Biological organic fertilizer for improving alkaline soil, preparation method and application thereof in orange orchard

Abstract

This invention discloses a bio-organic fertilizer suitable for improving alkaline soil, its preparation method, and its application in citrus orchards, belonging to the field of agricultural soil improvement technology. The organic fertilizer is made from 40.00%-50.00% citrus peel residue, 20.00%-30.00% a mixture of sawdust and straw powder, 15.00%-20.00% a mixture of rapeseed meal and soybean meal, 20.00%-30.00% a mixture of livestock and poultry manure, and 0.25%-0.50% ferrous sulfate. Its preparation includes raw material pretreatment, citrus biogas slurry preparation, mixed fermentation, and finished product preparation. During soil improvement, the dosage is determined according to the soil pH value, and it is applied twice using trenching or hole application methods. This invention realizes the resource utilization of agricultural waste, can efficiently improve alkaline soil, solve the problem of iron deficiency and chlorosis in citrus, and is environmentally friendly and easy to operate, suitable for soil improvement in various types of citrus orchards, especially mountainous citrus orchards.

Description

Technical Field

[0001] This invention relates to the fields of agricultural soil improvement, organic waste fertilization, and fertilizer preparation and utilization, and particularly to bio-organic fertilizers suitable for improving alkaline soils, their preparation methods, and their applications. Background Technology

[0002] In my country's main citrus-producing areas, nearly 15% of the soil in citrus orchards is alkaline. Alkaline soil can lead to a significant reduction in the availability of elements such as iron and zinc, causing iron deficiency chlorosis and zinc deficiency little leaf disease in citrus trees. In severe cases, this can result in reduced citrus production or even crop failure, thus hindering the sustainable development of the citrus industry.

[0003] Currently, methods for improving alkaline soils are mainly divided into two categories: chemical improvement and organic fertilizer improvement. Chemical improvement often involves the direct application of chemical agents such as ferrous sulfate and sulfur powder. Although these can lower the soil pH in the short term, long-term use can easily lead to soil compaction and salt accumulation, and cannot improve the soil organic matter content, while also posing a risk of secondary pollution. Traditional organic fertilizer improvement often uses single-ingredient fermented animal manure or straw fertilizers. These fertilizers are not very targeted, have a long improvement cycle for alkaline soils, and cannot simultaneously solve the iron deficiency problem in citrus trees.

[0004] By searching existing technologies, Chinese invention patent CN121202637A discloses an organic fertilizer for improving the quality of rice under saline-alkali stress and its preparation method. It constructs a system of "chicken manure-rice straw-thermally modified attapulgite-composite microbial agent", which solves the problems of long composting cycle, incomplete improvement of saline-alkali land and insufficient crop resistance in traditional technologies. Chinese invention patent CN113214035A discloses a fertilizer for improving alkaline soil and its preparation method. The raw materials for the product include water-absorbing resin, fermented camellia seed meal, polyallylamine, carboxymethyl cellulose, and SBR emulsion. The fermented camellia seed meal is obtained by fermenting camellia seed meal with Aspergillus niger. Chinese invention patent CN108191582A discloses an alkaline soil organic fertilizer and its manufacturing process. The raw materials of the product include urea, ammonium sulfate, potassium dihydrogen phosphate, phosphate rock powder, natural potassium magnesium sulfate fertilizer, decomposed compost, and distiller's grains. It can not only supplement a variety of nutrients, but also help reduce the soil solution concentration, alleviate the damage caused by the application of chemical fertilizers, and improve the pH and the deficiency of a variety of nutrients. Chinese invention patent CN118479944A discloses an organic fertilizer suitable for alkaline soil and its preparation method. The raw materials include kitchen waste, straw fragments, modified zeolite powder, fermentation agents, etc. The product can provide organic matter for alkaline soil and improve soil heavy metal pollution through the synergistic effect between raw material components. Chinese invention patent CN121135539A discloses an alfalfa-specific organic compound fertilizer, its preparation method and application. It mainly improves alfalfa yield by adding sodium humate-algae complex and modified phosphorus and potassium ore powder loaded with suitable microbial agents. Chinese invention patent CN108164355A discloses a potato-specific alkaline organic bio-fertilizer and its preparation method. Targeting the soil characteristics required for potato cultivation, it adds alkaline regulators and microbial residue, along with well-rotted farmyard manure, nitrogen fertilizer, phosphorus fertilizer, potassium fertilizer, and distiller's grains. This not only improves the nutrient content of the fertilizer itself, but also improves soil looseness and nutrient content, increases fertilizer utilization, reduces costs, and enhances potato quality and yield.

[0005] However, the characteristics of existing technologies are as follows: first, they widely utilize organic waste; second, they add appropriate amounts of chemical fertilizers; third, they emphasize the role of microbial agents; and fourth, they are specifically designed for specific crops. But overall, they rarely consider the addition of micronutrient fertilizers or the formulation of multiple organic wastes, and most lack field trial verification and explanations of actual application effects.

[0006] In particular, the citrus fruit processing industry generates a large amount of fruit peel and pulp. Agricultural production and agricultural product processing also produce various wastes such as sawdust, straw powder, vegetable waste powder, soybean meal powder, and livestock and poultry manure. If these wastes are disposed of indiscriminately, they will not only waste resources but also cause environmental pollution. Therefore, developing a technical solution and fertilizer product that can utilize agricultural waste in a resource-efficient manner, improve alkaline soil and provide nutrients, and especially address the problems of nutrient deficiency and yellowing of citrus fruits caused by alkaline soil in citrus orchards, has become an urgent technical challenge for the high-quality development of the citrus industry, agricultural and rural environmental governance, and ecological construction in some citrus-producing areas. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a bio-organic fertilizer suitable for improving alkaline soils, its preparation method, and its application in citrus orchards. This method utilizes agricultural waste from citrus and other industries to prepare a specialized bio-organic fertilizer, achieving both harmless and resource-based treatment of the waste, efficiently improving alkaline soils in citrus orchards, correcting iron and zinc deficiencies in citrus, and solving problems of low yield and poor quality. Furthermore, it boasts advantages such as environmental friendliness, ease of operation, and strong versatility.

[0008] The present invention adopts the following technical solution: A bio-organic fertilizer suitable for improving alkaline soils, by weight percentage, is composed of the following raw materials: 40.00%-50.00% citrus peel residue, 20.00%-30.00% a mixture of sawdust and straw powder, 15.00%-20.00% a mixture of rapeseed meal powder and soybean meal powder, 20.00%-30.00% a mixture of chicken manure, cow manure and sheep manure, and 0.25%-0.50% ferrous sulfate.

[0009] As a further embodiment of the present invention, the mixing ratio of sawdust powder to straw powder is 1:1-2:1; the mixing ratio of rapeseed meal powder to soybean meal powder is 1:1-2:1; and the mixing ratio of chicken manure, cow manure and sheep manure is 1:1:1-2:1:1.

[0010] The preparation method includes the following steps: Step A: Raw material pretreatment: Crush citrus peel residue, sawdust, straw powder, vegetable residue powder, and soybean meal powder to a particle size of 0.5-1cm. Dry chicken manure, cow manure, and sheep manure to a moisture content of 40%-50% and remove impurities. Step B: Preparation of citrus biogas slurry. Either Option 1 or Option 2 can be used. Option 1 involves inoculating citrus peel residue with compound biological agents and anaerobic fermentation for 15-20 days to obtain biogas slurry. Option 2 involves mixing citrus peel residue with compound biological agents and other organic raw materials and anaerobic fermentation for 15-20 days. Step C: Mixed fermentation. Adjust the moisture content of the material obtained in step B to 50%-55%, inoculate with compound biological agents, and ferment aerobically for 20-25 days, turning it over every 3-5 days. Step D: Finished product preparation. The fermented material is dried until the moisture content is less than 30%, then ferrous sulfate is added and mixed evenly to obtain powdered or granular organic fertilizer.

[0011] As a further aspect of the present invention, the compound biological agent is composed of Bacillus subtilis, yeast and lactic acid bacteria in a ratio of 1:1:1. The amount added in step B is 0.1%-0.3% of the weight of citrus peel residue, and the amount added in step C is 0.05%-0.1% of the total material weight.

[0012] A method for improving alkaline soil in an orange orchard using the aforementioned bio-organic fertilizer includes the following: (1) Dosage: Apply 1000-1500 kg per mu to citrus orchards with pH value of 6.5-7.5, and apply 1500-2000 kg per mu to citrus orchards with pH value of 7.5-8.0; (2) Application time: Apply twice. The first application is before spring budding or before and after fruit harvest, accounting for 60%-70% of the total amount. The second application is from the end of June to the beginning of July, accounting for 30%-40% of the total amount. (3) Application method: Apply by trenching or hole application. Dig trenches / holes around the drip line of the fruit trees, mix the organic fertilizer with the topsoil, backfill and cover with new soil.

[0013] As a further embodiment of the present invention, the trench is 30-40cm deep and 15-20cm wide, and the hole is 30-40cm deep and 20-30cm in diameter.

[0014] The present invention achieves the following technical effects compared to the prior art: The fertilizer raw materials in this invention are all agricultural production and agricultural product processing waste such as citrus, realizing the resource reuse of solid waste, which not only reduces the cost of fertilizer production, but also eliminates the environmental pollution risks of agricultural waste.

[0015] In this invention, the composting of organic materials, combined with ferrous sulfate and biological agents, can not only reduce the soil pH and improve soil alkalinity, but also increase the soil organic matter content, improve soil aggregate structure, and increase the content of nutrients such as available iron in the soil. This plays a role in improving alkaline soil, enriching soil fertility, correcting iron deficiency chlorosis in citrus, and improving yield and quality. Soil improvement and fertilization are completed simultaneously with increased yield and quality.

[0016] This invention uses agricultural organic materials throughout the entire process, combined with biological agents for fermentation, leaving no chemical additives and preventing soil compaction and secondary pollution. It meets the technical requirements of green agriculture and organic citrus cultivation.

[0017] The fertilizer preparation process of this invention is simple and does not require high-end production equipment; the application method is consistent with conventional orchard fertilization operations, which is easy for fruit farmers to master and is suitable for citrus orchards of different sizes, especially suitable for promotion in mountainous alkaline soil citrus orchards. Attached Figure Description

[0018] Figure 1 This is a flowchart of the preparation method of the bio-organic fertilizer suitable for improving alkaline soil in this 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] Example 1 (Amendment of Slightly Alkaline Soil) The fertilizer preparation, by weight percentage, consists of 40.7% citrus peel residue, 20% a mixture of sawdust and straw powder (1:1), 16% a mixture of rapeseed meal powder and soybean meal powder (1:1), 23% a mixture of chicken manure and cow manure (1:1), and 0.3% ferrous sulfate. Scheme 1 was used to prepare the citrus biogas slurry: Citrus peel residue was crushed and inoculated with a compound microbial agent at 0.2%, then anaerobically fermented at 28℃ for 18 days to obtain biogas slurry; the biogas slurry was mixed with the remaining raw materials, inoculated with a compound microbial agent at 0.08%, and the moisture content was adjusted to 52%, then aerobically fermented at 28℃ for 22 days (turning over every 4 days); after fermentation, it was dried until the moisture content was below 30%, then ferrous sulfate was added and mixed thoroughly to obtain powdered organic fertilizer.

[0021] For use in mountainous citrus orchards with a pH of 7.2, apply 1000 kg of the above fertilizer per acre. Apply 700 kg (70%) before bud break in spring and 300 kg (30%) at the end of June, using a circular trench application method (25 cm deep and 18 cm wide). After one growing season, the soil pH decreased to 6.8, the organic matter content increased by 0.6 percentage points, the proportion of yellowed leaves on citrus trees decreased from 32% to 4%, and the yield per acre increased by 20%.

[0022] Example 2 (Amendment of moderately alkaline soil) The fertilizer preparation, by weight percentage, consists of 40.5% citrus peel residue, 20% a mixture of sawdust and straw powder (2:1), 16% a mixture of rapeseed meal powder and soybean meal powder (2:1), 23% a mixture of chicken manure, cow manure, and sheep manure (2:1:1), and 0.5% ferrous sulfate. Alternatively, Scheme Two is used: the citrus peel residue is mixed with all organic materials and 0.3% compound microbial agent, and anaerobic fermented for 18 days at 58% moisture content, followed by aerobic fermentation for 25 days (turning over every 3 days). After drying until the moisture content is less than 30%, ferrous sulfate is added to obtain granular organic fertilizer.

[0023] This fertilizer was applied to citrus orchards with a pH of 7.8, at a rate of 2000 kg per acre. 1200 kg (60%) was applied after harvest, and 800 kg (40%) was applied in early July, using hole application (30 cm deep, 25 cm in diameter). After one growing season, the soil pH dropped to 7.0, the available iron content increased by 1.2 mg / kg, citrus yellowing was completely eliminated, and yield increased by 26%.

[0024] To further verify the application effect of the organic fertilizer of the present invention, four additional examples with different raw material ratios, preparation schemes and application scenarios are provided below. The improvement effects have all been verified by field trials.

[0025] Example 3 (Slightly alkaline soil + low ferrous sulfate ratio) The fertilizer preparation, by weight percentage, consisted of 40.75% citrus peel residue, 20% a mixture of sawdust and straw powder (1:2), 16% a mixture of rapeseed meal powder and soybean meal powder (1:2), 23% a mixture of chicken manure and sheep manure (1:1), and 0.25% ferrous sulfate. A separate biogas production scheme was used to prepare citrus biogas slurry: the pretreated citrus peel residue was inoculated with 0.1% of a compound biological agent (Bacillus subtilis: yeast: lactic acid bacteria = 1:1:1), the moisture content was adjusted to 55%, and anaerobic fermentation was carried out at 25℃ for 20 days to obtain biogas slurry; the biogas slurry was mixed with the remaining pretreated raw materials, inoculated with 0.05% of the compound biological agent, the moisture content was adjusted to 50%, and aerobic fermentation was carried out at 25℃ for 25 days, turning the mixture every 5 days; after fermentation, the mixture was dried to a moisture content of 25%, ferrous sulfate was added and mixed evenly to obtain powdered organic fertilizer.

[0026] For soil improvement applications in slightly alkaline citrus orchards with a pH of 7.5, apply 1000 kg of this organic fertilizer per acre. Apply 600 kg (60%) after harvest and 400 kg (40%) in early July, using a radial trench application method, with trenches 20 cm deep and 15 cm wide. After one growing season, the soil pH decreased to 6.9, the available iron content increased by 0.8 mg / kg, the percentage of yellowed leaves on citrus trees decreased from 28% to 6%, and the yield increased by 18%.

[0027] Example 4 (Moderately alkaline soil + high citrus peel residue ratio) The fertilizer preparation, by weight percentage, consisted of 44.6% citrus peel residue, 20% a mixture of sawdust and straw powder (2:1), 15% a mixture of rapeseed meal and soybean meal powder (2:1), 20% a mixture of cow dung and sheep dung (1:1), and 0.4% ferrous sulfate. A mixed pre-fermentation scheme was adopted: the pretreated citrus peel residue was mixed with 0.3% compound biological agent and all other organic raw materials, and the moisture content was adjusted to 60%. Anaerobic fermentation was carried out at 30℃ for 15 days to complete the pre-fermentation. Then, the mixture was transferred to the aerobic fermentation stage, and the moisture content was adjusted to 55%. 0.1% compound biological agent was inoculated, and aerobic fermentation was carried out at 30℃ for 20 days, turning the mixture every 3 days. After fermentation, the mixture was dried to a moisture content of 20%, and ferrous sulfate was added and mixed thoroughly to obtain granular organic fertilizer.

[0028] This soil amendment application is for moderately alkaline citrus orchards with a pH of 8.0, using 2000 kg of this organic fertilizer per acre. 1400 kg (70%) is applied before spring budding, and 600 kg (30%) is applied at the end of June, using a hole application method with a depth of 25 cm and a diameter of 20 cm. After one growing season, the soil pH decreased to 7.1, the organic matter content increased by 0.7 percentage points, the yellowing symptoms of citrus trees completely disappeared, the soluble solids content of the fruit increased by 1.2 percentage points, and the yield per acre increased by 25%.

[0029] Example 5 (Slightly alkaline soil + all types of livestock and poultry manure) The fertilizer preparation, by weight percentage, consisted of 41.65% citrus peel residue, 20% a mixture of sawdust and straw powder (1:1), 18% a mixture of rapeseed meal powder and soybean meal powder (1:1), 20% a mixture of chicken manure, cow manure, and sheep manure (1:1:1), and 0.35% ferrous sulfate. A mixed pre-fermentation scheme was adopted: the citrus peel residue was mixed with 0.2% compound biological agent and all organic raw materials, the moisture content was adjusted to 58%, and anaerobic fermentation was carried out at 28℃ for 18 days; then it was transferred to aerobic fermentation, the moisture content was adjusted to 52%, 0.08% compound biological agent was inoculated, and aerobic fermentation was carried out at 28℃ for 22 days, turning the mixture every 4 days; after drying to a moisture content of 22%, ferrous sulfate was added to obtain powdered organic fertilizer.

[0030] Soil amendment application is used for slightly alkaline citrus orchards in mountainous areas with a pH of 7.3, applying 1000 kg of organic fertilizer per acre. 650 kg (65%) is applied before bud break in spring, and 350 kg (35%) is applied in early July, using a circular trench application method, with a trench depth of 22 cm and a width of 18 cm. After one growing season, the soil pH decreased to 6.7, water and fertilizer retention capacity increased by 15%, the proportion of yellowed leaves on citrus trees decreased from 30% to 5%, and yield per acre increased by 21%.

[0031] Example 6 (Moderately alkaline soil + high ferrous sulfate ratio) The fertilizer preparation, by weight percentage, consisted of 40.5% citrus peel residue, 22% a mixture of sawdust and straw powder (1:2), 17% a mixture of rapeseed meal and soybean meal powder (2:1), 20% a mixture of chicken manure and cow manure (2:1), and 0.5% ferrous sulfate. A separate biogas production scheme was adopted: the citrus peel residue was inoculated with 0.25% compound biological agent and anaerobic fermented for 17 days at 56% moisture content and 29℃ to obtain biogas slurry; the biogas slurry was mixed with the remaining raw materials and inoculated with 0.07% compound biological agent, then aerobic fermented for 23 days at 53% moisture content and 29℃, turning the mixture every 4 days; after drying to a moisture content of 23%, ferrous sulfate was added to obtain granular organic fertilizer.

[0032] Soil amendment application is used for moderately alkaline citrus orchards with a pH of 7.9, applying 2000 kg of organic fertilizer per acre. 1300 kg (65%) is applied after harvest, and 700 kg (35%) is applied in early July, using hole application methods with a depth of 30 cm and a diameter of 25 cm. After one growing season, the soil pH drops to 7.0, the available iron content increases by 1.5 mg / kg, citrus yellowing is completely eradicated, the marketable fruit rate increases by 20%, and the yield per acre increases by 27%.

[0033] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A bio-organic fertilizer suitable for improving alkaline soil, characterized in that, By weight percentage, it consists of the following raw materials: 40.00%-50.00% citrus peel residue, 20.00%-30.00% a mixture of sawdust and straw powder, 15.00%-20.00% a mixture of rapeseed meal powder and soybean meal powder, 20.00%-30.00% a mixture of chicken manure, cow manure and sheep manure, and 0.25%-0.50% ferrous sulfate.

2. The bio-organic fertilizer according to claim 1, characterized in that, The mixing ratio of sawdust to straw powder is 1:1-2:1; the mixing ratio of rapeseed meal powder to soybean meal powder is 1:1-2:1; and the mixing ratio of chicken manure, cow manure, and sheep manure is 1:1:1-2:1:

1.

3. A method for preparing the bio-organic fertilizer according to claim 1, characterized in that, Includes the following steps: Step A: Raw material pretreatment: Crush citrus peel residue, sawdust, straw powder, vegetable residue powder, and soybean meal powder to a particle size of 0.5-1cm. Dry chicken manure, cow manure, and sheep manure to a moisture content of 40%-50% and remove impurities. Step B: Preparation of citrus biogas slurry. Either Option 1 or Option 2 can be used. Option 1 involves inoculating citrus peel residue with compound biological agents and anaerobic fermentation for 15-20 days to obtain biogas slurry. Option 2 involves mixing citrus peel residue with compound biological agents and other organic raw materials and anaerobic fermentation for 15-20 days. Step C: Mixed fermentation. Adjust the moisture content of the material obtained in step B to 50%-55%, inoculate with compound biological agents, and ferment aerobically for 20-25 days, turning it over every 3-5 days. Step D: Finished product preparation. The fermented material is dried until the moisture content is less than 30%, then ferrous sulfate is added and mixed evenly to obtain powdered or granular organic fertilizer.

4. The preparation method according to claim 3, characterized in that, The compound biological agent is composed of Bacillus subtilis, yeast and lactic acid bacteria in a ratio of 1:1:

1. The amount added in step B is 0.1%-0.3% of the weight of citrus peel residue, and the amount added in step C is 0.05%-0.1% of the total material weight.

5. An application of the bio-organic fertilizer according to claim 1 in an orange grove, characterized in that, Includes the following: (1) Dosage: Apply 1000-1500 kg per mu to citrus orchards with pH value of 6.5-7.5, and apply 1500-2000 kg per mu to citrus orchards with pH value of 7.5-8.0; (2) Application time: Apply twice. The first application is before spring budding or before and after fruit harvest, accounting for 60%-70% of the total amount. The second application is from the end of June to the beginning of July, accounting for 30%-40% of the total amount. (3) Application method: Apply by trenching or hole application. Dig trenches / holes around the drip line of the fruit trees, mix the organic fertilizer with the topsoil, backfill and cover with new soil.

6. The application of the bio-organic fertilizer according to claim 5 in an orange grove, characterized in that, The trenches used for trenching are 30-40cm deep and 15-20cm wide, while the holes used for hole application are 30-40cm deep and 20-30cm in diameter.

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