A method for safe utilization of land reclamation

Abstract

The application discloses a kind of farmland repair safe utilization methods, including farmland repair and farmland safe utilization, specifically are as follows: (1) soil acidification conditioning: the contaminated farmland is ploughed, according to 800-1400kg / mu is applied organic fertilizer, then in the soil in agricultural product sowing before acidification conditioning agent is scattered, scattering amount is 1000-2000kg / hm 2 ; (2) micro-fertilizer regulation: during the growth period of agricultural products, microelement fertilizer is applied; (3) water regulation technology: during the key period of agricultural product growth, water regulation measures are adopted to maintain appropriate moisture in the soil; the acidification conditioning agent comprises 15-25 parts of humic acid, 4-10 parts of montmorillonite and 30-50 parts of modified coral sand. The application effectively realizes the effective repair and safe use of the contaminated farmland through the improvement of soil acidification conditioning and micro-fertilizer regulation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of safe use of contaminated farmland, and particularly relates to a method for safe use of farmland remediation. BACKGROUND

[0002] Farmland is a natural resource for human survival. Influenced by soil parent material and human production activities, heavy metals in local farmland exceed the standard, affecting ecological safety and human health. Safe use of contaminated farmland has always been valued. The safe use of contaminated farmland is based on the actual situation of the local region, the main pollutant characteristics of the village from the plot, and the main principles of economic efficiency and easy promotion. The safe use area adopts treatment measures according to local conditions, and at the same time, strict supervision and management of the control area are strengthened. The treatment scheme should clearly define the task objectives, implement comprehensive measures, and focus on solving difficult problems. Thus, a mature low-cost, effective and easy-to-promote comprehensive prevention and control technology mode for contaminated farmland is formed. Safe use of contaminated farmland and realization of safe production of crops are important measures to protect food safety and human health. It is an important guarantee for the green and high-quality development of agriculture and the protection of food safety to consolidate and improve the level of safe use of contaminated farmland.

[0003] In the existing farmland remediation, soil acidification and soil passivation conditioning are generally required. However, the existing technology does not consider the coordination and appropriate range between soil pH value and soil heavy metal content, and cannot simultaneously consider soil acidification and soil conditioning, resulting in poor soil remediation effect.

[0004] When the remediated farmland is used safely, micro-fertilizer regulation is generally required. The existing micro-fertilizer is generally directly applied, resulting in uneven fertilization effect. Some micro-fertilizers are surface treated, but new organic synthetic raw materials are introduced, which lacks green environmental protection and easily causes further soil pollution. The micro-fertilizer after surface treatment is not easily absorbed due to the limitation of surface materials.

[0005] In summary, how to provide a method for safe use of farmland remediation by improving soil acidification conditioning and micro-fertilizer regulation to realize effective remediation and safe use of contaminated farmland is a problem to be solved at present. SUMMARY

[0006] The present application aims to provide a method for safe use of farmland remediation, which uses acidification conditioning agent during farmland remediation. Not only can the acid soil be remediated, but also the biological availability of heavy metals in the soil can be reduced by adsorbing the heavy metals, the soil can be conditioned, and the raw materials used are mild to the environment. In the present application, the microelement fertilizer is treated before being applied during micro-fertilizer regulation, which can ensure the uniformity and dispersibility of the fertilizer and maintain the effectiveness of the fertilizer without being easily deteriorated. In addition, the present application also sprays a leaf surface control agent to improve the absorption of selenium and iron by crops and reduce the absorption of cadmium and other heavy metals.

[0007] The first object of the present application is to provide a method for safe utilization of cultivated land remediation.

[0008] The object of the present application is achieved by a method for safe utilization of cultivated land remediation, specifically comprising the following steps:

[0009] (I) Cultivated land remediation

[0010] (1) Soil acidification conditioning: the cultivated land is ploughed, and 800-1400 kg / mu of organic fertilizer (which is generally alkaline and has an acid regulating effect) is applied, and then an acidification conditioner is applied in the soil at least one week before the planting of agricultural products, with an application amount of 1000-2000 kg / hm 2 , to adjust the soil pH and condition the soil, and reduce the bioavailability of heavy metals in the soil through adsorption, oxidation-reduction or precipitation, etc.

[0011] (II) Safe utilization of cultivated land

[0012] (2) Micro-fertilizer regulation: applying trace element fertilizer during the growth period of agricultural products can effectively reduce the absorption of heavy metals by rice.

[0013] (3) Water regulation technology: adopting water regulation measures to maintain appropriate soil moisture during the critical growth period of agricultural products; the soil environment can present a strong reducing state, and the soil pH increases significantly, among which the effective cadmium is adsorbed by dissolved organic matter, etc., and on the other hand, cadmium sulfide precipitates, and the bioavailability is greatly reduced.

[0014] (4) Leaf surface control: spraying leaf surface control agent during the critical growth period; effectively controlling the transport of heavy metals to the grain, and ultimately reducing the risk of grain heavy metal exceeding the standard.

[0015] (5) Adjustment of planting structure: this measure is suitable for strictly controlled cultivated land, and in severely polluted areas, non-food crops such as cotton, hemp, seedlings, flowers, etc. are adjusted to be planted. The adjustment of planting structure can realize safe production, and also can bring normal income to farmers. At present, the adjustment of planting structure has been widely popularized and applied in various places across the country, but the adjustment of planting structure also has the problems of changing the planting habits of farmers and objectively reducing the yield of grain.

[0016] The acidification conditioner comprises 15-25 parts of humic acid, 4-10 parts of montmorillonite and 30-50 parts of modified coral sand, and the acidification conditioner is prepared by directly mixing the above three raw materials, and the preparation of the modified coral sand comprises the following steps:

[0017] S1, crushing the husk into 100-200 mesh husk powder, then soaking in saturated lime water for 1-3 h, then drying the water, and adding sodium bicarbonate powder to obtain a mixed powder;

[0018] S2, after ultrasonic cleaning and drying the coral sand, the mixed powder obtained in step S1 is mixed evenly, then humidified, and then carbonized at 450-550 DEG C for 3-5h, so that the husk powder is carbonized, and cooled to room temperature by ventilation;

[0019] S3, the product obtained in step S2 is immersed in an organic solvent of citric acid ester for 20-40min, and then the solvent is evaporated to obtain the modified coral sand.

[0020] Further, the mass ratio of the citric acid ester to the organic solvent is 1: (5-20), the citric acid ester is triethanolamine citrate, and the organic solvent is ethanol or acetone.

[0021] Further, the mass ratio of the coral sand, the husk, the sodium bicarbonate, the saturated lime water and the citric acid ester is 1: (0.1-0.3): (0.005-0.01): (3-10): (0.01-0.05), and the amount of water for humidification before carbonization is 3-7% of the total mass of the coral sand and the mixed powder.

[0022] Further, the trace element fertilizer is one or more of iron fertilizer (FeSO4•H2O 5-10kg / acre), selenium fertilizer (Na2SeO3 50-100g / acre), zinc fertilizer (ZnSO4•7H2O 3-5kg / acre) or silicon fertilizer (Na2.SiO3 4-5kg / acre).

[0023] The second object of the application is to provide a treatment method of the trace element fertilizer in the method for safe utilization of the cultivated land repair.

[0024] The trace element fertilizer is treated as follows before application:

[0025] The trace element fertilizer is stirred (300-500r / min) with starch, water, antioxidant and dispersant, then extruded and granulated, passed through a 60-80 mesh sieve, dried, and the prepared granules are soaked in 5-10 times the amount of salicylic acid-ethanol solution for 30-60min, then filtered and dried to obtain the treated trace element fertilizer; the antioxidant is a gallate compound, and the dispersant is an alkyl amine compound.

[0026] Further, the gallate compound is octadecyl gallate, and the alkyl amine compound is octadecyl dimethylamine dimethyl silane.

[0027] Further, the mass ratio of the microelement fertilizer, starch, water, antioxidant and dispersant is 1: (1-1.4): (0.06-0.09): (0.04-0.08): (0.02-0.05), and the mass ratio of salicylic acid and ethanol in the salicylic acid-ethanol solution is 1: (4-6).

[0028] A third object of the present application is to provide a foliar control agent for use in the method for safe utilization of the cultivated land repair.

[0029] The foliar control agent comprises 20-40 parts of a silicon-containing compound, 0.1-0.2 parts of a selenium-containing compound, 8-15 parts of an iron-containing compound, 8-20 parts of a coating agent, 0.4-0.8 parts of a thickening agent comprising magnesium aluminum silicate and a saccharide compound in a mass ratio of 1: (0.2-0.5), and 30-50 parts of distilled water, and the coating agent comprises a higher aliphatic alcohol and an amino acid ester in a mass ratio of 1: (0.06-0.2).

[0030] The preparation method of the foliar control agent comprises the following steps:

[0031] The distilled water is taken according to the formula at room temperature, and the silicon-containing compound, the selenium-containing compound and the iron-containing compound are sequentially added, stirred (300-500 r / min) for 10-20 min, then the thickening agent is added, stirred (600-800 r / min) for 15-30 min, then heated to 70-80 DEG C, the coating agent is added and stirred (500-700 r / min) for 40-60 min, and the foliar control agent is obtained.

[0032] Further, the saccharide compound is trehalose 6,6'-dibehenate, and the amino acid ester is glycine n-octyl ester hydrochloride.

[0033] Further, the silicon-containing compound is potassium silicate or sodium silicate, the selenium-containing compound is sodium selenate or sodium selenite, the iron-containing compound is ferrous sulfate or ferric sulfate, and the higher aliphatic alcohol is a C15-C20 aliphatic alcohol.

[0034] The present application has the following beneficial effects:

[0035] 1. The acidification conditioner is used in the cultivated land repair, the modified coral sand is mainly coral sand, the alkaline substance in the coral sand itself can increase the pH, the acidification effect is improved by introducing the alkali-containing husk in the modified coral sand, the soil heavy metal content is regulated by the multiple pores of the coral sand and the adsorption of the heavy metal, and the raw materials are mild to the environment.

[0036] 2、Although the pores of the coral sand are many, but the pores are large and uneven, it is difficult to stabilize the adsorption of heavy metal ions, therefore, the present application modifies the coral sand, the husk is crushed and introduced into the large pores of the coral sand, then carbonized, the husk after carbonization forms multiple three-dimensional pore structure in the coral sand, improves the adsorption stability of the modified coral sand to heavy metal ions, and is not easy to desorb, therefore, the modified coral sand of the present application has good soil acid adjusting and passivation effect. In addition, the mixed powder contains sodium bicarbonate, and before carbonization in step S2, it is also humidified, so that the sodium bicarbonate is decomposed to produce carbon dioxide during the carbonization process, and the acidic water vapor formed together with the evaporated water vapor can form pores inside the coral sand (main component is calcium carbonate), further promoting the combination of the coral sand and the carbonized husk, and improving the adsorption performance of the modified coral sand.

[0037] 3、The present application also introduces citric acid ester when preparing modified coral sand, which contains carboxyl groups that can chelate heavy metal ions, further improving the soil passivation effect.

[0038] 4、Because the alkalinity of lime water is too strong, it can easily cause the lack of soil nutrients and uneven acid adjustment, therefore, the citric acid ester of the present application further selects triethanolamine citric acid ester, when the acidifying conditioner is applied to the soil, the modified coral sand absorbs the water in the soil, so that the triethanolamine citric acid ester slowly undergoes alkaline hydrolysis under the condition of strong alkaline lime water, gradually forming citrate and triethanolamine, which can perform mild acid adjustment and improve the adverse effects of strong alkali lime water without affecting the soil.

[0039] 5、The citrate and triethanolamine generated by the alkaline hydrolysis of triethanolamine citric acid ester both have chelation effect on heavy metal ions, therefore, during the process of land remediation, according to the changes of pH value and effective heavy metal ion content in the soil, citrate and triethanolamine can automatically select to play the role of acid adjustment or chelation of heavy metal ions, so that the pH value and heavy metal ion content of the soil are adjusted within the appropriate range.

[0040] 6、The present application mixes and disperses the trace element fertilizer with starch, and then granulates, which can ensure the uniformity and dispersity of the application of micro-fertilizer, and also adds an antioxidant, which can ensure that the elements in the trace element fertilizer (especially iron fertilizer) are not oxidized and deteriorated, and maintain the effectiveness of the fertilizer; in addition, after the micro-fertilizer is granulated, it is soaked in a salicylic acid-ethanol solution to remove the dispersant molecules and the alkyl long chain structure in the antioxidant gallic acid ester, so that the dispersant and antioxidant also play a pore-forming role, forming porous micro-fertilizer particles, improving the dispersity and absorption effect of the micro-fertilizer in the soil.

[0041] 7. In the treatment of micro-fertilizers, the present invention uses gallic acid esters as antioxidants, which can enhance the antioxidant effect. The present invention further selects octadecyl gallate, which, while possessing antioxidant properties, also has the following functions: (1) it adheres to starch and fertilizer to act as a bridge, improving the dispersion effect; (2) after the micro-fertilizer is granulated, it is soaked in a salicylic acid-ethanol solution, which causes the octadecyl gallate bridging between starch and micro-fertilizer to undergo acidic hydrolysis to generate gallic acid and octadecyl alcohol, which form pores in the micro-fertilizer particles to play a pore-forming role. The octadecyl alcohol dissolves and diffuses into the solution, while the gallic acid remains in the pores to play an antioxidant role. That is, the antioxidant components in the porous micro-fertilizer particles obtained by the present invention are distributed in the pores, which can effectively prevent the air entering the pores from oxidizing the fertilizer and fully exert its antioxidant effect.

[0042] 8. In the treatment of micro-fertilizers, this invention uses alkylamine compounds as dispersants, which have good dispersing effects. This invention further selects octadecyl dimethylamine dimethylsilane, which, while having a dispersing effect, can also diffuse and dissolve from micro-fertilizer particles into a salicylic acid-ethanol solution, thereby exerting a pore-forming effect. Because the nonpolar end of octadecyl dimethylamine dimethylsilane is tightly bonded to the long alkyl chain of octadecyl gallate, the hydrolysis of octadecyl gallate to release the long alkyl chain also promotes the diffusion of octadecyl dimethylamine dimethylsilane. Furthermore, the lubricating properties of the silane groups in octadecyl dimethylamine dimethylsilane and the basicity of dimethylamine also promote its diffusion and dissolution in the salicylic acid-ethanol solution, fully exerting its pore-forming effect.

[0043] 9. In the porous micro-fertilizer granules of the present invention, the natural organic acid gallic acid is the real antioxidant. Its organic compound dispersant is removed after playing the role of material dispersion through pore formation, so that the porous micro-fertilizer granules obtained by the present invention are green and environmentally friendly and suitable for safe use in arable land.

[0044] 10. Because the pH of the cultivated land increases after acidification, the effectiveness of iron fertilizer in the micronutrient fertilizer in the soil is reduced, affecting the absorption of iron fertilizer. The addition of iron fertilizer, to a certain extent, lowers the pH of the soil, reducing the effectiveness of the micronutrient selenium and increasing the effectiveness of the heavy metal cadmium. Therefore, this invention requires the application of foliar inhibitors containing selenium and iron compounds to improve the absorption of selenium and iron by crops and reduce the absorption of cadmium and other heavy metals.

[0045] 11、The foliar control agent of the present application contains a thickening agent composed of magnesium aluminum silicate and saccharide compounds, so that the silicon-containing, selenium-containing and iron-containing compounds can be uniformly suspended and dispersed, and the absorption of silicon, selenium and iron by the leaf surface is promoted. The saccharide compound of the present application is further selected as trehalose 6,6'-dibehenate, which not only has a thickening effect, but also has the following effects: (1) surface activity effect, on the one hand, adhering to the hydrophobic magnesium aluminum silicate surface to improve its hydrophilicity, on the other hand, enhancing the wetting, dispersion and adhesion of the silicon-containing, selenium-containing and iron-containing compounds on the leaf surface; (2) biological activity effect, due to the presence of trehalose structure, the biological activity of the silicon-containing, selenium-containing and iron-containing compounds is enhanced, so that they are more easily absorbed and utilized by the leaf surface; (3) anti-slip effect, because the presence of magnesium aluminum silicate affects the adhesion effect of the foliar control agent on the leaf surface, trehalose 6,6'-dibehenate easily embeds into the network structure formed by magnesium aluminum silicate in water, and plays an anti-slip role.

[0046] 12、The foliar control agent of the present application contains a coating agent composed of a higher fatty alcohol and an amino acid ester, which can form a stable protective layer on the leaf surface, reduce water loss and lock the effective ingredients (silicon-containing, selenium-containing and iron-containing compounds) in the foliar control agent. The amino acid ester of the present application is further selected as glycine n-octyl ester hydrochloride, the non-polar end of which combines with the higher fatty alcohol to form a protective layer, and the other end of the glycine salt structure can absorb carbon dioxide in the air, on the one hand, forming air holes in the protective layer with air permeability, avoiding the influence on the respiration of the growing leaf surface, on the other hand, storing a certain amount of carbon dioxide in the foliar control agent, further promoting the growth of the leaf surface.

[0047] 13、The trehalose 6,6'-dibehenate in the thickening agent of the present application, on the one hand, combines with magnesium aluminum silicate to play a thickening and stabilizing role, on the other hand, can also combine with the protective layer formed by the higher fatty alcohol and glycine n-octyl ester hydrochloride to increase the thickness and stability of the protective layer, and make the protective layer tightly combined with the thickening system, prevent the protective layer from separating from the effective ingredients of the foliar control agent to form gaps, and affect the stability and protection effect of the protective layer. DETAILED DESCRIPTION

[0048] The present application will be further described below in conjunction with examples. Obviously, the described examples are only a part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by a person of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0049] Now taking a polluted farmland in Ganzhou, Jiangxi as an experimental area, the total area is 46 mu, which is divided into 23 experimental areas on average, to implement the following examples 1-5 and comparative examples 1-18 of farmland remediation and safe utilization scheme, and the present application specifically takes rice planting as an example.

[0050] Embodiment 1

[0051] The embodiment provides a method for repairing and reusing ion-type rare earth tailings, and comprises the following steps:

[0052] (I) Cultivated land repair

[0053] (1) Soil acidification conditioning: the contaminated paddy field is ploughed, 800-1400 kg / mu of organic fertilizer is applied, and then the acidification conditioner is applied in the soil at least one week before rice transplanting or direct seeding, with an application amount of 1000 kg / hm 2 , to adjust the soil pH and condition the soil, reduce the bioavailability of heavy metals in the soil by adsorption, oxidation-reduction or precipitation, etc., so that the heavy metals cannot be absorbed by rice, and the application frequency is 1 time / year, which can be carried out manually or mechanically, and the subsequent monitoring is strengthened.

[0054] (II) Safe use of cultivated land

[0055] (2) Microelement regulation: applying trace element fertilizer at the tillering stage of rice can effectively reduce the absorption of heavy metals by rice; the trace element fertilizer includes iron fertilizer (FeSO4•H2O 5-10 kg / mu) and zinc fertilizer (ZnSO4•7H2O 3-5 kg / mu).

[0056] (3) Water regulation technology: appropriate soil moisture is maintained by water regulation measures at the key growth stages of rice (such as the tillering stage and the heading and filling stage); the soil environment can present a strong reducing state, and the soil pH increases significantly, among which the effective cadmium is adsorbed by dissolved organic matter, etc., on the one hand, and forms cadmium sulfide precipitate on the other hand, and the bioavailability is greatly reduced. The water regulation is specifically to delay the field drying for 7 days after the seedlings are sufficient at the tillering stage of rice, and then keep the soil flooded for 10 days before the harvesting period after the field drying and rewatering. The flooding method can be to pad soil at the farmland drainage outlet, with a flooding depth of 3-5 cm, and the field cannot be dried during the period.

[0057] The acidification conditioner comprises 15 parts of humic acid, 4 parts of montmorillonite and 30 parts of modified coral sand, and the acidification conditioner is prepared by directly mixing the three raw materials. The preparation of the modified coral sand comprises the following steps:

[0058] S1, crushing the rice husk into 100-mesh rice husk powder, then soaking in saturated lime water for 1 h, then drying, and adding sodium bicarbonate powder to obtain a mixed powder;

[0059] S2, uniformly mixing the ultrasonically cleaned and dried coral sand with the mixed powder obtained in step S1, then humidifying (the water amount for humidifying is 3% of the total mass of the coral sand and the mixed powder), and then carbonizing at 450°C for 5 h to carbonize the rice husk powder, and cooling to room temperature.

[0060] S3, the product obtained in step S2 is soaked in an ethanol solution of triethanolamine citrate for 20 min, and then the solvent is evaporated to obtain the modified coral sand, the mass ratio of triethanolamine citrate to ethanol being 1:5.

[0061] The mass ratio of the coral sand, the husk, the sodium bicarbonate, the saturated lime water and the citrate is 1:0.1:0.005:3:0.01.

[0062] Example 2

[0063] On the basis of example 1, the present example provides a method for repairing and reusing ion-type rare earth tailings, in which the trace element fertilizer is applied after the following treatment:

[0064] The trace element fertilizer, starch, water, antioxidant (octadecyl gallate), dispersant (octadecyl dimethylamine dimethyl silane) are stirred (300 r / min) uniformly according to a mass ratio of 1:1:0.06:0.04:0.02, and then extruded and granulated, passed through a 60-mesh sieve, dried, and the prepared granules are soaked in 5 times the amount of a salicylic acid-ethanol solution (the mass ratio of salicylic acid to ethanol being 1:4) for 30 min, and then filtered and dried to obtain the treated trace element fertilizer.

[0065] The rest is the same as example 1.

[0066] Example 3

[0067] On the basis of example 2, the present example provides a method for repairing and reusing ion-type rare earth tailings, in which the safe use of arable land further includes foliar control measures:

[0068] The foliar control agent is sprayed at a critical growth stage, the application amount being 200 mL / acre, and the foliar spraying is performed after dilution by 50 times. It can effectively control the transport of heavy metals to the grain, and ultimately reduce the risk of grain heavy metal exceeding the standard. The foliar control technology has the characteristics of low cost, easy operation and large-area application.

[0069] The foliar control agent includes 20 parts of sodium silicate, 0.1 parts of sodium selenite, 8 parts of ferrous sulfate, 8 parts of coating agent, 0.4 parts of thickening agent and 30 parts of distilled water, the thickening agent including magnesium aluminum silicate and saccharide compound (trehalose 6,6'-dibehenate) in a mass ratio of 1:0.2, and the coating agent including C15 fatty alcohol and amino acid ester (glycine n-octyl ester hydrochloride) in a mass ratio of 1:0.06.

[0070] The preparation method of the foliar control agent includes the following steps:

[0071] At normal temperature, distilled water is taken according to the formula, sodium silicate, sodium selenite and ferrous sulfate are added in sequence, stirred (300 r / min) for 20 min, then a thickening agent is added, stirred (600 r / min) for 30 min, then heated to 70 DEG C, a coating agent is added and stirred (500 r / min) for 60 min, and the foliar control agent is obtained.

[0072] The rest is the same as example 2.

[0073] Example 4

[0074] The embodiment provides a method for safe utilization of cultivated land repair, and specifically comprises cultivated land repair (soil acidification conditioning) and cultivated land safe utilization (micro-fertilizer regulation, water regulation, and foliar control), the application amount of the acidification conditioner in the soil acidification conditioning process is 1500 kg / hm 2 ,

[0075] The acidification conditioner comprises 20 parts of humic acid, 7 parts of montmorillonite and 40 parts of modified coral sand, and the acidification conditioner is directly prepared by mixing the three raw materials, and the preparation of the modified coral sand comprises the following steps.

[0076] S1, the husk is crushed into 140 mesh husk powder, then soaked in saturated limewater for 2h, then dried, and mixed with sodium bicarbonate powder to obtain a mixed powder;

[0077] S2, the coral sand is ultrasonically cleaned, dried, and then mixed with the mixed powder obtained in step S1, then humidified (the amount of water added is 5% of the total mass of the coral sand and the mixed powder), then carbonized at 500 DEG C for 4h, so that the husk powder is carbonized, and cooled to room temperature in a ventilated manner;

[0078] S3, the product obtained in step S2 is soaked in an ethanol solution of triethanolamine citrate ester for 30 min, and then evaporated to dryness to obtain the modified coral sand, and the mass ratio of triethanolamine citrate ester to ethanol is 1:12.

[0079] Among them, the mass ratio of coral sand, husk, sodium bicarbonate, saturated limewater, citrate ester is 1:0.2:0.007:6:0.03.

[0080] The microelement fertilizer is applied after the following treatment:

[0081] The trace element fertilizer is stirred (400 r / min) uniformly with starch, water, antioxidant (octadecyl gallate), dispersing agent (octadecyl dimethylamine dimethyl silane) according to a mass ratio of 1:1.2:0.075:0.06:0.035, and then is extruded and granulated, sieved through a 70-mesh screen, dried, and soaked in 8 times the amount of a salicylic acid-ethanol solution (a mass ratio of salicylic acid to ethanol is 1:5) for 45 min, and then filtered and dried to obtain the treated trace element fertilizer.

[0082] The application amount of the foliar resistance control agent is 250 mL / acre, and the foliar resistance control agent comprises 30 parts of sodium silicate, 0.15 parts of sodium selenite, 12 parts of ferrous sulfate, 14 parts of coating agent, 0.6 parts of thickening agent and 40 parts of distilled water, wherein the thickening agent comprises magnesium aluminum silicate and saccharide compound (trehalose 6,6'-dibehenate) at a mass ratio of 1:0.35, and the coating agent comprises C18 fatty alcohol and amino acid ester (glycine n-octyl ester hydrochloride) at a mass ratio of 1:0.13.

[0083] The preparation method of the foliar resistance control agent comprises the following steps:

[0084] The distilled water is taken according to the formula at room temperature, and the sodium silicate, sodium selenite and ferrous sulfate are sequentially added and stirred (400 r / min) for 15 min, and then the thickening agent is added and stirred (700 r / min) for 24 min, and then the temperature is increased to 75 DEG C, the coating agent is added and stirred (600 r / min) for 50 min, and the foliar resistance control agent is obtained.

[0085] The rest is the same as in Example 3.

[0086] Example 5

[0087] The present embodiment provides a method for safe utilization of cultivated land repair, specifically including cultivated land repair (soil acidification conditioning) and safe utilization of cultivated land (micro-fertilizer regulation, water regulation, foliar resistance control), and the application amount of the acidification conditioner in the soil acidification conditioning process is 2000 kg / hm 2 ,

[0088] The acidification conditioner comprises 25 parts of humic acid, 10 parts of montmorillonite and 50 parts of modified coral sand, and the acidification conditioner is directly prepared by mixing the above three raw materials, and the preparation of the modified coral sand comprises the following steps:

[0089] S1, the husk is crushed into 200-mesh husk powder, and then soaked in saturated limewater for 3 h, and then the water is dried, and the mixed powder is obtained by adding sodium bicarbonate powder;

[0090] S2, after ultrasonic cleaning and drying the coral sand, mix the mixed powder obtained in step S1 evenly, then humidify (the amount of water added is 7% of the total mass of the coral sand and the mixed powder), and then carbonize at 550℃ for 3h, so that the millet shell powder is carbonized, and then cooled to room temperature;

[0091] S3, the product obtained in step S2 is soaked in a three ethanol amine citrate acetone solution for 40min, and then the solvent is evaporated to obtain the modified coral sand, the mass ratio of three ethanol amine citrate to acetone is 1:20.

[0092] The mass ratio of the coral sand, the millet shell, the sodium bicarbonate, the saturated lime water and the citrate is 1:0.3:0.01:10:0.01.

[0093] The trace element fertilizer is applied after the following treatment:

[0094] The trace element fertilizer, the starch, the water, the antioxidant (octadecyl gallate), and the dispersant (octadecyl dimethylamine dimethyl silane) are stirred (500r / min) according to the mass ratio of 1:1.4:0.09:0.08:0.05, and then extruded and granulated, and then sieved through an 80 mesh sieve, and then dried, and then the prepared granules are soaked in 10 times the amount of a salicylic acid-ethanol solution (the mass ratio of salicylic acid to ethanol is 1:6) for 60min, and then filtered and dried to obtain the treated trace element fertilizer.

[0095] The application amount of the foliar resistance control agent is 300mL / acre, and the foliar resistance control agent comprises 40 parts of potassium silicate, 0.2 parts of sodium selenate, 15 parts of ferric sulfate, 20 parts of a coating agent, 0.8 parts of a thickening agent, and 50 parts of distilled water, the thickening agent comprises magnesium aluminum silicate and a saccharide compound (trehalose 6,6'-dibehenate) in a mass ratio of 1:0.5, and the coating agent comprises a C20 fatty alcohol and an amino acid ester (glycine n-octyl ester hydrochloride) in a mass ratio of 1:0.2.

[0096] The preparation method of the foliar resistance control agent comprises the following steps:

[0097] The distilled water is taken according to the formula at room temperature, and then the potassium silicate, the sodium selenate and the ferric sulfate are added in sequence, and stirred (500r / min) for 10min, and then the thickening agent is added, and stirred (800r / min) for 15min, and then the temperature is increased to 80℃, and the coating agent is added and stirred (700r / min) for 40min to obtain the foliar resistance control agent.

[0098] The rest is the same as in example 3.

[0099] Comparative example 1

[0100] The difference between this comparative example and example 1 is that the acidification conditioner does not contain modified coral sand.

[0101] Comparative Example 2

[0102] The difference between this comparative example and Example 1 is that the modified coral sand in the acidifying conditioner is replaced by common coral sand.

[0103] Comparative Example 3

[0104] The difference between this comparative example and Example 1 is that sodium bicarbonate is not added in the preparation step S1 of the modified coral sand.

[0105] Comparative Example 4

[0106] The difference between this comparative example and Example 1 is that carbonization is not performed in the preparation step S2 of the modified coral sand, and at this time, step S2 is: after ultrasonic cleaning and drying of the coral sand, the mixed powder obtained in step S1 is mixed uniformly.

[0107] Comparative Example 5

[0108] The difference between this comparative example and Example 1 is that the preparation of the modified coral sand does not include step S3.

[0109] Comparative Example 6

[0110] The difference between this comparative example and Example 1 is that triethanolamine citrate is replaced by diethyl citrate in the preparation step S3 of the modified coral sand.

[0111] Comparative Example 7

[0112] The difference between this comparative example and Example 2 is that the antioxidant octadecyl gallate is not used in the treatment method of the trace element fertilizer.

[0113] Comparative Example 8

[0114] The difference between this comparative example and Example 2 is that the dispersant octadecyl dimethylamine dimethyl silane is not used in the treatment method of the trace element fertilizer.

[0115] Comparative Example 9

[0116] The difference between this comparative example and Example 2 is that the trace element fertilizer is not soaked in the salicylic acid-ethanol solution in the treatment method of the trace element fertilizer.

[0117] Comparative Example 10

[0118] The difference between this comparative example and Example 2 is that the antioxidant octadecyl gallate is replaced by gallic acid in the treatment method of the trace element fertilizer.

[0119] Comparative Example 11

[0120] The difference between this comparative example and Example 2 is that the antioxidant octadecyl gallate is replaced by octyl gallate in the treatment method of the trace element fertilizer.

[0121] Comparative Example 12

[0122] The difference between the present comparative example and Example 2 is that the dispersant octadecyl dimethylamine dimethyl silane in the treatment method of the microelement fertilizer is replaced by octadecyl amine.

[0123] Comparative Example 13

[0124] The difference between the present comparative example and Example 3 is that the thickening agent in the foliar control agent is magnesium aluminum silicate.

[0125] Comparative Example 14

[0126] The difference between the present comparative example and Example 3 is that the thickening agent in the foliar control agent is trehalose 6,6'-dibehenate.

[0127] Comparative Example 15

[0128] The difference between the present comparative example and Example 3 is that the coating agent is not contained in the foliar control agent.

[0129] Comparative Example 16

[0130] The difference between the present comparative example and Example 3 is that the coating agent in the foliar control agent is C15 fatty alcohol.

[0131] Comparative Example 17

[0132] The difference between the present comparative example and Example 3 is that the coating agent in the foliar control agent is glycine n-octyl ester hydrochloride.

[0133] Comparative Example 18

[0134] The difference between the present comparative example and Example 3 is that the glycine n-octyl ester hydrochloride in the foliar control agent is replaced by L-serine methyl ester hydrochloride.

[0135] I. Cultivated land repair effect of the present application

[0136] The contaminated cultivated land (paddy field) experimental area is repaired according to the method of Example 1, 4-5 and Comparative Examples 1-6 of the present application, and various parameters before and after repair are obtained, and the results are shown in Table 1 below.

[0137] Table 1

[0138]

[0139] As can be seen from Table 1, the repair effect of the cultivated land of the present application is very obvious, and the pH of the cultivated land of Examples 1, 4 and 5 is increased to about neutral, and the heavy metal content is far below the lower limit value of the national standard.

[0140] Compared with Example 1, the composition of the acidification conditioner and the preparation method of the modified coral sand are changed in Comparative Examples 1-6, and the pH increasing effect is reduced, and the heavy metal treatment effect is also poor.

[0141] Secondly, the growth of rice planted in the repaired farmland

[0142] The contaminated farmland (paddy field) experimental area is repaired according to the method of Examples 1-5 and Comparative Examples 1-18 of the present application, and rice is planted in the repaired farmland, and the yield and nutritional quality of the rice are detected, and the results are shown in Tables 2 and 3 below.

[0143] Table 2 Yield (kg / acre)

[0144]

[0145] Table 3 Nutritional quality of rice

[0146]

[0147] As can be seen from Tables 2 and 3, the yield of rice planted in Examples 1-5 of the present application is more than 1000 kg / acre, especially the yield of Examples 3-5 is more than 1500 kg / acre, and the nutritional components of the rice are high, and the yield and quality are both excellent.

[0148] Compared with Example 1, the composition of the acidification conditioner and the preparation method of the modified coral sand are changed in Comparative Examples 1-6, and the yield of rice is significantly reduced. Compared with Example 2, the treatment method of the trace element fertilizer is changed in Comparative Examples 7-12; compared with Example 3, the raw material composition of the leaf surface control agent is changed in Comparative Examples 13-18; and the yield and nutritional quality of rice of Comparative Examples 7-18 are reduced.

[0149] Thirdly, the content of heavy metals in rice planted

[0150] Rice is planted on the repaired farmland according to the method of Examples 1-5 and Comparative Examples 7-18 of the present application, and the content of heavy metals cadmium and lead in rice is detected, and the results are shown in Table 4 below.

[0151] Table 4 Content of heavy metals in rice (mg / kg)

[0152]

[0153] As can be seen from Table 4, the heavy metal content in the rice of the rice planted in Examples 1-5 of the present application all meets the provisions in the National Food Safety Standard Limits of Contaminants in Foods (GB 2762-2012), satisfies the food safety requirements, and indicates that the cultivated land remediation and safe utilization method of the present application is effective. Especially, the lead content in Examples 3-5 is 0.006-0.007 mg / kg, the cadmium content is 0.021-0.025 mg / kg, and the heavy metal residue is low.

[0154] Compared with Example 2, the treatment method of the trace element fertilizer is changed in Comparative Examples 7-12; compared with Example 3, the raw material composition of the foliar control agent is changed in Comparative Examples 13-18; the lead and cadmium residues in the rice are increased, and the safety is reduced.

[0155] It should be noted that the above only describes specific embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for the safe utilization of restored arable land, comprising arable land restoration and safe utilization of arable land, characterized in that: Specifically, the following steps are included: (I) Farmland Restoration (1) Soil acidification treatment: The polluted farmland is prepared and plowed, and organic fertilizer is applied at a rate of 800-1400 kg / mu. Then, before rice sowing, an acidification conditioner is applied to the soil at a rate of 1000-2000 kg / hm. 2 ; The acidification conditioner comprises 15-25 parts humic acid, 4-10 parts montmorillonite, and 30-50 parts modified coral sand. The preparation of the modified coral sand includes the following steps: S1. Crush the rice husks into 100-200 mesh rice husk powder, then soak them in saturated lime water for 1-3 hours, then dry them and add sodium bicarbonate powder to obtain a mixed powder. S2. After ultrasonic cleaning and drying of the coral sand, mix it evenly with the mixed powder obtained in step S1, then humidify it, and then carbonize it at 450-550℃ for 3-5 hours, and then cool it to room temperature through ventilation. S3. Soak the product obtained in step S2 in the organic solvent of citrate ester for 20-40 minutes, and then evaporate the solvent to obtain the modified coral sand. (II) Safe use of arable land (2) Micronutrient regulation: Apply micronutrient fertilizers during the tillering stage of rice; The micronutrient fertilizer is treated as follows before application: Micronutrient fertilizer is mixed evenly with starch, antioxidant, and dispersant, then extruded and granulated, sieved, and dried. The resulting granules are soaked in a salicylic acid-ethanol solution for 30-60 minutes, then filtered and dried to obtain the processed micronutrient fertilizer. The antioxidant is a gallic acid ester compound, and the dispersant is an alkylamine compound. (3) Water regulation: During the peak tillering and heading and grain filling stages of rice, water regulation measures are adopted to maintain appropriate soil moisture. Specifically, water regulation is carried out by delaying the drying of the field by 7 days after the rice seedlings have fully emerged during the tillering stage. After the field is dried and re-watered, it is kept submerged for 10 days before the harvest. During this period, the field should not be dried or dry. (4) Foliar inhibition: Spray foliar inhibition agents during the critical growth period; The leaf surface inhibition agent comprises 20-40 parts of silicon-containing compound, 0.1-0.2 parts of selenium-containing compound, 8-15 parts of iron-containing compound, 8-20 parts of coating agent, 0.4-0.8 parts of thickener, and 30-50 parts of distilled water. The thickener comprises magnesium aluminum silicate and sugar compound in a mass ratio of 1:(0.2-0.5), and the coating agent comprises higher fatty alcohol and amino acid ester in a mass ratio of 1:(0.06-0.2). The preparation method of the leaf surface inhibition agent includes the following steps: At room temperature, take distilled water according to the formula, add silicon-containing compound, selenium-containing compound and iron-containing compound in sequence, stir for 10-20 minutes, then add thickener, stir for 15-30 minutes, then heat to 70-80℃, add coating agent and stir for 40-60 minutes to obtain the leaf surface control agent.

2. The method for safe utilization of restored arable land according to claim 1, characterized in that: The mass ratio of the citrate ester to the organic solvent is 1:(5-20), the citrate ester is triethanolamine citrate ester, and the organic solvent is ethanol or acetone.

3. The method for safe utilization of restored arable land according to claim 1, characterized in that: The mass ratio of coral sand, rice husks, sodium bicarbonate, saturated lime water, and citrate is 1:(0.1-0.3):(0.005-0.01):(3-10):(0.01-0.05), and the amount of water added before carbonization is 3-7% of the total mass of coral sand and mixed powder.

4. The method for safe utilization of restored arable land according to claim 1, characterized in that: The micronutrient fertilizers are iron fertilizer and zinc fertilizer, with application rates of 5-10 kg / mu and 3-5 kg / mu, respectively.

5. The method for safe utilization of restored arable land according to claim 1, characterized in that: The gallic acid ester compound is octadecyl gallate, and the alkylamine compound is octadecyl dimethylamine dimethylsilane.

6. The method for safe utilization of restored arable land according to claim 1, characterized in that: The mass ratio of the micronutrient fertilizer to starch, antioxidant, and dispersant is 1:(1-1.4):(0.04-0.08):(0.02-0.05), and the mass ratio of salicylic acid to ethanol in the salicylic acid-ethanol solution is 1:(4-6).

7. The method for safe utilization of restored arable land according to claim 1, characterized in that: The application rate of the foliar inhibitor is 200-300 mL / mu.

8. The method for safe utilization of restored arable land according to claim 1, characterized in that: The carbohydrate compound is trehalose 6,6'-dibenzyl ester, and the amino acid ester is glycine n-octyl ester hydrochloride.

9. The method for safe utilization of restored arable land according to claim 1, characterized in that: The silicon-containing compound is potassium silicate or sodium silicate, the selenium-containing compound is sodium selenate or sodium selenite, the iron-containing compound is ferrous sulfate or ferric sulfate, and the higher fatty alcohol is a C15-C20 fatty alcohol.

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