Preparation method of invasive biological compost carbon and application of invasive biological compost carbon in selenium-rich low-carbon safe production of arsenic-polluted soil

Abstract

The invention discloses a preparation method of invasive biological compost carbon and application of the invasive biological compost carbon in selenium-rich low-carbon safe production of arsenic-polluted soil. The invasive biological compost carbon is developed by utilizing an invasive plant mikania micrantha and an invasive animal pomacea canaliculata, can be used for planting rice on arsenic-polluted soil, and has the effects of passivating soil arsenic, reducing enrichment of arsenic in each part of the rice and enhancing absorption, transportation and accumulation of selenium. The selenium-rich and low-carbon safe production of crops in the arsenic-polluted soil is realized, and an effective technology is provided for guaranteeing the soil ecological environment and agricultural safe planting. Meanwhile, diffusion and spreading of invasive plants and invasive animals are inhibited to a certain extent, the invasive plants and the invasive animals are recycled, resource waste is reduced, and a new path is provided for prevention and treatment of invasive organisms.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of invasive organisms, and in particular to an invasive organism compost charcoal obtained by mixing selenium-enriched compost of invasive animals and plants with iron-modified biochar. The invasive organism compost charcoal can be used to passivate soil arsenic, improve the quality of arsenic-contaminated soil, and realize selenium-enriched, low-carbon and safe production of rice on arsenic-contaminated soil. Background Art

[0002] Alien species invasion is the second biggest threat to biodiversity after habitat destruction. It not only directly harms human health, but also replaces local dominant species, seriously harms the local ecological environment, and causes huge economic losses. Studies have found that there are currently 488 alien invasive species in my country, mainly invasive plants and animals, of which 265 are invasive plants, accounting for 54.30% of the total number of alien invasive species, and 171 are animals, accounting for 35.04%. At present, biological invasion prevention and control is mainly carried out through artificial prevention, mechanical or physical prevention, chemical prevention and control, and biological prevention and control. The resource utilization of alien invasive organisms is an important means of invasive biological prevention and control. It can not only deal with the harmful wastes of the above-mentioned various prevention and control methods, but also reduce the control cost.

[0003] The golden apple snail (Pomacea canaliculata Lamarck) belongs to the family of bottle snails in the class of gastropoda of the phylum Mollusca and is native to the Amazon River basin in South America. In the 1980s, the golden apple snail was introduced to North America, Europe and Southeast Asia. Due to improper management, it spread with the water flow to rice fields, rivers and ponds, causing serious damage to aquatic crops such as rice, wild rice stems and water chestnuts. Therefore, the IUCN lists it as one of the world's 100 malignant invasive alien species. The golden apple snail has strong adaptability, a variegated diet and fast reproduction. Studies have found that the golden apple snail can reproduce 2 to 3 generations per year, and a female golden apple snail can produce an average of 13,764 eggs per year. The golden apple snail in rice fields has become a key prevention and control target in rice-producing areas. Many provinces in my country have carried out special monitoring and control of the golden apple snail.

[0004] Mikania micrantha is a perennial climbing vine of the Asteraceae family, native to Central and South America, and is one of the world's top ten most invasive weeds. Mikania micrantha was introduced to China in 1910 and has been widely invasive and spread since the 1980s. Mikania micrantha grows rapidly and has strong vitality. Its stems can take root anywhere to form new plants. At the same time, Mikania micrantha indirectly causes the death of host plants by entwining around shrubs and interfering with the normal physiological functions of host plants. At present, this vine has invaded forests, farmlands and orchards in southern China, causing serious damage to local biodiversity and ecosystems.

[0005] The background value of arsenic content in my country's soil is about 11.2 mg / kg, which is twice the average arsenic content in the world's soil. 70% of the world's arsenic mineral resources are located in my country. Soil arsenic contamination areas are concentrated in Yunnan, Hunan and Guangxi, where arsenic reserves are large. Due to backward mining technology and weak environmental awareness, the soil and water bodies in the surrounding areas have suffered varying degrees of heavy metal pollution. At present, the methods for repairing arsenic-contaminated soil include chemical precipitation, plant remediation, ion exchange, adsorption, microbial remediation, etc.

[0006] At present, the problem of arsenic pollution in southern my country is becoming increasingly serious. The migration and transformation of arsenic in the soil-rice field system directly affects the biological effectiveness of arsenic and is related to the safe production of rice. The selection of suitable passivators for rice fields is the key to solving the problem of soil arsenic pollution. At present, there are no reports on the use of selenium-enriched compost of Mikania micrantha and Pomacea canaliculata meat and combined with modified biochar to treat arsenic-contaminated farmland soil. Summary of the invention

[0007] The purpose of the present invention is to overcome the above-mentioned defects and shortcomings in the prior art and provide a method for preparing invasive biocompost charcoal.

[0008] Another object of the present invention is to provide invasive organism compost charcoal prepared by the above preparation method.

[0009] Another object of the present invention is to provide an application of the invasive organism compost charcoal.

[0010] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0011] A method for preparing invasive biocompost charcoal comprises the following steps:

[0012] S1. drying and crushing the cleaned Mikania micrantha; washing the separated Pomacea canaliculata meat;

[0013] S2. The raw materials prepared in step S1 are placed in a composting container according to a carbon-nitrogen ratio of 20 to 30:1, the moisture content is controlled at 55 to 65%, mixed, and evenly sprayed with 1.5 to 4.5 mg / kg of nano-selenium solution before starting composting. The composting days are 45 to 55 days to obtain invasive biological selenium-rich compost;

[0014] S3. Place biochar powder in Fe 2+ with Fe 3+ In the mixed solution, the pH of the system is adjusted to 11-12, and then an aging treatment is performed, followed by suction filtration, drying, and grinding to prepare iron-modified biochar; the Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+The molar ratio is 1.9-2.9:1, and the pH is 4-5;

[0015] S4. Mix the selenium-rich compost of the invasive organisms in step S2 and the iron-modified biochar in step S3 to prepare invasive organism compost charcoal; the mass ratio of the invasive organism compost to the modified biochar is: 0.7-6.5:0.5-6.9.

[0016] In the method of the present invention, the meat of Pomacea canaliculata is used as a nitrogen source for composting, and its protein content is as high as 62%, and it also contains a large amount of minerals and vitamins. Mikania micrantha is used as a carbon source for composting, and Mikania micrantha has a high organic carbon content, which can reach 440.46g / kg, while conventional composting carbon sources are mostly agricultural wastes such as rice straw, corn straw, chestnut shells and sawdust, and their organic carbon contents are only 377.9g / kg, 371.7g / kg, 272.3g / kg and 347.1g / kg respectively. Therefore, composting with Pomacea canaliculata and Mikania micrantha can obtain a compost product with a higher organic matter content, and at the same time, too high a concentration of selenium has a toxic effect on crops, so the present invention also selects a suitable selenium concentration for selenium-enriched composting to promote the growth of crops. The present invention comprehensively considers that selenium-rich compost helps to improve soil quality and promote selenium-rich crop growth, and biochar has adsorption capacity. The adsorption performance of biochar is improved by iron modification technology, and then the selenium-rich compost and iron-modified biochar are mixed in a certain proportion to form invasive biological compost charcoal, which is more helpful for repairing heavy metal contaminated soil and selenium-rich crop growth. Therefore, the present invention synthesizes invasive biological compost charcoal by a certain proportion of invasive biological selenium-rich compost and iron-modified biochar, and obtains a series of invasive biological compost charcoals that passivate soil arsenic, improve arsenic-contaminated soil, enrich selenium, and low-carbon safe production of rice on arsenic-contaminated soil, which not only successfully develops a new method for repairing arsenic-contaminated soil and enriching selenium, but also provides a new way for effectively utilizing invasive biological resources.

[0017] The invention prepares invasive organism selenium-rich compost and iron-modified biochar according to a response surface optimization process under the conditions of different iron modification molar ratios, different modified biochar addition amounts and different selenium-rich compost addition amounts to obtain invasive organism compost charcoal I, invasive organism compost charcoal II and invasive organism compost charcoal III.

[0018] Furthermore, the Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio of the invasive organism selenium-enriched compost to the iron-modified biochar is 1.9-2.3:1; the mass ratio of the invasive organism selenium-enriched compost to the iron-modified biochar is 2.6-4.2:4.8-6.9. The invasive organism compost charcoal I is obtained, which is mainly used to passivate the effective arsenic content of arsenic-contaminated soil in rice roots and reduce the arsenic content in various parts of rice.

[0019] Preferably, the Fe2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 2.07:1; the mass ratio of the invasive organism selenium-rich compost to the iron-modified biochar is 2.96:4.91.

[0020] Furthermore, the Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 2.4-2.6:1; the mass ratio of the invasive organism selenium-enriched compost to the iron-modified biochar is 0.7-2.5:2.5-4.7. The invasive organism compost charcoal II is obtained, which is mainly used to improve the quality of arsenic-contaminated soil in the rhizosphere of rice, increase the enzyme activity of arsenic-contaminated soil, and realize low-carbon rice planting.

[0021] Preferably, the Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 2.5:1; the mass ratio of the invasive organism selenium-rich compost to the iron-modified biochar is 1.8:4.1.

[0022] Furthermore, the Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 2.7-2.9:1, and the mass ratio of the invasive organism selenium-enriched compost to the iron-modified biochar is 4.3-6.5:0.5-2.4. The invasive organism compost charcoal III is obtained, which is mainly used to improve the quality of rice in arsenic-contaminated soil, promote the formation of iron film on rice roots, and realize selenium-enriched rice production.

[0023] Preferably, the Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 2.4:1; the mass ratio of the invasive organism selenium-rich compost to the iron-modified biochar is 5.2:2.1.

[0024] Furthermore, the crushing in step S1 is to crush the Mikania micrantha into 2-3 cm.

[0025] Furthermore, the drying temperature in step S1 is 60-80° C., and the drying time is 48-72 hours.

[0026] Furthermore, the carbon-nitrogen ratio in step S2 is 21:1.

[0027] Furthermore, the moisture content in step S2 is 60%.

[0028] Furthermore, the concentration of the nano-selenium solution in step S2 is 2 mg / kg.

[0029] Furthermore, the stacking days in step S2 are 50 days.

[0030] Furthermore, the specific surface area of ​​the biochar powder in step S3 is 10.18 to 40.89 m 2 / g, and the pore size is 9.58~15.27nm.

[0031] Furthermore, the biochar powder is commercial rice straw biochar powder purchased from Henan Housen Environmental Protection Technology Co., Ltd.

[0032] Furthermore, in step S3, the pH of the regulating system is adjusted to 11.5.

[0033] Further, the Fe in step S3 2+ with Fe 3+ The pH value of the mixed solution is 4.5. Furthermore, the aging treatment time in step S3 is 3 to 4 hours, the drying temperature is 60 to 80° C., and the drying time is 48 to 72 hours.

[0034] The present invention also provides invasive organism compost charcoal prepared by any of the above preparation methods.

[0035] The invasive organism compost charcoal of the present invention can be used for planting rice on arsenic-contaminated soil, to passivate soil arsenic, reduce arsenic enrichment in various parts of rice, and enhance the absorption, transport and accumulation of selenium.

[0036] Therefore, the present invention also provides the use of the above-mentioned invasive organism compost charcoal in passivating soil arsenic, improving the quality of arsenic-contaminated soil, and achieving low-carbon and selenium-enriched crops on arsenic-contaminated soil.

[0037] When the invasive organism compost charcoal of the present invention is used, it can be applied in the following manner: according to the total weight of the soil, the invasive organism compost charcoal is weighed, directly added into the soil and mixed, and then rice is planted.

[0038] Furthermore, when applying invasive organism compost charcoal I, the addition ratio of invasive organism selenium-enriched compost and iron-modified biochar in arsenic-contaminated soil is 0.7% to 2.5%: 2.5% to 4.7%.

[0039] Preferably, when applying invasive organism compost charcoal I, the addition ratio of invasive organism selenium-enriched compost and iron-modified biochar in arsenic-contaminated soil is 2.96%:4.91%.

[0040] Furthermore, when applying invasive organism compost charcoal II, the addition ratio of invasive organism selenium-enriched compost and iron-modified biochar in arsenic-contaminated soil is 0.7% to 2.5%: 2.5% to 4.7%.

[0041] Preferably, when applying invasive organism compost charcoal II, the addition ratio of invasive organism selenium-enriched compost and iron-modified biochar in arsenic-contaminated soil is 1.8%:4.1%.

[0042] Furthermore, when applying invasive organism compost charcoal III, the addition ratio of invasive organism selenium-enriched compost and iron-modified biochar in arsenic-contaminated soil is 4.3% to 6.5%: 0.5% to 2.4%.

[0043] Preferably, when applying invasive organism compost charcoal III, the addition ratio of invasive organism selenium-enriched compost to iron-modified biochar in arsenic-contaminated soil is 5.2%:2.1%.

[0044] Furthermore, the arsenic content in the arsenic-contaminated soil is 50-100 mg / kg.

[0045] The present invention uses the passivation efficiency of arsenic-contaminated soil and the arsenic content of each part of rice as effect verification. The above-mentioned invasive biological compost charcoal is mixed evenly and applied to the arsenic-contaminated soil; the arsenic concentration of the arsenic-contaminated soil is 50-100 mg / kg. The above-mentioned invasive biological compost charcoal of the present invention can play a role in passivating soil arsenic, improving the quality of arsenic-contaminated soil and the safe production of rice in arsenic-contaminated soil, and has a certain reference and reference significance for the remediation of other heavy metal-contaminated soils.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention uses the invasive plant Mikania micrantha and the invasive animal Pomacea canaliculata to develop invasive biological compost charcoal, the organic matter content of which is 65%, which is higher than the organic fertilizer on the market (30% to 45%). At the same time, it can be used for rice planting on arsenic-contaminated soil, and has the functions of passivating soil arsenic, reducing the enrichment of arsenic in various parts of rice, and enhancing the absorption, transportation and accumulation of selenium. It not only realizes the safe production of crops in arsenic-contaminated soil with rich selenium and low carbon, but also provides an effective technology for protecting the soil ecological environment and agricultural safe planting. At the same time, it inhibits the spread of invasive plants and invasive animals to a certain extent, utilizes them as resources, reduces their waste of resources, and provides a new path for the prevention and control of invasive organisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Effects of invasive biocompost charcoal I on arsenic forms in arsenic-contaminated soils.

[0049] Figure 2 Effects of invasive biocompost charcoal I on arsenic content in roots of different rice varieties grown in arsenic-contaminated soil.

[0050] Figure 3 Effects of invasive biocompost charcoal I on arsenic content in stems and leaves of different rice varieties in arsenic-contaminated soil.

[0051] Figure 4 Effects of invasive biocompost charcoal I on arsenic content in rice husks of different rice varieties in arsenic-contaminated soil.

[0052] Figure 5 Effects of invasive biocompost charcoal I on arsenic content in rice grains of different varieties grown in arsenic-contaminated soil.

[0053] Figure 6 Effect of invasive biocompost charcoal II on sucrase activity in arsenic-contaminated soil.

[0054] Figure 7 Effect of invasive biocompost charcoal II on urease activity in arsenic-contaminated soil.

[0055] Figure 8 Effect of invasive biocompost charcoal II on acid phosphatase activity in arsenic-contaminated soil.

[0056] Fig. 9 Effects of invasive biocompost charcoal II on cumulative methane emissions from different rice varieties in arsenic-contaminated soil.

[0057] Fig.10 Effects of invasive biocompost charcoal II on the warming potential of different rice varieties in arsenic-contaminated soil.

[0058] Fig.11 Effects of invasive biocompost charcoal III on the iron film on the surface of rice roots in arsenic-contaminated soil.

[0059] Fig.12 Effects of invasive biocompost charcoal III on selenium content in grains of different rice varieties grown in arsenic-contaminated soil. DETAILED DESCRIPTION

[0060] The present invention is further described below in conjunction with the accompanying drawings and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0061] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0062] Commercial rice straw biochar was purchased from Henan Housen Environmental Protection Technology Co., Ltd. (pyrolysis at 500 °C, 100 mesh sieve), with a specific surface area of ​​10.18-40.89 m 2 / g, and the pore size is 9.58~15.27nm.

[0063] Example 1 Response surface optimization preparation of invasive organism compost charcoal I

[0064] This formula is mainly used to passivate the effective arsenic content in arsenic-contaminated soil in the rice roots and reduce the arsenic content in various parts of rice.

[0065] (1) Collection of Mikania micrantha and Pomacea canaliculata

[0066] The invasive plant Mikania micrantha was collected, dried in an oven at 60-80℃, and then cut into 2-3 cm pieces for later use; the invasive animal Pomacea canaliculata was collected, frozen to death at -20℃, and the snail meat was separated with tweezers. After the snail meat was cleaned, it was stored in a -20℃ refrigerator for later use.

[0067] (2) Selenium-enriched composting of invasive organisms: The materials described in step (1) are placed in a composting barrel at a carbon-nitrogen ratio of 21:1, and the moisture content is controlled at about 60%. All the materials in the barrel are mixed evenly, and 2 mg / kg (based on the total weight of the materials) of nano-selenium (SeNPs) is evenly sprayed before composting. The composting period is 50 days.

[0068] (3) Preparation of iron-modified biochar: Rice straw biochar is commercial biochar. The biochar powder is placed in an iron solution, the pH of the system is adjusted to 11.5, and then aged. The iron-modified biochar is then filtered, dried, and ground. 2+ with Fe 3+ The molar ratio is 1.9-2.9:1, and the pH is 4.5.

[0069] (4) Response surface optimization design of invasive organism composting charcoal I

[0070] The Box-Behnken design based on the response surface model was used to analyze the interaction effects between variables and obtain a second-order quadratic polynomial equation to predict the response, which can be quantitatively described as a quadratic function of three variables. Equation (1) can be expressed as follows:

[0071]

[0072] Where: α 0 represents the intercept, α 1 α 2 α 3 represents the linear coefficient, α 12 α 13 α 23 represents the interaction coefficient, α 11 α 22 α 33 represents the quadratic coefficient.

[0073] Three factors affecting the passivation rate of effective arsenic in arsenic-contaminated soil were selected: Fe in iron-modified biochar 2+ with Fe 3+The three parameters of molar ratio (X1), modified biochar (MB) addition (X2), and invasive biological compost (SC) addition (X3) were optimized. The variance analysis in Design Expert 11 software was used to design the experimental scheme and analyze the results. A 3-factor 3-level experimental combination was designed, as shown in Table 1. The biochar Fe 2+ and Fe 3+ The materials obtained in steps (2) and (3) are added to arsenic-contaminated soil at a molar ratio of 1:1, 2:1 and 3:1, with the addition amount of modified biochar being 1% to 6% and the addition amount of invasive biological compost being 1% to 5%.

[0074] Table 1 Factors and experimental design levels of Box-Behnken design

[0075]

[0076] (5) Optimization of the preparation of invasive biocompost charcoal I

[0077] According to the optimized conditions obtained by response surface methodology, the following mass percentages are used: Fe 2+ with Fe 3+ The molar ratio is 1.9-2.3:1, invasive biocompost: modified biochar = 2.6%-4.2%: 4.8%-6.9%, and the resulting invasive biocompost charcoal I is added to 1 kg of arsenic-contaminated soil. The optimal concentration is Fe in the iron solution. 2+ with Fe 3+ The molar ratio was 2.07:1, the addition amount of invasive organism compost was 2.96%, and the addition amount of modified biochar was 4.91%.

[0078] Specifically, FeSO 4 7H 2 O and FeCl 3 6H 2 O was dissolved in deoxygenated water to prepare a final concentration of 2.07 mol / LFeSO 4 7H 2 O and 1 mol / L FeCl 3 6H 2 The solution of arsenic was adjusted to pH 4.5 with 1.5 mol / L NaOH solution, and 5 g of biochar material was added to the solution to adjust the pH to 11.5. The mixture was aged in the mother liquor for 3 hours, filtered, dried at 60 ° C, and ground for use. For 1 kg of soil, 29.6 g of invasive biological compost and 49.1 g of modified biochar were combined to form a complex, which was then added to the arsenic-contaminated soil.

[0079] Application Example 1 Effects of invasive organism compost charcoal I on the content of available As in As-contaminated soil in the rhizosphere of different rice varieties

[0080] 1. Methods

[0081] This application case explores the passivation effect of invasive biocompost charcoal I on available As in rhizosphere As-contaminated soil of different rice varieties. The specific steps are as follows:

[0082] (1) Prepare optimized invasive organism composting charcoal I according to the conditions of the aforementioned Example 1.

[0083] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0084] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and 6 kg of test soil per pot. During the growth period of rice, the pot was kept at a water depth of 4 cm. The pot was flooded throughout the growth period, and no water was added one week before the rice harvest.

[0085] (4) All 10 rice varieties used in the experiment were set up as control (CK) and treatment (T). All treatments (T) were based on the invasive biocompost charcoal I (Fe 2+ with Fe 3+ The molar ratio was 2.07:1, invasive biocompost: modified biochar = 2.96%: 4.91%), and the control was without compost charcoal, with 4 replicates. Soil samples were collected at the 6th and 12th week of rice transplanting and at harvest.

[0086] (5) Extraction and determination of available arsenic: Weigh 1 g of soil sample (accurate to 0.0001 g) into a 50 mL centrifuge tube and add 25 mL of 0.05 mol / L NH 4 H 2 PO 4 The solution (soil-water ratio of 1:25) was shaken in a constant temperature shaker at 20°C for 16 h, then centrifuged in a centrifuge at 4000 r / min for 10 min, filtered and measured using an atomic fluorescence spectrometer.

[0087] 2. Results

[0088] The effects of invasive biological compost charcoal I on the available arsenic in the rhizosphere soil of rice are shown in Table 2. It can be seen that the available arsenic content in all treatments gradually decreased. In the first 6 weeks after rice transplanting, invasive biological compost charcoal I had a greater effect on the available arsenic content in the soil of each treatment, and the decline rate of available arsenic in each treatment was 41-49%, which was in the rapid passivation stage of arsenic, while the available arsenic content in the soil of each control changed slowly (1-2%). From the 6th to the 12th week, the change rate of available arsenic content in the soil with invasive biological compost charcoal I gradually decreased, ranging from 16 to 24%, while the change of available arsenic in the control was relatively stable, with a decline rate of 1-3%. At the end of the experiment, the average available arsenic content in the soil treated with invasive biological compost charcoal I was 2.98 mg / kg, which was 61% lower than that in the control. The decline rate of available arsenic in the entire growth period of rice was 59-71%, which was significantly higher than the control of 7-15% (P < 0.05).

[0089] Table 2 Effects of invasive biocompost charcoal I on available arsenic in rhizosphere soil of different rice varieties

[0090]

[0091] Note: (CK) in the same variety stands for control; (T) stands for treatment - application of invasive biological compost and biochar; Different lowercase letters in the same column indicate significant differences, P < 0.05.

[0092] Application Example 2 Effects of invasive biocompost charcoal I on As forms in As-contaminated soils in the rhizosphere of different rice varieties

[0093] 1. Methods

[0094] This application case explores the effect of invasive biocompost charcoal I on the transformation of As forms in As-contaminated soils in the rhizosphere of different rice varieties. The specific steps are as follows:

[0095] (1) Prepare optimized invasive organism composting charcoal I according to the conditions of the aforementioned Example 1.

[0096] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0097] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and 6 kg of test soil per pot. During the growth period of rice, the pot was kept at a water depth of 4 cm. The pot was flooded throughout the growth period, and no water was added one week before the rice harvest.

[0098] (4) All 10 rice varieties used in the experiment were set up as a control (CK) and a treatment (T). All treatments (T) were added with invasive biocompost charcoal I (Fe 2+ with Fe 3+ The molar ratio was 2.07:1, invasive biocompost: modified biochar = 2.96%: 4.91%), and the control was without compost charcoal, with 4 replicates. Soil samples were collected when rice was harvested.

[0099] (5) Extraction and determination of soil arsenic forms: Based on the different activities of different forms of heavy metals in the soil, the potential toxicity and environmental risks of heavy metals in the soil environment can be analyzed and explored. The extraction of different forms of arsenic in the soil was carried out using the Tessier extraction method. Tessier divides the arsenic forms in the soil into five forms: exchangeable state (EXC), carbonate bound state (CAR), iron-manganese oxide bound state (OX), organic matter bound state (OM) and residual state (RES). The extracts of the above five steps were measured using an atomic fluorescence spectrometer to analyze the distribution of heavy metal arsenic forms.

[0100] 2. Results

[0101] The results of the effects of invasive biocompost charcoal I on arsenic forms in arsenic-contaminated soils are shown in Figure 2. Figure 1 As shown in the results, in this test, the overall proportion of soil arsenic forms was residual > iron-manganese oxide bound > carbonate bound > organic bound > exchangeable, among which the residual accounted for the highest proportion. The exchangeable arsenic and carbonate bound contents of the soil treated with invasive biocompost charcoal I were significantly reduced (P < 0.05). Compared with the controls, the exchangeable arsenic content in the treatment decreased by 46-60%, and the carbonate bound state decreased by 46-74%. Invasion of biocompost charcoal I significantly increased the organic bound and residual arsenic contents in each treatment compared with the control (P < 0.05), among which the organic bound state increased by 6-10%, and the residual state accounted for 64-67% of the total arsenic content.

[0102] Application Example 3 Effects of invasive biocompost charcoal I on arsenic content in various parts of different rice varieties in arsenic-contaminated soil

[0103] 1. Methods

[0104] This application case explores the effect of invasive biocompost charcoal I on reducing the arsenic content in different parts of rice varieties in arsenic-contaminated soil. The specific steps are as follows:

[0105] (1) Prepare invasive biocompost charcoal I according to the conditions of Example 1 above.

[0106] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0107] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and 6 kg of test soil per pot. During the growth period of rice, the pot was kept at a water depth of 4 cm. The pot was flooded throughout the growth period, and no water was added one week before the rice harvest.

[0108] (4) All 10 rice varieties used in the experiment were set up as a control (CK) and a treatment (T). All treatments (T) were added with invasive biocompost charcoal I (Fe 2+ with Fe 3+ The molar ratio was 2.07:1, invasive biocompost: modified biochar = 2.96%: 4.91%), and the control was without compost charcoal. Four replicates were set. After the rice matured, the whole plants were collected.

[0109] (5) Determination of arsenic content in various parts of rice: Graphite furnace digestion instrument was used for digestion and atomic fluorescence spectrophotometry was used for determination.

[0110] 2. Results

[0111] Effects of invasive biocompost charcoal I on arsenic content in different rice varieties in arsenic-contaminated soil Figure 2 to Figure 5 As shown in the figure, overall, the arsenic content in each part of rice is: root > stem and leaf > rice husk > grain. Among all CKs, the arsenic content of roots, stems and leaves, grains and rice husks of 10 rice varieties ranged from 197.32 to 356.29 mg / kg, 5.83 to 6.43 mg / kg, 0.27 to 0.57 mg / kg and 1.15 to 1.54 mg / kg, respectively. The arsenic content in rice grains is an important indicator of safe rice consumption. According to the provisions of the National Food Safety Standard Limits of Contaminants in Food (GB2762-2017), under high arsenic pollution in the soil, the arsenic content of the 10 rice varieties in the control group was higher than the arsenic content limit (0.2 mg / kg) specified in the national food safety standard.

[0112] Invasive biocompost charcoal I caused changes in the arsenic content in various parts of different rice varieties. Compared with the control, the arsenic accumulation in the roots of different rice varieties was significantly reduced (P < 0.05), with a reduction range of 25-49%. The arsenic content in the stems and leaves of different rice varieties decreased by 32-46%. In the treatment without the application of invasive biocompost charcoal, the arsenic content of the grains of 10 rice varieties exceeded the arsenic content limit (0.2 mg / kg) in the national food safety standard. After the application of invasive biocompost charcoal, the arsenic content in the grains of different rice varieties decreased by 23-41%, among which the arsenic content in the grains of Meixiangzhan No. 2, Xiangyazhan and Nanjingxiangzhan decreased to 0.18 mg / kg, 0.17 mg / kg and 0.19 mg / kg, respectively, which met the national food safety standard. In addition, the arsenic content in rice husks showed great differences after the application of invasive biological compost charcoal I. The arsenic content in rice varieties 19xiang, Jinke Simiao 2, Erguangxiangzhan, Jitianyouhuazhan and Jingliangyou 1212 was significantly reduced, with the reduction ranging from 9 to 18%.

[0113] Example 2 Preparation of Invasive Biocompost Charcoal II

[0114] This formula is mainly used to improve the quality of arsenic-contaminated soil in the rhizosphere of rice, increase the enzyme activity of arsenic-contaminated soil, and achieve low-carbon rice cultivation.

[0115] (1) Collection of Mikania micrantha and Pomacea canaliculata

[0116] The invasive plant Mikania micrantha was collected, dried in an oven at 60-80℃, and then cut into 2-3 cm pieces for later use; the invasive animal Pomacea canaliculata was collected, frozen to death at -20℃, and the snail meat was separated with tweezers. After the snail meat was cleaned, it was stored in a -20℃ refrigerator for later use.

[0117] (2) Selenium-enriched composting of invasive organisms: The materials described in step (1) are placed in a composting barrel at a carbon-nitrogen ratio of 21:1, and the moisture content is controlled at about 60%. All the materials in the barrel are mixed evenly, and 2 mg / kg (based on the total weight of the materials) of nano-selenium (SeNPs) is evenly sprayed before composting. The composting period is 50 days.

[0118] (3) Preparation of iron-modified biochar: Rice straw biochar is commercial biochar. The rice straw biochar powder is placed in an iron solution, the pH of the system is adjusted to 11.5, and then aged, filtered, dried, and ground to prepare iron-modified biochar; the iron solution contains Fe 2+ with Fe 3+ The molar ratio is 1.9-2.9:1, and the pH is 4.5.

[0119] (4) Preparation of invasive biocompost charcoal II

[0120] The optimized modification condition range obtained by the response surface methodology is as follows: Fe in the iron solution 2+with Fe 3+ The molar ratio is 2.4-2.6:1, invasive biocompost: modified biochar = 0.7%-2.5%: 2.5%-4.7%, and the resulting invasive biocompost charcoal II is added to 1 kg of arsenic-contaminated soil. The optimal concentration is Fe in the iron solution. 2+ with Fe 3+ The molar ratio was 2.5:1, the amount of invasive organism compost added was 1.8%, and the amount of modified biochar added was 4.1%.

[0121] Specifically, FeSO 4 7H 2 O and FeCl 3 6H 2 O was dissolved in deoxygenated water to prepare a final concentration of 2.5 mol / LFeSO 4 7H 2 O and 1 mol / L FeCl 3 6H 2 O solution, the pH was adjusted to 4.5 with 1.5mol / LNaOH solution, 5g of biochar material was added to the solution and the pH was adjusted to 11.5, the mixture was aged in the mother liquor for 3 hours and then filtered, dried at 60℃ and ground for use. For 1kg of soil, 18g of invasive biological compost and 41g of modified biochar were combined to form a complex, which was then added to the arsenic-contaminated soil.

[0122] Application Example 4 Effect of invasive organism compost charcoal II on improving the quality of As-contaminated soil in the rhizosphere of different rice varieties

[0123] 1. Methods

[0124] This application case explores the effect of invasive biocompost charcoal II on the quality of As-contaminated soil in the rhizosphere of different rice varieties. The specific steps are as follows:

[0125] (1) Prepare invasive biocompost charcoal II according to the conditions of Example 2 above.

[0126] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0127] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and 6 kg of test soil per pot. During the growth period of rice, the pot was kept at a water depth of 4 cm. The pot was flooded throughout the growth period, and no water was added one week before the rice harvest.

[0128] (4) All 10 rice varieties used in the experiment were set up as a control (CK) and a treatment (T). All treatments (T) were added with invasive biocompost charcoal II (Fe 2+ with Fe 3+ The molar ratio was 2.5:1, invasive biocompost: modified biochar = 1.8%:4.1%), and the control was without compost charcoal, with 4 replicates. Soil samples were collected when rice was harvested.

[0129] (5) The determination of soil physical and chemical indicators refers to "Soil Agrochemical Analysis". Use a pH meter (PHSJ-4F) and a conductivity meter (DDS-307) to determine soil pH and conductivity at a solid-liquid ratio of 1:2.5 and 1:5, respectively; soil organic matter is determined by potassium dichromate-concentrated sulfuric acid external heating method; soil alkaline nitrogen is determined by diffusion dish titration method; soil available phosphorus is determined by sodium bicarbonate extraction-molybdenum antimony colorimetric method; soil available potassium is determined by sodium acetate extraction-flame photometry.

[0130] 2. Results

[0131] The effects of invasive biological compost charcoal II on the physical and chemical properties of arsenic-contaminated soil are shown in Table 3. It can be seen that invasive biological compost charcoal II has a significant effect on the pH, conductivity, organic matter and soil available nutrients (N, P and K) of paddy soil (P < 0.05). After the application of invasive biological compost charcoal II to paddy soil, the pH value of each treatment was significantly reduced by 3% to 8% compared with the control. On the contrary, the soil conductivity increased by 66 to 171% compared with the control. At the same time, compost charcoal has a significant effect on improving the content of soil organic matter, alkaline nitrogen, available phosphorus and available potassium (P < 0.05), with the organic matter content increasing by 0.26 to 0.65 times, the alkaline nitrogen content increasing by 0.41 to 1.09 times, the available phosphorus increasing by 0.19 to 0.35 times, and the available potassium increasing by 0.90 to 1.19 times.

[0132] Table 3 Effects of invasive biocompost charcoal II on the physical and chemical properties of arsenic-contaminated soil

[0133]

[0134]

[0135]

[0136] Note: In the same variety, (CK) represents the control, (T) represents the treatment with invasive organism compost and biochar; different letters in the same column indicate significant differences (P<0.05).

[0137] Application Example 5 Effect of invasive biocompost charcoal II on improving enzyme activities in rhizosphere soils contaminated by As in different rice varieties

[0138] 1. Methods

[0139] This application case explores the effect of invasive biocompost charcoal II on soil enzyme activity in the rhizosphere of As-contaminated soil of different rice varieties. The specific steps are as follows:

[0140] (1) Prepare invasive biocompost charcoal II according to the conditions of Example 2 above.

[0141] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0142] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and 6 kg of test soil per pot. During the growth period of rice, the pot was kept at a water depth of 4 cm. The pot was flooded throughout the growth period, and no water was added one week before the rice harvest.

[0143] (4) All 10 rice varieties used in the experiment were set up as a control (CK) and a treatment (T). All treatments (T) were added with invasive biocompost charcoal II (Fe 2+ with Fe 3+ The molar ratio was 2.5:1, invasive biocompost: modified biochar = 1.8%: 4.1%), and the control was without compost charcoal, with 4 replicates. Soil samples were collected when rice was harvested.

[0144] (5) The activity of soil urease was determined by the phenol-sodium hypochlorite colorimetric method; the activity of soil sucrase was determined by the 3,5-dinitrosalicylic acid colorimetric method; and the activity of soil acid phosphatase was determined by the disodium phenyl phosphate colorimetric method.

[0145] 2. Results

[0146] Effects of invasive biocompost charcoal II on sucrase activity in arsenic-contaminated soil Figure 6As shown, compost charcoal increased the soil sucrase activity in each treatment to varying degrees, with the increase ranging from 58% to 122% (P < 0.05). At the end of the experiment, the soil sucrase activity in the Yoshida Yuhua treatment was the highest, reaching 16.42 mg / g / 24h.

[0147] Effects of invasive biocompost charcoal II on urease activity in arsenic-contaminated soil Figure 7 As shown, compared with the control, the soil urease activity was increased by 61-98%, among which the compost charcoal had the greatest effect on the soil urease activity of Yoshida Yuhuazan variety.

[0148] Effects of invasive biocompost charcoal II on acid phosphatase activity in arsenic-contaminated soil Figure 8 As shown in the figure, compost charcoal increased the acid phosphatase activity in the soil of different rice varieties to varying degrees. Among them, the phosphatase activity in the soil of the 19 fragrant rice variety increased the most, with a phosphatase activity of 1.08 mg / g / 24h.

[0149] Application Example 6 Effects of invasive biocompost charcoal II on greenhouse gas emissions from different rice varieties in arsenic-contaminated soil

[0150] 1. Methods

[0151] This application case explores the effects of invasive biocompost charcoal II on greenhouse gas emissions from different rice varieties grown in arsenic-contaminated soil. The specific steps are as follows:

[0152] (1) Prepare invasive biocompost charcoal II according to the conditions of Example 2 above.

[0153] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0154] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and 6 kg of test soil per pot. During the growth period of rice, the pot was kept at a water depth of 4 cm. The pot was flooded throughout the growth period, and no water was added one week before the rice harvest.

[0155] (4) All 10 rice varieties used in the experiment were set up as a control (CK) and a treatment (T). All treatments (T) were added with invasive biocompost charcoal II (Fe 2+ with Fe 3+ Molar ratio 2.5, invasive organism compost: modified biochar = 1.8%: 4.1%), control without compost charcoal, set 4 replicates.

[0156] (5) The rice pot greenhouse gas collection was carried out using the static box method. The sampling time was from 9:00 to 11:00 in the morning. During sampling, a 50 mL syringe was used to extract the gas and a three-way valve was used to lock the gas to prevent leakage. Gas samples were collected at 0, 10, 20, and 30 minutes after the box was sealed. The gas samples were brought back to the laboratory and the methane and nitrous oxide concentrations were determined using a gas chromatograph A7890b within 3 days.

[0157] 2. Results

[0158] Effects of invasive biocompost charcoal II on cumulative methane emissions from different rice varieties in arsenic-contaminated soils Fig. 9 As shown in the figure, the methane emissions of different rice varieties in arsenic-contaminated soil vary greatly, with 19-spice having the lowest cumulative emission of 108.45 kg / hm 2 After the compost charcoal was applied to the soil, the cumulative methane emissions of different rice varieties were significantly reduced (P < 0.05), with the reduction ranging from 12.03% to 33.44%, among which the reduction effect of Rhizoma Coptidis was the best.

[0159] The results of the effects of invasive biocompost charcoal II on the warming potential of different rice varieties in arsenic-contaminated soil are shown in Figure 2. Fig.10 As shown in the figure, there is a large difference in GWP between different rice varieties. When no compost charcoal is applied, the GWP of Jingliangyou 1212 is the largest, reaching 3909.35 kg / hm 2 , while 19 Xiang and Mei Xiang Zhan 2 showed relatively low GWP, with potential values ​​of 2878.13 kg / hm 2 and 2943.24kg / hm 2 After applying compost charcoal, the GWP of Jingliangyou 1212, 19xiang and Meixiangzhan 2 were 3338.19 kg / hm 2 、2572.74kg / hm 2 and 2140.98kg / hm 2 Compared with the control, the GWP of all treatments decreased by 11-27%, indicating that compost charcoal can promote rice growth while reducing warming potential.

[0160] Example 3 Preparation of Invasive Biocompost Charcoal III

[0161] This formula is mainly used to improve the quality of rice grown in arsenic-contaminated soil, promote the formation of iron film on rice roots, and achieve selenium-enriched rice production.

[0162] (1) Collection of Mikania micrantha and Pomacea canaliculata

[0163] The invasive plant Mikania micrantha was collected, dried in an oven at 60-80℃, and then cut into 2-3 cm pieces for later use; the invasive animal Pomacea canaliculata was collected, frozen to death at -20℃, and the snail meat was separated with tweezers. After the snail meat was cleaned, it was stored in a -20℃ refrigerator for later use.

[0164] (2) Selenium-enriched composting of invasive organisms: The materials described in step (1) are placed in a composting barrel at a carbon-nitrogen ratio of 21:1, and the moisture content is controlled at about 60%. All the materials in the barrel are mixed evenly, and 2 mg / kg (based on the total weight of the materials) of nano-selenium (SeNPs) is evenly sprayed before composting. The composting period is 50 days.

[0165] (3) Preparation of iron-modified biochar: Rice straw biochar is commercial biochar. The rice straw biochar powder is placed in an iron solution, the pH of the system is adjusted to 11.5, and then aged, filtered, dried, and ground to prepare iron-modified biochar; the iron solution contains Fe 2+ with Fe 3+ The molar ratio is 1.9-2.9:1, and the pH is 4.5.

[0166] (4) Optimization of the preparation of invasive biocompost charcoal III

[0167] The modification condition range obtained by response surface methodology is as follows: Fe in iron solution 2+ with Fe 3+ The molar ratio is 2.7-2.9:1, invasive biocompost: modified biochar = 4.3%-6.5%: 0.5%-2.4%, and the resulting invasive biocompost charcoal III is added to 1 kg of arsenic-contaminated soil. The optimal concentration is Fe in the iron solution. 2+ with Fe 3+ The molar ratio is 2.8:1, invasive organism compost: modified biochar = 5.2%: 2.1%.

[0168] Specifically, FeSO 4 7H 2 O and FeCl 3 6H 2 O was dissolved in deoxygenated water to prepare a final concentration of 2.8 mol / LFeSO 4 7H 2 O and 1 mol / L FeCl 3 6H 2O solution, the pH was adjusted to 4.5 with 1.5 mol / L NaOH solution, 5 g of biochar material was added to the solution and the pH was adjusted to 11.5, the mixture was aged in the mother liquor for 3 hours, filtered, dried at 60 ° C and ground for use. For 1 kg of soil, 52 g of invasive biological compost and 21 g of modified biochar were combined to form a complex and then added to the arsenic-contaminated soil.

[0169] Application Example 7 Effects of Invasive Biocompost Carbon III on the Growth and Yield of Different Rice Varieties in Arsenic-Contaminated Soil

[0170] 1. Methods

[0171] This application case explores the effect of invasive biocompost charcoal III on the growth and yield of different varieties of rice in arsenic-contaminated soil. The specific steps are as follows:

[0172] (1) Prepare optimized invasive biocompost charcoal III according to the conditions of the aforementioned Example 3.

[0173] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0174] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and 6 kg of test soil per pot. During the growth period of rice, the pot was kept at a water depth of 4 cm. The pot was flooded throughout the growth period, and no water was added one week before the rice harvest.

[0175] (4) All 10 rice varieties used in the experiment were set up as a control (CK) and a treatment (T). All treatments (T) were added with compost charcoal III (Fe 2+ with Fe 3+ The molar ratio was 2.8:1, invasive biocompost: modified biochar = 5.2%: 2.1%), and the control was without compost charcoal, with 4 replicates. After the rice matured, the whole plants were collected.

[0176] (5) Determination of rice plant height and biomass: The collected rice plants were washed with pure water and the surface moisture was wiped off. They were then placed horizontally on a table. The distance from the top of the rice to the root was measured with a tape measure as the plant height. After the rice was dried to a constant weight, the dry matter mass of each part of the rice was weighed with a 1 / 10,000 balance. The number of rice grains per panicle and the thousand-grain weight were all per plant.

[0177] 2. Results

[0178] The results of the effects of invasive organism compost charcoal III on the growth and yield of different rice varieties in arsenic-contaminated soil are shown in Table 4. Invasive organism compost charcoal III improved the growth and yield components of different rice varieties under arsenic stress (P < 0.05), but the improvement effects were different. Specifically, compared with the control, the plant height of different rice varieties increased by 5-15% after applying compost charcoal; in terms of crop yield components, the number of grains per panicle increased by 7-15%, the 1000-grain weight increased by 5-16%, and the yield of each rice plant increased by 15-30%. Compost charcoal had the best yield-increasing effect on the Nanjing Xiangzhan variety.

[0179] Table 4 Effects of invasive biocompost charcoal III on the growth and yield of different rice varieties in arsenic-contaminated soil

[0180]

[0181] Note: In the same variety, (CK) represents the control; (T) represents the treatment with invasive biological compost charcoal; Numbers with different letters in the same column indicate significant differences (P<0.05).

[0182] Application Example 8 Effects of Invasive Biocompost Carbon III on the Iron Film on the Root Surfaces of Different Rice Varieties in Arsenic-Contaminated Soil

[0183] 1. Methods

[0184] This application case explores the effect of invasive biocompost charcoal III on the iron film on the root surface of different rice varieties in arsenic-contaminated soil. The specific steps are as follows:

[0185] (1) Prepare optimized invasive biocompost charcoal III according to the conditions of the aforementioned Example 3.

[0186] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0187] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and about 6 kg of test soil per pot. During the growth period of rice, the pot was kept 4 cm deep in water, and the pot was flooded throughout the growth period. No water was added one week before the rice harvest.

[0188] (4) All 10 rice varieties used in the experiment were set up as a control (CK) and a treatment (T). All treatments (T) were added with compost charcoal III (Fe 2+ with Fe 3+ The molar ratio was 2.8:1, invasive biocompost: modified biochar = 5.2%: 2.1%), and the control was without compost charcoal, with 4 replicates. After the rice matured, the whole plants were collected.

[0189] (5) The iron film on the root surface was determined by extraction with sodium dithionite-trisodium citrate-sodium bicarbonate (DCB) method, and the iron content in the extract was determined by atomic absorption spectrometry.

[0190] 2. Results

[0191] Effects of invasive biocompost charcoal III on iron plaque on rice roots in arsenic-contaminated soils Fig.11 As shown in the figure, there are significant differences in the iron film content between different rice varieties (P < 0.05). The iron film content of Meixiangzhan No. 2 and Xiangyazhan, which are japonica rice, is significantly higher than that of other indica rice. Among indica rice, Huanghuazhan has the highest iron film content on the root surface, reaching 586.1g / kg, but it is still significantly lower than Meixiangzhan's 629.3g / kg and Xiangyazhan's 647.5g / kg. The application of compost charcoal has promoted the formation of iron film on the root surface of rice to a certain extent. Compared with the control, the iron film of each treatment increased by 5-12%, Meixiangzhan No. 2 increased the most (12.03%), and Yoshida Youhuazhan increased the least (5.83%).

[0192] Application Example 9 Effects of Invasive Biocompost Carbon III on Selenium Content in Rice Grains of Different Varieties in Arsenic-Contaminated Soil

[0193] 1. Methods

[0194] (1) Prepare optimized invasive biocompost charcoal III according to the conditions of the aforementioned Example 3.

[0195] (2) The 10 rice varieties tested were Huanghuazhan (Guangdong-approved rice 2005010), 19xiang (Guangdong-approved rice 20200065), Jinkesimiao 2 (Guangdong-approved rice 20220087), Meixiangzhan 2 (Guangdong-approved rice 2006009), Xiangyazhan (Guangdong-approved rice 2003044), Luyinzhan (Nationally-approved rice 20206125), Erguangxiangzhan (Guangdong-approved rice 20200069), Jitianyouhuazhan (Gan-approved rice 20180040), Jingliangyou 1212 (Nationally-approved rice 2016601), and Lujingzhan (Xiang-approved rice 20220034), all of which were local double-season rice varieties.

[0196] (3) Rice seeds of different varieties were transplanted by seedling raising. When the rice seedlings in the seedling trays grew to four leaves and one heart, they were transplanted. When transplanting, rice seedlings with the same growth were selected, two plants per pot, and 6 kg of test soil per pot. During the growth period of rice, the pot was kept at a water depth of 4 cm. The pot was flooded throughout the growth period, and no water was added one week before the rice harvest.

[0197] (4) All 10 rice varieties used in the experiment were set up as a control (CK) and a treatment (T). All treatments (T) were added with compost charcoal III (Fe 2+ with Fe 3+ The molar ratio was 2.8:1, invasive biocompost: modified biochar = 5.2%: 2.1%), and the control was without compost charcoal, with 4 replicates. After the rice matured, the whole plants were collected.

[0198] (5) Determination of selenium content in rice grains: The selenium content was determined by using a graphite furnace digester and an atomic fluorescence spectrophotometer.

[0199] 2. Results

[0200] Effects of invasive biocompost charcoal III on selenium content in rice grains of different varieties grown in arsenic-contaminated soils Fig.12 As shown in the figure, it can be seen that the selenium contents in the rice grains of Meixiangzhan No. 2 and Xiangyazhan are 0.03 mg / kg and 0.02 mg / kg respectively, and the selenium contents in the remaining rice grains are between 0.01 mg and 0.02 mg / kg.

Claims

1. A method for preparing invasive organism compost charcoal, characterized in that: The steps include: S1. drying and crushing the cleaned Mikania micrantha; washing the separated Pomacea canaliculata meat; S2. The raw materials prepared in step S1 are placed in a composting container according to a carbon-nitrogen ratio of 20 to 30:1, the moisture content is controlled at 55 to 65%, mixed, and evenly sprayed with 1.5 to 4.5 mg / kg of nano-selenium solution before composting. The composting days are 45 to 55 days to obtain invasive biological selenium-rich compost; S3. Place biochar powder in Fe 2+ with Fe 3+ In the mixed solution, the pH of the system is adjusted to 11-12, and then an aging treatment is performed, followed by suction filtration, drying, and grinding to prepare iron-modified biochar; the Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 1.9-2.9:1, and the pH is 4-5; S4. Mix the selenium-rich compost of the invasive organisms in step S2 and the iron-modified biochar in step S3 to prepare invasive organism compost charcoal; the mass ratio of the invasive organism compost to the modified biochar is: 0.7-6.5:0.5-6.

9.

2. The preparation method according to claim 1, characterized in that: The Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 1.9-2.3:1; the mass ratio of the invasive organism selenium-rich compost to the iron-modified biochar is 2.6-4.2:4.8-6.

9.

3. The preparation method according to claim 1, characterized in that: The Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 2.4-2.6:1; the mass ratio of the invasive biological selenium-rich compost to the iron-modified biochar is 0.7-2.5:2.5-4.

7.

4. The preparation method according to claim 1, characterized in that: The Fe 2+ with Fe 3+ Fe in mixed solution 2+ with Fe 3+ The molar ratio is 2.7-2.9:1; the mass ratio of the invasive biological selenium-rich compost to the iron-modified biochar is 4.3-6.5:0.5-2.

4.

5. The preparation method according to claim 1, characterized in that: The carbon-nitrogen ratio in step S2 is 21:

1.

6. The preparation method according to claim 1, characterized in that: The specific surface area of ​​the biochar powder in step S3 is 10.18 to 40.89 m 2 / g, and the pore size is 9.58~15.27nm.

7. Invasive organism compost charcoal prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the invasive organism compost charcoal according to claim 7 in passivating soil arsenic, improving the quality of arsenic-contaminated soil, and achieving low-carbon and selenium-enriched crops on arsenic-contaminated soil.

9. The use according to claim 8, characterized in that: The crop is rice.

10. The use according to claim 8, characterized in that: The arsenic content in arsenic-contaminated soil is 50-100 mg / kg.

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