Pepper rooting promoting fertilizer and its production process

Abstract

The present application relates to the technical field of agricultural fertilizer, and particularly relates to a pepper root-promoting fertilizer and a production process thereof. The pepper root-promoting fertilizer takes steel slag micro-powder and diatomite as carriers, combines with a bioactive zinc peptide compound liquid peptide, a high-activity bacteria concentration Bacillus subtilis fermentation liquid activated by seaweed extract, humic acid, water-soluble potassium, and a dual-function additive system compounded by high-molecular-weight polyglutamic acid and sodium lignosulfonate, is mixed and granulated through specific process sequence and parameters, and is dried through three-stage gradient temperature drying to form a granular fertilizer. The present application creatively realizes four technical fusions of waste material resourceization, nutrient bio-chelation, microbial functionalization and controllable physical structure, solves technical problems such as the harm of metal impurities in steel slag, the easy fixation of traditional trace elements in soil, the insufficient planting force of microbial fertilizer, and the easy hardening and poor disintegration of granular fertilizer, and significantly promotes the growth of pepper root system, enhances the stress resistance of plants, and improves the resource utilization rate and cultivation benefit.

Description

Technical Field

[0001] This invention relates to the field of agricultural fertilizer technology, specifically to a granular fertilizer that combines nutrient supply, root growth stimulation, and soil improvement functions, particularly a special root-promoting fertilizer prepared using industrial solid waste resources to promote the root growth and development of chili peppers, and its production process. Background Technology

[0002] As a widely cultivated economic crop globally, the root system development of chili peppers directly determines the plant's nutrient absorption efficiency, stress resistance, and final yield. Roots are not only organs for absorbing water and minerals but also synthesize various plant hormones to regulate plant growth. Therefore, promoting robust root growth in chili peppers is one of the core aspects of improving cultivation efficiency. In chili pepper cultivation, fertilization is a key measure for regulating root development. However, traditional fertilizers often focus on supplying macronutrients such as nitrogen, phosphorus, and potassium, while neglecting micronutrients, organic nutrients, and the synergistic effects of microorganisms, leading to an imbalance in the nutrients required for root growth.

[0003] With the advancement of the concept of sustainable agricultural development, the resource utilization of industrial waste has become an industry trend. Steel slag, a major waste product of the steel industry, is rich in medium-level elements such as silicon and calcium. These elements play an important role in strengthening root cell walls and promoting cell division. However, the metal fragments and large particle size contained in steel slag limit its direct application. Improper handling can lead to soil pollution or low nutrient utilization. Meanwhile, existing root-promoting fertilizers generally suffer from problems such as rapid nutrient release, easy soil fixation, and limited functionality. For example, trace elements such as inorganic zinc easily bind with soil components and become ineffective; ordinary organic fertilizers lack slow-release mechanisms, leading to nutrient loss; and the survival and colonization capacity of beneficial microorganisms in fertilizers is insufficient, making it difficult to fully exert their growth-promoting and antibacterial effects. Furthermore, the physical properties of fertilizers also affect their application effect. Problems such as particle clumping and poor disintegration reduce the contact efficiency between roots and nutrients, further restricting the improvement of root-promoting effects.

[0004] Therefore, developing a multifunctional root-promoting fertilizer for chili peppers that can synergistically utilize industrial waste, integrate bioactive substances and functional microorganisms, and possess excellent physical slow-release properties is of great significance for improving the efficiency of chili pepper cultivation and promoting the green and sustainable development of agriculture. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a chili root-promoting fertilizer and its production process. The fertilizer is produced by finely processing steel slag waste and combining it with a diatomaceous earth carrier, along with components such as an organic zinc peptide complex and Bacillus subtilis activation liquid. The process involves mixing, granulation, and staged drying to create the chili root-promoting fertilizer. This solves the problems of low micronutrient absorption efficiency, insufficient utilization of industrial waste, poor microbial activity, and suboptimal particle physical properties in traditional fertilizers, as well as nutritional imbalances and weak stress resistance in chili root growth. Specifically, this is achieved through the following technical solution.

[0006] This invention provides a production process for a root-promoting fertilizer for chili peppers. The core of this process lies in the synergistic design and precise control of multiple components and processes, including the following steps:

[0007] Step 1: Select steel slag waste with SiO2 content ≥25% and CaO content ≥30%, and successively crush, air jet mill, screen and magnetic separation to obtain steel slag powder; select diatomite ore with SiO2 content ≥85%, crush, dry and cool to obtain diatomite.

[0008] Step 2: Using fermented soybean meal with a protein content ≥45% as raw material, deionized water and protease are added for enzymatic hydrolysis to obtain an enzymatic hydrolysate rich in small molecule peptides; then the enzymatic hydrolysate is mixed with zinc sulfate and chelated to obtain a bioactive zinc peptide complex solution.

[0009] Step 3: Mix Bacillus subtilis inoculant, seaweed extract and sterile deionized water, place in a sterile fermentation tank for fermentation and activation, and obtain microbial activated liquid;

[0010] Step 4: Add the steel slag powder obtained in Step 1, diatomaceous earth and humic acid, water-soluble potassium and the bioactive zinc peptide composite liquid obtained in Step 2 into a mixer and mix until uniform.

[0011] Step 5: Add the microbial activation liquid obtained in Step 3, sodium lignosulfonate as a dispersing agent, and high molecular weight polyglutamic acid as a functional agent to the mixture in Step 4 in sequence. When adding, first add the dispersing agent and stir for a short time to pre-disperse, then add the functional agent and continue stirring. At the same time, spray deionized water to adjust the moisture content of the mixture to 25% to 30% to obtain functionalized wet mixture.

[0012] Step 6: Feed the functionalized mixed wet material into a disc granulator for granulation, screen out wet particles with a particle size of 2-4 mm, and return unqualified particles to the mixing process in step 5.

[0013] Step 7: After spreading the wet granules, dry them using a three-stage gradient temperature drying process; after drying, cool the granules and sieve out qualified granules with a particle size of 2-4mm to obtain the chili root-promoting fertilizer. Unqualified granules are returned to step 5 for recycling.

[0014] Preferably, in step 1, a jaw crusher is used for crushing, and the coarse powder particle size after crushing is ≤5mm;

[0015] The air jet mill is used for pulverization, with a pulverization pressure of 0.8 MPa and a feed rate of 100 kg / h; sieving is performed using a 200-mesh standard sieve.

[0016] The magnetic separation uses a permanent magnet drum separator, with the magnetic field strength set at 10000~12000Gs and the processing rate at 100kg / h.

[0017] Preferably, in step 1, the diatomaceous earth is dried under the following conditions: temperature 100-120℃, time 2-3h, and spreading thickness ≤5cm.

[0018] Preferably, in step 2, the mass ratio of fermented soybean meal, deionized water, and protease is 1:4-6:0.003-0.008;

[0019] The enzymatic hydrolysis conditions were: pH 6.0–6.5, temperature 45–55℃, stirring speed 80–120 r / min, and hydrolysis time 2 h.

[0020] The mass ratio of fermented soybean meal to zinc sulfate was 1:0.8-1.2. The chelation reaction conditions were: temperature 30-40℃, stirring speed 100-150 r / min, and chelation time 3h.

[0021] Preferably, in step 3, the concentration of Bacillus subtilis in the Bacillus subtilis inoculant is ≥500 million CFU / g, and the content of alginate in the seaweed extract is ≥15%;

[0022] The mass ratio of Bacillus subtilis inoculum, seaweed extract, and deionized water is 2:1:3;

[0023] Before fermentation, the stainless steel fermentation tank was sterilized at 121℃ for 30 minutes, and the deionized water was sterilized by ultraviolet light.

[0024] The fermentation conditions were: temperature 25–35℃, rotation speed 100–150 r / min, aeration rate 0.5 vvm, and fermentation time 6–8 h.

[0025] Preferably, in step 4, the humic acid contains HA ≥ 70%, and the water-soluble potassium is one or more of potassium sulfate, potassium chloride, or potassium nitrate, with a potassium content of ≥ 50% calculated as K2O.

[0026] The mass ratio of steel slag powder, diatomaceous earth, humic acid, water-soluble potassium, and bioactive zinc-titanium composite solution is 30-45:10-18:8-12:5-10:1-3.

[0027] During mixing, set the mixer speed to 300-350 r / min and the mixing time to 15 min.

[0028] Preferably, in step 5, the functional additive is polyglutamic acid with an average relative molecular mass of 1 million to 2 million, and the dispersing agent is sodium lignosulfonate.

[0029] The mass ratio of the added microbial activating liquid, functional additives, dispersing agents to the added steel slag powder is 5-7:0.5-1.5:2-4:30-45;

[0030] When adding, first add the dispersing agent and stir at 300 r / min for 2 minutes, then add the functional agent and continue stirring for 8 minutes.

[0031] Preferably, in step 6, the disc granulator is set with an inclination angle of 35°, a rotation speed of 40-50 r / min, and a feeding speed of 45-50 kg / h;

[0032] During screening, fine particles <2mm are returned directly to the mixer, while coarse particles >4mm are crushed and then returned to the mixer.

[0033] Preferably, in step 7, the wet particles are evenly spread on the conveyor belt of the belt dryer, with a thickness of 3-5 cm;

[0034] The parameters for the staged drying are as follows: the first stage drying temperature is 35℃, the wind speed is 1.5m / s, and the time is 30min; the second stage drying temperature is 45℃, the wind speed is 2.0m / s, and the time is 40min; the third stage drying temperature is 55℃, the wind speed is 2.5m / s, and the time is 30min.

[0035] The screening process uses a double-layer screen with an upper mesh size of 4mm and a lower mesh size of 2mm. Coarse particles with a diameter >4mm are crushed and then returned to the mixer for recycling along with fine particles with a diameter <2mm.

[0036] This invention also provides a chili root-promoting fertilizer, which is prepared according to the production process of the chili root-promoting fertilizer described above.

[0037] After adopting the above technical solution, the beneficial effects of the present invention are:

[0038] 1. To realize the resource utilization of industrial waste, reduce production costs and reduce environmental pressure. The silicon and calcium elements in steel slag are released efficiently after fine treatment. Combined with the porous carrier characteristics of diatomaceous earth, it provides a stable supply of medium-quantity elements for chili pepper roots, enhancing root resistance and growth vitality.

[0039] 2. By combining the enzymatic hydrolysis of soybean meal to produce peptides with zinc chelation, a zinc peptide complex is prepared, which has both nutritional and hormonal functions, making its root-promoting effect significantly better than that of a simple physical mixture of inorganic zinc and organic matter.

[0040] 3. Through fermentation and activation of Bacillus subtilis and seaweed extract, a stable microbial growth-promoting system is constructed. The protective film formed by beneficial microorganisms can inhibit pathogens, and the secreted plant hormones can effectively promote root growth. Seaweed extract can also improve the physical and chemical properties of the soil and enhance the root system's ability to absorb water and fertilizer.

[0041] 4. Optimizing fertilizer formulation and production process, the synergistic effect of functional additives and dispersants improves the physical properties of fertilizer, resulting in uniform and stable granules with good disintegration and dispersibility, avoiding clumping and nutrient loss. The staged drying and circulating granulation process ensures product quality and improves the contact efficiency between nutrients and roots.

[0042] 5. Through process design, mineral nutrients, organic active substances, functional microorganisms and physical regulators work synergistically in time and space to provide nutrition, stimulate growth, improve the environment and inhibit diseases, etc., and work together to promote the growth of pepper roots, resulting in a comprehensive and stable growth-promoting effect. Detailed Implementation

[0043] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the invention.

[0044] An embodiment of the present invention provides a production process for a root-promoting fertilizer for chili peppers, specifically including the following steps:

[0045] Step 1

[0046] Steel slag waste with SiO2 content ≥25% and CaO content ≥30% was selected and crushed into coarse powder with a particle size ≤5mm using a jaw crusher. The coarse powder was then fed into an air jet mill for further pulverization and sieved through a 200-mesh standard sieve. The undersize material was then fed into a permanent magnet drum separator to remove metal debris, yielding steel slag fine powder for later use. Diatomaceous earth ore with SiO2 content ≥85% was selected and crushed into mineral sand with a particle size ≤10mm using a jaw crusher. The sand was then evenly spread on a tray, placed in an electric constant temperature oven for drying, and naturally cooled to room temperature, yielding diatomaceous earth for later use.

[0047] Among them, the air jet mill has a grinding pressure of 0.8MPa and a feeding rate of 100kg / h, while the permanent magnet drum magnetic separator has a magnetic field strength of 10000~12000Gs and a processing rate of 100kg / h.

[0048] The thickness of the ore on the tray is ≤5cm. The drying temperature of the electric heating constant temperature oven is set to 100~120℃ and the drying time is 2~3h. This process can ensure that the hot airflow penetrates the material layer and promotes uniform and rapid drying of moisture.

[0049] Among them, steel slag waste with SiO2 content ≥25% and CaO content ≥30% is mainly made from converter slag or electric furnace slag after aging and stabilization treatment. In addition, the steel slag is preferably made from waste generated in the production of high silicon alloy materials to ensure that the silicon and calcium content meets the above requirements.

[0050] In the process described above, the content of heavy metal elements such as chromium, nickel, vanadium, lead, and cadmium in the steel slag waste should meet the national standard limits to reduce the negative impact on the rooting of chili peppers.

[0051] In the above steps, steel slag is used as the raw material for the production of this fertilizer. Steel slag is an industrial waste, and recycling it can reduce production costs and achieve resource recycling. At the same time, its rich silicon and calcium are essential medium elements for the growth of chili pepper roots. Silicon can enhance the strength of root cell walls and improve stress resistance; calcium can promote root cell division and elongation and reduce the risk of root rot.

[0052] A jaw crusher is used for coarse crushing to meet the feeding requirements of the air jet mill; then, the air jet mill uses high-speed airflow to achieve ultrafine crushing, increasing the specific surface area of ​​the steel slag, improving the leaching efficiency of silicon and calcium elements, and facilitating absorption by the chili root system.

[0053] In addition, the strong magnetic field of the permanent magnet drum separator is used to adsorb metal fragments such as iron and manganese in the steel slag. Removing iron-based metal fragments is to avoid mechanical damage or contamination to the chili roots after they come into contact with metal impurities, and to ensure the healthy growth of the roots.

[0054] Diatomaceous earth has a porous structure, making it an excellent carrier material. Its high SiO2 content can supplement the silicon element needed for the growth of chili pepper roots. At the same time, its porous structure can adsorb other nutrients in fertilizers, achieving slow release of nutrients and preventing nutrient loss.

[0055] The drying process is to remove free water and crystal water from diatomaceous earth, preventing material clumping due to excessive moisture during subsequent mixing. Furthermore, the porous structure after drying has stronger adsorption properties, which can further enhance the slow-release effect of the waste.

[0056] Step 2

[0057] Fermented soybean meal was taken, deionized water was added, and protease was added. Enzymatic hydrolysis was carried out for 2 hours at pH 6.0-6.5, temperature 45-55℃ and stirring speed 80-120 r / min to obtain polypeptide solution. The polypeptide solution was mixed with zinc sulfate and chelated for 3 hours at temperature 30-40℃ and stirring speed 100-150 r / min to obtain bioactive zinc peptide complex solution for later use.

[0058] The fermented soybean meal has a protein content of ≥45%, and the mass ratio of the added fermented soybean meal, deionized water, and protease is 1:4~6:0.003~0.008.

[0059] The protease is a neutral protease, and the protease activity is preferably ≥100,000 U / g.

[0060] In the above steps, the mass ratio of fermented soybean meal to zinc sulfate is 1:0.8 to 1.2.

[0061] The zinc element introduced in this step is an essential trace element for the growth of chili pepper roots. It participates in the metabolic regulation of plant growth hormones and the regulation of root enzyme activity. A lack of zinc will lead to short roots and difficulty in rooting.

[0062] The above steps involve enzymatic hydrolysis of fermented soybean meal by proteases. Under the action of proteases, the peptide bonds in the fermented soybean meal are broken to generate small polypeptides. The amino and carboxyl functional groups in the polypeptides can form stable chelates with zinc ions. Compared with inorganic zinc, chelated zinc is more stable, less likely to be fixed by the soil, and can be directly absorbed by the roots of peppers, thus improving the utilization rate of zinc. At the same time, the polypeptides themselves are a high-quality organic nitrogen source, which can promote the growth of root cells.

[0063] Step 3

[0064] Add Bacillus subtilis inoculant and seaweed extract to a stainless steel fermenter, add deionized water, stir until dissolved, set the temperature to 25-35℃, the rotation speed to 100-150 r / min, the aeration rate to 0.5 vvm, and ferment for 6-8 hours to obtain the microbial activated liquid for later use.

[0065] The stainless steel fermentation tank needs to be sterilized at 121°C for 30 minutes before feeding, and the deionized water needs to be sterilized with ultraviolet light before feeding to prevent miscellaneous bacteria from competing with Bacillus subtilis for nutrients and living space, and to ensure the normal proliferation of Bacillus subtilis.

[0066] Among them, the concentration of Bacillus subtilis in the above-mentioned Bacillus subtilis inoculant is ≥500 million CFU / g, and the content of alginate in the seaweed extract is ≥15%.

[0067] In the above steps, the mass ratio of Bacillus subtilis inoculant, seaweed extract, and deionized water is 2:1:3.

[0068] The Bacillus subtilis introduced in the above steps is a beneficial rhizosphere microorganism that can colonize the surface of pepper roots, secrete antibacterial substances to inhibit the reproduction of pathogens, and at the same time secrete plant hormones such as auxin and gibberellin to promote root growth.

[0069] Alginic acid in seaweed extract can regulate the physical and chemical properties of soil, enhance the root system's ability to absorb water and fertilizer, and can also serve as a carbon source for Bacillus subtilis. Through fermentation and activation, Bacillus subtilis can be transformed from a dormant state to an active state, thereby improving its colonization ability and activity in the soil.

[0070] Step 4

[0071] Add the steel slag powder and diatomaceous earth obtained in step 1, the bioactive zinc peptide composite liquid obtained in step 2, humic acid, and water-soluble potassium into a mixer, set the speed to 300-350 r / min, and mix for 15 min.

[0072] Among them, humic acid contains HA≥70%, and water-soluble potassium is one or more of potassium sulfate, potassium chloride or potassium nitrate, with potassium content ≥50% calculated as K2O.

[0073] The mass ratio of steel slag powder, diatomaceous earth, bioactive zinc peptide composite liquid, humic acid, and water-soluble potassium added in the above steps is 30-45:10-18:1-3:8-12:5-10.

[0074] This step involves uniformly mixing mineral nutrients, organic nutrients, and carrier materials to provide comprehensive and balanced basic nutrition for the growth of chili pepper roots.

[0075] The humic acid in the soil can improve soil aggregate structure, enhance soil water and fertilizer retention capacity, and promote the dissolution of mineral elements; water-soluble potassium can enhance root vitality and improve the drought and disease resistance of chili peppers.

[0076] Step 5

[0077] Continue adding microbial activation liquid, functional additives, and dispersing agents to the mixer, maintaining a speed of 300 r / min and stirring for 10 min to obtain a mixed wet material.

[0078] During the mixing process, deionized water is sprayed into the mixer multiple times until the moisture content of the mixed wet material reaches 25% to 30%, providing suitable humidity conditions for subsequent granulation.

[0079] Among them, the above-mentioned functional additive is polyglutamic acid with an average relative molecular mass of 1 million to 2 million, and the dispersing agent is sodium lignosulfonate. During the addition process, the dispersing agent is added first, and the functional additive is added after stirring for 2 minutes. After adding the functional additive, stirring is continued for 8 minutes. Adding the dispersing agent first can disperse the base material in advance and avoid the functional additive from agglomerating.

[0080] In the above steps, the mass ratio of the added microbial activating liquid, functional additives, dispersing agents and added steel slag powder is 5-7:0.5-1.5:2-4:30-45.

[0081] This step further enhances the root-promoting effect and physical properties of the fertilizer by adding microbial activation liquid, functional additives, and dispersing agents. Sodium lignosulfonate, a dispersing agent, can prevent material clumping, improve the dispersibility of fertilizer in the soil, and facilitate root contact. Polyglutamic acid, a functional additive, can chelate nutrients in the soil, prolong the nutrient release cycle, and enhance the root's water absorption capacity.

[0082] Step 6

[0083] The mixed wet material obtained in step 5 is fed into a disc granulator for granulation. The wet particles of 2-4 mm are collected by screening through a 2-4 mm screen. Fine particles <2 mm are returned to the mixer, and coarse particles >4 mm are crushed and returned to the mixer.

[0084] The disc granulator is set with an inclination angle of 35°, a rotation speed of 40-50 r / min, and a feeding speed of 45-50 kg / h.

[0085] This step is the granulation process of the chili root-promoting fertilizer. Granulation is to process the mixed wet material into granular fertilizer that is easy to store, transport and apply. The particle size of 2-4 mm is suitable for the distribution area of ​​chili roots and can be evenly dispersed around the roots to improve nutrient utilization. In addition, unqualified particles after screening are returned for recycling to reduce raw material loss.

[0086] Step 7

[0087] The collected wet granules with a particle size of 2-4 mm are evenly spread on the conveyor belt of a belt dryer and dried in stages. After drying, the granules are cooled at room temperature and then fed into a vibrating screen. The granules are graded using a 2-4 mm double-layer screen. Coarse granules with a particle size >4 mm are crushed and returned to the mixer for recycling along with fine granules with a particle size <2 mm. The qualified granules with a particle size of 2-4 mm are collected as the final product, chili root-promoting fertilizer.

[0088] The wet particles are laid on the conveyor belt of the belt dryer with a thickness of 3 to 5 cm.

[0089] The drying process is carried out in stages as follows: the first stage is drying at 35℃ with a wind speed of 1.5m / s for 30 minutes; the second stage is drying at 45℃ with a wind speed of 2.0m / s for 40 minutes; and the third stage is drying at 55℃ with a wind speed of 2.5m / s for 30 minutes.

[0090] The upper screen of the double-layer screen has a mesh size of 4mm, and the lower screen has a mesh size of 2mm.

[0091] In this process, staged drying can prevent the surface of wet granules from cracking due to rapid heating, ensuring the integrity of the granule structure, while reducing the moisture content of the granules and preventing mold growth during storage.

[0092] Cooling followed by sieving and grading can further ensure uniform particle size, improve product quality, and recycle unqualified particles to the previous process, thereby maximizing resource utilization.

[0093] To facilitate a further understanding of the present invention, several embodiments and comparative examples are given below.

[0094] Example 1

[0095] Step 1: Select steel slag waste with SiO2 content of 26% and CaO content of 35%, crush it into coarse powder with a particle size of 5mm using a jaw crusher, and then feed the coarse powder into an air jet mill. Set the crushing pressure to 0.8MPa and the feeding rate to 100kg / h for crushing. After crushing, sieve through a 200-mesh standard sieve and collect the undersize material. Send the undersize material into a permanent magnet drum magnetic separator. Set the magnetic field strength to 12000Gs and the processing rate to 100kg / h to remove metal debris and obtain steel slag fine powder for later use. Select diatomaceous earth ore with SiO2 content of 88%, crush it into mineral sand with a particle size of 8mm using a jaw crusher, spread the mineral sand evenly on a tray with a thickness of 4cm, and place it in an electric heating constant temperature oven. Set the drying temperature to 110℃ and the drying time to 2.5h for drying. After drying, let it cool naturally to room temperature to obtain diatomaceous earth for later use.

[0096] Step 2: Weigh 50g of fermented soybean meal with a protein content of 48% and place it in a reaction vessel. Add 250g of deionized water and 0.25g of neutral protease with an activity of 120,000 U / g. Adjust the pH of the system to 6.0, set the temperature to 50℃ and the stirring speed to 100r / min for 2 hours to obtain a polypeptide solution. Add 50g of zinc sulfate to the polypeptide solution, set the temperature to 35℃ and the stirring speed to 120r / min for 3 hours to obtain a bioactive zinc peptide complex solution for later use.

[0097] Step 3: Sterilize the stainless steel fermentation tank at 121℃ for 30 minutes, and simultaneously sterilize 360g of deionized water with ultraviolet light.

[0098] 200g of Bacillus subtilis inoculum with a concentration of 600 million CFU / g and 120g of seaweed extract with an alginate content of 18% were added to a sterilized stainless steel fermenter. 360g of sterilized deionized water was added and stirred until dissolved. The fermentation was carried out at a temperature of 30℃, a rotation speed of 120r / min, and an aeration rate of 0.5vvm for 7 hours to obtain a microbial activation solution for later use.

[0099] Step 4: Add 4700g of steel slag powder, 1500g of diatomaceous earth, 1000g of 75% humic acid (HA), 800g of potassium sulfate with a potassium content of 52% (calculated as K2O), and 200g of bioactive zinc peptide composite liquid into a mixer. Set the mixer speed to 320r / min and mix for 15min.

[0100] Step 5: Add 250g of sodium lignosulfonate to the mixer, stir at 300r / min for 2min, then add 80g of polyglutamic acid with a molecular weight of 1.5 million, and continue stirring for 8min.

[0101] During the mixing process, deionized water was sprayed into the mixer in 5 separate applications, with 240g sprayed each time, for a total of 1200g, to obtain a mixed wet material.

[0102] Step 6: Feed the mixed wet material into the disc granulator, set the disc granulator inclination angle to 35°, rotation speed to 45 r / min, and feeding speed to 48 kg / h for granulation. After granulation, the wet particles of 2-4 mm are collected by screening through a 2-4 mm screen. Fine particles with a particle size less than 2 mm are directly returned to the mixer, while coarse particles with a particle size greater than 4 mm are crushed by a crusher and then returned to the mixer.

[0103] Step 7: Spread the collected 2-4mm wet particles evenly on the conveyor belt of the belt dryer to a thickness of 4cm, and dry them in stages according to the following parameters:

[0104] The first stage is set at a drying temperature of 35℃ and a wind speed of 1.5m / s, lasting for 30 minutes.

[0105] The second stage is set at a drying temperature of 45℃ and a wind speed of 2.0m / s, lasting for 40 minutes.

[0106] The third stage is set with a drying temperature of 55℃ and a wind speed of 2.5m / s, lasting for 30 minutes.

[0107] After drying, the granules are cooled to about 25°C at room temperature. The cooled granules are then fed into a vibrating screen and graded using a double-layer screen with an upper mesh size of 4mm and a lower mesh size of 2mm. Coarse granules with a diameter greater than 4mm are crushed and returned to the mixer for recycling along with fine granules with a diameter less than 2mm. Qualified granules of 2-4mm are collected, which is the final product, chili root-promoting fertilizer.

[0108] Example 2

[0109] This embodiment adjusts the pH value of the system in step 2 based on embodiment 1, specifically as follows:

[0110] Step 2: Weigh 50g of fermented soybean meal with a protein content of 48% and place it in a reaction vessel. Add 250g of deionized water and 0.25g of neutral protease with an activity of 120,000 U / g. Adjust the pH of the system to 6.5, set the temperature to 50℃ and the stirring speed to 100r / min for 2 hours to obtain a polypeptide solution. Add 50g of zinc sulfate to the polypeptide solution, set the temperature to 35℃ and the stirring speed to 120r / min for 3 hours to obtain a bioactive zinc peptide complex solution for later use.

[0111] The remaining steps are the same as in Example 1.

[0112] Example 3

[0113] This embodiment adjusts the amount of Bacillus subtilis inoculant added in step 3 based on embodiment 1, specifically as follows:

[0114] Step 3: Sterilize the stainless steel fermentation tank at 121℃ for 30 minutes, and simultaneously sterilize 360g of deionized water with ultraviolet light.

[0115] 300g of Bacillus subtilis inoculum with a concentration of 600 million CFU / g and 120g of seaweed extract with an alginate content of 18% were added to a sterilized stainless steel fermenter. 360g of sterilized deionized water was added and stirred until dissolved. The fermentation was carried out at a temperature of 30℃, a rotation speed of 120r / min, and an aeration rate of 0.5vvm for 7 hours to obtain a microbial activated liquid for later use.

[0116] Step 4: Add 4700g of steel slag powder, 1500g of diatomaceous earth, 1000g of 75% humic acid (HA), 800g of potassium sulfate with a potassium content of 52% (calculated as K2O), and 200g of bioactive zinc peptide composite liquid into a mixer. Set the mixer speed to 320r / min and mix for 15min.

[0117] The remaining steps are the same as in Example 1.

[0118] Example 4

[0119] This embodiment adjusts the amount of each component added in step 5 based on embodiment 1, specifically as follows:

[0120] Step 5: Add 350g of sodium lignosulfonate to the mixer, stir at 300r / min for 2min, then add 130g of polyglutamic acid with a molecular weight of 1.5 million, and continue stirring for 8min;

[0121] During the mixing process, deionized water was sprayed into the mixer in 5 separate applications, with 240g sprayed each time, for a total of 1200g, to obtain a mixed wet material.

[0122] The remaining steps are the same as in Example 1.

[0123] Comparative Example 1

[0124] This comparative example adjusts the pretreatment process of steel slag waste based on Example 1, eliminating the removal of metal scraps. Specifically:

[0125] Step 1: Select steel slag waste with SiO2 content of 26% and CaO content of 35%, crush it into coarse powder with a particle size of 5mm using a jaw crusher, and then feed the coarse powder into an air jet mill. Set the crushing pressure to 0.8MPa and the feeding rate to 100kg / h for crushing. After crushing, sieve through a 200-mesh standard sieve and collect the undersize material to obtain steel slag fine powder for later use. Select diatomaceous earth ore with SiO2 content of 88%, crush it into mineral sand with a particle size of 8mm using a jaw crusher, spread the mineral sand evenly on a tray with a thickness of 4cm, put it into an electric heating constant temperature oven, set the drying temperature to 110℃ and the drying time to 2.5h for drying, and then let it cool naturally to room temperature to obtain diatomaceous earth for later use.

[0126] The remaining steps are the same as in Example 1.

[0127] Comparative Example 2

[0128] This comparative example is based on Example 1, except that step 2 is omitted, and in step 4, zinc sulfate is used instead of the bioactive zinc peptide complex solution. Specifically:

[0129] Step 4: Add 4700g of steel slag powder, 1500g of diatomaceous earth, 1000g of 75% humic acid (HA), 800g of potassium sulfate (52% potassium content as K2O), and 22.2g of zinc sulfate into a mixer. Set the mixer speed to 320r / min and mix for 15min.

[0130] The remaining steps are the same as in Example 1.

[0131] Comparative Example 3

[0132] Based on Example 1, this comparative example omits sterilization treatment of the stainless steel fermenter and deionized water in step 3. Specifically:

[0133] Step 3: Add 200g of Bacillus subtilis inoculum with a concentration of 600 million CFU / g and 120g of seaweed extract with a content of 18% alginate to a stainless steel fermenter, add 360g of deionized water and stir until dissolved, set the temperature to 30℃, the rotation speed to 120r / min and the aeration rate to 0.5vvm and ferment for 7h to obtain the microbial activation solution for later use.

[0134] The remaining steps are the same as in Example 1.

[0135] Comparative Example 4

[0136] This comparative example, based on Example 1, adjusts the order of adding the dispersing agent and functional agent in step 5, specifically as follows:

[0137] Step 5: Add 250g of sodium lignosulfonate and 80g of polyglutamic acid with a molecular weight of 1.5 million to the mixer, and stir at 300r / min for 10min.

[0138] During the mixing process, deionized water was sprayed into the mixer in 5 separate applications, with 240g sprayed each time, for a total of 1200g, to obtain a mixed wet material.

[0139] The remaining steps are the same as in Example 1.

[0140] Comparative Example 5

[0141] This comparative example is based on Example 1, but the drying method in step 7 is adjusted as follows:

[0142] Step 7: Spread the collected 2-4mm wet granules evenly on the conveyor belt of the belt dryer to a thickness of 4cm. Set the drying temperature to 45℃ and the air speed to 2.0m / s for 100min. After drying, place the granules in a room temperature environment to cool to about 25℃. Then, send the cooled granules into a vibrating screen and use a double-layer screen with an upper mesh size of 4mm and a lower mesh size of 2mm to classify them. After crushing the coarse granules with a diameter greater than 4mm, return them to the mixer for recycling along with the fine granules with a diameter less than 2mm. Collect the qualified 2-4mm granules, which is the final product, chili root-promoting fertilizer.

[0143] The remaining steps are the same as in Example 1.

[0144] The chili root-promoting fertilizers prepared in the above examples and comparative examples were subjected to appearance and basic performance tests. The appearance morphology of the granules was observed and recorded. The compressive strength of the granules was tested using an electronic universal testing machine, and the wear rate of the granules was tested using a tumbling abrasion tester. The fertilizer granules were also immersed in water to observe the disintegration and dispersion rate of the fertilizer in the water. The statistical results are as follows:

[0145]

[0146] The root-promoting performance of the chili root-promoting fertilizers prepared in the above examples and comparative examples was tested. The operation steps are as follows:

[0147] Mix peat moss, perlite, and vermiculite evenly in a mass ratio of 3:1:1, sterilize at 125℃ for 30 minutes to remove bacteria and weed seeds, and then fill the mixture into seedling trays.

[0148] Select plump, undamaged horn pepper seeds with a germination rate of ≥95%, soak them in 55℃ warm water for 15 minutes, cool them and continue soaking for 6 hours, and then sow them in seedling trays.

[0149] The seedling trays were transferred to an artificial climate chamber and germinated in darkness at 25°C, 70% humidity. When the seedlings had two leaves and one heart, they were transplanted, one seedling per pot. For each example and comparative example, 5g of fertilizer was applied per pot to 2cm below the surface of the substrate. A control group without fertilizer was also set up. All other management conditions for each example, comparative example, and control group were kept the same.

[0150] Maintain 12 hours of light per day, daytime temperature of 28℃, nighttime temperature of 20℃, humidity range of 65% to 70%, and substrate humidity of 60% to 65%. Conduct testing after 45 days.

[0151] Five plants were randomly selected from each group, and their plant height, stem diameter, fresh root weight, and dry root weight were measured and recorded. The average values ​​were calculated. In addition, five plants were randomly selected from each group, and their roots were rinsed with clean water. The roots were then scanned using a root scanner, and the total root length, root surface area, root volume, and number of root tips were analyzed. The average values ​​were calculated.

[0152] The statistical results are as follows:

[0153]

[0154] Analyzing the above data, the following conclusions can be drawn:

[0155] Based on the appearance inspection and basic performance test data, it can be seen that Example 1 and Example 2 only adjusted the pH value of the system. The enzymatic hydrolysis and chelation reactions were stable, so the differences in various indicators were minimal. This indicates that the pH value of the system in the range of 6.0 to 6.5 has no significant impact on the basic performance.

[0156] In Example 3, due to the increased amount of Bacillus subtilis inoculant, the microbial metabolites slightly improved the particle adhesion, resulting in a slightly higher compressive strength than in Examples 1 and 2, and a slightly lower wear rate than in Examples 1 and 2.

[0157] Example 4 optimizes the dosage of dispersant and functional additives, resulting in better dispersibility and particle formability, the highest compressive strength, the lowest wear rate, and the fastest disintegration rate, demonstrating the importance of the synergistic effect of the additives.

[0158] Comparative Example 1 did not remove metal debris from the steel slag. The metal particles affected the particle density, resulting in a decrease in compressive strength, an increase in wear rate, a slower disintegration rate, and the adhesion of metal debris to a certain extent affected the appearance.

[0159] Comparative Example 2 only replaced the nutrient form without changing the particle physical molding process, so the appearance was consistent with Example 1. However, zinc sulfate does not have the binding properties of peptides in bioactive zinc-titanium composite liquid, so the compressive strength is slightly lower than that of Example 1, and the wear rate is slightly increased. In addition, inorganic zinc does not have the function of accelerating the swelling and dispersion of peptides, so the disintegration rate is significantly slower.

[0160] Comparative Example 3 did not sterilize the fermenter and deionized water. As a result, the miscellaneous bacteria competed with Bacillus subtilis for nutrients, leading to insufficient activity of the microbial activation solution, decreased particle adhesion, and inferior compressive strength and wear rate compared to the Example. The disintegration rate was also significantly slower.

[0161] Comparative Example 4 reversed the order of adding dispersant and functional additives. The dispersant was not dispersed in advance as a base material, which led to the agglomeration of functional additives. The particles were unevenly bonded in some areas, resulting in agglomeration. The compressive strength was the lowest, and the wear rate and disintegration rate were the worst.

[0162] Comparative Example 5 used a single-temperature drying method, and the lack of staged heating caused rapid water loss and cracking on the particle surface, resulting in damage to structural integrity and unsatisfactory compressive strength and wear rate.

[0163] The data from the root-promoting performance test show that the difference in pH value between the systems of Example 1 and Example 2 did not affect the enzymatic hydrolysis efficiency and the stability of chelated zinc. Therefore, the difference in root-promoting indicators was small, indicating that the pH value control range in the process was reasonable.

[0164] Example 3 increased the amount of Bacillus subtilis, which increased the secretion of auxin and gibberellin plant hormones, promoting root growth. Therefore, the total root length, number of root tips and other indicators were better than those in other examples, demonstrating the root-promoting effect of beneficial microorganisms.

[0165] Example 4 optimized the dosage of adjuvants. Polyglutamic acid enhanced the chelation and slow-release capacity of nutrients, and sodium lignosulfonate improved the dispersibility of fertilizers. The roots were in more complete contact with nutrients, so the plant height, stem diameter and fresh weight of roots were all optimal, which verified the effect of adjuvants on improving nutrient utilization efficiency.

[0166] In Comparative Example 1, metal debris was not removed. After the chili pepper roots came into contact with the metal impurities, they suffered slight mechanical damage and there was a potential risk of metal contamination, which inhibited root growth. As a result, the fresh weight of the roots and the total length of the roots were significantly reduced compared to Example 1, and the plant height and stem diameter were also affected.

[0167] In Comparative Example 2, inorganic zinc sulfate was used instead of bioactive zinc peptide compound solution. Inorganic zinc is easily fixed by the soil, resulting in low root absorption efficiency. The synthesis of auxin and the regulation of enzyme activity involving zinc are hindered. Therefore, the total root length and root tip number are lower than in Example 1, verifying the advantages of chelated zinc.

[0168] In Comparative Example 3, the lack of sterilization resulted in insufficient activity of Bacillus subtilis, weakening its ability to inhibit pathogens and secrete plant hormones. At the same time, the carbon source utilization efficiency of the seaweed extract decreased, so the root dry weight, root volume and other indicators were worse than those in Example 1, demonstrating the role of sterilization process in ensuring the function of microorganisms.

[0169] Comparative Example 4 showed uneven fertilizer dispersion and nutrient release imbalance due to adjuvant aggregation, resulting in insufficient root absorption. All indicators were the worst among the comparative examples, illustrating the impact of the strictness of the process parameter sequence on the root-promoting effect.

[0170] Comparative Example 5 showed that particle cracking led to nutrient loss, and there was a slight risk of mold growth during storage, resulting in unstable nutrient supply. Therefore, the root index was lower than that of the other examples, verifying the importance of particle structure integrity for fertilizer efficiency.

[0171] In addition, the control group was not fertilized and lacked essential elements such as silicon, calcium, and zinc, as well as beneficial microorganisms and functional additives. Therefore, the plant height, stem diameter, and root-related indicators were all much lower than those of the examples and comparative examples, which directly demonstrates the significant growth-promoting effect of the root-promoting fertilizer for chili peppers.

[0172] Experimental results show that this fertilizer has significant advantages in physical properties, root-promoting effect, and stability, and has good application prospects and promotion value.

[0173] The embodiments described above are not exhaustive and do not limit the invention to only specific embodiments. Clearly, many modifications and variations can be made based on the above description. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A production process for a root-promoting fertilizer for chili peppers, characterized in that, Includes the following steps: Step 1: Select steel slag waste with SiO2 content ≥25% and CaO content ≥30%, and successively crush, air jet mill, screen and magnetic separation to obtain steel slag powder; select diatomite ore with SiO2 content ≥85%, crush, dry and cool to obtain diatomite. Step 2: Using fermented soybean meal with a protein content ≥45% as raw material, deionized water and protease are added for enzymatic hydrolysis to obtain an enzymatic hydrolysate rich in small molecule peptides; then the enzymatic hydrolysate is mixed with zinc sulfate and chelated to obtain a bioactive zinc peptide complex solution. Step 3: Mix Bacillus subtilis inoculant, seaweed extract and sterile deionized water, place in a sterile fermentation tank for fermentation and activation, and obtain microbial activated liquid; Step 4: Add the steel slag powder obtained in Step 1, diatomaceous earth and humic acid, water-soluble potassium and the bioactive zinc peptide composite liquid obtained in Step 2 into a mixer and mix until uniform. Step 5: Add the microbial activation solution obtained in Step 3, sodium lignosulfonate as a dispersing agent, and polyglutamic acid with an average relative molecular mass of 1 million to 2 million as a functional additive to the mixture in Step 4 in sequence. When adding, first add the dispersing agent and stir for a short time to pre-disperse, then add the functional additive and continue stirring. At the same time, spray deionized water to adjust the moisture content of the mixture to 25% to 30% to obtain a functionalized wet mixture. Step 6: Feed the functionalized mixed wet material into a disc granulator for granulation, screen out wet particles with a particle size of 2-4 mm, and return unqualified particles to the mixing process in step 5. Step 7: After spreading the wet granules, dry them using a three-stage gradient temperature drying process; after drying, cool the granules and sieve out qualified granules with a particle size of 2-4mm to obtain the chili root-promoting fertilizer. Unqualified granules are returned to step 5 for recycling.

2. The production process of the chili root-promoting fertilizer according to claim 1, characterized in that, In step 1, a jaw crusher is used for crushing, and the coarse powder particle size after crushing is ≤5mm; The air jet mill is used for pulverization, with a pulverization pressure of 0.8 MPa and a feed rate of 100 kg / h; sieving is performed using a 200-mesh standard sieve. The magnetic separation uses a permanent magnet drum separator, with the magnetic field strength set at 10000~12000Gs and the processing rate at 100kg / h.

3. The production process of the chili root-promoting fertilizer according to claim 1, characterized in that, In step 1, the diatomaceous earth is dried under the following conditions: temperature 100-120℃, time 2-3h, and spreading thickness ≤5cm.

4. The production process of the chili root-promoting fertilizer according to claim 1, characterized in that, In step 2, the mass ratio of fermented soybean meal, deionized water, and protease is 1:4-6:0.003-0.008; The enzymatic hydrolysis conditions were: pH 6.0–6.5, temperature 45–55℃, stirring speed 80–120 r / min, and hydrolysis time 2 h. The mass ratio of fermented soybean meal to zinc sulfate was 1:0.8-1.

2. The chelation reaction conditions were: temperature 30-40℃, stirring speed 100-150 r / min, and chelation time 3h.

5. The production process of the chili root-promoting fertilizer according to claim 1, characterized in that, In step 3, the concentration of Bacillus subtilis in the Bacillus subtilis inoculant is ≥500 million CFU / g, and the content of alginate in the seaweed extract is ≥15%; The mass ratio of Bacillus subtilis inoculum, seaweed extract, and deionized water is 2:1:3; Before fermentation, the stainless steel fermentation tank was sterilized at 121℃ for 30 minutes, and the deionized water was sterilized by ultraviolet light. The fermentation conditions were: temperature 25–35℃, rotation speed 100–150 r / min, aeration rate 0.5 vvm, and fermentation time 6–8 h.

6. The production process of the chili root-promoting fertilizer according to claim 1, characterized in that, In step 4, the humic acid contains HA ≥ 70%, and the water-soluble potassium is one or more of potassium sulfate, potassium chloride, or potassium nitrate, with a potassium content of ≥ 50% as K2O. The mass ratio of steel slag powder, diatomaceous earth, humic acid, water-soluble potassium, and bioactive zinc-titanium composite solution is 30-45:10-18:8-12:5-10:1-3. During mixing, set the mixer speed to 300-350 r / min and the mixing time to 15 min.

7. The production process of the chili root-promoting fertilizer according to claim 1, characterized in that, In step 5, the mass ratio of the added microbial activating liquid, functional additives, dispersing agents and added steel slag powder is 5-7:0.5-1.5:2-4:30-45; When adding, first add the dispersing agent and stir at 300 r / min for 2 minutes, then add the functional agent and continue stirring for 8 minutes.

8. The production process of the chili root-promoting fertilizer according to claim 1, characterized in that, In step 6, the disc granulator is set with an inclination angle of 35°, a rotation speed of 40-50 r / min, and a feeding speed of 45-50 kg / h; During screening, fine particles <2mm are returned directly to the mixer, while coarse particles >4mm are crushed and then returned to the mixer.

9. The production process of the chili root-promoting fertilizer according to claim 1, characterized in that, In step 7, the wet particles are evenly spread on the conveyor belt of the belt dryer, with a thickness of 3-5 cm. The parameters for the staged drying are as follows: the first stage drying temperature is 35℃, the wind speed is 1.5m / s, and the time is 30min; the second stage drying temperature is 45℃, the wind speed is 2.0m / s, and the time is 40min; the third stage drying temperature is 55℃, the wind speed is 2.5m / s, and the time is 30min. The screening process uses a double-layer screen with an upper mesh size of 4mm and a lower mesh size of 2mm. Coarse particles with a diameter >4mm are crushed and then returned to the mixer for recycling along with fine particles with a diameter <2mm.

10. A root-promoting fertilizer for chili peppers, characterized in that, It is prepared by the production process of chili root-promoting fertilizer according to any one of claims 1-9.

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