Method for recarburizing and expanding capacity of soil nutrient reservoir of non-grain cultivated land

Abstract

The invention relates to the technical field of cultivated land quality improvement, and discloses a non-grain cultivated land soil nutrient library recarburization and capacity expansion method which comprises the following steps: firstly, deep ploughing is performed, then an organic-inorganic mixed fertilizer and a special complex microbial inoculant are applied, and the organic-inorganic mixed fertilizer comprises completely decomposed cow dung, woody peat, an inorganic nitrogen fertilizer, potassium fulvic acid and an inorganic phosphate fertilizer; the special composite microbial inoculant comprises arbuscular mycorrhizal fungi and bacillus mucilaginosus; the organic-inorganic mixed fertilizer and the special complex microbial inoculant are uniformly distributed in soil of a plough layer, microorganisms in the special complex microbial inoculant can decompose organic fertilizer in the organic-inorganic mixed fertilizer, fix nutrients, supplement a soil nutrient library and increase the content of organic carbon in the soil, mycorrhiza of arbuscular mycorrhizal fungi can further fix the content of organic carbon in the soil, and the content of organic carbon in the soil is increased. The bacillus mucilaginosus can assist the survival of arbuscular mycorrhizal fungi and promote the growth of mycorrhiza of the arbuscular mycorrhizal fungi; by means of the method, the soil quality of the non-grain cultivated land is rapidly improved, and the grain yield is remarkably increased.

Description

Technical Field

[0001] The present invention relates to the technical field of improving the quality of cultivated land, and in particular to a method for increasing the carbon content and expanding the soil nutrient pool of "non-grain" cultivated land. Background Art

[0003] Due to the long-term planting of seedlings, flowers, fruits, bamboo, tea and other perennial cash crops, the tillage layer of some "non-grain" cultivated land has been damaged to varying degrees. There are major soil obstacles such as damaged soil structure, unbalanced nutrients, loss of microbial functions, and poor crop adaptability, making it difficult to ensure normal grain production. Therefore, the rapid reconstruction of the tillage layer, improvement of soil structure and improvement of soil fertility of "non-grain" cultivated land have become key issues that need to be solved urgently. It is urgent to develop efficient and comprehensive technologies for rapid reconstruction of the soil tillage layer and improvement of fertility, so as to truly realize "storing grain in the land and storing grain in technology" and provide important technical support for ensuring food security in our province. Summary of the invention

[0004] In order to solve the above-mentioned existing problems, the present invention discloses a method for increasing carbon and expanding the soil nutrient pool of "non-grain" cultivated land. For the "non-grain" cultivated land in the south, the soil of the "non-grain" cultivated land is first deeply plowed, and then organic-inorganic mixed fertilizer and special composite bacterial agent are applied to make the organic-inorganic mixed fertilizer and the special composite bacterial agent evenly distributed in the tillage layer. The microorganisms in the special composite bacterial agent can decompose the organic fertilizer in the organic-inorganic mixed fertilizer and fix nutrients, replenish the soil nutrient pool, and increase the soil organic carbon content. The special composite bacterial agent contains arbuscular mycorrhizal fungi and mucoid Bacillus. The mycorrhiza of arbuscular mycorrhizal fungi can further fix the content of organic carbon in the soil, thereby achieving a capacity expansion effect. Mucoid Bacillus can assist the survival of arbuscular mycorrhizal fungi and promote the growth of their mycorrhiza. Under the method of the present invention, the soil quality of the "non-grain" cultivated land is rapidly improved, and the grain yield is significantly increased.

[0005] The carbon increase and expansion of the soil nutrient pool have the following meanings: supplementing the missing nutrients in the "non-grain" cultivated land soil, such as organic matter, water-soluble organic carbon, quick-acting nitrogen and quick-acting phosphorus, which is reflected in the results as increasing the content of corresponding soil physical and chemical indicators; increasing the content of nutrients that can be retained in the "non-grain" cultivated land soil, and promoting the recycling and regeneration of soil nutrients, such as increasing the content of microbial biomass carbon and microbial biomass nitrogen in the soil, which is reflected in the results as maintaining the content of corresponding soil physical and chemical indicators at a high level.

[0006] On the one hand, the present invention provides a method for increasing carbon and expanding the soil nutrient pool of "non-grain" cultivated land in the south, comprising the steps of: S1, tilling, turning down about 20-30cm of soil, repeating 2-6 times; S2, applying organic-inorganic mixed fertilizer and special composite bacterial agent on the topsoil, and ploughing again according to step S1; The organic-inorganic mixed fertilizer includes fully decomposed cow dung, woody peat, inorganic nitrogen fertilizer, potassium humate and inorganic phosphorus fertilizer; the fully decomposed cow dung contains 16-20% organic matter; the woody peat contains 55-75% humic acid; the organic acid salt content of potassium humate is ≥80%; the nitrogen content of the inorganic nitrogen fertilizer is ≥15%; the phosphorus content of the inorganic phosphorus fertilizer is ≥8%; The special composite bacterial agent comprises arbuscular mycorrhizal fungi and colloid bacillus; the arbuscular mycorrhizal fungi is composed of spore mold (Rhizophgus clarus ) and Glomus natans ( Claroideoglomus etunicatum )composition.

[0007] The fully decomposed cow dung is cow dung that has been decomposed to eliminate pest eggs and pathogenic microorganisms, and contains 16-20% organic matter and a small amount of nitrogen, phosphorus and potassium. The woody peat refers to peat composed of woody plant residues, with a relative density of 0.7-1g / cm 3 , carbon content is 60-65%, humic acid content is 55-75%; the organic acid salt content of the potassium humate is ≥80%, the total organic matter content is ≥60%, and the moisture content is <5%; the nitrogen content of the inorganic nitrogen fertilizer is ≥15%; the total phosphorus content of the inorganic phosphorus fertilizer is ≥8%.

[0008] Arbuscular mycorrhiza ( Arbuscular mycorrhiza AM fungi are root symbiotic microorganisms that are ubiquitous in farmland ecosystems and can form symbiotic relationships with major crops such as rice, wheat, corn, and leguminous green manure. After infection, AM fungi can form a huge mycelium network in the soil, expand the absorption area of ​​the root system, help plants absorb nutrients, promote plant growth and development, and improve plant resistance. However, the current application of AM fungi is mostly based on indoor simulation tests, and there are still technical bottlenecks that need to be broken through in field applications. There are mainly two factors: (1) AM fungi are greatly affected by their host plants, especially in "non-grain" cultivated soils, where the original dominant AM fungal populations of crops are weakened or lost, and it is necessary to screen dominant AM fungi based on crops and soil environments.

[0009] (2) The germination and infection of AM fungi are affected by many factors, such as soil pH, organic matter, and nitrogen and phosphorus nutrient content. The nutrient deficiency in non-grain cultivated land makes it difficult to ensure the germination and infection of AM fungi.

[0010] To solve the above problems, the present invention adopts the method of organic-inorganic mixed fertilizer and special composite microbial agent. First, the present invention finds that woody peat and potassium humate can play a synergistic effect to promote the germination and infection of AM fungi in "non-grain" cultivated soil. Potassium humate can also provide potassium. On this basis, livestock and poultry manure is used as an organic carbon source and nitrogen source, and phosphate fertilizer is used as a phosphorus source. The germination and infection of AM fungi in "non-grain" cultivated soil in turn promotes the fixation of nutrients in the soil. Therefore, organic-inorganic mixed fertilizer and special composite microbial agent promote the carbon increase and expansion of the nutrient pool of "non-grain" cultivated soil in a synergistic way.

[0011] Secondly, phosphorus is an essential element for food crops, but excessive phosphorus content in the soil will have an inhibitory effect on AM fungi. Through a large number of experiments, the present invention found that only Bacillus subtilis can promote the germination and infection of AM fungi and promote mycorrhizal growth in a soil environment with a high phosphorus content. This may be because Bacillus subtilis produces related polypeptides or other substances in a soil environment with a high phosphorus content, and the substances can be used by AM fungi. The specific mechanism of action needs to be further demonstrated.

[0012] Finally, by tilling the soil and applying organic-inorganic mixed fertilizers and special compound microbial agents, the organic-inorganic mixed fertilizers and special compound microbial agents are evenly spread into the cultivated layer of soil. In each layer of the soil, AM fungi cooperate with food crops to produce mycorrhizae, which is beneficial for food crops to absorb nutrients in the "non-grain" cultivated soil on the one hand, and on the other hand, it is beneficial for the fixation and regeneration of nutrients in the "non-grain" cultivated soil.

[0013] There are many species of arbuscular mycorrhizal fungi, such as Sporangium minguigeninum ( Rhizophgus clarus ) and Glomus juveniles ( Claroideoglomus etunicatum ) are two species with different characteristics; the present invention cultivates dominant AM bacteria species by planting major food crops in a targeted manner, and two of the dominant species obtained after identification and separation have synergy or competition between the species. Through a large number of experiments, the present invention finds that the above two species can have a synergistic effect, and promote the carbon increase and expansion of the soil nutrient pool of "non-grain" cultivated land to the greatest extent, especially increase the microbial biomass carbon in the soil; and other species and combinations discovered so far cannot achieve such an effect, and even have negative effects due to competition or antagonism. Therefore, the arbuscular mycorrhizal fungi composed of Ammonium erythrorhizium and Ammonium erythrorhizium are used as the preferred embodiment of the present invention.

[0014] In some embodiments, in step S2, the ratio of the organic-inorganic mixed fertilizer to the special composite bacterial agent is 1:0.001 to 1:0.5, calculated by weight.

[0015] In some embodiments, in step S2, 50-80 kg of organic-inorganic mixed fertilizer is applied per mu of cultivated land.

[0016] In some embodiments, the organic-inorganic mixed fertilizer includes 40-60 parts of fully decomposed cow dung, 15-25 parts of woody peat, 10-15 parts of inorganic nitrogen fertilizer, 15-25 parts of potassium humate and 5-10 parts of inorganic phosphorus fertilizer, calculated by weight.

[0017] In some embodiments, the weight ratio of the Sporangiophora minguigensis to the Sporangiophora nauplii is 1:0.1-1:10.

[0018] Further preferably, the special composite bacterial agent also includes Trichoderma harzianum.

[0019] After selecting the combination of the above two preferred AM strains, it was found that although the soil nutrient content can be significantly increased within a period of time, the effect of increasing carbon and expanding the nutrient pool gradually decreased after a period of time. Through a large number of experiments, the present invention found that adding Trichoderma harzianum helps to maintain the special composite bacterial agent to maintain a high nutrient content in the soil for a long time. This may be that Trichoderma harzianum improves the plant-AM fungus interaction by affecting the corresponding biochemical process of the plant, thereby improving the soil nutrient cycle regeneration. The specific action principle needs to be further demonstrated.

[0020] In some embodiments, the special composite bacterial agent includes 2-8 parts of arbuscular mycorrhizal fungi, 1-3 parts of mucilaginous Bacillus and 1-3 parts of Trichoderma harzianum, calculated by weight.

[0021] Further preferably, the special composite bacterial agent also includes auxiliary agents, and the auxiliary agents include seaweed oligosaccharides, polyaspartic acid and polyarginine.

[0022] As above, in the face of the problem that the above two strains of bacteria cannot maintain high nutrient content in the soil for a long time, the present invention has found through a large number of experiments that another way can be adopted, that is, adding seaweed oligosaccharides, polyaspartic acid and polyarginine as adjuvants, so that the nutrient content in the soil can be stably maintained at a high level for a long time. The reason may be that plants use the above substances to change related biochemical processes, improve plant-AM fungi interactions, and thus improve soil nutrient recycling and regeneration. The specific mechanism of action needs to be further demonstrated.

[0023] In some embodiments, the special composite bacterial agent includes 2-8 parts of arbuscular mycorrhizal fungi, 1-3 parts of colloid Bacillus, 0.4-1.2 parts of seaweed oligosaccharides, 0.2-0.5 parts of polyaspartic acid and 0.7-1.5 parts of polyarginine, calculated by weight.

[0024] On the other hand, the present invention provides a composition for increasing carbon and expanding the nutrient pool of soil in "non-grain" cultivated land in the south, comprising an organic-inorganic mixed fertilizer and a special composite microbial agent, wherein the organic-inorganic mixed fertilizer comprises fully decomposed cow dung, woody peat, potassium humate and inorganic phosphate fertilizer; the fully decomposed cow dung contains 16-20% organic matter; the woody peat contains 55-75% humic acid; the organic acid salt content of potassium humate is ≥80%; the nitrogen content of the inorganic nitrogen fertilizer is ≥15%; the phosphorus content of the inorganic phosphate fertilizer is ≥8%; the special composite microbial agent comprises arbuscular mycorrhizal fungi and mucilaginous bacillus; the arbuscular mycorrhizal fungi are composed of Sporangiophora acuminata ( Rhizophgus clarus ) and Glomus natans ( Claroideoglomus etunicatum )composition.

[0025] In another aspect, the present invention provides a use of a bacterial composition for preparing a reagent for increasing carbon and expanding the nutrient pool of soil in "non-grain" cultivated land in the south, wherein the bacterial composition is composed of Sporangium minguigensis ( Rhizophgus clarus ) and Glomus natans ( Claroideoglomus etunicatum )composition.

[0026] In another aspect, the present invention provides a use of Trichoderma harzianum for preparing a reagent for prolonging the time for arbuscular mycorrhizal fungi to increase carbon and expand the nutrient pool of soil in "non-grain" cultivated land in the south, wherein the arbuscular mycorrhizal fungi are composed of Sporangium minguigensis ( Rhizophgus clarus ) and Glomus natans ( Claroideoglomus etunicatum )composition.

[0027] In another aspect, the present invention provides a composition for preparing an agent for prolonging the time for arbuscular mycorrhizal fungi to increase carbon and expand the nutrient pool of soil in "non-grain" cultivated land in the south, wherein the arbuscular mycorrhizal fungi are composed of Sporangium minguigensis ( Rhizophgus clarus ) and Glomus natans ( Claroideoglomus etunicatum ), the composition includes seaweed oligosaccharides, polyaspartic acid and polyarginine.

[0028] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The present invention discloses a method for increasing carbon and expanding the nutrient pool of soil in "non-grain" cultivated land. First, the soil of the "non-grain" cultivated land is deeply plowed, and organic-inorganic mixed fertilizer, special composite microbial agent and soil are mixed to make the organic-inorganic mixed fertilizer and the special composite microbial agent evenly distributed in the cultivated layer soil; the components in the organic-inorganic mixed fertilizer can play a synergistic effect to promote the germination and infection of arbuscular mycorrhizal fungi, and the mycorrhiza of arbuscular mycorrhizal fungi can further fix the content of organic carbon in the soil, thereby playing a capacity expansion effect. The present invention also finds that Bacillus mucilaginosus can assist arbuscular mycorrhizal fungi to survive and promote the growth of their mycorrhiza in an environment with high phosphorus content; under the method of the present invention, the soil quality of the "non-grain" cultivated land is rapidly improved (the content of organic matter, water-soluble organic carbon, available nitrogen, available phosphorus, microbial biomass carbon and microbial biomass nitrogen is significantly increased), the microbial community in the soil is reshaped, the decomposition metabolism of organic matter and nitrogen cycle are improved, and the yield of grain crops is significantly increased; 2. Based on the above method, two arbuscular mycorrhizal fungi species with synergistic effects were further selected through a large number of experiments. The combination of arbuscular mycorrhizal fungi can further significantly improve the nutrient content of "non-grain" cultivated land soil, especially increase the microbial biomass carbon and microbial biomass nitrogen content, and further increase grain production; 3. The application scope of the method of the present invention has been expanded through theoretical research and experimental verification. Based on the combination of two preferred arbuscular mycorrhizal fungal species, the further introduction of Trichoderma harzianum or the addition of seaweed oligosaccharides, polyaspartic acid and polyarginine can improve plant-fungal interactions, promote mycorrhizal growth and the recycling of soil nutrients, and maintain the soil nutrient content of "non-grain" cultivated land at a high level for a long time, which is conducive to the planting of long-cycle food crops such as winter wheat on "non-grain" cultivated land. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 : Results of determination of soil organic matter content in "non-grain" cultivated land in the south; Figure 2 : Results of determination of cation exchange capacity of soil in "non-grain" cultivated land in southern China; Figure 3 : Results of determination of soil carbon, total nitrogen, available phosphorus and available potassium in "non-grain" cultivated land in the south; Figure 4 : Results of soil bulk density measurement of “non-grain” cultivated land in the south; Figure 5 : Results of soil aggregate determination in “non-grain” cultivated land in the south; Figure 6 : Results of infrared spectroscopy determination of soil organic carbon components in "non-grain" cultivated land in southern China; Figure 7 :Analysis results of Chao index and Shannon index of soil bacterial community in "non-grain" cultivated land in southern China; Figure 8 :PcoA and UPGMA cluster analysis results of soil bacterial community structure in "non-grain" cultivated land in southern China; Fig. 9 : Results of compositional differences of soil bacterial communities at the phylum level in "non-grain" cultivated land in southern China; Fig.10 : Analysis results of soil organic matter decomposition, xenobiotic degradation, methane metabolism, nitrogen cycle and manganese cycle in "non-grain" cultivated land in southern China; Among them, CK represents a blank control group, EG1 represents a group applying chemical fertilizers, EG2 represents a group applying chemical fertilizers and organic fertilizers, and EG3 represents a group applying organic-inorganic mixed fertilizers and a special composite microbial agent, as shown in Example 6; Figure 7 and Figure 8 In the figure, red, green, blue, and purple markers represent CK, EG1, EG2, and EG3, respectively; Figure 7 In the figure, the left picture (a) shows the Chao index analysis results of the bacterial community, and the right picture (b) shows the Shannon index analysis results of the bacterial community; Figure 8 In the figure, the left picture (a) shows the PcoA cluster analysis results of the bacterial community structure, and the right picture (b) shows the UPGMA cluster analysis results of the bacterial community structure. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and specific examples, which are only used to explain the present invention and are not intended to limit the scope of the present invention. The materials, reagents, etc. used in the following examples are reagents and materials available from commercial sources unless otherwise specified. Example 1: Method for increasing carbon and expanding the soil nutrient pool of "non-grain" cultivated land

[0031] The experimental base is located at the "non-grain" soil fertility improvement and enhancement base in Wucheng District, Jinhua City, Zhejiang Province.

[0032] First, the "non-grain" arable land is plowed, and the soil is turned down to about 30cm, and repeated 4 times. The main purpose of plowing is to loosen the soil and prepare for the next step of applying organic-inorganic mixed fertilizers and special compound microbial agents. Therefore, the plowing depth can be selected according to the actual situation of the "non-grain" arable land.

[0033] Preparation of organic-inorganic mixed fertilizer: Calculated by weight, take 50 parts of high-temperature sterilized livestock and poultry manure, 20 parts of commercially available woody peat, 10 parts of commercially available inorganic nitrogen fertilizer, 20 parts of commercially available potassium humate and 10 parts of commercially available inorganic phosphate fertilizer, and mix them evenly.

[0034] The technical indicators of each component in the organic-inorganic mixed fertilizer are as follows: the fully decomposed cow dung refers to the cow dung that has been decomposed to eliminate pest eggs and pathogenic microorganisms, which contains 16-20% organic matter and a small amount of nitrogen, phosphorus and potassium; the woody peat refers to peat composed of woody plant residues, with a relative density of 0.7-1g / cm 3 , carbon content is 60-65%, humic acid content is 55-75%; the nitrogen content of the inorganic nitrogen fertilizer is ≥15%; the organic acid salt content of the potassium humate is ≥80%, the total organic matter content is ≥60%, and the moisture content is <5%; the phosphorus content of the inorganic phosphorus fertilizer is ≥8%.

[0035] Preparation of special composite microbial agent: Select "non-grain" arable land of economic forestry and fruit, collect root system and rhizosphere soil samples of main crops, mix the collected soil samples with sterilized river sand (1:1), plant wheat, white clover and alfalfa in the greenhouse to induce culture of AM fungi, pass the soil sample through a 20-mesh sieve, and use the wet sieving decantation method to separate and extract spores to obtain AM fungi; calculate by weight, take 8 parts of cultured AM fungi and 2 parts of commercially available Bacillus subtilis, mix them evenly, and the number of viable bacteria (cfu) is >100 million / g.

[0036] For each mu of "non-grain" arable land, apply 50-80 kg of organic-inorganic mixed fertilizer and 15 kg of special compound microbial agent; the application method is: evenly mix the organic-inorganic mixed fertilizer and the special compound microbial agent, evenly spread them on the topsoil, and then plow down 20-30 cm. The plowing depth can be selected according to the actual situation of the "non-grain" arable land; in this process, the organic-inorganic mixed fertilizer, the special compound microbial agent are evenly mixed with the cultivated layer of soil.

[0037] A control experiment was conducted. The cultivated land in the control area was "non-grain" cultivated land that had not been treated in any way, and the cultivated land in the experimental area was "non-grain" cultivated land that had been treated with the above steps. Rice was planted at the same time. After 30 days, soil samples were taken from the cultivated land in the control area and the experimental area for detection of organic matter, water-soluble organic carbon, available nitrogen, available phosphorus, microbial biomass carbon and microbial biomass nitrogen. Sampling and testing were performed 10 times at different locations in the area and the average was calculated. Organic matter refers to life-derived substances in the soil, such as carbon-containing compounds, lignin, protein, resin and wax, etc., which mainly come from the residues, excrement and secretions of animals, plants and microorganisms. The higher the organic matter content, the higher the soil fertility. Water-soluble organic carbon refers to organic matter that can be extracted by water and can pass through a 0.45μm filter membrane. It is of great significance for conserving soil nutrients, maintaining soil fertility, effectively transforming nutrients, microbial activity and other soil processes. Fast-acting nitrogen refers to nitrogen in the soil that can be quickly absorbed by plants, mainly in the form of ammonium nitrogen and nitrate nitrogen. Fast-acting phosphorus refers to phosphorus in the soil that is more easily absorbed and utilized by plants, including phosphate ions in the soil solution, easily soluble inorganic phosphorus compounds and adsorbed phosphorus. Microbial biomass carbon and microbial biomass nitrogen refer to the carbon and nitrogen contents in microorganisms in the soil, respectively. Microbial biomass carbon and microbial biomass nitrogen directly participate in the soil biochemical transformation process, and are reserves of effective nutrients for plants in the soil. They can promote the effectiveness of soil nutrients and are important indicators of soil microbial activity and biomass.

[0038] The determination of organic matter in soil samples was carried out according to the method of Part VI of NY / T 1121.6-2006; the determination method of water-soluble organic carbon in soil samples was as follows: 10g of air-dried soil sample passed through a 2mm sieve was weighed, distilled water was added at a water-soil ratio of 2:1, constant temperature oscillation was performed at 25°C for 30min, and then the filtrate was filtered with a 0.45μm filter membrane, and the filtrate was directly determined by a TOC-1020A organic carbon analyzer; the test method of available nitrogen in soil samples was as follows: the soil sample was hydrolyzed with 1.0N sodium hydroxide to convert soil nitrogen into ammonia gas, which continuously escaped and was absorbed by boric acid, titrated with standard acid, and then the nitrogen content was calculated; the available phosphorus in soil samples was determined according to the method in HJ 704-2014; the microbial biomass carbon was determined according to the method in T / NAIA 008-2020; and the microbial biomass nitrogen was determined according to the method in T / NAIA 009-2020. The results are shown in Table 1.

[0039] .

[0040] The results showed that after using the method of the present invention to increase the carbon content and expand the soil nutrient pool of "non-grain" cultivated land, the nutrients in the soil of the experimental group increased significantly compared with the control group; in addition, the microbial biomass carbon and microbial biomass nitrogen increased significantly, indicating that the active microbial biomass in the soil increased significantly, which can continuously provide a large amount of carbon and nitrogen sources for the growth of food crops, proving that the method of this embodiment can achieve the carbon increase and expansion of the soil nutrient pool of "non-grain" cultivated land.

[0041] Further experiments found that organic-inorganic mixed fertilizers and special compound microbial agents are preferably mixed in a ratio of 1:0.001~1:0.5. It is preferred to apply 50-80 kg of organic-inorganic mixed fertilizers and 15 kg of special compound microbial agents per mu of arable land, which can achieve similar effects. The soil organic matter is greater than 12g / kg, the water-soluble organic carbon is greater than 80mg / kg, the available nitrogen is greater than 50mg / kg, the available phosphorus is greater than 25mg / kg, the microbial biomass carbon is greater than 80mg / kg and the microbial biomass nitrogen is greater than 25mg / kg. The operation can be carried out according to the specific situation of the "non-grain" arable land. Example 2: Composition experiment of organic-inorganic mixed fertilizer

[0042] In the early stage of the present invention, various ratios of organic-inorganic mixed fertilizers were tested. The following are several organic-inorganic mixed fertilizers that achieved good results in the test: Organic-inorganic mixed fertilizer 1: 70 parts of fully decomposed cow dung, 10 parts of inorganic nitrogen fertilizer, 10 parts of inorganic phosphorus fertilizer and 10 parts of inorganic potassium fertilizer; Organic-inorganic mixed fertilizer 2: 50 parts of fully decomposed cow dung, 20 parts of woody peat, 10 parts of inorganic nitrogen fertilizer, 10 parts of inorganic phosphorus fertilizer and 10 parts of inorganic potassium fertilizer; Organic-inorganic mixed fertilizer 3: 60 parts of fully decomposed cow dung, 20 parts of potassium humate, 10 parts of inorganic nitrogen fertilizer and 10 parts of inorganic phosphorus fertilizer; Organic-inorganic mixed fertilizer 4 (Example 1): 50 parts of fully decomposed cow dung, 20 parts of woody peat, 10 parts of inorganic nitrogen fertilizer, 20 parts of potassium humate and 10 parts of inorganic phosphate fertilizer; The experiments were all carried out in the manner of Example 1, sampling and testing the contents of organic matter, water-soluble organic carbon, available nitrogen and available phosphorus in the soil under the application of each group of organic-inorganic mixed fertilizers. Sampling was performed 10 times in the corresponding area, and the results were tested and averaged. The results are shown in Table 2.

[0043] .

[0044] The results show that the components of organic-inorganic mixed fertilizers have a very obvious effect on the soil nutrient pool of "non-grain" cultivated land. The effect of organic-inorganic mixed fertilizer 4, i.e. the organic-inorganic mixed fertilizer in Example 1, far exceeds that of other organic-inorganic mixed fertilizers, especially the effects on the two indicators of microbial biomass carbon and microbial biomass nitrogen are particularly obvious.

[0045] To further explore the reasons, the above four organic-inorganic mixed fertilizers were directly applied without mixing with the special composite microbial agent, and rice was planted. After 30 days, soil samples were taken for testing and it was found that there was little difference in the physical and chemical indicators of the soil; the reason is that the effective ingredients in the organic-inorganic mixed fertilizers need to be decomposed by microorganisms into nutrients directly used by plants, while the number of microorganisms in the "non-grain" cultivated land is small, and the populations contained therein have no obvious advantage in the decomposition of the above-mentioned organic-inorganic mixed fertilizers; and if the special composite microbial agent of Example 1 is added, compared with organic-inorganic mixed fertilizers 2 and organic-inorganic mixed fertilizers 3, organic-inorganic mixed fertilizers 4 can produce a significant improvement effect, indicating that woody peat and potassium humate have a synergistic effect on the germination and infection of AM fungi, which is beneficial to the growth of mycorrhizae.

[0046] Based on the above research, this embodiment prepared a variety of organic-inorganic mixed fertilizers, and the test results all showed that they could achieve good results. The optimal ratio of each component was: 40-60 parts of livestock and poultry manure, 15-25 parts of woody peat, 10-15 parts of inorganic nitrogen fertilizer, 15-25 parts of potassium humate and 5-10 parts of inorganic phosphorus fertilizer, calculated by weight; according to the above ratios, the soil organic matter was greater than 12g / kg, the water-soluble organic carbon was greater than 80mg / kg, the available nitrogen was greater than 50mg / kg, the available phosphorus was greater than 25mg / kg, the microbial biomass carbon was greater than 80mg / kg and the microbial biomass nitrogen was greater than 25mg / kg. Example 3: Composition experiment of special composite bacterial agent

[0047] The growth of food crops requires phosphorus, and the higher the phosphorus content in the soil, the less conducive it is to the germination and infection of AM fungi, which also limits the practical application of AM fungi. Therefore, the present invention attempts to find a way to promote the germination and infection of AM fungi in "non-food" cultivated soil with a high phosphorus content, and promote the growth of mycorrhizae.

[0048] The following methods are tested by the present invention and have good effects: Method 1: Bacillus megaterium is added as phosphate-solubilizing bacteria, and the special composite bacterial agent is composed of 8 parts of AM fungi screened in Example 1 and 2 parts of commercially available Bacillus megaterium; Method 2: Only the AM fungi screened in Example 1 are used, and the dosage (weight) is increased to three times that of the special composite bacterial agent in Example 1; Method 3 (Example 1): Adding Bacillus spp., the special composite bacterial agent is composed of 8 parts of AM fungi screened in Example 1 and 2 parts of commercially available Bacillus spp.; The rest of the experiments were conducted according to the method of Example 1, focusing on microbial biomass carbon and microbial biomass nitrogen to reflect the actual AM fungal germination and infection in the soil. The results are shown in Table 3.

[0049] .

[0050] The results showed that after using phosphate-solubilizing bacteria and increasing the dosage of AM fungi, the results of microbial biomass carbon and microbial biomass nitrogen were similar. The effect of adding Bacillus subtilis was significantly better than the above two methods, increasing the microbial biomass by about 2 times. It can be seen that Bacillus subtilis has a certain promoting effect on AM fungi in soils with high phosphorus content. The principle may be that higher phosphorus content can promote the expression of Bacillus subtilis and release certain substances into the soil, which can be used by AM fungi and promote the germination and infection of AM fungi. The specific mechanism of action needs further demonstration.

[0051] Based on the above research, this embodiment adjusts the ratio of AM fungi and Bacillus subtilis in the special composite bacterial agent, and finds that as long as Bacillus subtilis is present, a certain effect can be achieved; wherein, the preferred ratio is: the special composite bacterial agent includes 2-8 parts of AM fungi and 1-3 parts of Bacillus subtilis; according to the above ratio, the microbial biomass carbon is greater than 80 mg / kg and the microbial biomass nitrogen is greater than 25 mg / kg. Example 4: Experiment on the strains of arbuscular mycorrhizal fungi

[0052] The present invention obtains AM fungi by selecting "non-grain" cultivated land of economic forestry and fruit, collecting root systems of main crops and soil samples around their roots, mixing the collected soil samples with sterilized river sand (1:1), planting wheat, white clover and alfalfa in a greenhouse to induce the culture of AM fungi, and separating and extracting spores by wet sieving and decantation after the soil samples are sieved through a 20-mesh sieve, and after separation, multiple groups of AM fungal spores of different species are obtained.

[0053] AM fungi were further identified and isolated, and multiple fungal populations were obtained. According to the descriptions in the Manual for the identification of VA mycorrhizal fungi, Phylogeny and taxonomy of Glomeromycota (http: / / schuessler.userweb.mwn.de / amphylo) and INVAM (http: / / invam.wvu.edu / ), AM fungal species were identified, and the following species were obtained: Rhizophgus clarus , referred to as RC), sedum glabrata ( Acaulospora laevis , referred to as AL), Glomus juveniles ( Claroideoglomus etunicatum , referred to as CE), Glomus monosporus ( Glomus monosporum , referred to as GM), Glomus intraradices ( Glomus intraradices , referred to as GI) and Glomus terrestris ( Glomus versiforme , referred to as GV).

[0054] In this example, single strains and combinations of the above strains were used for experiments. A single strain or multiple strains were mixed in equal mass as AM fungi and prepared into a special composite bacterial agent with Bacillus subtilis in a weight ratio of 8:2. The other experimental steps were carried out according to the method in Example 1. It was found that most of the single strains or combinations had poor effects. In this example, single strains or combinations with better effects were selected, and the results of soil microbial biomass carbon and microbial biomass nitrogen in "non-grain" cultivated land after their application are shown in Table 4.

[0055] .

[0056] The results showed that GV had the best effect among the individual strains, but the effect of GV combined with other strains decreased, which might be the result of competition and antagonism between strains. Although the effects of RC and CE applied alone were poor, the combination of RC and CE significantly increased the microbial biomass carbon and microbial biomass nitrogen in the soil, which had a significant synergistic effect. If GV with better effect was added to the combination of RC and CE, the synergistic effect would be destroyed, which might be the result of competition between strains. The effects of other individual strains and strain combinations were worse than those in Table 4.

[0057] Compared with the results of Example 1, after RC and CE were combined into AM fungi, the other methods were the same, the microbial biomass carbon in the soil increased from 89.11 mg / kg to 124.58 mg / kg, and the microbial biomass nitrogen in the soil increased from 25.40 mg / kg to 41.69 mg / kg. The reason is that the present invention discovered and separated the core AM fungal species, discovered the synergy and competition between fungal populations, and targetedly improved the function of AM fungi by combining the two species of RC and CE, thereby further achieving carbon increase and expansion of the soil nutrient pool of "non-grain" cultivated land.

[0058] Further experiments found that the weight ratio of RC to CE between 1:0.1-1:10 can have a good effect, even if the soil microbial biomass carbon content is higher than 120 mg / kg and the microbial biomass nitrogen content is higher than 40 mg / kg; among them, the preferred weight ratio of RC to CE is 1:1. Example 5: Long-term carbon enrichment and capacity expansion experiment of specific AM fungal species

[0059] According to Example 4, Sporangium minguigensis ( Rhizophgus clarus ) and Glomus natans ( Claroideoglomus etunicatum) combination as the preferred strain of AM fungi, but field experiments have found that although it can quickly increase the nutrient content of "non-grain" cultivated land, it is only applied once before planting grain crops, and only organic fertilizer or inorganic fertilizer can be added to the topsoil later. The time to maintain soil nutrients is also an issue worth considering. AM fungi without separated strains can maintain soil nutrients at a high content for more than 8 months, which is enough to cover the entire cycle of various grain crops, while the RC and CE combination can only maintain soil nutrients at a high content for about 6 months, which can meet the cycle of major grain crops such as rice, corn and soybeans, but for winter wheat that requires about 8 months, it cannot cover its heading and maturity periods; therefore, in order to further expand the scope of application of the present invention, this embodiment attempts to find a strain combination based on RC and CE, which can further prolong the time of maintaining high soil nutrient content.

[0060] One of the ideas is to increase the number of microorganisms into the special composite microbial agent, but the interaction between plants, microorganisms and microorganisms is extremely complex. The present invention has conducted a large number of experiments. On the basis of the preferred AM fungus composition in Example 4 and the special composite microbial agent composition in Example 1, another microorganism accounting for 2 parts by weight is additionally added. After treating the "non-grain" arable land in the manner of Example 1, winter wheat is planted. In the 4th, 6th and 8th months, the soil in the corresponding area is sampled and various soil physical and chemical indicators are tested. The samples are tested 10 times and the average is calculated. The trends of the indicators are the same, so the water-soluble organic carbon content is used as a reference indicator. Some experimental results are shown in Table 5.

[0061] .

[0062] It can be seen that only by adding Trichoderma harzianum can the long-term carbon increase and expansion of the soil nutrient pool of "non-grain" cultivated land be achieved, and the water-soluble organic carbon content is maintained above 140 mg / kg for 4-8 months. Its working principle may be to improve certain biochemical processes of wheat, enhance the interaction between wheat and AM fungi, and promote soil nutrient regeneration; further studies have found that adding 1-3 parts of Trichoderma harzianum to special compound bacterial agents can have a good effect, maintaining the soil water-soluble organic carbon content above 140 mg / kg for 4-8 months.

[0063] Another idea is to add substances that promote the interaction between plants and microorganisms as adjuvants, but there is currently a lack of research on how to promote the interaction between plants and microorganisms. The present inventors have conducted a large number of experiments, adding some substances that wheat may be able to directly or indirectly utilize as adjuvants, and conducted experiments in the same manner as above. The results are shown in Table 6.

[0064] .

[0065] The results showed that the addition of plant hormones such as indoleacetic acid and gibberellins had no obvious effect on the long-term carbon expansion of "non-grain" cultivated land, but the addition of polyaspartic acid and polyarginine had a certain effect, which could maintain the soil water-soluble organic carbon content above 120 mg / kg for 4-8 months. The principle of action may be to improve certain biochemical processes of wheat, enhance the interaction between wheat and AM fungi, and promote soil nutrient regeneration; further studies found that adding 0.4-1.2 parts of seaweed oligosaccharides, 0.2-0.5 parts of polyaspartic acid and 0.7-1.5 parts of polyarginine to special compound bacterial agents could maintain the soil water-soluble organic carbon content above 120 mg / kg for 4-8 months.

[0066] In summary, based on the combination of RC and CE strains, the addition of Trichoderma harzianum or seaweed oligosaccharides, polyaspartic acid and polyarginine as adjuvants can be selected to prolong the maintenance time of the method of the present invention on carbon increase and expansion of the soil nutrient pool of "non-grain" cultivated land. Example 6: Comparison of soil properties under different treatments of “non-grain” cultivated land

[0067] On October 19, 2023, experts from Zhejiang Academy of Agricultural Sciences and Zhejiang A&F University conducted field yield testing and acceptance of rice planted in the demonstration base. The experimental demonstration area is located in Shangli Village, Xiangxi Town, Lanxi City, covering an area of ​​2,600 mu. The rice variety tested is "Huazhongyou 9326". Four treatments were set up in the experimental area: a blank control group (CK), a group applying chemical fertilizers (EG1), a group applying chemical fertilizers and organic fertilizers (EG2), and a group applying organic-inorganic mixed fertilizers and special compound microbial agents (EG3); among them, the blank control group (CK) was directly planted with rice on the "non-grain" cultivated land without any treatment; the group applying chemical fertilizers (EG1) was applied with inorganic nitrogen, phosphorus and potassium fertilizers on the "non-grain" cultivated land in the early stage, and 60 kg of compound fertilizers (nitrogen: phosphorus: potassium = 15:15:15) were applied per mu; the group applying chemical fertilizers and organic fertilizers (EG2) was applied with 60 kg of compound fertilizers (nitrogen: phosphorus: potassium = 15:15:15) and 30 kg of fully decomposed cow dung per mu on the "non-grain" cultivated land in the early stage, and the fully decomposed cow dung contained 16-20% organic matter; the specific method of applying organic-inorganic mixed fertilizers and special compound microbial agents (EG3) was as follows: First, the "non-grain" arable land was plowed, and the plowing method was as follows: about 20-30 cm of soil was turned downward, and the process was repeated 4 times; organic-inorganic mixed fertilizer was prepared: 50 parts of high-temperature sterilized livestock and poultry manure, 20 parts of commercially available woody peat, 20 parts of commercially available inorganic nitrogen fertilizer, 20 parts of commercially available potassium humate and 10 parts of commercially available inorganic phosphate fertilizer were taken according to weight, and mixed evenly; the technical indicators of each component in the organic-inorganic mixed fertilizer were the same as those in Example 1; special composite microbial agent was prepared: economic forestry and fruit "non-grain" arable land was selected, and the root system and root soil samples of the main crops were collected, and the collected soil samples were mixed with sterilized river sand (1:1), and wheat, white clover and alfalfa were planted in a greenhouse to induce AM fungi, and the soil samples were passed through a 20-mesh sieve and spores were separated and extracted by wet sieving and decantation to obtain AM fungi; according to the method in Example 4, the spores were identified, separated and mixed with 1:1 Ming root cysts ( Rhizophgus clarus ) and Glomus natans ( Claroideoglomus etunicatum ) combination as the preferred strain of AM fungi; calculated by weight, 8 parts of cultured AM fungi and 2 parts of commercially available Bacillus subtilis were mixed evenly, and the number of viable bacteria (cfu) was greater than 100 million / g; 60 kg of the above-mentioned organic-inorganic mixed fertilizer and 15 kg of the above-mentioned special composite bacterial agent were applied per mu of cultivated land; the application method was: evenly mix the organic-inorganic mixed fertilizer and the special composite bacterial agent, evenly spread them on the topsoil, plow down 20-30 cm, and repeat the rotary tillage 4 times.

[0068] 1. Comparison of soil organic matter Soil organic matter is an important component of the solid phase of soil and one of the main sources of plant nutrition. It can promote plant growth and development, improve the physical properties of soil, promote the activities of microorganisms and soil organisms, promote the decomposition of nutrients in soil, and improve the soil's fertility retention and buffering properties. It is closely related to the soil's structure, aeration, permeability, adsorption, and buffering properties. Usually, under the same or similar conditions, within a certain content range, the content of organic matter is positively correlated with the soil fertility level. The test method for organic matter is the same as in Example 1. Figure 1 As shown, compared with the blank control group (CK), the group applying chemical fertilizers (EG1), and the group applying chemical fertilizers and organic fertilizers (EG2), the group applying organic-inorganic mixed fertilizers and special composite microbial agents (EG3) in the "non-grain" cultivated land significantly increased the organic matter content of the soil during the rice growing season, and the organic matter content reached 3.92%.

[0069] 2. Soil cation exchange capacity Soil cation exchange capacity affects soil buffering capacity and is also an important basis for evaluating soil fertility retention, soil improvement and rational fertilization. The soil is extracted with hexaamminecobalt trichloride solution and then measured by spectrophotometry. Figure 2As shown, compared with the blank control group (CK), the group applying chemical fertilizers (EG1) increased the soil cation exchange capacity by about 7.5%; compared with the blank control group (CK), the group applying chemical fertilizers and organic fertilizers (EG2) increased the soil cation exchange capacity by about 14%; compared with the blank control group (CK), the group applying organic-inorganic mixed fertilizers and special compound bacterial agents (EG3) in "non-grain" cultivated land significantly increased the soil cation exchange capacity of the soil during the rice growing season, by about 37%.

[0070] 3. Soil nutrient content The method for determining soil nutrient content is the same as in Example 1 and the national standard NY / T 889-2004 for potassium determination, such as Figure 3 As shown, compared with the blank control group (CK), the group applying chemical fertilizers (EG1) increased the soil carbon content by about 10%; compared with the blank control group (CK), the group applying chemical fertilizers and organic fertilizers (EG2) increased the soil carbon content by about 60%; compared with the blank control group (CK), the group applying organic-inorganic mixed fertilizers and special compound microbial agents (EG3) in "non-grain" cultivated land significantly increased the soil carbon content during the rice growing season, increasing it to 4.5 times that of the control group.

[0071] Compared with the blank control group (CK), the group applying chemical fertilizer (EG1), the group applying chemical fertilizer and organic fertilizer (EG2), and the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3) significantly increased the total nitrogen content in the soil during the rice growing season. Among them, the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3) had the highest total nitrogen content in the soil. In addition, the total phosphorus content and total potassium content in the soil of the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3) were significantly higher than those of the other groups.

[0072] 4. Soil bulk density Soil bulk density can be used to calculate the weight of a certain area of ​​arable soil and soil porosity; it can also be used as one of the indicators of soil maturity. The soil with a higher degree of maturity usually has a lower bulk density. It is measured according to the method of Part 4 of NY / T 1121.4-2006 Soil Testing; Figure 4 As shown, compared with the blank control group (CK), the soil bulk density of the group applying chemical fertilizer (EG1), the group applying chemical fertilizer and organic fertilizer (EG2), and the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3) was reduced during the rice growing season. Among them, the soil bulk density of the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3) in the "non-grain" cultivated land was the lowest.

[0073] 5. Soil aggregates Soil aggregates refer to the sum of aggregates of different sizes, properties, porosities, mechanical stability and water stability contained in the soil. Soil structure is an important physical property of soil. It refers to the comprehensive characteristics of the number, size, properties, properties, mutual arrangement and corresponding porosity of single and complex particles of soil. The soil aggregate structure is one of the indicators for identifying soil fertility. Soil aggregates are divided into the following categories according to their size: <0.053mm, 0.53-0.25mm, 0.25-2mm and >2mm. The detection is carried out according to the method of Part 19 of Soil Testing of NYT 1121.19-2008; the proportion of soil aggregates in the four groups is as follows: Figure 5 As shown. Compared with the blank control group (CK), the group applying chemical fertilizer (EG1) increased the proportion of soil aggregates <0.053 mm; compared with the blank control group (CK), the group applying chemical fertilizer and organic fertilizer (EG2) reduced the proportion of soil aggregates <0.053 mm; compared with the blank control group (CK), the group applying organic-inorganic mixed fertilizer and special composite microbial agent (EG3) increased the proportion of soil aggregates 0.25-2 mm, which proved that it promoted the formation of soil aggregates and was beneficial to the fixation of nutrients in "non-grain" cultivated soil.

[0074] 6. Soil infrared spectrum characteristics Soil infrared spectrum (wave number 4000~400cm -1 ) can be reflected by the fundamental frequency vibration absorption and dipole moment changes generated by the stretching vibration and rotational motion of atoms, and displayed in the form of absorption peaks in the spectrum. The structure and content of chemical components can be judged by the absorption peak position, morphology and intensity of characteristic absorption peaks, which can indicate the composition and diversity of soil carbon. The wave number range of the group frequency region, functional group region or characteristic region is 4000~1300 cm -1 , which is often used to identify functional groups. -1 The infrared absorption peak near 2930cm can be used to indicate the aromatic carbon components or amide bonds in the soil. Aromatic carbon is a carbon component that is difficult for plants to decompose. Amide bonds come from proteins. Proteins from soil microorganisms are also relatively stable. Therefore, the absorption peak here can usually indicate relatively stable soil organic components. -1 The infrared absorption peak near is soil aliphatic carbon, which can be used to indicate soil organic components that are relatively easy to decompose. Figure 6As shown in the figure, compared with the blank control group (CK), the group applying chemical fertilizer (EG1), the group applying chemical fertilizer and organic fertilizer (EG2), and the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3) all significantly increased the organic carbon content, among which the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3) had a greater increase in soil organic carbon content, indicating that the stable carbon content in the soil increased; although the aliphatic carbon, that is, the carbon that is easier to decompose, in the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3) was significantly lower than that in the group applying chemical fertilizer and organic fertilizer (EG2), its clay hydroxyl group was significantly higher than that in the group applying chemical fertilizer and organic fertilizer (EG2), indicating that it has better fertilizer retention ability.

[0075] 7. Diversity, structure and function of soil microbial communities High-throughput sequencing was used to analyze the changes in soil microbial community diversity, composition, and function in "non-grain" cultivated land under different fertilization treatments. Microbial diversity is studied in community ecology. The abundance and diversity of microbial communities can be reflected through the diversity analysis of a single sample (Alpha diversity). The Chao index is used to calculate community richness, and the Shannon index is used to calculate community diversity. Figure 7 In the figure, red, green, blue and purple represent the blank control group (CK), the group with chemical fertilizer (EG1), the group with chemical fertilizer and organic fertilizer (EG2) and the group with organic-inorganic mixed fertilizer and special compound microbial agent (EG3), respectively. Figure 7 It can be seen that there is a significant difference between the group applying chemical fertilizer and organic fertilizer (EG2) and the group applying organic-inorganic mixed fertilizer and special compound microbial agent (EG3). In summary, the addition of organic-inorganic mixed fertilizer increases the richness and diversity of soil bacteria, while the application of special compound microbial agent reduces the richness and diversity of the community.

[0076] The ADONIS analysis between the groups showed that there were extremely significant differences in the bacterial communities between the "non-grain" cultivated land soils under different treatments (R 2 =0.548, P=0.001). Figure 8 In the figure, red, green, blue and purple represent the blank control group (CK), the group with chemical fertilizer (EG1), the group with chemical fertilizer and organic fertilizer (EG2) and the group with organic-inorganic mixed fertilizer and special compound microbial agent (EG3), respectively; Figure 8The PCoA analysis and UPGMA cluster analysis results showed the differences in the structure of soil bacterial communities under different treatments. It can be seen that the blank control group (CK) samples were clustered into one category, the chemical fertilizer application group (EG1) and the chemical fertilizer and organic fertilizer application group (EG2) samples were clustered into one category, and the organic-inorganic mixed fertilizer and special composite bacterial agent application group (EG3) samples were clustered into one category. Therefore, for the soil bacterial community structure, on the basis of the application of chemical fertilizers, the effect of the single application of organic fertilizer on the composition of soil bacterial communities was slightly smaller, while the application of organic-inorganic mixed fertilizers and special composite bacterial agents could effectively reshape the soil bacterial community structure.

[0077] Fig. 9 The composition differences of soil bacterial communities at the phylum level in "non-grain" cultivated land under different treatments were analyzed. Compared with other treatments, the soils treated with organic-inorganic mixed fertilizer and special compound bacterial agent group (EG3) had a higher concentration of Firmicutes ( Firmicutes ), Actinobacteria ( Actinobacteriota ), Bacteroidetes ( Bacteroidota )and Myxococcota In addition, chemical fertilizer and organic fertilizer + chemical fertilizer treatments significantly increased the relative abundance of bacteria in the soil. Nitrospirota However, the application of organic-inorganic mixed fertilizer and special compound bacterial agent group (EG3) Nitrospirota The abundance of bacteria decreased.

[0078] Fig.10 Based on the FAPROTAX analysis of soil bacterial communities, the functional changes of soil bacterial communities in "non-grain" cultivated land under different treatments were predicted. It can be seen that the application of chemical fertilizers significantly inhibited the organic matter decomposition metabolism, xenobiotic degradation, methane metabolism, nitrogen cycle, manganese cycle and other functions of soil microbial communities. On the basis of the application of chemical fertilizers, the single application of organic fertilizers can only slightly promote the recovery of soil bacterial community functions, while the application of organic-inorganic mixed fertilizers and special composite bacterial agents (EG3) effectively improves the organic matter decomposition metabolism and nitrogen cycle functions of soil microbial communities; the above methods for detecting the diversity, structure and function of soil microbial communities are all existing public methods.

[0079] In summary, the application of organic-inorganic mixed fertilizer and special composite microbial agent according to the method of the present invention can significantly increase soil organic matter, available potassium, cation exchange capacity, reduce soil bulk density, and the effect of improving soil properties after applying organic-inorganic mixed fertilizer and special composite microbial agent group is more significant compared with chemical fertilizer and chemical fertilizer + organic fertilizer treatment. At the same time, the content of aromatic carbon that is difficult to decompose in the soil increases more, while the aliphatic carbon that is easier to decompose decreases more, indicating that the application of organic-inorganic mixed fertilizer and special composite microbial agent group increases the stable carbon content of the soil and gives the soil better fertilizer retention ability. In addition, the effect of single chemical fertilizer treatment on the effective phosphorus content of the soil is not significant, but it can promote the formation of soil microaggregate structure (<0.25 mm) and reduce soil pH; while chemical fertilizer + organic fertilizer treatment can significantly promote the formation of soil macroaggregate structure (>0.25 mm) and increase the effective phosphorus content, and the application of organic-inorganic mixed fertilizer and special composite microbial agent group, the effective phosphorus content increases more significantly and the macroaggregate (>0.25mm) structure accounts for 56%. In addition to physical and chemical properties, the application of organic-inorganic mixed fertilizers and special compound microbial agents also significantly changed the structure, composition and function of soil bacterial communities. Among them, chemical fertilizer treatment inhibited the organic matter decomposition metabolism, xenobiotic degradation, methane metabolism, nitrogen cycle, manganese cycle and other functions of soil microbial communities. On the basis of the application of chemical fertilizers, the single application of organic fertilizers failed to effectively change the composition of soil bacterial communities and could only slightly promote functional recovery. The application of organic-inorganic mixed fertilizers and special compound microbial agents effectively reshaped the structure of soil bacterial communities, making the Bacteroidetes ( Bacteroidota )、 Myxococcota Phylum, Firmicutes Firmicutes ) The relative abundance of bacteria increased significantly, promoting the decomposition metabolism of organic matter and the improvement of nitrogen cycle function of the microbial community. Example 7: Comparison of grain crop yields in different treatments of “non-grain” farmland

[0080] On October 19, 2023, experts from Zhejiang Academy of Agricultural Sciences and Zhejiang A&F University conducted field yield measurement and acceptance of rice planted in the demonstration base. The experimental demonstration area is located in Shangli Village, Xiangxi Town, Lanxi City, covering an area of ​​2,600 mu. The rice variety tested is "Huazhongyou 9326". Four treatments were set up in the experimental area: a blank control group (CK), a group applying chemical fertilizers (EG1), a group applying chemical fertilizers and organic fertilizers (EG2), and a group applying organic-inorganic mixed fertilizers and special composite microbial agents (EG3). The four groups were treated the same as in Example 6.

[0081] The expert group used harvesters to harvest and measure the yield of the above four experimental plots. After removing impurities from the rice, the net dry rice yield per mu was calculated based on the standard moisture content of 14.5%. The specific results are shown in Table 7.

[0082] .

[0083] It can be seen that the method for increasing carbon and expanding the soil capacity of "non-grain" cultivated land provided by the present invention can significantly increase the yield of grain crops planted on "non-grain" cultivated land.

[0084] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto, and any equivalent modifications or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention.

Claims

1. A method for increasing carbon and expanding the nutrient pool of soil in "non-grain" cultivated land in the south, characterized in that: Includes steps: S1, tillage, turn out 20-30 cm of soil downwards, repeat 2-6 times; S2, applying organic-inorganic mixed fertilizer and special composite bacterial agent on the topsoil, and ploughing again according to step S1; The organic-inorganic mixed fertilizer includes fully decomposed cow dung, woody peat, inorganic nitrogen fertilizer, potassium humate and inorganic phosphorus fertilizer; the fully decomposed cow dung contains 16-20% organic matter; the woody peat contains 55-75% humic acid; the organic acid salt content of potassium humate is ≥80%; the nitrogen content of the inorganic nitrogen fertilizer is ≥15%; the phosphorus content of the inorganic phosphorus fertilizer is ≥8%; The special composite bacterial agent comprises arbuscular mycorrhizal fungi and colloid bacillus; the arbuscular mycorrhizal fungi is composed of spore mold (Rhizophgus clarus ) and Glomus juveniles ( Claroideoglomus etunicatum )composition.

2. The method according to claim 1, characterized in that In the step S2, the ratio of the organic-inorganic mixed fertilizer to the special composite bacterial agent is 1:0.001 to 1:0.5 by weight.

3. The method according to claim 1 or 2, characterized in that In the step S2, 50-80 kg of organic-inorganic mixed fertilizer is applied per mu of cultivated land.

4. The method according to claim 1, characterized in that Calculated by weight, the organic-inorganic mixed fertilizer includes 40-60 parts of fully decomposed cow dung, 15-25 parts of woody peat, 10-15 parts of inorganic nitrogen fertilizer, 15-25 parts of potassium humate and 5-10 parts of inorganic phosphorus fertilizer.

5. The method according to claim 1, characterized in that Calculated by weight, the ratio of the spore forming mold to the young spore forming mold is 1:0.1-1:

10.

6. The method according to claim 1 or 5, characterized in that Calculated by weight, the special composite bacterial agent includes 2-8 parts of arbuscular mycorrhizal fungi and 1-3 parts of mucilaginous Bacillus.

7. The method according to claim 1, characterized in that The special composite bacterial agent also includes Trichoderma harzianum.

8. The method according to claim 1, characterized in that The special composite bacterial agent also includes auxiliary agents, which include seaweed oligosaccharides, polyaspartic acid and polyarginine.

9. The method according to claim 8, characterized in that Calculated by weight, the special composite bacterial agent includes 2-8 parts of arbuscular mycorrhizal fungi, 1-3 parts of colloid Bacillus, 0.4-1.2 parts of seaweed oligosaccharides, 0.2-0.5 parts of polyaspartic acid and 0.7-1.5 parts of polyarginine.

10. A composition for increasing carbon and expanding the nutrient pool of soil in "non-grain" cultivated land in the south, characterized in that: The invention comprises an organic-inorganic mixed fertilizer and a special composite microbial agent, wherein the organic-inorganic mixed fertilizer comprises fully decomposed cow dung, woody peat, inorganic nitrogen fertilizer, potassium humate and inorganic phosphorus fertilizer; the fully decomposed cow dung contains 16-20% organic matter; the woody peat contains 55-75% humic acid; the organic acid salt content of the potassium humate is ≥80%; the nitrogen content of the inorganic nitrogen fertilizer is ≥15%; the phosphorus content of the inorganic phosphorus fertilizer is ≥8%; the special composite microbial agent comprises arbuscular mycorrhizal fungi and mucilaginous bacillus; the arbuscular mycorrhizal fungi is composed of Sporangiophora acuminata ( Rhizophgus clarus ) and Glomus juveniles ( Claroideoglomus etunicatum )composition.

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