Desertification control method

Abstract

The invention relates to the technical field of desertification control, and particularly discloses a desertification control method. According to the method, the salt absorption layer is laid in the transplanting and field planting process, the alkali drainage channel water can be directly used for irrigation, the salt absorption layer is used for absorbing salt, the salt content in the alkali drainage channel water is reduced, and the problem that due to the fact that the salt content in the alkali drainage channel water is high, seedlings die is solved.

Description

Technical Field

[0001] The invention relates to the technical field of desertification control, and specifically discloses a method for preventing and controlling desertification. Background Art

[0002] my country's saline-alkali land covers approximately 27 million hectares, of which 6 million hectares are cultivated land, and 21 million hectares are saline-alkali wasteland. These saline-alkali lands are primarily distributed in the inland areas of Northeast China, North China, and Northwest China, as well as in the coastal areas north of the Yangtze River. They are particularly concentrated and contiguous in the oases surrounding the Qaidam Basin and the Tarim Basin, the alluvial plains at the northern foot of the Tianshan Mountains, the Hetao Plain, the Yinchuan Plain, the North China Plain, and the Yellow River Delta.

[0003] Saline-alkali land forms when, under specific natural conditions, soluble salts redistribute horizontally and vertically within the soil, leading to the gradual accumulation of salt in the surface layer of the soil in areas where salt accumulates. Factors such as climate change, poor farming techniques, and rising groundwater levels can all contribute to soil salinization.

[0004] Salinization has severely damaged the land, leading to the emergence of a large number of low- and medium-yield fields. Because the soil contains a large number of anions and cations that are harmful to crops, large areas of soil resources are difficult to utilize, resulting in a decline in the overall agricultural production capacity. Currently, the most effective method for managing saline-alkali soil is to remove salt and alkali by leaching the soil, a method known as salt washing. A drainage and irrigation system is constructed on saline-alkali land, flooding the land with water to dissolve the salt in the soil. Soluble salt and alkali in the surface soil are then drained into the deeper soil layers or flushed out through infiltration, and then discharged into drainage channels through lateral seepage for removal. This method is highly dependent on water resources, consuming more than half of the freshwater resources surrounding the saline-alkali land.

[0005] The drainage volume of saline-alkali land in my country is very large. If the salt and alkali leached out are not scientifically treated, over time, it may lead to serious ecological problems such as secondary salinization of non-salinized land and surface water pollution.

[0006] By purifying the water from saline-alkali drainage canals, brackish water can be recharged into the land, allowing the cultivation of salt-tolerant and economically valuable plants, thus maintaining a perennial green vegetation cover on saline-alkali land. This will fundamentally improve China's overall ecological environment. Generally, using purified saline-alkali drainage canal water for irrigation reduces pollution from fertilizers and pesticides, and in salinized desert areas, pollution is almost zero. Given the tense balance between arable land resources and population growth nationwide, and the widespread impact of varying degrees of agricultural pollution, transforming saline-alkali wasteland into fertile farmland will not only provide new arable land resources for the country but also effectively alleviate the crises of freshwater resources, arable land resources, and salinization and desertification. This will help promote a green, ecological, circular agricultural model, bringing not only significant economic benefits but also significant ecological and social benefits to the country.

[0007] However, at present, the water from the drainage channel needs to pass through a water treatment plant or a water purification pool before it can be re-injected into the land, which is costly and the salt content in the brackish water is still high. Summary of the Invention

[0008] In order to solve the problems in the prior art that the purification cost of drainage channel water recharge is high and the salt content in the purified brackish water is still high, the present invention provides a method for preventing and controlling desertification.

[0009] The present invention provides a method for preventing and controlling desertification using the following technical solutions:

[0010] A method for preventing and controlling desertification comprises the following steps:

[0011] (1) Land preparation and fertilization: Use a rotary tiller to deep plow the land 25-30 cm, apply base fertilizer while preparing the land, and harrow the land to a height difference of less than 5 cm;

[0012] (2) Transplanting and planting: dig planting holes with a diameter of 30-40 cm and a depth of 40-50 cm at a spacing of (1.5-2.5) m × (2.5-3.5) m. Place the roots of healthy and pest-free seedlings into the planting holes, fill the holes with soil up to the root of the seedlings, lay a salt absorption layer, and water them for the first time.

[0013] (3) Laying drip irrigation tape: A drip irrigation tape is fixed on both sides of each row of seedlings. The two drip irrigation tapes are crossed every 3 to 5 seedlings. The distance between the drip irrigation tape emitter and the tree trunk is greater than 15 cm.

[0014] (4) Field management: including irrigation, weeding, and fertilization;

[0015] Wherein, the water used for replenishing in step (2) and the water used for irrigation in step (4) are both water from the drainage canal.

[0016] The present invention can directly use drainage channel water for irrigation by laying a salt absorption layer during the transplanting and planting process. The salt absorption layer absorbs salt, thereby reducing the salt content in the drainage channel water and avoiding the problem of seedling death caused by the high salt content in the drainage channel water.

[0017] Preferably, the salt absorbing layer comprises a first plant fiber layer, a second plant fiber layer and a third plant fiber layer arranged in sequence from top to bottom;

[0018] Aluminum oxide is provided in the first plant fiber layer, and the mass percentage of the aluminum oxide is 1%-99% based on the first plant fiber layer;

[0019] The second plant fiber layer is provided with modified activated carbon, and the mass percentage of the modified activated carbon is 1%-99% based on the second plant fiber layer;

[0020] The third plant fiber layer is provided with modified zinc oxide, and the mass percentage of the modified zinc oxide is 1%-5% based on the third plant fiber layer.

[0021] The present invention uses a plant fiber layer provided with aluminum oxide for the first filtration, which can preliminarily intercept pollutants such as organic matter, nitrogen, phosphorus, silt and algae and other plankton; the present invention uses a plant fiber layer provided with modified activated carbon for the second filtration, which can adsorb some heavy metal salts, such as copper salts, lead salts, cadmium salts, and chromium salts; the present invention uses a plant fiber layer provided with modified zinc oxide for the third filtration, which can adsorb some remaining heavy metal salts as well as sulfates and phosphates, effectively reducing the salt content in the drainage channel water and avoiding the problem of seedling death caused by the high salt content in the drainage channel water.

[0022] Preferably, the preparation method of the modified activated carbon comprises the following steps:

[0023] Step 1: ball milling the modified activated carbon, heating it to 930-950°C for high-temperature pyrolysis to obtain primary modified activated carbon;

[0024] Step 2: uniformly mix the primary modified activated carbon and the composite treatment liquid, ultrasonicate for 5-10 min at 600-800 W and 40-60 kHz, separate the solid and liquid, and dry to obtain the intermediate modified activated carbon;

[0025] Step 3: Immersing the intermediate modified activated carbon in a strong alkaline solution at 70-90° C., sieving, and calcining the sieve material at a temperature of 250-350° C. in a low oxygen environment to obtain the treated regenerated modified activated carbon;

[0026] The composite treatment solution comprises the following raw material components in percentage by weight: 1%-5% citric acid, 60%-70% ethanol, 5%-10% persulfate, 5%-10% hydrogen peroxide and the balance water.

[0027] The present invention can effectively control the particle size of the modified activated carbon by limiting the frequency and power of ultrasound and limiting the high ethanol content in the composite treatment liquid, thereby avoiding complete destruction of the structure of the activated carbon due to ultrasonic heating.

[0028] Preferably, in step 1, the temperature is raised in stages, wherein the first stage is to raise the temperature to 230-260°C and keep warm for 20-50 minutes; the second stage is to raise the temperature to 560-590°C and keep warm for 30-100 minutes; the third stage is to raise the temperature to 930-950°C; and / or

[0029] In step 1, the high temperature pyrolysis time is 30-50 minutes.

[0030] Preferably, the staged heating is performed by programmed heating, wherein the heating rate of the first stage is 5-10°C / min; the heating rate of the second stage is 10-15°C / min; and the heating rate of the third stage is 20-25°C / min.

[0031] Preferably, the preparation method of the modified zinc oxide comprises the following steps:

[0032] Step 1): immersing zinc oxide in a methyl silicone oil n-hexane solvent and stirring uniformly to prepare a mixed solution;

[0033] Step 2): evaporating the mixed solution obtained in step 1) to dryness, and drying it in an oven to obtain zinc oxide with methyl silicone oil deposited thereon;

[0034] Step 3): placing the zinc oxide with methyl silicone oil deposited thereon obtained in step 2) in a muffle furnace and calcining it at high temperature to convert the methyl silicone oil into silicon dioxide, thereby obtaining zinc oxide with surface silicon deposition modification;

[0035] In step 3), the high-temperature calcination is carried out under the following conditions: in an oxygen-rich environment, the temperature is raised to 500° C. at a rate of 5° C. / min and maintained for 3 hours.

[0036] Preferably, the mass ratio of zinc oxide to methyl silicone oil in step 1) is (0.5-1):1, the mass volume ratio of methyl silicone oil to n-hexane solvent is 1 g:5 mL, and the mass fraction of methyl silicone oil is 10%-30%.

[0037] Preferably, the evaporation step in step 2) is carried out at a water bath temperature of 60-90°C.

[0038] In summary, the present invention includes at least one of the following beneficial technical effects:

[0039] 1. The desertification prevention and control method provided by the present invention can directly use drainage channel water for irrigation by laying a salt absorption layer during the transplanting and planting process. The absorption of salt by the salt absorption layer reduces the salt content in the drainage channel water.

[0040] 2. The present invention uses a plant fiber layer provided with aluminum oxide for the first filtration, which can preliminarily intercept pollutants such as organic matter, nitrogen, phosphorus, silt and algae and other plankton; the present invention uses a plant fiber layer provided with modified activated carbon for the second filtration, which can adsorb some heavy metal salts, such as copper salts, lead salts, cadmium salts, and chromium salts; the present invention uses a plant fiber layer provided with modified zinc oxide for the third filtration, which can adsorb some of the remaining heavy metal salts as well as sulfates and phosphates, effectively reducing the salt content in the drainage channel water and avoiding the problem of seedling death due to the high salt content in the drainage channel water. DETAILED DESCRIPTION

[0041] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiment is only one embodiment of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] Example 1

[0043] A method for preparing modified activated carbon comprises the following steps:

[0044] Step 1, 500g of hazardous waste modified activated carbon was ball-milled at a speed of 350rpm for 150min, and the temperature was raised to 940°C in a staged heating manner for high-temperature pyrolysis, wherein the first stage was heated to 250°C at a heating rate of 10°C / min and kept warm for 35min; then heated to 580°C at a heating rate of 15°C / min and kept warm for 80min; finally, heated to 940°C at a heating rate of 24°C / min, kept warm for 40min, and cooled to room temperature to obtain 442g of primary modified activated carbon;

[0045] Step 2: The primary modified activated carbon was evenly mixed with 1100 mL of the composite treatment liquid, ultrasonically treated at 600 W and 50 kHz for 7 min, solid-liquid separation was performed, and dried at 90 ° C for 3 h to obtain 401 g of intermediate modified activated carbon; wherein the composite treatment liquid includes the following raw material components in the following mass percentages: 3% citric acid, 65% ethanol, 8% ammonium persulfate, 6% hydrogen peroxide and 18% water.

[0046] Step 3: Immerse the intermediate modified activated carbon in 1400 mL of 0.5 mol / L sodium hydroxide solution at 85°C, sieve, and calcine the sieve material at a high temperature of 8% oxygen content and 320°C for 2.5 hours to obtain the treated regenerated modified activated carbon.

[0047] Example 2

[0048] A method for preparing modified activated carbon comprises the following steps:

[0049] Step 1, 500g of hazardous waste modified activated carbon was ball milled at a speed of 300rpm for 150min, and the temperature was raised to 930℃ in a staged heating manner for high-temperature pyrolysis. In the first stage, the temperature was raised to 230℃ at a heating rate of 5℃ / min and kept warm for 50min; then the temperature was raised to 550℃ at a heating rate of 10℃ / min and kept warm for 100min; finally, the temperature was raised to 930℃ at a heating rate of 20℃ / min, kept warm for 35min, and cooled to room temperature to obtain 435g of primary modified activated carbon;

[0050] Step 2: The primary modified activated carbon was evenly mixed with 1000 mL of a composite treatment liquid, ultrasonicated at 700 W and 50 kHz for 7 min, solid-liquid separated, and dried at 85 ° C for 4 h to obtain 386 g of intermediate modified activated carbon; wherein the composite treatment liquid comprises the following raw material components in the following mass percentages: 4% citric acid, 65% ethanol, 6% sodium persulfate, 7% hydrogen peroxide, and 18% water.

[0051] Step 3: Immerse the intermediate modified activated carbon in 1500 mL of a 0.8 mol / L sodium hydroxide solution at 90°C, sieve, and calcine the sieve material at a high temperature of 300°C for 3 hours at an oxygen content of 5% to obtain the treated regenerated modified activated carbon.

[0052] Example 3

[0053] A method for preparing modified zinc oxide comprises the following steps:

[0054] 1) Dissolve 5 g of 20% by mass methyl silicone oil in 20 mL of n-hexane solvent, then add 4 g of zinc oxide and stir well to prepare a mixed solution;

[0055] 2) evaporating the mixed solution obtained in step 1) to dryness in a water bath at 75° C. and drying in an oven to obtain zinc oxide deposited with methyl silicone oil;

[0056] 3) The zinc oxide with deposited methyl silicone oil obtained in step 2) is placed in a muffle furnace, and the temperature is raised to 500° C. at a rate of 5° C. / min under oxygen-rich conditions and maintained for 3 hours to convert the methyl silicone oil into silicon dioxide to obtain modified zinc oxide.

[0057] Example 4

[0058] A method for preparing modified zinc oxide comprises the following steps:

[0059] 1) Dissolve 5 g of 10% methyl silicone oil in 25 mL of n-hexane solvent, then add 5 g of zinc oxide and stir well to prepare a mixed solution;

[0060] 2) evaporating the mixed solution obtained in step 1) to dryness in a water bath at 90° C. and drying in an oven to obtain zinc oxide deposited with methyl silicone oil;

[0061] 3) The zinc oxide with deposited methyl silicone oil obtained in step 2) is placed in a muffle furnace, and the temperature is raised to 500° C. at a rate of 5° C. / min under oxygen-rich conditions and maintained for 3 hours to convert the methyl silicone oil into silicon dioxide to obtain modified zinc oxide.

[0062] Example 5

[0063] A method for preventing and controlling desertification comprises the following steps:

[0064] (1) Land preparation and fertilization: A desert plot with an uncultivated, flat terrain, pH value of 8.43, organic matter of 3.5 g / kg, total nitrogen of 0.17 g / kg, alkaline nitrogen of 17 mg / kg, available potassium of 36 mg / kg, available phosphorus of 4.79 mg / kg, and water-soluble salt of 0.36 g / kg was selected as the experimental site. The experimental site was plowed 30 cm deep using a rotary tiller, and 20,000 kg / hm2 of manure was applied during land preparation. 2 , urea (46.4% N) 2000kg / hm 2 , diammonium phosphate (N-P2O5-K2O ≥ 64.05, 18-46-0) 2000 kg / hm 2 , potassium magnesium sulfate fertilizer (K2O ≥ 24%, Mg ≥ 6.0%, S ≥ 16.00) 1000kg / hm 2 After harrowing, the height difference is less than 5cm.

[0065] (2) Transplantation and planting: Select healthy and pest-free seedlings, dip their roots in 250mg / L rooting powder solution and set aside; dig planting holes with a diameter of 35cm and a depth of 40cm according to the row spacing of 2m×3m; place the roots of the seedlings in the planting holes, first fill half of the topsoil, lift the seedlings upward to stretch the roots, and then fill the subsoil; fill the soil while stepping on it; fill the soil to the root of the seedlings, cover the soil slightly above the ground, lay a salt absorption layer, and irrigate for the first time after planting, with an irrigation volume of 200m 3 / hm 2 ;

[0066] The salt absorbing layer includes a first plant fiber layer, a second plant fiber layer and a third plant fiber layer arranged in sequence from top to bottom;

[0067] Aluminum oxide is provided in the first plant fiber layer, and the mass percentage of the aluminum oxide is 1% based on the first plant fiber layer;

[0068] The second plant fiber layer is provided with modified activated carbon, and the mass percentage of the modified activated carbon is 1% based on the second plant fiber layer, wherein the modified activated carbon is the modified activated carbon prepared in Example 1;

[0069] Modified zinc oxide is provided in the third plant fiber layer. The mass percentage of the modified zinc oxide is 1% based on the third plant fiber layer. The modified activated carbon is the modified zinc oxide prepared in Example 3.

[0070] (3) Laying drip irrigation tape: Customize the drip irrigation tape with the matching dripper spacing according to the spacing between the seedlings. A drip irrigation tape is fixed on both sides of each row of seedlings. The two drip irrigation tapes are crossed every 3-5 seedlings. The distance between the dripper position of the drip irrigation tape and the tree trunk is greater than 15 cm.

[0071] (4) Field management: The second irrigation is carried out on the 25th day after transplanting and planting, with a drip irrigation volume of 250m 3 / hm 2 , and topdressing urea and potassium dihydrogen phosphate at 750 kg / hm 2 ;

[0072] The third irrigation was carried out after 30 days, with a drip irrigation volume of 250m 3 / hm 2 ;

[0073] The fourth irrigation was carried out after 35 days, with a drip irrigation volume of 250m 3 / hm 2 , and apply 1200kg / hm2 of compound fertilizer with a nitrogen, phosphorus and potassium ratio of 1:1:1 2 ;

[0074] The fifth irrigation after 25 days, the drip irrigation volume is 300m 3 / hm 2 , and apply 1200kg / hm2 of compound fertilizer with a nitrogen, phosphorus and potassium ratio of 1:1:2 2 ;

[0075] The sixth irrigation after 35 days, the drip irrigation volume is 300m 3 / hm 2 ;

[0076] The seventh irrigation after 35 days, the drip irrigation volume is 300m 3 / hm 2 ;

[0077] Shallow tillage and weeding should be carried out one week after each irrigation.

[0078] Example 6

[0079] A method for preventing and controlling desertification comprises the following steps:

[0080] (1) Land preparation and fertilization: A desert plot with an uncultivated, flat terrain, pH value of 8.43, organic matter of 3.5 g / kg, total nitrogen of 0.17 g / kg, alkaline nitrogen of 17 mg / kg, available potassium of 36 mg / kg, available phosphorus of 4.79 mg / kg, and water-soluble salt of 0.36 g / kg was selected as the experimental site. The experimental site was plowed 30 cm deep using a rotary tiller, and 20,000 kg / hm2 of manure was applied during land preparation. 2 , urea (46.4% N) 2000kg / hm 2 , diammonium phosphate (N-P2O5-K2O ≥ 64.05, 18-46-0) 2000 kg / hm 2 , potassium magnesium sulfate fertilizer (K2O ≥ 24%, Mg ≥ 6.0%, S ≥ 16.00) 1000kg / hm 2 After harrowing, the height difference is less than 5cm.

[0081] (2) Transplantation and planting: Select healthy and pest-free seedlings, dip their roots in 250mg / L rooting powder solution and set aside; dig planting holes with a diameter of 35cm and a depth of 40cm according to the row spacing of 2m×3m; place the roots of the seedlings in the planting holes, first fill half of the topsoil, lift the seedlings upward to stretch the roots, and then fill the subsoil; fill the soil while stepping on it; fill the soil to the root of the seedlings, cover the soil slightly above the ground, lay a salt absorption layer, and irrigate for the first time after planting, with an irrigation volume of 200m 3 / hm 2 ;

[0082] The salt absorbing layer includes a first plant fiber layer, a second plant fiber layer and a third plant fiber layer arranged in sequence from top to bottom;

[0083] Aluminum oxide is provided in the first plant fiber layer, and the mass percentage of the aluminum oxide is 99% based on the first plant fiber layer;

[0084] The second plant fiber layer is provided with modified activated carbon, and the mass percentage of the modified activated carbon is 99% based on the second plant fiber layer, wherein the modified activated carbon is the modified activated carbon prepared in Example 1;

[0085] The third plant fiber layer is provided with modified zinc oxide. The mass percentage of the modified zinc oxide is 5% based on the third plant fiber layer. The modified activated carbon is the modified zinc oxide prepared in Example 3.

[0086] (3) Laying drip irrigation tape: Customize the drip irrigation tape with the matching dripper spacing according to the spacing between the seedlings. A drip irrigation tape is fixed on both sides of each row of seedlings. The two drip irrigation tapes are crossed every 3-5 seedlings. The distance between the dripper position of the drip irrigation tape and the tree trunk is greater than 15 cm.

[0087] (4) Field management: The second irrigation is carried out on the 25th day after transplanting and planting, with a drip irrigation volume of 250m 3 / hm 2 , and topdressing urea and potassium dihydrogen phosphate at 750 kg / hm 2 ;

[0088] The third irrigation was carried out after 30 days, with a drip irrigation volume of 250m 3 / hm 2 ;

[0089] The fourth irrigation was carried out after 35 days, with a drip irrigation volume of 250m 3 / hm 2 , and apply 1200kg / hm2 of compound fertilizer with a nitrogen, phosphorus and potassium ratio of 1:1:1 2 ;

[0090] The fifth irrigation after 25 days, the drip irrigation volume is 300m 3 / hm 2 , and apply 1200kg / hm2 of compound fertilizer with a nitrogen, phosphorus and potassium ratio of 1:1:2 2 ;

[0091] The sixth irrigation after 35 days, the drip irrigation volume is 300m 3 / hm 2 ;

[0092] The seventh irrigation after 35 days, the drip irrigation volume is 300m 3 / hm 2 ;

[0093] Shallow tillage and weeding should be carried out one week after each irrigation.

[0094] Example 7

[0095] A method for preventing and controlling desertification comprises the following steps:

[0096] (1) Land preparation and fertilization: A desert plot with an uncultivated, flat terrain, pH value of 8.43, organic matter of 3.5 g / kg, total nitrogen of 0.17 g / kg, alkaline nitrogen of 17 mg / kg, available potassium of 36 mg / kg, available phosphorus of 4.79 mg / kg, and water-soluble salt of 0.36 g / kg was selected as the experimental site. The experimental site was plowed 30 cm deep using a rotary tiller, and 20,000 kg / hm2 of manure was applied during land preparation. 2, urea (46.4% N) 2000kg / hm 2 , diammonium phosphate (N-P2O5-K2O ≥ 64.05, 18-46-0) 2000 kg / hm 2 , potassium magnesium sulfate fertilizer (K2O ≥ 24%, Mg ≥ 6.0%, S ≥ 16.00) 1000kg / hm 2 After harrowing, the height difference is less than 5cm.

[0097] (2) Transplantation and planting: Select healthy and pest-free seedlings, dip their roots in 250mg / L rooting powder solution and set aside; dig planting holes with a diameter of 35cm and a depth of 40cm according to the row spacing of 2m×3m; place the roots of the seedlings in the planting holes, first fill half of the topsoil, lift the seedlings upward to stretch the roots, and then fill the subsoil; fill the soil while stepping on it; fill the soil to the root of the seedlings, cover the soil slightly above the ground, lay a salt absorption layer, and irrigate for the first time after planting, with an irrigation volume of 200m 3 / hm 2 ;

[0098] The salt absorbing layer includes a first plant fiber layer, a second plant fiber layer and a third plant fiber layer arranged in sequence from top to bottom;

[0099] Aluminum oxide is provided in the first plant fiber layer, and the mass percentage of the aluminum oxide is 50% based on the first plant fiber layer;

[0100] The second plant fiber layer is provided with modified activated carbon, and the mass percentage of the modified activated carbon is 50% based on the second plant fiber layer, wherein the modified activated carbon is the modified activated carbon prepared in Example 2;

[0101] The third plant fiber layer is provided with modified zinc oxide. The mass percentage of the modified zinc oxide is 3% based on the third plant fiber layer. The modified activated carbon is the modified zinc oxide prepared in Example 4.

[0102] (3) Laying drip irrigation tape: Customize the drip irrigation tape with the matching dripper spacing according to the spacing between the seedlings. A drip irrigation tape is fixed on both sides of each row of seedlings. The two drip irrigation tapes are crossed every 3-5 seedlings. The distance between the dripper position of the drip irrigation tape and the tree trunk is greater than 15 cm.

[0103] (4) Field management: The second irrigation is carried out on the 25th day after transplanting and planting, with a drip irrigation volume of 250m 3 / hm 2 , and topdressing urea and potassium dihydrogen phosphate at 750 kg / hm 2 ;

[0104] The third irrigation was carried out after 30 days, with a drip irrigation volume of 250m 3 / hm2 ;

[0105] The fourth irrigation was carried out after 35 days, with a drip irrigation volume of 250m 3 / hm 2 , and apply 1200kg / hm2 of compound fertilizer with a nitrogen, phosphorus and potassium ratio of 1:1:1 2 ;

[0106] The fifth irrigation after 25 days, the drip irrigation volume is 300m 3 / hm 2 , and apply 1200kg / hm2 of compound fertilizer with a nitrogen, phosphorus and potassium ratio of 1:1:2 2 ;

[0107] The sixth irrigation after 35 days, the drip irrigation volume is 300m 3 / hm 2 ;

[0108] The seventh irrigation after 35 days, the drip irrigation volume is 300m 3 / hm 2 ;

[0109] Shallow tillage and weeding should be carried out one week after each irrigation.

[0110] The desertification prevention and control methods provided in Examples 5-7 were used to carry out a seedling planting experiment in arid areas. The survival rates of each group were calculated two months after the seedlings were planted. The data obtained are shown in Table 1:

[0111] Table 1 Statistical table of seedling survival rates in seedling planting experiments of Examples 5-7

[0112] project Seedling survival rate Example 5 98.53％ Example 6 97.46％ Example 7 98.60％

[0113] As can be seen from Table 1, the desertification control method provided by the present invention can effectively ensure the survival rate of seedlings. Therefore, the present invention achieves the goal of using drainage canal water to plant seedlings, reduces dependence on freshwater resources and underground saltwater resources, and expands the space for afforestation in desert marginal areas.

[0114] The above are all preferred embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preventing and controlling desertification, characterized in that: The following steps are involved: (1) Land preparation and fertilization: Use a rotary tiller to deep plow the land 25-30 cm, apply base fertilizer while preparing the land, and harrow the land to a height difference of less than 5 cm; (2) Transplanting and planting: dig planting holes with a diameter of 30-40 cm and a depth of 40-50 cm at a spacing of (1.5-2.5) m × (2.5-3.5) m. Place the roots of healthy and pest-free seedlings into the planting holes, fill the holes with soil up to the root of the seedlings, lay a salt absorption layer, and water them for the first time. (3) Laying drip irrigation tape: A drip irrigation tape is fixed on both sides of each row of seedlings. The two drip irrigation tapes are crossed every 3 to 5 seedlings. The distance between the drip irrigation tape emitter and the tree trunk is greater than 15 cm. (4) Field management: including irrigation, weeding, and fertilization; Wherein, the water used for replenishing in step (2) and the water used for irrigation in step (4) are both water from the drainage canal.

2. A method for combating desertification according to claim 1, characterized in that: The salt absorbing layer comprises a first plant fiber layer, a second plant fiber layer and a third plant fiber layer arranged in sequence from top to bottom; Aluminum oxide is provided in the first plant fiber layer, and the mass percentage of the aluminum oxide is 1%-99% based on the first plant fiber layer; The second plant fiber layer is provided with modified activated carbon, and the mass percentage of the modified activated carbon is 1%-99% based on the second plant fiber layer; The third plant fiber layer is provided with modified zinc oxide, and the mass percentage of the modified zinc oxide is 1%-5% based on the third plant fiber layer.

3. A method for combating desertification according to claim 2, characterized in that: The preparation method of the modified activated carbon comprises the following steps: Step 1: ball milling the modified activated carbon, heating it to 930-950°C for high-temperature pyrolysis to obtain primary modified activated carbon; Step 2: uniformly mix the primary modified activated carbon and the composite treatment liquid, ultrasonicate for 5-10 min at 600-800 W and 40-60 kHz, separate the solid and liquid, and dry to obtain the intermediate modified activated carbon; Step 3: Immersing the intermediate modified activated carbon in a strong alkaline solution at 70-90° C., sieving, and calcining the sieve material at a temperature of 250-350° C. in a low oxygen environment to obtain the treated regenerated modified activated carbon; The composite treatment solution comprises the following raw material components in percentage by weight: 1%-5% citric acid, 60%-70% ethanol, 5%-10% persulfate, 5%-10% hydrogen peroxide and the balance water.

4. A method for combating desertification according to claim 3, characterized in that: In step 1, the temperature is raised in stages, wherein the first stage is to raise the temperature to 230-260°C and keep it for 20-50 minutes; the second stage is to raise the temperature to 560-590°C and keep it for 30-100 minutes; the third stage is to raise the temperature to 930-950°C; and / or In step 1, the high temperature pyrolysis time is 30-50 minutes.

5. A method for combating desertification according to claim 4, characterized in that: The staged heating is all performed in a programmed heating manner, wherein the heating rate of the first stage is 5-10°C / min; the heating rate of the second stage is 10-15°C / min; and the heating rate of the third stage is 20-25°C / min.

6. A method for combating desertification according to claim 2, characterized in that: The preparation method of the modified zinc oxide comprises the following steps: Step 1): immersing zinc oxide in a methyl silicone oil n-hexane solvent and stirring uniformly to prepare a mixed solution; Step 2): evaporating the mixed solution obtained in step 1) to dryness, and drying it in an oven to obtain zinc oxide with methyl silicone oil deposited thereon; Step 3): placing the zinc oxide with methyl silicone oil deposited thereon obtained in step 2) in a muffle furnace and calcining it at high temperature to convert the methyl silicone oil into silicon dioxide, thereby obtaining zinc oxide with surface silicon deposition modification; In step 3), the high-temperature calcination is carried out under the following conditions: in an oxygen-rich environment, the temperature is raised to 500° C. at a rate of 5° C. / min and maintained for 3 hours.

7. A method for combating desertification according to claim 6, characterized in that: The mass ratio of zinc oxide to methyl silicone oil in step 1) is (0.5-1):1, the mass volume ratio of methyl silicone oil to n-hexane solvent is 1g:5mL, and the mass fraction of methyl silicone oil is 10%-30%.

8. The method for preventing and controlling desertification according to claim 7, characterized in that: The evaporation step in step 2) is carried out at a water bath temperature of 60-90°C.