Biochar-based slow-release sulfur fertilizer as well as preparation method and application thereof

Abstract

The invention provides a charcoal-based slow-release sulfur fertilizer as well as a preparation method and application thereof, and belongs to the technical field of soil nutrient synergism. Comprising the following steps: S1, cleaning, drying, crushing and sieving trimmed apple branches to obtain apple wood powder for later use; s2, the screened apple wood powder is heated and carbonized, and apple wood biochar is obtained; s3, preparing a sulfur-containing fertilizer and deionized water into a solution, standing, precipitating, filtering, and retaining the solution; s4, adding the apple wood biochar into the mixed solution in the step S3, stirring and reacting, standing until the biochar-based slow-release sulfur fertilizer is settled, and filtering to obtain the biochar-based slow-release sulfur fertilizer; s5, the biochar-based slow-release sulfur fertilizer is purified with absolute ethyl alcohol, then washed with deionized water and dried, and the biochar-based slow-release sulfur fertilizer is obtained, growth and development of crops are promoted, and the biochar-based slow-release sulfur fertilizer has the advantages of being capable of promoting crop growth, easy to prepare, environmentally friendly and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of soil nutrient enhancement, and particularly relates to a biochar-based slow-release sulfur fertilizer, a preparation method thereof, and an application thereof. Background Art

[0002] Sulfur is an essential element for the healthy growth of crops. Especially in intensive agriculture, with the popularization of high-concentration chemical fertilizers, the phenomenon of sulfur deficiency in soil has become increasingly prominent. As a component of sulfur-containing amino acids, sulfur is a key raw material for plant protein synthesis. Sulfur deficiency will lead to the obstruction of protein synthesis, affect cell division and plant growth. At the same time, sulfur is also involved in the synthesis of chlorophyll. Sulfur deficiency will indirectly cause leaf chlorosis, reduce photosynthetic efficiency, affect the accumulation of carbohydrates, and lead to poor crop growth. At the same time, sulfur is an active component of many enzymes, participating in nitrogen metabolism, energy conversion, and redox reactions, which can improve the stress resistance and flavor quality of crops, promote root growth, and enhance the absorption capacity of crops for water and mineral elements (such as nitrogen and phosphorus), especially crucial for root development in the seedling stage. Therefore, how to scientifically supplement sulfur fertilizer can not only correct the deficiency symptoms, but also improve crop yield, quality, and stress resistance, which is one of the important measures to achieve sustainable agriculture.

[0003] Agricultural waste apple wood branches are selected as the raw material of the biochar-based slow-release sulfur fertilizer because agricultural waste apple wood branches are widely sourced, almost cost-free, and very environmentally friendly. Biochar is a carbon-rich solid product made from various agricultural waste biomasses through high-temperature anaerobic pyrolysis. It has a porous structure, a high specific surface area, and various oxygen-containing functional groups, so it is often used to adsorb and enrich various nutrient elements (such as sulfur, nitrogen, and phosphorus, etc.). In order to increase sulfur elements in sulfur-deficient soil, reduce the application of chemical fertilizers, enhance the stress resistance of crops, promote crop growth, and improve the sulfur nutrient release efficiency of biochar to make it more effective and applicable. Therefore, the biochar is impregnated and enriched to prepare a biochar-based slow-release sulfur fertilizer, increase the sulfur release ability of the biochar, apply it to the soil, increase the sulfur in the soil, and thus promote crop growth.

[0004] Therefore, in order to improve sulfur-deficient soil, it is a technical problem that needs to be urgently solved by researchers in this field to provide a biochar-based slow-release sulfur fertilizer that can increase soil sulfur, enhance crop stress resistance, promote crop growth, be simple to prepare, and have a low cost. Summary of the Invention

[0005] The purpose of the present invention is to provide a biochar-based slow-release sulfur fertilizer, a preparation method thereof, and an application thereof. Based on biochar, the biochar is prepared into a biochar-based slow-release sulfur fertilizer through an impregnation and enrichment method to achieve the promotion of crop growth and development. The present invention has the advantages of promoting crop growth, being simple to prepare, and being environmentally friendly.

[0006] The technical solution of the present invention is realized as follows:

[0007] The present invention provides a preparation method of a biochar-based slow-release sulfur fertilizer, comprising the following steps:

[0008] S1. Wash, dry, crush and screen the pruned apple branches to obtain apple wood powder for standby;

[0009] S2. Heat and carbonize the selected apple wood powder to obtain apple wood biochar;

[0010] S3. Prepare a solution of sulfur-containing fertilizer and deionized water, let it stand for precipitation, filter out the impurities in the solution, and retain the solution;

[0011] S4. Add the apple wood biochar to the mixed solution in step S3 according to a certain proportion of the weight of the sulfur-containing fertilizer added in step S3. After stirring and reacting, let it stand until the biochar-based slow-release sulfur fertilizer settles, and then filter to obtain the biochar-based slow-release sulfur fertilizer;

[0012] S5. Purify the biochar-based slow-release sulfur fertilizer with absolute ethanol, wash it with deionized water, and dry it to obtain the biochar-based slow-release sulfur fertilizer.

[0013] As a further improvement of the present invention, the temperature of drying in step S1 is 55-65°C, and the mesh number of the sieve for screening is 50-100 meshes.

[0014] As a further improvement of the present invention, the conditions for heating and carbonizing in step S2 are heating to 500-600°C at a heating rate of 10-20°C / min in an atmosphere of nitrogen and maintaining a constant temperature for 5-10 h.

[0015] As a further improvement of the present invention, the sulfur content of the sulfur-containing fertilizer in step S3 is 85-90%.

[0016] As a further improvement of the present invention, the mass ratio of the sulfur-containing fertilizer to deionized water in step S3 is 2-4:1.

[0017] As a further improvement of the present invention, the proportion of the apple wood biochar in the weight of the sulfur-containing fertilizer in step S4 is 20-45 wt%.

[0018] As a further improvement of the present invention, the time for stirring and reacting in step S4 is 3-5 h.

[0019] As a further improvement of the present invention, the time for purification in step S5 is 10-14 h, the temperature of drying is 55-65°C, and the time is 20-28 h.

[0020] The present invention further protects a biochar-based slow-release sulfur fertilizer prepared by the above preparation method.

[0021] The present invention further protects the application of the above-mentioned biochar-based slow-release sulfur fertilizer in enhancing soil nutrients.

[0022] The present invention has the following beneficial effects:

[0023] The biochar-based slow-release sulfur fertilizer prepared by the present invention is prepared into a biochar-based slow-release sulfur fertilizer by the method of impregnation and enrichment on the basis of biochar, realizing the promotion of the growth and development of crops. The present invention has the advantages of promoting crop growth, simple preparation and environmental friendliness. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It shows the influence of the biochar-based slow-release sulfur fertilizer in the present invention on the height of corn;

[0026] Figure 2 It shows the influence of the biochar-based slow-release sulfur fertilizer in the present invention on the fresh weight of corn;

[0027] Figure 3 It shows the influence of the biochar-based slow-release sulfur fertilizer in the present invention on the dry weight of corn;

[0028] Figure 4 It shows the influence of the biochar-based slow-release sulfur fertilizer in the present invention on the fresh weight of corn roots;

[0029] Figure 5 It shows the influence of the biochar-based slow-release sulfur fertilizer in the present invention on the dry weight of corn roots. Detailed Embodiments

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0031] Comparative Example 1

[0032] This comparative example provides a preparation method of apple wood biochar, including the following steps:

[0033] S1. Wash the apple tree branches in the full fruit period, place them in an oven at 60 °C for drying, and crush them into powder by a crusher, and pass through a sieve with 80 meshes to obtain apple wood powder for standby;

[0034] S2. Put the selected apple wood powder into a tubular muffle furnace, heat it up and carbonize it under the condition of nitrogen oxygen limitation, heat it to 550 °C at a heating rate of 15 °C / min, and keep it pyrolyzed for 8 h to obtain apple wood biochar (BC).

[0035] Example 1

[0036] This example provides a preparation method of a biochar-based slow-release sulfur fertilizer, which includes the following steps:

[0037] S1. Wash the apple branches in the full fruit-bearing period, dry them in an oven at 60 °C, crush them into powder by a crusher, and pass through a 80-mesh sieve to obtain apple wood powder for standby;

[0038] S2. Put the selected apple wood powder into a tubular muffle furnace, heat it up and carbonize it under the condition of nitrogen oxygen limitation, heat it to 550 °C at a heating rate of 15 °C / min, and keep it pyrolyzed to obtain apple wood biochar;

[0039] S3. Prepare a solution by mixing a sulfur-containing fertilizer (sulfur content 87%) and deionized water at a mass ratio of 3:1, stir it rapidly, set the rotation speed to 800 r / min, stir for 2 h to dissolve the sulfur-containing fertilizer in deionized water, let it stand and precipitate for 2 h, filter out the impurities in the solution, and retain the solution;

[0040] S4. Slowly add the obtained apple wood biochar to the mixed solution in step S3 at 21.50% of the weight of the sulfur-containing fertilizer added in step S3, stir it rapidly, set the rotation speed to 800 r / min, stir for 4 h, and then let it stand until the biochar-based slow-release sulfur fertilizer settles, and filter out the biochar-based slow-release sulfur fertilizer (sulfur content 1%);

[0041] S5. Purify the biochar-based slow-release sulfur fertilizer with absolute ethanol for 12 h, wash it with deionized water, dry it in an oven at 60 °C for 24 h, and finally obtain the biochar-based slow-release sulfur fertilizer (SB1).

[0042] Example 2

[0043] This example provides a preparation method of a biochar-based slow-release sulfur fertilizer, which includes the following steps:

[0044] S1. Wash the apple branches in the full fruit-bearing period, dry them in an oven at 60 °C, crush them into powder by a crusher, and pass through a 80-mesh sieve to obtain apple wood powder for standby;

[0045] S2. Put the selected apple wood powder into a tube furnace, heat it for carbonization under the condition of nitrogen-limited oxygen, heat it at a heating rate of 15 °C / min to 550 °C, and keep it pyrolyzed for 8 h to obtain apple wood biochar (BC);

[0046] S3. Prepare a solution by mixing sulfur-containing fertilizer (sulfur content 87%) and deionized water at a mass ratio of 3:1, stir it rapidly, set the rotation speed to 800 r / min, stir for 2 h to dissolve the sulfur-containing fertilizer in deionized water, let it stand and precipitate for 2 h, filter out the impurities in the solution, and retain the solution;

[0047] S4. Slowly add the obtained apple wood biochar to the mixed solution in S3 at 43.00% of the weight of the sulfur-containing fertilizer added in S3, stir it rapidly, set the rotation speed to 800 r / min, stir for 4 h, and then let it stand until the biochar-based slow-release sulfur fertilizer settles, and filter out the biochar-based slow-release sulfur fertilizer (sulfur content 2%);

[0048] S5. Purify the biochar-based slow-release sulfur fertilizer with absolute ethanol for 12 h, wash it with deionized water, dry it in an oven at 60 °C for 24 h, and finally obtain the biochar-based slow-release sulfur fertilizer (SB2).

[0049] Test Example 1 explores the effect of biochar-based slow-release sulfur fertilizer on corn growth

[0050] Carry out a pot experiment in an environment of 26 °C and 60% humidity. Apply SB1 (sulfur content 1%) prepared in Example 1 and SB2 (sulfur content 2%) prepared in Example 2 to the soil at two different application ratios. The CK group uses the apple wood biochar (BC) prepared in Comparative Example 1: 1.0 wt% and 2.0 wt% of the soil weight. Sow corn seeds in each pot. After 30 days of continuous growth, collect the corn seedling plants, and measure the growth index of the obtained corn seedlings. The growth index includes corn height, fresh weight, dry weight, root fresh weight, and root dry weight. The results are as Figures 1-5 shown.

[0051] When applying 1.0 wt%, the corn heights of SB1 and SB2 increased by 5.22% and 2.34% respectively; the corn fresh weights increased by 78.28% and 66.67% respectively; the corn dry weights increased by 57.14% and 57.14% respectively; the corn root fresh weights increased by 41.01% and 11.15% respectively; the corn root dry weights increased by 61.54% and 76.92% respectively

[0052] When applied at 2.0 wt%, the heights of SB1 and SB2 maize increased by 2.98% and 3.72%, respectively; the fresh weights of maize increased by 24.24% and 38.38%, respectively; the dry weights of maize increased by 57.14% and 78.57%, respectively; the fresh weights of maize roots increased by 64.39% and 33.81%, respectively; the dry weights of maize roots increased by 96.15% and 73.08%, respectively.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a biochar-based slow-release sulfur fertilizer, characterized in that, It includes the following steps: S1. Wash, dry, crush and sieve the pruned apple tree branches to obtain apple wood powder for standby; S2. Heat and carbonize the screened apple wood powder to obtain apple wood biochar; S3. Prepare a solution of sulfur-containing fertilizer and deionized water, let it stand for precipitation, filter out the impurities in the solution, and retain the solution; S4. Add the apple wood biochar to the mixed solution in S3 in a certain proportion according to the weight of the sulfur-containing fertilizer added in S3. After stirring and reacting, let it stand until the biochar-based slow-release sulfur fertilizer settles, then filter to obtain the biochar-based slow-release sulfur fertilizer; S5. Purify the biochar-based slow-release sulfur fertilizer with absolute ethanol, wash it with deionized water, and dry it to obtain the biochar-based slow-release sulfur fertilizer.

2. The preparation method according to claim 1, characterized in that, In step S1, the drying temperature is 55 - 65°C, and the mesh number of the sieve for sieving is 50 - 100 meshes.

3. The preparation method according to claim 1, characterized in that, In step S2, the conditions for heating and carbonizing are heating to 500 - 600°C at a heating rate of 10 - 20°C / min in a nitrogen atmosphere and maintaining a constant temperature for 5 - 10 h.

4. The preparation method according to claim 1, characterized in that, In step S3, the sulfur content of the sulfur-containing fertilizer is 85 - 90%.

5. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of the sulfur-containing fertilizer to deionized water is 2 - 4:

1.

6. The preparation method according to claim 1, wherein, In step S4, the proportion of the apple wood biochar in the weight of the sulfur-containing fertilizer is 20 - 45 wt%.

7. The preparation method according to claim 1, characterized in that, In step S4, the stirring reaction time is 3 - 5 h.

8. The preparation method according to claim 1, characterized in that, In step S5, the purification time is 10 - 14 h, the drying temperature is 55 - 65°C, and the time is 20 - 28 h.

9. A biochar-based slow-release sulfur fertilizer prepared by the preparation method according to any one of claims 1 - 8.

10. An application of the biochar-based slow-release sulfur fertilizer according to claim 9 in soil nutrient enhancement.

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