A complex mycorrhizal fungus fertilizer suitable for the construction of protective forests in desert oasis regions and its preparation method and application

Abstract

The application provides a compound mycorrhizal fungus fertilizer suitable for planting of a shelter forest in a desert oasis area and a preparation method and application thereof, and belongs to the technical field of tree planting. The compound mycorrhizal fungus fertilizer suitable for planting of a shelter forest in a desert oasis area comprises a compound arbuscular mycorrhizal fungus agent, a compound ectomycorrhizal fungus agent, fermented fungus dregs, peat, vermiculite, humic acid powder, biochar, corn cob powder and trehalose. The compound mycorrhizal fungus fertilizer can solve the problems of single tree species, single mycorrhizal type, insufficient drought resistance and growth promotion effect, insufficient transportation, storage and rhizosphere colonization stability of the existing mycorrhizal fungus agent, and is especially suitable for planting, growth promotion, drought resistance and rhizosphere environment improvement of Xinjiang poplar, scots pine and their mixed shelter forest in the arid oasis area of Xinjiang Uygur Autonomous Region, China.

Description

Technical Field

[0001] This invention belongs to the field of forestry establishment technology, specifically relating to a compound mycorrhizal fertilizer suitable for shelterbelt establishment in desert oasis areas, its preparation method, and its application. Background Technology

[0002] The desert oasis areas of Xinjiang Uygur Autonomous Region, China, especially the oases in southern Xinjiang and Aksu, are characterized by low rainfall, high evaporation, a prominent contradiction between water supply and demand, and unstable irrigation water supply. Some areas also suffer from insufficient soil fertility, poor rhizosphere environment, and salinization. Populus tomentosa and Pinus sylvestris are important tree species in the construction of oasis shelterbelts, farmland shelterbelts, and ecological barriers in Xinjiang. However, during the seedling planting and sapling establishment stages, water constraints, insufficient irrigation, and salinized soil environments easily lead to decreased root water absorption capacity, limited nutrient absorption, reduced photosynthetic efficiency, increased accumulation of reactive oxygen species, and insufficient biomass accumulation, thus affecting seedling survival, growth and development, and the quality of shelterbelt establishment.

[0003] Traditional fertilizers primarily improve soil nutrient supply by supplementing nitrogen, phosphorus, potassium, or organic matter. However, their effects are mainly concentrated on nutrient replenishment and soil fertility enhancement, with limited impact on improving the rhizosphere microecology, expanding root absorption range, establishing mycorrhizal symbiotic systems, and enhancing plant resilience under water-limited conditions in Xinjiang's arid oasis regions. Especially in Xinjiang's desert oasis areas, where water resources are severely constrained, evaporation is intense, irrigation water supply is unstable, and some soils are salinized, relying solely on traditional fertilizers is insufficient to effectively address issues such as slow seedling establishment, unstable rhizosphere environment, low water use efficiency, weak nutrient absorption capacity, and inadequate drought resistance.

[0004] Mycorrhizae are mutually beneficial symbiotic relationships formed between fungi and plant roots. Existing publicly available technologies suffer from limitations such as limited applicability to a single tree species, limited mycorrhizal types, insufficient synergistic colonization of different mycorrhizae, and inadequate stability in preservation and application in arid oasis areas. Therefore, there is a lack in this field of compound mycorrhizal fertilizers that can fully meet the needs of establishing shelterbelts of Populus tomentosa and Pinus sylvestris in arid oasis areas of Xinjiang. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a compound mycorrhizal fertilizer suitable for the establishment of shelterbelts in arid oasis areas of Xinjiang Uygur Autonomous Region, China, especially suitable for the establishment, growth promotion, drought resistance and rhizosphere environment improvement of Xinjiang poplar, Scots pine and their mixed shelterbelts in arid oasis areas of Xinjiang Uygur Autonomous Region, China.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a compound mycorrhizal fertilizer suitable for establishing protective forests in desert oasis areas, comprising the following raw materials by weight: 10-15 parts of compound arbuscular mycorrhizal agent, 5-15 parts of compound ectomycorrhizal agent, 20-30 parts of fermented mycelium residue, 15-21 parts of peat, 8-12 parts of vermiculite, 2-6 parts of humic acid powder, 2-6 parts of biochar, 10-16 parts of corn cob powder, and 0.5-1.5 parts of trehalose; the compound arbuscular mycorrhizal agent is composed of Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus claroideum agents, and the compound ectomycorrhizal agent is composed of ectomycorrhizal fungi of *Mallotus philippinensis* and *Mallotus lilacinus*.

[0007] Preferably, the weight ratio of the Funneliformis mosseae fungal agent, Rhizophagus irregularis fungal agent, and Claroideoglomus claroideum fungal agent is 1:(0.8~1.2):(0.8~1.2); the number of spores in the compound arbuscular mycorrhizal fungal agent is not less than 100 / g, the number of propagules is not less than 120 / g, and the host root mycorrhizal infection rate is not less than 50%.

[0008] Preferably, the ectomycorrhizal fungal agent is *Lepista irina* FM420, and the ectomycorrhizal fungal agent is *Lepista nuda* FM421; the weight ratio of *Lepistairina* FM420 to *Lepista nuda* FM421 is 1:0.8~1.2; the viable count in the compound ectomycorrhizal fungal agent is not less than 1.0 × 10⁻⁶. 8 CFU / g.

[0009] Preferably, in the compound mycorrhizal fertilizer, the number of viable ectomycorrhizae is not less than 1.0 × 10⁻⁶. 7 CFU / g; the compound mycorrhizal fertilizer contains at least 12 spores / g and at least 15 vegetative cells / g of arbuscular mycorrhizae; the moisture content of the compound mycorrhizal fertilizer is 20%~35%.

[0010] Preferably, the Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus claroideum inoculants are obtained by propagation from host plants; the host plants include white clover or red clover.

[0011] Preferably, the propagation method includes the following steps: mixing Funneliformis mosseae, Rhizophagus irregularis, or Claroideoglomus claroideum with a propagation substrate, sowing a host plant, cultivating and propagating, cutting off the aboveground parts of the host plant, and collecting the propagated material containing arbuscular mycorrhizal spores, mycelia, infected root segments, and rhizosphere substrate to obtain Funneliformis mosseae inoculant, Rhizophagus irregularis inoculant, or Claroideoglomus claroideum inoculant; the propagation substrate is composed of sand, vermiculite, and peat; the mass ratio of sand, vermiculite, and peat is 2:1:1; the mass ratio of Funneliformis mosseae, Rhizophagus irregularis, or Claroideoglomus claroideum to the propagation substrate is 5~10:100; the cultivation and propagation temperature is 20~28℃, and the cultivation and propagation time is 10~12 weeks.

[0012] Preferably, the preparation method of the ectomycorrhizal Lepista irina FM420 inoculant or the ectomycorrhizal Lepista nuda FM421 inoculant includes the following steps: activating the ectomycorrhizal Lepista irina FM420 or the ectomycorrhizal Lepista nuda FM421, inoculating them into MMN liquid medium, and shaking culture to obtain the ectomycorrhizal Lepista irina FM420 mycelial suspension or the ectomycorrhizal Lepista nuda FM421 mycelial suspension, which are the ectomycorrhizal Lepista irina FM420 inoculant or the ectomycorrhizal Lepista nuda FM421 inoculant; the shaking culture conditions are 23~27℃, 120~140 r / min, and culture for 7~15 days.

[0013] The present invention also provides a method for preparing the above-mentioned compound mycorrhizal fertilizer, comprising the following steps: mixing fermented mycelium residue, peat, vermiculite, humic acid powder, biochar, corn cob powder and trehalose to obtain a mixture; mixing the mixture with a compound ectomycorrhizal agent under light-protected conditions and a temperature below 30°C; and finally adding a compound arbuscular mycorrhizal agent and mixing under light-protected conditions and a temperature below 30°C to obtain the compound mycorrhizal fertilizer.

[0014] This invention also provides the application of the above-mentioned compound mycorrhizal fertilizer in the establishment of shelterbelts in desert oasis areas, wherein the shelterbelts include Xinjiang poplar shelterbelts, Scots pine shelterbelts, or mixed shelterbelts of Xinjiang poplar and Scots pine.

[0015] Preferably, the compound mycorrhizal fertilizer is applied by means of application to the root zone of the planting hole or by application in trenches around the root zone, with an application depth of 5-15 cm. The compound mycorrhizal fertilizer is in direct contact with the root system or at a distance of 2-5 cm from the main root. The application amount of the compound mycorrhizal fertilizer is 80-120 g / plant.

[0016] The beneficial effects of this invention are: The compound mycorrhizal fertilizer provided by this invention can solve the problems of existing mycorrhizal agents, such as limited applicable tree species, limited mycorrhizal types, insufficient drought resistance and growth promotion effects, and insufficient stability in transportation, preservation, and rhizosphere colonization. It is especially suitable for the establishment, growth promotion, drought resistance, and rhizosphere environment improvement of Populus tomentosa, Pinus sylvestris, and their mixed shelterbelts in the arid oasis areas of Xinjiang Uygur Autonomous Region, China.

[0017] The compound mycorrhizal fertilizer provided by this invention has the following advantages: First, it can simultaneously meet the mycorrhizalization needs of both arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) host plants; second, it can promote the growth of Populus tomentosa under drought stress and increase biomass accumulation; third, it can improve the survival rate of Pinus sylvestris under insufficient irrigation conditions and increase biomass; fourth, it can reduce oxidative damage to shelterbelts under drought or insufficient irrigation conditions; fifth, it can improve net photosynthetic rate and water use efficiency; sixth, it can improve nitrogen absorption and resource utilization capacity; seventh, it can optimize the rhizosphere environment in arid areas and enhance water retention, fungal retention, aeration, and drought resistance; and eighth, the compound mycorrhizal fertilizer of this invention has low production cost, which improves its applicability for promotion. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the application method of the compound mycorrhizal fertilizer (AM-ECM compound mycorrhizal fertilizer) of this invention to the rhizosphere of planting holes for poplar and pine in Xinjiang.

[0019] Figure 2 This is a flowchart illustrating the preparation process of the AM-ECM compound mycorrhizal fertilizer of this invention. Detailed Implementation

[0020] This invention provides a compound mycorrhizal fertilizer suitable for establishing protective forests in desert oasis areas, comprising the following raw materials by weight: 10-15 parts of compound arbuscular mycorrhizal agent, 5-15 parts of compound ectomycorrhizal agent, 20-30 parts of fermented mycelium residue, 15-21 parts of peat, 8-12 parts of vermiculite, 2-6 parts of humic acid powder, 2-6 parts of biochar, 10-16 parts of corn cob powder, and 0.5-1.5 parts of trehalose; the compound arbuscular mycorrhizal agent is composed of Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus claroideum agents, and the compound ectomycorrhizal agent is composed of ectomycorrhizal fungi of *Mallotus philippinensis* and *Mallotus lilacinus*.

[0021] In the compound mycorrhizal fertilizer of this invention, the compound ectomycorrhiza serves to provide active mycorrhizal hyphae, and the preferred amount of the compound ectomycorrhiza is 11-14 parts, more preferably 12.5 parts; the compound arbuscular mycorrhizal agent serves to provide arbuscular mycorrhizal spores, hyphae, and infected root segments, and the preferred amount of the compound arbuscular mycorrhizal agent is 11-14 parts, more preferably 12.5 parts; the fermented substrate has a high organic matter content and a loose structure, which is suitable for the attachment of ectomycorrhizal mycorrhizal hyphae and serves as a buffer carrier for arbuscular mycorrhizal spores and infected root segments, and the preferred amount of the fermented substrate is 22-28 parts, more preferably 24-26 parts; peat has water retention and bacterial preservation functions and serves as the main carrier, and the preferred amount of the peat is 16-20 parts, more preferably 17-19 parts. Vermiculite retains water and allows for air permeability, protecting spores and mycelia. The preferred amount of vermiculite is 9-11 parts, more preferably 10 parts. Humic acid powder improves saline-alkali soil and the rhizosphere environment, promoting root growth. The preferred amount of humic acid powder is 3-5 parts, more preferably 4 parts. Biochar increases pore structure and enhances the adhesion of the fungal agent. The preferred amount of biochar is 3-5 parts, more preferably 4 parts. Corn cob powder increases carrier porosity, improves aeration, and provides a loose substrate for fungal attachment. The preferred amount of corn cob powder is 11-15 parts, more preferably 12-14 parts. Trehalose protects mycelia and spores and improves resistance to drying. The preferred amount of trehalose is 0.7-1.2 parts, more preferably 1 part. This compound mycorrhizal fertilizer is an active microbial fertilizer and should not be applied simultaneously with fungicides. If fungicides must be used, it is recommended to wait at least 2 weeks. Avoid high-temperature exposure, prolonged exposure to sunlight, concentrated application of high-salt fertilizers, and waterlogging around the roots before and after application. In this invention, arbuscular mycorrhizal fungi primarily promote phosphorus absorption and fine root development, improving the early establishment ability of seedlings; ectomycorrhizal fungi primarily enhance the ability to construct the rhizosphere ectomycorrhizal mycelial network, improving water acquisition and stress resistance; the two types of mycorrhizae are complementary in ecological niche and function. Arbuscular mycorrhizal fungi promote the rapid establishment of the absorbing root system in seedlings, while ectomycorrhizae enhance the ability to expand and acquire water and nutrients in the later stages. Together, they form a continuous and stable underground mycelial network, improving the efficiency of root system in acquiring water and nutrients in barren desert soils. Therefore, the combined use of the two mycorrhizae in this invention exhibits significantly better growth-promoting and stress-resistance effects than single-agent inoculum, demonstrating a significant synergistic effect.

[0022] This invention does not specifically limit the source of the above-mentioned raw materials; commercially available products commonly used in the field are acceptable. In the compound mycorrhizal fertilizer provided by this invention, the compound arbuscular mycorrhizal fungi and compound ectomycorrhizal fungi can expand the absorption range of water and mineral nutrients by plant roots through extra-root hyphae, improve the rhizosphere microenvironment, enhance the plant's ability to acquire water and nutrients, and strengthen the plant's adaptability to adverse conditions such as water restriction and salinity. Specifically, arbuscular mycorrhizal (AM) fungi can form mycorrhizal symbiotic relationships with tree species such as Xinjiang poplar; ectomycorrhizal (ECM) fungi can form ectomycorrhizal symbiotic relationships with pine species such as Scots pine. In this invention, the compound ectomycorrhizal fungicide is composed of mycelial culture masterbatches of Lepista irina FM420 and Lepista nuda FM421, and the compound arbuscular mycorrhizal fungicide is composed of host propagation masterbatches of Funneliformismosseae, Rhizophagus irregularis, and Claroideoglomus claroideum, and is combined with carriers and auxiliary protective components: fermented mycelial residue, peat, vermiculite, humic acid powder, biochar, corn cob powder, and trehalose, thereby improving the adaptability of the fungicide to host plants of different mycorrhizal types, the preservation stability in oasis areas, and the rhizosphere colonization ability.

[0023] In this invention, the weight ratio of the Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus claroideum fungal agents is preferably 1:(0.8~1.2):(0.8~1.2), more preferably 1:(0.9~1.1):(0.9~1.1), and most preferably 1:1:1; the number of effective spores in the compound arbuscular mycorrhizal agent is preferably not less than 100 spores / g, the number of effective propagules is preferably not less than 120 spores / g, and the host root mycorrhizal infection rate is preferably not less than 50%. In this invention, the effective propagules refer to the effective components in the arbuscular mycorrhizal host propagation masterbatch that can form spores, mycelia, and infected root segments that can infect and promote mycorrhizal establishment. In this invention, the Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus claroideum inoculants are obtained through propagation using host plants. The host plants preferably include white clover or red clover. The propagation method preferably includes the following steps: mixing Funneliformis mosseae, Rhizophagus irregularis, or Claroideoglomus claroideum with a propagation substrate, sowing the host plant, cultivating and propagating, pruning the aboveground parts of the host plant, and collecting the propagated material containing arbuscular mycorrhizal spores, mycelium, infected root segments, and rhizosphere substrate to obtain the Funneliformis mosseae, Rhizophagus irregularis, or Claroideoglomus claroideum inoculant. The propagation substrate preferably consists of sand, vermiculite, and peat moss. The preferred mass ratio of sand, vermiculite, and peat moss is 2:1:1. Funneliformis mosseae, Rhizophagus irregularis, or Claroideoglomus claroideum are used in the propagation process. The preferred mass ratio of claroideum to propagation substrate is 5~10:100, more preferably 7~8:100; the preferred temperature for cultivation and propagation is 20~28℃, more preferably 22~26℃; and the preferred cultivation and propagation time is 10~12 weeks, more preferably 11 weeks.

[0024] In this invention, the ectomycorrhizal fungal agent of *Leptochloa chinensis* is *Lepista irina* FM420, and the ectomycorrhizal fungal agent of *Leptochloa nuda* is *Lepista nuda* FM421. The weight ratio of *Lepistairina* FM420 to *Lepista nuda* FM421 is preferably 1:0.8~1.2, more preferably 1:0.9~1.1, and most preferably 1:1. The effective viable count in the compound ectomycorrhizal fungal agent is preferably not less than 1.0 × 10⁻⁶. 8 CFU / g. In this invention, the preferred method for preparing the ectomycorrhizal Lepista irina FM420 or Lepista nuda FM421 inoculum includes the following steps: activating the ectomycorrhizal Lepista irina FM420 or Lepista nuda FM421, inoculating them into MMN liquid medium, and shaking culture to obtain a suspension of Lepista irina FM420 mycelium or Lepista nuda FM421 mycelium, which are the ectomycorrhizal Lepista irina FM420 or Lepista nuda FM421 inoculum; the shaking culture conditions are preferably 23~27℃, 120~140 r / min for 7~15 days, more preferably 24~26℃, 130 r / min for 9~12 days. In this invention, the preferred activation method involves inoculating the preserved bacterial strain onto PDA or MMN medium and activating it at 25±2℃ under light-protected conditions for 7-10 days. Once the colonies are vigorous, the hyphae are white and dense, and free from contamination, the hyphae at the colony edges are selected as inoculation material for further culture. In this invention, the preferred composition of the MMN liquid medium is: 10 g / L glucose, 3 g / L malt extract, 0.5 g / L KH₂PO₄, 0.25 g / L (NH₄)₂HPO₄, 0.15 g / L MgSO₄·7H₂O, 0.025 g / L NaCl, 0.05 g / L CaCl₂, 1.2 mL / L FeCl₃ (1%), and adjusting the pH to 5.5-6.0.

[0025] In the compound mycorrhizal fertilizer of the present invention, the number of viable ectomycorrhizae is preferably not less than 1.0 × 10⁻⁶. 7 CFU / g; In the compound mycorrhizal fertilizer, the number of arbuscular mycorrhizal spores is preferably not less than 12 / g, and the number of propagules is preferably not less than 15 / g; The moisture content of the compound mycorrhizal fertilizer is preferably 20%~35%.

[0026] This invention combines a compound arbuscular mycorrhizal fungicide and a compound ectomycorrhizal fungicide, thus addressing the mycorrhizalization needs of both arbuscular and ectomycorrhizal host plants. When applied to the rhizosphere of *Populus simonii* in Xinjiang, this compound mycorrhizal fertilizer containing effective arbuscular mycorrhizal spores, mycelia, and infected root segments promotes growth under drought stress and increases biomass accumulation. When applied to the rhizosphere of *Pinus sylvestris*, due to the presence of *Lepista irina* FM420 and *Lepista nuda*... FM421 ectomycorrhizal active mycelium can improve the survival rate of Pinus sylvestris under insufficient irrigation conditions and increase biomass. Because mycorrhizal symbiosis improves rhizosphere absorption and plant stress resistance, it can reduce oxidative damage in shelterbelts under drought or insufficient irrigation conditions. Mycorrhizae promote water / nutrient absorption, alleviating water stress and thus improving net photosynthetic rate and water use efficiency. Arbuscular mycorrhizae and ectomycorrhizal mycelium can expand the rhizosphere absorption range, ensuring improved nitrogen absorption and resource utilization. This invention uses fermented mycorrhizal residues, peat, vermiculite, biochar, corn cob powder, trehalose, and other carrier / protective components to optimize the rhizosphere environment in arid areas, enhancing water retention, mycorrhizal preservation, aeration, and drought resistance. Furthermore, this invention uses low-cost carriers such as fermented mycorrhizal residues and corn cob powder to replace high-proportion expensive carriers or decomposed organic fertilizers, reducing production costs and improving applicability for widespread application.

[0027] The present invention also provides a method for preparing the above-mentioned compound mycorrhizal fertilizer, comprising the following steps: mixing fermented mycelium residue, peat, vermiculite, humic acid powder, biochar, corn cob powder and trehalose to obtain a mixture; mixing the mixture with a compound ectomycorrhizal agent under light-protected conditions and a temperature below 30°C; and finally adding a compound arbuscular mycorrhizal agent and mixing under light-protected conditions and a temperature below 30°C to obtain the compound mycorrhizal fertilizer.

[0028] In this invention, the carrier materials include fermented mycelium residue, peat, vermiculite, humic acid powder, biochar, corn cob powder, and trehalose. Preferredly, the carrier materials should be sieved before use, preferably controlling the particle size to 0.5–2.0 mm or passing through a 20–60 mesh sieve. Preferably, the moisture content of the carrier is adjusted to 20%–35%, and the carrier material is sterilized. The sterilization method is preferably pasteurization or low-temperature sterilization, preferably at 60–75°C for 4–8 h, or below 80°C for 2–4 h. After sterilization, the carrier is allowed to cool naturally to room temperature. It is stored only after the material temperature is below 30°C to avoid the high temperature affecting the activity of the inoculum during subsequent mixing. In the preparation method of this invention, all mixing preferably uses low-speed stirring to avoid damaging the arbuscular mycorrhizal spores, mycelia, and infected root segments.

[0029] In the preparation method of this invention, the preferred quality control of the finished product is as follows: the obtained compound mycorrhizal fertilizer should have a uniform color, no obvious lumps, no putrid odor, and no obvious contamination by other microorganisms. Finished product quality testing includes the number of viable ectomycorrhizal bacteria, the number of arbuscular mycorrhizal spores, the number of effective propagules of arbuscular mycorrhizal bacteria, mycorrhizal infection rate, contamination rate, and moisture content. The number of viable ectomycorrhizal bacteria can be detected using the dilution plating method, preferably not less than 1.0 × 10⁻⁶. 7 ~1.0×10 8 CFU / g. The number of arbuscular mycorrhizal spores can be detected by wet sieving decanting-sucrose centrifugation, preferably not less than 50-100 spores / g. The number of effective arbuscular mycorrhizal propagules can be detected by MPN method or pot bioassay. The mycorrhizal infection rate can be detected by root clearing-staining method, preferably not less than 50%-70%. The contamination rate can be detected by plate culture method, preferably not more than 5%. The moisture content of the finished product is preferably controlled at 25%-35%. The above quality indicators are the preferred control ranges for the product of this invention.

[0030] This invention also provides the application of the above-mentioned compound mycorrhizal fertilizer in the establishment of shelterbelts in desert oasis areas, wherein the shelterbelts include Xinjiang poplar shelterbelts, Scots pine shelterbelts, or mixed shelterbelts of Xinjiang poplar and Scots pine.

[0031] In the applications described in this invention, the preferred application scenarios for the compound mycorrhizal fertilizer include: planting young poplar seedlings in arid areas of Xinjiang, establishing shelterbelts, and promoting growth and stress resistance under drought stress; planting young Pinus sylvestris seedlings, establishing farmland shelterbelts, and promoting growth and stress resistance under insufficient irrigation conditions; mixed shelterbelts in arid areas of Xinjiang, oasis shelterbelts, and multi-species ecological establishment. In this invention, the compound mycorrhizal fertilizer is applied by means of root zone application in planting holes or application in trenches around the root zone. The preferred application depth is 5-15 cm, more preferably 8-12 cm. The compound mycorrhizal fertilizer maintains direct contact with the roots or is 2-5 cm away from the main root. Direct mixing with high-concentration fertilizers and pesticides should be avoided. The compound mycorrhizal fertilizer can be evenly spread at the bottom of the planting hole or around the roots, then covered with 3-5 cm of soil. Watering should be done promptly after planting to ensure full contact between the compound mycorrhizal fertilizer and the root zone soil. The preferred application rate of the compound mycorrhizal fertilizer is 80-120 g / plant, more preferably 90-110 g / plant. If used for field crops, the amount should be converted to kg / mu or kg / hm according to the planting density. 2 It is not advisable to simply apply 80-120 g / plant. A schematic diagram illustrating the application method of this invention's compound mycorrhizal fertilizer (AM-ECM compound mycorrhizal fertilizer) to the rhizosphere of planting holes for Populus tomentosa and Pinus sylvestris in Xinjiang is shown below. Figure 1 As shown.

[0032] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0033] Unless otherwise specified, the following embodiments are all conventional methods.

[0034] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0035] The *Funneliformis mosseae*, *Rhizophagus irregularis*, and *Claroideoglomus claroideum* used in the following examples were purchased from the Institute of Root Biology, Yangtze University. The ectomycorrhizal fungi FM420 (*Lepista irina* FM420) and FM421 (*Lepista nuda* FM421) were provided by the Edible Fungi Research Institute, Shanxi Academy of Agricultural Sciences. Their ITS sequences were submitted to GenBank, with accession numbers MK641486 (*Lepista irina* FM420) and MK642877 (*Lepista nuda* FM421), respectively. Fermentation substrate was purchased from Changchun Jinquan Edible Fungi Production Base; peat was purchased from a horticultural substrate manufacturer; vermiculite was purchased from a vermiculite mineral materials manufacturer; humic acid powder was purchased from a humic acid fertilizer manufacturer; biochar was purchased from a biochar manufacturer; corn cob powder was purchased from an agricultural product processing company; and trehalose was purchased from a food additive manufacturer.

[0036] Example 1 Preparation of compound ectomycorrhizal fungi agent (compound ectomycorrhizal fungi agent masterbatch) The preserved ectomycorrhizae Lepista irina FM420 were inoculated onto PDA medium and activated and cultured at 25°C in the dark for 7 days. When the colonies grew vigorously, the hyphae were white and dense and free from contamination, the hyphae at the edge of the colonies were selected as inoculation material for expansion culture. The inoculum material for expansion culture was inoculated into MMN liquid medium (the composition of MMN liquid medium is: glucose 10 g / L, malt extract powder 3 g / L, KH2PO4 0.5 g / L, (NH4)2HPO4 0.25 g / L, MgSO4·7H2O 0.15 g / L, NaCl 0.025 g / L, CaCl2 0.05 g / L, FeCl3 (1%) 1.2 mL / L) at a mass-volume percentage of 4% (i.e., 4 g of inoculum material inoculated into 100 mL of MMN liquid medium). The initial pH of MMN liquid medium was adjusted to 6.3, and the culture was carried out at 25℃ with shaking at 130 r / min for 10 days. The ectomycorrhizal Lepista irina FM420 mycelial suspension was collected to obtain the ectomycorrhizal Lepista irina FM420 inoculum agent (Lepista irina FM420 mycelial culture masterbatch).

[0037] The preserved ectomycorrhizae Lepista nuda FM421 were inoculated onto PDA medium and activated and cultured at 25°C in the dark for 7 days. When the colonies grew vigorously, the hyphae were white and dense and free from contamination, the hyphae at the edge of the colonies were selected as inoculation material for expansion culture. The expanded culture inoculation material was inoculated into MMN liquid medium at a mass-volume percentage of 4% (the composition of MMN liquid medium is: glucose 10 g / L, malt extract powder 3 g / L, KH2PO4 0.5 g / L, (NH4)2HPO4 0.25 g / L, MgSO4·7H2O 0.15 g / L, NaCl 0.025 g / L, CaCl2 0.05 g / L, FeCl3 (1%) 1.2 mL / L). The initial pH of MMN liquid medium was adjusted to 6.3, and the culture was carried out at 25℃ with shaking at 130 r / min for 10 days. The ectomycorrhizal Lepista nuda FM421 mycelial suspension was collected to obtain the ectomycorrhizal Lepista nuda FM421 inoculum (Lepista nudaFM421 mycelial culture masterbatch).

[0038] Ectomycorrhizal fungal agents Lepista irina FM420 and Lepista nuda FM421 were mixed at a mass ratio of 1:1 to obtain a compound ectomycorrhizal fungal agent (compound ectomycorrhizal fungal agent masterbatch). The number of viable bacteria in the compound ectomycorrhizal fungal agent was determined to be no less than 1.0 × 10⁻⁶. 8 CFU / g.

[0039] Example 2 Preparation of compound arbuscular mycorrhizal fungi agent (compound arbuscular mycorrhizal fungi agent masterbatch) Funneliformis mosseae was mixed with a propagation substrate (composed of sterilized sand, vermiculite, and peat moss in a mass ratio of 2:1:1) at a mass percentage of 8:100. After sowing white clover, the mixture was cultured at 22-25℃ for 11 weeks for propagation. After propagation, watering was stopped and the substrate was allowed to dry moderately. The above-ground parts of the white clover were cut off, and the propagation material containing arbuscular mycorrhizal spores, mycelium, infected root segments, and rhizosphere substrate was collected. The material was then dried in the shade at low temperature, crushed, and sieved to obtain Funneliformis mosseae inoculum (Funneliformis mosseae host propagation masterbatch).

[0040] Rhizophagus irregularis was mixed with a propagation substrate (composed of sterilized sand, vermiculite, and peat moss in a mass ratio of 2:1:1) at a mass percentage of 8:100. After sowing white clover, the mixture was cultured at 22-25℃ for 11 weeks for propagation. After propagation, watering was stopped and the substrate was allowed to dry moderately. The above-ground parts of the white clover were cut off, and the propagation material containing arbuscular mycorrhizal spores, mycelium, infected root segments, and rhizosphere substrate was collected. The material was then air-dried at low temperature, pulverized, and sieved to obtain Rhizophagus irregularis inoculant (Rhizophagus irregularis host propagation masterbatch).

[0041] Claroideoglomus claroideum was mixed with a propagation substrate (composed of sterilized sand, vermiculite, and peat moss in a mass ratio of 2:1:1) at a mass percentage of 8:100. After sowing white clover, the mixture was cultured at 22-25℃ for 11 weeks for propagation. After propagation, watering was stopped and the substrate was allowed to dry moderately. The above-ground parts of the white clover were cut off, and the propagation material containing arbuscular mycorrhizal spores, mycelium, infected root segments, and rhizosphere substrate was collected. The material was then dried in the shade at low temperature, crushed, and sieved to obtain Claroideoglomus claroideum inoculum (Claroideoglomus claroideum host propagation masterbatch).

[0042] Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus claroideum fungal inoculants were mixed at a mass ratio of 1:1:1 to obtain a compound arbuscular mycorrhizal fungal inoculant (compound arbuscular mycorrhizal fungal inoculant masterbatch). The results showed that the compound arbuscular mycorrhizal fungal inoculant contained at least 100 effective spores / g, at least 120 effective propagules / g, and a host root mycorrhizal infection rate of at least 50%.

[0043] Example 3 A compound mycorrhizal fertilizer (AM-ECM compound mycorrhizal fertilizer) suitable for shelterbelt construction in desert oasis areas is made from the following raw materials: 12.5 kg of compound arbuscular mycorrhizal agent, 12.5 kg of compound ectomycorrhizal agent, 25 kg of fermented mycorrhizal fungus, 18 kg of peat, 10 kg of vermiculite, 4 kg of humic acid powder, 4 kg of biochar, 13 kg of corn cob powder, and 1 kg of trehalose; the compound arbuscular mycorrhizal agent was prepared in Example 2; the compound ectomycorrhizal agent was prepared in Example 1.

[0044] The preparation method of the compound mycorrhizal fertilizer is as follows: The fermentation starter culture, peat, vermiculite, humic acid powder, biochar, corn cob powder, and trehalose were sieved separately to control the particle size to 0.5–2.0 mm. These components were then mixed to obtain a final mixture. The moisture content of the mixture was adjusted to 25%, and then sterilized at 75°C for 4 hours. After sterilization, the mixture was allowed to cool naturally to room temperature. It was stored until the temperature of the mixture was below 30°C to avoid the high temperature affecting the activity of the microbial agent during subsequent mixing.

[0045] Mix the mixture with the compound ectomycorrhizal fungal agent under the conditions of ambient temperature below 30℃ and in a dark and clean environment. Stir at low speed for 8 minutes, then add the compound arbuscular mycorrhizal fungal agent and continue stirring at low speed for 8 minutes (the purpose of low-speed stirring is to avoid damaging the ectomycorrhizal hyphae, arbuscular mycorrhizal spores, hyphae and infected root segments) to obtain the compound mycorrhizal fertilizer. Control the moisture content of the compound mycorrhizal fertilizer to 30%, pack it into a light-proof packaging bag, and store it under cool and dry conditions.

[0046] The flowchart of the above preparation process is as follows: Figure 2 As shown.

[0047] Example 4 A compound mycorrhizal fertilizer suitable for establishing shelterbelts in desert oasis areas is made from the following raw materials: 10 kg of compound arbuscular mycorrhizal agent, 15 kg of compound ectomycorrhizal agent, 20 kg of fermented mycorrhizal residue, 15 kg of peat, 8 kg of vermiculite, 2 kg of humic acid powder, 2 kg of biochar, 10 kg of corn cob powder, and 0.5 kg of trehalose; the compound arbuscular mycorrhizal agent was prepared in Example 2; the compound ectomycorrhizal agent was prepared in Example 1.

[0048] The preparation method is the same as in Example 3.

[0049] Example 5 A compound mycorrhizal fertilizer suitable for shelterbelt construction in desert oasis areas of Xinjiang Uygur Autonomous Region, China, is made from the following raw materials: 10 kg of compound arbuscular mycorrhizal agent, 5 kg of compound ectomycorrhizal agent, 30 kg of fermented mycorrhizal residue, 21 kg of peat, 12 kg of vermiculite, 6 kg of humic acid powder, 6 kg of biochar, 16 kg of corn cob powder, and 1.5 kg of trehalose; the compound arbuscular mycorrhizal agent was prepared in Example 2; the compound ectomycorrhizal agent was prepared in Example 1.

[0050] The preparation method is the same as in Example 3.

[0051] Experimental Example 1 The compound mycorrhizal fertilizer obtained in Example 3 was tested as follows: 1. pH measurement Weigh 10 g of the compound mycorrhizal fertilizer sample, add 90 mL of deionized water, shake for 30 min and let stand for 10 min, and use a calibrated pH meter (PHS-3C type) to measure the pH value of the suspension.

[0052] 2. EC value determination Weigh 10 g of the compound mycorrhizal fertilizer sample, add 90 mL of deionized water, shake for 30 min and filter. Measure the conductivity (EC) of the filtrate using a conductivity meter. The result is expressed as mS / cm.

[0053] 3. Moisture content determination The drying loss method was used. Approximately 5 g of compound mycorrhizal fertilizer was weighed and dried at 105℃ to constant weight. The moisture content (%) was calculated using the following formula: Moisture content (%) = (W1-W2) / W1×100; where W1 is the initial mass of the sample (g) and W2 is the mass after drying (g).

[0054] 4. Determination of contamination rate The plate dilution and spread method was used. 10 g of the compound mycorrhizal fertilizer was added to 90 mL of sterile water to prepare a suspension, which was then serially diluted and spread onto PDA and bacterial culture media. After incubation at 25℃ for 7 days, the contamination rate (%) was calculated as follows: contamination rate (%) = (number of contaminating colonies / total number of colonies) × 100.

[0055] Viability retention rate after 3 months of storage at 5.4℃ The compound mycorrhizal fertilizer was sealed and stored at 4℃ for 3 months. The number of viable bacteria before and after storage was determined by plate count method. Viable bacteria retention rate (%) = number of viable bacteria after storage / initial number of viable bacteria × 100.

[0056] Viability retention rate after storage at 6.4℃ for 6 months The testing method is the same as above. The storage period is 6 months.

[0057] 7. Viable bacteria retention rate after 3 months of storage at room temperature Store at 25±2℃ protected from light for 3 months. Viable cell count was used for determination.

[0058] 8. Viable bacterial retention rate after 6 months of storage at room temperature The method is the same as above. Storage time is 6 months.

[0059] 9. Ectomycorrhizal (ECM) mycelium regains its growth ability Take 0.5 g of the preserved compound mycorrhizal fertilizer and inoculate it onto an MMN medium plate. Incubate at 25℃ for 7 days.

[0060] Determine the growth rate of colony diameter or mycelial growth rate: Recovery growth rate (%) = Colony diameter after preservation / Colony diameter of fresh inoculum × 100.

[0061] 10. Effective viable bacteria count of finished product ECM The dilution plating method was used for colony formation. 10 g of the compound mycorrhizal fertilizer sample was added to 90 mL of sterile water and shaken to mix. After serial dilution, the sample was inoculated onto MMN medium. The culture was carried out at 25℃ for 10 days. Colony forming units (CFU) were counted. Results are expressed as CFU / g.

[0062] 11. Number of effective spores in arbuscular mycorrhizal (AM) Wet sieving and decanting combined with sucrose centrifugation was used.

[0063] Weigh 50 g of sample. Pass the sample through 500 μm, 250 μm, 100 μm, and 45 μm sieves sequentially. After recovering the AM spores, count them under a stereomicroscope. The results are expressed as spores / g.

[0064] 12. AM effective breeding number The Most Probable Number (MPN) method was used. The bacterial agent was serially diluted and inoculated into the corn trap system. Infection status was assessed after 6 weeks of incubation. Results were calculated based on the MPN statistics and expressed as cells / g.

[0065] 13. AM infectivity The pot inoculation method was used. Clover seedlings were inoculated with the inoculum. After 45 days of cultivation, roots were harvested. The roots were stained with 10% KOH for clearing and then with acid fuchsin. The hyphae, vesicles, and arbuscular structures were observed under a microscope.

[0066] Calculated according to the method of Phillips & Hayman (1970): AM infection rate (%) = number of infected root segments / total number of investigated root segments × 100.

[0067] The results, shown in Table 1, indicate that the compound mycorrhizal fertilizer prepared in this invention possesses excellent physicochemical properties, biological activity, and storage stability. The product maintains a high survival rate of viable bacteria under both low and normal temperature conditions. Simultaneously, the ECM mycelium exhibits strong recovery and growth ability, while the AM fungi maintain a high number of effective spores, propagules, and infectivity. This demonstrates that the compound mycorrhizal fertilizer prepared in this invention can effectively maintain the activity of the fungal agent, possesses a good shelf life and mycorrhizal colonization ability, and provides a reliable guarantee for subsequently promoting the growth of Xinjiang poplar and Scots pine, improving water and fertilizer use efficiency, and enhancing stress resistance.

[0068] Table 1 Test Results

[0069] Experimental Example 2 The effect of the compound mycorrhizal fertilizer obtained in Example 3 on the growth of Populus tomentosa in Xinjiang under normal water supply conditions The test plant was a one-year-old poplar sapling from Xinjiang. The experimental site was the Jiamu Experimental Station in Wensu County, Aksu Prefecture, Xinjiang Uygur Autonomous Region, China. The soil at the experimental site was silty loam with a pH of 8.5, total nitrogen of 0.26 g / kg, and available nitrogen of 16.67 mg / kg. Two treatments were established: normal water supply without the compound mycorrhizal fertilizer obtained in Example 3 (CK) and normal water supply with the compound mycorrhizal fertilizer obtained in Example 3 (CK+F). Under normal water supply conditions, the soil volumetric moisture content was controlled at 17%–20%. v The compound mycorrhizal fertilizer obtained in Example 3 was applied to the rhizosphere at planting time, 90 g per plant, at a depth of 10 cm, with the compound mycorrhizal fertilizer 3 cm away from the main root; each treatment had 3 replicate plots. The above compound mycorrhizal fertilizer was applied in early April, and then the following tests were conducted in mid-October: (1) Plant height A steel tape measure was used for measurement. The vertical height from the ground surface to the growing point of the terminal bud of the plant was measured, accurate to 0.1 cm. At least 10 seedlings were randomly selected from each treatment for measurement, and the average value was taken.

[0070] (2) Crown width A steel tape measure was used for measurement. The maximum width of the tree crown in the east-west and north-south directions was measured separately. Crown width (cm) = (east-west crown width + north-south crown width) / 2. At least 10 seedlings were randomly selected for each treatment for measurement.

[0071] (3) Ground diameter The diameter of the main stem of the seedling was measured using a digital vernier caliper at a height of 5 cm above the ground, accurate to 0.01 mm. At least 10 seedlings were randomly selected from each treatment for measurement.

[0072] (4) Biomass After harvesting, the plants are separated into aboveground and underground parts. The roots are washed with clean water to remove any soil adhering to them. After blanching at 105℃ for 30 minutes, the roots are dried at 75-85℃ until constant weight. The dry weight is then measured. Total biomass: Total biomass = aboveground dry weight + underground dry weight, unit: g / plant.

[0073] (5) H2O2 (hydrogen peroxide) content The absorbance was determined using the titanium dioxide colorimetric method or a commercial reagent kit. 0.5 g of fresh leaves were ground in liquid nitrogen and then extracted with acetone. After centrifugation, the supernatant was collected and titanium dioxide was added for color development. The absorbance was measured at 415 nm.

[0074] The H₂O₂ content was calculated based on the standard curve. The results are expressed as μmol / g FW (fresh weight) or nmol / g FW. (6) O2 - (Superoxide anion) production rate The hydroxylamine oxidation method was used for determination. 0.5 g of fresh leaves were extracted by grinding with phosphate buffer. The extracted nitrite was generated upon reaction with hydroxylamine hydrochloride. Sulfonic acid and α-naphthylamine were added for color development. The absorbance was measured at 530 nm. O2 was calculated based on the NaNO2 standard curve. - Production rate. The result is expressed as nmol·min⁻¹ -1 ·g -1 FW or μmol·g -1 FW.

[0075] The methods for detecting spore density and mycorrhizal infection rate are the same as those for Experiment 1.

[0076] The results are shown in Table 2. Under normal water supply conditions, the compound mycorrhizal fertilizer of the present invention can promote the colonization of rhizosphere mycorrhizae in Xinjiang poplar, increase the density of rhizosphere spores, and promote the accumulation of plant height, crown width and biomass.

[0077] Table 2. Effects of the compound mycorrhizal fungal fertilizer of the present invention on the growth of Populus alba in Xinjiang under normal water supply conditions.

[0078] Experimental Example 3 The effects of the compound mycorrhizal fertilizer obtained in Example 3 on drought resistance and growth promotion of Populus tomentosa in Xinjiang under drought stress Two treatments were established: one under drought stress without the application of the compound mycorrhizal fungal fertilizer obtained in Example 3 (DS), and the other under drought stress with the application of the same fertilizer (DS+F). Soil volumetric moisture content was controlled at 10%–13% under drought stress conditions. v The mycorrhizal fertilizer was applied to the root zone at planting time, 90 g per plant. The compound mycorrhizal fertilizer was applied in early April. Except for WUE and Pn, which were measured in July and mid-October of the same year, all other indicators were measured on October 15th of the same year. (1) Measurement of net photosynthetic rate (Pn) A portable photosynthesis measurement system (LI-6800, USA) was used for measurement. On a clear, cloudless day, measurements were taken at 10:00 AM on healthy functional leaves in the upper and middle parts of the plant. The environmental conditions in the leaf chamber were kept consistent during the measurement, and the net photosynthetic rate (Pn) of the leaves was recorded.

[0079] (2) Measurement of water use efficiency (WUE) Instantaneous water use efficiency (WUE) of leaves is calculated using net photosynthetic rate (Pn) and transpiration rate (Tr). The formula is: WUE = Pn / Tr.

[0080] (3) Nitrogen Use Efficiency (NUE) Measurement The Kjeldahl method was used to determine the nitrogen content of the plants. The calculation formula is: NUE (%) = (nitrogen accumulation in nitrogen-treated plants - nitrogen accumulation in plants without nitrogen treatment) / nitrogen application rate × 100%.

[0081] The detection methods for the remaining factors are the same as in Experiment 2.

[0082] The results are shown in Table 3, ranging from 10% to 13%. V Under drought stress, the compound mycorrhizal fertilizer of this invention can still maintain a high level of mycorrhizal colonization, promote the growth of Xinjiang poplar, and reduce O2. - The increased levels of Pn, WUE, and NUE indicate that it can alleviate drought-induced oxidative damage; the increased levels of Pn, WUE, and NUE indicate that it can improve photosynthetic function, water use, and nitrogen use capacity.

[0083] Table 3. Effects of the compound mycorrhizal fungi fertilizer of the present invention on drought resistance and growth promotion of Populus alba in Xinjiang under drought stress.

[0084] Test Example 4 The effect of the compound mycorrhizal fertilizer obtained in Example 3 on the establishment effect of Pinus sylvestris under fully irrigated conditions The test plants were two-year-old juvenile Pinus sylvestris. Two treatments were established: one with full irrigation but without the compound mycorrhizal fertilizer obtained in Example 3 (FI), and the other with full irrigation and application of the same compound mycorrhizal fertilizer (FI+F). Under full irrigation conditions, the soil volumetric moisture content was controlled at 17%–20%. v The compound mycorrhizal fertilizer obtained in Example 3 was applied to the rhizosphere at the time of planting, 90 g per plant; each treatment had 3 replicate plots.

[0085] The microbial fertilizer was applied on April 3rd. On October 15th of the same year, the indicators listed in Table 4 were tested on both groups using the same methods as in Experiment 2. The results are shown in Table 4, indicating that under fully irrigated conditions, the compound mycorrhizal fertilizer of this invention can increase the mycorrhizal infection rate of Pinus sylvestris, promote plant height, crown width, and biomass accumulation, and reduce O2. - content.

[0086] Table 4. Effects of the compound mycorrhizal fungal fertilizer of the present invention on the planting effect of Pinus sylvestris under fully irrigated conditions.

[0087] Experimental Example 5 Effects of the compound mycorrhizal fertilizer obtained in Example 3 on the stress resistance and establishment effect of Pinus sylvestris under insufficient irrigation conditions Two treatments were set up: one without full irrigation and without applying the compound mycorrhizal fungal fertilizer obtained in Example 3 (DI), and another with full irrigation and applying the same compound mycorrhizal fungal fertilizer (DI+F). Under the full irrigation condition, the soil volumetric moisture content was controlled at 12%–15%. v A constant pressure drip irrigation system is used for precise water replenishment, combined with TDR soil moisture sensor monitoring; microbial fertilizer is applied to the root zone at the time of planting, 90g per plant.

[0088] The indicators shown in Table 5 were tested for both groups (the microbial fertilizer was applied on April 3rd; except for WUE and Pn, which were measured in July and mid-October of the same year, the other indicators were measured on October 15th of the same year). The testing method was the same as in Experiment 3, and the results are shown in Table 5, ranging from 12% to 15%. v Under conditions of insufficient irrigation, the compound mycorrhizal fertilizer of this invention significantly improved the mycorrhizal infection rate, growth indicators, and biomass accumulation of Pinus sylvestris, with a biomass increase of 40.20%; at the same time, it reduced O2. - The compound mycorrhizal fertilizer of this invention, along with H2O2, increases Pn and WUE. While the nitrogen accumulation in Pinus sylvestris increases, the NUE does not show a significant difference, indicating that the compound mycorrhizal fertilizer of this invention has the effect of improving nitrogen absorption or nitrogen accumulation.

[0089] Table 5. Effects of the compound mycorrhizal fungi fertilizer of the present invention on the stress resistance and establishment effect of Pinus sylvestris under insufficient irrigation conditions.

[0090] Experimental Example 6 Application scheme of the compound mycorrhizal fertilizer obtained in Example 3 in the mixed shelterbelt of poplar and Pinus sylvestris in Xinjiang The design of each group is shown in Table 6. The microbial fertilizer in the table refers to the compound mycorrhizal fertilizer obtained in Example 3.

[0091] Table 6 Group Design

[0092] The indicators listed in Table 7 were tested for different groups using the same methods as in Experiment 3, and the results are shown in Table 7.

[0093] Table 7. Application effect of the compound mycorrhizal fungi fertilizer of the present invention in the mixed shelterbelt of poplar and Pinus sylvestris in Xinjiang.

[0094] Note: Different lowercase letters indicate significant differences between treatments (P<0.05).

[0095] Experimental Example 7 Existing solution: The existing root-promoting technology for Pinus sylvestris uses a mixture of fungal inoculant and substrate, which is then applied through holes. At the same time, indolebutyric acid (IBA) rooting solution is applied to the southwest and northeast sides of the trunk. This method is mainly used to promote the rooting of large container seedlings of Pinus sylvestris in winter landscapes.

[0096] The differences between the technical solution of this invention and the existing solution are shown in Table 8. It can be seen that the existing technology mainly solves the problem of promoting root growth in large container seedlings of Pinus sylvestris and relies on the binary interaction between mycorrhizal fungi and indolebutyric acid. This invention does not rely on exogenous hormones and can be adapted to different mycorrhizal types of shelterbelt tree species such as Populus tomentosa and Pinus sylvestris. It is more suitable for shelterbelt construction and drought resistance and growth promotion in arid areas of Xinjiang.

[0097] Table 8. Differences between the present invention and prior art solutions

[0098] Experimental Example 8 The difference from Experimental Example 2 is that the applied microbial fertilizer is the compound arbuscular mycorrhizal fungicide obtained in Example 2, while the rest are the same as Experimental Example 2.

[0099] The results of Experiment 8 and Experiment 2 were tested for each of the indicators in Table 9 below, and the results are shown in Table 9.

[0100] Table 9 Comparison of results between Experiment 8 and Experiment 2

[0101] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A compound mycorrhizal fertilizer suitable for establishing shelterbelts in desert oasis areas, characterized in that, The mixture comprises the following raw materials by weight: 10-15 parts of compound arbuscular mycorrhizal fungal agent, 5-15 parts of compound ectomycorrhizal fungal agent, 20-30 parts of fermented substrate, 15-21 parts of peat, 8-12 parts of vermiculite, 2-6 parts of humic acid powder, 2-6 parts of biochar, 10-16 parts of corn cob powder, and 0.5-1.5 parts of trehalose; the compound arbuscular mycorrhizal fungal agent is composed of Funneliformis mosseae fungal agent, Rhizophagus irregularis fungal agent, and Claroideoglomus claroideum fungal agent, and the compound ectomycorrhizal fungal agent is composed of ectomycorrhizal fungi of *Tricholoma matsutake* and ectomycorrhizal fungi of *Tricholoma lilacinus*.

2. The compound mycorrhizal fertilizer according to claim 1, characterized in that, The weight ratio of the Funneliformis mosseae fungal agent, Rhizophagus irregularis fungal agent, and Claroideoglomus claroideum fungal agent is 1:(0.8~1.2):(0.8~1.2); the number of spores in the compound arbuscular mycorrhizal fungal agent is not less than 100 / g, the number of propagules is not less than 120 / g, and the host root mycorrhizal infection rate is not less than 50%.

3. The compound mycorrhizal fertilizer according to claim 1, characterized in that, The ectomycorrhizal fungal agent for *Leptochloa crus-galli* is *Lepista irina* FM420, and the ectomycorrhizal fungal agent for *Leptochloa nuda* is *Lepista nuda* FM421. The weight ratio of *Lepista irina* FM420 to *Lepista nuda* FM421 is 1:0.8~1.2; the viable count in the compound ectomycorrhizal fungal agent is not less than 1.0 × 10⁻⁶. 8 CFU / g.

4. The compound mycorrhizal fertilizer according to claim 1, characterized in that, In the compound mycorrhizal fertilizer, the number of viable ectomycorrhizae is not less than 1.0 × 10⁻⁶. 7 CFU / g; the compound mycorrhizal fertilizer contains at least 12 spores / g and at least 15 vegetative cells / g of arbuscular mycorrhizae; the moisture content of the compound mycorrhizal fertilizer is 20%~35%.

5. The compound mycorrhizal fertilizer according to claim 1, characterized in that, The fungal agents Funneliformis mosseae, Rhizophagus irregularis, and Claroideoglomus claroideum were obtained by propagation from host plants; the host plants included white clover or red clover.

6. The compound mycorrhizal fertilizer according to claim 5, characterized in that, The propagation method includes the following steps: mixing Funneliformis mosseae, Rhizophagus irregularis, or Claroideoglomus claroideum with a propagation substrate, sowing host plants, cultivating and propagating, cutting off the aboveground parts of the host plants, and collecting the propagated material containing arbuscular mycorrhizal spores, mycelia, infected root segments, and rhizosphere substrate to obtain Funneliformis mosseae, Rhizophagus irregularis, or Claroideoglomus claroideum inoculants; the propagation substrate is composed of sand, vermiculite, and peat; the mass ratio of sand, vermiculite, and peat is 2:1:1; the mass ratio of Funneliformis mosseae, Rhizophagus irregularis, or Claroideoglomus claroideum to the propagation substrate is 5~10:100; the cultivation and propagation temperature is 20~28℃, and the cultivation and propagation time is 10~12 weeks.

7. The compound mycorrhizal fertilizer according to claim 3, characterized in that, The preparation method of the ectomycorrhizal Lepistairina FM420 inoculant or ectomycorrhizal Lepista nuda FM421 inoculant includes the following steps: activating ectomycorrhizal Lepista irina FM420 or ectomycorrhizal Lepista nuda FM421 respectively, inoculating them into MMN liquid medium, and shaking culture to obtain ectomycorrhizal Lepista irina FM420 mycelial suspension or ectomycorrhizal Lepista nuda FM421 mycelial suspension, which are ectomycorrhizal Lepista irina FM420 inoculant or ectomycorrhizal Lepista nuda FM421 inoculant; the shaking culture conditions are 23~27℃, 120~140 r / min, and culture for 7~15 days.

8. The method for preparing the compound mycorrhizal fertilizer according to any one of claims 1 to 7, characterized in that, The process includes the following steps: mixing fermented bacterial residue, peat, vermiculite, humic acid powder, biochar, corn cob powder, and trehalose to obtain a mixture; mixing the mixture with a compound ectomycorrhizal fungicide under light-protected conditions and a temperature below 30°C; and finally adding a compound arbuscular mycorrhizal fungicide under light-protected conditions and a temperature below 30°C to obtain a compound mycorrhizal fertilizer.

9. The application of the compound mycorrhizal fertilizer according to any one of claims 1 to 7 in the establishment of protective forests in desert oasis areas, characterized in that, The shelterbelts include Xinjiang poplar shelterbelts, Scots pine shelterbelts, or mixed shelterbelts of Xinjiang poplar and Scots pine.

10. The application according to claim 9, characterized in that, The compound mycorrhizal fertilizer is applied in the root zone of the planting hole or in a trench around the root zone, at a depth of 5-15 cm. The compound mycorrhizal fertilizer is in direct contact with the roots or 2-5 cm away from the main root. The application amount of the compound mycorrhizal fertilizer is 80-120 g / plant.

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