Soil improvement compound fertilizer based on crop straws and preparation method thereof

Abstract

The invention discloses a soil improvement compound fertilizer based on crop straws. The soil improvement compound fertilizer comprises the following components in parts by weight: 50-60 parts of modified straws, 20-30 parts of decomposed coffee grounds, 12-18 parts of modified bone meal, 8-12 parts of modified plant ash and 4-6 parts of a compound microbial agent. The preparation method comprises the following steps: S1, putting the modified straws, the decomposed coffee grounds, the modified bone meal and the modified plant ash into a double-shaft paddle mixer in proportion, and mixing at the speed of 300r / min for 20 minutes to obtain a mixed solid material; s2, feeding the mixed solid material into a closed inoculation chamber, uniformly spraying a compound microbial agent on the surface of the mixed solid material through a high-pressure atomization nozzle, and obtaining an inoculated material after the compound microbial agent is inoculated; and S3, putting the inoculated material into a rotary drum granulator, setting the rotating speed of a rotary drum to be 20-30r / min, and granulating to obtain the fertilizer. The crop straw-based soil improvement compound fertilizer produced by the invention is high in nutrient content, and can improve the soil quality, promote the growth of crops and increase the yield.

Description

Technical Field

[0001] This invention relates to the field of organic fertilizer preparation technology, and in particular to a soil-improving compound fertilizer based on crop straw and its preparation method. Background Technology

[0002] As a major agricultural country, my country produces a large amount of crop straw every year, which is an important renewable agricultural resource. These straw resources are rich in organic matter and nutrients, and using straw as the main raw material to produce organic fertilizer is an important way to realize its resource utilization. Currently, common straw fertilization technologies mainly rely on traditional composting fermentation, a process that is time-consuming, typically requiring 30-60 days, and often involves incomplete fermentation, failing to thoroughly break down the dense lignocellulose structure of the straw. This results in slow nutrient release and poor physical properties in the final fertilizer, affecting its market value and application effectiveness.

[0003] On the other hand, with the development of intensive agriculture, the long-term excessive application of chemical fertilizers has led to a series of soil problems such as soil compaction, acidification, decline in organic matter, and imbalance of microbial communities. The market demand for compound fertilizers that combine soil improvement and nutrient supply functions is becoming increasingly urgent. Existing soil-improving fertilizers often rely on single components such as humic acid and bentonite, failing to achieve synergistic effects with agricultural waste such as straw. Furthermore, many organic fertilizers have low nutrient content and poor nutrient forms, making them difficult for plants to absorb and utilize, resulting in low fertilizer utilization efficiency.

[0004] Therefore, this application provides a soil-improving compound fertilizer based on crop straw and its preparation method to solve the problems of low fertility of traditional organic fertilizers, which leads to low crop yield and poor growth and development, thereby increasing organic matter content, improving soil quality, promoting crop growth, and increasing crop yield. Summary of the Invention

[0005] The purpose of this invention is to provide a soil-improving compound fertilizer based on crop straw and its preparation method, in order to solve the problems of low fertility of traditional organic fertilizers, which leads to low crop yield and poor growth and development, increase organic matter content, improve soil quality, promote crop growth, and increase crop yield.

[0006] In a first aspect, the present invention provides a soil-improving compound fertilizer based on crop straw, comprising the following components in parts by weight: 50-60 parts modified straw, 20-30 parts decomposed coffee grounds, 12-18 parts modified bone meal, 8-12 parts modified wood ash, and 4-6 parts compound microbial inoculant.

[0007] As a preferred embodiment of the present invention, the modified straw is prepared by the following method: the straw is crushed to a particle size of 1-2 cm using a coarse crusher and the moisture content of the straw is adjusted to 15-20%. The straw is then placed into the sealed cavity of a steam explosion machine, the feed valve is closed, saturated steam is introduced into the cavity, the pressure increase rate is controlled at 0.1 MPa / min, so that the final pressure is stabilized between 1.2-1.5 MPa and the temperature inside the cavity is 180-200℃. After maintaining the final pressure for 30-60 seconds, the pressure relief valve is opened, and the pressure is released within 0.1 seconds. The straw after steam explosion automatically falls into the discharge bin to obtain the modified straw.

[0008] As a preferred technical solution of the present invention, the fermented coffee grounds are prepared by the following method: fresh coffee grounds are washed and placed in a continuous fermentation tank, the temperature inside the fermentation tank is set to 50-60°C and the humidity to 55-65%, the material is turned over every 12 hours, and fermentation is continued for 12-16 days to obtain fermented coffee grounds.

[0009] As a preferred embodiment of the present invention, the modified bone powder is prepared by the following method: first, defatted bone powder and 1% citric acid solution are placed in an acid washing tank at a mass ratio of 1:3, soaked for 4-6 hours, and then rinsed with water 3 times to obtain acid-washed bone powder; then, acid-washed bone powder and 1% sodium bicarbonate solution are placed in an alkaline washing tank at a mass ratio of 1:2, soaked for 1-2 hours to obtain alkaline-washed bone powder; after rinsing the alkaline-washed bone powder with water 3 times, it is placed in a drum dryer and dried at 60°C for 1 hour to obtain modified bone powder.

[0010] As a preferred technical solution of the present invention, the modified wood ash is prepared by the following method: zinc sulfate and borax are weighed and dissolved in water according to the mass ratio of zinc sulfate:borax:water of (1-2):(0.5-1):100 to prepare a trace element mixed solution. Wood ash and trace element mixed solution are placed in a vertical mixer at a mass ratio of 1:3 and stirred at a speed of 60-100 r / min for 60-80 minutes. After stirring, the mixture is allowed to stand for 6 hours and filtered. The filtered wet wood ash is placed in an oven and dried at 60°C for 2 hours to obtain modified wood ash.

[0011] As a preferred embodiment of the present invention, the composite microbial agent is prepared by the following method: Bacillus amyloliquefaciens bacterial solution and Bacillus gelatinosa bacterial solution are injected into a sterile mixing tank at a mass ratio of 1:1 using a metering pump to obtain a mixed bacterial solution; then, sterile water is added to the sterile mixing tank at a mass ratio of 1:10 for the mixed bacterial solution and sterile water, and the mixture is stirred at a speed of 100 r / min for 10 minutes to obtain the composite microbial agent.

[0012] As a preferred embodiment of the present invention, the composite microbial agent is stored at a temperature of 25–30°C.

[0013] Secondly, the present invention also provides a method for preparing a soil-improving compound fertilizer based on crop straw, comprising the following steps: S1. Place the modified straw, decomposed coffee grounds, modified bone meal, and modified wood ash into a twin-shaft paddle mixer in proportion and mix at 300 r / min for 20 minutes to obtain a mixed solid material. S2. The mixed solid material is fed into the sealed inoculation chamber by the conveyor belt. The compound microbial agent is evenly sprayed on the surface of the mixed solid material through the high-pressure atomizing nozzle. The pressure of the high-pressure atomizing nozzle is 0.6MPa and the atomized particle size is 50-100μm. The conveyor belt is equipped with stirring blades to turn the material synchronously. After the compound microbial agent is inoculated, the inoculated material is obtained. S3. Place the inoculum into a rotary drum granulator, set the drum speed to 20-30 r / min, and granulate to obtain a soil-improving compound fertilizer based on crop straw.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention incorporates modified straw into a soil-improving compound fertilizer based on crop straw. The straw is modified using a steam explosion method. Under high temperature and pressure, steam rapidly penetrates the straw fibers. When the pressure is released instantaneously, the originally tight fiber structure of the straw is destroyed, creating numerous pores. This modified straw, when applied to the soil, effectively increases the soil's porosity, allowing air to circulate more easily and improving soil permeability. Crop straw itself is rich in carbon, hydrogen, oxygen, and other elements, making it a high-quality source of organic matter. After steam explosion modification, the straw gradually decomposes in the soil, releasing a large amount of organic matter. This improves the soil's aggregate structure, making it looser and more fertile. The increased organic matter also enhances the soil's water and fertilizer retention capacity, reducing water and nutrient loss.

[0015] 2. This invention incorporates modified bone meal into a soil-improving compound fertilizer based on crop straw, enhancing the availability of phosphorus in the fertilizer and providing slow-release phosphorus nutrition for crops. Through alternating acid-base activation modification of the bone meal, the acidity and chelating ability of citric acid are first utilized to partially dissolve the calcium phosphate in the bone meal, converting it into soluble calcium dihydrogen phosphate. Simultaneously, citrate ions chelate calcium ions, preventing redeposition. Then, treatment with the weak base sodium bicarbonate neutralizes the residual acidity of the bone meal and converts some phosphates into a form more easily absorbed by plant roots. This also adjusts the pH of the raw materials, preventing stress on microorganisms added during subsequent preparation. The modified bone meal can efficiently convert inert phosphorus in the fertilizer into available phosphorus that can be absorbed by plants. The portion not completely converted can still serve as a slow-release phosphorus pool, meeting the phosphorus requirements of crops in the later stages of growth.

[0016] 3. This invention, in a soil-improving compound fertilizer based on crop straw, incorporates modified wood ash, which not only provides abundant potassium but also enriches the micronutrient content. By loading micronutrients onto the wood ash, the hydroxyl and carboxyl groups on the surface of the wood ash form coordination bonds with zinc and boron ions, stably adsorbing the micronutrients onto the surface of the wood ash and achieving multifunctional fertilizer nutrients. Micronutrients play a crucial regulatory role in crop growth and development; for example, zinc participates in auxin synthesis, and boron promotes pollen germination and pollen tube growth. This micronutrient loading modification of wood ash transforms ordinary wood ash from a single potassium fertilizer into a compound mineral-source fertilizer that integrates potassium, zinc, and boron supply.

[0017] 4. This invention incorporates a compound microbial agent into a soil-improving compound fertilizer based on crop straw. Two beneficial microorganisms, *Bacillus amyloliquefaciens* and *Bacillus mucilaginosus*, are selected to create this compound microbial agent, increasing soil organic matter content and improving soil structure. *Bacillus amyloliquefaciens* can secrete various enzymes such as amylase and protease to decompose organic matter in the soil; *Bacillus mucilaginosus* has phosphorus and potassium solubilizing functions, converting insoluble phosphorus and potassium in the soil into forms that crops can absorb and utilize. After the compound fertilizer made from this compound microbial agent is applied to the soil, the beneficial microorganisms rapidly multiply under suitable environmental conditions, forming a dominant microbial community. These microorganisms, through their metabolic activities, secrete organic acids, hormones, and other substances, regulating the soil's microecological environment, reducing the occurrence of crop diseases and pests, and ensuring the healthy growth of crops. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method for preparing soil-improving compound fertilizer based on crop straw according to the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, a method for preparing a soil-improving compound fertilizer based on crop straw includes the following steps: S1. Place the modified straw, decomposed coffee grounds, modified bone meal, and modified wood ash into a twin-shaft paddle mixer in proportion and mix at 300 r / min for 20 minutes to obtain a mixed solid material. S2. The mixed solid material is fed into a closed inoculation chamber, and the compound microbial agent is evenly sprayed onto the surface of the mixed solid material through a high-pressure atomizing nozzle. After the compound microbial agent inoculation is completed, the inoculation material is obtained. S3. Place the inoculum into a rotary drum granulator, set the drum speed to 20-30 r / min, and granulate to obtain a soil-improving compound fertilizer based on crop straw.

[0023] All raw materials used in this invention are commercially available.

[0024] Example 1

[0025] A soil-improving compound fertilizer based on crop straw comprises the following components in parts by weight: 50 parts modified straw, 20 parts decomposed coffee grounds, 12 parts modified bone meal, 8 parts modified wood ash, and 4 parts compound microbial inoculant.

[0026] Modified straw is prepared by the following method: The straw is crushed to a particle size of 1-2 cm using a coarse crusher and the moisture content of the straw is adjusted to 15%. The straw is then placed into the sealed cavity of a steam explosion machine, the feed valve is closed, and saturated steam is introduced into the cavity. The pressure increase rate is controlled at 0.1 MPa / min, so that the final pressure is stabilized at 1.2 MPa and the temperature inside the cavity is 180℃. After maintaining the final pressure for 60 seconds, the pressure relief valve is opened, and the pressure is released within 0.1 seconds. The straw after steam explosion automatically falls into the discharge bin to obtain modified straw.

[0027] The fermented coffee grounds are prepared by the following method: fresh coffee grounds are washed and placed in a continuous fermentation tank. The temperature inside the fermentation tank is set to 60°C and the humidity to 65%. The grounds are turned over every 12 hours and fermented for 12 days to obtain fermented coffee grounds.

[0028] Modified bone meal was prepared by the following method: First, defatted bone meal and 1% citric acid solution were placed in an acid pickling tank at a mass ratio of 1:3 and soaked for 4 hours. Then, the mixture was rinsed with water 3 times to obtain acid-washed bone meal. Next, acid-washed bone meal and 1% sodium bicarbonate solution were placed in an alkaline washing tank at a mass ratio of 1:2 and soaked for 1 hour to obtain alkaline-washed bone meal. After rinsing the alkaline-washed bone meal 3 times with water, the mixture was placed in a drum dryer and dried at 60°C for 1 hour to obtain modified bone meal.

[0029] Modified wood ash was prepared by the following method: Zinc sulfate and borax were weighed and dissolved in water at a mass ratio of zinc sulfate:borax:water of 1:0.5:100 to prepare a trace element mixed solution. Wood ash and trace element mixed solution were placed in a vertical mixer at a mass ratio of 1:3 and stirred at 60 r / min for 80 minutes. After stirring, the mixture was allowed to stand for 6 hours and filtered. The filtered wet wood ash was placed in an oven and dried at 60℃ for 2 hours to obtain modified wood ash.

[0030] The compound microbial agent was prepared by the following method: Bacillus amyloliquefaciens bacterial solution and Bacillus colloidis bacterial solution were injected into a sterile mixing tank at a mass ratio of 1:1 using a metering pump to obtain a mixed bacterial solution; then, sterile water was added to the sterile mixing tank at a mass ratio of 1:10 of the mixed bacterial solution to sterile water, and the mixture was stirred at a speed of 100 r / min for 10 minutes to obtain the compound microbial agent; the obtained compound microbial agent was stored at a temperature of 25-30℃.

[0031] A method for preparing a soil-improving compound fertilizer based on crop straw includes the following steps: S1. Place the modified straw, decomposed coffee grounds, modified bone meal, and modified wood ash into a twin-shaft paddle mixer in proportion and mix at 300 r / min for 20 minutes to obtain a mixed solid material. S2. The mixed solid material is fed into the sealed inoculation chamber by the conveyor belt. The compound microbial agent is evenly sprayed on the surface of the mixed solid material through the high-pressure atomizing nozzle. The pressure of the high-pressure atomizing nozzle is 0.6MPa and the atomized particle size is 50-100μm. The conveyor belt is equipped with stirring blades to turn the material synchronously. After the compound microbial agent is inoculated, the inoculated material is obtained. S3. Place the inoculum into a rotary drum granulator, set the drum speed to 20 r / min, and granulate to obtain a soil-improving compound fertilizer based on crop straw.

[0032] Example 2

[0033] A soil-improving compound fertilizer based on crop straw comprises the following components in parts by weight: 55 parts modified straw, 25 parts decomposed coffee grounds, 15 parts modified bone meal, 10 parts modified wood ash, and 5 parts compound microbial inoculant.

[0034] Modified straw is prepared by the following method: The straw is crushed to a particle size of 1-2 cm using a coarse crusher and the moisture content of the straw is adjusted to 18%. The straw is then placed into the sealed cavity of a steam explosion machine, the feed valve is closed, and saturated steam is introduced into the cavity. The pressure increase rate is controlled at 0.1 MPa / min, so that the final pressure is stabilized at 1.3 MPa and the temperature inside the cavity is 190℃. After maintaining the final pressure for 45 seconds, the pressure relief valve is opened, and the pressure is released within 0.1 seconds. The straw after steam explosion automatically falls into the discharge bin to obtain modified straw.

[0035] The fermented coffee grounds are prepared by the following method: fresh coffee grounds are washed and placed in a continuous fermentation tank. The temperature inside the fermentation tank is set at 55°C and the humidity at 60%. The grounds are turned over every 12 hours and fermented for 14 days to obtain fermented coffee grounds.

[0036] Modified bone meal was prepared by the following method: First, defatted bone meal and 1% citric acid solution were placed in an acid pickling tank at a mass ratio of 1:3 and soaked for 5 hours. Then, the mixture was rinsed with water 3 times to obtain acid-washed bone meal. Next, acid-washed bone meal and 1% sodium bicarbonate solution were placed in an alkaline washing tank at a mass ratio of 1:2 and soaked for 1.5 hours to obtain alkaline-washed bone meal. After rinsing the alkaline-washed bone meal 3 times with water, the mixture was placed in a drum dryer and dried at 60°C for 1 hour to obtain modified bone meal.

[0037] Modified wood ash was prepared by the following method: Zinc sulfate and borax were weighed and dissolved in water according to the mass ratio of zinc sulfate:borax:water of 1.5:0.8:100 to prepare a trace element mixed solution. Wood ash and trace element mixed solution were placed in a vertical mixer at a mass ratio of 1:3 and stirred at 80 r / min for 70 minutes. After stirring, the mixture was allowed to stand for 6 hours and filtered. The filtered wet wood ash was placed in an oven and dried at 60℃ for 2 hours to obtain modified wood ash.

[0038] The compound microbial agent was prepared by the following method: Bacillus amyloliquefaciens bacterial solution and Bacillus colloidis bacterial solution were injected into a sterile mixing tank at a mass ratio of 1:1 using a metering pump to obtain a mixed bacterial solution; then, sterile water was added to the sterile mixing tank at a mass ratio of 1:10 of the mixed bacterial solution to sterile water, and the mixture was stirred at a speed of 100 r / min for 10 minutes to obtain the compound microbial agent; the obtained compound microbial agent was stored at a temperature of 25-30℃.

[0039] A method for preparing a soil-improving compound fertilizer based on crop straw includes the following steps: S1. Place the modified straw, decomposed coffee grounds, modified bone meal, and modified wood ash into a twin-shaft paddle mixer in proportion and mix at 300 r / min for 20 minutes to obtain a mixed solid material. S2. The mixed solid material is fed into the sealed inoculation chamber by the conveyor belt. The compound microbial agent is evenly sprayed on the surface of the mixed solid material through the high-pressure atomizing nozzle. The pressure of the high-pressure atomizing nozzle is 0.6MPa and the atomized particle size is 50-100μm. The conveyor belt is equipped with stirring blades to turn the material synchronously. After the compound microbial agent is inoculated, the inoculated material is obtained. S3. Place the inoculum into a rotary drum granulator, set the drum speed to 25 r / min, and granulate to obtain a soil-improving compound fertilizer based on crop straw.

[0040] Example 3

[0041] A soil-improving compound fertilizer based on crop straw comprises the following components in parts by weight: 60 parts modified straw, 30 parts decomposed coffee grounds, 18 parts modified bone meal, 12 parts modified wood ash, and 6 parts compound microbial inoculant.

[0042] Modified straw is prepared by the following method: The straw is crushed to a particle size of 1-2 cm using a coarse crusher and the moisture content of the straw is adjusted to 20%. The straw is then placed into the sealed cavity of a steam explosion machine, the feed valve is closed, and saturated steam is introduced into the cavity. The pressure increase rate is controlled at 0.1 MPa / min, so that the final pressure is stabilized at 1.5 MPa and the temperature inside the cavity is 200℃. After maintaining the final pressure for 30 seconds, the pressure relief valve is opened, and the pressure is released within 0.1 seconds. The straw after steam explosion automatically falls into the discharge bin to obtain modified straw.

[0043] The fermented coffee grounds are prepared by the following method: fresh coffee grounds are washed and placed in a continuous fermentation tank. The temperature inside the fermentation tank is set at 50°C and the humidity at 55%. The grounds are turned over every 12 hours and fermented for 16 days to obtain fermented coffee grounds.

[0044] Modified bone meal was prepared by the following method: First, defatted bone meal and 1% citric acid solution were placed in an acid pickling tank at a mass ratio of 1:3 and soaked for 6 hours. Then, the mixture was rinsed with water 3 times to obtain acid-washed bone meal. Next, acid-washed bone meal and 1% sodium bicarbonate solution were placed in an alkaline washing tank at a mass ratio of 1:2 and soaked for 2 hours to obtain alkaline-washed bone meal. After rinsing the alkaline-washed bone meal 3 times with water, the mixture was placed in a drum dryer and dried at 60°C for 1 hour to obtain modified bone meal.

[0045] Modified wood ash was prepared by the following method: Zinc sulfate and borax were weighed and dissolved in water at a mass ratio of 2:1:100 to prepare a trace element mixed solution. Wood ash and trace element mixed solution were placed in a vertical mixer at a mass ratio of 1:3 and stirred at 100 r / min for 60 minutes. After stirring, the mixture was allowed to stand for 6 hours and filtered. The filtered wet wood ash was placed in an oven and dried at 60℃ for 2 hours to obtain modified wood ash.

[0046] The compound microbial agent was prepared by the following method: Bacillus amyloliquefaciens bacterial solution and Bacillus colloidis bacterial solution were injected into a sterile mixing tank at a mass ratio of 1:1 using a metering pump to obtain a mixed bacterial solution; then, sterile water was added to the sterile mixing tank at a mass ratio of 1:10 of the mixed bacterial solution to sterile water, and the mixture was stirred at a speed of 100 r / min for 10 minutes to obtain the compound microbial agent; the obtained compound microbial agent was stored at a temperature of 25-30℃.

[0047] A method for preparing a soil-improving compound fertilizer based on crop straw includes the following steps: S1. Place the modified straw, decomposed coffee grounds, modified bone meal, and modified wood ash into a twin-shaft paddle mixer in proportion and mix at 300 r / min for 20 minutes to obtain a mixed solid material. S2. The mixed solid material is fed into the sealed inoculation chamber by the conveyor belt. The compound microbial agent is evenly sprayed on the surface of the mixed solid material through the high-pressure atomizing nozzle. The pressure of the high-pressure atomizing nozzle is 0.6MPa and the atomized particle size is 50-100μm. The conveyor belt is equipped with stirring blades to turn the material synchronously. After the compound microbial agent is inoculated, the inoculated material is obtained. S3. Place the inoculum into a rotary drum granulator, set the drum speed to 30 r / min, and granulate to obtain a soil-improving compound fertilizer based on crop straw.

[0048] Comparative Example 1: The difference from Example 1 is that the straw was added directly without modification.

[0049] Comparative Example 2: The difference from Example 1 is that bone meal is added directly without modification.

[0050] Comparative Example 3: The difference from Example 1 is that the wood ash was added directly without modification.

[0051] The soil-improving compound fertilizers based on crop straw produced in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 were tested.

[0052] The soil-improving compound fertilizers based on crop straw produced in Examples 1, 2, and 3, and Comparative Examples 1, 2, and 3 were tested. The total nitrogen content in the fertilizers was determined using GB / T 8572-2010 "Determination of Total Nitrogen Content in Compound Fertilizers - Distillation Titration Method", the available phosphorus content was determined using GB / T 8573-2017 "Determination of Available Phosphorus Content in Compound Fertilizers", the potassium content was determined using GB / T 8574-2010 "Determination of Potassium Content in Compound Fertilizers - Potassium Tetraphenylborate Gravimetric Method", and the organic matter content was determined using NY / T 525-2021 "Organic Fertilizers". The results are shown in Table 1.

[0053] Table 1: Nitrogen, Phosphorus, Potassium, and Organic Matter Contents in Soil Improvement Compound Fertilizers Based on Crop Straw

[0054] As shown in Table 1, the soil improvement compound fertilizers based on crop straw produced in Examples 1, 2, and 3 have higher nitrogen, phosphorus, potassium, and organic matter content, while the soil improvement compound fertilizers based on crop straw produced in Comparative Examples 1, 2, and 3 have lower nitrogen, phosphorus, potassium, and organic matter content.

[0055] Seven days before transplanting cucumbers, soil-improving compound fertilizers based on crop straw produced in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 were applied as base fertilizer for cucumbers and then plowed into the soil. The amount of fertilizer applied was 240 kg per mu. Three parallel experiments were conducted for each example and comparative example, with one mu of land selected for each parallel experiment. The length and yield of cucumbers after harvest were measured.

[0056] Table 2: Cucumber Length and Yield

[0057] As shown in Table 2, when cucumbers were fertilized with the crop straw-based soil-improving compound fertilizers produced in Examples 1, 2, and 3, the cucumbers were longer and the yield per acre was higher. When cucumbers were fertilized with the crop straw-based soil-improving compound fertilizers produced in Comparative Examples 1, 2, and 3, the cucumbers were shorter and the yield per acre was lower.

[0058] In summary, the soil-improving compound fertilizer based on crop straw produced by this invention can solve the problems of low fertility of traditional organic fertilizers, which lead to low crop yields and poor growth and development. The increased organic matter content can improve soil quality, promote crop growth, and thus increase yield.

[0059] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A crop straw based soil improving compound fertilizer, characterized in that, The components include the following weight parts: modified straw 50-60 parts, mature coffee residue 20-30 parts, modified bone meal 12-18 parts, modified wood ash 8-12 parts, and compound microbial agent 4-6 parts.

2. The crop residue based soil improving compound fertilizer as claimed in claim 1, wherein, The modified straw is prepared by the following method: the straw is crushed to a particle size of 1-2 centimeters using a coarse crusher and the water content of the straw is adjusted to 15-20%, then the straw is placed in a sealed cavity of a steam explosion machine, the feed valve is closed, saturated steam is introduced into the cavity, the pressure increase speed is controlled to be 0.1 MPa / min, the final pressure is stabilized between 1.2-1.5 MPa, the temperature in the cavity is 180-200℃, after maintaining the final pressure for 30-60 seconds, the pressure relief valve is opened, the pressure relief is completed within 0.1 second, the straw after steam explosion is automatically dropped into a discharge bin, and the modified straw is obtained.

3. The crop residue based soil improving compound fertilizer as claimed in claim 1, wherein, The mature coffee residue is prepared by the following method: the fresh coffee residue is washed and then placed in a continuous fermentation tank, the temperature in the fermentation tank is set to be 50-60℃, the humidity is set to be 55-65%, the material is stirred every 12 hours, and the fermentation is continuously carried out for 12-16 days, and the mature coffee residue is obtained.

4. The crop residue based soil improving compound fertilizer as claimed in claim 1, wherein, The modified bone meal is prepared by the following method: the defatted bone meal and 1% citric acid solution are placed in an acid washing tank according to a mass ratio of 1:3, the bone meal is soaked for 4-6 hours, then washed with water for 3 times, and the acid washed bone meal is obtained; the acid washed bone meal and 1% sodium bicarbonate solution are placed in an alkali washing tank according to a mass ratio of 1:2, the bone meal is soaked for 1-2 hours, and the alkali washed bone meal is obtained; the alkali washed bone meal is washed with water for 3 times and then placed in a drum dryer, and the bone meal is dried at 60℃ for 1 hour, and the modified bone meal is obtained.

5. The crop residue based soil improving compound fertilizer as claimed in claim 1, wherein, The modified wood ash is prepared by the following method: zinc sulfate and borax are weighed according to a mass ratio of (1-2):(0.5-1):100, dissolved in water to prepare a trace element mixed solution, the wood ash and the trace element mixed solution are placed in a vertical stirrer according to a mass ratio of 1:3, stirred at a speed of 60-100 r / min for 60-80 minutes, and then left to stand for 6 hours and filtered, the filtered wet wood ash is placed in an oven and dried at 60℃ for 2 hours, and the modified wood ash is obtained.

6. The crop residue based soil improving compound fertilizer as claimed in claim 1, wherein, The compound microbial agent is prepared by the following method: bacillus amyloliquefaciens and bacillus mycoides are injected into a sterile mixing tank through a metering pump according to a mass ratio of 1:1 to obtain a mixed bacterial solution; sterile water is added to the sterile mixing tank according to a mass ratio of 1:10 to obtain the compound microbial agent.

7. The crop residue based soil improving compound fertilizer as claimed in claim 6, wherein, The compound microbial agent is stored at a temperature of 25-30℃.

8. A preparation method of a soil improvement compound fertilizer based on crop straw, comprising the following steps: S1, the modified straw, the mature coffee residue, the modified bone meal, and the modified wood ash are placed in a double-shaft paddle mixer according to a proportion, mixed at a speed of 300 r / min for 20 minutes, and a mixed solid material is obtained; S2, the mixed solid material is sent into a closed inoculation chamber by a conveying belt, and the composite microbial inoculant is uniformly sprayed on the surface of the mixed solid material through a high-pressure atomizing nozzle, the pressure of the high-pressure atomizing nozzle is 0.6 MPa, the atomizing particle size is 50-100 μm, a stirring blade is arranged below the conveying belt to synchronously stir and turn the material, and the inoculated material is obtained after the inoculation of the composite microbial inoculant is completed; S3, the inoculated material is placed into a rotary drum granulator, the rotary drum is set to rotate at a speed of 20-30 r / min, and the soil improvement compound fertilizer based on crop straw is prepared by granulation.

Images