Saline alkali soil eluting agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of saline-alkali soil improvement, and particularly discloses a saline-alkali soil eluting agent and a preparation method and application thereof. The saline alkali soil eluting agent provided by the invention is prepared from the following components in parts by weight: 50 to 60 parts of maleic anhydride-itaconic acid copolymer, 10 to 20 parts of levulinic acid, 5 to 10 parts of calcium nitrate, 1 to 5 parts of surfactant, 0.1 to 2 parts of dispersing agent, 0.1 to 2 parts of penetrating agent and 10 to 20 parts of water, the weight-average molecular weight of the maleic anhydride-itaconic acid copolymer is 500 to 5000Da; the invention further provides application of the saline-alkali soil eluting agent in saline-alkali soil. The saline-alkali soil eluting agent provided by the invention not only can effectively solve the structural problem of saline-alkali soil, but also can greatly improve the eluting efficiency, reduce the consumption and waste of water resources, reduce the pH of the saline-alkali soil, improve the soil structure and realize comprehensive treatment of the saline-alkali soil.

Description

Technical Field

[0001] The present application relates to the technical field of saline-alkali land improvement, and in particular to a saline-alkali soil eluting agent and a preparation method and application thereof. Background Art

[0002] The management of saline-alkali land is a crucial topic in agriculture and environmental science. With global climate change and inappropriate land use, the area of ​​saline-alkali land is expanding, severely impacting crop yields and ecological balance. Currently, researchers and agricultural producers are actively seeking effective saline-alkali land improvement methods to restore soil fertility and improve crop productivity. However, despite the availability of a variety of technologies and products for saline-alkali land management, numerous challenges remain, including high costs, complex operations, and environmental pollution.

[0003] In order to deal with the above problems, the commonly used methods in the prior art include physical methods, chemical methods, biological methods and other means. Among them, the physical method mainly includes deep loosening and deep tillage, drainage and salt washing, etc., which aim to reduce salt accumulation by changing the soil structure and enhancing water mobility. The chemical method usually adopts the application of lime, gypsum or other chemical reagents to adjust the soil pH and dissolve salt. In addition, the biological method is to improve soil quality by planting salt-tolerant plants or introducing microorganisms. Although these methods can alleviate the salinization problem to a certain extent, they still face many difficulties in practical applications. For example: the traditional method needs to control the water-to-soil ratio of saline-alkali soil to about 1.5-3:1, which consumes a lot of water resources; in addition, saline-alkali soil also has problems such as low efficiency of salt washing and salt discharge during hydrophobic leaching.

[0004] Therefore, how to solve the problems of large water resource consumption and low leaching efficiency in the existing saline-alkali land management has become the key to the current saline-alkali land management. Summary of the Invention

[0005] In order to overcome the problems of large water resource consumption and low leaching efficiency in the existing saline-alkali land management, the present application provides a saline-alkali soil eluting agent and its preparation method and application.

[0006] In the first aspect, the saline-alkali soil eluting agent provided by this application adopts the following technical solution: A saline-alkali soil eluting agent comprising the following components in parts by weight: 50-60 parts of maleic anhydride-itaconic acid copolymer, 10-20 parts of levulinic acid, 5-10 parts of calcium nitrate, 1-5 parts of a surfactant, 0.1-2 parts of a dispersant, 0.1-2 parts of a penetrant, and 10-20 parts of water; The weight average molecular weight of the maleic anhydride-itaconic acid copolymer is 500-5000 Da.

[0007] This application uses maleic anhydride-itaconic acid copolymer, levulinic acid and calcium nitrate to prepare a saline-alkali soil eluting agent. On the one hand, the saline-alkali soil eluting agent can break up salt crystals, allowing salts such as calcium, magnesium, and sodium to return to ions; on the other hand, through ion analysis and displacement, it can replace the metal cations adsorbed in the colloid and can be eluted quickly and to the maximum extent. Specifically: the maleic anhydride-itaconic acid copolymer contains multiple polycarboxylic acid groups. During the elution process, these groups will ionize to form negatively charged molecular chains, which can not only decompose the Ca2+ adsorbed by the soil colloid, but also remove the metal cations adsorbed by the soil colloid. 2+ Mg 2+ 、Na + It can also release the calcium salts (such as CaCO3, CaSO4, calcium phosphate) fixed in the soil and turn them into free Ca 2+ , thereby increasing the Ca content in the soil 2+ concentration, which can more effectively replace the adsorbed Na + , improving leaching efficiency. In addition, maleic anhydride-itaconic acid copolymer hydrolyzes to generate anions, which will be enriched near the calcium salt and magnesium salt crystals in saline-alkali soils to form a double electric layer, thereby hindering the aggregation of metal cations on the metal surface and effectively preventing the formation of large crystals, making it easier for salt ions to be discharged with the water flow, further enhancing leaching efficiency. Levulinic acid and maleic anhydride-itaconic acid copolymer can dissociate H in the soil solution. + , has a strong buffering capacity, can reduce the alkalinity of the soil to a certain extent; at the same time, these two components are also biodegradable and will not cause secondary pollution to the soil environment, ensuring the sustainability and environmental protection of the treatment. Surfactants can not only improve the dispersion performance of the eluent, but also synergize with calcium nitrate to further increase the Ca content in the soil solution. 2+ concentration, thereby enhancing Na + The dispersant and penetrant can effectively solve the problem of soil water repellency, so that water can be evenly distributed in the soil in a "matrix" flow manner, ensuring that water fully infiltrates the soil both vertically and horizontally, greatly improving the leaching effect and reducing the waste of water resources. In summary, the saline-alkali soil leaching agent provided by this application reduces the Na + and anion groups, which can effectively solve the structural problems of saline-alkali soil and provide a new solution for the comprehensive management of saline-alkali land.

[0008] Optionally, the maleic anhydride-itaconic acid copolymer is a mixture of a maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 900-1200 Da and a maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 3000-5000 Da.

[0009] Optionally, the weight ratio of the maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 900-1200 Da to the maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 3000-5000 Da is 1:(0.3-0.5).

[0010] In some embodiments, the weight ratio of the maleic anhydride-itaconic acid copolymer having a weight average molecular weight of 900-1200 Da to the maleic anhydride-itaconic acid copolymer having a weight average molecular weight of 3000-5000 Da can be 1:(0.2-0.3), 1:(0.2-0.4), 1:(0.2-0.5), 1:(0.2-0.6), 1:(0.3-0.4), 1:(0.3-0.5), 1:(0.3-0.6), 1:(0.4-0.5), 1:(0.4-0.6) or 1:(0.5-0.6).

[0011] In a specific embodiment, the weight ratio of the maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 900-1200 Da to the maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 3000-5000 Da can also be 1:0.2, 1:0.3, 1:0.4, 1:0.5 or 1:0.6.

[0012] Optionally, the penetrant is selected from one or more of block polyether Y-1, AEO-9, rhamnolipid, saponin and sodium dodecylbenzenesulfonate.

[0013] Optionally, the penetrant is a mixture of block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate.

[0014] In the present application, a mixture of block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate is used as a penetrant.

[0015] Among them, block polyether Y-1 and sodium dodecylbenzene sulfonate have a good enhanced penetration effect, which can help the components in the eluent to penetrate into the soil and effectively remove saline-alkali components. On the one hand, rhamnolipid has good wettability and permeability, which can promote the eluent to better disperse and penetrate into the deep layer of the soil; on the other hand, it can also ionize Rh- and H+ under alkaline conditions, and neutralize with OH- in alkaline soil, thereby improving the alkaline environment of the soil. In summary, this application uses the above-mentioned several penetrants in combination, which can synergistically promote the penetration of effective ingredients in the eluent from many aspects, reduce the surface tension of the aqueous solution in saline-alkali soil, reduce the aqueous solution infiltration angle, increase surface ductility, and make the salt in the saline-alkali soil flow more fully with water, thereby removing the salt ions in the saline-alkali soil by eluting and reducing the soil pH.

[0016] Optionally, the penetrant is a block polyether Y-1, rhamnolipid, saponin, and sodium dodecylbenzenesulfonate in a weight ratio of (2-4):1:(1-3):(0.5-1.5). In some embodiments, the weight ratio of the block polyether Y-1, rhamnolipid, saponin, and sodium dodecylbenzenesulfonate can be (2-3):1:2:1, (3-4):1:2:1, 3:1:(1-2):1, 3:1:(2-3):1, 3:1:2:(0.5-1), 3:1:2:(1-1.5).

[0017] In a specific embodiment, the weight ratio of the block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate can also be 2:1:2:1, 3:1:2:1, 4:1:2:1, 3:1:1:1, 3:1:3:1, 3:1:2:0.5 or 3:1:2:1.5.

[0018] Optionally, the surfactant is calcium lignin sulfonate; and the dispersant is NNO.

[0019] In a second aspect, the present application provides an application of a saline-alkali soil eluting agent in saline-alkali soil.

[0020] In a third aspect, the present application provides a method for treating saline-alkali land soil, comprising the following steps: first, diluting the saline-alkali soil eluent by 8-12 times, then draining the eluent dilution to the irrigation water outlet, and draining it together with the irrigation water to the saline-alkali land; the saline-alkali soil eluent is used in an amount of 40-50 kg / mu / time in the saline-alkali land soil; the irrigation water is irrigated in an amount of 80-100 m 3 / mu.

[0021] Optionally, during the irrigation process, equipment such as rotary tillage machinery is used to stir the soil.

[0022] In summary, this application has the following beneficial effects: 1. This application uses maleic anhydride-itaconic acid copolymer, levulinic acid and calcium nitrate to prepare a saline-alkali soil eluent. On the one hand, this saline-alkali soil eluent can break up salt crystals in saline-alkali soil, allowing salts such as calcium, magnesium and sodium to return to ions. On the other hand, it can decompose and replace metal cations in the soil, and then discharge them with water, ultimately achieving the improvement and treatment of saline-alkali soil.

[0023] 2. The present application prepares a saline-alkali soil eluent by adjusting the molecular weight of a maleic anhydride-itaconic acid copolymer and further using a mixture of a maleic anhydride-itaconic acid copolymer with a weight-average molecular weight of 900-1200Da and a maleic anhydride-itaconic acid copolymer with a weight-average molecular weight of 3000-5000Da. The obtained saline-alkali soil eluent has a better elution effect on metal ions in saline-alkali soil, a higher salt removal efficiency, and can effectively reduce the pH of saline-alkali soil.

[0024] 3. In the saline-alkali soil elution agent provided in this application, the use of a penetrant causes the water flow in the saline-alkali soil to flow in a "matrix" manner, that is, the water will flow evenly and diffusely in all directions, and can flow evenly and to the maximum extent in the soil both vertically and horizontally, thereby improving the saline-alkali elution efficiency and saving elution water.

[0025] 4. The present application further uses block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate in a weight ratio of (2-4):1:(1-3):(0.5-1.5) as eluents, which can further improve the elution effect of the saline-alkali soil eluent on saline-alkali soil salt ions, thereby significantly reducing the total salt content in the saline-alkali soil. The total salt content of the soil at 0-20 cm can be reduced to below 1.00%, and the total salt content of the soil at 20-40 cm can be reduced to below 1.50%. DETAILED DESCRIPTION

[0026] The present application provides a saline-alkali soil eluting agent, comprising the following components in parts by weight: 50-60 parts of a maleic anhydride-itaconic acid copolymer, 10-20 parts of levulinic acid, 5-10 parts of calcium nitrate, 1-5 parts of a surfactant, 0.1-2 parts of a dispersant, 0.1-2 parts of a penetrant, and 10-20 parts of water; wherein the weight-average molecular weight of the maleic anhydride-itaconic acid copolymer is 500-5000 Da; further, the maleic anhydride-itaconic acid copolymer is a mixture of a maleic anhydride-itaconic acid copolymer having a weight-average molecular weight of 900-1200 Da and a maleic anhydride-itaconic acid copolymer having a weight-average molecular weight of 3000-5000 Da; further, the weight ratio of the maleic anhydride-itaconic acid copolymer having a weight-average molecular weight of 900-1200 Da to the maleic anhydride-itaconic acid copolymer having a weight-average molecular weight of 3000-5000 Da is 1:(0.3-0.5). The penetrant is selected from one or more of block polyether Y-1, AEO-9, rhamnolipid, saponin, and sodium dodecylbenzenesulfonate. Furthermore, the penetrant is block polyether Y-1, rhamnolipid, saponin, and sodium dodecylbenzenesulfonate in a weight ratio of (2-4):1:(1-3):(0.5-1.5).

[0027] The preparation method of the saline-alkali soil eluent comprises the following steps: adding deionized water to a reactor, heating the reactor to 40-50°C, and setting the stirring speed to 60-70 rpm; then sequentially adding maleic anhydride-itaconic acid copolymer and levulinic acid, stirring for 5-10 minutes, then adding calcium nitrate and calcium lignin sulfonate, stirring for 10-15 minutes, then adding a dispersant and a penetrant, continuing stirring for 10-15 minutes, stopping stirring and heating, and cooling to obtain the saline-alkali soil eluent.

[0028] The present application provides a saline-alkali land soil improvement and management method, comprising the following steps: firstly, diluting a saline-alkali soil eluent by 8-12 times, then draining the eluent dilution to an irrigation water outlet, and draining the eluent dilution to the saline-alkali land together with the irrigation water, and using a rotary tillage machine and other equipment to stir the soil during the irrigation process; the saline-alkali soil eluent is used in an amount of 40-50 kg / mu / time in the saline-alkali land soil; the irrigation water is used in an amount of 80-100 m3 / time; 3 / mu.

[0029] In the present application, maleic anhydride-itaconic acid copolymer was purchased from Shandong Xinrunfeng Chemical Co., Ltd.; the CAS number of levulinic acid is 123-76-2; calcium nitrate; block polyether Y-1 was purchased from Tai'an Yuanhengli Agrochemical Co., Ltd.; AEO-9 was purchased from Shandong Xinquansheng Chemical Technology Co., Ltd.; rhamnolipid was purchased from Merck; saponin was a hydrosaponin extract purchased from Shaanxi Bolin Biotechnology Co., Ltd.; the CAS number of calcium lignin sulfonate is 8061-52-7; the dispersant is NNO dispersant; the raw materials, reagents, solvents, etc. used in this application can all be obtained commercially.

[0030] The present application is further described in detail below with reference to embodiments and performance testing.

[0031] Examples 1-10 Examples 1-10 each provide a saline-alkali soil eluting agent.

[0032] The difference between the above embodiments is that the weight average molecular weight and ratio of the maleic anhydride-itaconic acid copolymer are shown in Table 1 below.

[0033] The preparation method of the saline-alkali soil eluent provided in Examples 1-10 comprises the following steps: adding 15 g of deionized water to a reactor, heating the reaction mixture to 45° C., and setting the stirring speed to 65 rpm; then sequentially adding 60 g of maleic anhydride-itaconic acid copolymer and 15 g of levulinic acid, stirring for 5 minutes, followed by adding 8 g of calcium nitrate and 3 g of calcium lignin sulfonate, stirring for 10 minutes, and then adding 1 g of an NNO dispersant and 1 g of a penetrant (block polyether Y-1, rhamnolipid, and sodium dodecylbenzenesulfonate in a weight ratio of 4:1:1) and continuing stirring for 15 minutes. Then, stopping stirring and heating, and cooling the reaction mixture to obtain the saline-alkali soil eluent.

[0034] Table 1 Weight average molecular weight and ratio of maleic anhydride-itaconic acid copolymer in Examples 1-10 Example Weight average molecular weight and ratio of maleic anhydride-itaconic acid copolymer 1 900-1200Da 2 1500-2500Da 3 3000-5000Da 4 The weight ratio of 900-1200Da to 3000-5000Da is 1:0.2 5 The weight ratio of 900-1200Da to 3000-5000Da is 1:0.3 6 The weight ratio of 900-1200Da to 3000-5000Da is 1:0.4 7 The weight ratio of 900-1200Da to 3000-5000Da is 1:0.5 8 The weight ratio of 900-1200Da to 3000-5000Da is 1:0.6 9 The weight ratio of 900-1200Da to 1500-2500Da is 1:0.4 10 The weight ratio of 1500-2500Da to 3000-5000Da is 1:0.4 Examples 11-19 Examples 11-19 each provide a saline-alkali soil eluting agent.

[0035] The difference between the above embodiment and embodiment 6 is: the type and ratio of the penetrant, as shown in Table 2 below.

[0036] Table 2 Types and ratios of penetrants in Example 6 and Examples 11-17 Comparative Example 1 Comparative Example 1 provides a saline-alkali soil eluting agent.

[0037] The difference between the comparative example and Example 6 is that the weight average molecular weight of the maleic anhydride-itaconic acid copolymer is 6000-8000 Da.

[0038] Comparative Example 2 Comparative Example 2 provides a saline-alkali soil eluting agent.

[0039] The difference between the comparative example and Example 6 is that the added amount of maleic anhydride-itaconic acid copolymer is 30 g, the added amount of levulinic acid is 30 g, and the added amount of calcium nitrate is 20 g.

[0040] Performance testing The saline-alkali soil eluting agents obtained in Examples 1-19 and Comparative Examples 1-2 were used to conduct soil column eluting experiments to test their performance. The results are shown in Table 3 below.

[0041] (1) The soil used in this experiment is sandy soil in coastal tidal flat saline-alkali land. The basic physical and chemical properties of the soil are shown in Table 3.

[0042] Table 3 Physical and chemical properties of tidal flat saline-alkali soil (2) A soil column elution experiment was conducted using the saline-alkali soil elution agents obtained in Examples 1-19 and Comparative Examples 1-2 and clean water according to the following method. After elution once, the total salt content and pH change of the saline-alkali soil were detected. The specific process is as follows: ① Soil column device: Made of PVC pipe, 15 cm in diameter, set at a height of 50 cm. Lay nylon mesh and double-layer absorbent gauze on the bottom and fix them tightly to ensure that the eluent can only flow out from the bottom. ② Fill in layers: Each soil column is filled with 10kg of saline-alkali soil, and compacted once every 10cm of soil layer according to the natural bulk density until the soil layer reaches a height of 40cm. Place a piece of filter paper on the surface to ensure that the eluent is evenly distributed; ③ Solution elution: dilute 5g of eluent 2000 times to 10kg of eluent, i.e., the water-soil ratio is 1:1. Continue eluting until the eluent is used up and leave it for 2 days. ④ Soil sampling and testing: Soil from the surface to the 20 cm soil layer and the 30-40 cm soil layer were collected for soil total salinity and pH testing. The results are shown in Table 4 below. Table 4 Total salt and pH of different soil layers after saline-alkali soil leaching According to the test results in Table 4, after leaching the saline-alkali soil with the saline-alkali soil eluting agent provided in Example 1-19, the total salt content of the soil at 0-20 cm can be reduced to 0.69-1.97% (≤2.0%), and the pH is 7.40-7.60; the total salt content at 20-40 cm can be reduced to 1.24-2.39% (≤2.5%), and the pH is 7.46-7.69; while after leaching the saline-alkali soil with the saline-alkali soil eluting agent provided in Comparative Example 1-2, the total salt content of the soil at 0-20 cm is only reduced to 2.15-2.36% (>2.0%), and the pH is 7.65-7.68; the total salt content at 20-40 cm is only reduced to 2.76-2.86% (>2.5%), and the pH is 7.74-7.81. Therefore, it is explained that the present application uses maleic anhydride-itaconic acid copolymer, levulinic acid and calcium nitrate to prepare a saline-alkali soil eluent, and the molecular weight of the maleic anhydride-itaconic acid copolymer is controlled within the range of 500-5000 Da, and the addition amount of each component is controlled within the following range: 50-60 parts of maleic anhydride-itaconic acid copolymer, 10-20 parts of levulinic acid, 5-10 parts of calcium nitrate, 1-5 parts of surfactant, 0.1-2 parts of dispersant, 0.1-2 parts of penetrant and 10-20 parts of water. The obtained saline-alkali soil eluent can resolve salt ions from soil colloids, thereby achieving effective removal of salt in saline-alkali soil and a significant reduction in pH.

[0043] The test results of Examples 1-10 show that Example 1-3 uses a maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 900-1200Da, 1500-2500Da or 3000-5000Da to prepare a saline-alkali soil elution agent. After eluting the saline-alkali soil, the total salt content of the soil at 0-20cm is 1.91-1.97%, the pH is 7.57-7.60, and the total salt content of the soil at 20-40cm is 2.14-2.39%, and the pH is 7.64-7.69; Examples 9-10 use a 900-1200Da maleic anhydride-itaconic acid copolymer and a 1500-2500Da maleic anhydride-itaconic acid copolymer with a weight ratio of 1:0.4 or a 1500-2500Da and 3000-5000Da with a weight ratio of 1:0.4 to prepare a saline-alkali soil elution agent, which has a pH of 7.57-7.60. After leaching of saline-alkali soil, the total salt content of the soil at 0-20 cm was 1.84-1.92%, the pH was 7.57-7.58, and the total salt content of the soil at 20-40 cm was 2.11-2.23%, the pH was 7.63-7.67; while in Examples 4-8, maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 900-1200 Da and maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 3000-5000 Da were used. A saline-alkali soil eluting agent is prepared by using a mixture of maleic anhydride-itaconic acid copolymers. After eluting the saline-alkali soil, the total salt content of the soil at 0-20 cm is 1.12-1.57% (≤1.60%), the pH is 7.45-7.54 (≤7.55), and the total salt content of the soil at 20-40 cm is 1.81-1.98% (≤2.00%), and the pH is 7.7.56-7.60 (≤7.60). Therefore, it is explained that the present application uses a mixture of maleic anhydride-itaconic acid copolymers with a weight-average molecular weight of 900-1200 Da and a maleic anhydride-itaconic acid copolymer with a weight-average molecular weight of 3000-5000 Da to prepare a saline-alkali soil eluting agent. The obtained saline-alkali soil eluting agent has better decomposition and elution effects on metal ions in saline-alkali soil, higher metal ion removal efficiency, and lower soil pH.

[0044] The test results of Example 6 and Examples 11-19 show that Example 6 uses block polyether Y-1, rhamnolipid and sodium dodecylbenzenesulfonate in a weight ratio of 4:1:1 as a penetration enhancer. After the obtained saline-alkali soil eluting agent is used to elute the saline-alkali soil, the total salt content of the soil at 0-20 cm is 1.12%, the pH is 7.45, and the total salt content of the soil at 20-40 cm is 1.81%, and the pH is 7.56; Examples 18-19 use block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate in a weight ratio of 1:1:1:1 or block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate in a weight ratio of 1:4:1:1 as a penetration enhancer. After the obtained saline-alkali soil eluting agent is used to elute the saline-alkali soil, the total salt content of the soil at 0-20 cm is 1.12%, the pH is 7.45, and the total salt content of the soil at 20-40 cm is 1.81%, and the pH is 7.56. The total salt content of the soil at 0-20 cm was 1.03-1.16%, the pH was 7.44-7.45, the total salt content at 20-40 cm was 1.73-1.78%, and the pH was 7.53-7.57; while in Examples 11-17, block polyether Y-1, rhamnolipid, saponin, and sodium dodecylbenzenesulfonate in a weight ratio of (2-4):1:(1-3):(0.5-1.5) were used as eluents. After the obtained saline-alkali soil eluent was used to elute the saline-alkali soil, the total salt content of the soil at 0-20 cm was 0.69-0.92% (≤1.00%), the pH was 7.40-7.43 (≤7.43), the total salt content at 20-40 cm was 1.24-1.50% (≤1.50%), and the pH was 7.46-7.50 (≤7.50). Therefore, it is shown that the present application further adopts block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate in a weight ratio of (2-4): 1: (1-3): (0.5-1.5) as an eluent, which can further improve the elution effect of the saline-alkali soil eluent on the salt of the saline-alkali soil, so that the total salt content in the saline-alkali soil is significantly reduced, and the total salt content of the soil of 0-20 cm can be reduced to below 1.00%, and the total salt content of 20-40 cm can be reduced to below 1.50%.

[0045] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A saline-alkali soil eluting agent, characterized in that: The invention comprises the following components in parts by weight: 50-60 parts of maleic anhydride-itaconic acid copolymer, 10-20 parts of levulinic acid, 5-10 parts of calcium nitrate, 1-5 parts of surfactant, 0.1-2 parts of dispersant, 0.1-2 parts of penetrant and 10-20 parts of water; The weight average molecular weight of the maleic anhydride-itaconic acid copolymer is 500-5000 Da.

2. The saline-alkali soil eluting agent according to claim 1, characterized in that The maleic anhydride-itaconic acid copolymer is a mixture of a maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 900-1200 Da and a maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 3000-5000 Da.

3. The saline-alkali soil eluting agent according to claim 2, characterized in that The weight ratio of the maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 900-1200 Da to the maleic anhydride-itaconic acid copolymer with a weight average molecular weight of 3000-5000 Da is 1:(0.3-0.5).

4. The saline-alkali soil eluting agent according to claim 1, characterized in that The penetrant is selected from one or more of block polyether Y-1, AEO-9, rhamnolipid, saponin and sodium dodecylbenzenesulfonate.

5. The saline-alkali soil eluting agent according to claim 4, characterized in that The penetrant is block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate in a weight ratio of (2-4):1:(1-3):(0.5-1.5).

6. The saline-alkali soil eluting agent according to claim 4, characterized in that The weight ratio of the block polyether Y-1, rhamnolipid, saponin and sodium dodecylbenzenesulfonate is 3:1:2:

1.

7. The saline-alkali soil eluting agent according to any one of claims 1 to 6, characterized in that The surfactant is calcium lignin sulfonate; the dispersant is NNO.

8. Use of the saline-alkali soil eluting agent according to any one of claims 1 to 7 in saline-alkali soil.

9. A method for treating saline-alkali soil, characterized in that: The following steps are involved: First, dilute the saline-alkali soil eluent by 8-12 times, then drain the eluent dilution to the irrigation water outlet and drain it to the saline-alkali land together with the irrigation water; the saline-alkali soil eluent is used in an amount of 40-50 kg / mu / time; the irrigation water is used in an amount of 80-100 m 3 / mu.

10. The saline-alkali soil treatment method according to claim 9, characterized in that: During the irrigation process, equipment such as rotary tillage machinery is used to stir the soil.

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