A kind of nitrogen-rich and phosphorus-rich organic fertilizer and preparation method thereof

Abstract

The present invention provides a nitrogen-rich and phosphorus-rich organic fertilizer and a preparation method thereof, and relates to the technical field of organic fertilizers. The nitrogen-rich and phosphorus-rich organic fertilizer of the present invention comprises the following raw materials in parts by mass: 1.05 to 2.45 parts of raffinate, 10 parts of bagasse, 10 parts of tobacco powder, and 80 parts of cow dung. The present invention uses raffinate in the composting process of organic solid waste, effectively controlling nitrogen loss and promoting the improvement of the quality of compost products. The addition of raffinate increases the nutritional value of the organic fertilizer, and also adds inorganic phosphorus to the organic fertilizer, which can effectively protect the inorganic phosphorus from being fixed by the soil, thereby significantly improving the utilization rate of the organic fertilizer of the present invention and being beneficial to the growth of crops.

Description

Technical Field

[0001] The invention provides a nitrogen-rich and phosphorus-rich organic fertilizer and a preparation method thereof, belonging to the technical field of organic fertilizers. Background Art

[0002] In recent years, the degradation of compost quality and odor emissions from composting plants caused by ammonia release during composting have been a hot topic of research. Based on the patterns of ammonia loss, researchers have adopted various approaches to control it. Lowering the pH of the material through acid washing is an effective measure, which controls nitrogen by affecting the fermentation process, reducing NH3 production, and retaining more nitrogen nutrients. For the past few decades, traditional manure acidification has mostly been performed using sulfuric acid, which converts ammonia in stored manure into non-volatile ammonium ions. However, the use of sulfuric acid also has some limitations and criticisms, such as high sulfur input to the soil, corrosiveness, and the formation of foam, hydrogen sulfide, and aerosol particles, which are harmful to animal, farmer, and environmental health.

[0003] Raffinate acid is a byproduct produced during the production of high-purity phosphoric acid using solvent extraction. It contains approximately 45% P2O5 and is highly acidic, making it both valuable and difficult to utilize. Currently, the resource utilization of raffinate acid is limited, with a small amount used primarily as a raw material for fertilizer-grade or industrial-grade monoammonium phosphate (MAP), diammonium phosphate (DAP), and feed-grade calcium phosphate. However, due to the high impurity content and viscosity of raffinate acid, the production capacity of the equipment is significantly limited. During the ammoniation of raffinate acid to produce MAP and DAP, equipment often scales, resulting in excessively high product moisture, reduced nitrogen content, and low product quality. Due to the acidity of raffinate acid and its phosphorus content, adding it to a compost pile could affect the composting process, similar to other phosphate additives proposed in previous studies.

[0004] Therefore, raffinate acid is expected to be used as an effective acidic additive in composting, on the one hand to increase the N and P nutrient content of compost products, and on the other hand to promote the resource utilization of raffinate acid. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a nitrogen-rich and phosphorus-rich organic fertilizer and a preparation method thereof. The present invention uses raffinate acid in the composting process of organic solid waste, effectively controls nitrogen loss, and promotes the improvement of the quality of compost products. The addition of raffinate acid increases the nutritional value of organic fertilizer. The large amount of inorganic phosphorus contained in raffinate acid naturally mixes with the compost product during the composting process to form an organic-inorganic compound fertilizer. At the same time, since inorganic phosphorus is added to the organic fertilizer, the organic acids produced during the composting process, including humic acid, can effectively protect the inorganic phosphorus from being fixed by the soil, thereby significantly improving its utilization rate, which is beneficial to the growth of crops.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A nitrogen- and phosphorus-rich organic fertilizer comprises the following raw materials in parts by weight:

[0008] 1.05-2.45 parts of raffinate, 10 parts of bagasse, 10 parts of tobacco dust, and 80 parts of cow dung.

[0009] The present invention also provides a method for preparing nitrogen-rich and phosphorus-rich organic fertilizer, comprising the following steps:

[0010] (1) weighing bagasse, tobacco dust and cow dung in proportion and mixing them evenly to obtain a mixed material;

[0011] (2) spraying the raffinate into the mixed material in proportion, mixing them evenly to obtain a compost material, and ventilating and stacking the compost material for fermentation to obtain a nitrogen- and phosphorus-rich organic fertilizer.

[0012] Preferably, the moisture content of the compost material in step (2) is 65-70%.

[0013] Preferably, the mass ratio of C / N in the compost material in step (2) is 15 to 25.

[0014] Preferably, the compost material in step (2) is mixed with water in a mass ratio of 1:10, and the pH value of the solution is measured to be 5.15-6.03.

[0015] Preferably, the fermentation time in step (2) is 35 days.

[0016] Preferably, during the ventilated stacking fermentation process, the fermentation temperature is maintained at 50° C.-65° C. for 7 days, and the ventilation volume is controlled at 0.3-0.6 L / min / kg dry matter.

[0017] Compared with the prior art, the present invention

[0018] 1) The operating method of the present invention is simple and easy to operate, and ammonia volatilization is controlled in situ during the composting fermentation process, providing a solution to the odor problem in composting plants;

[0019] (2) The compost product provided by the present invention has a nutrient content far higher than that of ordinary compost and has higher nutritional value and market potential;

[0020] (3) Compared with ordinary compost, the compost product of the present invention effectively makes up for the defect of low and slow release of phosphorus nutrients as an organic fertilizer. It can meet the needs of crop growth with the phosphorus of this product during application, without the need for additional chemical phosphorus fertilizer. It is a high-quality organic fertilizer;

[0021] (4) The compost product provided by the present invention is expected to replace chemical phosphate fertilizers, reduce the use of non-renewable chemical phosphate fertilizers, and solve the problem of resource utilization of residual acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The daily NH3 emissions during the composting fermentation process of Examples 1 to 3 and Comparative Example 1;

[0023] Figure 2 is the cumulative emission of NH3 during the composting fermentation process of Examples 1 to 3 and Comparative Example 1;

[0024] Figure 3 The total nutrient content of the organic fertilizers prepared in Examples 1 to 3 and Comparative Example 1. DETAILED DESCRIPTION

[0025] To make the purpose, technical solutions and advantages of the present invention more clear, the preferred embodiments of the present invention are further described in detail below with reference to the examples. Based on the examples in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] This embodiment provides a nitrogen-rich and phosphorus-rich organic fertilizer, which is prepared from the following raw materials in parts by mass: 1.05 parts of raffinate, 10 parts of bagasse, 10 parts of tobacco powder, and 80 parts of cow dung.

[0028] The preparation method of the nitrogen-rich and phosphorus-rich organic fertilizer of the present embodiment comprises the following steps:

[0029] (1) weighing bagasse, tobacco dust and cow dung in proportion and mixing them evenly to obtain a mixed material;

[0030] (2) spraying the raffinate into the mixture in proportion, and mixing uniformly to obtain a compost material, wherein the compost material has a moisture content of 66%, a C / N mass ratio of 20, and a pH of 6.03 (the compost material and water are mixed in a mass ratio of 1:10, and the pH value of the solution is measured);

[0031] (3) The compost material is piled and fermented under ventilation; mechanical forced ventilation is adopted during the fermentation process, the ventilation volume is controlled at 0.5 L / min / kg dry matter, the fermentation temperature is maintained at 50° C. to 65° C. for 7 days, and the compost is turned regularly. After 35 days of fermentation, nitrogen-rich and phosphorus-rich organic fertilizer is obtained, which is recorded as T1.

[0032] Example 2

[0033] This embodiment provides a nitrogen-rich and phosphorus-rich organic fertilizer, which is prepared from the following raw materials in parts by mass: 1.75 parts of raffinate, 10 parts of bagasse, 10 parts of tobacco powder, and 80 parts of cow dung.

[0034] The preparation method of the nitrogen-rich and phosphorus-rich organic fertilizer of the present embodiment comprises the following steps:

[0035] (1) weighing bagasse, tobacco dust and cow dung in proportion and mixing them evenly to obtain a mixed material;

[0036] (2) spraying the raffinate into the mixture in proportion, and mixing uniformly to obtain a compost material, wherein the compost material has a moisture content of 67%, a C / N mass ratio of 20, and a pH of 5.39 (the compost material and water are mixed in a mass ratio of 1:10, and the pH value of the solution is measured);

[0037] (3) The compost material is piled and fermented under ventilation; mechanical forced ventilation is adopted during the fermentation process, the ventilation volume is controlled at 0.5 L / min / kg dry matter, the fermentation temperature is maintained at 50° C. to 65° C. for 7 days, and the compost is turned regularly. After 35 days of fermentation, nitrogen-rich and phosphorus-rich organic fertilizer is obtained, which is recorded as T2.

[0038] Example 3

[0039] This embodiment provides a nitrogen-rich and phosphorus-rich organic fertilizer, which is prepared from the following raw materials in parts by mass: 2.45 parts of raffinate, 10 parts of bagasse, 10 parts of tobacco powder, and 80 parts of cow dung.

[0040] The preparation method of the nitrogen-rich and phosphorus-rich organic fertilizer of the present embodiment comprises the following steps:

[0041] (1) weighing bagasse, tobacco dust and cow dung in proportion and mixing them evenly to obtain a mixed material;

[0042] (2) spraying the raffinate into the mixed material in proportion, and mixing uniformly to obtain a compost material, wherein the compost material has a moisture content of 68%, a C / N mass ratio of 20, and a pH of 5.15 (the compost material and water are mixed in a mass ratio of 1:10, and the pH value of the solution is measured);

[0043] (3) The compost material is piled and fermented under ventilation; mechanical forced ventilation is adopted during the fermentation process, the ventilation volume is controlled at 0.5 L / min / kg dry matter, the fermentation temperature is maintained at 50° C. to 65° C. for 7 days, and the compost is turned regularly. After 35 days of fermentation, nitrogen-rich and phosphorus-rich organic fertilizer is obtained, which is recorded as T3.

[0044] Comparative Example 1

[0045] A method for preparing organic fertilizer comprises the following steps:

[0046] 10 parts of bagasse, 10 parts of tobacco powder, 80 parts of cow dung.

[0047] (1) Bagasse, tobacco dust, and cow dung were weighed in proportion and mixed uniformly to obtain a mixture, wherein the mixture had a moisture content of 66%, a C / N mass ratio of 20, and a pH of 7.64 (the mixture was mixed with water in a mass ratio of 1:10, and the pH value of the solution was measured);

[0048] (3) The mixed material is piled and fermented under ventilation; mechanical forced ventilation is adopted during the fermentation process, the ventilation volume is controlled at 0.5 L / min / kg dry matter, the fermentation temperature is kept at 50° C. to 65° C. for 7 days, and the pile is turned regularly. Ordinary organic fertilizer is obtained after fermentation for 35 days, which is recorded as CK.

[0049] The total nitrogen and total phosphorus contents in the nitrogen-rich and phosphorus-rich organic fertilizers prepared in Examples 1 to 3 of the present invention are significantly higher than those in ordinary compost. The total nitrogen is 1.7 to 3.3 g / kg higher than that in ordinary compost (CK group), the total phosphorus is 18.87 to 39.17 g / kg higher, and the total nutrients are 20.31 to 42.23 g / kg higher. Therefore, the quality of the fertilizer product is significantly increased. The pH of the organic fertilizer of the present invention is 7.17-8.19, which meets the requirements of the organic fertilizer standard (NYT525-2021).

[0050] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

Claims

1. A nitrogen-rich and phosphorus-rich organic fertilizer, characterized in that Including the following raw materials by weight: 1.05-2.45 parts of raffinate, 10 parts of bagasse, 10 parts of tobacco dust, 80 parts of cow dung; The preparation method of the nitrogen-rich and phosphorus-rich organic fertilizer comprises the following steps: (1) weighing bagasse, tobacco dust and cow dung in proportion and mixing them evenly to obtain a mixed material; (2) spraying the raffinate into the mixture in proportion, mixing uniformly to obtain a compost material, and ventilating and stacking the compost material for fermentation to obtain a nitrogen-rich and phosphorus-rich organic fertilizer; During the fermentation process of step (2) with ventilation and stacking, the fermentation temperature is maintained at 50° C. to 65° C. for 7 days, and the ventilation rate is controlled at 0.3 to 0.6 L / min / kg of dry matter.

2. Nitrogen-rich and phosphorus-rich organic fertilizer as claimed in claim 1, is characterized in that, The moisture content of the compost material in step (2) is 60-70%.

3. Nitrogen-rich and phosphorus-rich organic fertilizer as claimed in claim 1, is characterized in that, The mass ratio of C / N in the compost material in step (2) is 15 to 25.

4. Nitrogen-rich and phosphorus-rich organic fertilizer as claimed in claim 1, is characterized in that, The compost material in step (2) is mixed with water in a mass ratio of 1:10, and the pH value of the solution is measured to be 5.15-6.

03.

5. Nitrogen-rich and phosphorus-rich organic fertilizer as claimed in claim 1, is characterized in that, The fermentation time in step (2) is 35 days.

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