Preparation method of multi-source mineral solid waste compounded agricultural and pastoral decomposed substance soilless rice seedling raising substrate

Abstract

The invention discloses a preparation method of a multi-source mineral solid waste compounded agricultural and pastoral decomposed substance soilless rice seedling raising substrate, and belongs to the technical field of agricultural waste resource utilization and modern agricultural cultivation. According to the method, agricultural and pastoral decomposed substances and multi-source mineral solid wastes are used as main raw materials, and a novel seedling raising substrate system with an organic-inorganic synergistic effect is constructed through a two-stage regulation and control process of hydrothermal activation pretreatment and precise volume compounding; according to the process, the surface of the mineral solid waste is directionally acidified and modified through a hydrothermal reaction, the pH value is remarkably reduced to a suitable range of 5.5-6.5, meanwhile, interface coupling of the mineral solid waste and agricultural and pastoral decomposed substances is promoted, a stable organic-inorganic composite structure is formed, and the mineral solid waste has excellent pH buffering capacity and ion exchange capacity, is reasonable in pore structure and excellent in water holding performance, and can be used as a water-retaining agent for the agricultural and pastoral decomposed substances. Synergistic high-value utilization of industrial and agricultural wastes is achieved, a full-quantification, functional and standardized matrix substitution scheme is provided for mechanical seedling raising of rice in the cold region, and economic benefits and ecological benefits are achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of agricultural waste resource utilization and modern agricultural cultivation technology, and particularly relates to a preparation method of a multi-source mineral solid waste compounded agricultural and livestock manure humus soilless rice seedling raising substrate. BACKGROUND

[0002] "Seedlings are half-ripe rice, and seedlings are strong and high-yield", seedlings are the primary link of rice mechanized production and the basis of rice harvest. With the large-scale promotion of rice mechanical transplanting in China, the limitations of traditional nutrient soil seedling raising are increasingly prominent. In order to solve the problems of traditional seedling raising, such as difficulty in taking soil, damage to vegetation, and ease the plight of the shortage of rural labor, the research and application of soilless rice seedling raising substrate are paid more and more attention. Straw humus, as an important alternative material for soilless seedling raising, is in line with the development concept of green agriculture and resource recycling. However, there are still some deficiencies when it is used alone: the pH value is too high, the straw humus is usually alkaline, and additional acid needs to be added to meet the growth needs of rice seedlings; water control is difficult, straw humus has poor water retention, which easily leads to drought or waterlogging of seedlings; the structure is not stable enough, and it is easy to scatter seedlings during mechanical transplanting, affecting the transplanting efficiency and survival rate. Therefore, in actual agricultural production and application, straw humus is often used as the core raw material to prepare humus substrate through "compounding" process to solve its inherent defects.

[0003] Heilongjiang Province is an important mineral resource base in China, and produces a large amount of mineral solid waste resources every year. These mineral solid wastes mainly come from tailings sand brought by graphite mining, coal gangue and coal slime produced by coal mining and washing, and fly ash produced by coal-fired power plants, etc. Long-term storage of these mineral solid wastes not only occupies a large amount of land, but also easily produces dust under dry and windy weather, and the leachate containing heavy metal components also leaks with rainwater, causing soil and groundwater pollution, and posing serious environmental and safety risks. In view of this situation, the development of rice seedling raising substrate by compounding various types of mineral solid waste after harmless treatment and straw humus not only effectively solves the problems of traditional seedling raising, such as difficulty in taking soil and damage to farmland, but also realizes the collaborative resource utilization of industrial waste. SUMMARY

[0004] In order to solve the above technical problems, the application provides a preparation method of a multi-source mineral solid waste compounded agricultural and livestock manure humus soilless rice seedling raising substrate.

[0005] The application is based on a hydrothermal activation pretreatment technology, which controls the surface physicochemical properties of multi-source mineral solid waste (graphite tailings after beneficiation, waste rock or dump, etc.) by directional acidification modification treatment, and enhances the interface bonding capacity with agricultural and pastoral compost substrates. The inorganic framework support of acidified mineral solid waste and the organic functional characteristics of agricultural and pastoral compost substrates are utilized to construct a new type of rice seedling raising substrate system with "inorganic-organic" synergistic effect, to adjust the pH buffer performance and ion exchange capacity of the substrate, and to form a rice seedling raising substrate product with reasonable pore structure and excellent water holding performance.

[0006] A preparation method of a multi-source mineral solid waste compounded agricultural and pastoral compost soilless rice seedling raising substrate, specifically completed by the following steps:

[0007] I. The multi-source mineral solid waste and the crushed biomass are added to water, mixed uniformly, then transferred to a reaction kettle, and then a catalyst is added for reaction. After the reaction is completed, the product after reaction is subjected to solid-liquid separation, and the solid product is collected to obtain a multi-source mineral solid waste substrate;

[0008] II. The multi-source mineral solid waste substrate and the agricultural and pastoral compost substrate are compounded according to different volume ratios, and then a certain amount of rice seedling raising and seedling strengthening agent is added to obtain a soilless rice seedling raising substrate. Finally, rice seedling raising is carried out according to the rice mechanical transplanted rice seedling raising process.

[0009] The beneficial effects of the application are as follows:

[0010] 1. The application uses agricultural and pastoral compost and multi-source mineral solid waste as main raw materials, which have wide sources and low cost, and has significant economic and ecological benefits;

[0011] 2. The application realizes directional regulation of the surface properties of mineral solid waste through hydrothermal activation pretreatment technology, promotes the organic-inorganic interface coupling of the mineral solid waste and the agricultural and pastoral compost substrate, and realizes precise regulation of the physical structure and chemical function of the substrate;

[0012] 3. The seedling raising substrate product prepared by the application has the functions of nutrient slow release, pH buffering and biological growth promotion, and through compounding optimization of the pore structure and water holding performance of the substrate, it provides a full-quantitative, functional and standardized substrate replacement scheme for mechanical rice seedling raising in cold regions. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 Fig. 3 is a graph of seedling height and biomass of rice seedlings of different proportioning rice seedling raising substrates of Example 3 sowed for 10 days;

[0014] Figure 2 Fig. 4 is a graph of seedling height and biomass of rice seedlings of different proportioning rice seedling raising substrates of Example 3 sowed for 18 days. DETAILED DESCRIPTION

[0015] Specific embodiment one: the preparation method of the multi-source mineral solid waste compound agricultural and livestock compost soilless rice seedling raising substrate, specifically is completed according to the following steps:

[0016] I. The multi-source mineral solid waste and the crushed biomass are added to water, uniformly mixed, then transferred to a reaction kettle, and then a catalyst is added for reaction. After the reaction is completed, the product after the reaction is subjected to solid-liquid separation, and the solid product is collected to obtain a multi-source mineral solid waste substrate;

[0017] II. The multi-source mineral solid waste substrate and the agricultural and livestock compost substrate are compounded according to different volume ratios, and then a certain amount of rice seedling raising agent is added to obtain a soilless rice seedling raising substrate. Finally, the rice seedling raising process is carried out according to the rice mechanical transplanted rice seedling raising process.

[0018] This embodiment takes the agricultural and livestock compost substrate and the multi-source mineral solid waste substrate as the main raw materials, and constructs a new seedling raising substrate system with "organic-inorganic" synergistic effect through the two-stage regulation process of hydrothermal activation pretreatment and precise volume compounding. The process modifies the surface of the mineral solid waste through hydrothermal reaction, significantly reduces the pH value to the appropriate range of 5.5-6.5, and promotes the interface coupling of the mineral solid waste and the agricultural and livestock compost, forming a stable organic-inorganic composite structure. The obtained functional substrate has multiple performance advantages: first, it has excellent pH buffering capacity and ion exchange capacity; second, it realizes the slow release of nutrients through organic-inorganic compounding; third, the pore structure is reasonable, and the water holding performance is excellent. Experiments show that the biomass and height of the seedlings cultivated by the mineral solid waste substrate compounded with the agricultural and livestock compost substrate are significantly improved, and the root development is significantly improved. The present application realizes the synergistic high-value utilization of industrial and agricultural wastes, provides a full-quantitative, functional and standardized substrate replacement scheme for rice mechanized seedling raising in cold regions, and has economic and ecological benefits.

[0019] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the multi-source mineral solid waste in step one is a mixture of one or more of graphite tailings, waste rock or waste soil after beneficiation. The other steps are the same as those in specific embodiment one.

[0020] Specific embodiment three: the difference between this embodiment and one of specific embodiments one or two is that the biomass is one or more of straw, trees, agricultural product processing waste, agricultural and forestry waste and poultry manure generated in the process of agricultural and forestry production. The other steps are the same as those in specific embodiments one or two.

[0021] Specific embodiment four: the difference between this embodiment and one of the specific embodiments one to three is that the catalyst in step one is a mixture of one or more of ferric sulfate, ferric chloride, calcium chloride, magnesium chloride, ferric nitrate, calcium hydroxide, sodium hydroxide and potassium hydroxide. The other steps are the same as specific embodiments one to three.

[0022] Specific embodiment five: the difference between this embodiment and one of the specific embodiments one to four is that the mass ratio of the pulverized biomass, multi-source mineral solid waste and catalyst in step one is 1:(0.1-5):(0.01-2). The other steps are the same as specific embodiments one to four.

[0023] Specific embodiment six: the difference between this embodiment and one of the specific embodiments one to five is that the total mass of the pulverized biomass, multi-source mineral solid waste and catalyst in step one and the volume of water is 1g:(1mL-20mL). The other steps are the same as specific embodiments one to five.

[0024] Specific embodiment seven: the difference between this embodiment and one of the specific embodiments one to six is that the device for hydrothermal reaction in step one is a temperature-resistant, pressure-resistant and corrosion-resistant closed reactor with a corrosion-resistant lining inside. The other steps are the same as specific embodiments one to six.

[0025] Specific embodiment eight: the difference between this embodiment and one of the specific embodiments one to seven is that the reaction temperature in step one is 120℃-250℃, and the hydrothermal reaction time is 1h-48h. The other steps are the same as specific embodiments one to seven.

[0026] Specific embodiment nine: the difference between this embodiment and one of the specific embodiments one to eight is that the volume ratio of multi-source mineral solid waste substrate to farm and livestock compost substrate in step two is 1:(0.1-5); the farm and livestock compost in step two is purchased from Heilongjiang Beidahuang Agricultural Co., Ltd. Qinglongshan Branch, which is made of rice straw fermented by low-temperature resistant bacterial agent. The other steps are the same as specific embodiments one to eight.

[0027] Specific embodiment ten: the difference between this embodiment and one of the specific embodiments one to nine is that the volume ratio of the quality of the rice seedling strengthening agent to the multi-source mineral solid waste substrate in step two is (5g-10g):1L. The other steps are the same as specific embodiments one to nine.

[0028] The following examples are used to verify the beneficial effects of the present application:

[0029] Example 1: the preparation method of acidified graphite tailings, which is completed according to the following steps:

[0030] I. Take 6 portions of 10 g of crushed corn stalks, and then take 0 g, 1 g, 5 g, 10 g, 20 g, and 40 g of graphite tailings sand, respectively. Add 6 portions of 10 g of crushed corn stalks and 0 g, 1 g, 5 g, 10 g, 20 g, and 40 g of graphite tailings sand, respectively, to 6 portions of 100 mL of water, mix well, and then transfer to 6 200 mL reaction kettles, respectively. Add 0.41 g of ferric chloride (analytical pure) to each of the 6 reaction kettles, respectively, and then conduct hydrothermal reaction at 200°C for 1 h, 2 h, 4 h, and 6 h, respectively. After the reaction is completed and the reaction kettle is cooled to room temperature, open the reaction kettle, separate by suction filtration, collect the solid product, and obtain the acidified graphite tailings sand.

[0031] The biomass hydrothermal reaction can generate a large amount of small molecule organic acid, which can effectively reduce the pH value of the graphite tailings sand. According to the data in Tables 1-4, the pH value of the hydrothermal reaction of the straw alone decreases with the extension of the reaction time, which may be due to the fact that with the extension of the reaction time, more and more small molecule acids are generated by the hydrolysis of cellulose / hemicellulose in the straw at high temperature. With the increase of the mass of the graphite tailings sand, the pH value of the solid product gradually increases, and 40 g of tailings sand causes the pH value to jump to 5.56-6.26 (much lower than the original tailings sand pH = 8.48). When the straw: tailings sand = 1:1-2 (w / w), the pH value is maintained at 2.78-4.07 (6 h), the organic matter retention rate is 18.56-21.57%, which meets the buffer space requirement for subsequent pH adjustment for seedling raising. The pH value of the graphite tailings sand is reduced from alkaline (8.48) to weakly acidic (2.78-5.56 adjustable) through hydrothermal pretreatment, avoiding secondary pollution caused by traditional acid treatment (such as HCl).

[0032] Tables 1-4 show the effects of different reaction times and different corn straw-graphite tailings mass ratios on the pH, electrical conductivity (EC), and organic matter content of the solid product

[0033] Table 1

[0034]

[0035] Table 2

[0036]

[0037] Table 3

[0038]

[0039] Table 4

[0040]

[0041] Example 2: The acidified graphite tailings sand obtained by hydrothermal reaction of straw: tailings sand = 1:4 (w / w) for 6 h in Example 1 was mixed with straw humus (purchased from Heilongjiang Beidahe Agricultural Co., Ltd. Qingshan Branch, which is made of rice straw fermented by low-temperature resistant bacterial agent) to prepare a rice seedling raising substrate. The straw humus and the acidified graphite tailings sand were mixed at a volume ratio of 10:2, 10:6, and 10:10 to prepare a rice seedling raising substrate. The physicochemical properties of the rice seedling raising substrate were determined.

[0042] According to the data in Table 5, as the proportion of tailings sand increased, the pH decreased significantly from 8.56 (10:2) to 6.09 (10:10), and the 10:10 ratio reached the optimal pH range (5.5-6.5) for rice seedling raising. The EC value decreased from 1.87 mS / cm (10:2) to 1.03 mS / cm (10:10), and the EC value of all ratios was below the safety threshold of 2 mS / cm. The organic matter content decreased from 28.53% to 14.44%. The bulk density increased from 0.59 g / cm 3 to 0.88 g / cm 3 , and the porosity decreased from 45.65% to 33.94%. This example demonstrates that the two-stage regulation of acidification pretreatment and precise volume mixing can prepare functional seedling raising substrates suitable for different agricultural needs.

[0043] Table 5: Physicochemical properties of seedling raising substrates with different straw humus and graphite tailings sand volume ratios

[0044]

[0045] Example 3: The acidified graphite tailings sand obtained by hydrothermal reaction of straw: tailings sand = 1:4 (w / w) for 6 h in Example 1 was mixed with straw humus (purchased from Heilongjiang Beidahe Agricultural Co., Ltd. Qingshan Branch, which is made of rice straw fermented by low-temperature resistant bacterial agent) to prepare a rice seedling raising substrate. The straw humus and the acidified graphite tailings sand were mixed at a volume ratio of 10:6 (1.2 L straw humus + 0.8 L acidified graphite tailings sand) and 10:10 (1.0 L straw humus + 1.0 L acidified graphite tailings sand) to prepare a rice seedling raising substrate. A 100% conventional nursery soil was used as a control. The different proportions of seedling raising substrate and conventional nursery soil were uniformly spread on the standard blanket seedling tray with a thickness of 2.0 cm. Rice seedling raising agent (Miaofu brand, produced by Jingxian City Jingxing Chemical Co., Ltd.) was added to each tray at a dosage of 15 g. The rice seedling was sown at a rate of 120 g, and the rice variety was Longjing 31. The rice seedling was raised according to the requirements of rice machine transplanting. The seedling quality was compared by analyzing the plant height and biomass of the rice seedlings at the 10th and 18th days after sowing.

[0046] Rice seedling growth indicators such as Figure 1 and Figure 2 As shown in the figure, according to the seedling growth monitoring data, with the increase of the proportion of acid-treated graphite tailings sand, the seedling growth indicators showed a significant increase: the dry weight of the 10:10 ratio group reached 0.86g at 18 days after sowing, which was 14.7% higher than the control (0.75g); the plant height increased to 10.16cm, which was 19.7% higher than the control (8.49cm); the root length increased from 2.22cm to 3.58cm, an increase of 61%; and the dry weight growth rate of the 10:10 ratio group was 26.7% higher than the control during the 10-18 day period. This example demonstrates that by precisely compounding (10:10) the decomposed material and the acid-treated graphite tailings sand, a functional seedling raising substrate with a significant growth-promoting effect can be prepared, and its biomass accumulation and plant height growth are better than traditional nutrient soil seedling raising, fully meeting the strict requirements of mechanized transplanted rice on seedling quality.

Claims

1. A method for preparing a soilless rice seedling substrate composed of multi-source mineral solid waste and agricultural and livestock compost, characterized in that... The preparation method is specifically carried out according to the following steps:

1. Add multi-source mineral solid waste and crushed biomass to water, mix evenly, transfer to a reaction vessel, add a catalyst to react, and after the reaction is completed, separate the reaction products into solid and liquid, collect the solid products, and obtain multi-source mineral solid waste matrix.

2. Mix the multi-source mineral solid waste substrate with the agricultural and livestock compost substrate in different volume ratios, and then add a certain amount of rice seedling strengthening agent to obtain the rice seedling substrate. Finally, carry out rice seedling cultivation according to the rice machine transplanting and seedling cultivation process.

2. The method for preparing a soilless rice seedling substrate by compounding multi-source mineral solid waste with agricultural and livestock compost as described in claim 1, characterized in that... The multi-source mineral solid waste mentioned in step one refers to one or a mixture of several of the following: graphite tailings, waste rock, or waste soil after mineral processing.

3. The method for preparing a soilless rice seedling substrate by compounding multi-source mineral solid waste with agricultural and livestock compost as described in claim 1, characterized in that... The biomass mentioned refers to one or more of the following: straw, trees, by-products from agricultural and forestry production, agricultural and forestry waste, and poultry and livestock manure generated during livestock production.

4. The method for preparing a soilless rice seedling substrate by compounding multi-source mineral solid waste with agricultural and livestock compost as described in claim 1, characterized in that... The catalyst mentioned in step one is one or a mixture of several of the following: ferric sulfate, ferric chloride, calcium chloride, magnesium chloride, ferric nitrate, calcium hydroxide, sodium hydroxide, and potassium hydroxide.

5. The method for preparing a soilless rice seedling substrate by compounding multi-source mineral solid waste with agricultural and livestock compost as described in claim 1, characterized in that... The mass ratio of the crushed biomass, multi-source mineral solid waste and catalyst mentioned in step one is 1:(0.1~5):(0.01~2).

6. The method for preparing a soilless rice seedling substrate by compounding multi-source mineral solid waste with agricultural and livestock compost as described in claim 1, characterized in that... The total mass of the crushed biomass, multi-source mineral solid waste and catalyst mentioned in step one, and the volume ratio of water, is 1g:(1mL~20mL).

7. The method for preparing a soilless rice seedling substrate by compounding multi-source mineral solid waste with agricultural and livestock compost as described in claim 1, characterized in that... The hydrothermal reaction apparatus described in step one is a closed reactor that is resistant to temperature, pressure, and corrosion, and has an internal anti-corrosion lining.

8. The method for preparing a soilless rice seedling substrate by compounding multi-source mineral solid waste with agricultural and livestock compost as described in claim 1, characterized in that... The reaction temperature in step one is 120℃~250℃, and the hydrothermal reaction time is 1h~48h.

9. The method for preparing a soilless rice seedling substrate composed of multi-source mineral solid waste and agricultural and livestock compost as described in claim 1, characterized in that... The volume ratio of the multi-source mineral solid waste matrix to the agricultural and livestock compost matrix mentioned in step two is 1:(0.1~5).

10. The method for preparing a soilless rice seedling substrate by compounding multi-source mineral solid waste with agricultural and livestock compost as described in claim 1, characterized in that... The mass ratio of the rice seedling raising and strengthening agent to the volume ratio of the multi-source mineral solid waste matrix in step two is (5g~10g):1L.

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