Special cow dung organic fertilizer for saline-alkali soil and preparation method thereof

Abstract

The invention provides a special cow dung organic fertilizer for saline-alkali soil and a preparation method thereof, and the preparation method specifically comprises the following steps: 1, carrying out mixed fermentation on a cow dung substrate and compound bacterial powder, 2, adding modified charcoal and salt-tolerant bacterial powder, mixing and decomposing, 3, mixing and granulating with desulfurized gypsum-vermiculite-quartz sand micro-powder, humus soil and trace elements, and 4, carrying out granulation on the granules to obtain the special cow dung organic fertilizer for saline-alkali soil. The special cow dung organic fertilizer for saline-alkali soil is obtained; through a multi-strain synergistic fermentation process, modified functional material compounding and stage temperature-controlled decomposition, the defects of an existing saline-alkali soil modifier in the aspects of microbial activity, nutrient release efficiency, soil structure remediation and the like are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of saline-alkali land improvement, and particularly relates to a special cow dung organic fertilizer for saline-alkali land and a preparation method thereof. Background Art

[0002] Due to the high content of soluble salts (such as Na+ and Cl-), high pH value (alkaline), soil structure compaction, and lack of organic matter in the soil of saline-alkali land, it is difficult for plant roots to absorb water and nutrients are blocked, severely restricting crop growth. In order to develop and utilize saline-alkali land as arable land and enable crops to grow healthily on saline-alkali land, the geology is often improved by using modifiers or fertilizers to reduce the impact of saline-alkali land on crops.

[0003] However, the existing modifiers and fertilization methods have the following technical defects: 1) Direct application of traditional organic fertilizers (such as ordinary cow dung) without fermentation will not only cause seedling burning, but also, due to the low microbial activity in saline-alkali land, the organic matter decomposes slowly and it is difficult to release effective nutrients. 2) Existing chemical modifiers (such as desulfurized gypsum and humic acid) can neutralize alkalinity and reduce salt content in the short term, but long-term use is likely to cause soil compaction and lack of organic matter supplementation, making it difficult to improve the soil microbial environment. 3) The salt tolerance of single microbial agents (such as Bacillus subtilis) is limited, and the survival rate in saline-alkali land is low, making it difficult to play a continuous role. 4) The adsorption capacity of ordinary biochar is limited, the fixing effect on salt ions is poor, and there is no synergistic effect with microorganisms.

[0004] Therefore, providing a special cow dung organic fertilizer for saline-alkali land that can both effectively improve the geology of saline-alkali land and increase the nutrient release rate has become an urgent problem to be solved. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a special cow dung organic fertilizer for saline-alkali land and a preparation method thereof, which specifically includes the following steps.

[0006] Step 1: Inoculate a composite bacterial powder into the cow dung matrix, stir and ferment at 60-70 °C for 4-6 days, turn the pile once every 12-14 h, and the rotation speed is 10-20 r / min.

[0007] Step 2: After fermentation is completed, mix with modified biochar and inoculate a salt-tolerant bacterial powder, and decompose at 40-50 °C for 10-15 days, turn the pile once every 1-2 days, and maintain aerobic conditions for 3-5 h and anaerobic conditions for 1-2 h during decomposition.

[0008] Step 3: After decomposition is completed, dry at 30-40 °C until the water content ≤ 10%, and mix with desulfurized gypsum-vermiculite-quartz sand fine powder, humus soil and trace elements to granulate, obtaining the special cow dung organic fertilizer for saline-alkali land.

[0009] Preferably, the mass ratio of the cow dung matrix, modified biochar, composite bacterial powder, salt-tolerant bacterial powder, desulfurized gypsum-vermiculite-quartz sand fine powder, humus soil and trace elements is (70-80):(5-10):(0.5-1.2):(1.2-1.5):(10-15):(10-20):(0.5-1).

[0010] Preferably, the composite bacterial powder includes bacillus licheniformis powder and streptococcus thermophilus powder, and the mass ratio is 2:1. The salt-tolerant bacterial powder includes bacillus subtilis powder, bacillus coagulans powder and aspergillus niger spore powder, and the mass ratio is 5:3:2.

[0011] Preferably, the preparation method of the cow dung matrix in step one is to mix fresh cow dung, plant straw and cellulase, ferment at 40-50 °C for 7-10 days, turn the pile every 20-24 h, add citric acid-potassium dihydrogen phosphate solution every 2-3 days, and keep the moisture content at 50-60%. After fermentation, the cow dung matrix is obtained. Most preferably, the fresh cow dung has a moisture content of 70-80%, and the plant straw is one or more of corn straw, rice straw and wheat straw. Most preferably, the mass ratio of the fresh cow dung, plant straw and cellulase is 350:150:1, and the citric acid-potassium dihydrogen phosphate includes citric acid, potassium dihydrogen phosphate and water, and the mass ratio is 3:1:100.

[0012] Preferably, the preparation method of the modified biochar in step two is to mix citric acid residue with biomass and carbonize at 600-700 °C for 2-3 h to obtain the modified biochar. Most preferably, the mass ratio of the citric acid residue to the biomass is 1:3. Most preferably, the biomass is agricultural and forestry waste, specifically one or more of wood chips, coconut shells, rice straw, rice, corn straw, wheat straw, rice straw and bamboo.

[0013] Preferably, the preparation method of the desulfurized gypsum-vermiculite-quartz sand fine powder is to mix desulfurized gypsum, vermiculite and quartz sand according to the mass ratio of 2:5:3 and ball mill to a particle size of ≤50 μm.

[0014] The trace elements include Fe-EDTA, Zn-EDTA, magnesium sulfate, manganese sulfate and ammonium molybdate, and the mass ratio is 10:1:5:1.5:0.5.

[0015] The present invention has the following advantages:

[0016] (1) The compound bacterial powder and salt-tolerant bacterial powder of the present invention have synergistic effects. Streptococcus thermophilus accelerates high-temperature fermentation, Bacillus licheniformis decomposes cellulose, shortening the fermentation cycle; Bacillus subtilis secretes salt-tolerant enzymes, Aspergillus niger produces acid to lower the pH value, and Bacillus coagulans enhances the stability of composting, adapting to saline-alkali environments; multiple bacteria cooperate, significantly improving salt tolerance, decomposition efficiency and environmental adaptability. It avoids the problems of poor salt tolerance of traditional bacterial agents and single functions of single bacteria (such as only decomposing organic matter or nitrogen fixation).

[0017] (2) High-temperature fermentation quickly kills pathogenic bacteria, while retaining the activity of heat-resistant bacteria. During the composting stage, modified biochar is combined to adsorb salts, and the salt-tolerant bacterial powder further decomposes refractory organic matter. Aerobic-anaerobic alternating fermentation simulates the natural soil environment, promoting the formation of humic acid; temperature and oxygen are precisely controlled in stages to improve the conversion efficiency of organic matter and the content of humus. It avoids the problems of single traditional fermentation processes (such as only high-temperature composting) and the lack of adjustment of temperature control and turning frequency according to the characteristics of saline-alkali land.

[0018] (3) The synergistic application of modified biochar and desulfurized gypsum-vermiculite composite materials. Citric acid residue provides acidic functional groups for activated carbon, enhancing the adsorption capacity for Na + . Biomass such as pine sawdust forms a porous structure after carbonization, improving water and fertilizer retention. Desulfurized gypsum provides Ca 2+ to displace Na + . Vermiculite enhances the ion exchange capacity, and quartz sand improves soil permeability. Multiple materials cooperate to reduce salts, adjust the pH value, and simultaneously improve the physical structure of the soil; it avoids the problems of single pore structure of ordinary biochar and easy soil compaction when desulfurized gypsum is used alone.

[0019] (4) The present invention optimizes the ratio of cow dung matrix, modified biochar and bacterial powder to ensure the balance of organic matter and functional materials. Trace elements are supplemented in the form of chelates to supply scarce Fe and Zn in saline-alkali land, precisely matching the nutrient requirements of saline-alkali land and enhancing the stress resistance of crops, avoiding the problems of rough ratio of traditional soil improvers and lack of targeted trace element supplementation. Detailed implementation manners

[0020] The technical solutions in the embodiments of the invention are clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0021] The sources of the bacterial powder in the following examples are shown in Table 1

[0022]

[0023]

[0024] Example 1

[0025] Step 1: Mix fresh cow dung with a moisture content of 75%, corn straw, and cellulase in a mass ratio of 350:150:1, ferment at 45°C for 8 days, turn the pile once every 24 hours, add a citric acid-potassium dihydrogen phosphate solution every 2 days to maintain a moisture content of 55%. After fermentation is completed, a cow dung substrate is obtained. The citric acid-potassium dihydrogen phosphate includes citric acid, potassium dihydrogen phosphate, and water, with a mass ratio of 3:1:100.

[0026] Step 2: Mix citric acid residue and pine sawdust in a mass ratio of 1:3, carbonize at 650°C for 3 hours to obtain modified biochar.

[0027] Step 3: Mix desulfurized gypsum, vermiculite, and quartz sand in a mass ratio of 2:5:3, and ball mill to a particle size ≤50 μm.

[0028] Step 4: Inoculate the cow dung substrate with compound bacterial powder, stir and ferment at 65°C for 5 days, turn the pile once every 12 hours, and the rotation speed is 15 r / min.

[0029] Step 5: After fermentation is completed, mix with modified biochar and inoculate with salt-tolerant bacterial powder, and cure at 45°C for 12 days, turn the pile once every 2 days. During the curing period, aerobic for 4 hours and anaerobic for 2 hours.

[0030] Step 6: After curing is completed, dry at 35°C until the water content ≤10%, mix with desulfurized gypsum-vermiculite-quartz sand fine powder, humus soil, and trace elements to granulate, with a particle size of 3-5 mm, to obtain a special cow dung organic fertilizer for saline-alkali land.

[0031] The mass ratio of the cow dung substrate, modified biochar, compound bacterial powder, salt-tolerant bacterial powder, desulfurized gypsum-vermiculite-quartz sand fine powder, humus soil, and trace elements is 75:8:0.5:1.2:10:15:0.5.

[0032] The compound bacterial powder includes lichen bacillus bacterial powder and streptococcus thermophilus bacterial powder, with a mass ratio of 2:1. The salt-tolerant bacterial powder includes bacillus subtilis bacterial powder, bacillus coagulans bacterial powder, and aspergillus niger spore powder, with a mass ratio of 5:3:2. The trace elements include Fe-EDTA, Zn-EDTA, magnesium sulfate, manganese sulfate, and ammonium molybdate, with a mass ratio of 10:1:5:1.5:0.5.

[0033] Test Example 1

[0034] Select a local saline-alkali land, divide it into several plots on average, take soil samples from the 0-20 cm soil layer, and detect the soil pH value, soil salt content, and organic matter content respectively. The results are shown in Table 1.

[0035] Two groups of experiments were set up. In the control group, traditional cow manure fertilizer at 500 kg / mu was applied, and in the experimental group, the special fertilizer prepared in Example 1 at 500 kg / mu was applied. After 30 days, soil samples in the 0 - 20 cm soil layer were taken to detect the soil pH value, soil salt content, organic matter content, and Na + adsorption rate. The results are shown in Table 1. Then, corn was planted in the soils improved in the control group and the experimental group respectively. The corn planting methods and field management methods in the control group and the experimental group refer to "High-quality and High-efficiency Cultivation Techniques of Corn", Anhui Science and Technology Press, edited by Yu Qinglai. When the corn was harvested, the plant height, yield, grain protein content, and stress resistance (disease incidence rate) were detected respectively. The results are shown in Table 1.

[0036] Table 1

[0037]

[0038]

[0039] As can be seen from Table 1, the special fertilizer of the present invention can significantly improve the geology of saline-alkali land compared with traditional cow manure fertilizer, reduce the soil pH and salt content, increase the organic matter content, and can significantly improve the yield and quality of crops.

[0040] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of cow dung organic fertilizer special for saline-alkali land, characterized in that, It includes the following steps: Step 1: Inoculate the cow dung matrix with the composite bacterial powder, stir and ferment at 60 - 70 °C for 4 - 6 days, and turn the pile every 12 - 14 h; Step 2: After fermentation is completed, mix it with the modified biochar and inoculate with the salt - tolerant bacterial powder, decompose at 40 - 50 °C for 10 - 15 days, turn the pile every 1 - 2 days, keep aerobic for 3 - 5 h and anaerobic for 1 - 2 h during decomposition; Step 3: After decomposition is completed, dry it at 30 - 40 °C until the water content ≤ 10%, and mix it with the desulfurized gypsum - vermiculite - quartz sand fine powder, humus soil and trace elements to granulate, obtaining the cow dung organic fertilizer special for saline - alkali land.

2. The preparation method of a special cow dung organic fertilizer for saline-alkali land according to claim 1, characterized in that, The mass ratio of the cow dung matrix, modified biochar, composite bacterial powder, salt - tolerant bacterial powder, desulfurized gypsum - vermiculite - quartz sand fine powder, humus soil and trace elements is (70 - 80):(5 - 10):(0.5 - 1.2):(1.2 - 1.5):(10 - 15):(10 - 20):(0.5 - 1).

3. The preparation method of a special cow dung organic fertilizer for saline-alkali land according to claim 1, characterized in that, The composite bacterial powder includes bacillus licheniformis powder and streptococcus thermophilus powder, and the mass ratio is 2:

1.

4. The preparation method of a special cow dung organic fertilizer for saline-alkali land according to claim 1, characterized in that, The salt - tolerant bacterial powder includes bacillus subtilis powder, bacillus coagulans powder and aspergillus niger spore powder, and the mass ratio is 5:3:

2.

5. The preparation method of a special cow dung organic fertilizer for saline-alkali land according to claim 1, characterized in that, The preparation method of the cow dung matrix in Step 1 is to mix fresh cow dung, plant straws and cellulase, ferment at 40 - 50 °C for 7 - 10 days, turn the pile every 20 - 24 h, add the citric acid - potassium dihydrogen phosphate solution every 2 - 3 days, keep the moisture content at 50 - 60%, and obtain the cow dung matrix after fermentation is completed.

6. The preparation method of a special cow dung organic fertilizer for saline-alkali land according to claim 5, characterized in that, The mass ratio of the fresh cow dung, plant straws and cellulase is 350:150:

1.

7. The preparation method of a special cow dung organic fertilizer for saline-alkali land according to claim 5, characterized in that, The citric acid - potassium dihydrogen phosphate includes citric acid, potassium dihydrogen phosphate and water, and the mass ratio is 3:1:

100.

8. The preparation method of a special cow dung organic fertilizer for saline-alkali land according to claim 1, characterized in that, The preparation method of the modified biochar in Step 2 is to mix citric acid residue with biomass, carbonize at 600 - 700 °C for 2 - 3 h, obtaining the modified biochar.

9. The preparation method of a special cow dung organic fertilizer for saline-alkali land according to claim 8, characterized in that, The mass ratio of the citric acid residue to the biomass is 1:

3.

10. The cow dung organic fertilizer special for saline - alkali land prepared by the method according to any one of claims 1 - 9.

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