Method for preparing acidified soil conditioner from dolomite waste residues

Abstract

The invention relates to a method for preparing an acidified soil conditioner by using dolomite waste residues, which belongs to the technical field of soil conditioners, and specifically comprises the following steps: mixing activated dolomite, mineral source humic acid, a macromolecular adhesive and a fermented organic matter in a ratio of 1: 0.4: 0.001: 0.75; the acidified soil conditioner can be obtained by uniformly mixing the components, and the prepared acidified soil conditioner can remarkably improve the pH of acidified soil and increase soil nutrients so as to improve the crop yield, and can realize resource utilization of dolomite.

Description

Technical Field

[0001] The invention relates to a method for preparing an acidified soil conditioner by utilizing dolomite waste residue, and belongs to the technical field of soil conditioners. Background Art

[0002] There has been extensive research on the use of environmental materials in soil remediation, but most studies have been limited to the application of single materials or organic materials, with less research on the optimized application of organic-inorganic composite materials. In recent years, the use of inorganic-organic composite environmental materials such as minerals and humic acid in soil improvement has received more widespread attention. Research focuses on acidified soils in the south caused by acid rain and excessive use of nitrogen fertilizers, while the soils in greenhouses and orchards in the north are mainly due to excessive use of chemical nitrogen fertilizers and poor management, resulting in a decrease in soil pH, an increase in soil acidity, a large loss of medium-sized elements required by plants such as calcium, magnesium, and silicon, and the activation of heavy metals such as cadmium and lead, which seriously pollute the environment and threaten human health. There is an urgent need to develop composite multifunctional soil conditioners that can regulate soil acidity, improve soil structure and nutrient supply, and increase crop yield and quality.

[0003] Dolomite is rich in calcium, magnesium, and other secondary elements beneficial to plant growth. After calcination, its alkalinity increases, activating calcium and magnesium. Using dolomite for soil conditioning and acidification can both neutralize soil acidity and provide calcium and magnesium nutrients. Humic acid, the most active component of soil humus, contains various oxygen-containing active functional groups, such as carboxyl, hydroxyl, and carbonyl groups, which can effectively improve soil physical structure and provide complexation and slow-release fertilizer efficacy. Water-retaining agents absorb soil water through a network of hydrophilic groups, expanding into a hydrogel. This creates a water potential difference with the soil water, slowly releasing water to maintain moisture in the surrounding soil. In agricultural applications, this can prevent soil erosion and improve soil moisture conditions. Fermented organic matter is rich in organic matter, which helps increase soil organic matter content, improve soil fertility, improve soil physical and chemical properties, improve soil structure, and ultimately enhance the plant rhizosphere environment. Therefore, combining these four environmental materials can develop a multifunctional, low-cost soil conditioner. Summary of the Invention

[0004] In order to solve the technical problems existing in the prior art, the present invention provides a method for preparing an acidified soil conditioner using dolomite waste residue. The prepared acidified soil conditioner can significantly increase the pH of acidified soil, increase soil nutrients and thus increase crop yields, and can realize the resource utilization of dolomite.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is a method for preparing an acidified soil conditioner using dolomite waste residue, which is mainly composed of the following components. According to the mass percentage, the ratio of activated dolomite: mineral humic acid: polymer adhesive: fermented organic matter is: 1:0.4:0.001:0.75; the above components are evenly mixed to obtain the acidified soil conditioner.

[0006] Preferably, the preparation method of the activated dolomite is to calcine the dolomite ore at a high temperature of above 900°C for 1-2 hours to form a powder, with a pH of above 10.0, a CaO content of above 50%, a MgO content of above 30%, and a SiO2 content of 3%, and then crush it and pass it through a 60-mesh sieve to obtain the activated dolomite.

[0007] Preferably, the powdered solid is obtained by the weathered coal alkali method, has a purity greater than 70%, a pH greater than 8, an electrical conductivity greater than 2 ms / cm, and an organic matter content of more than 40%.

[0008] Preferably, the polymer adhesive is a polymer material with a linear structure and a molecular weight of 150,000 Da.

[0009] Preferably, the preparation method of the fermented organic matter is to mix crop straw and livestock and poultry manure in a ratio of 3:1, and then subject it to special fermentation, so that the degree of maturity reaches 80%, the organic matter content is more than 40%, and it is homogenized through a 20-mesh sieve.

[0010] Compared with the existing technology, the present invention has the following technical effects: the acidified soil conditioner prepared by the present invention can effectively increase the pH of acidified soil and significantly reduce the exchangeable aluminum of the soil; and the raw materials for preparation are low in price and the preparation process is simple, which has considerable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the effect of the acidified soil conditioner on the pH of the acidified soil in Experiment 1 of the present invention.

[0012] Figure 2 Schematic diagram of the effect of acidified soil conditioner on exchangeable aluminum in acidified soil in Experiment 1 of the present invention.

[0013] Figure 3 This is a schematic diagram of the effects of the acidified soil conditioner on the root length and plant height of cabbage and garlic in Experiment 2 of the present invention.

[0014] Figure 4 This is a schematic diagram of the effects of the acidified soil conditioner on the fresh weight and dry weight of cabbage and garlic in Experiment 2 of the present invention. DETAILED DESCRIPTION

[0015] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0016] Taking actual operation as an example, activated dolomite: dolomite ore produced in the northern region is used, calcined at 950°C for 1 hour, and is in powder form with a pH of 11.80, a CaO content of 58.46%, a MgO content of 37.45%, and a SiO2 content of 3.25%, and passes through a 60-mesh sieve.

[0017] Mineral humic acid: produced by weathered coal alkali method, powdered solid with purity greater than 70%, pH 9.28, conductivity 2.77 ms / cm, and organic matter content of 402.95 g / kg.

[0018] Polymer adhesive: It is an environmentally friendly material composed of organic and inorganic materials. The organic part is a cross-linked polymer material with a molecular weight of 150,000 Da, and the inorganic part is a gelling material.

[0019] Fermented organic matter: Crop straw is processed into segments less than 5 cm, and then slowly mixed with livestock and poultry manure in a ratio of 3:1 and fermented through special methods. The degree of maturity reaches 80%, the organic matter content is more than 40%, and it is homogenized through a 20-mesh sieve.

[0020] The prepared activated dolomite, mineral humic acid, polymer adhesive and fermented organic matter are uniformly mixed in a ratio of 1:0.4:0.001:0.75 by mass to obtain an acidified soil conditioner.

[0021] When used, the dosage should be selected according to the degree of soil acidification in greenhouses or orchards in the north. If the soil pH is 4.0-5.0, the dosage per mu is 150-200 kg; if the pH is 5.0-6.0, the dosage per mu is 100-150 kg. After application, the pH value of the acidified soil can be adjusted to above 7.0.

[0022] Experiment 1 employed a four-factor, three-level orthogonal design. The materials used included activated dolomite, mineral-derived humic acid, a polymer adhesive, and fermented organic matter, with three levels of each material. 300 g of test soil was mixed uniformly according to the design and then applied to the acidified soil. The soil was then incubated indoors for 30 days. During this period, the plants were watered every three days, with 60 ml of water applied each time to maintain a moisture content of approximately 20%.

[0023] The test results are as follows Figure 1 、 Figure 2 As shown in the figure, after 30 days of incubation, the soil pH of the control group CK increased by 2.15-2.65 units compared with CK; the exchangeable aluminum in the soil treated with the conditioner decreased greatly.

[0024] The synergistic effect of the conditioners is more obvious, which is mainly due to the activation of dolomite to increase the pH value of the soil, promoting the 3+Converted into aluminum hydroxide precipitation; mineral humic acid, polymer adhesives and organic components in fermented organic matter can adsorb or complex part of Al 3+ , reducing its concentration in the soil solution, while stabilizing the soil structure and preventing the precipitation of Al 3+ It is released into the soil solution again, which has the effect of reducing the exchangeable aluminum in the soil. Mineral humic acid and polymer adhesives can complex or adsorb Al 3+ The chelating effect of mineral humic acid is relatively strong, and it can 3+ Form a stable complex; the adsorption of polymer adhesives can quickly fix Al in soil solution 3+ , thereby greatly reducing the content of exchangeable aluminum in the soil.

[0025] In Experiment 2, to investigate the effects of varying soil conditioner dosages on plant growth, using pakchoi and garlic as examples, the soil conditioner prepared in the practical example was applied at low, medium, and high dosage levels. The soil conditioner was mixed evenly with the test soil according to the prescribed amount, and then 500 g per pot was used for potted planting experiments. Potted plants without soil conditioner served as the blank control (CK). Six treatments were designed, with three replicates per treatment. The soil moisture content in each pot was maintained at approximately 50% one week before planting.

[0026] The test results are as follows Figure 3 、 Figure 4 As shown, the plant height of both Chinese cabbage and garlic exhibited an initial increase followed by a decrease. Compared to the control (CK), each treatment group exhibited a certain degree of plant height improvement, with increases ranging from 29.47% to 60.1% for Chinese cabbage and 18% to 45% for garlic. The root length of the experimental plants also showed an initial increase followed by a decrease with the addition of soil conditioner, with each group showing an increase in root length compared to the blank control (CK).

[0027] All treatments increased the fresh and dry weights of pakchoi, with increases ranging from 53% to 166% for fresh weight and 25% to 98% for dry weight. The garlic-treated groups showed significant increases in both fresh and dry weight compared to the CK control group, with fresh weight increasing by 11%, 28%, 16%, 7%, and 4%, respectively, and dry weight increasing by 17%, 30%, 20%, 13%, and 7%, respectively.

[0028] Soil conditioners promote plant growth by activating dolomite to neutralize soil acidity, adjust pH, and release fixed nutrients such as P, Fe, and Zn, increasing nutrient availability. Mineral humic acid adsorbs and complexes nutrient ions, improving nutrient utilization, providing continuous fertilization, and stimulating root growth. Polymer binders retain water and nutrients, maintaining soil moisture and nutrients for root absorption.

[0029] Fermented organic matter provides organic matter and nutrients such as N, P, and K, continuously replenishing nutrients and increasing plant fresh and dry weight. Overall, soil conditioners significantly promote plant growth and development by regulating the soil environment, improving nutrient utilization, and continuously providing fertilizer.

[0030] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing an acidified soil conditioner using dolomite waste residue, characterized in that: The acidified soil conditioner is mainly composed of the following components, calculated by mass percentage: activated dolomite: mineral humic acid: polymer adhesive: fermented organic matter in a ratio of 1:0.4:0.001:0.75; the above components are evenly mixed to obtain the acidified soil conditioner.

2. The method for preparing an acidified soil conditioner using dolomite waste residue according to claim 1, wherein: The preparation method of the activated dolomite comprises the following steps: calcining the dolomite ore at a high temperature of above 900°C for 1-2 hours to obtain a powder with a pH value of above 10.0, a CaO content of above 50%, a MgO content of above 30%, and a SiO2 content of 3%. The activated dolomite is then crushed and passed through a 60-mesh sieve to obtain the activated dolomite.

3. The method for preparing an acidified soil conditioner using dolomite waste residue according to claim 1, wherein: The powdered solid is prepared by the weathered coal alkali method, has a purity greater than 70%, a pH greater than 8, an electrical conductivity greater than 2ms / cm, and an organic matter content of more than 40%.

4. The method for preparing an acidified soil conditioner using dolomite waste residue according to claim 1, wherein: The polymer adhesive is a linear polymer material with a molecular weight of 150,000 Da.

5. The method for preparing an acidified soil conditioner using dolomite waste residue according to claim 1, wherein: The preparation method of the fermented organic matter is as follows: crop straw and livestock and poultry manure are mixed in a ratio of 3:1, and the mixture is specially fermented to achieve a degree of maturity of 80%, an organic matter content of more than 40%, and is homogenized through a 20-mesh sieve.

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