CN114041392A

CN114041392A - Planting technology for reducing chromium and arsenic content in rice

Info

Publication number: CN114041392A
Application number: CN202111231371.7A
Authority: CN
Inventors: 马烁; 王文燕; 景琪; 徐诗琦; 闫梦洋; 赵颖
Original assignee: China City Environment Protection Engineering Ltd
Current assignee: China City Environment Protection Engineering Ltd
Priority date: 2021-10-22
Filing date: 2021-10-22
Publication date: 2022-02-15

Abstract

The invention relates to the technical field of farmland restoration, in particular to a planting technology for reducing the contents of chromium and arsenic in rice; the planting technology comprises the following steps: seedling raising and transplanting to a rice planting area, applying an organic fertilizer before transplanting, managing water in the rice growth process, spraying a foliar retarding and controlling agent once respectively in a heading stage and a grain filling stage, wherein the foliar retarding and controlling agent comprises urea, monopotassium phosphate, trace elements and silicon powder, and detecting the rice after the rice is mature, particularly detecting the contents of chromium and arsenic in the rice. According to the planting technology provided by the invention, the contents of chromium and arsenic in rice can be effectively reduced through strict water management, application of organic fertilizer containing montmorillonite and multiple spraying of the foliage resistance and control agent, the problem of planting polluted farmlands is solved, and the problem that edible crops cannot be planted in the polluted farmlands is solved.

Description

Planting technology for reducing chromium and arsenic content in rice

Technical Field

The invention relates to the technical field of farmland restoration, in particular to a planting technology for reducing the contents of chromium and arsenic in rice.

Background

With the rapid development of industries such as electroplating and petrochemical equipment production, due to the fact that the early-stage production management consciousness is laggard, the production sewage is discharged out of the standard, pollutants enter irrigation channels and rivers, and the condition of heavy metal pollution (chromium, cadmium, arsenic, mercury, lead and the like) of farmlands is emphasized, so that the necessity and the urgency for developing soil remediation and treatment and risk control of the farmlands in the region are realized. According to the research surface, the average value of the chromium (Cr) content in Chinese soil reaches 78.94mg/kg, which is obviously higher than the background value of 57.30mg/kg, and the chromium-polluted soil not only reduces the production capacity of farmland soil, but also causes the chromium content of edible parts to exceed the food safety edible standard due to the accumulation of chromium in crops planted in the farmland soil. Common remediation techniques for chromium-contaminated farmlands include low-accumulation crop planting and agronomic regulation; the low-accumulation crops refer to crop varieties which can normally grow on the polluted soil, but the heavy metal content of edible parts of the crops is low or not over standard; the agricultural technology mainly adopts measures of increasing organic fertilizer, planting green manure, spraying leaf surface, managing moisture and the like for regulation and control.

Chinese patent document CN 105750323 a discloses a method for remediating chromium pollution in farmland under the condition of plant production, which is mainly applied in the field in the form of passivating agent to passivate the Cr element with biological effectiveness, but only transforms the form of Cr, and if environmental changes later, the biological effectiveness of Cr may be enhanced.

In view of various defects and limitations of the passivation technology in the current polluted farmland restoration process, an economic and effective planting mode is researched, and the method has important social significance and environmental significance

Disclosure of Invention

In order to solve the problems, the invention provides a planting technology for reducing the content of chromium and arsenic in rice, which comprises the following steps:

step S1: seedling is carried out in a seedling raising field, and rice seedlings grow to 25-35 cm and are transplanted;

step S2: applying 400-500 kg/mu of organic fertilizer to a rice planting area 10-15 days before transplanting rice;

step S3: transplanting the rice seedlings in the step S1 into a rice planting area to which organic fertilizer is applied;

step S4: flooding the rice planting area before the rice grows fully;

step S5: spraying a leaf surface control agent to the rice once in the heading stage of the rice;

step S6: spraying a leaf surface control agent to the rice once in the rice filling period;

step S7: draining and drying the paddy fields in the sun 7-10 days before harvesting the paddy rice;

step S8: after the rice is mature, the contents of chromium and arsenic in the rice are respectively detected.

Further, the organic fertilizer in step S2 is prepared by fermenting the following raw materials: 100 parts of organic bottom material, 0.1-0.2 part of leavening agent and 0.4-0.6 part of rice bran, wherein the organic bottom material comprises the following components in parts by mass: 2-4: 2-4: 1-5: 0.2-0.5 of vinasse, straws, chaffs, mushroom dregs and montmorillonite.

Further, the fermentation temperature of the organic fertilizer in the step S2 is not higher than 65 ℃.

Further, the row spacing for transplanting the rice in the step S3 is 25-35 cm, and the planting spacing is 11-11.7 cm.

Further, the foliage resistance and control agent in the step S5 and the step S6 is prepared from the following raw materials in parts by weight: 10-15 parts of urea, 10-20 parts of monopotassium phosphate, 0.5-3 parts of trace elements, 15-25 parts of silicon powder and a plurality of water.

Further, the trace elements comprise at least one of calcium, zinc, magnesium, iron and selenium.

Further, the particle size of the silicon powder is 10-20 nm.

Further, the spraying amount of the foliar retarding and controlling agent in the step S5 and the step S6 is 160-240 ml/mu, and the foliar retarding and controlling agent is applied to the leaf surfaces of the rice.

Further, when the flooding treatment is performed in the step S4, the water layer on the soil surface is not lower than 3 cm.

The organic matter is one of important components in soil, the main component of the organic matter in the soil is humic matter, the main active part of the humic matter is humic acid, the humic acid in the soil is easy to form a soluble compound with iron ions so as to block the adsorption of heavy metals, and the humic acid can be matched with the heavy metals so as to influence the activity of the heavy metals in the soil, so that the organic matter is an important factor influencing the biological effectiveness and the mobility of the heavy metals in the soil. Heavy metal ions entering the soil from the environment can be fixed in the soil through a series of physical or chemical reactions with organic matters in the soil, so that the biological effectiveness of the heavy metal ions is influenced. Farm fertilizers, composts, biosolids and biosolid composts can effectively reduce the utilization rate of heavy metal ions in soil.

Montmorillonite in the organic fertilizer is a clay mineral, has a high specific surface area, and has high adsorption capacity and surface complexing capacity for heavy metals such as chromium and arsenic. The organic fertilizer is mainly applied in the form of a base fertilizer, rotary tillage is performed by matching with a rotary cultivator, so that the organic fertilizer is fully dispersed in soil, humic acid in the soil can easily form a soluble compound with iron ions after the organic fertilizer with higher decomposition degree is applied, meanwhile, hexavalent chromium in the soil can be reduced into trivalent chromium in the decomposition process, the trivalent chromium is fixed in the soil after being combined with the soluble compound, and the biological effectiveness and the mobility of the chromium in the soil are reduced.

According to the method, a flooding measure is adopted before the rice grows fully, a water layer with the thickness not less than 3cm is required on the soil surface, the flooding depth of the rice in different periods can be properly adjusted, and the dry-wet alternation from the tillering period to the grouting period of the rice is strictly prevented. The soil is flooded to form a reduction condition, hexavalent chromium forms trivalent chromium under the reduction condition, the biological effectiveness of the trivalent chromium is low, the trivalent chromium is not easy to be absorbed by rice, and meanwhile, the effectiveness of arsenic is opposite to that of other heavy metals, so that the effectiveness of arsenic is increased under the flooding condition, the water is strictly flooded before the grouting period of the rice, the field is properly sunned after the booting period, the water is drained and the field is sunned within 7-10 days before harvesting after the rice grows to the wintering period, and the contents of chromium and arsenic in the rice can be effectively reduced.

The foliage resistance control technology is characterized in that the physiological active substances are used for preventing heavy metals from moving to edible parts, so that the content and accumulation of the heavy metals are reduced, the aim of safe production of agricultural products is fulfilled, the foliage resistance control principle is different in component, and the main components of the foliage resistance control agent comprise beneficial elements such as silicon, selenium, zinc, manganese, iron and the like and the physiological active substances such as phytohormones and the like. The application of the foliage resistance control agent can improve the stress resistance of crops, reduce the heavy metal content of edible parts and improve the quality and the yield of agricultural products. The foliar control agent is sprayed in the heading stage and the filling stage of the rice, so that the content of chromium in the rice can be effectively reduced.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects:

1) according to the planting technology for reducing the contents of chromium and arsenic in rice, the contents of chromium and arsenic in rice can be effectively reduced through strict water management and the application of the organic fertilizer containing montmorillonite, so that the problem of planting polluted farmlands is solved, and the problem that edible crops cannot be planted in the polluted farmlands is solved;

2) according to the planting technology for reducing the chromium and arsenic content in the rice, provided by the invention, the foliage resistance and control agent is sprayed in the heading stage and the grouting stage of the rice, so that the heavy metal can be effectively prevented from running to an edible part, and the heavy metal content and accumulation are reduced, so that the chromium content in the rice can be reduced, and the quality and yield of agricultural products are improved;

3) according to the planting technology for reducing the chromium and arsenic content in the rice, the chromium and arsenic content of the rice is detected after the rice is mature, so that rice varieties suitable for local planting can be screened out, and the problem of local grain safety is solved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by those skilled in the art without any creative work based on the embodiments of the present invention belong to the protection scope of the present invention.

In the embodiment of the application, in order to improve the survival rate of the rice and increase the growth and development of the rice, the seedlings are firstly grown in a seedling bed, and then the seedlings are transplanted to a rice planting area. The specific method comprises the steps of sowing in a seedling raising field after rice sprouts, transplanting after rice seedlings grow to be about 30cm high, and timely supplementing the seedlings according to the green turning condition after transplanting.

In some embodiments, the seedling age of the rice seedling is controlled, the hybrid rice can be transplanted after the seedling age reaches 30-40 days, the seedling age of the conventional rice is 40-50 days and cannot exceed 60 days, and the seedling age of the transplanted rice is determined according to the actual rice variety. Generally, the seedling age of the rice selected for transplanting is about 30 days, the leaf age is about 5.0, the seedling height is 15-20 cm, the stem base width of a single plant is 0.3-0.4 cm, and the rice has erect leaves, green color, no yellow leaves and no spots. The seedling number, the seedling height and the thickness between seedling trays and holes are uniform.

In some embodiments, the density row spacing is about 30cm, the plant spacing is about 11cm, 27-30 ten thousand holes per hectare, 3-4 seedlings per hole and about 100-120 ten thousand basic seedlings are transplanted, and timely seedling supplement is performed according to the survival condition of rice seedlings.

In the embodiment of the application, before transplanting rice, organic fertilizer is applied to a rice planting area, specifically, organic fertilizer with high humus content is used as a suitable material, vinasse, straw, chaff, mushroom dregs and montmorillonite are mixed according to the mass ratio of 3:2:3:2.5:0.4, the mixture is turned and stirred uniformly, 1 kg of leavening agent and 5 kg of rice bran are added into 1 ton of organic bottom materials for dilution, and then the mixture is turned and stirred uniformly and fermented again. The fermentation process is that the mixed organic fertilizer is spread, the spreading area is not less than 2 meters high, 3 meters wide and 3 meters long, the fermentation temperature in the organic fertilizer fermentation process is not higher than 65 ℃, the fermentation temperature can be controlled at 65 ℃, the nutrition can be influenced by the overhigh fermentation temperature, the whole fermentation process is not less than 10 days, the finished organic fertilizer is fluffy and dark brown, has slight bouquet or clay taste, is rich in nutrition, and the fermented organic fertilizer can be applied according to the requirement.

In some embodiments, the organic fertilizer is applied in the form of a base fertilizer at an application rate of 500 kg/acre in the rice planting area.

In some embodiments, the lees, the straws, the chaffs, the mushroom dregs and the montmorillonite in the organic fertilizer can be configured according to other proportions, the configuration proportion can be determined according to the specific situation of a rice planting area, and the configuration proportion is not limited in the embodiments of the application.

In the growth process of the rice, strict water management is carried out, a flooding measure is adopted before the rice grows fully, a water layer with the thickness not less than 3cm is required on the soil surface, and the contents of chromium and arsenic in the rice can be effectively reduced through the water management.

In the embodiment of the application, the foliar retarding and controlling agent is sprayed on the rice leaves in the heading period and the filling period, the spraying amount is 200 ml/mu each time, and the foliar retarding and controlling agent comprises 10-15 parts of urea, 10-20 parts of monopotassium phosphate, 0.5-3 parts of trace elements, 15-25 parts of silicon powder and a plurality of water.

In some embodiments, the foliage resistance control agent is prepared by dissolving 12 parts of urea, 16 parts of monopotassium phosphate and 2 parts of trace elements in water, standing for 30min, adding 20 parts of high-purity silicon powder, fully mixing, reacting for 15 hours, standing, filtering, and barreling, wherein the spraying is carried out as required when in use.

Further, in order to ensure that the leaf surface resistance control agent can be well absorbed by rice, the particle size of the silicon powder is 10-20nm, and the silicon powder can be ground and sieved before use to ensure that the particle size meets the requirement and is convenient to be absorbed by the rice. The foliage inhibitor can block chromium from running to the edible part of rice, so that the chromium content in the rice is reduced.

Draining water and drying in the sun within 7-10 days before harvesting after the rice grows to be in a waxy yellow stage, collecting mature rice and detecting, particularly detecting the content of chromium and arsenic in the rice.

The farmland of the embodiment is positioned on Jianghhan plain, the average concentration of chromium in the farmland soil is 73mg/kg, the arsenic content is 28mg/kg, the chromium content in rice in the previous year is 1.88mg/kg, and the arsenic content is 0.2mg/kg, which exceeds the agricultural product limit requirement in the national standard food for food safety (GB 2762-2017).

In the embodiment, the 'Zhongzao 35', 'Ezao 18', 'Ling Eryou 32', 'Zhongjiazao 17', 'Jianghao 39' and 'Eryou 6' are planned to be planted in the farmland region, and the contents of chromium and arsenic in the mature rice are detected under the use of the same organic fertilizer and the leaf surface resistance and control agent.

Example 1

Adding the organic fertilizer into the polluted soil at 500 kg/mu, then ploughing the farmland, ensuring the uniform spreading of the organic fertilizer in the organic fertilizer spreading operation process, carrying out rotary tillage on the farmland after the spreading is finished, and adding water for field soaking. Then transplanting 35% of the seeds in the morning, paying attention to the growth vigor of the rice, preventing and controlling the diseases and the pests of the rice at different periods, and spraying the silicon-rich leaf surface resistance and control agent at the heading period and the filling period, wherein 200 ml/mu is sprayed each time. Before the rice grows completely, a flooding measure is adopted, a water layer with the soil surface not less than 3cm is required, and chromium and arsenic in the rice are respectively detected after the rice is mature.

Example 2

Adding the organic fertilizer into the polluted soil at 500 kg/mu, then ploughing the farmland, ensuring the uniform spreading of the organic fertilizer in the organic fertilizer spreading operation process, carrying out rotary tillage on the farmland after the spreading is finished, and adding water for field soaking. Then carrying out early-Hubei 18 transplanting, paying attention to the growth vigor of the rice, carrying out pest control on the rice at different periods, and spraying a silicon-rich foliage resistance and control agent at the heading period and the filling period, wherein 200 ml/mu is sprayed each time. Before the rice grows completely, a flooding measure is adopted, a water layer with the soil surface not less than 3cm is required, and chromium and arsenic in the rice are respectively detected after the rice is mature.

Example 3

Adding the organic fertilizer into the polluted soil at 500 kg/mu, then ploughing the farmland, ensuring the uniform spreading of the organic fertilizer in the organic fertilizer spreading operation process, carrying out rotary tillage on the farmland after the spreading is finished, and adding water for field soaking. Then transplanting 'Lingshangyou 32', paying attention to the growth vigor of rice, performing rice pest control at different periods, and spraying a silicon-rich leaf surface resistance control agent at the heading period and the filling period, wherein 200 ml/mu is sprayed each time. Before the rice grows completely, a flooding measure is adopted, a water layer with the soil surface not less than 3cm is required, and chromium and arsenic in the rice are respectively detected after the rice is mature.

Example 4

Adding the organic fertilizer into the polluted soil at 500 kg/mu, then ploughing the farmland, ensuring the uniform spreading of the organic fertilizer in the organic fertilizer spreading operation process, carrying out rotary tillage on the farmland after the spreading is finished, and adding water for field soaking. Then transplanting 'Zhongjiazao 17', paying attention to the growth vigor of the rice, preventing and controlling the diseases and pests of the rice at different periods, and spraying a silicon-rich leaf surface resistance and control agent at the heading period and the filling period, wherein 200 ml/mu is sprayed each time. Before the rice grows completely, a flooding measure is adopted, a water layer with the soil surface not less than 3cm is required, and chromium and arsenic in the rice are respectively detected after the rice is mature.

Example 5

Adding the organic fertilizer into the polluted soil at 500 kg/mu, then ploughing the farmland, ensuring the uniform spreading of the organic fertilizer in the organic fertilizer spreading operation process, carrying out rotary tillage on the farmland after the spreading is finished, and adding water for field soaking. Then transplanting 'Jianghao 39', paying attention to the growth vigor of rice, performing pest and disease control on the rice at different periods, and spraying a silicon-rich leaf surface resistance control agent at the heading period and the filling period, wherein 200 ml/mu is sprayed each time. Before the rice grows completely, a flooding measure is adopted, a water layer with the soil surface not less than 3cm is required, and chromium and arsenic in the rice are respectively detected after the rice is mature.

Example 6

Adding the organic fertilizer into the polluted soil at 500 kg/mu, then ploughing the farmland, ensuring the uniform spreading of the organic fertilizer in the organic fertilizer spreading operation process, carrying out rotary tillage on the farmland after the spreading is finished, and adding water for field soaking. Then transplanting 'Liangyou No. 6', paying attention to the growth vigor of the rice, preventing and controlling the diseases and pests of the rice at different periods, and spraying a silicon-rich foliage surface resistance and control agent at the heading period and the filling period, wherein 200 ml/mu is sprayed each time. Before the rice grows completely, a flooding measure is adopted, a water layer with the soil surface not less than 3cm is required, and chromium and arsenic in the rice are respectively detected after the rice is mature.

Examples 1-6 the heavy metal content of rice is shown in Table 1.

TABLE 1 statistical table of heavy metal content of rice

As can be seen from Table 1, in the planting technique according to example 1, the content of heavy metal chromium in rice is 0.40mg/kg, and the content of heavy metal inorganic arsenic in rice is 0.05 mg/kg; in the planting technology related to the embodiment 2, the content of heavy metal chromium in the rice is 0.29mg/kg, and the content of heavy metal inorganic arsenic in the rice is 0.06 mg/kg; in the planting technology related to the embodiment 3, the content of heavy metal chromium in the rice is 0.55mg/kg, and the content of heavy metal inorganic arsenic in the rice is 0.17 mg/kg; in the planting technology related to the embodiment 4, the content of heavy metal chromium in the rice is 0.30mg/kg, and the content of heavy metal inorganic arsenic in the rice is 0.17 mg/kg; in the planting technology related to the embodiment 5, the content of heavy metal chromium in the rice is 0.25mg/kg, and the content of heavy metal inorganic arsenic in the rice is 0.08 mg/kg; example 6 relates to a planting technique in which the content of heavy metal chromium in rice is 0.32mg/kg and the content of heavy metal inorganic arsenic in rice is 0.13 mg/kg.

Examples 1-6 monitoring of rice yield is shown in Table 2.

TABLE 2 statistics table for yield of different varieties of rice

Numbering	Variety of rice	1 Square meter yield (kg)	Water content%	Amounting to mu (kg)
					1	Hubei 18 Zhao Zao	0.64	17.3	412.7
2	Zhongzao 35	0.62	15.2	410.0
					3	Lingshangyou 32	0.68	17.2	439.0
4	Zhongjiazao 17	0.63	14.8	418.5
					5	River morning 39	0.66	21	406.6
6	Liangyou No. 6	0.70	18	447.6

In conclusion, the planting technology can effectively reduce the content of chromium and arsenic in rice, wherein the yield is the highest on the premise that the content of heavy metal in the rice reaches the standard by planting 'Liangyou No. 6'.

It should be understood by those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Although an embodiment of the present invention has been described, it is to be understood that the present invention should not be limited to this embodiment, and variations and modifications can be made by those skilled in the art within the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A planting technology for reducing the contents of chromium and arsenic in rice is characterized by comprising the following steps:

step S4: flooding the rice planting area before the rice grows fully;

2. The planting technology for reducing the content of chromium and arsenic in rice as claimed in claim 1, wherein the organic fertilizer in step S2 is prepared by fermenting the following raw materials: 100 parts of organic bottom material, 0.1-0.2 part of leavening agent and 0.4-0.6 part of rice bran, wherein the organic bottom material comprises the following components in parts by mass: 2-4: 2-4: 1-5: 0.2-0.5 of vinasse, straws, chaffs, mushroom dregs and montmorillonite.

3. The planting technique for reducing the content of chromium and arsenic in rice as claimed in claim 2, wherein the fermentation temperature of the organic fertilizer in the step S2 is not higher than 65 ℃.

4. The planting technique for reducing the content of chromium and arsenic in rice as claimed in claim 1, wherein the row spacing of rice transplanting in the step S3 is 25-35 cm, and the plant spacing is 11-11.7 cm.

5. The planting technology for reducing the chromium and arsenic content in rice as claimed in claim 1, wherein the foliar retarding and controlling agent in the steps S5 and S6 is prepared from the following raw materials in parts by weight: 10-15 parts of urea, 10-20 parts of monopotassium phosphate, 0.5-3 parts of trace elements, 15-25 parts of silicon powder and a plurality of water.

6. The planting technique for reducing the content of chromium and arsenic in rice as claimed in claim 5, wherein the trace elements comprise at least one of calcium, zinc, magnesium, iron and selenium.

7. The planting technology for reducing the content of chromium and arsenic in rice as claimed in claim 5, wherein the particle size of the silicon powder is 10-20 nm.

8. The planting technique for reducing the chromium and arsenic content in rice as claimed in claim 1, wherein the spraying amount of the foliar retarding and controlling agent in the steps S5 and S6 is 160-240 ml/mu, and the foliar retarding and controlling agent is applied to the leaf surface of rice.

9. The planting technique for reducing the chromium and arsenic content in rice as claimed in claim 1, wherein the water layer on the surface of the soil is not less than 3cm when the flooding treatment is performed in step S4.