A conditioning agent for targeted repair of acidified black soil and preparation method thereof

Abstract

The present invention provides a conditioning agent for targeted repair of acidified black soil, wherein the particles of the conditioning agent include a core layer and a shell layer, wherein the core layer includes alginic acid, biochemical fulvic acid and lignin, and the shell layer includes a KH2PO4 solution and oyster shell powder after low-temperature roasting. The oyster shell powder prepared by low-temperature roasting in the present invention has lower energy consumption and cost than traditional processes, less salt in the product, retains a unique organic calcium component, promotes the formation of calcium-humus complexes, can protect soil organic matter, enhance the buffering performance of black soil, improve soil acidification, and make it mild and not easy to burn seedlings; at the same time, it retains a beneficial microporous structure, ensures fertility and coordinates water vapor. Fertilizer synergists such as alginic acid, biochemical fulvic acid and lignin can improve the utilization rate of nitrogen fertilizer and the content of organic matter, while regulating the physiological metabolism of the root system and targeted repair of acidified black soil.

Description

Technical Field

[0001] The invention belongs to the field of soil conditioning, and particularly relates to a conditioning agent for targeted repair of acidified black soil and a preparation method thereof. Background Art

[0002] The black soil region is an important grain production base in my country. However, the acidification of cultivated land seriously restricts agricultural production in the region and is not conducive to the sustainable development of agriculture. The acidification of black soil is mainly due to the decline of organic matter and low nitrogen utilization rate, which leads to weakened acid buffering performance and serious nitrification acid production. Therefore, alleviating the acidification of black soil is a major problem that needs to be urgently solved and is of great significance to ensuring food security. The conventional measures to improve acidified black soil are mainly to apply lime and other materials. However, lime is inorganic calcium with a single nutrient and lack of organic nutrients. Improper application can easily cause seedling burn. Compared with inorganic calcium-type improvement materials such as lime, organic calcium-type improvement materials are rich in organic nutrients, have a mild effect on improving soil acidification, are not prone to seedling burn, and have no adverse effects when compounded with other conditioning materials. Oyster shell is such a natural organic calcium-type substance and is a good improvement material for alleviating acidification.

[0003] Oysters are the most cultivated shellfish, with an annual output of 5.81 million tons. As a by-product of aquaculture and catering, oyster shells have a huge stock and need to be developed and utilized as resources. Oyster shell materials are widely available and have broad application prospects as natural organic calcium-based soil conditioners. The main component of oyster shells is calcium carbonate, of which natural organic matter accounts for about 5%, and the main beneficial substances include chitin and amino acids; in addition, the porous structure of oyster shells has good physical properties and has good water retention, fertilizer retention, and air permeability. However, the conventional firing method of oyster shells has many problems: the conventional firing temperature is usually around 800°C, which consumes a lot of energy and is costly; it is also impossible to retain the natural organic matter in the oyster shells, and its microporous structure is destroyed, and the value of oyster shell powder in water retention and fertilizer supply is not fully utilized; in addition, the calcium oxide formed after high-temperature firing is no different from lime, has strong alkalinity, dissolves in water and releases heat, and is prone to burning seedlings when applied to the soil. In addition, the existing oyster shell soil conditioners on the market have single functions and low organic nutrient content. Most conditioners only indirectly change the acidity of the soil, and there is a lack of products that directly act on fertilizers and plants. They are less targeted, resulting in a short-lived effect on improving acidified black soil and no obvious effect on stabilizing and increasing crop yields. Summary of the invention

[0004] The purpose of the present invention is to provide a soil conditioner with high organic nutrient content, mild soil acidification improvement effect and low seedling burning, and a preparation method thereof, so as to overcome the shortcomings of existing oyster shell soil conditioners.

[0005] In order to achieve the above-mentioned purpose of the invention, the present invention provides a conditioner for targeted repair of acidified black soil and a preparation method thereof.

[0006] The present invention provides a conditioner for targeted restoration of acidified black soil. The particles of the conditioner include a core layer and a shell layer. The core layer includes alginic acid, biochemical fulvic acid and lignin, and the shell layer includes a KH2PO4 solution and low-temperature roasted oyster shell powder.

[0007] Preferably, the conditioning agent for targeted restoration of acidified black soil comprises the following components in terms of solids by weight:

[0008] 48-80 parts of low-temperature roasted oyster shell powder, 12-20 parts of alginic acid, 3-6 parts of biochemical fulvic acid and 12-22 parts of lignin.

[0009] The present invention provides a method for preparing a conditioning agent for targeted repair of acidified black soil, comprising the following steps:

[0010] Step 1) desalting and crushing the oyster shells, drying the crushed oyster shells, low-temperature roasting and cooling them, and then crushing and grinding them to obtain low-temperature roasted oyster shell powder;

[0011] Step 2) compounding alginic acid, biochemical fulvic acid and lignin, drying, grinding and granulating to obtain a core layer;

[0012] Step 3) spraying KH2PO4 solution on the surface of the core layer, and then wrapping the core layer with oyster shell powder roasted at low temperature to obtain a conditioning agent for targeted repair of acidified black soil.

[0013] Oysters grow in the ocean, and their shells contain a lot of salt. When oyster shell powder is applied to the soil, it will introduce excessive salt, causing salt stress to crops. Therefore, the present invention first desalinates the oyster shells to avoid salinization hazards caused by applying too high salt to the soil.

[0014] Preferably, the free salt content of the oyster shell after desalination treatment is controlled between 0 and 0.5 wt%.

[0015] Preferably, in step 1), the drying temperature is 60-100° C. and the drying time is 20-40 min.

[0016] Preferably, the low-temperature roasting temperature in step 1) is 250-550° C. and the low-temperature roasting time is 20-60 min.

[0017] Preferably, the particle size of the oyster shell powder after low-temperature roasting in step 1) is in the range of 20 to 50 μm.

[0018] Preferably, step 2) comprises the following steps:

[0019] S1: Weigh alginic acid, biochemical fulvic acid and lignin according to the amount, dry them, stir and mix them evenly, grind them into powder, and obtain a mixed powder with a certain degree of fineness;

[0020] S2: The mixed powder is added into an extruder for extrusion granulation, and then dried and screened to obtain a core layer.

[0021] Preferably, in step S2, the particle size of the core layer is 0.5-1 mm.

[0022] Preferably, in step 3), the KH2PO4 solution is sprayed onto the surface of the core layer using an atomizer, the concentration of the KH2PO4 solution is 1 g / L, the aperture of the atomizer nozzle is 0.1 mm, and the mist particles are 7-12 μm.

[0023] The beneficial effects of the present invention are:

[0024] (1) In the present invention, the oyster shell is desalinated to effectively control the total amount of salt, reduce the high salt stress on crops, and avoid the salinization hazard caused by too high salt in the soil.

[0025] (2) The present invention adopts a low-temperature segmented roasting process to replace the conventional 800°C calcination process, so that the oyster shells are fired evenly and without adhesion, and the roasting temperature and time are reduced, which reduces energy consumption and cost on the one hand; on the other hand, it retains the effective structure and components of the oyster shells, retains the porous structure, chitin and amino acid components of the oyster shells to the greatest extent, and reduces the strong alkalinity and heat release characteristics of the oyster shells dissolved in water. The core ingredient oyster shell powder can also promote the formation of soil aggregates, effectively protect the organic matter of black soil, improve the buffering performance of black soil, and has good fertilizer retention and water vapor regulation functions.

[0026] (3) Alginic acid in the conditioner is a biostimulant. Its unique brown algae polyphenols, fucoidan, and plant endogenous hormones such as betaine, cytokinin, gibberellin, auxin, and abscisic acid provide stimulation for crop growth, effectively promoting crop growth by promoting seed germination, root growth, and improving photosynthesis efficiency. Biochemical fulvic acid is produced through fermentation technology of aquaculture and planting waste. Its active ingredient FA has the effect of inhibiting the activity of urease and nitrifying bacteria, which can reduce the conversion efficiency of nitrogen fertilizer, play a role in slow release of nitrogen, and effectively improve the acidification of black soil caused by low utilization rate of nitrogen fertilizer. Lignin, as a complex aromatic ring structure substance, can effectively enhance the stability of organic matter in black soil compared with other easily decomposed simple alkanes and aliphatic compounds, effectively compensate for the loss of organic matter due to tillage and acidification, and exert long-term efficacy. The compounding of alginate, biochemical fulvic acid, and lignin organic materials further improves the organic nutrient content, promotes the agglomeration of conditioner particles, increases particle strength, and improves product properties.

[0027] Compounded fertilizer synergists such as alginate and biochemical humic acid can improve the utilization rate of nitrogen fertilizer, reduce nitrification and acid production, and regulate root physiological metabolism; at the same time, lignin is introduced to connect soil minerals and organic matter with the calcium bridge bonds of oyster shells, promote the cementation of aggregate structure and form aggregates, protect soil organic matter and increase the humus content, further improve the stability of black soil organic matter and acid buffering performance, and play a long-term role; in addition, it can also play the role of protecting fertilizers and supplying fertilizers, coordinating water vapor, and alleviating the physical deterioration of black soil caused by the decline of organic matter, such as associated hazards such as compaction of the plow layer.

[0028] (4) Alginate is viscous and will expand ten times when it comes into contact with water. The KH2PO4 solution is sprayed on the surface of the core layer with an atomizer, and the droplet size is controlled so that the surface of the core layer is viscous but does not expand, and can adhere to the oyster shell powder after low-temperature roasting of the shell layer. The KH2PO4 solution contains phosphorus, which can provide phosphorus fertilizer for the soil. The oyster shell powder after low-temperature roasting has a certain alkalinity. When there is moisture in the soil, the alginate expands ten times when it comes into contact with water, causing the core layer to rupture and release the alginate, biochemical fulvic acid and lignin in the core layer, which can effectively avoid the burning of seedlings. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below. The following embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0030] Example 1

[0031] A conditioning agent for targeted repair of acidified black soil, wherein the solids are calculated by weight and include the following components:

[0032] 65 parts of low-temperature roasted oyster shell powder, 15 parts of alginic acid, 4 parts of biochemical fulvic acid, and 14 parts of lignin.

[0033] Preparation method:

[0034] Step 1), washing the oyster shells with water to desalinate them, so that the free salt content of the desalted oyster shells is between 0.3wt% and 0.5wt%; crushing the desalted oyster shells into blocks of 0.5 to 3.0 cm in size, putting them into a hot air dryer, and drying them at a temperature of 60 to 100°C and a wind speed of 3 to 5 m 3 / s for 20 to 40 minutes; the dried oyster shells are transferred to a boiling furnace and low-temperature roasted and heated at 300°C for 25 minutes; the temperature is lowered to below 60°C; the oyster shells are crushed and ultrafinely crushed to obtain oyster shell powder with a particle size of 20 to 50 μm.

[0035] Step 2):

[0036] S1: Weigh alginic acid, biochemical fulvic acid and lignin according to the amount, mix them evenly in a stirring mixer, and then ball-mill them after drying to obtain a mixed powder with a grinding fineness in the range of 100 to 200 meshes;

[0037] S2: Add the mixed powder into an extruder for extrusion granulation, and then perform laser particle size detection, drying, and screening to obtain a core layer with a particle size of 0.5-1 mm.

[0038] Step 3) Use an atomizer to spray 1g / L KH2PO4 solution on the surface of the core layer, the atomization nozzle aperture is 0.1mm, and the mist particles are 7-12μm. Then, the low-temperature roasted oyster shell powder is used to wrap the core layer to obtain a conditioning agent for targeted repair of acidified black soil.

[0039] Example 2

[0040] A conditioning agent for targeted repair of acidified black soil, wherein the solids are calculated by weight and include the following components:

[0041] 45 parts of low-temperature roasted oyster shell powder, 12 parts of alginic acid, 2 parts of biochemical fulvic acid, and 10 parts of lignin.

[0042] Preparation method of oyster shell powder:

[0043] Step 1), washing the oyster shells with water to desalinate them, so that the free salt content of the desalted oyster shells is between 0.3wt% and 0.5wt%; crushing the desalted oyster shells into blocks of 0.5 to 3.0 cm in size, putting them into a hot air dryer, and drying them at a temperature of 60 to 100°C and a wind speed of 3 to 5 m 3 / s for 20 to 40 minutes; the dried oyster shells are transferred to a boiling furnace and low-temperature roasted and heated at 400°C for 40 minutes; the temperature is lowered to below 60°C; the oyster shells are crushed and ultrafinely crushed to obtain oyster shell powder with a particle size of 20 to 50 μm.

[0044] Step 2):

[0045] S1: Weigh alginic acid, biochemical fulvic acid and lignin according to the amount, mix them evenly in a stirring mixer, and then ball-mill them after drying to obtain a mixed powder with a grinding fineness in the range of 100 to 200 meshes;

[0046] S2: Add the mixed powder into an extruder for extrusion granulation, and then perform laser particle size detection, drying, and screening to obtain a core layer with a particle size of 0.5-1 mm.

[0047] Step 3) Use an atomizer to spray 1g / L KH2PO4 solution on the surface of the core layer, the atomization nozzle aperture is 0.1mm, and the mist particles are 7-12μm. Then, the low-temperature roasted oyster shell powder is used to wrap the core layer to obtain a conditioning agent for targeted repair of acidified black soil.

[0048] Example 3

[0049] A conditioning agent for targeted repair of acidified black soil, wherein the solids are calculated by weight and include the following components:

[0050] 78 parts of low-temperature roasted oyster shell powder, 18 parts of alginic acid, 5 parts of biochemical fulvic acid and 20 parts of lignin.

[0051] Step 1), washing the oyster shells with water to desalinate them, so that the free salt content of the desalted oyster shells is between 0.3wt% and 0.5wt%; crushing the desalted oyster shells into blocks of 0.5 to 3.0 cm in size, putting them into a hot air dryer, and drying them at a temperature of 60 to 100°C and a wind speed of 3 to 5 m 3 / s for 20 to 40 minutes; the dried oyster shells are transferred to a boiling furnace and low-temperature roasted and heated at a temperature of 500°C for 55 minutes; the temperature is cooled to below 60°C; the oyster shells are crushed and ultrafinely crushed to obtain oyster shell powder with a particle size of 20 to 50 μm.

[0052] Step 2):

[0053] S1: Weigh alginic acid, biochemical fulvic acid and lignin according to the amount, mix them evenly in a stirring mixer, and then ball-mill them after drying to obtain a mixed powder with a grinding fineness in the range of 100 to 200 meshes;

[0054] S2: Add the mixed powder into an extruder for extrusion granulation, and then perform laser particle size detection, drying, and screening to obtain a core layer with a particle size of 0.5-1 mm.

[0055] Step 3) Use an atomizer to spray 1g / L KH2PO4 solution on the surface of the core layer, the atomization nozzle aperture is 0.1mm, and the mist particles are 7-12μm. Then, the low-temperature roasted oyster shell powder is used to wrap the core layer to obtain a conditioning agent for targeted repair of acidified black soil.

[0056] Comparative Example 1

[0057] A conditioning agent for targeted repair of acidified black soil, wherein the solids are calculated by weight and include the following components:

[0058] 65 parts of low-temperature roasted oyster shell powder, 15 parts of alginic acid, 4 parts of biochemical fulvic acid, and 14 parts of lignin.

[0059] Step 1), washing the oyster shells with water to desalinate them, so that the free salt content of the desalted oyster shells is between 0.3wt% and 0.5wt%; crushing the desalted oyster shells into blocks of 0.5 to 3.0 cm in size, putting them into a hot air dryer, and drying them at a temperature of 60 to 100°C and a wind speed of 3 to 5 m 3 / s for 20 to 40 minutes; the dried oyster shells are transferred to a boiling furnace and low-temperature roasted and heated at 800°C for 25 minutes; the temperature is lowered to below 60°C; the oyster shells are crushed and ultrafinely crushed to obtain oyster shell powder with a particle size of 20 to 50 μm.

[0060] Step 2):

[0061] S1: Weigh alginic acid, biochemical fulvic acid and lignin according to the amount, mix them evenly in a stirring mixer, and then ball-mill them after drying to obtain a mixed powder with a grinding fineness in the range of 100 to 200 meshes;

[0062] S2: Add the mixed powder into an extruder for extrusion granulation, and then perform laser particle size detection, drying, and screening to obtain a core layer with a particle size of 0.5-1 mm.

[0063] Step 3) Use an atomizer to spray 1g / L KH2PO4 solution on the surface of the core layer, the atomization nozzle aperture is 0.1mm, and the mist particles are 7-12μm. Then, the low-temperature roasted oyster shell powder is used to wrap the core layer to obtain a conditioning agent for targeted repair of acidified black soil.

[0064] In order to explain the present invention more clearly, the soil conditioners prepared in Examples 1 to 3 of the present invention and Comparative Example 1 were tested and compared in terms of performance, and the following experiment was designed.

[0065] Experiment 1: Comparison of physical and chemical indicators of soil conditioner products

[0066] 1. Test materials

[0067] Oyster shell powder after low-temperature roasting prepared in Example 1, Example 2, Example 3 and Comparative Example 1.

[0068] 2. Detection Methods

[0069] pH (H2O): 10 g of oyster shell powder after low-temperature roasting was mixed with 50 mL of deionized water, stirred for 2 min and then allowed to stand. The pH value of the conditioner was measured by a pH potentiometer;

[0070] Porosity: According to GB T 21650.3-2011 “Determination of pore size distribution and porosity of solid materials by mercury intrusion and gas adsorption method Part 2: Analysis of mesopores and macropores by gas adsorption method”, nitrogen isothermal adsorption-desorption curves were used to characterize the porosity of oyster shell powder.

[0071] Chitosan content: The chitosan content of soil conditioner is determined according to GB 29941-2013 "Food Additive Chitosan (Chitosan)";

[0072] Amino acid content: The amino acid content of soil conditioners is determined according to NY / T 1975-2010 "Determination of free amino acid content of water-soluble fertilizers".

[0073] 3. Results and Analysis

[0074] The pH (H2O), pore size, and chitosan and amino acid contents of oyster shell powder and conditioning products are shown in Table 1.

[0075] Table 1 Physicochemical properties of oyster shell powder and nutritional content of conditioner products under different roasting process conditions

[0076] index Example 1 Example 2 Example 3 Comparative Example <![CDATA[pH(H2O)]]> 8.24 8.72 9.63 11.60 <![CDATA[Porosity (cm 3 / g)]]> 0.215 0.156 0.108 0.041 Chitosan content (g / kg) 0.32 0.25 0.19 0.15 Amino acid content (g / kg) 6.59 4.12 3.05 1.06

[0077] It can be seen from Table 1 that the alkalinity of the oyster shell powder prepared by low temperature roasting in Examples 1 to 3 of the present invention is reduced, the pH (H2O) is reduced to 8.24, and the porosity is increased by 4.24 times; the chitosan content of Examples 1 to 3 is increased by 113%, and the amino acid content is increased by 521.7%. The present invention effectively improves the physical and chemical properties of the oyster shell powder and retains nutrients.

[0078] Experiment 2: Comparison of black soil acidification improvement effects

[0079] 1. Experimental design method

[0080] An experiment was conducted in an acidified black soil test field somewhere in the corn planting belt of Jilin Province. The conditioners prepared in Examples 1 to 3 and the comparative examples were used to improve the acidified black soil. A randomized block design method was used, with a total of 4 treatments and 3 repetitions. According to local conventional tillage and fertilization measures, the conditioners prepared in Examples 1 to 3 and the comparative examples were applied at a one-time rate of 50 kg / mu into the tillage layer soil with a depth of about 12 to 20 cm. One month after the soil conditioner was applied, the corn variety Liaoyu No. 1, which was widely promoted locally, was selected for sowing in the test field, with a row spacing of 45 cm, a plant spacing of 25 cm, and a sowing depth of 5 to 10 cm. Base fertilizer application method: 13 to 15 kg N / mu, 4 to 5 kg P2O5 / mu, 5 to 6 kg K2O / mu, and a fertilization depth of 12 to 20 cm. The remaining field management measures were kept consistent with local traditional methods. After corn harvest, 0-20 cm soil samples were collected, air-dried and sieved, and the pH, organic matter, germination rate and yield were measured respectively to compare and evaluate the targeted repair and improvement effects of the soil conditioner on black soil.

[0081] 2. Detection Method

[0082] Soil pH: 10 g of soil sample was mixed with 25 mL of deionized water, stirred for 1 min, and then allowed to stand. The soil pH was measured using a pH potentiometer.

[0083] Soil organic matter determination: Determine according to the soil organic matter detection method in "Soil Agrochemical Analysis" by Bao Shidan.

[0084] 3. Results and Analysis

[0085] Soil pH and organic matter content are shown in Table 2.

[0086] Table 2 Soil physical and chemical indicators under different compound ratios

[0087]

[0088] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A conditioning agent for targeted restoration of acidified black soil, wherein the particles of the conditioning agent include a core layer and a shell layer, the core layer includes alginic acid, biochemical fulvic acid and lignin, and the shell layer includes a KH2PO4 solution and oyster shell powder after low-temperature roasting, wherein the low-temperature roasting is constant temperature roasting at 250-550°C; The solid content of the conditioning agent is calculated by weight and includes the following ingredients: 48-80 parts of low-temperature roasted oyster shell powder, 12-20 parts of alginic acid, 3-6 parts of biochemical fulvic acid and 12-22 parts of lignin.

2. A method for preparing a conditioning agent for targeted restoration of acidified black soil, characterized in that: The following steps are involved: Step 1) desalting and crushing the oyster shells, drying the crushed oyster shells, low-temperature roasting and cooling them, and then crushing and grinding them to obtain low-temperature roasted oyster shell powder; Step 2) compounding alginic acid, biochemical fulvic acid and lignin, drying, grinding and granulating to obtain a core layer; Step 3) spraying KH2PO4 solution on the surface of the core layer, and then wrapping the core layer with oyster shell powder roasted at low temperature to obtain a conditioning agent for targeted repair of acidified black soil.

3. The method for preparing a conditioning agent for targeted repair of acidified black soil according to claim 2, characterized in that: The free salt content of the oyster shell after desalting in step 1) is controlled between 0 and 0.5 wt%.

4. The method for preparing a conditioning agent for targeted repair of acidified black soil according to claim 2, characterized in that: The drying temperature in step 1) is 60-100° C. and the drying time is 20-40 min.

5. The method for preparing a conditioning agent for targeted repair of acidified black soil according to claim 2, characterized in that: The low-temperature roasting temperature in step 1) is 250-550° C. and the low-temperature roasting time is 20-60 minutes.

6. The method for preparing a conditioning agent for targeted repair of acidified black soil according to claim 2, characterized in that: The particle size of the oyster shell powder after low-temperature calcination in step 1) is in the range of 20 to 50 μm.

7. The method for preparing a conditioning agent for targeted repair of acidified black soil according to claim 2, characterized in that: Step 2) includes the following steps: S1: Weigh alginic acid, biochemical fulvic acid and lignin according to the amount, dry them, stir and mix them evenly, grind them into powder, and obtain a mixed powder with a certain degree of fineness; S2: The mixed powder is added into an extruder for extrusion granulation, and then dried and screened to obtain a core layer.

8. The method for preparing a conditioning agent for targeted repair of acidified black soil according to claim 7, characterized in that: In step S2, the particle size of the core layer is 0.5-1 mm.

9. The method for preparing a conditioning agent for targeted repair of acidified black soil according to claim 2, characterized in that: In step 3), a KH2PO4 solution is sprayed onto the surface of the core layer using an atomizer, the concentration of the KH2PO4 solution is 1 g / L, the aperture of the atomizer nozzle is 0.1 mm, and the mist particles are 7-12 μm.

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