of 100 CFU / mL and cultured at 30°C, 180 rpm, and shaken for 72 h. The supernatant was centrifuged at 8000 rpm for 12 min, and the supernatant was concentrated under reduced pressure to 20% of the original volume and freeze-dried to obtain the fermentation extract. Lactobacillus plantarum was purchased from the China General Microbiological Culture Collection Center with the number CGMCC 1.572.

[0052] (12) Add 6 g of calcium chloride to 150 mL of 1% w / v acetic acid solution, stir evenly, then add 0.45 g of chitosan and stir evenly to obtain a calcium chloride-chitosan acetic acid mixed solution; prepare a 3% w / v sodium alginate solution with 3 g of sodium alginate, add 1 g of the fermentation extract obtained in step (11) and stir evenly, add dropwise to the calcium chloride-chitosan acetic acid mixed solution, stir at 300 rpm for 10 min, let stand for 2 h, filter, wash the filter cake with deionized water, and dry at 50°C to obtain a soil improvement material;

[0053] (2) Preparation of water-retaining materials:

[0054] (21) Place 20 mL of 2 mol / L sodium hydroxide solution in a 0°C alcohol bath for cooling, add 10 mmol of 3-aminophenylboronic acid and mix well, add 20 mmol of acryloyl chloride dropwise, react at 25°C for 5 h after the addition is complete, adjust the pH to 1.2 with 1 mol / L HCl, filter, wash the precipitate with cold water, dissolve it in ethyl acetate, wash it with 1 mol / L HCl solution and saturated NaCl solution in sequence, dry the organic layer with anhydrous Na2SO4, remove Na2SO4 by filtration, remove the ethyl acetate solvent by rotary evaporation, recrystallize it with deionized water, and dry it in vacuo to obtain acrylamidephenylboronic acid;

[0055] (22) The wheat straw was washed and dried, sheared and crushed to pass through a 60-mesh sieve, heated to 550°C at a rate of 10°C / min in a vacuum tube furnace under N2 atmosphere, kept warm for 2 h, cooled to room temperature, mixed with 0.15 g / mL KOH solution at a ratio of 1 g:1 mL, dried at 80°C, heated to 650°C in a vacuum tube furnace under N2 atmosphere, kept warm for 2 h, cooled to room temperature, and washed with 0.5 mol / L hydrochloric acid solution and deionized water in sequence until neutral, vacuum dried, and ground to obtain straw charcoal powder;

[0056] (23) 10 g of the straw charcoal powder obtained in step (22) was added to 150 mL of 10 mol / L nitric acid solution, ultrasonicated at 300W for 10 min, stirred and reacted at 90°C in the dark for 6 h, cooled to room temperature and filtered, the filter cake was washed with deionized water, vacuum-dried at 60°C, mixed with 300 mL of NMP, and dropwise added with 5 mL of 1 mol / L HNO3 solution and 30 mL of vinyltriethoxysilane (VTES) under 300W ultrasonication, and ultrasonicated for 10 min. Stirred and reacted at 90°C in the dark for 24 h, cooled to room temperature, filtered, the filter cake was washed with ethanol and deionized water, and vacuum-dried at 60°C to obtain a modified straw charcoal material;

[0057] (24) Under nitrogen atmosphere, 3 g of acrylamide phenylboronic acid obtained in step (21), 12 g of modified straw carbon material obtained in step (23), 3 g of dimethylaminopropyl acrylamide, and 7 g of acrylamide were added to 1200 mL of DMSO and mixed evenly. 0.105 g of initiator AIBN was added and reacted at 60 °C for 12 h. The mixture was cooled to room temperature, filtered, washed with deionized water, and freeze-dried.

[0058] (25) 0.1 mmol / mL Na2CO3 solution and 0.2 mmol / mL NaHCO3 solution were mixed in a ratio of 1:4 (v:v) to obtain a buffer solution. 1.5 g of sodium alginate was added to 50 mL of the buffer solution and mixed to obtain a mixed solution A. 22.5 g of the freeze-dried product obtained in step (24) was mixed with 225 mL of the buffer solution to obtain a mixed solution B. The mixed solution A was added to the mixed solution B, shaken at 150 rpm for 12 h, dried at 40°C, and freeze-dried to obtain a water-retaining material. The scanning electron microscope image is shown in FIG. Figure 1 As shown;

[0059] (3) Planting of seedlings and afforestation:

[0060] (31) After the soil thaws in spring, the soil improvement material prepared in step (1) is evenly spread on the surface of the afforestation land. The soil improvement material is tilled to mix evenly with the afforestation land. The application rate of the soil improvement material is 15 kg / m 2 , the tillage depth is 50 cm, and then the planting pits are dug, the planting pit spacing is 2×3 m, the planting pit depth is 50 cm, and the diameter is 50 cm. The water-retaining material prepared according to the method in step (2) is mixed with the soil at a mass ratio of 1:30, and then soaked with water and laid at the bottom of each planting pit. The amount of water-retaining material used is 20 g / planting pit;

[0061] (32) Mix 500 mg of magnesium sulfate, 3 mg of manganese sulfate, 0.05 mg of copper sulfate, 0.2 mg of zinc sulfate, 2 mg of boric acid, 500 mg of calcium nitrate, 3 g of indoleacetic acid, 2 g of naphthaleneacetic acid, and 20 g of glucose, and dilute to 1 L with water to obtain a rooting nutrient solution. Select 5-year-old Platycladus orientalis seedlings, remove the overlong and damaged roots, retain the main root length of 30 cm and the lateral root length of 15 cm, trim the excess branches and leaves, and soak the seedling roots in the rooting nutrient solution for 2 h.

[0062] (33) Place the soaked seedling in the center of the planting pit and backfill the soil. When the backfill reaches half the depth of the planting pit, lift the seedling out and continue backfilling the soil and compacting it layer by layer. Spread the loose soil and pile it into a 15 cm mountain-shaped mound.

[0063] (4) Carry out routine management after seedling planting: irrigation, weeding, fertilization, and pest and disease control according to conventional methods in this field.

[0064] Example 2: A method for improving water conservation in arid soil and afforestation, comprising the following steps:

[0065] (1) Preparation of soil improvement materials:

[0066] (11) Mix 4 g of Acanthopanax senticosus, 3 g of corn silk, and 6 g of Prunella vulgaris, dry them at 50 °C, grind them through an 80-mesh sieve, mix them with deionized water at a material-liquid ratio of 1 g:20 mL, sterilize them at 121 °C for 20 min, and cool them to a concentration of 1 × 10 5 The activated Lactobacillus plantarum was inoculated with an inoculum size of 100 CFU / mL and cultured at 30°C, 150 rpm, and shaken for 72 h. The supernatant was centrifuged at 8000 rpm for 8 min, and the supernatant was concentrated under reduced pressure to 20% of the original volume and freeze-dried to obtain the fermentation extract. Lactobacillus plantarum was purchased from the China General Microbiological Culture Collection Center with the number CGMCC 1.572.

[0067] (12) Add 6 g of calcium chloride to 150 mL of 1% w / v acetic acid solution, stir evenly, then add 0.45 g of chitosan and stir evenly to obtain a calcium chloride-chitosan acetic acid mixed solution; use 3 g of sodium alginate to prepare a 3% w / v sodium alginate solution, add 1.5 g of the fermentation extract obtained in step (11) and stir evenly, add dropwise to the calcium chloride-chitosan acetic acid mixed solution, stir at 200 rpm for 10 min, let stand for 2 h, filter, wash the filter cake with deionized water, and dry at 50°C to obtain a soil improvement material;

[0068] (2) Preparation of water-retaining materials:

[0069] (21) Place 20 mL of 2 mol / L sodium hydroxide solution in a 0°C alcohol bath for cooling, add 10 mmol of 3-aminophenylboronic acid and mix well, add 20 mmol of acryloyl chloride dropwise, react at 25°C for 5 h after the addition is complete, adjust the pH to 1 with 1 mol / L HCl, filter, wash the precipitate with cold water, dissolve it in ethyl acetate, wash it with 1 mol / L HCl solution and saturated NaCl solution in sequence, dry the organic layer with anhydrous Na2SO4, remove Na2SO4 by filtration, remove the ethyl acetate solvent by rotary evaporation, recrystallize it with deionized water, and dry it in vacuo to obtain acrylamidephenylboronic acid;

[0070] (22) The rice straw was washed and dried, sheared and crushed to pass through a 60-mesh sieve, heated to 550°C at a rate of 10°C / min in a vacuum tube furnace under N2 atmosphere, kept warm for 2 h, cooled to room temperature, mixed with 0.15 g / mL KOH solution at a ratio of 1 g:1 mL, dried at 80°C, heated to 650°C in a vacuum tube furnace under N2 atmosphere, kept warm for 2 h, cooled to room temperature, and washed with 0.5 mol / L hydrochloric acid solution and deionized water in sequence until neutral, vacuum dried, and ground to obtain straw charcoal powder;

[0071] (23) 10 g of the straw charcoal powder obtained in step (22) was added to 100 mL of 10 mol / L nitric acid solution, ultrasonicated at 300W for 6 min, stirred and reacted at 90°C in the dark for 5 h, cooled to room temperature and filtered, the filter cake was washed with deionized water, vacuum-dried at 60°C, mixed with 250 mL of NMP, and dropwise added with 5 mL of 1 mol / L HNO3 solution and 250 mL of vinyltriethoxysilane (VTES) under 300W ultrasonication, and ultrasonicated for 10 min. Stirred and reacted at 90°C in the dark for 24 h, cooled to room temperature, filtered, the filter cake was washed with ethanol and deionized water, and vacuum-dried at 60°C to obtain a modified straw charcoal material;

[0072] (24) Under nitrogen atmosphere, 2 g of acrylamide phenylboronic acid obtained in step (21), 8 g of modified straw carbon material obtained in step (23), 2 g of dimethylaminopropyl acrylamide, and 5 g of acrylamide were added to 800 mL of DMSO and mixed evenly. 0.05 g of initiator AIBN was added and reacted at 60 °C for 12 h. The mixture was cooled to room temperature, filtered, washed with deionized water, and freeze-dried.

[0073] (25) 0.1 mmol / mL Na2CO3 solution and 0.2 mmol / mL NaHCO3 solution were mixed in a ratio of 1:4 (v:v) to obtain a buffer solution. 2 g of sodium alginate was added to 100 mL of the buffer solution and mixed to obtain a mixed solution A. 20 g of the freeze-dried product obtained in step (24) was mixed with 200 mL of the buffer solution to obtain a mixed solution B. The mixed solution A was added to the mixed solution B, shaken at 100 rpm for 12 h, dried at 40°C, and freeze-dried to obtain a water-retaining material.

[0074] (3) Planting of seedlings and afforestation:

[0075] (31) After the soil thaws in spring, the soil improvement material prepared in step (1) is evenly spread on the surface of the afforestation land. The soil improvement material is tilled to mix evenly with the afforestation land. The application rate of the soil improvement material is 10 kg / m 2 , the tillage depth is 30 cm, and then the planting pits are dug, the planting pit spacing is 2×3 m, the planting pit depth is 40 cm, and the diameter is 40 cm. The water-retaining material prepared in step (2) is mixed with the soil at a mass ratio of 1:20, and then soaked with water, and laid at the bottom of each planting pit. The amount of water-retaining material used is 20 g / planting pit;

[0076] (32) Mix 500 mg of magnesium sulfate, 3 mg of manganese sulfate, 0.05 mg of copper sulfate, 0.2 mg of zinc sulfate, 2 mg of boric acid, 500 mg of calcium nitrate, 3 g of indoleacetic acid, 2 g of naphthaleneacetic acid, and 20 g of glucose, and dilute to 1 L with water to obtain a rooting nutrient solution. Select 5-year-old Platycladus orientalis seedlings, remove the overlong and damaged roots, retain the main root length of 20 cm and the lateral root length of 10 cm, trim the excess branches and leaves, and soak the seedling roots in the rooting nutrient solution for 1 h.

[0077] (33) Place the soaked seedling in the center of the planting pit and backfill the soil. When the backfill reaches half the depth of the planting pit, lift the seedling out and continue backfilling the soil and compacting it layer by layer. Spread the loose soil and pile it into a 10 cm mountain-shaped mound.

[0078] (4) Carry out routine management after seedling planting: irrigation, weeding, fertilization, and pest and disease control according to conventional methods in this field.

[0079] Example 3: A method for improving water conservation in arid soil and afforestation, comprising the following steps:

[0080] (1) Preparation of soil improvement materials:

[0081] (11) Mix 6 g of Acanthopanax senticosus, 4 g of corn silk, and 8 g of Prunella vulgaris, dry them at 50 °C, grind them through a 90-mesh sieve, mix them with deionized water at a material-liquid ratio of 1 g:20 mL, sterilize them at 121 °C for 20 min, and cool them to a concentration of 1 × 10 5 The activated Lactobacillus plantarum was inoculated with an inoculum size of 100 CFU / mL and cultured at 30°C, 160 rpm, and shaken for 72 h. The supernatant was centrifuged at 8000 rpm for 10 min, and the supernatant was concentrated to 20% of the original volume under reduced pressure and freeze-dried to obtain the fermentation extract. Lactobacillus plantarum was purchased from the China General Microbiological Culture Collection Center with the number CGMCC 1.572.

[0082] (12) Add 6 g of calcium chloride to 150 mL of 1% w / v acetic acid solution, stir evenly, then add 0.45 g of chitosan and stir evenly to obtain a calcium chloride-chitosan acetic acid mixed solution; use 3 g of sodium alginate to prepare a 3% w / v sodium alginate solution, add 1.2 g of the fermentation extract obtained in step (11) and stir evenly, add dropwise to the calcium chloride-chitosan acetic acid mixed solution, stir at 250 rpm for 10 min, let stand for 2 h, filter, wash the filter cake with deionized water, and dry at 50°C to obtain a soil improvement material;

[0083] (2) Preparation of water-retaining materials:

[0084] (21) Place 20 mL of 2 mol / L sodium hydroxide solution in a 0°C alcohol bath for cooling, add 10 mmol of 3-aminophenylboronic acid and mix well, add 20 mmol of acryloyl chloride dropwise, react at 25°C for 5 h after the addition is complete, adjust the pH to 1.1 with 1 mol / L HCl, filter, wash the precipitate with cold water, dissolve it in ethyl acetate, wash it with 1 mol / L HCl solution and saturated NaCl solution in sequence, dry the organic layer with anhydrous Na2SO4, remove Na2SO4 by filtration, remove the ethyl acetate solvent by rotary evaporation, recrystallize it with deionized water, and dry it in vacuo to obtain acrylamidephenylboronic acid;

[0085] (22) The wheat straw was washed and dried, sheared and crushed to pass through a 60-mesh sieve, heated to 550°C at a rate of 10°C / min in a vacuum tube furnace under N2 atmosphere, kept warm for 2 h, cooled to room temperature, mixed with 0.15 g / mL KOH solution at a ratio of 1 g:1 mL, dried at 80°C, heated to 650°C in a vacuum tube furnace under N2 atmosphere, kept warm for 2 h, cooled to room temperature, and washed with 0.5 mol / L hydrochloric acid solution and deionized water in sequence until neutral, vacuum dried, and ground to obtain straw charcoal powder;

[0086] (23) 10 g of the straw charcoal powder obtained in step (22) was added to 120 mL of 10 mol / L nitric acid solution, ultrasonicated at 300 W for 8 min, stirred and reacted at 90 ° C in the dark for 5.5 h, cooled to room temperature and filtered, the filter cake was washed with deionized water, vacuum-dried at 60 ° C, mixed with 280 mL of NMP, and 5 mL of 1 mol / L HNO3 solution and 28 mL of vinyltriethoxysilane (VTES) were added dropwise under 300 W ultrasonication, and ultrasonication was continued for 10 min. The mixture was stirred and reacted at 90 ° C in the dark for 24 h, cooled to room temperature, filtered, the filter cake was washed with ethanol and deionized water, and vacuum-dried at 60 ° C to obtain a modified straw charcoal material;

[0087] (24) Under nitrogen atmosphere, 2.5 g of acrylamide phenylboronic acid obtained in step (21), 10 g of modified straw carbon material obtained in step (23), 2.5 g of dimethylaminopropyl acrylamide, and 6 g of acrylamide were added to 1000 mL of DMSO and mixed evenly. 0.072 g of initiator AIBN was added, and the mixture was reacted at 60 °C for 12 h. The mixture was cooled to room temperature, filtered, washed with deionized water, and freeze-dried.

[0088] (25) 0.1 mmol / mL Na2CO3 solution and 0.2 mmol / mL NaHCO3 solution were mixed in a ratio of 1:4 (v:v) to obtain a buffer solution. 2.5 g of sodium alginate was added to 100 mL of the buffer solution and mixed to obtain a mixed solution A. 30 g of the freeze-dried product obtained in step (24) was mixed with 300 mL of the buffer solution to obtain a mixed solution B. The mixed solution A was added to the mixed solution B, shaken at 120 rpm for 12 h, dried at 40°C, and freeze-dried to obtain a water-retaining material.

[0089] (3) Planting of seedlings and afforestation:

[0090] (31) After the soil thaws in spring, the soil improvement material prepared in step (1) is evenly spread on the surface of the afforestation land. The soil improvement material is tilled to mix evenly with the afforestation land. The application rate of the soil improvement material is 12 kg / m 2 , the tillage depth is 40 cm, and then the planting pits are dug, the planting pit spacing is 2×3 m, the planting pit depth is 45 cm, and the diameter is 45 cm. The water-retaining material prepared according to the method in step (2) is mixed with the soil at a mass ratio of 1:25, and then soaked with water and laid at the bottom of each planting pit. The amount of water-retaining material used is 20 g / planting pit;

[0091] (32) Mix 500 mg of magnesium sulfate, 3 mg of manganese sulfate, 0.05 mg of copper sulfate, 0.2 mg of zinc sulfate, 2 mg of boric acid, 500 mg of calcium nitrate, 3 g of indoleacetic acid, 2 g of naphthaleneacetic acid, and 20 g of glucose, and dilute to 1 L with water to obtain a rooting nutrient solution. Select 5-year-old Platycladus orientalis seedlings, remove the overlong and damaged roots, retain the main root length of 25 cm and the lateral root length of 12 cm, trim the excess branches and leaves, and soak the seedling roots in the rooting nutrient solution for 1.5 h.

[0092] (33) Place the soaked seedling in the center of the planting pit and backfill the soil. When the backfill reaches half the depth of the planting pit, lift the seedling out and continue backfilling the soil and compacting it layer by layer. Spread the loose soil and pile it into a 12 cm mountain-shaped mound.

[0093] (4) Carry out routine management after seedling planting: irrigation, weeding, fertilization, and pest and disease control according to conventional methods in this field.

[0094] The difference between Comparative Example 1 and Example 1 is that the supernatant in step (1) is replaced by a mixed infusion of Acanthopanax senticosus, Corn Silk and Prunella Vulgaris (the Chinese medicine is crushed and sieved, soaked for 1 hour and decocted, boiled and then decocted for 30 minutes, filtered, and the above operation is repeated, and the two infusions are combined).

[0095] The only difference between Comparative Example 2 and Example 1 is that step (2) is not performed and the fermentation extract is directly applied.

[0096] The only difference between Comparative Example 3 and Example 1 is that acrylamide is used instead of acrylamidephenylboric acid.

[0097] The only difference between Comparative Example 4 and Example 1 is that step (25) is not performed.

[0098] The only difference between Comparative Example 5 and Example 1 is that no modified straw charcoal material is added.

[0099] Experimental Example 1: 1 g of the water-retaining material prepared in Examples 1-3 and Comparative Examples 3-5 was mixed evenly with 50 g of dry soil sample, and placed in a PVC tube with filter paper at the bottom. The lower end was sealed with gauze, and a piece of filter paper was placed on the top to disperse the dripped water evenly. Distilled water was slowly added dropwise using an infusion device at room temperature until water seeped out from the bottom. After the water absorption reached saturation, the water holding rate was calculated. The results are as follows: Figure 2 shown.

[0100] Figure 2 The results show that the water retention rates of Examples 1-3 are significantly better than those of Comparative Examples 3-5. In Comparative Example 3, acrylamide is used instead of acrylamidephenylboric acid, which reduces the degree of crosslinking with sodium alginate and reduces the water retention effect. In Comparative Example 2, step (25) is not performed, i.e., no compounding with sodium alginate is performed, and the water retention effect is reduced. In Comparative Example 3, no modified straw carbon material is added, and the water absorption and water retention performance is reduced.

[0101] Experimental Example 2: After 30 days of afforestation according to the methods of Examples 1-3 and Comparative Examples 1-2, rhizosphere soil was collected, air-dried, and then sieved through a 60-mesh sieve. The organic matter was determined by potassium dichromate oxidation-external heating method, and the total nitrogen was determined by Kjeldahl nitrogen determination method. The results are as follows: Figure 3 shown.

[0102] Figure 3 The results showed that the organic matter and total nitrogen contents in the rhizosphere soil of Examples 1-3 were higher than those in Comparative Examples 1-2, indicating that Lactobacillus plantarum fermentation can improve soil fertility and be beneficial to seedling growth. The cross-linking of chitosan and sodium alginate to form a slow-release system can prolong the soil improvement time.

[0103] Experimental Example 3: After the spring afforestation of Examples 1-3 and Comparative Examples 1-5, the afforestation survival rate was investigated one year after afforestation. The results are as follows: Figure 4 shown.

[0104] Figure 4 The results show that compared with comparative examples 1-5, the survival rate of the groups in Examples 1-3 is significantly higher than that in comparative examples 1-5. This shows that the afforestation method of the present invention is beneficial to improving afforestation survival and enhancing the drought resistance of plants.

[0105] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A method for improving afforestation by conserving water in arid soil, characterized in that: The following steps are involved: (1) Preparation of soil improvement materials: (11) 4-7 parts of Acanthopanax senticosus, 3-5 parts of Corn Silk, and 6-9 parts of Prunella Vulgaris were mixed and crushed, mixed with deionized water, sterilized, inoculated with Lactobacillus plantarum, cultured, and the supernatant was concentrated and freeze-dried to obtain a fermentation extract; (12) adding calcium chloride to the acetic acid solution, stirring well, then adding chitosan, stirring well, to obtain a calcium chloride-chitosan acetic acid mixed solution; preparing a sodium alginate solution, adding the fermentation extract, stirring well, adding the solution to the calcium chloride-chitosan acetic acid mixed solution, filtering, washing, and obtaining a soil improvement material; (2) Preparation of water-retaining materials: (21) Sodium hydroxide solution was added to 3-aminophenylboronic acid and mixed, acryloyl chloride was added, reacted, pH was adjusted, filtered, and purified by precipitation to obtain acrylamidephenylboronic acid; (22) crushing the straw, heating it, cooling it, mixing it with a KOH solution, drying it, heating it, cooling it, washing it, drying it, and grinding it to obtain straw charcoal powder; (23) The straw charcoal powder was added to a 10 mol / L nitric acid solution, ultrasonicated, stirred, filtered, washed, dried, mixed with NMP, and ultrasonically added dropwise with a 1 mol / L HNO3 solution and VTES, ultrasonicated, stirred, cooled, filtered, washed, and dried to obtain a modified straw charcoal material; (24) Acrylamide phenylboronic acid, modified straw charcoal material, DMAPAA, and AM were added to DMSO and mixed evenly, and AIBN was added, reacted, cooled, filtered, washed, and freeze-dried; (25) Na2CO3 solution and NaHCO3 solution are mixed to obtain a buffer solution, sodium alginate is added to the buffer solution and mixed to obtain a mixed solution A, the freeze-dried product obtained in step (24) is mixed with the buffer solution to obtain a mixed solution B, the mixed solution A is added to the mixed solution B, the mixture is reacted, and dried to obtain a water-retaining material; (3) Planting of seedlings and afforestation; (4) Routine management after seedlings are planted.

2. The drought soil water conservation and afforestation method according to claim 1, characterized in that: In step (12), in the calcium chloride-chitosan acetic acid mixed solution, the mass volume fraction of calcium chloride is 4% w / v, the mass volume fraction of chitosan is 0.3% w / v; the mass ratio of calcium chloride to sodium alginate is 2:1; and the mass ratio of fermentation extract to sodium alginate is 1:2-3.

3. The drought soil water conservation and afforestation method according to claim 2, characterized in that: In step (21), the sodium hydroxide solution, 3-aminophenylboronic acid and acryloyl chloride are used in a ratio of 20 mL:10 mmol:20 mmol.

4. The drought soil water conservation and afforestation method according to claim 3, characterized in that: In step (23), the ratio of the straw charcoal powder to the 10 mol / L nitric acid solution is 1 g:10-15 mL; the ratio of the straw charcoal powder to NMP is 1 g:25-30 mL; and the volume ratio of NMP, 1 mol / L HNO3 solution, and VTES is 50-60:1:5-6.

5. The drought soil water conservation and afforestation method according to claim 4, characterized in that: In step (24), the mass ratio of acrylamide phenylboronic acid, modified straw charcoal material, DMAPAA, and AM is 2-3:8-12:2-3:5-7; the amount ratio of modified straw charcoal material to DMSO is 1 g:100 mL; and the amount of AIBN is 1-1.5 wt% of acrylamide.

6. The drought soil water conservation and afforestation method according to claim 5, characterized in that: In step (25), in the mixed solution A, the mass concentration of sodium alginate in the buffer solution is 20-30 mg / mL; in the mixed solution B, the mass concentration of the freeze-dried product in the buffer solution is 0.1 g / mL; and the mass ratio of sodium alginate to the freeze-dried product is 1:10-15.

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