A method for reforesting sandy land

Abstract

The present invention provides a method for regreening sandy land, comprising the following steps: forming holes on the surface of the sandy land, burying stick fertilizer in the holes, forming a stick fertilizer layer containing the stick fertilizer, and a surface sandy soil layer located above the stick fertilizer layer; applying sludge material on the surface of the surface sandy soil layer, and mixing the sludge material with at least part of the surface sandy soil layer to form a mixed nutrient layer; wherein the sludge material includes dried sludge, fulvic acid, nitrogen fertilizer, nitrification inhibitor and water retaining agent; applying nitrogen-fixing material on the surface of the mixed nutrient layer to form a nitrogen-fixing layer; wherein the nitrogen-fixing material includes a carrier, and cyanobacteria and nitrogen-fixing bacteria loaded on the carrier; after applying a sowing material containing moss skin on the surface of the nitrogen-fixing layer, pioneer plants are planted on the sandy land. The present invention can take into account improving the water retention capacity of sandy land, maintaining its nutrients and fertility, improving the growth environment of microorganisms and vegetation in sandy land, improving the benign material cycle of sandy land, and increasing the duration of sandy land restoration effect.

Description

Technical Field

[0001] The invention relates to the field of environmental engineering, and in particular to a method for reforesting sandy land. Background Art

[0002] Sandy land usually has good water permeability and air permeability, but it is also accompanied by problems such as poor water retention, rapid nutrient loss and low fertility, and vegetation growth is poor. Management and greening of sandy land are of great significance to improving ecology and increasing land productivity. An important reason for the above problems in sandy land is the lack of soil organic matter. Organic matter can increase the cohesion and stability of the soil. When the soil lacks organic matter, the cohesion between soil particles will weaken, causing the soil to become loose and the water and fertility in the soil to be lost rapidly. At the same time, the organic matter in the soil is closely related to the biological activity of the soil. Organic matter is the main food source for soil microorganisms. The lack of organic matter will lead to a decrease in the number of microorganisms, thereby reducing the circulation and conversion capacity of nutrients in the soil, forming a vicious circle. Increasing the organic matter in sandy land is an effective means to fundamentally improve the soil structure and enhance soil fertility.

[0003] Establishing a stable vegetation system is also an effective way to improve soil structure. The roots of shrubs and herbaceous plants can fix the soil, effectively prevent wind and water erosion, and maintain soil stability and fertility. This is a traditional way of governance. Specific methods include sand control and afforestation, closing mountains for afforestation, and closed-off protection. However, these methods have many restrictions, such as high economic costs, large labor requirements, and long time consumption, making it difficult to achieve large-scale promotion and application in the short term.

[0004] In the 1980s, biologists realized the important role of artificial algae crusts in water conservation, sand fixation, and improvement of biochemical properties of desertified soil. Artificial algae crusts are mainly achieved by adding artificial algae species to the surface of sand. After a series of physiological and biochemical reactions, the algae species grow and reproduce on the surface, and use algae filaments and secreted extracellular polymers to aggregate soil particles together to form a tight crust of algae-soil particles-algae bodies, so as to achieve the purpose of sand fixation and soil improvement. In addition, the organic acids secreted by algae during their growth and the waste produced by growth metabolism can also regulate soil acidity and alkalinity and improve soil conditions. However, using artificial algae crusts alone to repair sandy land often takes a long time and the effect is difficult to guarantee.

[0005] Increasing soil organic matter, establishing vegetation systems, and adding artificial algae crusts are effective ways to improve sandy land, but these restoration methods are often ineffective and difficult to maintain. There are also common problems such as difficulty in maintaining fertility effectiveness after adding organic matter and fertilizers to sandy land, and difficulty in achieving a virtuous cycle between sandy land restoration and plant growth.

[0006] Therefore, how to overcome the problems of poor water retention capacity of sandy soil, rapid nutrient loss and low fertility, maintain the effectiveness of fertility, and improve the growth environment of microorganisms and vegetation in sandy soil, improve the benign material cycle of sandy soil, and increase the duration of sandy soil restoration effects are technical problems that need to be urgently solved in this field. Summary of the invention

[0007] The present invention provides a method for reforesting sandy land, which can improve the water retention capacity of sandy land, maintain its nutrients and fertility, improve the growth environment of sandy land microorganisms and vegetation, improve the benign material cycle of sandy land, and increase the duration of sandy land restoration effect.

[0008] According to one aspect of the present invention, there is provided a method for regreening sandy soil, comprising the following steps: forming holes on the surface of the sandy soil, burying stick fertilizer in the holes to form a stick fertilizer layer containing the stick fertilizer, and a surface sand layer located above the stick fertilizer layer; applying sludge material on the surface of the surface sand layer, and mixing the sludge material with at least a portion of the surface sand layer to form a mixed nutrient layer; wherein the sludge material comprises dried sludge, fulvic acid, nitrogen fertilizer, nitrification inhibitor and water retaining agent; applying nitrogen-fixing material on the surface of the mixed nutrient layer to form a nitrogen-fixing layer; wherein the nitrogen-fixing material comprises a carrier, and cyanobacteria and nitrogen-fixing bacteria carried on the carrier; after applying a spreading material containing moss skin on the surface of the nitrogen-fixing layer, pioneer plants are planted on the sandy soil.

[0009] According to one embodiment of the present invention, the hole has a diameter of 8-10 cm and a depth of 80-100 cm; and / or, the diameter of the fertilizer stick is 6-8 cm and the length is 60-80 cm; and / or, a plurality of holes are formed on the surface of the sandy soil, and one fertilizer stick is buried in each hole; and / or, the density of the holes formed on the surface of the sandy soil is 3-9 holes / m 2 ; and / or, the process of burying the fertilizer sticks in the hole includes: placing the fertilizer sticks in the hole, watering to moisten the surface of the fertilizer sticks and then filling with soil, and forming a surface sand layer above the fertilizer stick layer by the filling with soil.

[0010] According to one embodiment of the present invention, the preparation process of the fertilizer stick includes: mixing organic nutrient soil and compound fertilizer to obtain a first mixture; controlling the moisture content of the first mixture to 45-52%, and then adding a binder thereto to obtain a second mixture; pressing the second mixture into a molded product; drying the molded product to a moisture content of 35%~40% to obtain the fertilizer stick.

[0011] According to one embodiment of the present invention, the mass ratio of the organic nutrient soil to the compound fertilizer is (2-5):1; and / or, the compound fertilizer includes nitrogen-phosphorus-potassium compound fertilizer, in which the mass percentage of nitrogen element is greater than or equal to 15%, the mass percentage of phosphorus element is greater than or equal to 15%, and the mass percentage of potassium element is greater than or equal to 15%; and / or, the mass percentage of the adhesive in the second mixture is 2%-3%; and / or, the adhesive includes water-soluble starch and / or sodium alginate; and / or, the The process of adding the binder includes: mixing the binder with water at a temperature of 40-50°C to obtain a mixed liquid; adding the mixed liquid to the first mixture; wherein the mass ratio of the binder to water is 1:(5-10); and / or, the pressing pressure of the pressing molding is 7-12MPa; and / or, the pressing molding process includes: gradually pressurizing the second mixture at a pressure increase rate of 1-2MPa / s until it is pressurized to the pressing pressure, and maintaining the pressing pressure for 3-5s to press the second mixture into a mold.

[0012] According to one embodiment of the present invention, in the sludge material, the mass percentage of the dried sludge is 85-95%, the mass percentage of the fulvic acid is 2-3%, the mass percentage of the nitrogen fertilizer is 1-2%, the mass percentage of the nitrification inhibitor is 0.2-0.5%, and the mass percentage of the water retaining agent is 1-1.5%; and / or, the water content of the dried sludge is 40-60%; and / or, the particle size of the dried sludge is less than or equal to 0.5 cm; and / or, the application amount of the sludge material is 2-3 kg / m 2 ; and / or, mixing the sludge material with at least a portion of the surface sand layer means mixing the sludge material with a 10 cm thick sand layer above the surface sand layer to form the mixed nutrient layer.

[0013] According to one embodiment of the present invention, the carrier in the nitrogen-fixing material comprises a semi-carbonized corn cob, and the preparation process of the semi-carbonized corn cob comprises: crushing the corn cob into corn cob particles with a particle size of 0.2-0.5 cm; carbonizing the corn cob particles at 190-220° C. for 30-60 min to obtain the semi-carbonized corn cob; and / or, the preparation process of the nitrogen-fixing material comprises: soaking the carrier in an impregnation solution containing cyanobacteria for 2-5 hours to obtain a carrier loaded with cyanobacteria; spraying a bacterial solution containing nitrogen-fixing bacteria on the carrier loaded with cyanobacteria to load nitrogen-fixing bacteria on the carrier loaded with cyanobacteria to obtain the nitrogen-fixing material; and / or, the nitrogen-fixing bacteria comprises autotrophic nitrogen-fixing bacteria and / or symbiotic nitrogen-fixing bacteria; and / or, the application amount of the nitrogen-fixing material is 0.5-3 kg / m 2 .

[0014] According to one embodiment of the present invention, the particle size of the spreading material containing moss skin is less than or equal to 2 cm; and / or, the spreading material containing moss skin contains auxin; and / or, the application amount of the spreading material containing moss skin is 1-2 kg / m 2 .

[0015] According to one embodiment of the present invention, after applying a spreading material containing moss skin on the surface of the nitrogen-fixing layer, water is applied to moisten the soil, and the water moistens the soil with a surface thickness of at least 10 cm. After 10-20 days, the pioneer plants are planted on the sandy land; wherein, during the 10-20 days, the sandy land is watered intermittently.

[0016] According to one embodiment of the present invention, the pioneer plants include herbaceous plants and / or legumes, the herbaceous plants include Cynodon dactylon and / or Lolium, and the legumes include Junggar leafless bean and / or Oxytropis glabra.

[0017] According to one embodiment of the present invention, the planting density of the pioneer plants is 40-70 g / m 2 .

[0018] The implementation of the present invention has at least the following beneficial effects:

[0019] (1) In order to solve the problems of poor water retention capacity, rapid nutrient loss and low fertility of sandy soil, the present invention proposes an "underground-ground" combined fertilization method. Organic-inorganic stick fertilizer is deeply applied underground, and organic matter and chemical fertilizer are slowly released to continuously improve the deep soil and reduce fertility loss; dried sludge and water retaining agent are applied above ground, and their water absorption and water retention capacity are used to help sandy soil lock surface moisture. At the same time, the rich nitrogen, phosphorus, potassium and organic matter in the sludge can quickly improve the soil structure and nutritional status of the surface land.

[0020] (2) In order to solve the problem that the growth environment of microorganisms and vegetation in sandy soil is poor and unfavorable for material circulation, the present invention proposes a biological promotion scheme, using semi-carbonized corn cobs as carriers to load nitrogen-fixing bacteria to enhance the nitrogen fixation capacity of the soil; adding humic acid and nitrogen fertilizer to promote plant rooting; adding nitrification inhibitors to inhibit the conversion of ammonia nitrogen in sludge and fertilizers into nitrate nitrogen, regulating the release period and rate of nitrogen nutrients, and promoting efficient absorption by plants.

[0021] (3) In view of the problem that the restoration effect of sandy land is difficult to sustain and form a virtuous cycle, the present invention proposes to construct a "soil-bacteria-algae-moss-plant" microecological system. Use sludge to improve the soil and provide the original nutrition and power for the establishment of the microecological system; use bacteria to improve the carbon and nitrogen material cycle; use the metabolites of terrestrial cyanobacteria to slowly improve the soil structure and start the recovery of soil activity. The cyanobacteria and nitrogen-fixing bacteria coexist and cooperate at the same time; inoculate moss skin to accelerate the formation of soil crust in sandy land through human intervention, form an "algae-moss" system with cyanobacteria, and increase stability; plant pioneer plants-leguminous plants to provide surface plants that coexist with nitrogen-fixing bacteria, promote carbon and nitrogen cycles, and at the same time, the root growth process will wrap the deeper sand particles to form aggregates and enhance water retention.

[0022] Therefore, the present invention can improve the water retention capacity of sandy land, maintain its nutrients and fertility, improve the growth environment of sandy land microorganisms and vegetation, improve the benign material cycle of sandy land, and increase the duration of sandy land restoration effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of constructing a "soil + bacteria + algae + moss + plants" microecological system for restoring desertified land. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention provides a method for reforesting sandy land, see Figure 1 The method comprises the following steps: forming holes on the surface of sandy soil, burying stick fertilizer in the holes to form a stick fertilizer layer containing the stick fertilizer, and a surface sand layer located above the stick fertilizer layer; applying sludge material on the surface of the surface sand layer, and mixing the sludge material with at least part of the surface sand layer to form a mixed nutrient layer (a mixed layer of dried sludge and sand); wherein the sludge material comprises dried sludge, fulvic acid, nitrogen fertilizer, nitrification inhibitor and water retaining agent; applying nitrogen-fixing material on the surface of the mixed nutrient layer to form a nitrogen-fixing layer; wherein the nitrogen-fixing material comprises a carrier, and cyanobacteria and nitrogen-fixing bacteria carried on the carrier; after applying a spreading material containing moss skin on the surface of the nitrogen-fixing layer, pioneer plants are planted on the sandy soil.

[0026] In this way, stick fertilizer is deeply applied underground, and the organic matter and chemical fertilizer in the stick fertilizer are slowly released, which continuously improves the deep soil and reduces the loss of fertility; dried sludge and water retaining agent are applied on the ground, and the water absorption and water retention capacity of the two helps the sandy land lock the surface water. At the same time, the rich nitrogen, phosphorus, potassium and organic matter in the sludge can quickly improve the soil structure and nutritional status of the surface land. This improves the poor water retention capacity, rapid nutrient loss and low fertility of the sandy land.

[0027] In addition, the carrier-loaded nitrogen-fixing bacteria can enhance the nitrogen-fixing capacity of the soil; the addition of fulvic acid and nitrogen fertilizer can promote plant rooting; the addition of nitrification inhibitors can inhibit the conversion of ammonia nitrogen in sludge and fertilizer to nitrate nitrogen, regulate the release period and rate of nitrogen nutrients, and promote efficient absorption by plants. This improves the poor growth environment of sandy soil microorganisms and vegetation, which is not conducive to material circulation.

[0028] In addition, the present invention constructs a "soil-bacteria-algae-moss-plant" microecological system (including a bacteria-algae-moss symbiotic system), using sludge to improve soil and provide the original nutrition and power for the establishment of the microecological system; using bacteria to improve the carbon and nitrogen material cycle; using terrestrial cyanobacteria metabolites to slowly improve soil structure and start the recovery of soil activity, while cyanobacteria and nitrogen-fixing bacteria coexist and cooperate; using moss skin inoculation to accelerate the formation of soil crust in sandy land through human intervention, forming an "algae-moss" system with cyanobacteria to increase stability; planting pioneer plants-leguminous plants to provide surface plants that coexist with nitrogen-fixing bacteria, promoting carbon and nitrogen cycles, and at the same time, the root growth process wraps deeper sand particles to form aggregates and enhance water retention. This improves the situation where the sandy land restoration effect is difficult to sustain and difficult to form a virtuous cycle.

[0029] In some embodiments, the pore size of the hole can be 8-10cm, for example 8cm, 8.5cm, 9cm, 9.5cm, 10cm or a range consisting of any two thereof, and the depth can be 80-100cm, for example 80cm, 85cm, 90cm, 95cm, 100cm or a range consisting of any two thereof.

[0030] Specifically, a soil boring machine may be used to drill holes in the sandy soil surface.

[0031] In addition, the diameter of the fertilizer stick can be 6-8cm, for example 6cm, 6.5cm, 7cm, 7.5cm, 8cm or a range consisting of any two thereof, and the length is 60-80cm, for example 60cm, 65cm, 70cm, 75cm, 80cm or a range consisting of any two thereof.

[0032] In addition, multiple holes can be formed on the surface of the sandy soil, and a fertilizer stick can be buried in each hole.

[0033] In addition, the density of holes formed on the surface of sandy soil can be 3~9 / m 2 , for example 3 pieces / m 2 , 4 pieces / m 2 , 5 pieces / m 2 , 6 pieces / m 2 , 7 pieces / m 2 , 8 pieces / m 2 , 9 pieces / m 2 Or a range consisting of any two of them.

[0034] Preferably, the punching positions may be at the four corners and the center point of each square meter of land.

[0035] In addition, the process of burying the fertilizer sticks in the holes may include: placing the fertilizer sticks in the holes, watering to moisten the surface of the fertilizer sticks, and then filling with soil, so as to form a surface sand layer located above the fertilizer stick layer by filling with soil.

[0036] Specifically, the above-mentioned fertilizer sticks can be organic-inorganic fertilizer sticks.

[0037] In some embodiments, the preparation process of fertilizer sticks may include: mixing organic nutrient soil and compound fertilizer to obtain a first mixture; controlling the moisture content of the first mixture to 45-52%, for example, 45%, 47%, 49%, 51%, 52% or a range consisting of any two thereof, and then adding a binder thereto to obtain a second mixture; pressing the second mixture into shape to obtain a molded product; drying the molded product to a moisture content of 35%~40%, for example, 35%, 36%, 37%, 38%, 39%, 40% or a range consisting of any two thereof, so as to prevent it from breaking during transportation, and finally obtaining fertilizer sticks.

[0038] Specifically, after the second mixture is mixed evenly, it can be pressed into a rod-making machine.

[0039] Specifically, the organic nutrient soil may include aerobic fermentation products of one or more of sludge, livestock and poultry manure and garden waste, mushroom residue, and straw. The embodiments of the present invention can aerobic ferment these materials by conventional methods in the art to obtain corresponding aerobic fermentation products, without particular limitation.

[0040] Specifically, the organic nutrient soil may be a component of the aerobic fermentation product sieved through a sieve with a pore size of 0.4-0.6 cm.

[0041] In specific implementation, the moisture content of the first mixture can be controlled by adding water or air drying.

[0042] In some embodiments, the mass ratio of the organic nutrient soil to the compound fertilizer may be (2-5):1, such as 2:1, 3:1, 4:1, 5:1 or a range consisting of any two thereof.

[0043] In addition, the compound fertilizer includes nitrogen-phosphorus-potassium compound fertilizer, in which the mass percentage of nitrogen element can be greater than or equal to 15%, the mass percentage of phosphorus element can be greater than or equal to 15%, and the mass percentage of potassium element can be greater than or equal to 15%.

[0044] In addition, the mass percentage of the binder in the second mixture may be 2%-3%, for example, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3% or a range consisting of any two thereof.

[0045] Additionally, the binder may include water-soluble starch and / or sodium alginate.

[0046] In addition, the process of adding the adhesive thereto may include: mixing the adhesive with water at a temperature of 40-50° C. to obtain a mixed liquid; and adding the mixed liquid to the first mixture; wherein the mass ratio of the adhesive to water is 1:(5-10).

[0047] Specifically, the temperature of water mixed with the adhesive can be 40°C, 42°C, 44°C, 46°C, 48°C, 50°C or a range consisting of any two thereof; the mass ratio of adhesive to water can be 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or a range consisting of any two thereof.

[0048] In addition, the pressing pressure of the press molding can be 7-12 MPa, for example, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa or a range consisting of any two thereof.

[0049] In addition, the compression molding process may include: gradually pressurizing the second mixture at a pressure increase rate of 1-2 MPa / s until it reaches the compression pressure, and maintaining the compression pressure for 3-5 seconds (i.e., starting to reduce the pressure after staying at the compression pressure for 3-5 seconds) to compress the second mixture into shape.

[0050] Specifically, the pressure increase rate for gradually pressurizing the second mixture may be 1 MPa / s, 1.2 MPa / s, 1.4 MPa / s, 1.6 MPa / s, 1.8 MPa / s, 2 MPa / s, or a range consisting of any two thereof.

[0051] In this way, nutrients can be provided to the sandy soil with a thickness of about 1m above the sandy soil, and the nutrition of the deep soil can be increased. At the same time, the large amount of organic matter contained in the sludge can be used to slowly improve the water and fertilizer retention performance of the sandy soil and improve the soil structure. Compared with applying fertilizer first and then mixing and drilling fertilizer, the advantages of using the above-mentioned stick fertilizer vertical application are that the workload is small, the fertilization depth is deeper, and the fertilizer effect is slow-released and long-term effective.

[0052] In some embodiments, the mass percentage of the dried sludge can be 85-95%, for example, 85%, 87%, 89%, 91%, 93%, 95% or a range consisting of any two thereof; the mass percentage of fulvic acid can be 2-3%, for example, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3% or a range consisting of any two thereof; the mass percentage of nitrogen fertilizer can be 1-2%, for example, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2% or a range consisting of any two thereof; the mass percentage of nitrification inhibitor can be 0.2-0.5%, for example, 0.2%, 0.3%, 0.4%, 0.5% or a range consisting of any two thereof; the mass percentage of water retaining agent can be 1-1.5%, for example, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5% or a range consisting of any two thereof.

[0053] In addition, the moisture content of the dried sludge may be 40-60%, for example, 40%, 45%, 50%, 55%, 60% or a range consisting of any two thereof.

[0054] In addition, the particle size of the dried sludge can be less than or equal to 0.5 cm.

[0055] In addition, the application rate of sludge material can be 2-3kg / m 2 , for example 2kg / m 2 , 2.2kg / m 2 , 2.4kg / m 2 , 2.6kg / m 2 , 2.8kg / m 2 , 3kg / m 2 Or a range consisting of any two of them.

[0056] Specifically, the amount of sludge applied refers to the mass of sludge spread on the surface sand layer per square meter, that is, the mass of sludge on the surface of the surface sand layer per square meter is 2-3kg / m 2 .

[0057] Specifically, the various components in the sludge material should be mixed evenly before application.

[0058] Furthermore, mixing the sludge material with at least a part of the surface sandy soil layer means mixing the sludge material with a sandy soil region with a thickness of 10 cm of the surface sandy soil layer to form a mixed nutrient layer.

[0059] In this way, the fertility of the surface sandy soil and its water and fertilizer retention performance can be quickly improved, and at the same time, a growth environment is provided for the tiny plants at the soil interface. Sludge contains a large amount of organic matter and nitrogen, phosphorus and potassium. Dry sludge is used instead of aerobic fermentation and decomposed sludge because dry sludge has a strong ability to absorb and retain water, which can help lock water on the surface of the sand. The role of fulvic acid and nitrogen fertilizer is to promote plant rooting. At the same time, fulvic acid can increase the humus of sandy soil. The role of nitrification inhibitor is to inhibit the conversion of ammonia nitrogen in sludge and fertilizer to nitrate nitrogen, regulate the release period and rate of nitrogen nutrients, and thus promote efficient absorption by plants. Water retaining agent can further enhance water retention capacity.

[0060] In some embodiments, the carrier in the nitrogen-fixing material may include semi-carbonized corn cobs, which can provide fixation sites for cyanobacteria and nitrogen-fixing bacteria and enable them to maintain a certain moisture content for a long time to maintain high activity. The preparation process of the semi-carbonized corn cobs may include: crushing the corn cobs into corn cob particles with a particle size of 0.2-0.5 cm; carbonizing the corn cob particles at 190-220° C. for 30-60 minutes to obtain semi-carbonized corn cobs.

[0061] Specifically, the particle size of the corn cob particles can be 0.2 cm, 0.3 cm, 0.4 cm, 0.5 cm or a range consisting of any two of them. The corn cob particles can be carbonized in a carbonization furnace. The carbonization temperature can be 190°C, 200°C, 210°C, 220°C or a range consisting of any two of them. The carbonization time can be 30 min, 40 min, 50 min, 60 min or a range consisting of any two of them.

[0062] In addition, the preparation process of the nitrogen-fixing material may include: soaking the carrier in an impregnation solution containing cyanobacteria for 2-5 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours or a range consisting of any two of them, to obtain a carrier loaded with cyanobacteria; spraying a bacterial solution containing nitrogen-fixing bacteria on the carrier loaded with cyanobacteria to load the nitrogen-fixing bacteria on the carrier loaded with cyanobacteria to obtain the nitrogen-fixing material.

[0063] In the specific implementation, the semi-carbonized corn cob is soaked in a cyanobacteria liquid (an immersion liquid containing cyanobacteria) for 2-5 hours, so that the cyanobacteria can fully attach and grow on the surface and internal pores of the semi-carbonized corn cob. After soaking, the semi-carbonized corn cob loaded with cyanobacteria is taken out from the cyanobacteria liquid, and a bacterial liquid containing nitrogen-fixing bacteria is sprayed on it to obtain a nitrogen-fixing material.

[0064] In specific implementation, cyanobacteria can be selected from local biological crust samples in sandy land, and the cyanobacteria are separated, purified, and then cultured to obtain nitrogen-fixing cyanobacteria, and the nitrogen-fixing cyanobacteria are expanded and cultured to obtain cyanobacterial liquid (i.e., an immersion liquid containing cyanobacteria). The specific method includes: collecting natural biological crusts from land with good plant growth near sandy land, weighing a certain mass of biological crusts, stirring them evenly, and then culturing them in a constant temperature and light incubator with BG-11 culture medium, maintaining the temperature at 27±1°C, the light-dark ratio of 16h:8h, separating and purifying 8-10 times to obtain local cyanobacteria varieties, and further expanding and culturing to obtain cyanobacterial liquid.

[0065] Among them, biological crusts are also called biological soil crusts, soil microbial crusts, etc., which are complexes formed by the bonding of cryptophytes such as microbacteria, fungi, algae, lichens, mosses, and their hyphae, secretions, etc. with soil gravel. It is an important type of surface cover in arid and semi-arid areas. The existence of biological crusts is of great significance to the fixation of deserts, the physical, chemical and biological properties of the soil surface, and the resistance of soil to wind and water erosion, and plays an important role in promoting the evolution of desert vegetation. In the embodiment of the present invention, the use of the above-mentioned cyanobacteria is conducive to adapting to materials such as the fertilizer layer, the mixed nutrient layer, the nitrogen-fixing layer, the spreading material containing moss skin, and the pioneer plants planted on the sandy land, taking into account the improvement of the water retention capacity of the sandy land, maintaining its nutrients and fertility, improving the growth environment of microorganisms and vegetation in the sandy land, improving the benign material cycle of the sandy land, and increasing the duration of the sandy land restoration effect.

[0066] Furthermore, the nitrogen-fixing bacteria may include autotrophic nitrogen-fixing bacteria and / or symbiotic nitrogen-fixing bacteria.

[0067] Specifically, the bacterial solution containing nitrogen-fixing bacteria can be prepared by dissolving a nitrogen-fixing bacteria agent in a nutrient solution. The nitrogen-fixing bacteria can form a synergistic relationship with cyanobacteria and plants to construct a microecological nitrogen cycle.

[0068] In addition, the application rate of nitrogen-fixing materials can be 0.5-3kg / m 2 , for example 0.5kg / m 2 , 1kg / m 2 , 1.5kg / m 2 , 2kg / m 2 , 2.5kg / m 2 , 3kg / m 2 Or a range consisting of any two of them.

[0069] Specifically, the application rate of nitrogen-fixing materials refers to the mass of nitrogen-fixing materials spread on the mixed nutrient layer per square meter, that is, the mass of nitrogen-fixing materials on the surface of the mixed nutrient layer per square meter is 0.5-3kg / m 2 .

[0070] In this way, the semi-carbonized corncobs provide a fixation site for cyanobacteria and nitrogen-fixing bacteria, allowing them to maintain a certain amount of moisture for a long time and maintain high activity. After the cyanobacteria are added to the surface of the mixed nutrient layer, they can secrete extracellular polysaccharides to bind the sand particles, while the algal filaments further assist in binding the sand particles, and the organic matter produced by algae metabolism slowly improves the soil structure. Cyanobacteria and nitrogen-fixing bacteria can coexist, and cyanobacteria and nitrogen-fixing bacteria can form a symbiotic relationship with plants in different ways, thereby achieving biological nitrogen fixation and providing the necessary nitrogen nutrition for the growth and development of plants.

[0071] In some embodiments, the particle size (diameter) of the broadcast material containing moss bark may be less than or equal to 2 cm.

[0072] In addition, spreading material containing moss bark can contain auxins.

[0073] In addition, the application rate of the spreading material containing moss skin can be 1-2 kg / m 2 , for example 1kg / m 2 , 1.2kg / m 2 , 1.4kg / m 2 , 1.6kg / m 2 , 1.8kg / m 2 , 2kg / m 2 Or a range consisting of any two of them.

[0074] Specifically, the application amount of the spreading material containing moss skin refers to the mass of the spreading material containing moss skin spread on the nitrogen-fixing layer per square meter, that is, the mass of the spreading material containing moss skin on the surface of the nitrogen-fixing layer per square meter is 1-2 kg / m 2 .

[0075] In the specific implementation, the moss skin can be taken from the nearby forest or rock surface, crushed into pieces with a particle size less than or equal to 2 cm, and the moss skin is drenched with water dissolved with auxin to make a spreading material containing moss skin. The spreading material containing moss skin is spread on the surface of the nitrogen-fixing layer at a spreading rate of 1-2 kg / m 2 . After spreading, water the soil sufficiently to at least wet the top 10 cm of soil, and at the same time, allow the dried sludge and water retaining agent to fully absorb water, and maintain a certain amount of moisture in the surface sand so that cyanobacteria and moss skin can grow. If there is no natural rainfall, water the soil artificially every 5-8 days, such as 5 days, 6 days, 7 days, 8 days or any two of them, for 30-50 days, such as 30 days, 35 days, 40 days, 45 days, 50 days or any two of them, so that cyanobacteria and moss skin can be fully colonized on carriers such as semi-carbonized corn cobs. In this way, the formation of soil crust in sandy land can be accelerated by artificial inoculation of moss.

[0076] In some embodiments, after applying a broadcast material containing moss bark on the surface of the nitrogen-fixing layer, water is applied to moisten the soil, and the surface thickness of the soil is at least 10 cm. After 10-20 days, for example, 10 days, 12 days, 14 days, 16 days, 18 days, 20 days or a range composed of any two of them, pioneer plants are planted on the sandy land; wherein the sandy land is intermittently watered within 10-20 days.

[0077] Specifically, pioneer plants can be planted by sowing grass seeds. The pioneer plant seeds should be mixed evenly and fully soaked in water with added auxin before sowing to allow the seeds to absorb water fully, which is conducive to the seeds taking root quickly after being sown on the surface of the sandy soil layer.

[0078] In some embodiments, the pioneer plants may include herbs and / or legumes, the herbs may include Bermuda grass and / or Lolium, and the legumes may include Glechoma longituba and / or Oxytropis glabra.

[0079] Specifically, when planting pioneer plants, a mixed sowing method of various types of plants can be adopted.

[0080] Specifically, among the herbaceous plants, Bermuda grass and ryegrass grow fast and have strong environmental tolerance. They can take root quickly under conditions of sufficient nutrition and water. During the growth process of their root system, they wrap the sand particles around the roots to form aggregates and enhance water retention. Nitrogen-fixing bacteria and legumes can coexist well, and the rhizobia can induce plants to form nodules. Legumes preferably include species such as Junggar leafless bean and Oxytropis fasciata, which are excellent pioneer sand-fixing plants.

[0081] In some embodiments, the planting density of pioneer plants can be 40-70 g / m 2 , for example 40g / m 2 , 50g / m 2 , 60g / m 2 , 70g / m 2 Or a range consisting of any two of them, so that the seeds are not easily sown too sparsely or too densely.

[0082] In this way, planting pioneer plants provides surface plants that can coexist with cyanobacteria and nitrogen-fixing bacteria, providing a symbiotic site for cyanobacteria and nitrogen-fixing bacteria, which can promote nitrogen and carbon cycles and form a virtuous cycle. The initial addition of nitrogen fertilizer and sludge can provide initial nutrition guarantee for plant growth, enabling rapid growth. After the plants grow, they can gradually produce nitrogen and organic matter by relying on the microecological cycle of the surface soil, slowly improving the soil ecology and gradually getting rid of human intervention.

[0083] In specific implementation, the above-mentioned sandy land restoration method may include the following steps:

[0084] S1. Vertical application of organic and inorganic fertilizer sticks in sandy land to improve deep soil and enhance fertility

[0085] (1) Preparation of stick fertilizer

[0086] The organic nutrient soil and compound fertilizer are mixed in a mass ratio of (2-5):1 to obtain a first mixture, and the moisture content of the first mixture is controlled to be 45-52% by adding water or air drying; a binder is added thereto and mixed evenly to obtain a second mixture, wherein the binder accounts for 2-3% of the total mass of the second mixture; the second mixture is then pressed into shape by a rod making machine at a pressing pressure of 7-12 MPa; after pressing and molding, the pressed product is lightly dried to a moisture content of 35-40% to obtain a rod fertilizer.

[0087] Among them, organic nutrient soil is the aerobic fermentation product of sludge, livestock and poultry manure, garden waste, mushroom residue, and straw after screening through a sieve with an aperture of 0.4-0.6cm. The compound fertilizer is a nitrogen-phosphorus-potassium compound fertilizer, in which the content of nitrogen, phosphorus, and potassium is not less than 15%. The adhesive is water-soluble starch or sodium alginate, which should be dissolved in 40-50℃ warm water before use.

[0088] In addition, the pressing process adopts a gradual pressurization method with a pressure increase rate of 1-2MPa / S.

[0089] (2) Method of applying stick fertilizer (forming a stick fertilizer layer and a surface sand layer above the stick fertilizer layer)

[0090] First, use a soil drill to drill holes on the sandy soil surface with a diameter of 8-10cm and a depth of 80-100cm. Put a stick fertilizer in each hole, water the surface of the fertilizer stick and fill it with soil to form a fertilizer stick layer and a surface sand layer above the fertilizer stick layer. Five holes are drilled per square meter of soil, at the four corners and the center; the size of the fertilizer stick is 6-8cm in diameter and 60-80cm in length.

[0091] S2. Application of “dried sludge + fulvic acid + nitrogen fertilizer + nitrification inhibitor + water retaining agent” to improve the surface soil (form a mixed nutrient layer)

[0092] The dried sludge, fulvic acid, nitrogen fertilizer, nitrification inhibitor and water retaining agent are mixed evenly according to the mass percentage of 85-95%, 2-3%, 1-2%, 0.2-0.5% and 1-1.5% respectively to obtain the sludge material. The moisture content of the dried sludge is 40-60%, and it needs to be crushed to a particle size of no more than 0.5cm; the mass of the sludge material spread on the surface sand layer per square meter is 2-3kg / m 2 After application, lightly mix it with the surface 10cm thick sand to form a mixed nutrient layer.

[0093] S3. Treatment and application of semi-carbonized corncobs as carriers for cyanobacteria and nitrogen-fixing bacteria

[0094] The corn cob is crushed into particles with a particle size of 0.2-0.5 cm, and then placed in a carbonization furnace for carbonization at 190-220°C for 30-60 minutes to obtain a semi-carbonized corn cob. The cyanobacteria selected from the local biological crust sample are separated and purified and then cultured to obtain nitrogen-fixing cyanobacteria, and the nitrogen-fixing cyanobacteria are expanded and cultured to obtain cyanobacterial liquid. The specific method includes: collecting natural biological soil crusts from land with good plant growth near sandy land, weighing a certain mass of the collected biological soil crusts, stirring them evenly, and then using BG-11 culture medium to statically culture in a constant temperature and light incubator, maintaining the temperature at 27±1°C and the light-dark ratio at 16h:8h during the culture process, separating and purifying the biological soil crust obtained after static culture for 8-10 times to obtain local cyanobacteria varieties, and further expanding and culturing them to obtain cyanobacterial liquid. The semi-carbonized corn cob is soaked in the cyanobacterial liquid for 2-5 hours to allow the cyanobacteria to fully attach and grow on the surface and internal pores of the semi-carbonized corn cob. After soaking, the semi-carbonized corn cobs loaded with cyanobacteria are removed from the cyanobacteria liquid, and the bacterial liquid containing nitrogen-fixing bacteria is sprayed on them. The bacterial liquid and the semi-carbonized corn cobs loaded with cyanobacteria are fully mixed and applied to the mixed nutrient layer. The application amount is 0.5-3kg / m 2 , thereby forming a nitrogen-fixing layer. The bacterial liquid containing nitrogen-fixing bacteria is prepared by dissolving nitrogen-fixing bacteria agent in nutrient solution. The nitrogen-fixing bacteria in the nitrogen-fixing bacteria agent mainly include autotrophic nitrogen-fixing bacteria and symbiotic nitrogen-fixing bacteria. Nitrogen-fixing bacteria can form a synergistic relationship with cyanobacteria and plants to build a microecological nitrogen cycle.

[0095] S4. Application of moss skin

[0096] After the semi-carbonized corn cobs loaded with cyanobacteria and nitrogen-fixing bacteria are applied to the sandy land, moss skin is spread on the soil surface (i.e., the nitrogen-fixing layer). The moss skin is taken from the woodland or rock surface near the sandy land, and the moss skin is crushed into pieces with a diameter of no more than 2 cm. Then, the moss skin is drenched with water dissolved with auxin to make a spreading material containing moss skin. The spreading material containing moss skin is spread on the surface of the nitrogen-fixing layer at an application rate of 1-2 kg / m 2 After application, water the sandy land fully to make the water moisten at least 10cm of the surface soil of the sandy land, and at the same time make the dried sludge and water retaining agent fully absorb water, and keep a certain amount of moisture in the surface sandy soil so that cyanobacteria and moss can grow. If there is no natural rainfall, water it artificially every 5-8 days for 30-50 days, so that cyanobacteria and moss can be fully colonized on the semi-carbonized corn cobs.

[0097] S5. Planting of pioneer plants

[0098] Pioneer plant planting adopts the mixed sowing method of various types of plants. Among them, one type is herbaceous plants, such as Bermuda grass and ryegrass. These two plants grow fast and have strong tolerance to the environment. They can take root quickly under the conditions of sufficient nutrition and water. Their roots will wrap the sand particles around the roots during the growth process to form aggregates and enhance water retention. The second type is leguminous plants. Nitrogen-fixing bacteria and leguminous plants can coexist well. Plants are induced to form nodules through rhizobia. Among them, leguminous plants include Junggar leafless beans and sand Zhen thorn beans. They are excellent pioneer sand-fixing plants. The above pioneer plants can be planted 10-20 days after the moss skin is spread. Planting adopts the method of sowing grass seeds. The above pioneer plant seeds are mixed evenly. The seeds are fully soaked in water before sowing to make the seeds absorb water. Appropriate addition of auxin in the water is conducive to the rapid rooting of the seeds after they are sown on the surface of the sand layer. Seed sowing should not be too sparse or too dense. 40-70g / m 2 (calculated as dry seeds) is appropriate.

[0099] Through the above-mentioned sandy land restoration process (the construction method of the "soil + bacteria + algae + moss + plant" microecological system for the restoration of desertified land), based on the above-ground and underground combined fertilization technology in the sandy land restoration process, a pattern of "underground slow-release fertilizer supply" and "above-ground biological fertilizer fixation" has been formed, which can lock the fertility of the sandy land and prevent it from being lost; at the same time, a "soil + bacteria + algae + moss + grass" microecological system is constructed to artificially promote soil development and shorten the evolution time. Through the mutual feedback of fertility improvement, crop growth and root secretions to the cultivated soil, a virtuous cycle system is formed; and deep soil can be repaired and long-term repair can be maintained, improving the repair effect.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reforestation of sandy land, characterized in that: The following steps are involved: Forming holes on the surface of sandy soil, burying stick fertilizer in the holes, forming a stick fertilizer layer containing the stick fertilizer, and a surface sand layer located above the stick fertilizer layer; Applying sludge material on the surface of the surface sand layer, and mixing the sludge material with at least part of the surface sand layer to form a mixed nutrient layer; wherein the sludge material includes dried sludge, fulvic acid, nitrogen fertilizer, nitrification inhibitor and water retaining agent; Applying nitrogen-fixing materials on the surface of the mixed nutrient layer to form a nitrogen-fixing layer; wherein the nitrogen-fixing materials include a carrier, and cyanobacteria and nitrogen-fixing bacteria loaded on the carrier; After applying a spreading material containing moss bark on the surface of the nitrogen-fixing layer, planting pioneer plants on the sandy land; The particle size of the sowing material containing moss skin is less than or equal to 2 cm; and / or, the spreading material containing moss bark contains auxin; And / or, the application amount of the spreading material containing moss skin is 1-2kg / m 2 ; After applying the spreading material containing moss skin on the surface of the nitrogen-fixing layer, water is applied to moisten the soil, and the soil surface thickness is at least 10 cm. After 10-20 days, the pioneer plants are planted on the sandy land; wherein, the sandy land is watered intermittently during the 10-20 days.

2. The method for reforestation of sandy land according to claim 1, characterized in that: The hole has a diameter of 8-10 cm and a depth of 80-100 cm; And / or, the diameter of the fertilizer stick is 6-8 cm and the length is 60-80 cm; and / or, forming a plurality of holes on the surface of the sandy soil, and burying one stick of fertilizer in each hole; And / or, the density of the holes formed on the surface of the sandy soil is 3-9 holes / m 2 ; And / or, the process of burying the fertilizer stick into the hole includes: placing the fertilizer stick into the hole, watering to moisten the surface of the fertilizer stick and then filling with soil, and forming a surface sand layer above the fertilizer stick layer through the filling with soil.

3. The method for reforestation of sandy land according to claim 1 or 2, characterized in that: The preparation process of the stick fertilizer comprises: Mixing organic nutrient soil and compound fertilizer to obtain a first mixture; Controlling the moisture content of the first mixture to be 45-52%, and then adding a binder thereto to obtain a second mixture; Pressing the second mixture into a molded product to obtain a molded product; The molded product is dried to a moisture content of 35% to 40% to obtain the stick fertilizer.

4. The method for reforestation of sandy land according to claim 3, characterized in that: The mass ratio of the organic nutrient soil to the compound fertilizer is (2-5):1; And / or, the compound fertilizer comprises a nitrogen-phosphorus-potassium compound fertilizer, in which the mass percentage of nitrogen is greater than or equal to 15%, the mass percentage of phosphorus is greater than or equal to 15%, and the mass percentage of potassium is greater than or equal to 15%; And / or, the mass percentage of the binder in the second mixture is 2%-3%; and / or, the adhesive comprises water-soluble starch and / or sodium alginate; And / or, the process of adding the binder thereto comprises: mixing the binder with water at a temperature of 40-50° C. to obtain a mixed solution; adding the mixed solution to the first mixture; wherein the mass ratio of the binder to water is 1:(5-10); And / or, the pressing pressure of the pressing molding is 7-12MPa; And / or, the compression molding process includes: gradually pressurizing the second mixture at a pressure increase rate of 1-2 MPa / s until the pressure is reached to a compression pressure, and maintaining the compression pressure for 3-5 seconds to compression mold the second mixture.

5. The method for reforestation of sandy land according to claim 1, characterized in that: In the sludge material, the mass percentage of the dried sludge is 85-95%, the mass percentage of the fulvic acid is 2-3%, the mass percentage of the nitrogen fertilizer is 1-2%, the mass percentage of the nitrification inhibitor is 0.2-0.5%, and the mass percentage of the water retaining agent is 1-1.5%; And / or, the moisture content of the dried sludge is 40-60%; and / or, the particle size of the dried sludge is less than or equal to 0.5 cm; And / or, the application amount of the sludge material is 2-3 kg / m 2 ; And / or, mixing the sludge material with at least a portion of the surface sand layer means mixing the sludge material with a sand layer 10 cm thick above the surface sand layer to form the mixed nutrient layer.

6. The method for reforestation of sandy land according to claim 1, characterized in that: The carrier in the nitrogen-fixing material includes semi-carbonized corn cobs, and the preparation process of the semi-carbonized corn cobs includes: crushing the corn cobs into corn cob particles with a particle size of 0.2-0.5 cm; carbonizing the corn cob particles at 190-220° C. for 30-60 minutes to obtain the semi-carbonized corn cobs; And / or, the preparation process of the nitrogen-fixing material comprises: soaking the carrier in an impregnation solution containing cyanobacteria for 2-5 hours to obtain a carrier loaded with cyanobacteria; spraying a bacterial solution containing nitrogen-fixing bacteria on the carrier loaded with cyanobacteria to load nitrogen-fixing bacteria on the carrier loaded with cyanobacteria to obtain the nitrogen-fixing material; And / or, the nitrogen-fixing bacteria include autotrophic nitrogen-fixing bacteria and / or symbiotic nitrogen-fixing bacteria; And / or, the application amount of the nitrogen-fixing material is 0.5-3 kg / m 2 .

7. The method for reforestation of sandy land according to claim 1, characterized in that: The pioneer plants include herbaceous plants and / or legumes, the herbaceous plants include Cynodon dactylon and / or Lolium, and the legumes include Junggar leafless bean and / or Oxytropis glabra.

8. The method for reforestation of sandy land according to claim 1 or 7, characterized in that: The planting density of the pioneer plants is 40-70g / m 2 .

Images