Saline-alkali soil conditioner and method for improving saline-alkali soil by using same

Abstract

The invention discloses a saline-alkali soil conditioner and a method for improving saline-alkali soil by using the saline-alkali soil conditioner, and relates to the technical field of soil improvement. The saline-alkali soil conditioner is prepared from desulfurized gypsum, furfural residues, diatomite, boric acid, a compound microbial agent and a specific nonionic macromolecular polymer, and specific monomers are copolymerized at a certain ratio to obtain the nonionic macromolecular polymer; furthermore, the nonionic polymer and other improved components are combined and applied to the saline-alkali soil, so that the remarkable salt and alkali reducing effects are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of soil improvement, and in particular to a saline-alkali soil improver and a method for improving saline-alkali soil. Background Art

[0002] All kinds of saline-alkali soils are formed under certain natural conditions. The essence of their formation is mainly the horizontal and vertical redistribution of various soluble salts on the ground, so that salt gradually accumulates on the soil surface. The main factors affecting the formation of saline-alkali soil are: climate conditions, terrain conditions, the influence of rivers and seawater, etc.

[0003] Specifically, in the arid and semi-arid areas of Northeast my country, Northwest China, and North China, the precipitation is small and the evaporation is large, so the salt dissolved in the water tends to accumulate on the soil surface. In summer, the rainfall is abundant and concentrated, and a large amount of soluble salts infiltrate into the lower layer or flow away with the water. This is the "desalination" season; in spring, the surface water evaporates strongly, and the salt in the groundwater gathers on the soil surface with the rise of capillary water. This is the main "re-salting" season. The saline-alkali soil in Northeast China, North China, and semi-arid areas has an obvious "re-salting" season. The height of the terrain also has a great influence on the formation of saline-alkali soil. The height of the terrain directly affects the movement of surface water and groundwater, which is closely related to the movement and accumulation of salt. From the perspective of the terrain, water-soluble salts move from high to low with water and accumulate in low-lying areas. Saline-alkali soil is mainly distributed in inland basins, mountain depressions, and flat plains with poor drainage, such as the Songliao Plain. From the perspective of small terrain (local scope), the accumulation of salt in soil is the opposite of that in large terrain, and salt tends to accumulate in small convex parts of the soil. The coarseness and fineness of the texture can affect the speed and height of the movement of soil capillary water. Generally speaking, the capillary water of loamy soil rises faster and higher, while sandy soil and clay accumulate salt more slowly. The key issues affecting soil salinity and alkalinity are the height of the groundwater level and the degree of groundwater mineralization. A high groundwater level and high mineralization make it easy for salt to accumulate. In addition, the land on both sides of rivers and channels has its groundwater level raised due to lateral infiltration of river water, which promotes salt accumulation. Coastal saline-alkali soil can be formed in coastal areas due to seawater infiltration.

[0004] At present, there have been some studies on the use of polymers to improve soil. For example, Chinese patent CN106748540A discloses a conditioner for high-nutrient salinized soil and its preparation method and application. The conditioner is composed of biochar, nonionic polyacrylamide, anionic polyacrylamide, cationic polyacrylamide, lignite and diatomaceous earth; the mass ratio of the biochar, the nonionic polyacrylamide, the anionic polyacrylamide, the cationic polyacrylamide, the lignite and the diatomaceous earth is 5-10:2-4:2-4:1-3:3-5:1. The conditioner of the present invention solves a series of problems caused by salinization on the soil, such as poor soil physical properties, high ion content and low soil quality, and can reduce soil bulk density and increase soil porosity, which is beneficial to the exchange of water, gas, heat, etc. in the soil to improve soil fertility, while reducing the salt ion content and total salt content, reducing its harm to soil and crops, thereby increasing crop yields.

[0005] There is a lack of research on non-ionic polymers as soil conditioners, but non-ionic polymers also have considerable improvement effects in soil. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a saline-alkali soil conditioner and a method for improving saline-alkali soil, using specific monomers to copolymerize in a certain proportion to obtain a non-ionic macromolecular polymer, and further combining the non-ionic polymer with other improvement components and applying it to saline-alkali soil to achieve significant salt and alkali reduction effects.

[0007] To achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0008] On the one hand, the present invention provides a saline-alkali soil conditioner, comprising: desulfurized gypsum, furfural slag, diatomaceous earth, boric acid, composite microbial agent and non-ionic high molecular polymer.

[0009] Preferably, the saline-alkali soil conditioner comprises, by weight: 30-150 parts of desulfurized gypsum, 20-80 parts of furfural slag, 10-40 parts of diatomaceous earth, 1-10 parts of boric acid, 0.1-5 parts of composite microbial agent and 1-10 parts of non-ionic high polymer.

[0010] More preferably, the saline-alkali soil conditioner comprises, by weight: 40-100 parts of desulfurized gypsum, 30-60 parts of furfural slag, 10-30 parts of diatomaceous earth, 2-8 parts of boric acid, 0.5-2 parts of composite microbial agent and 3-8 parts of non-ionic high polymer.

[0011] Most preferably, the saline-alkali soil conditioner comprises, by weight: 60 parts of desulfurized gypsum, 50 parts of furfural slag, 20 parts of diatomaceous earth, 5 parts of boric acid, 1 part of composite microbial agent and 5 parts of non-ionic high polymer.

[0012] Preferably, the method for preparing the nonionic high molecular polymer comprises the following steps:

[0013] Mix water, acrylamide, fatty alcohol polyoxyethylene ether and siloxane, adjust the temperature to 20-35°C, add redox initiator composition, carry out polymerization reaction for 2-5h, raise the temperature to 50-75°C and keep the temperature for 0.5-2h, and dry the product to obtain the non-ionic macromolecule.

[0014] Preferably, the mass ratio of acrylamide, fatty alcohol polyoxyethylene ether and siloxane is 20-30:5-10:1-3, most preferably 25:5:3.

[0015] Preferably, based on 150 g of water, the amount of acrylamide added is 20-50 g, more preferably 25 g.

[0016] Preferably, based on 150g of water, the added amount of the fatty alcohol polyoxyethylene ether is 1-10g, more preferably 5g.

[0017] Preferably, based on 150 g of water, the amount of siloxane added is 0.3-5 g, more preferably 3 g.

[0018] Preferably, the adjustment temperature is 28°C.

[0019] Preferably, based on 150 g of water, the amount of the redox initiator composition added is 0.5-2 g, more preferably 1.5 g.

[0020] Preferably, the redox initiator composition comprises ammonium persulfate and 2,2'-azobis(N'-2-amidinopropane)-dihydroxide, and further preferably, the mass ratio of ammonium persulfate to 2,2'-azobis(N'-2-amidinopropane)-dihydroxide is 1-5:1-5, and further preferably 2:1.

[0021] Preferably, the polymerization reaction time is 3 hours.

[0022] Preferably, after the polymerization reaction, the temperature is raised to 62° C. and then kept at that temperature for 1 hour.

[0023] As a preferred example of the present invention, the method for preparing the nonionic macromolecule comprises the following steps:

[0024] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 5g of fatty alcohol polyoxyethylene ether, and 3g of siloxane, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, and add 1.5g of redox initiator composition, which is composed of ammonium persulfate and 2,2'-azobis(,N'-2-amidinopropane)-dihydroxide in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry, crush and grind the product to obtain the non-ionic macromolecule.

[0025] Preferably, the molecular weight of the nonionic macromolecule is 900,000-1.2 million.

[0026] In yet another aspect, the present invention provides use of the above-mentioned nonionic macromolecules in improving saline-alkali land.

[0027] Preferably, in the application, the nonionic macromolecule is used by broadcasting or spraying. Broadcasting is more preferred.

[0028] On the other hand, the present invention provides a method for preparing the above-mentioned saline-alkali land soil conditioner, comprising the following steps: uniformly mixing reduced amounts of desulfurized gypsum, furfural slag, diatomaceous earth, boric acid, composite microbial agent and non-ionic high molecular polymer to obtain the soil conditioner.

[0029] Finally, the present invention provides a method for repairing soil, comprising the step of applying the above-mentioned saline-alkali soil conditioner to the soil.

[0030] Preferably, the amount applied is 200-500 kg / mu, more preferably 350 kg / mu.

[0031] The beneficial effects of the present invention are:

[0032] The present invention uses acrylamide, fatty alcohol polyoxyethylene ether, and siloxane to copolymerize to prepare nonionic macromolecules, obtain nonionic macromolecules with large molecular weight, and side-link fatty alcohol polyoxyethylene ether to improve the spatial packaging ability and chelating ability of the macromolecules. At the same time, the introduction of siloxane can ensure the stability of the macromolecular polymer and improve the long-term effect in the soil. The nonionic macromolecule is prepared into a soil improver in combination with a specific component, and is applied to saline-alkali soil, which has a long-term salt and alkali reduction effect. DETAILED DESCRIPTION

[0033] In order to make the technical means, creative features, purpose and efficacy of the present invention easy to understand, the present invention is further explained in conjunction with specific embodiments below, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work all belong to the protection scope of the present invention. In the following embodiments, unless otherwise specified, the operating methods used are conventional operating methods, the equipment used are conventional equipment, and the equipment materials used in each embodiment are the same.

[0034] Example 1

[0035] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 5g of fatty alcohol polyoxyethylene ether, and 3g of siloxane, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic polymer.

[0036] Example 2

[0037] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 20g of acrylamide, 10g of fatty alcohol polyoxyethylene ether, and 0.3g of siloxane, mix evenly, adjust the temperature to 35°C, pass nitrogen for 30 minutes, add 0.05g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 2 hours, heat to 75°C and keep warm for 2 hours, dry and crush the product to obtain the non-ionic polymer.

[0038] Example 3

[0039] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 50g of acrylamide, 1g of fatty alcohol polyoxyethylene ether, and 5g of siloxane, mix evenly, adjust the temperature to 20°C, pass nitrogen for 30 minutes, add 0.2g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 5 hours, heat to 75°C and keep warm for 0.5 hours, dry and crush the product to obtain the non-ionic polymer.

[0040] Comparative Example 1

[0041] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, and 5g of fatty alcohol polyoxyethylene ether, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, and add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic polymer.

[0042] Comparative Example 2

[0043] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 5g of dimethylaminoethyl methacrylate, and 3g of siloxane, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic high molecular polymer.

[0044] Comparative Example 3

[0045] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 5g of fatty alcohol polyoxyethylene ether, and 2g of acrylic acid, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic high molecular polymer.

[0046] Comparative Example 4

[0047] In a four-necked bottle with a reflux condenser, a thermometer and a nitrogen pipe, add 150g of deionized water, 25g of acrylamide, 15g of fatty alcohol polyoxyethylene ether, and 10g of siloxane, mix evenly, adjust the temperature to 28°C, pass nitrogen for 30 minutes, add 0.15g of redox initiation composition, which is a combination of ammonium persulfate and potassium bisulfite in a mass ratio of 2:1. Continue to pass nitrogen for 10 minutes, seal the container for reaction, and after 3 hours, heat to 62°C and keep warm for 1 hour, dry and crush the product to obtain the non-ionic polymer.

[0048] Results

[0049] 1. Polymer index

[0050] Testing method: Molecular weight and monomer residue were determined according to GB / T 17514-2017. The results are as follows:

[0051]

[0052] The results show that the monomer residue in Comparative Example 4 is relatively large.

[0053] 2. Inspection of the effect of saline-alkali land improvement

[0054] The salt and alkali reduction effects of the polyacrylamide derivatives prepared in the examples and comparative examples were determined by pot tests. The experiment used a Vashvili pot, and the soil was from saline-alkali soil in the Ordos area of ​​the Inner Mongolia Autonomous Region, which was sieved through a 2 mm sieve and air-dried for later use. The initial soil pH value was determined to be 9.30 and the soil salt content was 6.11 g / kg.

[0055] The commercially available nonionic polyacrylamide, the nonionic high molecular polymer prepared in Examples 1-3 and Comparative Examples 1-4 were respectively mixed uniformly with the remaining ingredients according to the following formula to prepare a soil conditioner: 60 parts of desulfurized gypsum, 50 parts of furfural slag, 20 parts of diatomaceous earth, 5 parts of boric acid, 1 part of composite microbial agent (EM agent of Shandong Beijia Biological), and 5 parts of nonionic high molecular polymer.

[0056] Soil conditioner No. 0: no polymer added (60 parts of desulfurized gypsum, 50 parts of furfural residue, 20 parts of diatomaceous earth, 5 parts of boric acid, 1 part of composite microbial agent);

[0057] Soil conditioner No. 1: nonionic high molecular polymer prepared in Example 1;

[0058] Soil conditioner No. 2: nonionic high molecular polymer prepared in Example 2;

[0059] Soil conditioner No. 3: nonionic high molecular polymer prepared in Example 3;

[0060] Soil conditioner No. 4: nonionic high molecular polymer prepared in Comparative Example 1;

[0061] Soil conditioner No. 5: nonionic high molecular polymer prepared in Comparative Example 2;

[0062] Soil conditioner No. 6: nonionic high molecular polymer prepared in Comparative Example 3;

[0063] Soil conditioner No. 7: nonionic high molecular polymer prepared in Comparative Example 4;

[0064] Soil conditioner No. 8: commercially available non-ionic polyacrylamide.

[0065] Each soil conditioner was fully mixed with the test soil and potted. Each pot was filled with 15 kg of test soil and 1.8 g of soil conditioner. A blank group was set up without adding soil conditioner. After potting, water was poured until the soil reached saturated water holding capacity, and sowed (corn, Zhengdan 958), 10 seeds per pot. After sowing, the surface was covered with about 0.5 cm of dry soil, and the humidity was maintained at 70% of the field water holding capacity. The seedlings were fixed at the three-leaf stage, 3 plants per pot, and the aboveground weight and root weight of the corn (drying weighing method), soil pH value and salt content (conductivity method) were measured at the harvest time. The results are as follows:

[0066] Soil conditioner number Soil pH Salt content (g / kg) Plant height (cm) Single bud fresh weight (g / plant) 0 8.33 5.63 172 239 1 7.55 2.17 231 310 2 7.57 2.36 225 293 3 7.53 2.39 220 295 4 7.70 3.38 192 256 5 7.62 3.19 207 277 6 7.82 5.11 181 244 7 7.68 3.42 202 263 8 7.93 5.08 182 247 Blank group 9.36 5.89 162 224

[0067] The results show that after adding the polyacrylamide derivatives prepared in Examples 1-3, the salt and alkali reduction effects are improved, the corn yield is increased, and it is worse than ordinary commercially available non-ionic polyacrylamide. In Comparative Examples 1 and 3, no siloxane monomers are introduced, and the soil remediation effect and yield increase effect are not as good as those in Examples 1-3. The results of Comparative Examples 2 and 4 show that the polymer of the present invention is more targeted for saline-alkali soil remediation and has a better remediation effect by introducing specific types of monomers and polymerizing under appropriate ratios. Among them, Example 1 is the best example. Further, the non-ionic high molecular polymer of Example 1 is fixedly used, and different addition amounts and formulas are adjusted, and the remediation effect is measured according to the above method.

[0068] Soil conditioner No. 1: 60 parts of desulfurized gypsum, 50 parts of furfural residue, 20 parts of diatomaceous earth, 5 parts of boric acid, 1 part of composite microbial agent and 5 parts of non-ionic high molecular polymer;

[0069] Soil conditioner No. 9: 40 parts of desulfurized gypsum, 30 parts of furfural slag, 10 parts of diatomaceous earth, 2 parts of boric acid, 0.5 parts of composite microbial agent and 8 parts of non-ionic high molecular polymer;

[0070] Soil conditioner No. 10: 100 parts of desulfurized gypsum, 60 parts of furfural residue, 30 parts of diatomaceous earth, 8 parts of boric acid, 2 parts of composite microbial agent and 3 parts of non-ionic high molecular polymer;

[0071] Soil conditioner No. 11: 60 parts of desulfurized gypsum, 70 parts of furfural slag, 5 parts of boric acid, 1 part of composite microbial agent and 5 parts of non-ionic high polymer.

[0072] The results are as follows:

[0073] Soil conditioner number Soil pH Salt content (g / kg) Plant height (cm) Single bud fresh weight (g / plant) 1 7.55 2.17 231 310 9 7.54 2.25 224 301 10 7.63 2.48 217 287 11 7.59 2.31 220 299

[0074] The results show that the more the nonionic high molecular polymer prepared in Example 1 is compounded in the formula in the proportion of soil conditioner No. 1, the better the repair effect. In addition, adding an appropriate amount of diatomaceous earth can improve the improvement effect of the soil conditioner.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A saline-alkali soil conditioner, characterized in that: include: Desulfurized gypsum, furfural slag, diatomaceous earth, boric acid, composite microbial agents and non-ionic high polymers; The preparation method of the nonionic high molecular polymer comprises the following steps: Mix water, acrylamide, fatty alcohol polyoxyethylene ether and siloxane, adjust the temperature to 20-35°C, add redox initiator composition, carry out polymerization reaction for 2-5h, raise the temperature to 50-75°C and keep the temperature for 0.5-2h, and dry the product to obtain the non-ionic macromolecule.

2. The saline-alkali soil conditioner according to claim 1, characterized in that The saline-alkali soil conditioner comprises, by weight: 40-100 parts of desulfurized gypsum, 30-60 parts of furfural slag, 10-30 parts of diatomaceous earth, 2-8 parts of boric acid, 0.5-2 parts of composite microbial agent and 3-8 parts of non-ionic high molecular polymer.

3. The saline-alkali soil conditioner according to claim 1, characterized in that Based on 150g of water, the added amount of acrylamide is 20-50g, the added amount of fatty alcohol polyoxyethylene ether is 1-10g, and the added amount of siloxane is 0.3-5g.

4. The saline-alkali soil conditioner according to claim 1, characterized in that Based on 150g of water, the added amount of acrylamide is 25g, the added amount of fatty alcohol polyoxyethylene ether is 5g, and the added amount of siloxane is 3g.

5. The saline-alkali soil conditioner according to claim 1, characterized in that Based on 150 g of water, the amount of the redox initiator composition added is 0.05-0.2 g.

6. The saline-alkali soil conditioner according to claim 1, characterized in that The redox initiating composition includes ammonium persulfate and potassium bisulfite.

7. The saline-alkali soil conditioner according to claim 6, characterized in that The mass ratio of the ammonium persulfate to potassium bisulfite is 1-5:1-5.

8. The saline-alkali soil conditioner according to claim 1, characterized in that The polymerization reaction time is 3 hours; after the polymerization reaction, the temperature is raised to 62° C. and then kept warm for 1 hour.

9. The saline-alkali soil conditioner according to claim 1, characterized in that The molecular weight of the non-ionic high molecular polymer is 900,000-1.2 million.

10. A method for soil remediation, characterized in that: The method comprises the step of applying the saline-alkali soil conditioner according to any one of claims 1 to 9 to the soil.

Images