Soil phosphorus improvement method

Abstract

The invention relates to the technical field of soil phosphorus improvement, in particular to a soil phosphorus improvement method, which comprises the following steps: collecting soil samples from a plurality of sampling points in a Chinese fir forest, and detecting the initial available phosphorus content and pH value of soil; adding different phosphate fertilizers into the soil with different available phosphorus contents; mixing the composite modifier solution with porous carbon to obtain modified porous carbon, and scattering the modified porous carbon on the fertilized soil to obtain improved soil; repeatedly detecting the improved soil every month within half a year, and performing corresponding treatment; after half a year, green manure plants are planted under the cunninghamia lanceolata forest, cradling is conducted after the green manure plants grow to the full-bloom stage, and the green manure plants are covered and returned to the forest or composted and returned to the forest. According to the soil phosphorus improvement method adopting the steps, different types of phosphate fertilizers are selected in a targeted mode, the dosage of the phosphate fertilizers is controlled, the precise fertilization strategy is matched with subsequent soil improvement measures, the effectiveness and the utilization rate of phosphorus in soil are greatly improved, and waste of the phosphate fertilizers is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of soil phosphorus improvement, and in particular to a soil phosphorus improvement method. Background Art

[0002] Chinese fir is a very valuable fast-growing timber species in my country, and occupies an important position in the forestry industry, especially in wood production. However, due to the afforestation of pure Chinese fir forests and multiple generations of continuous planting, the soil quality has been declining, among which the problem of soil phosphorus deficiency is particularly prominent. Phosphorus in the soil is an indispensable key nutrient element for the growth of Chinese fir, and plays a decisive role in the physiological processes of Chinese fir such as cell division, photosynthesis, and energy metabolism. The effectiveness of phosphorus in the soil is not static, but is affected by a combination of many complex factors. Soil pH is an extremely important part of it. In an acidic soil environment, the content of iron and aluminum oxides in the soil is high. These substances easily react chemically with phosphate ions to form insoluble phosphates, which leads to a significant reduction in the effective phosphorus content in the soil.

[0003] In addition, the content of soil organic matter also has a significant impact on the effectiveness of phosphorus. Soil rich in organic matter can provide more adsorption sites for phosphorus and reduce the fixation of phosphorus. At the same time, organic matter will produce organic acids during the decomposition process. These organic acids can dissolve the insoluble phosphorus in the soil and improve the effectiveness of phosphorus. However, in the long-term management of Chinese fir forests, due to unreasonable management measures such as over-logging, destruction of understory vegetation, and multiple generations of continuous planting, the content of soil organic matter has gradually decreased, further exacerbating the problem of soil phosphorus deficiency.

[0004] In the past, the method of simply relying on the application of phosphate fertilizers not only resulted in a low utilization rate of phosphate fertilizers, but also caused a large amount of phosphate fertilizers to be fixed in the soil and unable to be effectively absorbed and utilized by Chinese fir, resulting in a huge waste of resources and possibly causing a series of environmental problems, such as eutrophication of water bodies. At the same time, traditional methods often ignore the complexity of the soil ecosystem and fail to fundamentally improve the physical and chemical properties of the soil and the structure of the microbial community, resulting in incomplete soil improvement effects and difficulty in achieving long-term productivity maintenance and sustainable management of Chinese fir forests. Summary of the invention

[0005] The purpose of the present invention is to provide a soil phosphorus improvement method to increase the soil phosphorus content and effectiveness, promote the growth of Chinese fir, and increase the productivity and wood stock of Chinese fir.

[0006] To achieve the above object, the present invention provides a method for improving soil phosphorus, comprising the following steps: S1. Collect soil samples at multiple sampling points in the fir forest, remove the gravel and roots in the soil, and test the initial available phosphorus content and pH value of the soil at different depths; S2. According to the results obtained in S1, a highly water-soluble phosphate fertilizer is added to the soil with low available phosphorus content, a calcium-magnesium phosphate fertilizer is added to the soil with medium available phosphorus content, and a slow-release phosphate fertilizer is added to the soil with high available phosphorus content; S3, dissolving the composite modifier in water to prepare a composite modifier solution, mixing the composite modifier solution with porous carbon to obtain modified porous carbon, and spreading the modified porous carbon on the soil after fertilization in S2 to obtain improved soil; S4, repeat step S1 for the improved soil in S3 every month within half a year, and select step S2 or S3 according to the result; S5. Plant green manure plants under the fir forest half a year later, cut them when they reach the flowering period, and return them to the forest after mulching or composting.

[0007] Preferably, in S1, the number of sampling points is 100-200 / hectare, and the sampling points are evenly distributed in the Chinese fir forest.

[0008] Preferably, in S2, the low available phosphorus content is 3-10 mg / kg, and the amount of high water-soluble phosphate fertilizer added is 100-200 kg / hectare.

[0009] In the present invention, the water-soluble phosphate fertilizer has strong water solubility, can be quickly dissolved in water, quickly releases phosphate ions, and quickly diffuses into the soil in the form of ions.

[0010] Preferably, in S2, the available phosphorus content is 10-30 mg / kg, and the amount of calcium magnesium phosphate added is 80-150 kg / hectare.

[0011] In the present invention, the calcium magnesium phosphate fertilizer needs to be gradually dissolved and release phosphorus under the acidic conditions in the soil or under the action of microorganisms.

[0012] Preferably, in S2, the high available phosphorus content is 30-100 mg / kg, and the amount of slow-release phosphate fertilizer added is 30-80 kg / hectare.

[0013] In the present invention, the slow-release phosphate fertilizer has slow-release and long-lasting effects, and one-time fertilization can continuously provide phosphorus for a long time.

[0014] Preferably, in S3, the composite improver includes one or more of a pH regulator, phosphate-solubilizing bacteria, starch, chitosan, polyethylene oxide, humic acid and amino acids.

[0015] In the present invention, starch, chitosan and polyethylene oxide form a stable flocculation structure in the soil, thereby increasing the water and fertilizer retention capacity of the soil.

[0016] Preferably, in S3, the porous carbon includes one or more of activated carbon, bamboo fiber porous carbon and onion porous carbon.

[0017] In the present invention, the porous carbon can also improve the air permeability and water permeability of the soil and promote the activities of soil microorganisms.

[0018] Preferably, in S3, the mass ratio of the modified porous carbon to the composite modifier is 1:0.5-2, and the added amount of the composite modifier is 500-3000 kg / hectare.

[0019] Preferably, in S5, the green manure plants include one or more of astragalus, vetch, alfalfa, sesbania, chrysanthemum and lupine.

[0020] Preferably, in S5, litter from the Chinese fir forest is added during composting.

[0021] Therefore, the present invention adopts a soil phosphorus improvement method of the above steps, and its beneficial effects are: 1. The improvement method provided by the present invention can accurately detect the initial effective phosphorus content in the soil, selectively select different types of phosphate fertilizers and control their dosage, and the precise fertilization strategy and subsequent soil improvement measures cooperate with each other, thereby greatly improving the effectiveness and utilization rate of phosphorus in the soil and reducing the waste of phosphate fertilizers; 2. In the composite improver used in the present invention, the pH regulator can be adjusted according to the pH value of the soil to create a suitable living environment for microorganisms such as phosphate-solubilizing bacteria. The phosphate-solubilizing bacteria can secrete organic acids and phosphatases to convert the insoluble phosphorus in the soil into effective phosphorus that can be absorbed by plants. The remaining components can improve the soil structure, increase the soil's water and fertilizer retention capacity, provide nutrition and habitat for phosphate-solubilizing bacteria, and promote their growth and reproduction; 3. The present invention improves the physical and chemical properties and microbial community structure of the soil through the synergistic effect of porous carbon and composite modifier, improves the solubility, desorption and activation capacity of soil phosphorus, and further improves the effectiveness of soil phosphorus; 4. The present invention mows the green manure plants during their blooming period and returns them to the forest after covering or composting them. This can not only increase the soil organic matter content and improve the soil structure, but also provide the soil with nitrogen, phosphorus, potassium and other nutrients. It cooperates with the previous measures such as fertilization regulation and modified porous carbon addition to form a sustainable soil phosphorus improvement system, which is beneficial to the long-term stable development of the Chinese fir forest.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a schematic diagram of a process for improving soil phosphorus. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0025] Example 1 like Figure 1 As shown, the present invention provides a method for improving soil phosphorus, comprising the following steps: S1. Collect soil samples at multiple sampling points in the fir forest. The number of sampling points is 200 / hectare, and the sampling points are evenly distributed in the fir forest. Remove the gravel and roots in the soil, and test the initial available phosphorus content and pH value of the soil surface, middle layer (10cm) and bottom layer (30cm). The average initial available phosphorus content is 5mg / kg and the pH value is 5.

[0026] S2. According to the result obtained in S1, the soil of the fir forest has low available phosphorus content. Highly water-soluble phosphate fertilizer is added to the soil with low available phosphorus content, and the amount of the highly water-soluble phosphate fertilizer added is 200 kg / hectare.

[0027] S3. Dissolve the composite modifier (the mass ratio of pH regulator, phosphate-solubilizing bacteria, starch and humic acid is 6:1.5:1:2) in water to prepare a composite modifier solution, mix the composite modifier solution with activated carbon to obtain modified porous carbon, and sprinkle the modified porous carbon on the soil after fertilization in S2. The mass ratio of the modified porous carbon to the composite modifier is 1:0.5, and the amount of the composite modifier added is 3000 kg / hectare to obtain improved soil.

[0028] S4. Repeat step S1 for the improved soil in S3 every month within half a year. When the soil has a low or medium available phosphorus content, perform steps S2 and S3. When the soil has a high available phosphorus content, perform step S3.

[0029] S5. Plant green manure plants (Chinese astragalus and alfalfa) under the fir forest half a year later. Mow the green manure plants when they reach the flowering stage and return them to the forest after mulching or add them to the litter compost in the fir forest.

[0030] Example 2 A method for improving soil phosphorus comprises the following steps: S1. Collect soil samples at multiple sampling points in the fir forest. The number of sampling points is 200 / hectare, and the sampling points are evenly distributed in the fir forest. Remove the gravel and roots in the soil, and test the initial available phosphorus content and pH value of the soil surface, middle layer (10cm) and bottom layer (30cm). The average initial available phosphorus content is 23mg / kg, and the pH value is 6.5.

[0031] S2. According to the result obtained in S1, the soil of the Chinese fir forest in this embodiment has a medium effective phosphorus content, and 100 kg / hectare of calcium magnesium phosphate fertilizer is added to the soil with a medium effective phosphorus content.

[0032] S3. Dissolve the composite modifier (the mass ratio of pH regulator, phosphate-solubilizing bacteria, chitosan and amino acid is 4:1.5:1:3) in water to prepare a composite modifier solution, mix the composite modifier solution with bamboo fiber porous carbon to obtain modified porous carbon, the mass ratio of modified porous carbon to the composite modifier is 1:1, the amount of the composite modifier added is 2000 kg / hectare, and sprinkle the modified porous carbon on the soil after fertilization in S2 to obtain improved soil.

[0033] S4. Repeat step S1 for the improved soil in S3 every month within half a year. When the soil has a medium available phosphorus content, perform steps S2 and S3. When the soil has a high available phosphorus content, perform step S3.

[0034] S5. Plant green manure plants (potato, radish and lupine) under the fir forest half a year later. Cut the green manure plants when they reach the flowering stage and return them to the forest after mulching or add them to the litter in the fir forest for composting and then return them to the forest.

[0035] Example 3 A method for improving soil phosphorus comprises the following steps: S1. Collect soil samples at multiple sampling points in the fir forest. The number of sampling points is 200 / hectare, and the sampling points are evenly distributed in the fir forest. Remove the gravel and roots in the soil, and test the initial available phosphorus content and pH value of the soil surface, middle layer (10cm) and bottom layer (30cm). The average initial available phosphorus content is 40mg / kg and the pH value is 7.

[0036] S2. According to the result obtained in S1, the fir forest in this embodiment has soil with a high available phosphorus content. Slow-release phosphate fertilizer is added to the soil with a high available phosphorus content. The amount of slow-release phosphate fertilizer added is 50 kg / hectare.

[0037] S3. Dissolve the composite modifier (the mass ratio of pH regulator, phosphate-solubilizing bacteria, polyethylene oxide and amino acid is 3:1.5:2:3) in water to prepare a composite modifier solution, mix the composite modifier solution with onion porous carbon to obtain modified porous carbon, the mass ratio of the modified porous carbon to the composite modifier is 1:2, the amount of the composite modifier added is 2500 kg / hectare, and sprinkle the modified porous carbon on the soil after fertilization in S2 to obtain improved soil.

[0038] S4. Repeat step S1 for the improved soil in S3 every month within half a year, and perform step S3 when the soil has a high available phosphorus content.

[0039] S5. Plant green manure plants (sesbania and alfalfa) under the fir forest half a year later. Mow the green manure plants when they reach the flowering stage and return them to the forest after mulching or add them to the litter compost in the fir forest.

[0040] Comparative Example 1 A method for improving soil phosphorus comprises the following steps: S1. Collect soil samples at multiple sampling points in the fir forest. The number of sampling points is 200 / hectare, and the sampling points are evenly distributed in the fir forest. Remove the gravel and roots in the soil, and test the initial available phosphorus content and pH value of the soil surface, middle layer (10cm) and bottom layer (30cm). The average initial available phosphorus content is 5mg / kg, and the pH value is 4.5.

[0041] S2. According to the results obtained in S1, the soil in this comparative example has a low available phosphorus content. A highly water-soluble phosphate fertilizer is added to the soil with a low available phosphorus content, and the amount of the highly water-soluble phosphate fertilizer added is 200 kg / hectare to obtain improved soil.

[0042] S3. Repeat step S1 for the improved soil in S2 every month within half a year. If the soil has a low or medium available phosphorus content, perform step S2. If the soil has a high available phosphorus content, do not perform any treatment.

[0043] S4. Plant green manure plants (Chinese astragalus and alfalfa) under the fir forest half a year later. When the green manure plants grow to the flowering stage, cut them and return them to the forest after mulching or add them to the litter in the fir forest for composting and then return them to the forest.

[0044] Test Example 1 The average value of the effective phosphorus content of the improved soil in Examples 1-3 and Comparative Example 1 was tested, and the results are shown in Table 1.

[0045] Table 1. Average data table of available phosphorus content in soil in Examples 1-3 and Comparative Example 1

[0046] As can be seen from Table 1, in Examples 1-3, by adding modified porous carbon, the effective phosphorus content in the soil is maintained in a stable range. Through the synergistic effect of porous carbon and the composite modifier, the physical and chemical properties and microbial community structure of the soil are improved, the solubility, desorption and activation capabilities of soil phosphorus are improved, and the effectiveness of soil phosphorus is further improved.

[0047] Therefore, the present invention adopts a soil phosphorus improvement method of the above steps, specifically selects different types of phosphorus fertilizers and controls their dosage, and the precise fertilization strategy cooperates with subsequent soil improvement measures, which greatly improves the effectiveness and utilization rate of phosphorus in the soil and reduces the waste of phosphorus fertilizers.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for improving soil phosphorus, characterized in that: The following steps are included: S1. Collect soil samples at multiple sampling points in the fir forest, remove the gravel and roots in the soil, and test the initial available phosphorus content and pH value of the soil at different depths; S2. According to the results obtained in S1, a highly water-soluble phosphate fertilizer is added to the soil of the Chinese fir forest with low available phosphorus content, a calcium-magnesium phosphate fertilizer is added to the soil of the Chinese fir forest with medium available phosphorus content, and a slow-release phosphate fertilizer is added to the soil of the Chinese fir forest with high available phosphorus content; S3, dissolving the composite modifier in water to prepare a composite modifier solution, mixing the composite modifier solution with porous carbon to obtain modified porous carbon, and spreading the modified porous carbon on the soil after fertilization in S2 to obtain improved soil; S4, repeat step S1 for the improved soil in S3 every month within half a year, and select step S2 or S3 according to the result; S5. Plant green manure plants under the fir forest half a year later, cut them when they reach the flowering period, and return them to the forest after mulching or composting.

2. A method for improving soil phosphorus according to claim 1, characterized in that: In S1, the number of sampling points was 100–200 / ha, and the sampling points were evenly distributed in the fir forest.

3. A soil phosphorus improvement method according to claim 1, characterized in that: In S2, the low available phosphorus content is 3-10 mg / kg, and the amount of high water-soluble phosphorus fertilizer added is 100-200 kg / hectare.

4. The method for improving soil phosphorus according to claim 1, characterized in that: In S2, the available phosphorus content is 10-30 mg / kg, and the amount of calcium magnesium phosphate fertilizer added is 80-150 kg / hectare.

5. The method for improving soil phosphorus according to claim 1, characterized in that: In S2, the high available phosphorus content is 30-100 mg / kg, and the amount of slow-release phosphorus fertilizer added is 30-80 kg / hectare.

6. The method for improving soil phosphorus according to claim 1, characterized in that: In S3, the composite improver includes one or more of a pH regulator, phosphate-solubilizing bacteria, starch, chitosan, polyethylene oxide, humic acid and amino acids.

7. The method for improving soil phosphorus according to claim 1, characterized in that: In S3, the porous carbon includes one or more of activated carbon, bamboo fiber porous carbon and onion porous carbon.

8. The method for improving soil phosphorus according to claim 1, characterized in that: In S3, the mass ratio of the modified porous carbon to the composite modifier is 1:0.5-2, and the addition amount of the composite modifier is 500-3000 kg / hectare.

9. The method for improving soil phosphorus according to claim 1, characterized in that: In S5, the green manure plants include one or more of astragalus, vetch, alfalfa, sesbania, chrysanthemum and lupine.

10. The method for improving soil phosphorus according to claim 1, characterized in that: In S5, litter from the fir forest was added during composting.

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