CN111869356A

CN111869356A - Agricultural gypsum powder and method for improving barren soil by using same

Info

Publication number: CN111869356A
Application number: CN202010724626.2A
Authority: CN
Inventors: 杨兴; 李泽钢; 何信周; 黄巧玲; 徐立斌; 陈尚伟; 朱国良; 周灵; 罗通; 陈亦苏; 廖昶; 聂晓鹏; 崔晨; 李洪青; 陈秋如; 熊卉芹
Original assignee: Guizhou Lindu Garden Engineering Co ltd; GUIZHOU ZHONGJIAN ARCHITECTURAL SCIENCE DESIGN INSTITUTE CO LTD
Current assignee: Guizhou Lindu Garden Engineering Co ltd; GUIZHOU ZHONGJIAN ARCHITECTURAL SCIENCE DESIGN INSTITUTE CO LTD; Guizhou China Construction Architecture Research and Design Institute Co Ltd
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2020-11-03

Abstract

The invention belongs to the technical field of soil improvement, and particularly relates to agricultural gypsum powder and a method for improving barren soil by using the same, wherein the agricultural gypsum powder is used for improving the barren soil, and the improvement method comprises the following steps: 1) treating the barren soil by using a soil bactericide in one of spraying, irrigating or mixing modes; 2) spreading the crushed straws and the agricultural gypsum powder on the surface layer of the soil, watering until the crushed straws are wet, and ploughing; 3) spreading animal waste and a decomposition agent on the surface layer of the soil and carrying out deep ploughing; 4) decomposing for 30-60 days, ploughing for 2-3 times during the decomposing period, and simultaneously irrigating until the improved soil is wet; fully utilizes the industrial byproduct phosphogypsum, improves the barren soil by utilizing nutrient elements contained in the phosphogypsum, and simultaneously prevents the pollution of the phosphogypsum to the barren soil.

Description

Agricultural gypsum powder and method for improving barren soil by using same

Technical Field

The invention belongs to the technical field of soil improvement, and particularly relates to agricultural gypsum powder and a method for improving barren soil by using the same.

Background

Gypsum-based industrial solid wastes with high yield,The gypsum has the characteristics of more impurities and the like, so that the application range of the gypsum is greatly limited, and at present, the main application of the gypsum is embodied in building materials, cement products, chemical products, agriculture and other aspects; in agricultural application, the phosphogypsum is used most frequently, and contains elements such As phosphorus, calcium, magnesium, iron, silicon, sulfur and the like required by crops, so that mineral elements in soil can be supplemented, the soil environment is improved, the fertilizing amount is reduced, hard shells on the surface layer of the soil are eliminated, the viscosity of the soil is reduced, the permeability of the soil is increased, and crop diseases are prevented, so that the phosphogypsum is mainly used As a saline-alkali soil conditioner and fertilizer, but the phosphogypsum is acidic and has single nutrient component and contains heavy metal and other pollution, the agricultural utilization of the phosphogypsum is greatly limited, meanwhile, the agricultural ecological pollution risk of the phosphogypsum, the fluorine pollution risk, the heavy metal pollution risk, the radionuclide pollution risk and the like are pointed out in the document' environmental safety risk of phosphogypsum agriculture 67%, 63%, 40% and 20%, respectively; the leaching concentration of Hg, Cd, Pb, Ni, Cr and Be is detected to exceed the IV-V water quality standard in the underground water quality standard (GB/T14848-2017), the risk of heavy metal pollution of soil and water exists, and about 20-40% of fluorine in phosphate ore enters phosphogypsum. The total fluorine content and the water-soluble fluorine content in the phosphogypsum are higher (the highest values are 20400 and 7500 mg/kg respectively)^-1) The ratio of the critical value of soil perfluoro and water-soluble fluorine exceeding the critical value of the soil perfluoro and the water-soluble fluorine exceeding the critical value of the soil in the area where the Chinese difluoro diseases occur is 89 percent and 100 percent respectively; the leaching concentration of the extract is detected to be far beyond the V-type water quality standard of underground water quality standard (GB 14848-2017), and the extract concentration of the extract is partially beyond the leaching limit (100 mg. L) of hazardous waste identification standard-leaching toxicity identification (GB 5085.3-2007)^-1) The risk of soil and water fluorine pollution exists, and the like, which fully indicates that the phosphogypsum cannot be directly used in the agricultural field.

In the aspect of agriculture, due to the influences of excessive planting, water and soil loss, excessive fertilizer application and the like, fertile soil in China is less and less, the barren soil is more and more, the barren soil is easy to harden, the permeability is poor, the fertilizer efficiency is low, the tiltability is poor, gypsum is rich in soil required elements, such as sulfur, calcium, silicon, magnesium, iron, sodium, potassium, phosphorus and other beneficial components, and a proper amount of modifier is doped in the gypsum to modify the barren soil to cultivate landscaping crops and greening engineering.

Disclosure of Invention

The invention provides agricultural gypsum powder and a method for improving barren soil by using the same, aiming at the defects of the prior art.

The method is realized by the following technical scheme:

an agricultural gypsum powder, the preparation method comprises:

1) emulsification: crushing gypsum to 100 meshes, immersing gypsum powder into industrial alcohol for 20-30min, adding a cellulose solution with the mass concentration of 20-40% and an emulsifier, and performing ultrasonic dispersion for 20-30min under the conditions of the power of 100-;

2) carbonizing: putting the gypsum powder obtained in the step 1) into a tube furnace, heating to 200 ℃ under the protection of nitrogen, and preserving heat for 45-60 min;

3) grinding: mixing and grinding the gypsum powder obtained in the step 2) and a surfactant until the mixture is sieved by a 600-mesh sieve, and then carrying out heat treatment for 15-25min in a saturated steam environment.

The emulsifying agent comprises the following components in parts by weight in an emulsifying system: 40-50 parts of gypsum powder, 50-70 parts of industrial alcohol, 4-7 parts of cellulose solution and 1.3-2.5 parts of emulsifier.

The gypsum at least comprises phosphogypsum, and the mass percent of the phosphogypsum is more than or equal to 90 percent.

Further preferably, the gypsum is a combination of phosphogypsum and titanium gypsum.

The emulsifier is tween-80.

The cellulose solution contains 1-5% of phase-change material by mass.

The phase-change material is any one or a combination of a plurality of palm alcohol, palmitic acid and capric acid.

The grinding is carried out, wherein the grinding system comprises the following components in parts by weight: 40-50 parts of gypsum powder and 1-3 parts of surfactant.

The surfactant is tween-20.

The agricultural land plaster is used for improving barren soil.

The agricultural gypsum powder improved barren soil is used as a nursery seedling culture substrate.

The method for improving the barren soil by using the agricultural land plaster comprises the following steps:

1) treating the barren soil by using a soil bactericide in one of spraying, irrigating or mixing modes;

2) spreading the crushed straws and the agricultural gypsum powder on the surface layer of the soil, watering until the crushed straws are wet, and ploughing;

3) spreading animal waste and a decomposition agent on the surface layer of the soil and carrying out deep ploughing;

4) decomposing for 30-60 days, ploughing for 2-3 times during the decomposing period, and simultaneously irrigating until the improved soil is wet.

The soil bactericide is a tobacco waste modified material.

The manufacturing method of the tobacco waste modified material comprises the following steps:

firstly, according to the water-material ratio of equal mass ratio, soaking tobacco waste in aqueous solution at 40-60 ℃ for 3-5h, and air-drying;

secondly, adding the air-dried tobacco waste into a microwave kettle containing ammonia water with the mass concentration of 1-5% according to the material-liquid ratio of equal mass ratio, and carrying out microwave treatment for 10-20min under the power of 220-300W.

In a system for improving barren soil by using agricultural gypsum powder, the materials are as follows in parts by weight: 50-100 parts of barren soil, 5-50 parts of agricultural gypsum powder, 5-50 parts of straw, 1-20 parts of animal manure, 0.2-5 parts of a decomposition agent and 0.5-5 parts of a soil bactericide.

Has the advantages that:

firstly, the industrial byproduct phosphogypsum is fully utilized, nutrient elements contained in the phosphogypsum are utilized to improve the barren soil, and meanwhile, the pollution of the phosphogypsum to the barren soil is prevented; what is the same technical principle of preventing soil contamination in the patent? Is the amount of incorporation low or surface modification of cellulose?

The gypsum powder has the effects of inhibiting bacteria, supplying nutrients, regulating humidity and temperature, has better freezing and thawing resistance and acid rain erosion resistance, can be used for nursery seedling culture, is used as an agricultural insecticide and a bacteriostatic agent, does not pollute soil when being applied to the soil with heavy metal dissolution rate, and meets the requirements of soil environmental quality standard (GB 15618-1995) after being applied to the soil for a long time. The concrete points are as follows:

1) the gypsum can be sterilized by soaking in alcohol, so that the decomposition and damage of microorganisms to cellulose are avoided;

2) the cellulose can form a porous film on the surface of the gypsum in the emulsification process, which is beneficial to controlling the migration condition of elements in the gypsum and simultaneously carrying out surface modification to prevent the gypsum from hydrating; the phase change material is added into the emulsification system, so that the freeze-thaw erosion resistance and the heat preservation effect of the gypsum powder are improved, the heat clearing effect of the gypsum is not influenced, and the temperature of a culture matrix can be reduced and the seedlings are prevented from being burnt when the temperature is high in summer; at low temperature, the gypsum powder has a heat preservation effect, and can avoid the cold injury and the freezing injury of seedlings; the poly-dopamine is added into the emulsifying system to be capable of cooperating with the gypsum, so that the bacteriostatic ability is enhanced, and meanwhile, the acid rain erosion resistance can be improved.

3) The polydopamine can be carbonized in the carbonization process, part of pores in the gypsum can be filled, carbon atoms are solidified in the pores, and the migration of free harmful substances in the gypsum is avoided;

4) tween-80 is used as a surfactant, so that the gypsum powder has flexibility, the surface smoothness and the fineness of the gypsum powder can be improved, the gypsum powder is favorable for quick grinding, and the grinding efficiency is improved by 5-8% compared with the conventional method; tween-20 is used as an emulsifier, and can form good affinity with a surfactant, so that a porous membrane can be formed on the surface.

5) The heat treatment of saturated steam can make the cellulose slightly expand and soften, and the softness of the gypsum powder is increased, so that the gypsum powder is beneficial to intermittent water storage when being used in a nursery.

6) The gypsum at least comprises titanium gypsum and citric acid gypsum, and the cellulose can form good coating on the gypsum surface under the catalytic action of residual titanium element in the titanium gypsum by utilizing the catalytic action of the residual citrate of the citric acid gypsum, so that the effect of preventing the migration and dissolution of pollutants in the gypsum is improved.

Secondly, the soil bactericide made of tobacco waste is added to kill germs and pests in the soil and improve the disease resistance or the tillering property of the soil;

the tobacco waste is soaked by water, so that the vascular bundles of the tobacco waste are swelled, the effective components in the tobacco waste provide migration space, the ammonia water is used for activating the tobacco waste in cooperation with the microwave, the light absorption capacity of the tobacco waste is enhanced, the effective components of the tobacco waste can be slowly released in the using process, and the long-acting nourishing effect is achieved. Therefore, the tobacco waste has beneficial insecticidal and bacteriostatic effects and humidity regulating effects, and is beneficial to nursery seedling.

Thirdly, the straw and the animal manure are fully utilized, and are recycled and valuably utilized, which is beneficial to the improvement of the natural environment.

Fourthly, precious land resources are fully utilized, the improved barren soil is used for nursery cultivation and greening engineering, and the problem of lack of planting soil is solved.

Detailed Description

The following is a detailed description of the embodiments of the present invention, but the present invention is not limited to these embodiments, and any modifications or substitutions in the basic spirit of the embodiments are included in the scope of the present invention as claimed in the claims.

Example 1

A method for improving barren soil by using agricultural gypsum powder comprises the following materials in parts by weight in an improvement system: 50 parts of barren soil, 5-50 parts of agricultural gypsum powder, 5-50 parts of straws, 1 part of animal manure, 0.2 part of a decomposition agent and 0.5 part of a soil bactericide, and the improvement method comprises the following steps:

4) decomposing for 30 days, ploughing for 2 times during the decomposing period, and simultaneously irrigating until the improved soil is kept moist;

the preparation method of the agricultural gypsum powder comprises the following steps:

1) emulsification: crushing phosphogypsum to pass through a 100-mesh sieve, immersing the phosphogypsum powder into industrial alcohol for 20min, adding a cellulose solution with the mass concentration of 20% and an emulsifier, and performing ultrasonic dispersion for 20min under the conditions of the power of 100W and the temperature of 55 ℃; the emulsion comprises the following components in parts by weight in an emulsion system: 40 parts of phosphogypsum powder, 50 parts of industrial alcohol, 4 parts of cellulose solution and 801.3 parts of tween-801; the cellulose solution contains 1% of phase-change material by mass fraction; the phase change material is palmitol;

3) grinding: mixing and grinding the phosphogypsum powder obtained in the step 2) and tween-20 until the mixture is sieved by a 600-mesh sieve, and then carrying out heat treatment for 15-25min in a saturated steam environment; the grinding system comprises the following components in parts by weight: 40-50 parts of phosphogypsum powder and 201-3 parts of tween-201;

the soil bactericide is a tobacco waste modified material;

soaking tobacco waste in an aqueous solution at 60 ℃ for 5 hours according to a water-material ratio of equal mass ratio, and air-drying;

secondly, adding the air-dried tobacco waste into a microwave kettle containing ammonia water with the mass concentration of 5% according to the material-liquid ratio of equal mass ratio, and carrying out microwave treatment for 20min under the power of 300W.

Example 2

A method for improving barren soil by using agricultural gypsum powder comprises the following materials in parts by weight in an improvement system: 100 parts of barren soil, 50 parts of agricultural gypsum powder, 50 parts of straws, 20 parts of animal wastes, 5 parts of a decomposition agent and 5 parts of a soil bactericide, and the improvement method comprises the following steps:

4) decomposing for 60 days, ploughing for 3 times during the decomposing period, and simultaneously irrigating until the improved soil is kept moist;

1) emulsification: crushing gypsum to 100 meshes, immersing gypsum powder in industrial alcohol for 30min, adding 40% cellulose solution and emulsifier, and ultrasonically dispersing at the power of 130W and the temperature of 65 ℃ for 30 min; the emulsion comprises the following components in parts by weight in an emulsion system: 45 parts of phosphogypsum, 5 parts of citric acid gypsum, 70 parts of industrial alcohol, 7 parts of cellulose solution and 802.5 parts of tween-802.5; the cellulose solution contains 5% of phase-change material by mass fraction; the phase change material is capric acid;

2) carbonizing: putting the gypsum powder obtained in the step 1) into a tube furnace, heating to 200 ℃ under the protection of nitrogen, and keeping the temperature for 60 min;

3) grinding: mixing and grinding the gypsum powder obtained in the step 2) and tween-20 until the mixture is sieved by a 600-mesh sieve, and then carrying out heat treatment for 25min in a saturated steam environment; the grinding system comprises the following components in parts by weight: 45 parts of phosphogypsum, 5 parts of citric acid gypsum and 203 parts of tween-203;

the soil bactericide is a tobacco waste modified material;

soaking tobacco waste in an aqueous solution at 40 ℃ for 3 hours according to a water-material ratio of equal mass ratio, and air-drying;

secondly, adding the air-dried tobacco waste into a microwave kettle containing ammonia water with the mass concentration of 1% according to the material-liquid ratio of equal mass ratio, and carrying out microwave treatment for 10min under the power of 220W.

Example 3

A method for improving barren soil by using agricultural gypsum powder comprises the following materials in parts by weight in an improvement system: 75 parts of barren soil, 25 parts of agricultural gypsum powder, 20 parts of straws, 10 parts of animal manure, 3 parts of a decomposition agent and 2 parts of a soil bactericide, and the improvement method comprises the following steps:

4) ploughing for 45 days, ploughing for 3 times during the ploughing period, and simultaneously irrigating until the improved soil is kept moist;

1) emulsification: crushing phosphogypsum to pass through a 100-mesh sieve, soaking the phosphogypsum powder in industrial alcohol for 25min, adding a cellulose solution with the mass concentration of 30% and Tween-80, and performing ultrasonic dispersion for 25min under the conditions of the power of 120W and the temperature of 60 ℃; the emulsion comprises the following components in parts by weight in an emulsion system: 45 parts of gypsum powder, 60 parts of industrial alcohol, 5 parts of cellulose solution and 801.8 parts of tween-water; the cellulose solution contains 3% of phase-change material by mass fraction; the phase change material is palmitic acid;

2) carbonizing: placing the phosphogypsum powder obtained in the step 1) in a tube furnace, heating to 200 ℃ under the protection of nitrogen, and keeping the temperature for 55 min;

3) grinding: mixing and grinding the phosphogypsum powder obtained in the step 2) and tween-20 until the mixture is sieved by a 600-mesh sieve, and then carrying out heat treatment for 20min in a saturated steam environment; the grinding system comprises the following components in parts by weight: 45 parts of phosphogypsum powder and 202 parts of tween-tween;

the soil bactericide is a tobacco waste modified material;

soaking tobacco waste in an aqueous solution at 50 ℃ for 4 hours according to the water-material ratio of equal mass ratio, and air-drying;

secondly, adding the air-dried tobacco waste into a microwave kettle containing ammonia water with the mass concentration of 3% according to the material-liquid ratio of equal mass ratio, and carrying out microwave treatment for 15min under the power of 260W.

Example 4

A method for improving barren soil by using agricultural gypsum powder comprises the following materials in parts by weight in an improvement system: 100 parts of barren soil, 10 parts of agricultural gypsum powder, 7 parts of straws, 5 parts of animal wastes, 0.2 part of a decomposition agent and 1 part of a soil bactericide, and the improvement method comprises the following steps:

4) decomposing for 50 days, ploughing for 2 times during the decomposing period, and simultaneously irrigating until the improved soil is kept moist;

1) emulsification: crushing gypsum to 100 meshes, immersing gypsum powder in industrial alcohol for 25min, adding a cellulose solution with the mass concentration of 30% and Tween-80, and performing ultrasonic dispersion at the power of 110W and the temperature of 60 ℃ for 25 min; the emulsion comprises the following components in parts by weight in an emulsion system: 47 parts of phosphogypsum powder, 3 parts of titanium gypsum powder, 50 parts of industrial alcohol, 6 parts of cellulose solution and 801.3 parts of tween-801; the cellulose solution contains 1-5% of phase-change material by mass; the phase-change material is a composition of palm alcohol, palmitic acid and capric acid in equal mass ratio;

2) carbonizing: putting the gypsum powder obtained in the step 1) into a tube furnace, heating to 200 ℃ under the protection of nitrogen, and keeping the temperature for 55 min;

3) grinding: mixing and grinding the gypsum powder obtained in the step 2) and tween-20 until the mixture is sieved by a 600-mesh sieve, and then carrying out heat treatment for 20min in a saturated steam environment; the grinding system comprises the following components in parts by weight: 47 parts of phosphogypsum powder, 3 parts of titanium gypsum powder and 201 parts of tween-201;

the soil bactericide is a tobacco waste modified material;

firstly, soaking tobacco waste in an aqueous solution at 50 ℃ for 4.5 hours according to the water-material ratio of equal mass ratio, and air-drying;

secondly, adding the air-dried tobacco waste into a microwave kettle containing ammonia water with the mass concentration of 1% according to the material-liquid ratio of equal mass ratio, and carrying out microwave treatment for 12min under the power of 280W.

Examples 5 to 9

On the basis of example 3, gypsum selection is shown in table 1;

TABLE 1

Comparative example 1

On the basis of example 3, no phase change material was used.

Comparative example 2

On the basis of example 3, no tobacco waste modifying material was used as a soil fungicide.

Comparative example 3

On the basis of example 4, no surfactant was used.

Comparative example 4

On the basis of example 1, no carbonization was carried out.

Comparative example 5

On the basis of example 2, no saturated steam heat treatment was carried out.

Comparative example 6

On the basis of the embodiment 4, the manufacturing method of the tobacco waste modified material comprises the following steps:

soaking the tobacco waste in an aqueous solution at 50 ℃ for 4.5h according to the water-material ratio of equal mass ratio, and air-drying.

Test example 1 bacteriostatic test

1. Test materials: potato virus-free seedlings;

test-tube plantlet growth medium: MS culture medium

2. And (3) experimental design: each treatment was repeated for 5 groups of 10 bottles, each group being charged with the landplaster of examples 3, 9-14 and comparative examples 1-2, respectively, in an amount of 1mg/g per bottle; counting the number of polluted bottles and the number of germinated bottles in a callus induction stage and a propagation stage by taking gypsum powder not added as a control group;

3. the results are shown in Table 2;

TABLE 2

Test example 2 Effect test on control of Gossypium barbarum

1. Test work: medlar, variety: number 1 of Chaihu;

soil conditions: the soil quality is chestnut calcium soil, the pH value is 8.4, the test field surface is smooth, the soil fertility is consistent, and the irrigation condition is good; the tree age of the medlar is 5a, the plant spacing is 110cm, the row spacing is 220cm, and each 667m²About 280 plants;

2. and (3) experimental design: spraying 10 Lycium chinense trees in each group, and performing no treatment on blank control group at a ratio of 2.5L/hm²Spraying 50 times of diluent of 5% pyrethrin emulsifiable solution, and spraying gypsum powder on the surface of the experimental group according to the amount of 1 kg/mu, wherein the results are shown in table 3;

3. investigation and statistics

And (3) drug effect investigation: selecting 5 Chinese wolfberry trees in each cell by adopting a 5-point sampling method, selecting 1 branch in east, south, west, north and middle 5 directions of each tree respectively, marking by hanging tags, investigating and recording the number of cotton aphid mouths on branches 20cm inwards from the tail ends of the branches. The tests are investigated for 4 times, the population base number is investigated before the pesticide is applied, and the residual population number on the branches is investigated 7 days after the pesticide is applied;

safety investigation: in the test process, observing whether different treatment concentrations of all the medicaments produce phytotoxicity or other abnormal phenomena on the medlar;

and (3) calculating the drug effect: after the investigation data are collated, the survival rate of insect population and the correction control effect are respectively calculated;

oral cavity decline rate (%) [ (number of pre-control insects-number of residual insects after control)/number of pre-control insects ] × 100

The corrected control effect (%) (control population reduction rate-treatment population reduction rate)/(1-control population reduction rate) ] × 100

4. The control effect results of each group of the Chinese wolfberry cotton aphids are shown in table 3;

TABLE 3

Experimental group	Example 1	Example 2	Example 4	Control group
					Prevention effect	67.5％	66.3％	69.2％	70.1％
Experimental group	Comparative example 3	Comparative example 5	Comparative example 6
					Prevention effect	54.1％	42.6％	35.9％

Experimental example 3 tomato planting Effect

1. Test work: the tomatoes are stone dunes 208;

2. seedling raising substrate: respectively sterilizing fermented cow dung, vermiculite, perlite and gypsum powder for 2 hours by high-pressure steam at 115 ℃ according to equal mass ratio, and mixing to prepare a seedling culture substrate;

3. the planting method comprises the following steps: utilizing a 72-hole seedling raising tray to carry out tomato seedling raising, transplanting 9 tomato seedlings in each cell, wherein the fertilization standard is 15g of urea and 30g of monoammonium phosphate per square meter, and top dressing is carried out for 2 times during the growth period, and 23g of urea per square meter is carried out each time; the phosphogypsum is deeply applied by 10-15cm with the application standard of 1.5kg/m²(ii) a The furfural residue is mixed with 0-5cm surface soil, and the application standard is 230g/m²(ii) a The technical control of temperature, humidity and the like is referred to greenhouse tomato seedling technology (Wangliang published in 2020);

4. detecting items: measuring the soluble solid content of the tomato fruits by using a WZ-102 handheld glucometer, measuring titratable acid by using a NaOH comprehensive titration method, defining the sugar-acid ratio as the soluble solid content/titratable acid, measuring the vitamin C content by using a 2, 6-dichloroindophenol method, and measuring the nitrate content by using a spectrophotometric method;

5. and (3) experimental design: the seedling raising substrate without gypsum powder is taken as a control group, and the test groups are respectively example 5-8, comparative example 1, comparative example 4 and comparative example 6;

6. results display

The results of the yield and fruit quality measurements are shown in table 4;

TABLE 4

The inventor carries out disease and pest attack investigation and statistics on tomato seedlings and seedling stages, and the result shows that: compared with a control group, damping-off and damping-off of the examples and the comparative example are obviously reduced (the reduction rate is 88-95%), and meanwhile, the hazard rate of pests such as whiteflies, cotton bollworms, aphids and the like is also obviously reduced (the reduction rate is 73-85%); the disease and pest phenomena of examples 5 to 8 were less than those of comparative examples 1, 4 and 6, and in conclusion, examples 5 to 8 were not significant in spite of weak occurrence of disease and pest, and had weak effects on the yield and quality of fruits.

The inventors also performed the following tests: seedling culture is carried out under the conditions of 32-35 ℃ (high temperature) and 18-23 ℃ (low temperature) by adopting the mixed matrixes prepared from the gypsum powder of examples 5-8, the mixed matrixes prepared from the gypsum powder of comparative examples 1, 4 and 6 and the mixed matrixes of a control group, wherein the yield of the control group is reduced at two temperatures, the reduction rates are respectively 9.3% and 5.1%, the yield of the comparative example 1 does not show a remarkable reduction (the reduction rate is about 0.5%) at the high temperature, and the yield is remarkably reduced (5.7%) at the low temperature; the groups of examples 5 to 8 and comparative examples 4 and 6 showed no significant decrease in yield at high or low temperatures, with a rate of decrease of 0.3% or less.

Test example 4

The gypsum powders of examples 1 to 4 and comparative example 1, comparative example 2 and comparative example 4 were examined by using an apparatus and method for the migration characteristics of heavy metal components in desulfurized gypsum in column leaching mode (published by wanshaozuo et al in 2017), and the results showed that: the maximum leaching rates of the elements in examples 1-4 were as follows: cr is less than or equal to 1.1 percent, As is less than or equal to 5.6 percent, Ni is less than or equal to 7.3 percent, Pb is less than or equal to 7.0 percent, Hg is less than or equal to 2.7 percent, and the maximum leaching rates of the elements in comparative examples 1, 2 and 4 are As follows: cr2.3-3.0%, As9.5-11.2%, Ni 10-10.9%, Pb12.1-14.5%, Hg4.5-5.1%, from which: the heavy metal leaching rate of the gypsum powder treated by the method is low.

Claims

1. The agricultural gypsum powder is characterized in that the preparation method of the agricultural gypsum powder comprises the following steps:

2. The agricultural land plaster of claim 1, wherein the gypsum comprises at least phosphogypsum, and the mass percentage of the phosphogypsum is more than or equal to 90%.

3. The agricultural land plaster of claim 1, wherein the emulsifier is tween-80.

4. The agricultural land plaster of claim 1, wherein the cellulose solution contains 1-5% by mass of the phase change material.

5. The agricultural land plaster of claim 1, wherein the surfactant is tween-20.

6. An agricultural land plaster as claimed in any one of claims 1 to 5 for improving poor soils.

7. The agricultural land for improving barren soil by using the agricultural land plaster as claimed in claim 6, wherein the materials comprise the following components in parts by weight: 50-100 parts of barren soil, 5-50 parts of agricultural gypsum powder, 5-50 parts of straw, 1-20 parts of animal manure, 0.2-5 parts of a decomposition agent and 0.5-5 parts of a soil bactericide.

8. The method for improving infertile soil by using agricultural land plaster as claimed in claim 6 or 7, comprising the steps of:

9. The method of improving poor soil with agricultural land plaster as claimed in claim 8, wherein the soil fungicide is a tobacco waste modification material.

10. The method for improving the poor soil by using the agricultural land plaster as claimed in claim 9, wherein the tobacco waste modified material is prepared by the following steps: