Organic fertilizer suitable for newly-reclaimed terraced field and preparation method of organic fertilizer

Abstract

The invention relates to an organic fertilizer suitable for a newly-reclaimed terrace and a preparation method of the organic fertilizer, and belongs to the technical field of biological fertilizers. The treated copper-nickel sulfide ore smelting slag is compounded with the compound bacteria liquid, the animal waste and the red mud-based complexing agent to prepare the soil organic fertilizer. The method creatively realizes full utilization of a silicate matrix and metal elements in the copper-nickel sulfide ore smelting slag, has a nutrient slow release function, realizes improvement of soil fertility through a flora-carrier synergistic effect, finally realizes a soil conditioning effect, and is especially suitable for soil structure improvement and rapid fertilization of newly-reclaimed terraced fields.

Description

Technical Field

[0001] The invention belongs to the technical field of biological fertilizers, and in particular relates to an organic fertilizer suitable for newly reclaimed terraced fields and a preparation method thereof. Background Art

[0002] Terraces are a widely used land use method in the world, especially in hilly and mountainous areas. They are not only an effective means to prevent soil erosion and maintain ecological balance, but also an important strategy to ease the contradiction between people and land, improve land use efficiency, and stabilize production. The rice terraces in Asia and the vineyard terraces in Europe and America play an irreplaceable role in the world with their unique landscape value and efficient agricultural production functions. However, during the construction process, the newly reclaimed terraces suffered mechanical damage, the soil structure was damaged, the raw soil was exposed, and the physical and chemical properties of the soil deteriorated, resulting in a lack of organic matter in the newly reclaimed terraces, poor tillage layer structure, and weak water and fertilizer storage capacity. These problems seriously restricted the production potential and stress resistance and stable production capacity of the newly reclaimed terraces.

[0003] Traditional soil fertilization methods, such as applying organic fertilizers or chemical fertilizers, can improve soil fertility to a certain extent, but they are usually slow to take effect, high in cost, and low in resource utilization, making it difficult to meet the urgent need of modern agriculture for rapid improvement of soil productivity. Therefore, exploring efficient and rapid soil fertilization technologies is of vital importance to improving the productivity of newly cultivated terraces, ensuring food security, and promoting sustainable agricultural development. Exogenous carbon input is an effective way to improve soil fertility. It mainly refers to the introduction of organic carbon sources into the soil through artificial means, such as crop straw, livestock and poultry manure, and organic fertilizers. These exogenous carbons can directly increase soil nutrients and can also be absorbed and utilized by soil microorganisms to promote microbial growth and turnover. The continuous input of exogenous organic materials, through the metabolic secretion of microorganisms and the transformation of residues, eventually becomes an important component of stable organic matter. Therefore, sufficient exogenous organic matter input is a necessary condition for the large-scale accumulation of soil organic matter.

[0004] However, there are significant differences in the effects of different bio-organic materials in promoting soil fertility. Especially in the special land use type of Xinken Terraces, the nutrient content of existing bio-organic fertilizers is relatively low, and the nutrient release rate and utilization rate are not ideal. Therefore, further research on improving the types and preparation methods of bio-organic fertilizers, increasing the nutrient content in bio-organic fertilizers to make them better suitable for Xinken Terraces, and improving the soil nutrients, organic carbon components and enzyme activity of Xinken Terraces are urgent practical needs. Summary of the invention

[0005] In view of the technical problems existing in the prior art, the purpose of the present invention is to provide an organic fertilizer suitable for newly reclaimed terraced fields and a preparation method thereof.

[0006] The purpose of the present invention can be achieved through the following technical solutions: The present invention provides a method for preparing an organic fertilizer suitable for newly cultivated terraced fields, comprising the following steps: (1) mixing a certain amount of copper-nickel sulfide ore smelting slag with concentrated sulfuric acid, leaching the metal components in the copper-nickel sulfide ore smelting slag to obtain a leaching solution and leaching slag, drying the leaching slag, and uniformly mixing the dried leaching slag with a certain amount of polyacrylic acid and potassium chloride particles, pressing and forming, and solidifying. The obtained block is calcined in an inert atmosphere, washed, and a micron / nanoporous structure carrier is obtained; (2) taking a certain amount of leachate a and mixing it with water to obtain a metal solution A, using the metal solution A to impregnate the micron / nanoporous structure carrier prepared in step (1), drying, and calcining the dried carrier under an inert atmosphere; (3) uniformly mixing the product prepared in step (2) with the composite bacterial solution, and then fully mixing the obtained mixture with a certain amount of animal feces to obtain a fertilizer matrix; (4) A certain amount of leachate b is mixed with water to obtain a metal solution B, and the fertilizer matrix prepared in step (3) is impregnated with the metal solution B, and then dried. The dried matrix is ​​evenly mixed with the composite agent to obtain an organic fertilizer.

[0007] Furthermore, the composite bacterial liquid in step (3) is obtained by mixing Azospirillum brasiliensis and Pantoea affinis liquid, wherein the mass ratio of Azospirillum brasiliensis to Pantoea affinis is 1:(1-2), and the total mass of the bacterial species in the composite bacterial liquid is 3-20% of the mass of the product prepared in step (2).

[0008] Furthermore, the composite agent in step (4) is obtained by mixing red mud, Bacillus subtilis and quicklime, wherein the mass ratio of red mud, Bacillus subtilis and quicklime is (2-5): (1-3): (2-5), and the mass ratio of the composite agent to the dried matrix prepared in step (4) is 1: (10-100).

[0009] Furthermore, in step (1), the calcination temperature is 500-800° C., the inert atmosphere is one of nitrogen and argon, and the potassium chloride particles are obtained by passing through a 200-mesh sieve.

[0010] Furthermore, in step (2), the volume ratio of the leachate a to the leachate in step (1) is 1:(5-20), and the volume ratio of the leachate a to water is 1:(10-50).

[0011] Furthermore, in step (3), the mass ratio of the mixture to the animal feces is 1:(5-30).

[0012] Furthermore, in step (4), the volume ratio of the leachate b to the leachate in step (1) is 1:(5-20), and the volume ratio of the leachate b to water is 1:(10-50).

[0013] The present invention also provides an organic fertilizer suitable for newly reclaimed terraced fields, and the organic fertilizer is prepared by adopting the above-mentioned preparation method.

[0014] The invention also provides a method for rapid soil fertilization, which adopts the organic fertilizer.

[0015] The present invention does not need to introduce new metal components in the process of preparing organic fertilizers, fully utilizes various components in the copper-nickel sulfide ore smelting slag, recovers metal elements in the copper-nickel sulfide ore smelting slag, and makes the metal-loaded organic fertilizer become a slow-release source of trace nutrients for loaded bacteria and crops. Compared with other wastes such as slag, the specific metal composition and other factors in the copper-nickel sulfide ore smelting slag enhance the activity of the loaded bacterial flora. The present invention improves the utilization rate of the copper-nickel sulfide ore smelting slag and realizes the solid waste resourceization of the smelting slag.

[0016] The micron / nano pore structure carrier prepared by the present invention enables the metal load layer to play a micronutrient slow-release function, and potassium chloride is selected as a pore-forming agent, which reduces the secondary pollution of the soil caused by the introduction of chemical reagents in the preparation process of organic fertilizers, and the residual potassium chloride can still be used as a micronutrient slow-release source. At the same time, the biological nitrogen fixation and other effects of the flora in the organic fertilizer and the physical adsorption of the micron / nano pore structure carrier form a synergistic effect. The composite structure prepared by the present invention is more suitable as a host of microorganisms, and the biological compatibility of the carrier is improved.

[0017] The present invention finds that by simultaneously introducing organic fertilizers using Azospirillum brasiliensis, Pantoea ananas and Bacillus subtilis, in addition to the mutual provision of energy substances between the bacterial species, in an organic fertilizer system composed of a specific structural carrier and a specific metal, the bacterial community recorded in the present invention can make the organic fertilizer have better fertility and higher nitrogen fixation efficiency than organic fertilizers obtained by combinations of other bacterial species; the organic fertilizer of the present invention acts on the soil to increase the nutrient content of the soil and the crop yield, and can increase the enzyme activity in the soil.

[0018] Beneficial effects of the present invention: 1. The present invention prepares soil organic fertilizer containing a porous matrix, and the silicate matrix in the smelting slag is efficiently converted through high-temperature phase change reconstruction, while metal elements such as Cu and Ni are effectively recovered. The prepared porous matrix has both a carrier skeleton and a slow-release function, which can replace traditional carrier materials and realize high-value-added resource utilization of waste.

[0019] 2. The organic fertilizer in the present invention can increase the organic matter and nitrogen content of the soil, and the composite bacterial solution can promote the decomposition of organic matter and the effectiveness of nutrients, promote soil improvement, and thus facilitate the improvement of soil productivity; at the same time, the organic fertilizer can significantly increase the soil nutrient content and soil enzyme activity, promote the improvement of soil fertility, and ultimately achieve the effect of soil conditioning. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Unless otherwise specified, the raw materials and equipment used in the embodiments of the present invention are raw materials and equipment from conventional sources in the art. The endpoints and any values ​​of the scope disclosed in this article are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, between the endpoint values ​​of each scope, between the endpoint values ​​of each scope and a separate point value, and between separate point values, one or more new numerical ranges can be combined with each other, and these numerical ranges should be considered as specifically disclosed in this article.

[0022] Example 1

[0023] An organic fertilizer suitable for newly cultivated terraced fields, the organic fertilizer is prepared by the following preparation method: comprising the steps of: (1) A certain amount of copper-nickel sulfide ore smelting slag is mixed with concentrated sulfuric acid, and after the metal components in the copper-nickel sulfide ore smelting slag are leached out, a leaching solution and leaching slag are obtained, the leaching slag is dried, and the dried leaching slag is mixed with a certain amount of polyacrylic acid and potassium chloride particles passed through a 200-mesh sieve, pressed into shape, and solidified. The obtained block is calcined in an argon atmosphere at a calcination temperature of 600° C., and washed to obtain a micron / nanoporous structure carrier; (2) taking a certain amount of leachate a and mixing it with water to obtain a metal solution A, using the metal solution A to impregnate the micron / nanoporous structure carrier prepared in step (1), drying, and calcining the dried carrier under an inert atmosphere; the volume ratio of the leachate a to the leachate in step (1) is 1:10, and the volume ratio of the leachate a to water is 1:30; (3) The product prepared in step (2) is mixed evenly with the composite bacterial liquid, and the obtained mixture is then fully mixed with a certain amount of animal feces to obtain a fertilizer matrix; the composite bacterial liquid is obtained by mixing Azospirillum brasiliensis and Pantoea pineapple liquid, wherein the mass ratio of Azospirillum brasiliensis to Pantoea pineapple is 1:1, and the total mass of the bacterial species in the composite bacterial liquid is 15% of the mass of the product prepared in step (2). The mass ratio of the mixture to the animal feces is 1:25; (4) taking a certain amount of leachate b and mixing it with water to obtain a metal solution B, using the metal solution B to impregnate the fertilizer substrate prepared in step (3), drying, and evenly mixing the dried substrate with the composite agent to obtain an organic fertilizer; the volume ratio of the leachate b to the leachate in step (1) is 1:10, and the volume ratio of the leachate b to water is 1:30; the composite agent is obtained by mixing red mud, Bacillus subtilis and quicklime, wherein the mass ratio of red mud, Bacillus subtilis and quicklime is 2:1:2, and the mass ratio of the composite agent to the dried substrate prepared in step (4) is 1:40.

[0024] Example 2

[0025] An organic fertilizer suitable for newly cultivated terraced fields, the organic fertilizer is prepared by the following preparation method: comprising the steps of: (1) A certain amount of copper-nickel sulfide ore smelting slag is mixed with concentrated sulfuric acid, and after the metal components in the copper-nickel sulfide ore smelting slag are leached out, a leaching solution and leaching slag are obtained, the leaching slag is dried, and the dried leaching slag is mixed with a certain amount of polyacrylic acid and potassium chloride particles passed through a 200-mesh sieve, pressed into shape, and solidified. The obtained block is calcined in an argon atmosphere at a calcination temperature of 600° C., and washed to obtain a micron / nanoporous structure carrier; (2) taking a certain amount of leachate a and mixing it with water to obtain a metal solution A, using the metal solution A to impregnate the micron / nanoporous structure carrier prepared in step (1), drying, and calcining the dried carrier under an inert atmosphere; the volume ratio of the leachate a to the leachate in step (1) is 1:20, and the volume ratio of the leachate a to water is 1:30; (3) The product prepared in step (2) is mixed evenly with the composite bacterial liquid, and the obtained mixture is then fully mixed with a certain amount of animal feces to obtain a fertilizer matrix; the composite bacterial liquid is obtained by mixing Azospirillum brasiliensis and Pantoea pineapple liquid, wherein the mass ratio of Azospirillum brasiliensis to Pantoea pineapple is 1:1, and the total mass of the bacterial species in the composite bacterial liquid is 15% of the mass of the product prepared in step (2). The mass ratio of the mixture to the animal feces is 1:25; (4) taking a certain amount of leachate b and mixing it with water to obtain a metal solution B, using the metal solution B to impregnate the fertilizer substrate prepared in step (3), drying, and evenly mixing the dried substrate with the composite agent to obtain an organic fertilizer; the volume ratio of the leachate b to the leachate in step (1) is 1:20, and the volume ratio of the leachate b to water is 1:30; the composite agent is obtained by mixing red mud, Bacillus subtilis and quicklime, wherein the mass ratio of red mud, Bacillus subtilis and quicklime is 2:1:2, and the mass ratio of the composite agent to the dried substrate prepared in step (4) is 1:40.

[0026] Example 3

[0027] An organic fertilizer suitable for newly cultivated terraced fields, the organic fertilizer is prepared by the following preparation method: comprising the steps of: (1) A certain amount of copper-nickel sulfide ore smelting slag is mixed with concentrated sulfuric acid, and after the metal components in the copper-nickel sulfide ore smelting slag are leached out, a leaching solution and leaching slag are obtained, the leaching slag is dried, and the dried leaching slag is mixed with a certain amount of polyacrylic acid and potassium chloride particles passed through a 200-mesh sieve, pressed into shape, and solidified. The obtained block is calcined in an argon atmosphere at a calcination temperature of 600° C., and washed to obtain a micron / nanoporous structure carrier; (2) taking a certain amount of leachate a and mixing it with water to obtain a metal solution A, using the metal solution A to impregnate the micron / nanoporous structure carrier prepared in step (1), drying, and calcining the dried carrier under an inert atmosphere; the volume ratio of the leachate a to the leachate in step (1) is 1:5, and the volume ratio of the leachate a to water is 1:30; (3) The product prepared in step (2) is mixed evenly with the composite bacterial liquid, and the obtained mixture is then fully mixed with a certain amount of animal feces to obtain a fertilizer matrix; the composite bacterial liquid is obtained by mixing Azospirillum brasiliensis and Pantoea pineapple liquid, wherein the mass ratio of Azospirillum brasiliensis to Pantoea pineapple is 1:1, and the total mass of the bacterial species in the composite bacterial liquid is 15% of the mass of the product prepared in step (2). The mass ratio of the mixture to the animal feces is 1:25; (4) taking a certain amount of leachate b and mixing it with water to obtain a metal solution B, using the metal solution B to impregnate the fertilizer substrate prepared in step (3), drying, and evenly mixing the dried substrate with the composite agent to obtain an organic fertilizer; the volume ratio of the leachate b to the leachate in step (1) is 1:5, and the volume ratio of the leachate b to water is 1:30; the composite agent is obtained by mixing red mud, Bacillus subtilis and quicklime, wherein the mass ratio of red mud, Bacillus subtilis and quicklime is 2:1:2, and the mass ratio of the composite agent to the dried substrate prepared in step (4) is 1:40.

[0028] Comparative Example 1 An organic fertilizer is prepared by the following preparation method: comprising the steps of: (1) Mixing a certain amount of steel slag with concentrated sulfuric acid, and obtaining a leachate and leach slag after the metal components in the steel slag are leached out, drying the leach slag, and uniformly mixing the dried leach slag with a certain amount of polyacrylic acid and potassium chloride particles sieved through a 200-mesh sieve, pressing and forming, and solidifying. The obtained block is calcined in an argon atmosphere at a calcination temperature of 600° C., and washed to obtain a carrier; (2) taking a certain amount of leachate a and mixing it with water to obtain a metal solution A, using the metal solution A to impregnate the support prepared in step (1), drying, and calcining the dried support under an inert atmosphere; the volume ratio of the leachate a to the leachate in step (1) is 1:10, and the volume ratio of the leachate a to water is 1:30; (3) The product prepared in step (2) is mixed evenly with the composite bacterial liquid, and the obtained mixture is then fully mixed with a certain amount of animal feces to obtain a fertilizer matrix; the composite bacterial liquid is obtained by mixing Azospirillum brasiliensis and Pantoea pineapple liquid, wherein the mass ratio of Azospirillum brasiliensis to Pantoea pineapple is 1:1, and the total mass of the bacterial species in the composite bacterial liquid is 15% of the mass of the product prepared in step (2). The mass ratio of the mixture to the animal feces is 1:25; (4) taking a certain amount of leachate b and mixing it with water to obtain a metal solution B, using the metal solution B to impregnate the fertilizer substrate prepared in step (3), drying, and evenly mixing the dried substrate with the composite agent to obtain an organic fertilizer; the volume ratio of the leachate b to the leachate in step (1) is 1:10, and the volume ratio of the leachate b to water is 1:30; the composite agent is obtained by mixing red mud, Bacillus subtilis and quicklime, wherein the mass ratio of red mud, Bacillus subtilis and quicklime is 2:1:2, and the mass ratio of the composite agent to the dried substrate prepared in step (4) is 1:40.

[0029] Comparative Example 2 An organic fertilizer is prepared by the following preparation method: comprising the steps of: (1) mixing a certain amount of copper-nickel sulfide ore smelting slag with concentrated sulfuric acid, leaching the metal components in the copper-nickel sulfide ore smelting slag to obtain a leaching solution and leaching slag, drying the leaching slag, and uniformly mixing the dried leaching slag with a certain amount of polyacrylic acid, pressing and forming, and solidifying. The obtained block is calcined in an argon atmosphere at a calcination temperature of 600° C. to obtain a carrier; (2) taking a certain amount of leachate a and mixing it with water to obtain a metal solution A, using the metal solution A to impregnate the support prepared in step (1), drying, and calcining the dried support under an inert atmosphere; the volume ratio of the leachate a to the leachate in step (1) is 1:10, and the volume ratio of the leachate a to water is 1:30; (3) The product prepared in step (2) is mixed evenly with the composite bacterial liquid, and the obtained mixture is then fully mixed with a certain amount of animal feces to obtain a fertilizer matrix; the composite bacterial liquid is obtained by mixing Azospirillum brasiliensis and Pantoea pineapple liquid, wherein the mass ratio of Azospirillum brasiliensis to Pantoea pineapple is 1:1, and the total mass of the bacterial species in the composite bacterial liquid is 15% of the mass of the product prepared in step (2). The mass ratio of the mixture to the animal feces is 1:25; (4) taking a certain amount of leachate b and mixing it with water to obtain a metal solution B, using the metal solution B to impregnate the fertilizer substrate prepared in step (3), drying, and evenly mixing the dried substrate with the composite agent to obtain an organic fertilizer; the volume ratio of the leachate b to the leachate in step (1) is 1:10, and the volume ratio of the leachate b to water is 1:30; the composite agent is obtained by mixing red mud, Bacillus subtilis and quicklime, wherein the mass ratio of red mud, Bacillus subtilis and quicklime is 2:1:2, and the mass ratio of the composite agent to the dried substrate prepared in step (4) is 1:40.

[0030] Comparative Example 3 An organic fertilizer is prepared by the following preparation method: comprising the steps of: (1) A certain amount of copper-nickel sulfide ore smelting slag is mixed with concentrated sulfuric acid, and after the metal components in the copper-nickel sulfide ore smelting slag are leached out, a leaching solution and leaching slag are obtained, the leaching slag is dried, and the dried leaching slag is mixed with a certain amount of polyacrylic acid and potassium chloride particles passed through a 200-mesh sieve, pressed into shape, and solidified. The obtained block is calcined in an argon atmosphere at a calcination temperature of 600° C., and washed to obtain a micron / nanoporous structure carrier; (2) taking a certain amount of leachate a and mixing it with water to obtain a metal solution A, using the metal solution A to impregnate the micron / nanoporous structure carrier prepared in step (1), drying, and calcining the dried carrier under an inert atmosphere; the volume ratio of the leachate a to the leachate in step (1) is 1:10, and the volume ratio of the leachate a to water is 1:30; (3) The product prepared in step (2) is mixed evenly with the composite bacterial solution, and the obtained mixture is then fully mixed with a certain amount of animal feces to obtain a fertilizer matrix; the composite bacterial solution is obtained by mixing Azospirillum brasiliensis and Frankia spp., wherein the mass ratio of Azospirillum brasiliensis to Frankia spp. is 1:1, and the total mass of the bacterial species in the composite bacterial solution is 15% of the mass of the product prepared in step (2). The mass ratio of the mixture to animal feces is 1:25; (4) taking a certain amount of leachate b and mixing it with water to obtain a metal solution B, using the metal solution B to impregnate the fertilizer substrate prepared in step (3), drying, and evenly mixing the dried substrate with the composite agent to obtain an organic fertilizer; the volume ratio of the leachate b to the leachate in step (1) is 1:10, and the volume ratio of the leachate b to water is 1:30; the composite agent is obtained by mixing red mud, Bacillus subtilis and quicklime, wherein the mass ratio of red mud, Bacillus subtilis and quicklime is 2:1:2, and the mass ratio of the composite agent to the dried substrate prepared in step (4) is 1:40.

[0031] Test example: This test example performs the following tests on the organic fertilizers prepared in Examples 1-3 and Comparative Examples 1-3: Overview of the Experimental Area The test site is located in Pengyang County, Guyuan City, Ningxia Hui Autonomous Region, in the northeast of Ningnan Mountain Area, with geographical coordinates of 106°69' east longitude and 35°93' north latitude. The region has a mid-temperate semi-humid semi-arid continental monsoon climate, with an annual precipitation of 400-500 mm, uncoordinated water and heat conditions, and precipitation is mainly concentrated in June-September. The average temperature is 7.9℃, the accumulated temperature ≥10℃ is 2500-2800℃, the sunshine hours are 2311.2 hours, and the frost-free period is 140-170 days. The test site is a newly reclaimed terraced field converted from a slope to a terrace, and the soil is loess soil. Before the test, the organic matter of the tillage layer soil was 6.89g / kg, and the available phosphorus was 1.22mg·kg -1 , ammonium nitrogen 1.90 mg kg -1 , nitrate nitrogen 12.94 mg kg -1 .

[0032] Experimental design The experiment set up 7 treatments, each with 3 replicates, and each plot had an area of ​​30 m 2 (5m×6m), with a 0.5m interval between each plot. Corn is cultivated using mulch film covering technology, with equal row spacing, 100 cm row spacing, and 20 cm plant spacing. There are 6 single rows of corn in each plot, 25 plants in each row, and 150 plants in each plot. The blank control group was taken as the control group without fertilization, and the other groups applied the organic fertilizers obtained in the above embodiments 1-3 and comparative examples 1-3. The organic fertilizers obtained in the above embodiments 1-3 and comparative examples 1-3 were applied according to the local conventional fertilizer application rate. Corn is sown at the end of April 2023 and harvested in early October. Corn growth depends on natural precipitation, and other matters are carried out according to the local farming schedule.

[0033] Sample collection and analysis Soil sample collection: At the trumpet stage on August 1, 2023 and the harvest stage on October 2, 2023, sampling points were randomly selected in each plot, and the surface soil (0-20 cm) was taken. Three replicates of each treatment were mixed evenly, and the samples were plastic-sealed and brought back to the laboratory. Some fresh soil samples were stored at 4°C, and some soil samples were naturally air-dried in a ventilated place. Plant residues were removed from the samples, and the samples were passed through soil sieves with diameters of 2 mm and 0.149 mm for the determination of soil physical and chemical properties.

[0034] Plant sample collection: After the corn matures, each plot will be harvested separately to determine the yield. A 2×2m sample plot that is not disturbed by human beings will be selected in each treatment plot for harvesting. The plants in the sample plot will be collected, air-dried and threshed.

[0035] The moisture content was measured by drying method, the total nitrogen in soil was determined by Kjeldahl method, the ammonium nitrogen and nitrate nitrogen in soil were determined by colorimetry, and the activities of soil extracellular enzymes including β-glucosidase (BG) and alkaline phosphatase (ALP) were determined by CH3COONa·3H2O buffer-96 microwell ELISA plate fluorescence method. All sample indicators were measured three times, and the mean and standard deviation were calculated using Excel 2021.

[0036] (1) Soil nutrient content and yield under different treatments The application of the organic fertilizers described in Examples 1-3 and Comparative Examples 1-3 has different effects on improving the moisture content and nutrient content of the added soil.

[0037] In the large bell mouth stage, compared with no fertilization, the soil moisture content under the treatment of Example 1 increased most significantly, by 25%, the soil moisture content under the treatment of Example 3 increased by 23%, the soil moisture content under the treatment of Example 2 increased by 20%, and the soil moisture content after the treatment of Comparative Examples 1-3 increased by 18%, 17%, and 19%, respectively. In terms of nutrient content, the organic fertilizer treatment described in Examples 1-3 significantly increased the TN content of the soil, by 34%, 29%, and 33%, respectively, and the treatment of Comparative Examples 1-3 increased by 25%, 20%, and 26%. For ammonium nitrogen content, the improvement effect of Example 1 was the most significant, increasing by 30%, and the treatments of Examples 2-3 also increased by 23% and 27%, respectively. The improvement effect of Comparative Examples 1-3 was limited, increasing by 15%, 12%, and 14%, respectively. In terms of nitrate nitrogen content, the treatment of Example 1 increased by 32 mg·kg -1 , Example 2-3 treatments increased by 25 mg·kg -1 , 29mg·kg -1 The nitrate nitrogen content of the comparative examples 1-3 was limited, and only increased by 15 mg·kg -1 , 9mg·kg -1 , 13mg·kg -1 .

[0038] At the harvest period, compared with no fertilization, the addition of organic fertilizers described in Examples 1-3 and Comparative Examples 1-3 had an impact on soil moisture content. In terms of soil nutrients, the TN content of each treated soil showed different degrees of improvement. The treatment in Example 1 had the highest increase, reaching 59%, the treatment in Example 2 increased by 55%, and the treatment in Example 3 increased by 52%. The increases in the treatments in Comparative Examples 1-3 were smaller, at 38%, 26%, and 40%, respectively. The ammonium nitrogen content increased significantly by 6%, 5%, and 5% under the treatments in Examples 1-3, and there were no significant changes in the other treatments. The nitrate nitrogen content showed different degrees of increase, among which the treatment in Example 1 increased the most, reaching 33 mg·kg -1 , Example 2-3 treatments increased by 22 mg·kg -1 , 26mg·kg -1 , the treatments of comparative examples 1-3 increased by 12 mg·kg -1 , 9mg·kg -1 and 11 mg kg -1 .

[0039] After the addition of organic fertilizer, the yield of each treatment was increased. Compared with no fertilization, the yield of Example 1 increased by 128%, the yield of Example 2 increased by 109%, the yield of Example 3 increased by 121%, the yield of Comparative Example 1 increased by 88%, the yield of Comparative Example 2 increased by 72%, and the yield of Comparative Example 3 increased by 81%.

[0040] (2) Soil enzyme activities under different treatments At the big bell mouth stage, compared with no fertilization, the BG enzyme activity in Example 1 treatment increased most significantly, with an increase of 93%, followed by Examples 2-3 treatments, which increased by 81% and 85%, respectively. The BG enzyme activity in Comparative Example 1 treatment increased by 55%, while the increase in Comparative Example 2 treatment was the smallest, only 38%, and the BG enzyme activity in Comparative Example 3 treatment increased by 46%. Similarly, the NAG enzyme activity in Example 1 treatment increased most significantly, with an increase of 4 times, followed by Examples 2 and 3 treatments, with increases of 2.6 times and 3 times, respectively. Comparative Examples 1-3 treatments increased by 89%, 43% and 77%, respectively. In terms of ALP enzyme activity, the increase in Example 1 treatment was the highest, reaching 58%, while Examples 2 and 3 treatments increased by 52% and 56%, respectively. The ALP enzyme activity in Comparative Example 1 treatment increased by 25%, the ALP enzyme activity in Comparative Example 3 treatment increased by 22%, and there was no significant change in the ALP enzyme activity in Comparative Example 2 treatment.

[0041] At the harvest stage, compared with no fertilization, the BG enzyme activity of each treatment increased to varying degrees, with the largest increase in Example 1, reaching 110%, followed by Example 2, which increased by 77%, and Example 3, which increased by 97%; the comparative examples 1-3 increased by 55%, 36%, and 52%, respectively. The ALP enzyme activity also increased to varying degrees, with the enzyme activities of Examples 1-3 increasing by 22%, 13%, and 17%, respectively, and the enzyme activities of Comparative Examples 1-3 increasing by 14%, 9%, and 15%, respectively. In terms of NAG enzyme activity, the improvement effect of Example 1 was the most significant, reaching 452%, followed by Examples 2-3, which increased by 375% and 382%, respectively, and the comparative examples 1-3 also increased by 102%, 81%, and 119%, respectively.

[0042] After adding the organic fertilizers described in Examples 1-3 and Comparative Examples 1-3, the soil moisture content of the soil treated by Examples 1-3 at the large bell mouth stage was significantly increased compared with no fertilizer application, indicating that the organic fertilizers described in Examples 1-3 suitable for newly cultivated terraced fields have a significant effect in improving soil moisture content.

[0043] In the present invention, the soil BG enzyme activity and ALP enzyme activity are significantly improved after adding organic fertilizer. This is because after the addition of exogenous organic fertilizer, the organic fertilizer is degraded, providing a large amount of energy for microorganisms in the soil, optimizing the living environment of the soil, and promoting the activity of organic carbon decomposition enzymes while releasing nutrients. Fertilization can improve the ALP of soil with low organic matter content. The addition of organic fertilizer promotes the metabolism of the root system, increases the organic matter content and thus increases the enzyme activity, which is the reason why the ALP enzyme activity is significantly improved.

[0044] The application of organic fertilizer can increase corn yield. In the present invention, the corn yield of each treatment is improved after adding organic fertilizer. After the addition of organic fertilizer, it provides rich organic matter and nutrients to the soil, promotes the improvement of soil properties and the supply of nutrients, and provides a good environment for crop growth, thereby achieving increased yield.

[0045] After adding different organic fertilizers, the soil nutrient status was significantly improved. Each treatment significantly increased the soil total nitrogen, nitrate nitrogen and microbial biomass nitrogen content. The activities of β-1,4-glucosidase and N-acetyl-β-D-glucosidase in each treatment soil were significantly improved. The addition of different organic fertilizers promoted the increase in corn yield, especially the application of Example 1, which had the most significant effect on rapidly improving soil nutrients in a short period of time, effectively promoting crop yield.

[0046] The present invention does not need to introduce new metal components in the process of preparing organic fertilizers, fully utilizes various components in the copper-nickel sulfide ore smelting slag, recovers metal elements in the copper-nickel sulfide ore smelting slag, and makes the metal-loaded organic fertilizer become a slow-release source of trace nutrients for loaded bacteria and crops. Compared with other wastes such as slag, the specific metal composition and other factors in the copper-nickel sulfide ore smelting slag enhance the activity of the loaded bacterial flora. The present invention improves the utilization rate of the copper-nickel sulfide ore smelting slag and realizes the solid waste resourceization of the smelting slag.

[0047] The micron / nano pore structure carrier prepared by the present invention enables the metal load layer to play a micronutrient slow-release function, and potassium chloride is selected as a pore-forming agent, which reduces the secondary pollution of the soil caused by the introduction of chemical reagents in the preparation process of organic fertilizers, and the residual potassium chloride can still be used as a micronutrient slow-release source. At the same time, the biological nitrogen fixation and other effects of the flora in the organic fertilizer and the physical adsorption of the micron / nano pore structure carrier form a synergistic effect. The composite structure prepared by the present invention is more suitable as a host of microorganisms, and the biological compatibility of the carrier is improved.

[0048] The present invention finds that by introducing organic fertilizers simultaneously with Azospirillum brasiliensis, Pantoea ananas and Bacillus subtilis, in addition to providing energy substances to each other between the strains, in an organic fertilizer system composed of a specific structural carrier and a specific metal, the bacterial community recorded in the present invention can make the organic fertilizer have better fertility and higher nitrogen fixation efficiency than the organic fertilizer obtained by other strain combinations. The organic fertilizer of the present invention acts on the soil, can increase the soil nutrient content and crop yield, and can increase the enzyme activity in the soil.

[0049] The present invention prepares soil organic fertilizer containing a porous matrix, and the silicate matrix in the smelting slag is efficiently converted through high-temperature phase change reconstruction, while metal elements such as Cu and Ni are effectively recovered. The prepared porous matrix has both a carrier skeleton and a slow-release function, which can replace traditional carrier materials, thereby realizing high-value-added resource utilization of waste.

[0050] The organic fertilizer in the present invention can increase the organic matter and nitrogen content of the soil, and the composite bacterial liquid can promote the decomposition of organic matter and the effectiveness of nutrients, promote soil improvement, and thus be beneficial to the improvement of soil productivity; at the same time, the organic fertilizer can significantly increase the soil nutrient content and soil enzyme activity, promote the improvement of soil fertility, and ultimately achieve the effect of soil conditioning.

[0051] The applicant declares that the present invention illustrates the technical solution of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent measures for the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0052] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

[0053] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for preparing organic fertilizer suitable for newly reclaimed terraced fields, characterized in that: The steps include: (1) mixing a certain amount of copper-nickel sulfide ore smelting slag with concentrated sulfuric acid, leaching the metal components in the copper-nickel sulfide ore smelting slag to obtain a leaching solution and leaching slag, drying the leaching slag, and uniformly mixing the dried leaching slag with a certain amount of polyacrylic acid and potassium chloride particles, pressing and forming, and solidifying. The obtained block is calcined in an inert atmosphere, washed, and a micron / nanoporous structure carrier is obtained; (2) taking a certain amount of leachate a and mixing it with water to obtain a metal solution A, using the metal solution A to impregnate the micron / nanoporous structure carrier prepared in step (1), drying, and calcining the dried carrier under an inert atmosphere; (3) uniformly mixing the product prepared in step (2) with the composite bacterial solution, and then fully mixing the obtained mixture with a certain amount of animal feces to obtain a fertilizer matrix; (4) taking a certain amount of leachate b and mixing it with water to obtain a metal solution B, using the metal solution B to impregnate the fertilizer matrix prepared in step (3), drying it, and evenly mixing the dried matrix with the composite agent to obtain an organic fertilizer; The composite bacterial solution in step (3) is obtained by mixing Azospirillum brasiliensis and Pantoea ananas, wherein the mass ratio of Azospirillum brasiliensis to Pantoea ananas is 1:(1-2), and the total mass of the bacterial species in the composite bacterial solution is 3-20% of the mass of the product prepared in step (2); The composite agent in step (4) is obtained by mixing red mud, Bacillus subtilis and quicklime, wherein the mass ratio of red mud, Bacillus subtilis and quicklime is (2-5): (1-3): (2-5), and the mass ratio of the composite agent to the dried matrix prepared in step (4) is 1: (10-100).

2. The preparation method according to claim 1, characterized in that: In step (1), the calcination temperature is 500-800° C., the inert atmosphere is one of nitrogen and argon, and the potassium chloride particles are obtained by passing through a 200-mesh sieve.

3. The preparation method according to claim 1, characterized in that: In step (2), the volume ratio of the leachate a to the leachate in step (1) is 1:(5-20), and the volume ratio of the leachate a to water is 1:(10-50).

4. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of the mixture to the animal feces is 1:(5-30).

5. The preparation method according to claim 1, characterized in that: In step (4), the volume ratio of the leachate b to the leachate in step (1) is 1:(5-20), and the volume ratio of the leachate b to water is 1:(10-50).

6. An organic fertilizer suitable for newly reclaimed terraced fields, characterized in that: The organic fertilizer is prepared by the preparation method according to any one of claims 1 to 5.

7. A soil fertilization method, characterized in that: The fertilization method adopts the organic fertilizer described in claim 6.