CN115647023A - Method for compositely repairing cadmium-polluted rice field soil - Google Patents
Method for compositely repairing cadmium-polluted rice field soil Download PDFInfo
- Publication number
- CN115647023A CN115647023A CN202211546251.0A CN202211546251A CN115647023A CN 115647023 A CN115647023 A CN 115647023A CN 202211546251 A CN202211546251 A CN 202211546251A CN 115647023 A CN115647023 A CN 115647023A
- Authority
- CN
- China
- Prior art keywords
- rice
- cadmium
- soil
- compositely
- early
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Cultivation Of Plants (AREA)
Abstract
The invention provides a method for compositely repairing cadmium-polluted rice field soil, which organically combines a milk vetch pressure-turning technology, a magnesium-calcium-aluminum hydrotalcite broadcasting technology and a technology of preparing biochar from early and late rice straws and returning the biochar to the field, wherein the biochar is applied to passivate cadmium in soil, and the application of the magnesium-calcium-aluminum hydrotalcite further reduces the bioavailability of cadmium in the soil, reduces the absorption of cadmium by rice and reduces the cadmium content in brown rice; the turning and pressing of the milk vetch and the rice stubble can not only improve the organic matter content in the soil, increase the alkaline matter of the soil and reduce the effective cadmium content in the soil, but also reduce or offset the adverse effects of the magnesium, calcium, aluminum and hydrotalcite on the physicochemical property and the microbial community of the soil. The method not only reduces the cadmium content of the brown rice of the rice and ensures the safe production of the rice, but also has the function of improving the physical and chemical properties of soil, microbial communities and fertility, thereby increasing the rice yield, finding a cheap and practical regulation and control technology for repairing the medium-light cadmium-polluted rice field and reducing the cadmium content of the brown rice, and having good application prospect.
Description
Technical Field
The invention belongs to the technical field of farmland pollution treatment, and particularly relates to a method for compositely repairing rice fields polluted by medium and light cadmium and reducing the cadmium content of brown rice.
Background
Cadmium (Cd) is one of five toxic heavy metal elements (Cd, as, cr, pb and Hg), and the Japanese famous "pain disease" event is caused by the influence of long-term eating of high-cadmium rice on the normal metabolism of calcium, which leads to severe osteoporosis and finally death. When the paddy field soil is seriously polluted by cadmium, the free cadmium in the soil is absorbed and utilized by rice and is accumulated in the rice, and the rice with excessive cadmium accumulation seriously threatens the health of human beings, so that the remediation of the cadmium-polluted farmland is urgent.
In the past, researches on remediation of heavy metal pollution of soil mostly focus on physical and chemical methods for heavy metal adsorption and fixation, for example, the heavy metal content of soil is reduced to a certain extent by methods such as soil dressing, soil replacement, chemical leaching and the like, but the problems of large engineering quantity, high remediation cost or potential safety hazard exist, for example, groundwater pollution or damage to a soil ecosystem caused by chemical leaching is possible, and the cost is high. The use of lime is also a method for remediating cadmium-contaminated farmland, but changes in external environmental conditions can lead to reactivation and release of stable heavy metals in the soil, and studies indicate that excessive lime application can lead to soil hardening and even crop death.
Therefore, how to find a low-cost and easy-to-implement restoration technology has important and practical significance for restoring cadmium-polluted farmlands and realizing the standard production of rice.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for compositely repairing cadmium-polluted paddy field soil.
In order to achieve the purpose, the invention provides the following technical scheme:
a method for compositely repairing cadmium-polluted paddy field soil comprises the following steps:
s1, harvesting late rice, reserving 30-50 cm high rice stubble, making the whole or part of harvested late rice straw into charcoal and returning the charcoal to the field, sowing milk vetch, and ditching by manpower or a ditching machine in sunny days;
s2, spreading magnesium-calcium-aluminum hydrotalcite in soil before early rice seedling transplantation, and then turning and pressing milk vetch;
s3, transplanting early rice seedlings, harvesting early rice in harvest season, and preparing early rice straws into biochar to be returned to the field
The hydrotalcite belongs to Layered Double Hydroxides (LDHs), is a supermolecular structure anionic layered clay composite material assembled by a main body laminate with positive charges and interlayer anions through the interaction of non-covalent bonds, and has a chemical composition general formula of [ M 2+ 1-x M 3+ x (OH) 2 ] x+ (A n- x/n ) ·mH 2 O, wherein M 2+ 、M 3+ Represent a divalent and a trivalent metal cation, respectively, the subscript x indicating the content of the metal element varies, A n- Represents an anion; magnesium calcium aluminum hydrotalcite is hydrotalcite with cations including Mg, ca and Al.
Preferably, in the magnesium calcium aluminum hydrotalcite, al is 2 O 3 The mass fractions of CaO and MgO are respectively 10-25%, 30-55% and 1.2-5%.
Preferably, in the step S1, the seeding rate of the milk vetch is 1.0-2.0 kg/mu.
Preferably, in the step S2, the application amount of the magnesium-calcium-aluminum hydrotalcite is 100-200 kg/mu.
Preferably, the biochar returning is carried out 1 to 3 days before the early rice seedling transplanting in the step S1.
Preferably, the milk vetch may be sown before or after harvesting late rice.
Preferably, the broadcasting of the magnesium calcium aluminum hydrotalcite is carried out 7 to 10 days before the early rice seedlings are transplanted.
Preferably, the early rice and the late rice are harvested mechanically.
Preferably, the returning of the early rice straws to the field is carried out 1 to 3 days before the transplanting of the late rice seedlings or 7 to 15 days after the transplanting in the step S3.
Compared with the prior art, the invention has the following beneficial effects:
the invention innovatively adopts the astragalus sinicus turning and pressing technology and the magnesium-calcium-aluminum hydrotalcite broadcasting technology,The technology for preparing biochar from late rice straws and returning the biochar to the field is combined into a technical mode for repairing the soil of the rice field with medium and light cadmium pollution and reducing the cadmium content of the brown rice of the rice. The method comprises the steps of reserving 30-50 cm high rice stubbles after late rice is harvested, preparing late rice straws into biochar and returning the biochar to the field, sowing milk vetch, then spreading magnesium-calcium-aluminum hydrotalcite before early rice is planted, and turning over and pressing the milk vetch and the high rice stubbles. After the biochar is applied to soil, the adsorption capacity to heavy metals is strong, and oxygen-containing functional groups on the surface of the biochar can also be mixed with Cd 2+ A complex is formed, so that cadmium in soil is passivated, the cadmium in the soil can be quickly anchored in a crystal lattice of a hyperstable mineralizer by applying the magnesium-calcium-aluminum hydrotalcite through isomorphous substitution or dissolution-reconstruction, the magnesium-cadmium-aluminum hydrotalcite (MgCdAl-LDH) with a more stable structure is formed by mineralization, the cadmium is fixed in the crystal lattice and is very stable and difficult to dissociate, and therefore, the effect of further reducing the biological effectiveness of the cadmium in the soil is achieved, the absorption of the cadmium by rice is reduced, and the content of the cadmium in brown rice is reduced; the overturning and pressing of the milk vetch and the rice stubble can not only improve the organic matter content in the soil, but also increase the alkaline substances of the soil and reduce the effective cadmium content of the soil, and the milk vetch not only can overcome the secondary pollution possibly caused by applying an artificially synthesized chelating agent and the like, but also is a good natural organic fertilizer; meanwhile, by adopting the measure of returning milk vetch and straw biochar to the field, the adverse effects of a passivating material (magnesium calcium aluminum hydrotalcite) on the physical and chemical properties of soil and the microbial community can be reduced or offset, the bioavailability of cadmium in the soil of the cadmium-polluted rice field is reduced, the absorption of cadmium by rice is reduced, the cadmium content of brown rice of rice is reduced, the safety production of rice is realized, the effects of improving the physical and chemical properties of soil, the microbial community and the fertility are achieved, the yield of rice is increased, a cheap and practical regulation and control technology is found for repairing the rice field polluted by medium and light cadmium and reducing the cadmium content of brown rice, and the application prospect is good.
Detailed Description
In order to facilitate an understanding of the invention, the invention will now be described more fully and in detail with reference to the accompanying description and preferred embodiments, but the scope of the invention is not limited to the specific embodiments described below.
Example 1
In 2021 to 2022, 9.5 mu of cadmium-polluted farmland and 4 mu of land are selected in spring cross river towns in Heshan area of Yiyang city, hunan province, the area of each land is more than 1.5 mu, wherein one half of each land adopts the technology of the invention, and the other half adopts a conventional management mode as a control.
Harvesting late rice 10 months and 12 days 2021, reserving 50cm rice stubble when harvesting, preparing the harvesting part into biochar, and returning the biochar to the field 1 day before transplanting early rice seedlings; sowing 2 kg/mu of astragalus sinicus seeds in the test area in 20 days after 10 months, and ditching with manpower or a ditching machine in sunny days;
the control area is winter-free. In the test area, 200 kg/mu of magnesium calcium aluminum hydrotalcite is manually applied in 2022 in 12 days in 4 months and 12 months 2 O 3 CaO and MgO respectively account for 16.95 percent, 45.14 percent and 1.41 percent in mass fraction, and then the astragalus sinicus is turned over and pressed. Early rice seedlings are transplanted in 19 days in 4 months, and the early rice variety is Xiang early long shaped No. 45. Harvesting 7 months and 7 days of early rice, removing straw stalks to prepare biochar, and returning the biochar to the field 1 day before the late rice seedlings are transplanted; transplanting late rice in 14 days in 7 months, wherein the late rice is Nongxiang No. 42, and harvesting the late rice in 26 days in 10 months.
The test field is located in a cadmium-polluted rice field in a certain cadmium-polluted rice field in the Heshan region of spring cross river town of Yiyang city, hunan province, the pH of the soil before the test is 5.20, and the total Cd content is 0.530 mg/kg. The cadmium content of the early rice brown rice in the test area is 0.161 mg/kg, the cadmium content of the brown rice in the control area is 0.639 mg/kg, and the cadmium content of the early rice brown rice in the test area is reduced by 74.8% compared with that of the control area. The cadmium content of the brown rice of the late rice in the test area is 0.095 mg/kg, the cadmium content of the brown rice of the late rice in the comparison area is 0.483 mg/kg, and the cadmium content of the brown rice in the test area is reduced by 80.3 percent compared with that of the brown rice in the comparison area.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (9)
1. A method for compositely repairing cadmium-polluted paddy field soil is characterized by comprising the following steps:
s1, harvesting late rice, reserving rice stubble with the height of 30-50 cm, making the whole or partial harvested late rice straw into charcoal to return to the field, sowing milk vetch, and ditching with manpower or a ditching machine in sunny days after sowing;
s2, spreading magnesium-calcium-aluminum hydrotalcite in soil before early rice seedling transplantation, and then turning and pressing milk vetch;
and S3, transplanting early rice seedlings, harvesting early rice in the harvest season, and preparing the early rice straw into charcoal for returning to the field.
2. The method for compositely remediating cadmium-contaminated paddy soil as recited in claim 1, wherein Al is contained in the Mg-Ca-Al-hydrotalcite 2 O 3 CaO and MgO in the amount of 10-25 wt%, 30-55 wt% and 1.2-5 wt%.
3. The method for compositely remediating cadmium-contaminated paddy field soil as recited in claim 1, wherein in the step S1, the seeding rate of the milk vetch is 1.0 to 2.0 kg/mu.
4. The method for compositely remediating cadmium-contaminated paddy soil as recited in claim 1, wherein in the step S2, the application amount of the mg-ca-al-hydrotalcite is 100 to 200 kg/mu.
5. The method for combined remediation of cadmium-contaminated paddy soil as claimed in claim 1, wherein the biochar application to field is performed 1 to 3 days before the early rice seedling transplantation in step S1.
6. The method for compositely remediating cadmium-contaminated paddy soil as recited in claim 1, wherein said milk vetch is sown before or after harvesting late rice.
7. The method for compositely remediating cadmium-contaminated paddy soil as recited in claim 1, wherein the early season rice and the late season rice are harvested mechanically.
8. The method for compositely remediating cadmium-contaminated paddy soil as recited in claim 1, wherein said broadcasting of the mg-ca-al-hydrotalcite is performed 7 to 10 days before transplanting the seedlings of the early season rice.
9. The method for composite remediation of cadmium contaminated paddy field soil as claimed in claim 1, wherein in step S3, the early rice straw returning is performed 1 to 3 days before the late rice seedling is transplanted or 7 to 15 days after the late rice seedling is transplanted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211546251.0A CN115647023A (en) | 2022-12-05 | 2022-12-05 | Method for compositely repairing cadmium-polluted rice field soil |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211546251.0A CN115647023A (en) | 2022-12-05 | 2022-12-05 | Method for compositely repairing cadmium-polluted rice field soil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115647023A true CN115647023A (en) | 2023-01-31 |
Family
ID=85019188
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211546251.0A Pending CN115647023A (en) | 2022-12-05 | 2022-12-05 | Method for compositely repairing cadmium-polluted rice field soil |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115647023A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117413738A (en) * | 2023-12-19 | 2024-01-19 | 中国农业科学院农业资源与农业区划研究所 | Safety production method of rice for cadmium-polluted rice field soil |
-
2022
- 2022-12-05 CN CN202211546251.0A patent/CN115647023A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117413738A (en) * | 2023-12-19 | 2024-01-19 | 中国农业科学院农业资源与农业区划研究所 | Safety production method of rice for cadmium-polluted rice field soil |
| CN117413738B (en) * | 2023-12-19 | 2024-03-22 | 中国农业科学院农业资源与农业区划研究所 | Safety production method of rice for cadmium-polluted rice field soil |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107446589B (en) | Acid soil cadmium passivator and application thereof | |
| CN103766182B (en) | A kind of rice cultivating method of effective reduction paddy cadmium content | |
| AU2020103286A4 (en) | Combined passivator for reducing cadmium content in paddy field soil and its application method | |
| CN109530417B (en) | Method for performing crop rotation, repairing and production of rape-medium rice in cadmium-polluted soil | |
| Dagar et al. | Performance of some under‐explored crops under saline irrigation in a semiarid climate in Northwest India | |
| CN107446588A (en) | Humic acid type acidic soil conditioner and preparation method and application | |
| CN100345475C (en) | Quick planting and establishing method for alkaline land vegetation | |
| CN106278692A (en) | A kind of acidic soil conditioner and preparation method thereof | |
| CN109548595A (en) | A kind of semilate rice-wheat crop rotation method in cadmium slight pollution soil | |
| CN111408621B (en) | Cadmium contaminated soil composite microorganism repairing agent and technical method for repairing while producing | |
| CN108752138A (en) | The complex repairation agent administered for heavy metals in farmland cadmium pollution and restorative procedure and application | |
| RU2316923C1 (en) | Soil detoxication method | |
| CN111357591A (en) | Safe utilization method of cadmium-arsenic composite polluted rice field | |
| CN115647023A (en) | Method for compositely repairing cadmium-polluted rice field soil | |
| CN107523306A (en) | Reduce the chemical inactivators of heavy metal and its application in soil | |
| CN105176538A (en) | Acid soil conditioner containing chitosan oligosaccharide and application | |
| CN112974492A (en) | Strongly acidic high-heavy-metal-content mining wasteland combined ecological restoration method | |
| CN104718835A (en) | Method for assisting in ecological restoration of tailings through alfalfa green manure and planting alfalfa | |
| CN108485671B (en) | Cadmium-polluted soil conditioner, preparation method thereof and cadmium-polluted soil conditioning method | |
| CN107141122A (en) | Organic fertilizer suitable for acid soil and preparation method thereof | |
| KR100667005B1 (en) | Method for tree-planting cutting-side with species diversity restoration | |
| CN1218909C (en) | Anti salt and alkali paddy rice seedling strengthening fertilizer | |
| Dagar | Opportunities for alternate land uses in salty and water scarcity areas | |
| CN109913233B (en) | Rice field soil heavy metal passivation modifier | |
| KR101201346B1 (en) | A Botanical Composition for The Surface of Slope |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |