Improved biological organic fertilizer for sandy soil and preparation method thereof

Abstract

This invention belongs to the field of bio-agriculture and fertilizer technology, specifically relating to a bio-organic fertilizer for improving sandy soil and its preparation method. The bio-organic fertilizer for improving sandy soil comprises peat, a water-retaining agent, bentonite, beneficial microbial agents, and water-soluble fertilizer; wherein the mass ratio of each component is: peat 85-91 parts, water-retaining agent 2-4 parts, bentonite 2-4 parts, beneficial microbial agents 2-4 parts, and water-soluble fertilizer 1-3 parts; the water-retaining agent is obtained by copolymerization of acrylate monomers, quaternary ammonium salt monomers, organosilicon coupling monomers, and cross-linking monomers. This invention's bio-organic fertilizer, by employing a specifically designed water-retaining agent component combined with peat, bentonite, beneficial microbial agents, and water-soluble fertilizer, achieves synergistic effects of enhancing soil water retention capacity, increasing soil organic matter, activating microorganisms, and improving water and fertilizer utilization.

Description

Technical Field

[0001] This invention belongs to the field of bio-agriculture and fertilizer technology, specifically relating to a bio-organic fertilizer for improving sandy soil and its preparation method. Background Technology

[0002] Sandy soils possess excellent water permeability and aeration, but they also suffer from poor water retention, rapid nutrient loss, and low fertility, making them unsuitable for stable crop growth and high yields. Therefore, soil improvement has become a significant challenge in sandy soil agriculture to enhance productivity.

[0003] Methods for improving sandy soil mainly include increasing organic fertilizer and improving soil structure through soil conditioners. For example, patent document CN106717233A describes a method for rapidly improving aeolian sandy soil by combining biochar and organic fertilizer. The method involves preparing biochar from agricultural and forestry waste; evenly spreading the prepared biochar and organic fertilizer on the surface of leveled aeolian sandy soil and evenly turning it into the soil, which can achieve long-term improvement and significantly increase productivity within 2-3 years. Patent document CN 111548796 A discloses a soil conditioner and its application method for improving the water and fertilizer retention of sandy soil. The method involves mixing biochar, bentonite, and sandy soil in a specific ratio, applying the mixture evenly to the subsoil, covering it with natural sand, adding a small amount of organic fertilizer, and then using a rotary tiller to thoroughly mix the organic fertilizer with the topsoil. Irrigation is adjusted according to soil conditions to maintain soil moisture content at 70%–80% of field capacity, facilitating the diffusion of biochar and bentonite into the sandy soil's topsoil layer and altering its texture and structure. However, this method cannot solve the problems of poor water retention and rapid nutrient loss in sandy soil, requiring intensive fertilization to maintain fertility and specific application methods, resulting in high fertilizer and labor costs. Patent document CN108129187A discloses an improved organic fertilizer for sandy saline-alkali land, comprising animal manure, plant straw, bentonite, humic acid, peach kernel powder, tobacco waste, a composite water-retaining agent, and a sand binder in a weight ratio of 40-48:12-18:8-12:8-12:6-8:6-8:3-5:2-4; and 1-3 parts by weight of microbial inoculant and 0.01-0.03 parts by weight of rooting powder. However, its composite water-retaining agent uses polyacrylic acid containing 20% ​​attapulgite clay. Although the composite with attapulgite clay can improve water retention, the network structure formed by attapulgite clay and polyacrylic acid, as well as the hydrogen bonding of acrylic acid groups, will enhance the gelation tendency of the water-retaining agent, causing the fertilizer particles to absorb water and clump together, making them difficult to disperse and effectively combine with sand particles. Although adding a sand binder can improve soil plasticity, the sand binder mainly utilizes the fact that sulfur trioxide and water in the soil can generate sulfuric acid. Sulfuric acid can react with calcium oxide in the sand to generate calcium sulfate and water, which binds tightly to the soil and cannot enhance the binding effect between fertilizer particles and soil. Summary of the Invention

[0004] The purpose of this invention is to provide a bio-organic fertilizer for improving sandy soil and its preparation method. This bio-organic fertilizer utilizes a specifically designed water-retaining agent component, exhibiting both high water-holding capacity and high anti-gelling properties. Combined with peat, bentonite, beneficial microbial agents, and water-soluble fertilizer, the resulting bio-organic fertilizer does not clump after absorbing water, but rapidly disintegrates and disperses, penetrating into the gaps between sandy soil particles. Furthermore, the water-retaining agent incorporates coupling groups with strong binding affinity to sandy soil, enhancing the binding effect between the fertilizer and sandy soil particles. Through these effects, a synergistic effect is achieved, enhancing soil water-holding capacity, increasing soil organic matter, activating microorganisms, and improving water and fertilizer utilization.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A bio-organic fertilizer for improving sandy soil is composed of peat, water-retaining agent, bentonite, beneficial microbial inoculant and water-soluble fertilizer; wherein the mass ratio of each component is: peat 85-91 parts, water-retaining agent 2-4 parts, bentonite 2-4 parts, beneficial microbial inoculant 2-4 parts, and water-soluble fertilizer 1-3 parts.

[0007] The water-retaining agent is obtained by copolymerization of acrylate monomers, quaternary ammonium salt monomers, organosilicon coupling monomers and crosslinking monomers.

[0008] Preferably, the acrylate monomer is any one of sodium acrylate, potassium acrylate, and ammonium acrylate. Ammonium acrylate is more preferred in this invention. Using ammonium acrylate can reduce soil salinity accumulation and, under the action of the compound microbial agent, can serve as a source of slow-release nitrogen fertilizer. The role of the acrylate monomer in this invention is to improve the water absorption rate of the water-retaining agent and enhance the water-holding capacity of the resulting bio-organic fertilizer.

[0009] Preferably, the quaternary ammonium salt monomer is any one of trimethylallyl ammonium chloride, acryloyloxyethyltrimethyl ammonium chloride, methacryloyloxyethyltrimethyl ammonium chloride, acrylamidopropyltrimethyl ammonium chloride, and methacrylamidopropyltrimethyl ammonium chloride. In this invention, the quaternary ammonium salt monomer plays a crucial role in the anti-gelling and agglomeration properties of the obtained water-retaining agent and the rapid disintegration and dispersion of the obtained bio-organic fertilizer after water absorption and swelling; simultaneously, it acts as a surfactant in the synthesis of the water-retaining agent, improving the polymerization effect of the organosilicon coupling monomer. The content of the quaternary ammonium salt monomer is 10%~30% of the mass of the acrylate monomer. Excessive quaternary ammonium salt monomer content will reduce the water absorption rate of the water-retaining agent and the water-holding capacity of the bio-organic fertilizer.

[0010] Preferably, the organosilicon coupling monomer is any one of methacryloxypropyltrimethoxysilane and methacryloxypropyltriethoxysilane. The organosilicon coupling monomer plays a crucial role in enhancing the binding effect between fertilizer and sand particles in this invention. The content of the organosilicon coupling monomer is 5% to 20% of the mass of the acrylate monomer. If the content of the organosilicon coupling monomer is too high, the resulting bio-organic fertilizer will have excessively strong internal binding force, which will reduce the disintegration and dispersion performance of the bio-organic fertilizer after absorbing water and swelling.

[0011] Preferably, the crosslinking monomer is N,N-methylenebisacrylamide. The role of the crosslinking monomer in this invention is to improve the water absorption rate of the water-retaining agent and the water-holding capacity of the resulting bio-organic fertilizer. The content of the crosslinking monomer is 0.02%~0.1% of the mass of the acrylate monomer. If the content of the crosslinking monomer is too high, the anti-gelling property of the resulting water-retaining agent will decrease, which will reduce the disintegration and dispersion properties of the bio-organic fertilizer after water absorption and swelling.

[0012] Preferably, the beneficial microbial agent is a compound microbial agent; the compound microbial agent includes nitrogen-fixing bacteria, Bacillus subtilis, Trichoderma, Bacillus mucilaginosus, Priestella megaterium, Bacillus polymyxa, yeast, and photosynthetic bacteria (the company's own compound microbial agent product). The combined action of these bacteria and other components of the bio-organic fertilizer activates the activity of the sandy soil.

[0013] Preferably, the water-soluble fertilizer is a macro-element water-soluble fertilizer (a water-soluble fertilizer with nitrogen, phosphorus, and potassium as the main components), and the total nutrient content of the macro-element water-soluble fertilizer is ≥50%. The use of water-soluble fertilizer rapidly increases the fertility of sandy soil.

[0014] A method for preparing a bio-organic fertilizer for improving sandy soil includes the following steps:

[0015] (1) Neutralize acrylic acid with alkaline solution to obtain acrylate monomer solution, then add deionized water, quaternary ammonium salt monomer, organosilicon coupling monomer and initiator in sequence and stir to mix evenly. Heat to 40~70℃ for polymerization reaction for 2~4h, then add crosslinking monomer and continue to keep warm for 0.5~2h. Dry the reaction mixture under vacuum and granulate to obtain water-retaining agent.

[0016] (2) The water-retaining agent obtained in step (1) is mixed with peat, bentonite, beneficial microbial agents and water-soluble fertilizer in the following mass ratio: 85-90 parts peat, 2-4 parts water-retaining agent, 2-4 parts bentonite, 2-4 parts beneficial microbial agents and 1-3 parts water-soluble fertilizer. The mixture is then granulated using a mixing granulator to obtain a bio-organic fertilizer for improving sandy soil.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) The water-retaining agent used in the bio-organic fertilizer of this invention has a high water absorption rate and anti-gelling properties. The resulting fertilizer particles have high water retention capacity and do not gel into clumps after absorbing water. They can quickly disintegrate and disperse into the gaps between sandy soil particles, thereby rapidly improving the fertility and water and fertilizer retention capacity of sandy soil.

[0019] (2) The water-retaining agent used in the bio-organic fertilizer of the present invention introduces coupling groups with strong binding force with sandy soil, which can enhance the binding effect of fertilizer components and sandy soil particles, thereby achieving the synergistic effects of better enhancing soil water holding capacity, increasing soil organic matter, activating microorganisms, and improving water and fertilizer utilization. Attached Figure Description

[0020] Figure 1 This is a physical image of the bio-organic fertilizer obtained in Example 1. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0022] Example 1

[0023] A bio-organic fertilizer for improving sandy soil is prepared as follows:

[0024] (1) 150g of acrylic acid was neutralized to neutral with 25% ammonia water to obtain ammonium acrylate monomer solution. Then, 100g of deionized water, 30g of methacrylamide propyltrimethylammonium chloride (MAPTAC), 20g of methacryloxypropyltriethoxysilane (MPS) and 0.3g of potassium persulfate were added in sequence and stirred until uniform. The mixture was heated to 50°C for 3h of polymerization reaction. Then, 0.1g of N,N-methylenebisacrylamide (MBA) was added and the reaction was continued for 1h. The reaction mixture was dried by vacuum rotary drying and granulation to obtain water-retaining agent.

[0025] (2) Prepare raw materials according to the mass ratio. Add 3 parts of water-retaining agent, 89 parts of peat, 3 parts of bentonite, 3 parts of compound microbial agent (the company's own compound microbial agent products, including nitrogen-fixing bacteria, Bacillus subtilis, Trichoderma, Bacillus mucilaginosus, Priestella megaterium, Bacillus polymyxa, yeast and photosynthetic bacteria) and 2 parts of water-soluble fertilizer (water-soluble fertilizer with a total nutrient content ≥50%) to a mixing granulator to mix and granulate, and obtain biological organic fertilizer for improving sandy soil.

[0026] The physical form of the bio-organic fertilizer obtained in this embodiment is shown in the figure below. Figure 1As shown. The water-holding capacity of the bio-organic fertilizer was measured to be 410% (water absorption to saturation / bio-organic fertilizer mass before water absorption); when saturated with water, it swelled, disintegrated, and dispersed without obvious clumping; the number of beneficial live bacteria (CFU) was 0.4 billion / g; the organic matter content was 79.0%; and the total nutrient content was 0.76%.

[0027] The application effect test of the bio-organic fertilizer obtained in this embodiment on sandy soil was conducted as follows: 100g of sandy soil was mixed evenly with 5g of bio-organic fertilizer, placed in a nylon bag and tied tightly. The bag was then immersed in water for 15 minutes, drained, and left to evaporate in the natural environment for 5 days. The soil water retention capacity was then tested (moisture content of the soil sample after 5 days of evaporation / initial moisture content of the soil sample after immersion and draining). The above immersion and evaporation process was repeated 3 times. On the 15th day, the soil nutrient retention capacity was tested (organic matter retention rate = organic matter content of the soil sample after 15 days / initial organic matter content of the soil sample after mixing with bio-organic fertilizer; total nutrient retention rate = total nutrient content of the soil sample after 15 days / initial total nutrient content of the soil sample after mixing with bio-organic fertilizer). The control group was the bio-organic fertilizer without water-retaining agent as described in this embodiment. Three parallel samples were set for each group, and the average value of the results was taken. The corresponding test results are shown in Table 1 below.

[0028] Table 1. Application Effects of Bio-organic Fertilizer

[0029] Test Sample / Performance water holding capacity Organic matter retention rate Total nutrient retention rate experimental group 26.4% 78.5% 63.6% control group 12.7% 45.1% 32.0%

[0030] As shown in Table 1, the bio-organic fertilizer of the present invention can significantly improve the water and fertilizer retention performance of sandy soil by adding a specific water-retaining agent.

[0031] Comparative Example 1 and Examples 2-3

[0032] Comparative Example 1 and Examples 2-3 were prepared by adjusting the amount of quaternary ammonium salt monomer MAPTAC added according to Table 2. The water-holding capacity, water absorption and dispersion performance, and application test results of the resulting bio-organic fertilizer in sandy soil are shown in Table 2 below.

[0033] Table 2. Effects of Quaternary Ammonium Salt Monomers on the Performance of Bio-organic Fertilizer

[0034] Test Sample / Performance MAPTAC addition amount Water retention performance Water absorption and dispersibility water holding capacity Organic matter retention rate Total nutrient retention rate Comparative Example 1 0g 580% It did not disintegrate and remained in a swollen, clumped state. 25.6% 75.2% 41.8% Example 2 15g 500% Disintegration and dispersion, with no obvious clumping 24.1% 73.5% 60.4% Example 3 45g 330% Disintegration and dispersion, with no obvious clumping 22.7% 68.2% 55.9%

[0035] As shown in Table 2, the bio-organic fertilizer obtained without the addition of quaternary ammonium salt monomers has lower anti-gelling properties. After absorbing water, it swells and clumps together, which is not conducive to the rapid disintegration and dispersion of fertilizer particles into the gaps between sandy soil particles and their binding, resulting in a faster loss of total nutrient content. Increasing the content of quaternary ammonium salt monomers reduces the water-holding capacity of the resulting bio-organic fertilizer.

[0036] Comparative Example 2 and Examples 4-6

[0037] Comparative Examples 2 and Examples 4-6 were adjusted according to Table 3 for the addition of organosilicon coupling monomer MPS. The water-holding capacity, water absorption and dispersion performance and application test results of the resulting bio-organic fertilizers in sandy soil are shown in Table 3 below.

[0038] Table 3. Effects of organosilicon coupling monomers on the performance of bio-organic fertilizers

[0039] Test Sample / Performance MPS addition amount Water retention performance Water absorption and dispersibility water holding capacity Organic matter retention rate Total nutrient retention rate Comparative Example 2 0g 380% Disintegration and dispersion, with no obvious clumping 19.6% 55.7% 45.3% Example 4 7.5g 390% Disintegration and dispersion, with no obvious clumping 23.8% 62.1% 53.5% Example 5 15g 400% Disintegration and dispersion, with no obvious clumping 25.5% 73.0% 59.8% Example 6 30g 410% Most of it disintegrated and dispersed, with a small amount clumping together. 24.7% 74.2% 50.6%

[0040] As shown in Table 3, the binding effect between the bio-organic fertilizer and sand particles was reduced when no organosilicon coupling monomer was added, resulting in a significant decrease in water retention and fertilizer retention capacity. Excessive addition of organosilicon coupling monomer resulted in bio-organic fertilizer with excessively strong internal binding forces, which reduced its disintegration and dispersion performance after water absorption and swelling.

[0041] Comparative Example 3 and Examples 7-9

[0042] Comparative Examples 3 and Examples 7-9 were adjusted according to Table 4 to increase the amount of crosslinking monomer MBA. The water-holding capacity, water absorption and dispersion properties, and application test results of the resulting bio-organic fertilizers in sandy soil are shown in Table 4 below.

[0043] Table 4. Effects of crosslinking monomers on the performance of bio-organic fertilizer

[0044] Test Sample / Performance MBA enrollment Water retention performance Water absorption and dispersibility water holding capacity Organic matter retention rate Total nutrient retention rate Comparative Example 3 0g 210% Disintegration and dispersion, with no obvious clumping 18.9% 54.3% 43.6% Example 7 0.03g 300% Disintegration and dispersion, with no obvious clumping 22.5% 64.3% 54.0% Example 8 0.05g 360% Disintegration and dispersion, with no obvious clumping 24.6% 72.5% 58.3% Example 9 0.15g 550% Most of it disintegrated and dispersed, with a small amount clumping together. 24.0% 73.5% 48.7%

[0045] As shown in Table 4, the bio-organic fertilizer obtained without the addition of cross-linking monomers has lower water-holding capacity, resulting in a significant reduction in both water retention and fertilizer retention capacity. Excessive cross-linking monomer content reduces the anti-gelling properties of the resulting water-retaining agent, thus decreasing the disintegration and dispersion properties of the bio-organic fertilizer after water absorption and swelling.

[0046] Example 10

[0047] A bio-organic fertilizer for improving sandy soil is prepared as follows:

[0048] (1) 150g of acrylic acid was neutralized to neutral with 25% ammonia water to obtain ammonium acrylate monomer solution. Then, 100g of deionized water, 20g of methacryloyloxyethyltrimethylammonium chloride, 15g of methacryloyloxypropyltrimethoxysilane and 0.3g of ammonium persulfate were added in sequence and stirred until uniform. The mixture was heated to 60℃ for polymerization reaction for 3h. Then, 0.1g of N,N-methylenebisacrylamide (MBA) was added and the reaction was continued for 1h. The reaction mixture was dried by vacuum rotary drying and granulation to obtain water-retaining agent.

[0049] (2) Prepare raw materials according to the mass ratio. Add 4 parts of water-retaining agent, 87 parts of peat, 4 parts of bentonite, 4 parts of compound microbial agent (the company's own compound microbial agent products, including nitrogen-fixing bacteria, Bacillus subtilis, Trichoderma, Bacillus mucilaginosus, Priestella megaterium, Bacillus polymyxa, yeast and photosynthetic bacteria) and 1 part of water-soluble fertilizer (water-soluble fertilizer with a total nutrient content ≥50%) to a mixing granulator to mix and granulate, and obtain biological organic fertilizer for improving sandy soil.

[0050] Example 11

[0051] A bio-organic fertilizer for improving sandy soil is prepared as follows:

[0052] (1) 150g of acrylic acid was neutralized to neutral with 25% ammonia water to obtain ammonium acrylate monomer solution. Then, 100g of deionized water, 40g of acryloyloxyethyltrimethylammonium chloride, 25g of methacryloyloxypropyltriethoxysilane and 0.3g of potassium persulfate were added in sequence and stirred until uniform. The mixture was heated to 60℃ for polymerization reaction for 3h. Then, 0.1g of N,N-methylenebisacrylamide (MBA) was added and the reaction was continued for 1h. The reaction mixture was dried by vacuum rotary drying and granulation to obtain water-retaining agent.

[0053] (2) Prepare raw materials according to the mass ratio. Add 2 parts of water-retaining agent, 91 parts of peat, 2 parts of bentonite, 2 parts of compound microbial agent (the company's own compound microbial agent products, including nitrogen-fixing bacteria, Bacillus subtilis, Trichoderma, Bacillus mucilaginosus, Priestella megaterium, Bacillus polymyxa, yeast and photosynthetic bacteria) and 3 parts of water-soluble fertilizer (water-soluble fertilizer with a total nutrient content ≥50%) to a mixing granulator to mix and granulate, and obtain biological organic fertilizer for improving sandy soil.

[0054] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. All technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A bio-organic fertilizer for improving sandy soil, characterized by comprising: It is composed of peat, water-retaining agent, bentonite, beneficial microbial inoculant and water-soluble fertilizer; wherein, the mass ratio of each component is: peat 85-91 parts, water-retaining agent 2-4 parts, bentonite 2-4 parts, beneficial microbial inoculant 2-4 parts, and water-soluble fertilizer 1-3 parts. The water-retaining agent is obtained by copolymerization of acrylate monomers, quaternary ammonium salt monomers, organosilicon coupling monomers and crosslinking monomers. The quaternary ammonium salt monomer is any one of trimethylallylammonium chloride, acryloyloxyethyltrimethylammonium chloride, methacryloxyethyltrimethylammonium chloride, acrylamidopropyltrimethylammonium chloride, and methacrylamidopropyltrimethylammonium chloride; the content of the quaternary ammonium salt monomer is 10% to 30% of the mass of the acrylate monomer; The organosilicon coupling monomer is any one of methacryloyloxypropyltrimethoxysilane and methacryloyloxypropyltriethoxysilane; the content of the organosilicon coupling monomer is 5% to 20% of the mass of the acrylate monomer.

2. The bio-organic fertilizer for improving sandy soil according to claim 1, characterized in that: The acrylate monomer is any one of sodium acrylate, potassium acrylate, or ammonium acrylate.

3. The bio-organic fertilizer for improving sandy soil according to claim 2, characterized in that: The acrylate monomer is ammonium acrylate.

4. The bio-organic fertilizer for improving sandy soil according to claim 1, characterized in that: The crosslinking monomer is N,N-methylenebisacrylamide; the content of the crosslinking monomer is 0.02% to 0.1% of the mass of the acrylate monomer.

5. The bio-organic fertilizer for improving sandy soil according to claim 1, characterized in that: The beneficial microbial agent is a compound microbial agent; the compound microbial agent includes nitrogen-fixing bacteria, Bacillus subtilis, Trichoderma, Bacillus mucilaginosa, Priestella megaterium, Bacillus polymyxa, yeast, and photosynthetic bacteria.

6. The bio-organic fertilizer for improving sandy soil according to claim 1, characterized in that: The water-soluble fertilizer is a macro-element water-soluble fertilizer; the total nutrient content of the macro-element water-soluble fertilizer is ≥50%.

7. A method for preparing a bio-organic fertilizer for improving sandy soil, characterized by, Includes the following steps: (1) Neutralize acrylic acid with alkaline solution to obtain acrylate monomer solution, then add deionized water, quaternary ammonium salt monomer, organosilicon coupling monomer and initiator in sequence and stir to mix evenly. Heat to 40~70℃ for polymerization reaction for 2~4h, then add crosslinking monomer and continue to keep warm for 0.5~2h. Dry the reaction mixture under vacuum and granulate to obtain water-retaining agent. (2) The water-retaining agent obtained in step (1) is mixed with peat, bentonite, beneficial microbial agents and water-soluble fertilizer in the following mass ratio: 85-90 parts peat, 2-4 parts water-retaining agent, 2-4 parts bentonite, 2-4 parts beneficial microbial agents and 1-3 parts water-soluble fertilizer. The mixture is then granulated using a mixing granulator to obtain a bio-organic fertilizer for improving sandy soil.

Images