CN-122007146-A - Method for regulating and controlling heavy metal enrichment capacity of super-accumulated plants in soil

CN122007146ACN 122007146 ACN122007146 ACN 122007146ACN-122007146-A

Abstract

The invention relates to the technical field of soil remediation, in particular to a method for regulating and controlling the heavy metal enrichment capability of super-accumulated plants in soil; the slow-release soil activator comprises an inner core, a middle retarding layer and an outer layer response layer, wherein the inner core is fiber reticular biochar loaded with citric acid, the middle retarding layer is a composite layer formed by combining sodium alginate and chitosan after calcium chloride crosslinking, the outer layer response layer comprises polyvinyl alcohol and sodium lignin sulfonate, the sustained release of the citric acid in the soil is realized through a multilayer structure, so that the heavy metal effectiveness is improved, and meanwhile, the nutrition growth stage of the plant is regulated and controlled through the paclobutrazol, so that the plant can keep higher heavy metal absorption capacity for a longer time.

Inventors

ZHOU JIAWEN
LIU HUAN
HUO JIALIN
ZHOU TONG
GAO TING
WU LONGHUA
HU PENGJIE
LI ZHU

Assignees

中国科学院南京土壤研究所

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (9)

1. The method for regulating and controlling the heavy metal enrichment capacity of the super-accumulation plant in the soil is characterized by comprising the following steps of: S1, loading contaminated soil into a pot, namely loading heavy metal contaminated soil into a pot container, and preparing a slow-release soil activator; S2, layering application of a slow-release soil activator, namely applying the slow-release soil activator into pot soil according to 0.3-1.2% of dry weight of polluted soil, uniformly mixing 60-80% of slow-release soil activator with soil within a depth range of 4-8 cm from the surface of the pot soil, applying the rest 20-40% of slow-release soil activator into an annular area which is 2-5 cm away from a plant planting center and is arranged around a pot planting position, and burying the slow-release soil activator into a soil layer which is 2-4 cm away from the surface of the soil; S3, transplanting plants and culturing potted plants, namely transplanting the plants in the pot soil after the slow-release soil activator is applied, and culturing the potted plants; S4, spraying and controlling paclobutrazol, namely, spraying paclobutrazol on plant leaves for 2-4 times 7-15 d after plant transplanting, wherein the paclobutrazol used in each spraying is paclobutrazol aqueous solution with the mass concentration of 180-220 mg/L at intervals of 6-10 d; And S5, feeding back and regulating the growth state of the plant, namely, before the subsequent spraying, regulating the spraying amount of the next paclobutrazol according to the plant height growth rate, the branch number, the chlorophyll value and/or the flower bud visible rate of the plant so as to improve the enrichment capability of the plant on heavy metals.
2. The method for controlling the heavy metal enrichment capacity of super-accumulating plants in soil according to claim 1, wherein the plants in S3 are cadmium-zinc super-accumulating plants.
3. The method for regulating and controlling the heavy metal enrichment capacity of the super-accumulation plant soil according to claim 1, wherein the potting culture in S3 comprises water management and nutrition supplementing management, and the specific method is as follows: SA1, transplanting plants into square pot containers with sides of 8-12 cm and heights of 8-15 cm, and planting 1 plant in each pot; SA2, keeping seedling reviving 3-5 days before transplanting, and keeping the water content of the pot soil at 60-70% of the field water holding capacity of the soil during seedling reviving; SA3, after seedling recovery, the water content of the pot soil is still kept at 60-70% of the field water holding capacity of the soil; SA4, after transplanting, recovering normal nutrition management for 5-10 days, wherein 0.1-0.2 g of the nitrogen fertilizer is added into every 1 kg pot soil according to the pure nitrogen.
4. The method for regulating and controlling the heavy metal enrichment capacity of super-accumulated plants in soil according to claim 1, wherein the paclobutrazol in S4 is sprayed on leaf surfaces, the spraying amount is 3-10 mL of each plant based on the condition that the front and the back of the leaf surfaces are uniformly wetted and do not drip.
5. The method for regulating and controlling the heavy metal enrichment capacity of super-accumulating plants in soil according to claim 1, wherein the method for regulating the spraying amount of next paclobutrazol in the step S5 is as follows: SB1, monitoring the growth state of plants between two adjacent spraying; SB1-1, when any one of the following conditions is satisfied, the next spraying amount of paclobutrazol is increased by 10-15% on the basis of the original plan: The plant height is more than or equal to 15% compared with the internal growth rate of 7 d after the previous measurement; The number of branches of a single plant is increased by more than or equal to 2 compared with the previous measurement; the flower buds are visible to the naked eyes, and the flower bud visibility rate is more than or equal to 10%; SB1-2, when any one of the following conditions is satisfied, the next spraying amount of paclobutrazol is reduced by 10-20% on the basis of the original plan: Chlorophyll value SPAD <32; The plant height is less than or equal to 4% of the internal growth rate of 7 d after the previous measurement; the new leaves are obviously reduced, curled or have phytotoxicity spots; SB2, when the water content of the basin soil is lower than 55% of the field water holding capacity of the soil, firstly, replenishing water to 60-65% of the field water holding capacity of the soil, and then, carrying out next paclobutrazol spraying after 12-36 h.
6. The method for controlling the heavy metal enrichment capacity of super-accumulated plant soil according to claim 1, wherein the pollutants of the heavy metal contaminated soil in S1 are cadmium and/or zinc.
7. The method for controlling the heavy metal enrichment capacity of super-accumulated plant soil according to claim 1, wherein the slow-release soil activator in S2 comprises an inner core, an intermediate retarding layer coated on the outer side of the inner core and an outer response layer coated on the outer side of the intermediate retarding layer; the inner core is fiber reticular biochar loaded with citric acid; The fiber mesh biochar is prepared from one of ramie fibers, jute fibers, sisal fibers, corn vascular bundle enrichment sections, reed fiber stems or bagasse long fiber sections through an oxygen-limited pyrolysis process; the middle blocking layer is a composite layer formed by combining sodium alginate and chitosan after being crosslinked by calcium chloride; The outer responsive layer comprises polyvinyl alcohol and sodium lignin sulfonate.
8. The method for regulating and controlling the heavy metal enrichment capacity of super-accumulating plants in soil according to claim 7, wherein the preparation method of the slow-release soil activator is as follows: SC1, cleaning, drying and cutting a plant fiber raw material into fiber sections with the length of 1.5-5 cm, and pyrolyzing for 2.0-2.5 hours at 470-520 ℃ under the condition of limiting oxygen to prepare fiber mesh biochar; Adding the fiber mesh biochar prepared in the SC1 into a citric acid aqueous solution with the mass concentration of 18-35% to carry out impregnation loading for 3-4 hours, and drying after impregnation to prepare the fiber mesh biochar loaded with citric acid; N is marked as a multiplying factor, and n is R + , the addition amount of each component in the SC2 is 100n g of fiber mesh biochar and 150-200 mL of citric acid aqueous solution; SC3, adding the fiber reticular biochar subjected to SC2 treatment into a sodium alginate solution with the mass concentration of 1.5-3.5%, soaking for 10-15 min, then placing into a calcium chloride solution with the mass concentration of 2-5% for crosslinking for 10-30 min, and then immersing into a chitosan solution with the mass concentration of 0.5-2.0% for treatment for 5-15 min to form an intermediate blocking layer; The addition amount of each component in the SC3 is 120-135 n g of fiber reticular biochar treated by the SC2, 80-150 n mL of sodium alginate solution, 100-180 n mL of calcium chloride solution and 80-150 n mL of chitosan solution; SC4, further placing the fiber reticular biochar subjected to SC3 treatment into an outer coating liquid composed of polyvinyl alcohol and sodium lignin sulfonate to be coated for 20-25 min, and drying to obtain the slow-release soil activator; the outer coating liquid consists of polyvinyl alcohol and sodium lignin sulfonate, the addition amount of the outer coating liquid is 80-160 n mL, and the mass ratio of the polyvinyl alcohol to the sodium lignin sulfonate is 4:1-5:1.
9. The method for regulating and controlling the heavy metal enrichment capacity of super-accumulated plant soil according to claim 8, wherein the particle size of the prepared slow-release soil activator is 2.0-3.5 mm.

Description

Method for regulating and controlling heavy metal enrichment capacity of super-accumulated plants in soil Technical Field The invention relates to the technical field of soil remediation, in particular to a method for regulating and controlling the heavy metal enrichment capability of super-accumulated plants in soil. Background The heavy metal pollution of soil is an outstanding environmental problem in the current agricultural ecological environment, wherein the heavy metal elements such as cadmium, zinc and the like have the characteristics of strong mobility, high biotoxicity, obvious environmental accumulation and the like, are difficult to eliminate through a natural process once entering a soil system, and can be absorbed by plants to enter a food chain, so that potential threat is caused to ecological safety and human health. Therefore, the development of the efficient and safe polluted soil restoration technology has important significance. The plant restoration technology has become an important research direction for restoring the soil polluted by the heavy metal at present because of the advantages of low cost, environmental protection, wide application range and the like. The rhodiola rosea is taken as a typical heavy metal super-accumulation plant, has super-strong absorption and enrichment capacities on elements such as cadmium, zinc and the like, and is widely focused in phytoremediation research. However, in the practical application process, a large amount of heavy metals in soil often exist in a indissolvable state or a stable combined state, so that the biological effectiveness is low, and the plant absorption efficiency is limited, so that the repair efficiency is affected. In order to improve phytoremediation efficiency, researchers often add soil activators such as organic acids or chelating agents to the soil to promote the transformation of heavy metals from a steady state to an effective state. However, the conventional activator has a high release rate in soil and is easy to release in a large amount in a short time, so that it is difficult to maintain a continuous activation effect, and the risk of heavy metal migration is increased. Meanwhile, the vernalization in winter in the repair cycle of the rhodiola rosea often enters the reproductive growth stage earlier, so that the vegetative growth is stopped, and the accumulation of plant dry matters and the accumulation of heavy metals are reduced. Therefore, how to regulate and control plant growth rhythm while improving the effectiveness of heavy metals in soil, so that plants can keep higher absorption capacity for a longer time, and realize continuous and stable enrichment of heavy metals is still an important technical problem to be solved in the technical field of phytoremediation. Disclosure of Invention In order to solve the problems, the invention provides a method for regulating and controlling the heavy metal enrichment capability of super-accumulation plants in soil, which comprises the following steps: S1, loading contaminated soil into a pot, namely loading heavy metal contaminated soil into a pot container, and preparing a slow-release soil activator; S2, layering application of a slow-release soil activator, namely applying the slow-release soil activator into pot soil according to 0.3-1.2% of dry weight of polluted soil, uniformly mixing 60-80% of slow-release soil activator with soil within a depth range of 4-8 cm from the surface of the pot soil, applying the rest 20-40% of slow-release soil activator into an annular area which is 2-5 cm away from a plant planting center and is arranged around a pot planting position, and burying the slow-release soil activator into a soil layer which is 2-4 cm away from the surface of the soil; s3, transplanting plants and culturing potted plants, namely transplanting the plants in pot soil after the slow-release soil activator is applied, and culturing the potted plants; S4, gradient spraying control of paclobutrazol, namely, spraying paclobutrazol to plant leaves for 2-4 times 7-15 d after plant transplanting, wherein the paclobutrazol used in each spraying is paclobutrazol aqueous solution with the mass concentration of 180-220 mg/L at intervals of 6-10 d; And S5, feeding back and regulating the growth state of the plant, namely, before the subsequent spraying, regulating the next paclobutrazol spraying amount according to the plant height growth rate, the branch number, the chlorophyll value and/or the flower bud visible rate of the plant so as to improve the enrichment capability of the plant on the heavy metals. The method comprises the steps of applying a slow-release soil activator in heavy metal contaminated soil and regulating and controlling plant growth rhythm by combining paclobutrazol, so that the effective state release process of heavy metal in the soil is matched with the plant vegetative growth period, wherein the slow-release soil activator can continuously rel