Northeast black land newly-renovated dry land barrier layer reduction method based on soil conditioner

Abstract

The invention discloses a northeast black land and dry land barrier layer reduction method based on a soil conditioner, and belongs to the technical field of soil improvement. According to the method, an organic-inorganic composite conditioner and a composite microbial agent have a synergistic effect, and a mechanical deep ploughing technology is combined, so that the problem of a barrier layer of the northeast black land and dry land is effectively solved. Wherein the organic-inorganic composite conditioner is formed by compounding humic acid, bentonite, biochar, calcium-based minerals and agricultural straw, and the composite microbial agent comprises two functional strains including phosphate solubilizing bacteria and white-rot fungi. According to the method, through the technical path of combining physical improvement and biological improvement, a straw resource utilization channel is innovatively constructed while barrier layer reduction is achieved, and the problem of environmental pollution caused by traditional straw incineration can be effectively relieved. The method has the advantages of being low in raw material cost, simple in preparation process, convenient and efficient to operate and the like, the improvement effect on the dry land barrier layer is remarkable through actual verification, and good ecological benefits and application and popularization value are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil improvement, and particularly relates to a method for reducing dryland barrier layers in newly renovated black soil in Northeast China based on a soil conditioner. Background Technique

[0002] The formation of the soil barrier layer in the black soil in Northeast China is the result of the long-term action of multiple factors: First, long-term high-intensity mechanical tillage has led to a significant increase in the bulk density of the plow pan layer (15 - 30 cm), forming a dense physical barrier layer, whose permeability coefficient is reduced by 40% - 60% compared with natural soil; Second, the combined action of the stagnant water effect formed by seasonal precipitation and the downward movement of clay particles forms a white clay layer with obvious gleying characteristics at a depth of 20 - 60 cm; Third, over-reclamation and insufficient return of organic materials to the field have led to a sharp reduction in the organic matter content of the black soil layer from 8% - 10% at the initial stage of reclamation to 2% - 3%, and the stability of soil aggregates has decreased, forming a sticky plate layer; In addition, the phenomenon of surface accumulation of salts caused by unreasonable irrigation systems and excessive application of chemical fertilizers has led to the emergence of a secondary salinization barrier layer in the tillage layer (0 - 30 cm).

[0003] At present, there are mainly four types of typical soil barrier layers in the black soil in Northeast China: ① plow pan layer (physically compacted type), ② white clay layer (stagnant water and sticky closed type), ③ sticky plate layer (structure degradation type), ④ saline-alkali layer (secondary salinization type). These barrier layers cause an average reduction in crop yield of 15% - 30% through mechanisms such as restricting root penetration, hindering water and gas migration, and reducing nutrient availability. In view of the formation characteristics and harm characteristics of the barrier layers in the black soil in Northeast China, it is urgent to construct a systematic reduction technology system to achieve the goals of black soil conservation and sustainable utilization. Summary of the Invention

[0004] To solve the above problems, the present invention provides a method for reducing dryland barrier layers in newly renovated black soil in Northeast China based on a soil conditioner. Using humic acid, bentonite, biochar, calcium-based minerals and straw as raw materials as an organic-inorganic composite, and then using phosphate-solubilizing bacteria agent and white rot fungus agent as a composite microbial agent, through the combined action of the two and mechanical deep plowing, the dryland barrier layers in the black soil in Northeast China are reduced.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention: Provide a soil conditioner, which is composed of an organic-inorganic composite and a composite microbial agent;

[0007] By weight, the raw materials of the organic-inorganic composite include 30 - 40 parts of humic acid, 20 - 25 parts of bentonite, 10 - 15 parts of biochar, 25 - 35 parts of calcium-based minerals and 150 - 200 parts of straw; the raw materials of the composite microbial agent include 0.5 - 1 part of phosphate-solubilizing bacteria agent and 1 - 2 parts of white rot fungus agent.

[0008] In the organic-inorganic composite of the present invention, the acidic complex of humic acid with calcium-based minerals to replace sodium ions can effectively alleviate the salinization of the barrier layer. Biochar has the functions of adsorbing heavy metal ions and serving as a proliferation carrier for composite microbial agents. Bentonite can effectively regulate the porosity of the barrier layer, and straw provides a large amount of organic matter for the barrier layer (albic horizon or clay hardpan).

[0009] In the composite microbial agent of the present invention, white rot fungi secrete various enzyme substances to degrade organic matter (straw). These enzyme substances can destroy the complex structure in the organic matter (organic matter in straw and cementitious organic matter causing soil compaction), promote its mineralization process, and cooperate with the enzymes produced by phosphate-solubilizing bacteria to further mineralize the organic phosphate degraded by white rot fungi into soluble phosphorus to supplement the organic matter and phosphorus in the barrier layer.

[0010] Preferably, by weight, the raw materials of the organic-inorganic composite include 30 parts of humic acid, 20 parts of bentonite, 10 parts of biochar, 30 parts of calcium-based mineral, and 200 parts of straw; the raw materials of the composite microbial agent include 1 part of phosphate-solubilizing bacteria and 2 parts of white rot fungi.

[0011] Preferably, the calcium-based mineral includes gypsum powder.

[0012] The second technical solution of the present invention: provides a preparation method of the above soil conditioner, including the following steps: pulverize the straw and mix it with humic acid, bentonite, biochar, and calcium-based mineral to obtain the organic-inorganic composite, and mix it evenly with the composite microbial agent composed of phosphate-solubilizing bacteria agent and white rot fungi agent to obtain the soil conditioner.

[0013] Preferably, the degree of pulverization of the straw is that the particle size does not exceed 1 cm.

[0014] The third technical solution of the present invention: provides a method for reducing the dryland barrier layer in the new renovation of the Northeast black soil based on the soil conditioner. First, apply the above soil conditioner on the ground surface and cooperate with mechanical deep loosening to complete the reduction of the dryland barrier layer.

[0015] Preferably, the application rate of the soil conditioner is 7 - 9 tons / hectare.

[0016] Preferably, the operation depth of the mechanical deep loosening is 40 - 50 cm.

[0017] Preferably, the mechanical deep loosening is completed before the freeze-thaw period.

[0018] Completing the mechanical deep loosening operation before the freeze-thaw period can utilize the natural freeze-thaw effect to further break up the soil and improve the soil porosity.

[0019] The beneficial technical effects of the present invention are as follows:

[0020] The raw materials of the soil conditioner provided by the present invention are all common and inexpensive raw materials, and the preparation steps are simple without complex processes. Through the technical path of combining physical improvement and biological improvement, the present invention realizes the reduction of the barrier layer and innovatively constructs a channel for the resource utilization of straw, which can effectively alleviate the environmental pollution problems caused by traditional straw burning. The method has the characteristics of low raw material cost, simple preparation process, convenient and efficient operation, etc. It has been verified by practice that the improvement effect on the dryland barrier layer is remarkable, and it has good ecological benefits and popularization and application value. Specific Embodiments

[0021] Soil body configuration refers to the regular combination and orderly arrangement of each soil genetic horizon, also known as soil profile configuration, which is the most important feature of the soil profile. A soil profile refers to the vertical soil profile from the ground downwards, that is, a complete vertical soil layer sequence, which is formed by the leaching, deposition, migration and transformation of substances during the soil formation process. Different types of soils have different morphological soil profiles. The soil profile can represent the external characteristics of the soil, including several genetic horizons, color, texture, structure, neoformations, etc. During the soil formation process, due to the migration and transformation of substances, the soil differentiates into a series of horizons with different compositions, properties and morphologies, called genetic horizons. The sequence and change of the genetic horizons reflect the soil formation process and soil properties. Soil body configurations are divided into 5 types, namely thin layer type, clayey cushion type, homogeneous type, interlayer type, lime concretion black soil type; and are divided into 16 configurations according to the position where the barrier layer appears.

[0022] The soil body configuration of the Northeast black soil is mainly homogeneous type, with the following characteristics:

[0023] Deep humus layer: The thickness of the humus layer of the Northeast black soil (such as typical black soil and chernozem) usually reaches 30 - 100 cm, and the texture of the upper and lower layers is uniform without obvious mutation horizons;

[0024] Texture uniformity: The clay content and color (black or dark brown) in the soil profile are distributed relatively evenly, without obvious interlayers or texture mutations, showing a "homogenized" characteristic as a whole;

[0025] Influence of parent material: It mostly develops on loess-like parent material, and the sediments are mixed sufficiently during the aeolian or alluvial process, resulting in unclear stratification.

[0026] According to the definition in the "Dictionary of Agriculture", various soil layers with poor physical and chemical properties and hindering plant growth existing in the soil body are collectively called barrier layers. The barrier effects and their degrees on plant growth vary depending on their occurrence horizons and material compositions. Common barrier layers include: clay pan layer, iron pan layer, lime concretion layer, gravel layer, salt accumulation layer, gypsum layer, albic horizon, albic soil layer, podzolized horizon, gley horizon, frozen soil layer, etc., and their barrier characteristics are different.

[0027] The common soil barrier layers in the black soil region of Northeast China and their characteristics are as follows:

[0028] 1. Plow pan (tillage compacted layer)

[0029] Formation reason: Long-term mechanical tillage (such as plowing and rotary tillage) leads to the compaction of soil particles, forming a hard layer with high compactness and low porosity;

[0030] Distribution depth: Usually located below the tillage layer (about 15 - 30 cm);

[0031] Influence: Hinders the downward growth of roots, limits the absorption of deep-layer water and nutrients by crops; reduces soil permeability and aeration, and is prone to surface runoff or waterlogging.

[0032] 2. Albic horizon (albic soil barrier layer)

[0033] Formation reason: Long-term stagnant water or seasonal waterlogging leads to the leaching and loss of iron and manganese oxides, and the residual silicon and aluminum form a grayish-white compact soil layer;

[0034] Distribution depth: Mostly appears at a depth of 20 - 50 cm, commonly found in low-lying areas or albic soil regions;

[0035] Influence: The soil is compacted and infertile, with low organic matter content; poor water permeability, prone to causing hypoxia of crop roots and waterlogging.

[0036] 3. Clay pan (heavy clay barrier layer)

[0037] Formation reason: High clay content in soil parent material or long-term leaching leads to the enrichment of clay in the lower layer;

[0038] Distribution depth: Mostly below 30 - 60 cm;

[0039] Influence: High clay content, the soil is compact, with poor water and air permeability; hinders root development, and is prone to forming a stagnant water layer.

[0040] 4. Saline-alkali layer (salinization barrier layer)

[0041] Formation reason: High groundwater level, strong evaporation or improper irrigation lead to the surface accumulation of salts;

[0042] Distribution depth: At the surface or in the shallow layer (0 - 30 cm);

[0043] Influence: The accumulation of salts (such as Na + , Cl - ) inhibits crop growth, resulting in soil compaction.

[0044] In view of the common soil barrier layers in the black soil region of Northeast China described above, the present invention specifically designs a soil conditioner. The provided soil conditioner can increase the organic matter content in the albic horizon or clay pan layer, alleviate soil salinization, and increase the content of available calcium (calcium-based minerals) and phosphorus (white rot fungi combined with phosphorus-solubilizing bacteria) in the soil. Further combined with mechanical deep loosening, the barrier layer can be effectively reduced, making the improved soil more conducive to crop growth.

[0045] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention. It should be understood that the terms used in the present invention are only for describing specific implementation modes and are not used to limit the present invention.

[0046] It should be noted that the aspects not described in detail in the present invention are all conventional operation means in the art and are not the focus of the present invention.

[0047] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0048] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention.

[0049] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0050] Unless otherwise specified, "parts" in the embodiments of the present invention all refer to "parts by mass".

[0051] The phosphorus-solubilizing bacteria agent used in the examples and comparative examples of the present invention is a commercially available product, and the effective viable count is 1×10 10 CFU / g.

[0052] The white rot fungi agent used in the examples and comparative examples of the present invention is a commercially available product, and the effective viable count is 5×10 9 CFU / g.

[0053] The humic acid, bentonite, biochar, and gypsum powder used in the examples and comparative examples of the present invention are all commercially available products.

[0054] Example 1

[0055] Preparation of soil conditioner:

[0056] (1) Crush and process the dry corn straw into segments with a particle size not exceeding 1 cm, and set aside.

[0057] (2) Weigh each raw material according to the weight ratio of 200 parts of corn straw segments, 30 parts of humic acid, 20 parts of bentonite, 10 parts of biochar, 30 parts of gypsum powder, 1 part of phosphate-solubilizing bacteria agent, and 2 parts of white rot fungus agent. Add all the raw materials to a blender and stir evenly to obtain the soil conditioner.

[0058] Example 2

[0059] Preparation of soil conditioner:

[0060] (1) Crush and process the dry corn straw into segments with a particle size not exceeding 1 cm, and set aside.

[0061] (2) Weigh each raw material according to the weight ratio of 150 parts of corn straw segments, 40 parts of humic acid, 22 parts of bentonite, 12 parts of biochar, 35 parts of gypsum powder, 0.5 part of phosphate-solubilizing bacteria agent, and 1 part of white rot fungus agent. Add all the raw materials to a blender and stir evenly to obtain the soil conditioner.

[0062] Example 3

[0063] Preparation of soil conditioner:

[0064] (1) Crush and process the dry corn straw into segments with a particle size not exceeding 1 cm, and set aside.

[0065] (2) Weigh each raw material according to the weight ratio of 180 parts of corn straw segments, 38 parts of humic acid, 25 parts of bentonite, 15 parts of biochar, 25 parts of gypsum powder, 1 part of phosphate-solubilizing bacteria agent, and 2 parts of white rot fungus agent. Add all the raw materials to a blender and stir evenly to obtain the soil conditioner.

[0066] Comparative Example 1

[0067] Preparation of soil conditioner:

[0068] Compared with Example 1, the difference is only that the addition of the phosphate-solubilizing bacteria agent and the white rot fungus agent is omitted.

[0069] Comparative Example 2

[0070] Preparation of soil conditioner:

[0071] Compared with Example 1, the difference is only that the phosphate-solubilizing bacteria agent is replaced with an equal mass of white rot fungus agent.

[0072] Comparative Example 3

[0073] Preparation of soil conditioner:

[0074] Compared with Example 1, the difference is only that the white rot fungal agent is replaced with an equal mass of phosphate-solubilizing bacterial agent.

[0075] The soil conditioner prepared in Application Examples 1-3 and Comparative Examples 1-3 was used to reduce the soil barrier layer of dry land in the black soil of Northeast China, and the reduction effect was verified.

[0076] Before the freeze-thaw period, each group of soil conditioners was surface-applied at a rate of 7 tons per hectare on the same plot. The non-application of soil conditioner was used as the blank control group. Then, mechanical subsoiling with an operation depth of 40-50 cm was carried out to complete the reduction operation. The physical and chemical properties of each plot were measured before applying the soil conditioner and before planting in the coming year to investigate the effect of the reduction method of the present invention.

[0077] (1) Content of soil dissolved organic carbon (DOC):

[0078] The sampling depth was 40 cm. Weighed 20.00 g of fresh soil sample passing through a 2 mm sieve and placed it in a 200 mL plastic bottle, added 100 mL of distilled water, oscillated on a reciprocating oscillator for 30 min (280 r / min), transferred the soil extract to a centrifuge tube and centrifuged for 20 min (4000 r / min). The supernatant after centrifugation was vacuum filtered through a 0.45 μm microporous filter membrane, and inorganic carbon was removed by acidification treatment. The DOC content in the soil was measured by a TOC automatic analyzer, and the DOC content in the soil was calculated according to the measurement results. The results are shown in Table 1.

[0079] (2) Soil pH value by potentiometry:

[0080] The sampling depth was 10 cm. Weighed 10.00 g (accurate to 0.01 g) of air-dried soil sample passing through a 2 mm sieve, placed it in a 50 mL tall-form beaker, added 25 mL of 0.01 mol / L calcium chloride solution, stirred with a glass rod for 1 min to fully disperse the soil mass, then left it for half an hour. After calibrating the instrument, the pH value of the extract was measured. The measurement results are shown in Table 1.

[0081] (3) Soil bulk density:

[0082] The soil bulk density was measured by the core method. The measurement results are shown in Table 1.

[0083] (4) Determination of available phosphorus content in soil:

[0084] The sampling depth was 30 cm. The content of available phosphorus in the soil was measured by the sodium bicarbonate method. The measurement results are shown in Table 1.

[0085] Table 1 Measurement results of physical and chemical properties of each group of soil samples

[0086]

[0087]

[0088] It can be seen from the data in Table 1 that adding the soil conditioner provided by the present invention can effectively increase the contents of DOC and available phosphorus in the soil, and reduce the pH value and bulk density of the soil.

[0089] The soil conditioners without inoculants and with only phosphate-solubilizing bacteria have little effect on increasing the DOC content in the soil. The soil conditioner of the present invention has a significant increase in the DOC content. The effect of the soil conditioner with only white rot fungi is not as good as that of the compound of phosphate-solubilizing bacteria and white rot fungi.

[0090] The amount of reduction of the soil pH value by each group of soil conditioners is mainly related to the addition amounts of humic acid and gypsum powder in the raw materials.

[0091] The soil after reduction in Example 1 group is the loosest, and the effects of using single inoculants or no inoculants are slightly reduced.

[0092] Using the compound of phosphate-solubilizing bacteria and white rot fungi can significantly increase the content of available phosphorus in the soil. The effect of only using phosphate-solubilizing bacteria is slightly inferior, indicating that phosphate-solubilizing bacteria and white rot fungi can synergistically increase the content of available phosphorus in the soil (the reason is mainly attributed to the preliminary destruction of organic matter by white rot fungi, releasing more organic phosphates that can be transformed by phosphate-solubilizing bacteria).

[0093] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A soil conditioner, characterized in that, It is composed of an organic-inorganic composite and a compound microbial inoculum; By weight, the raw materials of the organic-inorganic composite include 30-40 parts of humic acid, 20-25 parts of bentonite, 10-15 parts of biochar, 25-35 parts of calcium-based mineral, and 150-200 parts of straw; the raw materials of the compound microbial inoculum include 0.5-1 part of phosphate-solubilizing bacteria inoculum and 1-2 parts of white rot fungus inoculum.

2. The soil conditioner according to claim 1, characterized in that, By weight, the raw materials of the organic-inorganic composite include 30 parts of humic acid, 20 parts of bentonite, 10 parts of biochar, 30 parts of calcium-based mineral, and 200 parts of straw; the raw materials of the compound microbial inoculum include 1 part of phosphate-solubilizing bacteria and 2 parts of white rot fungus.

3. The soil conditioner according to claim 1, characterized in that, The calcium-based mineral includes gypsum powder.

4. A method for preparing the soil conditioner according to any one of claims 1 to 3, characterized in that, It includes the following steps: After crushing the straw, it is combined with humic acid, bentonite, biochar, and calcium-based mineral to obtain the organic-inorganic composite, and then mixed evenly with the compound microbial inoculum composed of phosphate-solubilizing bacteria inoculum and white rot fungus inoculum to obtain the soil conditioner.

5. The preparation method of the soil conditioner according to claim 4, wherein, The degree of straw crushing is that the particle size does not exceed 1 cm.

6. A new method for reducing the obstacle layer in newly reclaimed dry land of the Northeast black soil region based on soil conditioner, characterized in that, First, apply the soil conditioner according to any one of claims 1 to 3 on the ground surface, and cooperate with mechanical deep loosening to complete the reduction of the dryland obstacle layer.

7. The method for reducing the barrier layer of newly reclaimed dry land in the Northeast black soil area based on the soil conditioner according to claim 6, characterized in that The application rate of the soil conditioner is 7-9 tons per hectare.

8. The method for reducing the obstacle layer of newly renovated dry land in Northeast black soil based on soil conditioner according to claim 6, characterized in that, The operation depth of the mechanical deep loosening is 40-50 cm.

9. The method for reducing the obstacle layer of newly renovated dry land in Northeast black soil based on soil conditioner according to claim 6, characterized in that The mechanical deep loosening is completed before the freeze-thaw period.

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