An efficient desalination method for coastal saline-alkali beach soil

Abstract

The present invention relates to the field of soil improvement, and specifically relates to an efficient desalination method for coastal saline-alkali beach soil, which includes the following steps: uniformly mixing a soil conditioner into the soil and performing deep rotary tillage; the soil conditioner includes an inorganic carrier and a fermentation product, and the mass ratio of the inorganic carrier to the fermentation product is 1:3; the inorganic carrier includes gypsum, diatomaceous earth and modified sepiolite, which are mixed in a mass ratio of 8:2:3, calcined for 1 h, pulverized, and then prepared; the preparation method of the modified sepiolite powder is: after pulverizing sepiolite, adding a sodium hexametaphosphate solution for hydrothermal reaction to obtain modified sepiolite; the method of the present invention uses a soil conditioner to improve the soil structure, rapidly reduce the soil salinity, and accelerate the cultivation of soil organic matter and the formation of aggregates.

Description

Technical Field

[0001] The present invention relates to the field of soil improvement, and particularly to an efficient desalination method for coastal saline-alkali tidal flat soil. Background Art

[0002] The salinization of land is an ecological problem worldwide. At present, the degree of land salinization globally shows an obvious upward trend, and the salinization of soil has become an important limiting factor for the sustainable development of world agriculture. In order to ensure the food production safety of our country, improve the ecological environment, and realize the sustainable utilization of resources, it is extremely urgent to accelerate the development of saline-alkali land improvement technologies.

[0003] Tidal flats are important reserve land resources in China, characterized by large area, concentrated distribution, good location conditions, and great potential for comprehensive development of agriculture, animal husbandry, and fishery. Tidal flats are an important land resource and space resource, and also an important base for developing agricultural production. The reclaimed tidal flats are all saline-alkali lands, with poor soil fertility, lack of organic matter, and single species of microorganisms, making it difficult for general crops to grow and the natural improvement process to be slow. Therefore, there is an urgent need for an efficient desalination method for coastal saline-alkali tidal flat soil to solve the problems of serious soil salinization and land shortage in coastal areas.

[0004] From a comprehensive analysis of aspects such as improvement effect and economic benefits of agricultural production, biological improvement measures are relatively economical and effective ways. Some halophytes have the function of absorbing salt ions in the soil, thereby reducing the salt content in the soil, and at the same time have the functions of increasing the nutrient content in the soil and improving the soil compaction condition; the covering effect of plants on the ground reduces ground evaporation and hinders the accumulation of soil surface salt, thereby achieving the purpose of soil improvement and salt reduction. The biological measure of planting salt-tolerant plants to improve coastal tidal flat saline-alkali land is not only beneficial to the protection of the coastal ecological environment but also beneficial to improving the agricultural production efficiency in coastal areas and the utilization rate of agricultural land in coastal areas. However, currently, the methods for improving tidal flat soil usually have high improvement costs, complex processes, or cause new pollution. Therefore, there is an urgent need for a reasonable and effective method for improving tidal flat soil. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide an efficient desalination method for coastal saline-alkali tidal flat soil.

[0006] To achieve the purpose of the present invention, the technical solution adopted by the present invention is:

[0007] An efficient desalination method for coastal saline-alkali tidal flat soil, comprising the following steps: uniformly mixing a soil conditioner into the soil and performing deep rotary tillage; the soil conditioner includes an inorganic carrier and a fermentation product, and the mass ratio of the inorganic carrier to the fermentation product is 1:3;

[0008] The inorganic carrier includes gypsum, diatomite and modified sepiolite, which are prepared by mixing gypsum, diatomite and modified sepiolite in a mass ratio of 8:2:3, calcining for 1 h, and then pulverizing; the preparation method of the modified sepiolite powder is: after pulverizing sepiolite, adding a sodium hexametaphosphate solution for hydrothermal reaction to obtain modified sepiolite;

[0009] The preparation method of the fermentation product is: mixing Suaeda salsa, Sesbania cannabina and microbial inoculum evenly, adding clear water, stacking the mixture in a greenhouse at 45 °C for fermentation for 20 days, then transferring it to an environment at 40 °C, evenly sprinkling quicklime every 3 days and turning it over once, and ending the fermentation after 30 days to obtain the fermentation product.

[0010] Further, the application amount of the soil conditioner is 20 kg per mu.

[0011] Further, the rotary tillage depth is 35 - 40 cm.

[0012] Further, the microbial inoculum includes Bacillus subtilis, Phanerochaete chrysosporium and Bacillus mucilaginosus.

[0013] Further, the ratio of Bacillus subtilis, Phanerochaete chrysosporium and Bacillus mucilaginosus is 5:2:3.

[0014] Further, in the preparation of the fermentation product, first dry and pulverize Suaeda salsa and Sesbania cannabina to 5 - 10 cm.

[0015] Further, the fermentation product uses the following raw materials in parts by mass: 40 parts of Suaeda salsa, 15 parts of Sesbania cannabina, 1 part of microbial inoculum, 100 parts of clear water, and 0.002 parts of quicklime.

[0016] Further, the calcination temperature is 1100 - 1200 °C.

[0017] Further, the mass ratio of the gypsum, diatomite and modified sepiolite is 8:2:3.

[0018] Further, the temperature of the hydrothermal reaction is 150 - 200 °C.

[0019] An efficient desalination method for coastal saline-alkali beach soil includes the following steps: evenly mixing a soil conditioner in the soil, performing deep rotary tillage, and the rotary tillage depth is 35 - 40 cm, and the application amount of the soil conditioner is 20 kg per mu.

[0020] The soil conditioner includes an inorganic carrier and a fermentation product, and the mass ratio of the inorganic carrier to the fermentation product is 1:3.

[0021] The inorganic carrier includes gypsum, diatomite and modified sepiolite, which are prepared by mixing gypsum, diatomite and modified sepiolite in a mass ratio of 8:2:3, calcining at 1100-1200 °C for 1 h, and then pulverizing;

[0022] The preparation method of the modified sepiolite powder is as follows: after pulverizing sepiolite, adding a sodium hexametaphosphate solution, and carrying out a hydrothermal reaction at 150-200 °C to obtain modified sepiolite.

[0023] The preparation method of the fermentation product is as follows: after drying and pulverizing Suaeda salsa and Sesbania cannabina to 5-10 cm, mixing them according to the following weight ratio: 40 parts of Suaeda salsa, 15 parts of Sesbania cannabina, and 1 part of microbial inoculant. After mixing evenly, adding 100 parts of clear water, stacking the mixture in a greenhouse at 45 °C for fermentation for 20 days, then transferring it to an environment at 40 °C, evenly sprinkling 0.002 parts of quicklime every 3 days and turning it over once, and ending the fermentation after 30 days to obtain the fermentation product. The microbial inoculant includes Bacillus subtilis, Phanerochaete chrysosporium and Bacillus mucilaginosus, and the ratio of Bacillus subtilis, Phanerochaete chrysosporium and Bacillus mucilaginosus is 5:2:3.

[0024] Beneficial effects

[0025] In view of the shortage of fresh water resources in the base, and combining with the problems of heavy salt content, rapid salt return, poor structure and low organic matter content in the coastal saline-alkali land, the present invention provides an efficient desalination method for coastal saline-alkali soil, which uses a soil conditioner to improve the soil structure, rapidly reduce the soil salt content, and accelerate the cultivation of soil organic matter and the formation of aggregates.

[0026] The present invention combines the fermentation product and the inorganic carrier. The inorganic carrier has rich pores with different pore sizes and contains rich silicon, calcium and magnesium elements, which can not only adjust the soil pH value, but also provide medium element nutrients required by plants. In addition, the inorganic carrier described in the present invention can effectively adsorb the microbial cells in the fermentation product. The fermentation product is rich in microorganisms and organic matter. The combination of the inorganic carrier and the fermentation product is not only beneficial to soil desalination, but also unexpectedly found that the soil improvement method of the present invention can also play a role in passivating heavy metals.

[0027] By modifying sepiolite, its adsorption performance can be enhanced, making sepiolite have better dispersibility, viscosity and thermal stability, and being able to better achieve the effects of desalination and heavy metal adsorption. In addition, the method described in the present invention also has a certain effect of passivating heavy metals, reducing the absorption and accumulation of heavy metals by plants in the soil, and promoting the transformation of heavy metal elements in the soil from a form with higher activity to a form with lower activity, thereby reducing the bioavailability and mobility of heavy metals. Description of the drawings

[0028] Figure 1The following is a comparison chart of the soil before and after improvement using the method described in the present invention (the upper figure is before improvement, and the lower figure is after improvement). Detailed implementation manners

[0029] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will describe in conjunction with the embodiments of the present invention.

[0030] Embodiment 1

[0031] An efficient desalination method for coastal saline-alkali beach soil, comprising the following steps: uniformly mixing a soil conditioner in the soil and performing deep rotary tillage, with the rotary tillage depth being 40 cm, and the application amount of the soil conditioner being 20 kg per mu.

[0032] The soil conditioner includes an inorganic carrier and a fermentation product, and the mass ratio of the inorganic carrier to the fermentation product is 1:3.

[0033] The inorganic carrier includes gypsum, diatomite and modified sepiolite, which are mixed in a mass ratio of 8:2:3, calcined at 1200 °C for 1 h, and then pulverized to obtain;

[0034] The preparation method of the modified sepiolite powder is: after pulverizing sepiolite, adding a sodium hexametaphosphate solution and performing a hydrothermal reaction at 180 °C to obtain modified sepiolite.

[0035] The preparation method of the fermentation product is: after drying and pulverizing Suaeda salsa and Sesbania cannabina to 5 cm, mixing them according to the following weight ratio: 40 parts of Suaeda salsa, 15 parts of Sesbania cannabina, and 1 part of microbial inoculant are mixed evenly, then adding 100 parts of clear water, stacking the mixture in a greenhouse at 45 °C for fermentation for 20 days, transferring it to an environment at 40 °C, evenly sprinkling 0.002 parts of quicklime every 3 days and turning it over once, and ending the fermentation after 30 days to obtain the fermentation product. The microbial inoculant includes Bacillus subtilis, Phanerochaete chrysosporium and Bacillus mucilaginosus, and the ratio of Bacillus subtilis, Phanerochaete chrysosporium and Bacillus mucilaginosus is 5:2:3.

[0036] Comparative example 1

[0037] An efficient desalination method for coastal saline-alkali beach soil, the difference between this embodiment and Embodiment 1 is: no inorganic carrier is added.

[0038] Comparative example 2

[0039] An efficient desalination method for coastal saline-alkali beach soil, the difference between this embodiment and Embodiment 1 is: no fermentation product is added.

[0040] Comparative example 3

[0041] An efficient desalination method for coastal saline-alkali tidal flat soil. The difference between this example and Example 1 is that gypsum is not used as the inorganic carrier.

[0042] Comparative Example 4

[0043] An efficient desalination method for coastal saline-alkali tidal flat soil. The difference between this example and Example 1 is that diatomite is not used as the inorganic carrier.

[0044] Comparative Example 5

[0045] An efficient desalination method for coastal saline-alkali tidal flat soil. The difference between this example and Example 1 is that modified sepiolite is not used as the inorganic carrier.

[0046] Comparative Example 6

[0047] An efficient desalination method for coastal saline-alkali tidal flat soil. The difference between this example and Example 1 is that ordinary sepiolite without modification is used as the inorganic carrier.

[0048] Comparative Example 7

[0049] An efficient desalination method for coastal saline-alkali tidal flat soil. The difference between this example and Example 1 is that deep rotary tillage is not carried out, and only the soil conditioner is spread on the soil surface, and the dosage is the same as that in Example 1.

[0050] Comparative Example 8

[0051] An efficient desalination method for coastal saline-alkali tidal flat soil. The difference between this example and Example 1 is that the inorganic carrier does not go through the calcination step.

[0052] Example 2

[0053] The selected tidal flat is located in the Tiaozini Reclamation Area of Dongtai, Jiangsu. It belongs to the silty coast of the accretion type, with a coastal facies landform, flat terrain, and a subtropical humid monsoon climate with distinct seasons. The precipitation is mainly concentrated in June - August. Soil samples were collected from the original landform of the project area and soil quality analysis was carried out. The soil structure is extremely poor, the soil pH is 8.7, the organic matter content is 2.31 g / kg, and the salt content in the 0 - 20 cm plough layer soil is 1.05%; the soil nutrients are lacking, and the high soil salinity and low soil organic matter content are the main obstacles to crop production in this tidal flat area. At the same time, there is also a certain degree of Cd pollution problem.

[0054] Table 1 Soil aggregate content

[0055]

[0056]

[0057] Table 2 Soil physical and chemical property indexes

[0058]

[0059] The plots with similar soil conditions in the above-mentioned tidal flat areas were divided into 10 groups, with 3 replicates set in each group. One of the groups was selected as the control without any treatment, and the other 9 groups were respectively used to improve the soil by the methods of Example 1 and Comparative Examples 1 - 8. After 2 months, the salt content in the soil was counted, and the Cd content in the Suaeda salsa plants growing in the above-mentioned plots was detected. The results are as follows:

[0060]

[0061] The above results show that the desalination method described in the present invention can achieve good desalination effects. By crushing the straw, through steps such as microbial fermentation and adding inorganic carriers, and then deep rotary tillage and returning to the field, the soil structure is improved, the soil capillary is cut off, a salt - inhibiting layer is constructed, effectively inhibiting the surface accumulation of soil salts, effectively reducing the soil salt content in the plough layer, improving the physical and chemical properties of the soil, and increasing the soil organic matter and nutrient content. The inorganic carrier described in the present invention can effectively adsorb the microbial cells in the fermentation products. The fermentation products are rich in microorganisms and organic matter. The combination of the inorganic carrier and the fermentation products is not only beneficial to soil desalination, but also unexpectedly found that the soil improvement method of the present invention can also play a role in passivating heavy metals. Through the modification treatment of sepiolite, its adsorption performance can be enhanced, making sepiolite have better dispersibility, viscosity and thermal stability, and being able to better achieve the effects of desalination and heavy metal adsorption.

[0062] In addition, the method described in the present invention also has a certain effect of passivating heavy metals, reducing the absorption and accumulation of soil heavy metals by plants, promoting the transformation of heavy metal elements in the soil from a higher - activity form to a lower - activity form, thereby reducing the bioavailability and mobility of heavy metals.

[0063] Example 3

[0064] Select the same area as described in Example 2, and divide the plots with similar soil conditions into 5 groups, with 3 replicates set in each group. Each group was respectively used to improve the soil by the method described in Example 1. The dosages of the inorganic carrier and the fermentation products were the same as those in Example 1, and the only difference was that the raw materials for preparing the fermentation products were different. After 2 months, the salt content in the soil was counted, and the Cd content in the Suaeda salsa plants growing in the above - mentioned plots was detected. The results are as follows:

[0065]

[0066] The above data show that the fermentation products used in the present invention can achieve good technical effects.

[0067] Example 4

[0068] Select the same area as described in Example 2, and divide the plots with similar soil conditions into 5 groups. Each group is set with 3 replicate plots. The soil in each group is improved by the method described in Example 1, with the only difference being the application rate of the soil conditioner. After 2 months, the salt content in the soil is counted, and the Cd content in the Suaeda salsa plants growing in the above plots is detected. The results are as follows:

[0069]

[0070]

[0071] The above data show that when the application rate of the soil conditioner is 20 kg per mu, the balance between cost and technical effect can be achieved.

Claims

1. An efficient desalination method for coastal saline-alkali beach soil, characterized in that, Uniformly mix the soil conditioner into the soil and conduct deep rotary tillage with a tillage depth of 35 - 40 cm. The application rate of the soil conditioner is 20 kg per mu. The soil conditioner includes an inorganic carrier and a fermentation product, and the mass ratio of the inorganic carrier to the fermentation product is 1:

3. The inorganic carrier includes gypsum, diatomite, and modified sepiolite, which are mixed in a mass ratio of 8:2:3, calcined at 1200 °C for 1 h, and then pulverized to obtain. The preparation method of the modified sepiolite is as follows: After pulverizing sepiolite, add a sodium hexametaphosphate solution and conduct hydrothermal reaction at 180 °C to obtain modified sepiolite. The preparation method of the fermentation product is as follows: After drying and pulverizing Suaeda salsa and Sesbania cannabina to 5 - 10 cm, mix them according to the following proportion by weight: 40 parts of Suaeda salsa, 15 parts of Sesbania cannabina, and 1 part of microbial inoculum. After mixing evenly, add 100 parts of clear water, stack the mixture in a greenhouse at 45 °C for fermentation for 20 days, then transfer it to an environment at 40 °C, evenly sprinkle 0.002 parts of quicklime every 3 days and turn it over once. After 30 days, the fermentation ends to obtain the fermentation product. The microbial inoculum includes Bacillus subtilis, Phanerochaete chrysosporium, and Bacillus mucilaginosus in a ratio of 5:2:3.

Images