NL2032519A

NL2032519A - Method for Preparing Soil Conditioner by Utilizing Plateau Lake Sediments

Info

Publication number: NL2032519A
Application number: NL2032519A
Authority: NL
Inventors: Zhang Jiachun; Mu Guiting; Liu Yingying; Zhang Zhenming; Wu Xianliang; Luo Wenmin; Zeng Xianping; He Hongzao
Original assignee: Univ Guizhou
Priority date: 2021-10-26
Filing date: 2022-07-16
Publication date: 2023-05-19
Also published as: CN113845387A; NL2032519B1

Abstract

The invention relates to the technical field of lake sediment reuse, in particular to a method for preparing a soil conditioner by using plateau lake sediments. Specifically, the method comprises the following steps: uniformly mixing plateau lake sediments, straw powder, livestock manure and active carbon, heating and pre - treating by microwave to obtain a mixture, adding microbial agent, composting and fermenting, and drying to obtain a fermentation product; the fermentation product and heavy metal chelating agent are evenly mixed to obtain the soil conditioner. The plateau lake sediments are fermented by microorganisms to prepare soil conditioners, and the nutrients and organic matter in the lake sediments were fully utilized to realize waste utilization.

Description

Method for Preparing Soil Conditioner by Utilizing Plateau Lake Sediments

TECHNICAL FIELD

The invention relates to the technical field of lake sediment reuse, in particular to a method for preparing a soil conditioner by using plateau lake sediments.

BACKGROUND

Lake sediments, as the main carrier of surface and atmospheric sediments, accumulate a lot of nutrients, organic matter and other substances, and are important reservoirs of various nutrients. Regular cleaning of the sediments at the bottom of the lake can prevent the reverse release of the material components in the lake sediments, avoid the eutrophication of the water body and the secondary release of pollutants, restore the ecosystem of the water body and improve the water quality.

For clearing lake sediments at the bottom of the lake, the existing disposal methods are generally simple stacking and natural drying. On the one hand, it requires a large number of stacking sites, and the natural drying usually lasts for a long time, which often results in a great waste of resources in the case of limited land area. On the other hand, the stacking process may also cause secondary pollution to the stacking area, so finding a reasonable treatment method for lake sediments has always been a difficult problem in the lake bottom dredging project.

SUMMARY

Based on the above, the present invention provides a method for preparing soil conditioner by using plateau lake sediments. The plateau lake sediments were fermented by microorganisms to prepare soil conditioners, and the nutrients and organic matter in the lake sediments were fully utilized to realize waste utilization.

One of the technical schemes of the invention is a method for preparing a soil conditioner by using plateau lake sediments.

Comprises the following steps: (1) plateau lake sediments, straw powder, livestock manure and active carbon are evenly mixed, then pre - treated by microwave heating to obtain a mixture, and microbial agents are added for composting fermentation treatment and then dried to obtain fermentation products; (2) uniformly mixing fermentation products and heavy metal chelating agents to obtain the soil conditioner.

Furthermore, in the step (1), the mixing mass ratio of plateau lake sediments, straw powder, livestock manure and activated carbon is (5-10): (3-5): (3-8): (2-5).

Furthermore, in the step (1), the microwave heating pre - treatment specifically includes the microwave power of 500 - 1,000 W, temperature 100 - 200°C, time 10 - 30min.

Furthermore, in the step (1), after microwave heating pre - treatment, before adding microbial agent, the mixture is dehydrated until the moisture content is 50 - 75%.

Further, in the step (1), the microbial agent comprises 10 - 20 parts of Bacillus subtilis, 10 - 20 parts of Bacillus laterosporus, 5 - 10 parts of photosynthetic bacteria, 3 - 5 parts of nitrifying bacteria and 3 - 5 parts of nitrogen - fixing bacteria.

Further, in the step (1), the mixing mass ratio of the microbial agent and the mixture is (0.1 - 1) : {100 - 300); the composting fermentation is aerobic composting fermentation, the fermentation temperature is 30 - 45°C, and the fermentation time is 3 - 5 days.

Further, in the step (1), the drying is freeze drying.

Furthermore, in the step (2), the mass ratio of fermentation product to heavy metal chelating agent is 10 : (0.5- 1).

The second technical scheme of the invention is the soil conditioner prepared by the method for preparing the soil conditioner by using plateau lake sediments.

Compared with the prior art, the invention has the following beneficial effects: plateau lake sediments are rich in carbon, nitrogen, phosphorus and trace elements, which are essential nutrients for plant growth. Therefore, using plateau lake sediments to prepare soil conditioners can not only improve the nutrients in the soil to a great extent, but also realize waste utilization and solve the technical problems of environmental pollution caused by lake sediments accumulation in the prior art. However, because the carbon, nitrogen and phosphorus resources in the sediments of plateau lakes are mostly in the form of macromolecular organic matter, which can be directly used as soil conditioners, there is a problem that they can't be well absorbed and utilized by plants, and microbial degradation is a good solution to this problem. By composting fermentation with microbial treatment, the utilization rate of nutrients in the sediments of plateau lakes can be improved, and beneficial soil bacteria can be introduced into products to further improve the improvement effect of soil conditioners.

Plateau lake sediments and livestock manure contain a large number of refractory organic components and pathogenic bacteria, and direct microbial fermentation affects the survival rate of microbial fermented strains, and the fermentation process takes a long time, so the effect is not good. The invention pre-treats the refractory organic substances in plateau lake sediments, straw powder and livestock manure by microwave heating treatment, which destroys the original connection structure and promotes their rapid decomposition in the subsequent fermentation process. At the same time, the microwave process also plays a role in killing bacteria, ensuring the survival rate of strains in the fermentation process, thus improving the microbial treatment.

Straw powder has strong adsorption property, and after being mixed with plateau lake sediments and livestock manure, the three can be quickly mixed by adsorption property. At the same time, in the process of microwave, organic polar molecules generated by decomposition of cellulose, hemicellulose and other components in straw and moisture absorbed in straw can play a role in absorbing microwave and improve the efficiency of microwave pre - treatment. A proper amount of activated carbon is also added into the microwave mixture, which has strong adsorption and microwave absorption. The purpose of pre - decomposing plateau lake sediments and livestock manure in a short time can be achieved by adsorbing organic matters in plateau lake sediments and livestock manure and combining with its own strong microwave absorption, thus further improving microwave efficiency.

The fermentation product after microbial fermentation is mixed with heavy metal chelating agent to prepare soil conditioner, which can fix possible residual heavy metals in plateau lake sediments, livestock manure and soil to prevent heavy metal ions from polluting the environment.

The soil modify of that invention takes lake sediment as the main material component, which is similar to the soil, and can be mixed and used according to the nutrient condition of the soil in any proportion; At the same time, after microwave pre - treatment and fermentation treatment, its organic components are degraded but not completely decomposed, so that the slow release effect is achieved and the soil environment would not be eutrophic due to poor plant absorption effect. The soil conditioner of the invention contains abundant silicon, iron, calcium, sodium and trace elements, which is beneficial to soil growth. The added straw powder and activated carbon have certain adsorption properties, which can achieve the effects of nitrogen fixation and phosphorus fixation when used.

DESCRIPTION OF THE INVENTION

Now, various exemplary embodiments of the present invention will be described in detail.

This detailed description should not be taken as a limitation of the present invention, but should be understood as a more detailed description of some aspects, characteristics and embodiments of the present invention.

It should be understood that the terms mentioned in the present invention are only used to describe specific embodiments, and are not used to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed.

Every smaller range between any stated value or the intermediate value within the stated range and any other stated value or the intermediate value within the stated range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

Unless otherwise stated, all technical and scientific terms used herein have the same meanings commonly understood by those of ordinary skill in the field to which this invention relates. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials related to the documents. In case of conflict with any incorporated documents, the contents of this specification shall prevail.

Without departing from the scope or spirit of the present invention, it is obvious to those skilled in the art that many modifications and changes can be made to the specific embodiments of the present specification. Other embodiments obtained from the description of the present invention will be obvious to the skilled person. The description and embodiment of that invention are only exemplary.

As used in this paper, the terms "comprising", "including", "having" and "containing" are all open terms, meaning including but not limited to.

Example 1

According to the mass ratio of 10 :3:3:2, plateau lake sediments, straw powder (corn straw is dried to a moisture content below 10% and crushed by a 100 - mesh sieve), livestock manure (pig manure) and activated carbon are evenly mixed and placed in a microwave environment.

After microwave treatment at 1000W and 150°C for 20 minutes, the mixture is dehydrated to a moisture content of 50%.

The mixture and microbial agents (20 parts of Bacillus subtilis, 15 parts of Bacillus laterosporus, 10 parts of photosynthetic bacteria, 5 parts of nitrifying bacteria, 5 parts of nitrogen - fixing bacteria, and the total amount of strain is 10 cfu/g) are mixed according to the mass ratio of 200 :0.5, and then the fermentation products are obtained by aerobic composting fermentation at 35 - 45°C for 4 days.

After the fermentation product is freeze - dried in low temperature and vacuum, the heavy metal chelating agent {commercially available) is mixed according to the mass ratio of 10 :0.5 to obtain the soil conditioner.

Example 2

According to the mass ratio of 5:5:8:5, plateau lake sediments and straw powder (corn straw is dried to a moisture content of less than 10% and crushed by a 100 - mesh sieve), livestock manure (pig manure) and activated carbon are evenly mixed, placed in a microwave environment, treated by microwave at 500W and 200°C for 10 minutes, and then dehydrated to a moisture content of 75% to obtain a mixture.

The mixture and microbial agents (10 parts of Bacillus subtilis, 20 parts of Bacillus laterosporus, 5 parts of photosynthetic bacteria, 3 parts of nitrifying bacteria, 3 parts of nitrogen - fixing bacteria, and the total amount of strain is 10 cfu/g) are mixed according to the mass ratio of 300 : 1, and then the fermentation products are obtained by aerobic composting fermentation, with the fermentation temperature of 35 - 45°C and the fermentation time of 3 days.

After the fermentation product is freeze - dried in low temperature and vacuum, heavy metal chelating agents (dithiocarbamate derivatives on the market) are mixed according to the mass ratio of 10 : 1 to obtain the soil conditioner. 5 Example 3

The mixture and microbial agent (20 parts of Bacillus subtilis, 15 parts of Bacillus laterosporus, 10 parts of photosynthetic bacteria, 5 parts of nitrifying bacteria, 5 parts of nitrogen - fixing bacteria, and the total strain amount of 10 cfu/g) are mixed in a mass ratio of 200 :0.5. After mixing, aerobic composting fermentation is carried out to obtain fermentation products, the fermentation temperature is 35 - 45°C, and the fermentation time is 4 days.

After the fermentation product is freeze - dried in low temperature and vacuum, the heavy metal chelating agent (commercially available) is mixed according to the mass ratio of 10 :0.5 to obtain the soil conditioner.

Example 4

According to the mass ratio of 8:4:5:4, the plateau lake sediments and straw powder (corn straw is dried until the moisture content is below 10% and crushed by a 100 - mesh sieve), livestock manure (pig manure) and activated carbon are evenly mixed, placed in a microwave environment, treated by microwave at 800W and 100°C for 30min, and then dehydrated until the moisture content is 60%, so as to obtain a mixture.

The mixture and microbial agent (15 parts of Baciflus sublilis, 15 parts of Bacillus laterosporus, 8 parts of photosynthetic bacteria, 4 parts of nitrifying bacteria, 4 parts of nitrogen - fixing bacteria, and the total amount of strain is 10 cfu/g) are mixed according to the mass ratio of 100 :0.1, and then the fermentation product is obtained by aerobic composting fermentation at 35-45°C for 5 days.

After the fermentation product is freeze - dried in low temperature and vacuum, the heavy metal chelating agent (commercially available) is mixed according to the mass ratio of 10 :0.6 to obtain the soil conditioner.

Example 5

Same as Example 1, except that the microwave heating pre - treatment process is omitted.

Example 6

Same as Example 1, except that the pre - treatment temperature of microwave heating is 220°C.

Example 7

Same as Example 1, except that the addition of straw powder is omitted.

Example 8

Same as Example 1, except that the addition of activated carbon is omitted.

Example 9

As in Example 1, the difference is that Bacillus subtilis is omitted from the microbial agent.

Example 10

As in Example 1, the difference is that Bacillus laterosporus is omitted in the microbial agent.

Example 11

As in Example 1, the difference is that photosynthetic bacteria are omitted in the microbial agent.

Example 12

As in Example 1, the difference is that nitrifying bacteria and nitrogen - fixing bacteria are omitted in microbial agent.

Effect example 1

The wheat planting fields in the same plot are selected for experimental verification. The planting fields are divided into 13 experimental groups with equal area, and a protective row with a width of two meters was set between two adjacent experimental groups. Experiment groups 1 - 12 respectively add the soil conditioner prepared in Example 1 - 12 according to the dosage of 50kg/ mu (1 mu is about 666.67 m3), and then turn over the ground (turning depth 15 - 20cm). Experiment group 13 only turns over the ground as a blank experiment. Experiment groups 1 - 13 are planted with wheat, planting density 10kg/ mu, sowing row spacing 18cm and sowing depth 3cm. The field management and harvest time of experiment groups 1 - 13 are the same. The emergence rate of wheat, the growth status of wheat at booting stage, the plant height and panicle length at harvest are counted, and the results are recorded in Table 1. After harvest, the yield is measured, and the results are recorded in Table 2.

Table 1

Treatment 10 - day Above Below Plant Panicle emergence | ground/fresh | ground/fresh height length

Experiment rate weight weight group (%) @ (9) (cm) (cm)

Table 2 group (kg) group (kg) 1 ee | 8 | 599 2 | es [ 9 | 582 3 | 609 | 10 | 589 6 | sm | 13 | 482 7 sat | — | —

From the data in Table 1 - 2, it can be concluded that the growth status and planting yield of wheat in the experiment group 1 - 4 provided with the soil conditioner of Examples 1 - 4 of the present invention have been significantly improved, indicating that it has excellent effect on soil improvement, while the experiment group 5 - 12 lacking some raw materials or strains has also improved the yield, but the effect is not as significant as that of the experiment group 1 - 4.

Effect example 2

Inductively coupled plasma (ICP) spectrometer is used to detect the concentration of heavy metals in wheat products and soil conditioners harvested from experiment groups 1 - 13, and the fixing effect of the soil improver on heavy metal ions In plateau lake sediments was investigated. See table 3 for the results.

Table 3

Treatment Cd, mg.kg - 1 Pb, mg.kg - 1 Cr, mg.kg - 1

Experiment group Wheat Soil Wheat Soil Wheat Sail conditioner conditioner conditioner 1 Not 212 Not 37.52 Not 62.21 detected detected detected 2 Not 2.15 Not 37.44 Not 62.08 detected detected detected 3 Not 2.06 Not 37.25 Not 62.35 detected detected detected 4 Not 2.16 Not 37.63 Not 62.44 detected detected detected

Not 212 Not 37.44 Not 62.73 detected detected detected

Not 2.14 Not 37.22 Not 62.12 detected detected detected 13 Not Not Not detected detected detected 5 It can be concluded from the data in Table 3 that the soil conditioner prepared by the embodiment of the invention has a good fixing effect on heavy metal ions in plateau lake sediments, and there is no situation that heavy metals are absorbed by wheat and exist in wheat products.

Effect example 3

After the wheat is harvested, the soil is collected from the planting land to detect the contents of soil organic matter, available nitrogen, available phosphorus and available potassium (the detection methods are the prior art, which will not be described here). The experimental results are shown in Table 4.

Table 4

Organic

Experiment matter N P K group (g/kg) (mg/kg) (mg/kg) (mg/kg) 135.2 131.5 132.4 133.5 106.8 6 [283 [eos [278 [1134 119.8 8 [288 [e628 [304 [1227 9 Jor2 [e45 = [317 [127.1 125.8 126.4 124.0 101.8

It can be concluded from Table 4 that the soil conditioner prepared by Examples 1 - 4 of the present invention can increase the content of organic matter, available nitrogen, available phosphorus and available potassium in the soil.

The above is only a preferred embodiment of the present invention, and it is not intended to limit the present invention. Any modification, equivalent substitution and improvement within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

CONCLUSIONS

A method for preparing soil conditioner using plateau lake sediments, comprising the steps of: (1) uniformly mixing plateau lake sediments, straw powder, animal manure and activated carbon, then pretreating by microwave heating to obtain a mixture, and adding microbial agents for composting and fermentation treatment, and then drying to obtain fermentation products; (2) mixing fermentation products and heavy metal chelating agents evenly to obtain the soil conditioner.

The method for preparing soil improver using plateau lake sediments according to claim 1, wherein in step (1) in the mixture, the mass ratio of plateau lake sediments, straw powder, animal manure and activated carbon (5-10): (3-5) : (3-8) : (2-5) amounts.

The method for preparing soil improver using sediments from plateau lakes according to claim 1, wherein in step (1) pretreating by microwave heating, a microwave power of 500-1,000 W, a temperature of 100-200°C and a time from 10 to 30 min.

The method for preparing soil improver using plateau lake sediments according to claim 1, wherein the mixture in step (1) after pretreatment by microwave heating, is dehydrated to the moisture content 50-75 before adding microbial agent % amounts.

The method of claim 1, wherein in step (1) the microbial agents comprise: 10 - 20 parts Bacillus subtilis, 10 - 20 parts Bacillus /aterosporus, 5 - 10 parts photosynthetic bacteria, 3 - 5 parts nitrifying bacteria and 3 - 5 parts nitrogen - fixing bacteria.

The method for preparing soil conditioner using plateau lake sediments according to claim 5, wherein in step (1), the mass ratio of the microbial agent and the mixture is (0.1 - 1): {100 - 300) , and the composting fermentation is aerobic composting fermentation, the fermentation temperature is 30-45°C, and the fermentation time is 3-5 days.

The method of claim 1, wherein in step (1) the drying is freeze-drying.

The method for preparing soil conditioner using plateau lake sediments according to claim 1, wherein in step (2), the mass ratio of fermentation product to heavy metal chelating agent is 10 : (0.5 - 1).

A soil conditioner prepared by the method of preparing soil conditioner using plateau lake sediments according to any one of claims 1-8.