290results about How to "Reduce cadmium content" patented technology

The present invention relates to a method for controlling heavy metal cadmium content in the rice, belonging to the field of paddy rice planting technology. It is characterized by that in the course of land preparation before rice field seedling transplantation the ferrochelate can be applied into the soil, and said ferrochelate and the soil are uniformly mixed; and in the spike formation stage and filling stage of rice the ferrochelate also can be respectively applied in the rice field. Said method can make cadmium content in the rice be less than 0.2mg / kg.

The invention discloses a method for controlling the accumulation of heavy metal cadmium in rice, and belongs to the technical field of rice planting. The method comprises the following steps of: (1) before the land preparation for seedling transplanting, applying a divalent manganese chelate in soil and uniformly mixing the divalent manganese chelate and the soil; (2) during a period from 15 to 20 days after seedling transplanting to 35 to 45 days after the seedling transplanting, spraying aqueous solution of a divalent manganese fertilizer once every other 7 to 10 days; (3) spreading the divalent manganese chelate in the early booting stage and the grouting stage of the rice respectively; (4) irrigating the paddy land within 3 to 5 days after the soil application of the divalent manganese chelate; (5) from the earing period of the rice to the ripening period of the rice, spraying the aqueous solution of the divalent manganese fertilizer once every other 7 to 10 days; and (6) after the soil application of the divalent manganese chelate, applying the divalent manganese chelate in the same way each year, but with an application rate which is reduced by half or three quarters. The method adopts soil application and leaf surface spraying application of the divalent manganese fertilizer and is more effective. The method is wider in application range, more economic and effective and is capable of improving the mineral nutrient element content of the rice and overcoming the adverse effects of the prior art.

The invention discloses an application of melatonin in reducing cadmium accumulation in plants. The application includes the following steps: (1) mixing melatonin and additives to form aqueous solution; (2) spraying the aqueous solution on plant leaf surfaces under cadmium stress or filling the aqueous solution in nutrient solution or soil where plants grow. The melatonin can quickly and efficiently reduce cadmium content in plant leaves, change distribution of cadmium ions in plant cells, and relieve damage of cadmium to cells; in addition, the melatonin is simple to prepare and convenient to use, does not cause product and environment pollution, does not generate phytotoxicity easily and has a wide application prospect.

The invention discloses a method for reducing the content of cadmium in middle rice. The method includes the following steps that after middle rice of the first year is harvested, middle rice straw is returned to the field directly, and tillage is conducted so that the middle rice straw can be evenly mixed with soil; hyperaccumulation plants are planted in a paddy; after the hyperaccumulation plants are removed from March to May in the second year, soil heavy metal passivator is scattered on the surface of soil of the paddy; tillage is conducted, and base fertilizer is applied 3-5 days later; tillage is conducted, and rice is transplanted; during planting of rice, a foliar resistance control agent is sprayed in the later tillering stage and the booting stage of rice respectively, wherein spraying time interval is 5-10 days; field drying is conducted in the later tillering stage, natural drying is conducted in the maturation stage, and flooding irrigation is conducted in other development stages. According to the method, crop production and straw resource utilization are not affected, the dual targets of reducing the paddy soil cadmium content and reducing the rice cadmium content are achieved under the combined action of plant extraction, soil passivation, foliar resistance control and water management, and effects are more remarkable compared with other combination technologies.

The invention relates to a fertilizer applying method for controlling the heavy metal cadmium accumulation of rice and belongs to the technical field of rice planting. The method comprises the following steps that 1) the land preparation is carried out before the seedling transplanting, and sulfides are applied into soil and are fully and uniformly mixed with the soil; or the land preparation is carried out before at least 15 days of the seedling transplanting, sulfates are applied into the soil and are fully mixed with the soil, and the rice field is kept to be in a waterflooding state; 2) during the first top application in the rice production, the sulfides are scattered and applied, and in addition, the soil is kept to be in the waterflooding state; 3) the sulfides or the sulfates are applied according to steps 1) and 2) during the rice planting in each time in the first year or the second year, the method and the step for applying the sulfides or the sulfates after the second year are the same as those of 1) and 2), but the application quantity is halved or is reduced by 3 / 4, or the sulfides or the sulfates are applied according to the steps 1) and 2) every two years after the second year. The fertilizer applying method has the advantages that sulfur fertilizers with wide resources are used, the consumption is low, the price is low, the use cost is low, and the cadmium content in the rice can be obviously reduced.

The invention relates to a crop rotation matching and fertilizing method capable of controlling accumulation of rice heavy metal cadmium and belongs to the technical field of rice planting. The crop rotation matching and fertilizing method provided by the invention comprises the steps of 1) selecting cruciferae or leguminous crop with high sulphur content as a previous crop; 2) applying sulphur base fertilizer with sulphur ratio of 0.25-5.0kg / 666.7m<2> when the previous crop is planted, or spraying 0.05-1.0% of sulphate for at least 1-3 times in a reproductive stage; 3) taking the previous crop as green manure, smashing or directly turning the previous crop into soil to be mixed with the soil 5-15 days before rice transplantation, and carrying out waterflooding on the transplanted rice seedling; and 4) repeating the steps 1)-3) year over year. The previous crop matching mode adopted in the invention roots in the traditional peasant production mode, sulphur fertilizer is also taken as the traditional farming measure, an operation process is simple, price is low, usage cost is low, the crop rotation matching and fertilizing method provided by the invention is universally applicable to heavily, medially and mildly cadmium-polluted rice field and crop production lands in China, and cadmium content in rice can be obviously reduced.

The invention relates to a granular acidic or acidified soil conditioner and a preparation method thereof. The granular acidic or acidified soil conditioner comprises the following components in parts by weight: 70-90 parts by weight of calcium magnesium phosphate fertilizer, 5-15 parts by weight of humic acid salt and 5-15 parts by weight of filler. The invention further relates to the preparation method of the granular acidic or acidified soil conditioner. The preparation method comprises the steps: preparing the filler, preparing a spray, pelletizing, drying and screening. The granular acidic or acidified soil conditioner is granular, and is convenient to use, and convenient to mechanically apply. The preparation method of the granular acidic or acidified soil conditioner has the advantages of low requirement of production equipment, simple production process, high yield, low cost and environmental friendliness; conventional equipment is adopted without adding special equipment.

The invention relates to a mushroom cultivation substrate, which consists of solid materials and water. The mushroom cultivation substrate is characterized in that the solid materials comprise by weight 78-82% of broad-leaf tree sawdust, 14-20% of wheat bran, 0.8-1.2% of sucrose, 0.7-1.2% of gypsum powder, 0.8-1.5% of fused calcium-magnesium phosphate fertilizer, and 0.8-1.5% of a compound fertilizer, and that water in the mushroom cultivation substrate accounts for 58-62% of the total weight of the solid materials. According to the mushroom cultivation substrate, fused calcium-magnesium phosphate fertilizer and the compound fertilizer serving as mushroom heavy metal modifying agents are added in the conventional cultivation substrate of the mushroom, the addition amount of fused calcium-magnesium phosphate fertilizer and the compound fertilizer is within the range of 0.8-1.5%, so that the cadmium content in the mushroom is reduced by 18-39.6%, and the mercury content is reduced by 19.9-29%; moreover, the accumulation function of the heavy metals can be reduced to the largest degree, and the adverse effects on important agronomic characteristics such as mycelium spreading speed, yields and the like are avoided.

The invention discloses an immobilized Bacillus having phosphate dissolving and heavy metal passivation functions and a preparation method and an application thereof, which belong to the technical field of cadmium pollution soil biological restoration. The immobilized Bacillus comprises biological carbon and Bacillus cereus B19, can be used for restoring the soil with severe cadmium pollution, and has better restoration effect. The composite microbe fertilizer contains the immobilized Bacillus, an organic fertilizer and an inorganic nutrient having the phosphate dissolving and heavy metal passivation functions. The composite microbe fertilizer has the advantages that cost is low, soil available nutrient content is increased, yield increase is achieved, the soil with cadmium pollution is effectively repaired, introduction of heavy metal cadmium in human body with crops can be effectively controlled, agricultural product safety is guaranteed; in addition, the composite microbe fertilizer cannot change a farmland utilization mode without secondary pollution, is conveniently used, and is economic and feasible.

The invention discloses a fertilizer capable of controlling rice cadmium accumulation and a preparation method of the fertilizer, and belongs to the technical field of fertilizers. The fertilizer is prepared by the following raw materials based in part by weight: 100 parts of organic matter based on 10% of moisture content, 1-50 parts of sulfur source based on sulfur, 0.1-20 parts of strong base, and water which is 20-100% of the total weight of the organic matter, the sulfur source and the strong base. Compared with the prior art, the fertilizer is economic and effective. The fertilizer can be combined with the traditional sulfur fertilizer application technology, so that peasants can accept the fertilizer, and the operation procedures are easier.

The invention discloses a contaminated soil repair method and a repair device. The repair method comprises the steps of (S1) vacuum thermal separation: performing thermal separation on soil in a vacuum environment so as to separate hazardous substances, and purifying the hazardous substances; (S2) chemical washing: chemically washing the soil on which the vacuum thermal separation is performed; (S3) reduction treatment: adding a reducing agent to the soil on which the chemical washing is performed; (S4) repair: applying a soil repair agent to the soil on which the reduction treatment is performed; (S5) stabilizing treatment: applying a heavy metal cadmium stabilizer and a microbial agent to the repaired soil; and (S6) improvement and maintenance: improving and maintaining the stabilized soil. According to the contaminated soil repair method, the contaminated soil can be thoroughly repaired once with low cost and high efficiency.

The present invention discloses a repairing chemical agent for reducing cadmium contamination of crops and a using method. The repairing chemical agent comprises the following raw materials: 5-45 parts by weight of a natural surfactant, 4-15 parts by weight of an oxidant and 10-60 parts by weight of a silicate mineral material. On one hand, the repairing chemical agent disclosed by the present invention, through irrigation and other farming activities, can be adsorbed on the surfaces of soil particles, so that a property of a solid-liquid interface is changed, the adhesion between cadmium ions in soil and the soil is weakened, the separation of heavy metal ions from the soil is promoted, the heavy metal ions generate a complex with active materials, and thus, the absorption of heavy metals by the crops is reduced. On the other hand, the repairing chemical agent reacts with unstable cadmium in the heavy metal contaminated soil, and stable insoluble cadmium salt precipitation is generated, so that the cadmium content in the planted crops is significantly reduced, and the requirements on the quality of safe agricultural products are met.

The invention discloses a paddy rice dedicated cadmium-reducing biological organic fertilizer and a preparation method thereof, and relates to the technical field of agricultural fertilizer; the paddy rice dedicated cadmium-reducing biological organic fertilizer is prepared by mixing granulation of 1-3 parts by weight of urea, 2-6 parts by weight of diammonium phosphate, 1-3 parts by weight of potassium sulfate, 0.5-1.5 parts by weight of a trace element, 30-50 parts by weight of livestock and poultry manure, 20-40 parts by weight of agricultural crop straw, 10-30 parts by weight of humic acid, and 0.5-1.5 parts by weight of biological bacteria. The paddy rice dedicated cadmium-reducing biological organic fertilizer is applied, aims at paddy rice fertilizer-requiring characteristics, has strong specificity and high fertilizer efficiency, and can effectively reduce the cadmium absorption of paddy rice; the paddy rice yield can be increased by 5-10%, and the quality of produced rice can meet requirements of green food. The paddy rice dedicated cadmium-reducing biological organic fertilizer is mainly used for paddy rice, and also can be used for soybean, corn, fruit trees, vegetables and other crops. When application, the paddy rice dedicated cadmium-reducing biological organic fertilizer is mainly used as a base fertilizer for furrow application, and also can be used as a topdressing fertilizer for broadcasting application.

The invention discloses application of monopotassium phosphate to reduce rice cadmium accumulation. The application disclosed by the invention is as follows: monopotassium phosphate is applied to soil in the event of preparing a land before transplanting rice; or / and monopotassium phosphate is sprayed to the upper parts of rice after transplanting rice till maturing. According to the invention, novel application of monopotassium phosphate is provided; monopotassium phosphate is capable of effectively controlling cadmium accumulation in rice; monopotassium phosphate is capable of respectively reducing cadmium contents in rice cadmium high-accumulation rice Yongyou 9 and rice cadmium high-accumulation rice Xiushui 09 brown rice to be above 80% and 85% maximally; the cadmium contents in brown rice are only 0.04 mg / kg and 0.02 mg / kg and are far below nationally regulated 0.2 mg / kg; a good solving way is provided for rice heavy metal pollution; furthermore, both the application number and the application amount of monopotassium phosphate are very low; the application disclosed by the invention is low in cost and convenient for operation.

The invention relates to a method for repairing cadmium contaminated soil and provides a method for repairing soil cadmium contamination through titanium gypsum. The method is short in repairing period, low in cost and free of secondary pollution to the soil, and improves the use value of waste solid titanium gypsum. After the cadmium contaminated soil steeps in the field, the titanium gypsum is evenly added into the soil, and the water content of the soil keeps 30-40% of the field capacity; the raw titanium gypsum comprises CaSO4, Fe2O3, MgO, Al2O3, SiO2, P2O5 and TiO2; the Fe2O3 exists in a ferric hydroxide colloid form. The method has the beneficial effects that the titanium gypsum is added into the soil, so that the pH, CEC and Eh of the soil are effectively improved, the content of cadmium easily absorbed by plants is reduced, the bio-availability of the cadmium is decreased, and the repairing period is short; the titanium gypsum contains a large number of microelements needed by growth of plants, such as Fe, Mg, Ca and S, so that the yield of crops is improved, and no pollution is generated to the soil; efficient utilization of the titanium gypsum soil is achieved, the cost is low, and popularization is easy.

The invention discloses a production method for cadmium-polluted rice land governing and rice cadmium reduction. The production method comprises the following steps: a, preparing biomass charcoal by late rice straw to return to field and prepare milk vetch green manure in winter; b, overturning and pressing milk vetch green manure along with spraying lime; c, regulating and controlling water fertilizer of early season rice; d, preparing biomass charcoal by straw in early season to return to field; e, regulating and controlling water fertilizer of late rice. The production method improves soil fertility, reduces the effectiveness of cadmium polluted soil, combines the water fertilizer regulation and management, and effectively stops and controls the cadmium transfer towards the rice planting body, in particular to rice; the production method provides a low-price and practicable environmental protection regulating technology for the green repair of soil heavy metal cadmium pollution and rice cadmium reduction on the polluted rice land, and provides technical support to the polluted rice field governing and rice cadmium reduction in the southern China.

The invention discloses a method for producing rape-middle rice in a crop rotation way in cadmium-moderately-contaminated soil while repairing, and belongs to the technical field of environmental governance of the contaminated soil. The method comprises the following steps: (1) planting rape Zheyou 50 in the cadmium-contaminated soil, spraying a cadmium activator on rape leaf surfaces respectivelyin a bolting period and a flowering period, cultivating until harvest, and removing all; (2) leveling the soil, applying a cadmium passivation conditioner and evenly mixing with surface soil; and (3)after 6-8 days, transplanting middle rice Yongyou 15, performing submergence treatment during a whole growth period, spraying a zinc-enhanced cadmium resistance control agent on leaf surfaces respectively at a tillering stage, a booting stage and a grain-filling stage, draining water in the fields one week before the harvest of the middle rice, and removing all straw after the harvest of the middle rice. The method disclosed by the invention utilizes crop rotation of the cadmium-enriched rape and the cadmium low-accumulation high-quality middle rice to cooperate with reasonable water management, and can be used for repairing the soil while guaranteeing the safe and high-quality production of crops.

The invention discloses an acidic soil conditioner and an application thereof. The acidic soil conditioner comprises, by mass, 33-36% of rice husk ash, 14-16% of quicklime, 24-26% of calcium magnesiumphosphate, 22-24% of sepiolite and 1.5-2% of dicyandiamide. The conditioner includes the rice husk ash, quicklime, calcium magnesium phosphate, sepiolite and dicyandiamide, and the rice husk ash, quicklime and calcium magnesium phosphate fertilizer are alkaline substances and can increase the pH value of the soil. The rice husk ash and calcium magnesium phosphate commonly act to supplement nutrients lost due to soil acidification. The sepiolite and dicyandiamide commonly act to improve the nitrogen fertilizer utilization rate. The rice husk ash and sepiolite commonly act to improve and repairacidic heavy metal contaminated soil. The rice husk ash, calcium magnesium phosphate and sepiolite commonly act to inhibit the enrichment of cadmium and other heavy metals in crops. The acidic soil conditioner can comprehensively improve the properties of the soil, improve the fertility level of the soil, reduce the cadmium contamination risk of the crops and increase the yield of the crops.

The invention belongs to the technical field of agriculture, in particular to a cultivation method for reducing cadmium content in peanut seed kernels. By applying fertilizer mu by mu and dressing seeds with rare earth, the cultivation method reduces the cadmium content in the peanut seed kernels and guarantees peanut quality as well as the health of eaters.

The invention discloses a method for reducing effective cadmium content of soil. The method provided by the invention is characterized in that a passivator of meerschaum powder of 60 meshes is applied to farmland polluted by cadmium; a utilization amount equation of the passivator of the meerschaum powder of 60 meshes is determined according to effective cadmium content of soil; and a utilizationmethod of the passivator of the meerschaum powder comprises 1, removing crop straws of the farmland or crushing the crop straws, 2, uniformly scattering the passivator of the meerschaum powder of 60 meshes on the surface of soil of the farmland by an artificial method or a mechanical method, 3, mechanically turning the soil at least twice for uniform mixing, wherein a soil turning depth is in a range of 15 to 20 centimeters, and in application, it is guaranteed that wind power is below a level of 2 to 3 or the meerschaum powder do not be blown away, and 4, sowing crops and then carrying out irrigation 2 to 3 times under the condition that a normal demand amount of agricultural production water is satisfied, wherein quality of the agricultural production water for the irrigation satisfies a farmland irrigation water quality standard and an irrigation method is aopted. The method for reducing effective cadmium content of soil has the advantages of wide application scope, low cost, simple operation, no influence on agricultural production and environmental benefits, can be utilized for effective treatment on farmland which has a large area of a cadmium-polluted part, can reduce the content of cadmium which can be absorbed by crops, and can prevent penetration of effective cadmium of the soil into agricultural products.

The invention discloses a method for mid-season rice-wheat rotation in cadmium mild contamination soil and belongs to the technical field of contamination soil environment management. The method includes: (1), in 5-8d before crop transplanting, applying a soil cadmium passivation conditioner on the cadmium mild contamination soil, and well mixing with plough layer soil; (2), transplanting mid-season rice Yongyou 7850, waterflooding in the whole growth period, spraying a zinc reinforced cadmium blocking and controlling agent to leaves in the tillering period, the booting period and the groutingand fruiting period respectively, and draining field water in one week before harvesting mid-season rice; (3), fully moving out straw after the mid-season rice is harvested, directly sowing wheat Ningmai 13, cultivating to harvesting, and removing wheat straw completely. According to the mid-season rice-wheat rotation mode in the method, repair of the cadmium mild contamination soil is completedwhen agricultural production is completely normal, and the method is free of economic benefit loss and easy for farmers to accept; harvested straw is moved out of farmland, so that no secondary pollution is caused.

The invention relates to a fertilizer for reducing cadmium content of peanut and application thereof. The fertilizer for reducing the cadmium content of the peanut is prepared according to alkalinity or acidity of soil; 30-40kg gypsum, 0.6-0.8kg of copper sulfate, 0.8-1kg of zinc sulfate, 0.5-0.8kg of ferrous sulfate, and 1-1.5kg of manganese sulfate are compounded, mixed uniformly and applied per hectare of alkaline or neutral soil; and 40-50kg of lime, 0.6-0.8kg of copper sulfate, 0.8-1kg of zinc sulfate, 0.5-0.8kg of ferrous sulfate, and 1-1.5kg of manganese sulfate are compounded, mixed uniformly and applied per hectare of acid soil. According to the fertilizer, adsorption and antagonistic action between elements is utilized, and elements with the same valence as cadmium are applied in a balanceable mode, so that the adsorption of the peanut on the cadmium can be inhibited, the content of the cadmium in peanut seeds is reduced, the requirement of the peanut on various nutrient elements can be met, decayed fruits caused by interaction of potassium and calcium due to high-quantity application of calcium are avoided, the yield of the peanut is improved, and high yield and food safety are synchronized. Experiments show that according to the fertilizer, the fruit number per plant is increased to be 0.9-1.5 / plant, the milled rice rate is improved by 5.6 percent-12.1 percent, the yield of legume is increased by 9.8 percent-16.2 percent, and the content of the cadmium in the peanut seeds is reduced by 22.1 percnet-39.0 percent.

The invention provides a remediation method for heavy metal cadmium-contaminated farmland. The method comprises the steps as follows: water is added to the farmland, so that the farmland is soaked inthe water; a ferric salt solution is added to the treated heavy metal-contaminated farmland, and the farmland is ploughed, broken and then flattened; the surface of soil is covered with a fiber film;and the steps are repeated as a cycle. The distance between the soaking water surface and the surface of the farmland during still standing ranges from 0.5 cm to 1.5 cm, the farmland is ploughed and broken for 1-3 times, the concentration of the ferric salt solution is 0.5-1.5 mg / L, ferric salt is ferric chloride or ferric sulfate, the fiber film is a polypropylene fiber film containing activatedcarbon, modified diatomite and modified kaolin, the fiber film covering time ranges from 3 days to 5 days, and the circulating times ranges from 3 times to 5 times. The remediation method has the obvious treatment effect, the content of cadmium in the heavy metal-contaminated farmland can be effectively reduced, used reagents and materials such as the ferric chloride, the polypropylene fiber filmand the like are low in price and easy to obtain, the treatment cost is reduced, the treatment efficiency is high, and the farmland remediation speed is high.

The invention provides a quantum dot diaphragm and a backlight module. The quantum dot quantum comprises a first barrier film layer, a second barrier film layer, wherein the second barrier film layeris disposed opposite to the first barrier film layer, a light emitting layer, wherein the light emitting layer is disposed between the second barrier film layer and the first barrier film layer. The material of the light emitting layer comprises green fluorescent powder, red quantum dots and dispersion medium, wherein the green fluorescent powder comprises gamma-AlON: Mn2+, Mg2+green fluorescent powder. The backlight module comprises the quantum dot diaphragm, a light transmission plate, wherein the light transmission plate comprises a light incident surface and a light emitting surface, at least one light source, wherein the light source is arranged opposite to the light incident surface of the transmission plate. The quantum dot diaphragm is attached to the light emitting surface of thelight transmission plate. The quantum dot diaphragm and the backlight module has the technical effects that the novel quantum dot diaphragm is formed by utilizing the special structure of the quantumdot diaphragm and the material of the light emitting layer, so that the use of the green quantum dot material is reduced, the high color gamut is realized, the water and oxygen are highly blocked, theproduction cost is reduced, and the green and environmental protection is realized.

The invention provides a compound mixed biological bacterial fertilizer for restoring cadmium contaminated soil; the compound mixed biological bacterial fertilizer includes NPK nutritious components and agricultural rare earth nitrate, a catalyst waste agent, a microbial agent, a humic acid mineral powder, sepiolite, plant ash, kaolin and zeolite with proper proportion; after the compound mixed biological bacterial fertilizer is applied to the cadmium contaminated soil, under the synergy of all the components, the contaminated soil is effectively restored while cadmium in the soil is effectively passivated and immobilized, the cadmium activity in the soil is decreased significantly, and the absorption of crops on cadmium is facilitated to be reduced, so as to make the cadmium content in the crops decreased significantly; the compound improver has relatively good stability and environmental friendly characteristic, does not produce secondary pollution, and is low in cost and prone to large-area promotion; when the compound mixed biological bacterial fertilizer is applied to the cadmium contaminated soil, the application amount is only 10-200 kg / hm<2>, the cadmium content in the crops can be significantly reduced, and the crops are allowed to meet national edible safety standards.

The invention belongs to the technical field of agricultural fertilizer application, and discloses a leaf surface fertilizer for reducing the cadmium content in rice and a preparing method of the leafsurface fertilizer. The leaf surface fertilizer for reducing the cadmium content in rice is composed of KH2PO4 with the concentration of 0.02-0.04 mol / L, zinc chloride with the concentration of 0.02-0.03 mol / L, manganese sulfate with the concentration of 0.1-0.2 mol / L and malic acid with the concentration of 0.2-0.3 mol / L. The preparing method includes the steps of weighing 0.0323 mol of KH2PO4,0.0266 mol of zinc chloride, 0.175 mol of manganese sulfate and 0.2669 mol of malic acid, adding 1 L of distilled water, and conducting vibrating and dissolving. According to the leaf surface fertilizer, by spraying a small-molecular acid type component (malic acid) on rice leaves, the endocrine metabolism adjusting and control approach of rice plants is adjusted and controlled, the plants are induced to secrete plant chelating elements capable of preventing heavy metal cadmium ion from being conveyed to grain, and the effect of the cadmium content in rice is reduced.

The invention discloses a method for improving copper slag level in zinc hydrometallurgy process. The method is characterized in that a process of washing copper slag with water in a traditional technology is removed and replaced by the process of pickling the copper slag twice, wherein the process of pickling the copper slag twice comprises the steps of leaching copper-cadmium slag through strong acid at high temperature, slurrying the copper slag for the first time, pickling the copper slag for the first time, slurrying the copper slag for the second time, and pickling the copper slag for the second time. The method is simple and clear in process; when in the actual production, the technological conditions, such as adding sulfuric acid and water, and controlling the temperature, the acidity and the solid-to-liquid ratio, are required; the operation is simple, and the production cost is low. With the adoption of the method, water-soluble zinc and water-soluble cadmium in the copper slag can be recovered, and meanwhile, the purpose of recovering insoluble zinc and insoluble cadmium in the copper slag can be achieved, so that the copper in the copper slag can be further enriched, and as a result, the obtained copper slag is high in level; the copper content in the copper slag can be increased from 45% to be more than 65%, the zinc content in the copper slag can be decreased from 12% to be less than 7%, and the cadmium content in the copper slag can be decreased from 8% to be less than 3.5%; the whole process basically realizes a real sense of clean production; the method is environmentally friendly, and high in economic benefit.

The invention provides a method for evidently lowering the cadmium accumulation of Raphanus sativus and promoting the growth of the Raphanus sativus. The method includes: when Raphanus sativus seedlings grow two true leaves, using melatonin with the concentration being 50-200 micromol*L<-1> to perform leaf surface spraying until leaf surfaces can drip water. The method has the advantages that cadmium content in the Raphanus sativus can be lowered evidently, the photosynthetic pigment content, antioxidant enzyme activity and biomass of the Raphanus sativus can be increased evidently, and the inhibition effect of cadmium on the growth of the Raphanus sativus can be relieved effectively.

The invention relates to a phosphate for lowering the content of cadmium in plants planted in acidic cadmium-containing soil and / or improving the yield of the plants planted in the acidic cadmium-containing soil, and mainly provides an application method and the like of the phosphate for lowering the content of cadmium in the plants planted in the acidic cadmium-containing soil and / or improving the yield of the plants planted in the acidic cadmium-containing soil.

The invention belongs to the technical field of soil remediation, and provides a method for remediating cadmium-contaminated soil by utilizing solanum nigrum and corn intercropping plants, which comprises the following steps: A, soaking solanum nigrum seeds with a seed soaking solution; B, sowing corn seeds and nightshade seeds in an intercropping mode, and after nightshade blooms, applying a strong chemical fertilizer to corn and nightshade; and C, after corn seeds are mature, harvesting corn and nightshade at the same time, wherein the seed soaking solution comprises pullulan, phytase, gibberellin, sodium carbonate, calcium nitrate and sterile water in a mass ratio of 3:(0.5-1):(1.5-2.8):2:10:(45-70). The method solves the problems that the biomass of solanum nigrum is not large, the absorption efficiency of the solanum nigrum to heavy metal pollutants in soil is not high enough, and the quality and economic benefits of corn cannot be guaranteed during corn intercropping.