A planting method for simultaneously improving soil health and crop yield in saline-alkali soil

Abstract

This invention discloses a planting method that simultaneously improves soil health and crop yield in saline-alkali land. The method includes the following steps: mixing Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus mucilaginosus to prepare a compound microbial agent; mixing the compound microbial agent with chemical fertilizer to prepare a base fertilizer; applying the base fertilizer to the side and below the crop seeds during the sowing period; and delivering a microbial activator; after the crops mature, replanting legumes and cruciferous crops; harvesting the above-ground parts of the cruciferous crops for silage; crushing the legumes during frost and covering the ground; and repeating this cycle year-round. This invention integrates three technologies—microbial agent stress resistance, drip irrigation activation, and tiered green manure management—to achieve seasonal improvement and high yield in moderately saline-alkali land (salt content > 0.6%), increase available soil nutrients, improve soil fertility, and enhance spring wheat yield and grain quality, thus achieving a dual improvement in soil health and crop yield.

Description

Technical Field

[0001] This invention relates to planting methods, and more particularly to a planting method that simultaneously improves soil health and crop yield in saline-alkali land. Background Technology

[0002] The Yellow River irrigation area is an important grain production belt in Northwest my country, with slightly to moderately saline-alkali land (salt content 0.1%-0.6%) accounting for more than 70% of the total cultivated land area. Although this type of land has basic cultivation conditions, it has long faced hidden problems such as aggravated secondary salinization, soil compaction, and nutrient imbalance. Under traditional planting methods, farmers often rely excessively on chemical fertilizers (an average annual nitrogen application of up to 200 kg / ha) to maintain spring wheat yields, leading to a sharp decline in soil microbial diversity, organic matter content hovering below 1.0 g / kg, and a gradual worsening of salt accumulation on the surface. Even more serious is the fact that the summer exposure period after spring wheat harvest (July-September) coincides with the high-temperature evaporation season, accelerating the rise of topsoil salinity and creating a vicious cycle of "low yield - increased fertilization - salinization". Existing improvement technologies have significant limitations: most microbial agents use only Bacillus subtilis, which can not maintain its activity for more than 30 days in mild to moderate saline-alkali environments and lacks ion-specific regulation capabilities; although the application of green manure is advocated, the nitrogen fixation efficiency of single-sowing hairy vetch is limited (about 30 kg N / ha), while single-sowing cruciferous green manure is difficult to effectively suppress salt due to its low biomass (<2 tons / acre); although drip irrigation technology can control salt, conventional drip irrigation tape buried at a shallow depth of 5 cm is easily blocked by salt crystals and does not form a synergy with the maintenance of microbial activity. Summary of the Invention

[0003] In view of this, the present invention proposes a planting method that simultaneously improves soil health and crop yield in saline-alkali land. Through the precise coupling of biological, physical and agronomic measures, the method can block the soil degradation process while ensuring the yield of the current season, thereby achieving sustainable yield improvement.

[0004] The planting method provided by this invention, which simultaneously improves soil health and crop yield in saline-alkali land, includes the following steps:

[0005] (1) Bacillus subtilis, Bacillus amyloliquefaciens and Bacillus spp. were respectively adjusted to an OD600 of 0.4-0.6 using liquid culture medium and mixed to prepare a compound microbial agent; the compound microbial agent was then mixed with chemical fertilizer to prepare a base fertilizer;

[0006] (2) During the crop sowing period, the base fertilizer is applied to the side and below the crop seeds; during the crop jointing stage and grain filling stage, the microbial activator is delivered using a drip irrigation system; the microbial activator contains 30-40 g / L of trehalose and 20-30 g / L of humic acid;

[0007] (3) After the crop matures, the straw of the crop is crushed to ≤5cm and returned to the field, and legumes and cruciferous crops are replanted; the above-ground parts of the cruciferous crops are harvested for silage; the legumes are crushed and covered with soil during the frost period; this is carried out in an annual cycle.

[0008] Preferably, in step (1), the bacterial suspensions of Bacillus subtilis, Bacillus amyloliquefaciens and Bacillus spp. are mixed in a volume ratio of (0.9-1.1):(0.9-1.1):(0.9-1.1).

[0009] Preferably, the fertilizer in step (1) is a nitrogen-reducing fertilizer; the nitrogen-reducing fertilizer includes urea and superphosphate; the mass ratio of the compound microbial agent to the nitrogen-reducing fertilizer is 1:5 to 1:6.3.

[0010] Preferably, the nitrogen-reducing fertilizer is a fertilizer with a nitrogen reduction of 20-30%; the urea (8-10 kg / mu), the superphosphate (8-10 kg / mu), and the compound microbial agent (3-4 kg / mu) are mixed and applied.

[0011] Preferably, in step (2), the microbial activator is prepared from the following components at the following concentrations: trehalose 30-40 g / L, humic acid 20-30 g / L and potassium dihydrogen phosphate 4-6 g / L, with a pH of 6.5-7.0.

[0012] Preferably, in step (2), the microbial activator is delivered using a drip irrigation system at a rate of 0.5 g / L to 1.0 g / L within 24 hours after irrigation during the crop jointing stage, and this is continued for 1 to 2 hours; and the microbial activator is delivered using a drip irrigation system at a rate of 0.5 g / L to 1.0 g / L on the day of irrigation during the crop grain filling stage, and this is continued for 1 to 2 hours.

[0013] Preferably, in step (3), the legume crop is hairy vetch; the cruciferous crop is rapeseed; the planting density ratio of hairy vetch to rapeseed is 2.5:1-3.5:1. The sowing amount of hairy vetch is 3-4 kg / mu; the sowing amount of rapeseed is 0.2-0.5 kg / mu.

[0014] Preferably, the crop is wheat; the wheat is the spring wheat variety Yongliang No. 4.

[0015] Preferably, improving the health of saline-alkali soil involves improving one or more of the following indicators: reducing the soil sodium adsorption ratio, increasing organic matter content, increasing total nitrogen content, reducing soil pH, increasing soil carbon, nitrogen, phosphorus enzyme activity, or increasing soil residual carbon content.

[0016] Preferably, the increase in soil carbon, nitrogen, phosphorus enzyme activity is achieved by increasing the activity of one or more of the following enzymes: β-glucosidase, xylanase, cellobiase, leucine aminopeptidase, chitinase, or alkaline phosphatase.

[0017] The increase in soil residual carbon content refers to increasing the carbon content of one or more of the following: bacterial residual carbon, fungal residual carbon, microbial residual carbon, or plant residual carbon.

[0018] To address soil degradation and yield bottlenecks in mildly to moderately saline-alkali land (salt content 0.1%-0.6%) along the Yellow River irrigation area, this invention proposes a synergistic improvement method integrating microorganisms, water and salt, and green manure. Through three major technological innovations—targeted activation of functional microbial agents, dynamic salt control via drip irrigation systems, and spatiotemporal optimization of green manure resources—this method achieves a simultaneous leap in soil health and spring wheat yield. The specific scheme is as follows:

[0019] 1. Functional modular microbial agents

[0020] Composite microbial community design: Bacillus subtilis ACCC 11025, Bacillus amyloliquefaciens ACCC 19743, and Bacillus colloidis ACCC 10013 were selected. Each strain was cultured for 3 days at 30℃ and 150 rpm in TSB liquid medium with shaking. Cells were then collected at room temperature (8,000 r / min, 5 min) and resuspended in TSB liquid medium to OD. 600 The concentration was 0.4-0.6, and finally, a compound microbial agent was prepared by mixing the components at a volume ratio of (0.9-1.1):(0.9-1.1):(0.9-1.1). The TSB liquid culture medium was prepared using tryptone (17.0 g / L), soybean peptone (3.5 g / L), sodium chloride (5.0 g / L), dipotassium hydrogen phosphate (2.5 g / L), and glucose (2.5 g / L), with a pH of 7.3±0.2.

[0021] Application method: Mix the prepared compound microbial inoculant with reduced-volume fertilizer (nitrogen fertilizer reduced by 20%-30%) as base fertilizer, at a rate of 3-4 kg / mu, ensuring that the rhizosphere microbial colonization density is ≥10. 5 CFU / g.

[0022] 2. Drip irrigation, fertilization, and bacteria integrated system

[0023] The drip irrigation tape is buried at a depth of 8-12 cm (avoiding the surface salt crystal layer), and the dripper spacing is 30 cm; 0.5 g / L of microbial activator (prepared from 30-40 g / L trehalose, 20-30 g / L humic acid and 4-6 g / L potassium dihydrogen phosphate, pH 6.5-7.0) is added to the irrigation water.

[0024]

[0025] Applying microbial activators 2-3 days after irrigation during the jointing stage, with a duration of 1-2 hours, offers the following benefits: ① During the jointing stage, vegetative growth is vigorous, stem and node cells are actively dividing, making them sensitive to water, nutrients, and exogenous regulators. ② On the first day of irrigation, the soil is saturated, pores are filled with water, and the root system is in an "adaptation period," resulting in lower absorption efficiency. On the second day, soil moisture drops to 70%-80% of field capacity (optimal range), improving soil aeration, enhancing root respiration, and reaching peak absorption capacity. The activator can then be evenly diffused into the densely rooted area with the water. ③ 1-2 hours ensures sufficient saturation of the root layer, allowing the crop to fully absorb the activator. Exceeding 2 hours may result in the activator being fixed by the soil (e.g., adsorbed by clay) or degraded by microorganisms.

[0026] Administering microbial activators on the first 1-2 days of irrigation during the grain-filling stage, with a duration of 1-2 hours, offers the following benefits: ① The grain-filling stage is the core phase of crop reproductive growth and dry matter accumulation, and a sensitive period for water and nutrients. ② The grain-filling stage coincides with periods of high temperatures, strong transpiration, and rapid soil moisture consumption. On the first day of irrigation, after drought and subsequent re-irrigation, the root system's water absorption capacity reaches its peak within 24 hours. ③ Lateral diffusion occurs within three hours, covering the root zone and continuously stimulating the synthesis of photosynthetic products.

[0027] 3. Spatial and temporal hierarchical management of green manure

[0028] Leguminous green manure (hairy vetch) and cruciferous green manure (forage rape) are mixed and sown at a planting density ratio of 2.5:1 to 3.5:1 (sowing rate: hairy vetch 3-4 kg / mu + rape 0.2-0.5 kg / mu). This approach takes into account the following: hairy vetch: deep root system (>1.5 m) to draw groundwater, lower the water level to prevent salinization, and fix nitrogen up to 45 kg N / ha; forage rape: shallow root system (<0.3 m) to secrete glucosinolates, inhibit the accumulation of salt on the surface of 0-30 cm, and increase biomass to 2.8 tons / mu.

[0029] Staged harvesting strategy: Early October: Harvest the above-ground parts of rapeseed (accounting for 70% of biomass) for silage; Frost period: Crush hairy vetch to cover the ground surface, forming a 5 cm organic salt barrier layer, reducing the rate of salt rise in winter by 40%.

[0030] 4. Collaborative Loop Mode

[0031] Before spring sowing the following year, the land was plowed to a depth of 25cm using a combined tillage machine to integrate the green manure stubble (nitrogen content 1.2%-1.8%) with the mulch into the soil.

[0032] Beneficial effects:

[0033] This invention achieves a synergistic breakthrough in the treatment of mild to moderate saline-alkali land along the Yellow River irrigation area, resulting in improved soil health, increased crop yield, and enhanced resource recycling efficiency. It utilizes functional microbial agents to target and regulate saline-alkali ions, a drip irrigation fertigation system to dynamically maintain rhizosphere microecological activity, and a tiered management system for leguminous-cruciferous green manure, coupled with physical salt suppression and bio-fertilization, to form a closed loop of "improvement-production-efficiency enhancement." Its core effects are manifested in:

[0034] 1. Improved soil health: Soil sodium adsorption ratio (SAR) decreased by more than 52% in the current season, and the annual increase in organic matter reached 0.6 g / kg, breaking through the bottleneck of lagging improvement of saline-alkali land.

[0035] 2. Excellent yield and quality: Spring wheat yield increased by 19% to 482 kg / mu.

[0036] This invention achieves the goal of "improving saline-alkali land and achieving high yields in the same year" by integrating three core technologies: modular microbial agent design, dynamic regulation of drip irrigation, fertilization, and microbial integration, and spatiotemporal hierarchical management of green manure. It solves problems such as low microbial survival rates, insufficient soil improvement efficiency of green manure, and low yields of crops in saline-alkali land that exist in existing technologies. Attached Figure Description

[0037] For illustrative and not limiting purposes, the invention will now be described with reference to preferred embodiments thereof, particularly the accompanying drawings, in which:

[0038] Figure 1 The results show the comparison of the effects of saline-alkali soil improvement and yield increase in Example 1 and the comparative example.

[0039] Figure 2 This is a comparison of soil pH and wheat yield under different treatments in Example 2.

[0040] Figure 3 This is a comparison of soil carbon and nitrogen enzyme activity under different treatments in Example 2.

[0041] Figure 4 The results show the comparison of soil residual carbon content under different treatments in Example 2.

[0042] Figure 5 The results of soil salinity comparison between the staged green manure return treatment and the control group. Detailed Implementation

[0043] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0044] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0045] I. Pre-planting preparations (early March)

[0046] 1. Land preparation: Deep plowing with a combined tillage machine to 20 cm, breaking up the compacted layer, harrowing and compacting; opening micro-ridges and furrows: ridge height 12±2 cm, ridge width 45±5 cm, furrow depth 15 cm.

[0047] 2. Preparation of base fertilizer:

[0048] Microbial inoculants: Bacillus subtilis ACCC 11025, Bacillus amyloliquefaciens ACCC 19743, and Bacillus mucilaginosus ACCC 10013 were all purchased from the Agricultural Culture Collection of China (ACCC). Each strain was cultured for 3 days at 30℃ and 150 rpm in TSB liquid medium with shaking. Cells were then collected at room temperature (8,000 r / min, 5 min) and resuspended in TSB liquid medium to OD. 600 The concentration was 0.4-0.6, and finally mixed at a volume ratio of 1:1:1 to prepare a microbial inoculum for later use. The TSB liquid culture medium was prepared with tryptone (17.0 g / L), soybean peptone (3.5 g / L), sodium chloride (5.0 g / L), dipotassium hydrogen phosphate (2.5 g / L) and glucose (2.5 g / L), with a pH of 7.3±0.2.

[0049] Reduced fertilizer dosage: Urea dosage reduced by 30% (by weight) (from 14 kg / mu to 9.8 kg / mu under conventional application), superphosphate dosage reduced by 9 kg / mu.

[0050] Mixing method: Mix 3 kg / mu of microbial inoculant with chemical fertilizer (9.8 kg / mu of urea and 9 kg / mu of superphosphate) at a mass ratio of 3:18.8 ≈ 1:6.3, avoiding direct sunlight. Contraindications: Avoid applying alone in fields with pH > 8.5 or salt content > 0.6%; it must be activated in conjunction with a drip irrigation system.

[0051] II. Spring Wheat Planting Management (Mid-March to Mid-July)

[0052] Table 1 Spring Wheat Planting Management

[0053]

[0054] 1. Optimization of the configuration of the drip irrigation water, fertilizer and bacteria integrated system

[0055] Drip tape burial depth: 10±1 cm (salt active layer);

[0056] Drip spacing: 30 cm (pressure compensated type, flow rate 2.2 L / h);

[0057] Activator formulation: Trehalose 35 g / L, humic acid 25 g / L, potassium dihydrogen phosphate 5 g / L (pH 6.5-7.0).

[0058] III. Replanting with green manure after wheat harvest (late July to late October)

[0059] 1. Mixed seeding operation:

[0060] Seed treatment: Hairy vetch (variety: Turkmen hairy vetch, purchased from the Grassland Research Institute of Chinese Academy of Agricultural Sciences) and forage rape (variety: Huayouza 62, purchased from the National Rapeseed Engineering Technology Research Center of Huazhong Agricultural University) were mixed at a planting density ratio of 3:1 by weight.

[0061] Sowing rate: 4 kg / mu of hairy vetch + 0.2 kg / mu of forage rapeseed.

[0062] Sowing method: Shallow furrow sowing using a row seeder.

[0063] Sowing depth: 2-3 cm (too deep will inhibit rapeseed emergence).

[0064] Row spacing configuration: 25 cm equal row spacing (vetch and rapeseed are intercropped in separate rows).

[0065] 2. Tiered Management:

[0066] Table 2 Tiered Management

[0067]

[0068] IV. Soil conservation during the overwintering period (November to February of the following year)

[0069] Cover layer decomposition: Hairy vetch stalks decompose slowly at low temperatures of -15~5℃, releasing organic acids (pH 6.2-6.8) to neutralize salt and alkali.

[0070] Low-temperature decomposition optimization: If the winter temperature is below -20℃, additional decomposition microbial agents should be applied. The decomposition microbial agent consists of the following bacteria: Bacillus subtilis ACCC 11025 (40-55% by mass), Lactic acid bacteria ATCC 8014 (25-35% by mass), Flavobacterium ATCC 17061 (7-13% by mass), Rhizopus oryzae ATCC 20344 (1-5% by mass), and Aspergillus niger ATCC 16404 (3-8% by mass). Bacillus subtilis was purchased from the Agricultural Culture Collection of China (ACCC), while Lactic acid bacteria, Flavobacterium oryzae, Rhizopus oryzae, and Aspergillus niger were purchased from the American Type Culture Collection. The decomposition microbial agent accelerates the decomposition of the covering layer; the application rate is 2-5 kg / acre.

[0071] V. Annual cycle begins (March of the following year)

[0072] 1. Tillage and integration: The combined tillage machine is used to deeply till the soil to 25±2 cm, mixing the green manure stubble and mulch into the tillage layer; after tillage, the soil is leveled by rotary harrowing, and the soil bulk density is reduced to 1.25 g / cm³ (initially 1.40 g / cm³).

[0073] 2. New season sowing: Reapply microbial inoculants (reduced to 2.5 kg / mu) to start a new cycle.

[0074] Example 1: A planting method that simultaneously improves soil health and crop yield in saline-alkali land

[0075] According to the above technical plan, the experiment was conducted in Linhe District, Bayannur City, Inner Mongolia (40°76′N, 107°42′E), which is a typical mildly to moderately saline-alkali land in the Hetao Irrigation District (soil salinity 0.35% ± 0.05, pH 8.2 ± 0.3). The experiment period was from March 2024 to July 2025. The specific experimental steps were as follows: pre-sowing treatment was carried out on March 10, with deep plowing to 20 cm and creating small ridges (ridge height 12 cm, ridge width 45 cm). Basal application of 30% nitrogen-reduced fertilizer (9.8 kg / mu of urea + 9 kg / mu of superphosphate) mixed with 3 kg / mu of compound microbial inoculant was applied. Spring wheat was planted from March 15 to July 20, using the variety Yongliang No. 4, with a sowing rate of 25 kg / mu. The planting method employs shallow-buried drip irrigation and furrow sowing technology, with planting ridges 10-15cm high, drip irrigation tape buried 8-12cm deep, and dripper spacing 30cm. During the jointing and grain-filling stages of spring wheat, 0.5g / L of the prepared microbial activator (each L contains 30g trehalose, 20g humic acid, and 5g potassium dihydrogen phosphate) is delivered twice via the drip irrigation system. After wheat maturity, the straw is crushed to ≤5cm and returned to the field, followed by replanting with 4 kg / mu of hairy vetch and 0.2 kg / mu of forage rape (mixed planting, row spacing 25cm). The above-ground parts of the rape are harvested in early October (yielding 2.85 tons / mu of silage). During the frost period (November 5th), the crushed vetch is used to cover the surface (5cm thick). This cycle is repeated annually (on March 8th of the following year): a combined tillage machine is used for deep plowing to 25cm, integrating stubble and mulch.

[0076] Experimental results:

[0077] (1) Spring wheat yield: The wheat was manually harvested by placing a 1 m × 1 m harvesting frame in the center of each plot, threshing and drying the wheat, and then weighing it to calculate the yield; the result was 486 kg / mu.

[0078] (2) Soil sodium adsorption ratio (SAR) in the current season: Soil Na was determined by iCAPPROX inductively coupled plasma atomic emission spectrometer (2110). + Ca 2+ and Mg 2+ Concentration; Measured result: 7.20 mmol / L.

[0079] (3) Organic matter content: The organic matter content was determined by potassium dichromate titration method-external heating method; the result was 1.53%.

[0080] (4) Total nitrogen content: The total nitrogen content was determined by the Kjeldahl method; the result was 0.84 g / kg.

[0081] Comparative Example 1 (No bacterial agent applied)

[0082] No compound microbial inoculants were used; instead, full-grain fertilizer (14 kg / mu of urea) was applied. During the jointing and grain-filling stages of spring wheat, clean water was delivered twice via drip irrigation (without adding a microbial activator containing 30 g / L trehalose and 20 g / L humic acid). The planting of wheat and its subsequent green manure followed the same procedures as in Example 1.

[0083] Experimental results:

[0084] (1) Spring wheat yield: The method of measurement is the same as in Example 1; the result is 418 kg / mu.

[0085] (2) SAR: The measurement method is the same as in Example 1; the measurement result is 9.11 mmol / L.

[0086] (3) Organic matter content: The determination method is the same as in Example 1; the result is 1.05%.

[0087] (4) Total nitrogen content: The determination method is the same as in Example 1; the result is 0.68 g / kg.

[0088] Comparative Example 2 (Activation without drip irrigation)

[0089] Apply 3.5 kg / mu of compound microbial inoculant, combined with a 30% reduction in chemical fertilizer (9.8 kg / mu of urea). During the jointing and grain-filling stages of spring wheat, deliver clean water twice via drip irrigation (without adding the microbial activator containing 30 g / L trehalose + 20 g / L humic acid). The planting of wheat and its post-harvest green manure remains consistent with Example 1.

[0090] Experimental results:

[0091] (1) Spring wheat yield: The method of measurement is the same as in Example 1; the result is 435 kg / mu.

[0092] (2) SAR: The measurement method is the same as in Example 1; the measurement result is 13.8 mmol / L.

[0093] (3) Organic matter content: The determination method is the same as in Example 1; the result is 1.22%.

[0094] (4) Total nitrogen content: The determination method is the same as in Example 1; the result is 0.71 g / kg.

[0095] Comparative Example 3 (Green Manure Monoseeding)

[0096] Apply 3.5 kg / mu of compound microbial inoculant, combined with a 30% reduction in chemical fertilizer (9.8 kg / mu of urea). During the jointing and grain-filling stages of spring wheat, administer 0.5 g / L of microbial activator (containing 30 g / L of trehalose and 20 g / L of humic acid) twice via drip irrigation. Wheat planting and harvesting are consistent with Example 1, but after wheat, vetch (6 kg / mu) is sown monoculture, without forage rapeseed intercropping and staged harvesting.

[0097] Experimental results:

[0098] (1) Spring wheat yield: The method of measurement is the same as in Example 1; the result is 452 kg / mu.

[0099] (2) SAR: The measurement method is the same as in Example 1; the measurement result is 10.5 mmol / L.

[0100] (3) Organic matter content: The determination method is the same as in Example 1; the result is 1.38%.

[0101] (4) Total nitrogen content: The determination method is the same as in Example 1; the result is 0.70 g / kg.

[0102] Control group (conventional planting)

[0103] Base application of complete chemical fertilizer (14 kg / mu of urea + 9 kg / mu of superphosphate); no microbial inoculants; during the jointing and grain-filling stages of spring wheat, clean water is delivered twice via drip irrigation (without adding microbial activators containing 30 g / L of trehalose + 20 g / L of humic acid). The land is left fallow after wheat harvest (no green manure planting).

[0104] Experimental results:

[0105] (1) Spring wheat yield: The method of measurement is the same as in Example 1; the result is 402 kg / mu.

[0106] (2) SAR: The measurement method is the same as in Example 1; the measurement result is 15.6 mmol / L.

[0107] (3) Organic matter content: The determination method is the same as in Example 1; the result is 0.88%.

[0108] (4) Total nitrogen content: The determination method is the same as in Example 1; the result is 0.63 g / kg.

[0109] The experimental results of Example 1 above were compared with those of Comparative Examples 1, 2, and 3, as well as the control group. The results are as follows: Figure 1 As shown. By Figure 1As can be seen, the embodiments can significantly increase wheat yield by 7.52-20.90%, significantly reduce sodium adsorption ratio by 13.33-41.67%, significantly increase organic matter content by 10.87-73.86%, and significantly increase total nitrogen content by 19.5-33.1%, thus having the effect of improving soil fertility and increasing yield.

[0110] Example 2: Comparison of Field Effects of Different Combined Inoculants

[0111] The field experiment was conducted in Linhe District, Bayannur City, Inner Mongolia (40°76′N, 107°42′E), which is a typical mild to moderate saline-alkali land in the Hetao Irrigation Area (soil salinity 0.35% ± 0.05, pH 8.2 ± 0.3). The experiment was conducted from March 2024 to July 2025. Four types of microbial agents were set up for treatment: (1) Treatment 1: Bacillus subtilis ACCC 11025, Bacillus amyloliquefaciens ACCC 19743, and Bacillus spp. ACCC 10013 compound microbial agent implemented in this invention; (2) Treatment 2: Commercially available compound microbial agent (microbial agent (Heilongjiang Shengxuzhunzi

[2022] No. 132), purchased from Heilongjiang Heiwotu Biotechnology Co., Ltd.); (3) Treatment 3: Control (CK): No microbial agent was applied. The area of ​​each treatment was 40 m². 2 (5m × 8m), randomized block design, repeated 3 times. In Example 2 of this invention, treatments 1, 2 and 3, based on different inoculant applications, maintained the same nitrogen fertilizer application, planting methods and sampling and measurement methods as in Example 1.

[0112] Experimental results:

[0113] The effects of different treatments on soil pH and spring wheat yield in saline-alkali land were analyzed.

[0114] (1) Soil pH: Soil pH was measured using a pH meter (FE20) (soil-to-water ratio 5:1); the results are as follows. Figure 2 As shown: Process 1 (8.76), Process 2 (8.86) and Process 3 (8.92).

[0115] (2) Spring wheat yield: 1m×1m harvesting frames were placed in the center of each plot for manual harvesting. After threshing and drying, the wheat was weighed and the yield was calculated. The results are as follows: Figure 2 As shown; Treatment 1 (560 kg / mu), Treatment 2 (524 kg / mu) and Treatment 3 (501 kg / mu).

[0116] (3) Soil enzyme activity: Soil carbon and nitrogen enzyme activities were determined using a 96-well plate fluorescence assay. β-glucosidase: Treatment 1 (241.4 nmol / g / h), Treatment 2 (201.3 nmol / g / h), and Treatment 3 (167.8 nmol / g / h). Xylanase: Treatment 1 (22.5 nmol / g / h), Treatment 2 (19.5 nmol / g / h), and Treatment 3 (14.9 nmol / g / h). Cellobiosidase: Treatment 1 (23.3 nmol / g / h), Treatment 2 (17.5 nmol / g / h), and Treatment 3 (14.2 nmol / g / h). Leucine aminopeptidase: Treatment 1 (504.6 nmol / g / h), Treatment 2 (368.6 nmol / g / h), and Treatment 3 (275.4 nmol / g / h). Chitinase: Treatment 1 (31.7 nmol / g / h), Treatment 2 (25.9 nmol / g / h), and Treatment 3 (22.5 nmol / g / h). Alkaline phosphatase: Treatment 1 (282.2 nmol / g / h), Treatment 2 (255.7 nmol / g / h), and Treatment 3 (229.4 nmol / g / h), results are as follows. Figure 3 As shown.

[0117] (4) Residual carbon: Soil residual carbon content was determined using the aminoglycoside biomarker method; Bacterial residual carbon: Treatment 1 (506.1 mg / kg), Treatment 2 (459.3 mg / kg), and Treatment 3 (226.0 mg / kg). Fungal residual carbon: Treatment 1 (2420.0 mg / kg), Treatment 2 (2132.8 mg / kg), and Treatment 3 (1895.7 mg / kg). Microbial residual carbon: Treatment 1 (2965.6 mg / kg), Treatment 2 (2766.7 mg / kg), and Treatment 3 (2604.7 mg / kg). Plant residual carbon: Treatment 1 (189.2 mg / kg), Treatment 2 (161.1 mg / kg), and Treatment 3 (175.4 mg / kg). The results are as follows: Figure 4 As shown.

[0118] according to Figure 2 , Figure 3 and Figure 4The results show that the combined use of the microbial agents of this invention (treatment 1) significantly reduced soil pH by 0.10-0.16 units, significantly increased wheat yield by 2.8%-6.7%, significantly increased soil carbon, nitrogen, and phosphorus enzyme activity by 15.3-82.9%, and increased microbial residue by 7.2-123.9% and plant residue by 7.8-17.4%. This demonstrates the effectiveness of improving soil salinity, enhancing soil carbon, nitrogen, and phosphorus enzyme activity, and increasing soil residual carbon and crop yield. This indicates that the soil's "biological engine" has been successfully activated. The vigorous enzyme activity drives the rapid transformation of organic matter and the efficient cycling of nutrients, accelerating the decomposition of organic waste such as straw into available nutrients, providing a continuous nutrient supply for the current crop growth, and significantly improving fertilizer utilization. More importantly, by significantly increasing microbial and plant residue carbon, a solid material foundation for soil health is laid. These microbial residues are the core cementing substances that form stable soil aggregates, and together with plant residues, they constitute a durable and core component of soil organic matter. Their synergistic increase greatly promotes the formation of soil aggregates, not only coordinating the water-air imbalance in the soil and enhancing its moisture retention capacity, but also effectively inhibiting the accumulation of salts on the surface as water evaporates, thus physically blocking the harmful effects of salinity. In summary, this invention, through three pathways—lowering pH to improve the soil chemical environment, stimulating enzyme activity to enhance soil biological functions, and accumulating residual carbon to build a healthy soil physical structure—constitutes a virtuous cycle of "chemical-biological-physical" improvement. This cycle ultimately effectively overcomes the obstacles of saline-alkali land, simultaneously achieving rapid restoration of soil vitality and steady improvement in crop yield and quality, providing reliable technical support for the sustainable utilization of saline-alkali land.

[0119] Core innovations:

[0120] 1. Modular microbial inoculants:

[0121] The compound microbial agents utilize the principle of complementary functions. Bacillus subtilis specifically adsorbs Na⁺, reducing the SAR value by 35%; Bacillus subtilis promotes the formation of soil aggregates, increasing water holding capacity by 20%; and Bacillus amyloliquefaciens can regulate soil phosphatase and urease activity, increasing soluble phosphorus content.

[0122] 2. Integrated Water, Fertilizer, and Microbial Drip Irrigation: The drip irrigation tape is buried deep into the salt-active layer (8-12cm), directly delivering water to the crop root zone, reducing evaporation and deep seepage losses, and significantly saving water. Furthermore, soluble fertilizers dissolve directly in the water and are precisely and evenly applied to the crop roots along with the irrigation water, reducing fertilizer loss, improving fertilizer utilization, and lowering fertilizer input costs. Simultaneously, the addition of microbial agents plays a positive role in improving the soil ecological environment and promoting soil health.

[0123] 3. Staged Green Manure Salt Suppression and Fertilization: Compared with direct full return of green manure to the field (control), harvesting forage rape during the full flowering period combined with crushing hairy-leaf vetch after frost significantly reduced soil salinity: harvesting forage rape during the full flowering period reduced soil salinity by 12.9%, while crushing hairy-leaf vetch after frost reduced soil salinity by 25.2%. (See results below.) Figure 5 As shown.

[0124] Table 3. Comparison of soil salinity between the staged green manure return treatment and the control.

[0125]

[0126] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A planting method that simultaneously improves soil health and crop yield in saline-alkali land, comprising the following steps: (1) Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus spp. were respectively adjusted to OD using liquid culture medium. 600 The concentration is 0.4-0.6, and the mixture is prepared into a compound microbial agent; the compound microbial agent is then mixed with chemical fertilizer to prepare a base fertilizer; (2) During the crop sowing period, the base fertilizer is applied to the side and below the crop seeds; during the crop jointing and grain-filling stages, a microbial activator is delivered using a drip irrigation system; the microbial activator is prepared from the following components at the following concentrations: trehalose 30-40 g / L, humic acid 20-30 g / L and potassium dihydrogen phosphate 4-6 g / L, pH 6.5-7.0; within 24 hours after irrigation during the crop jointing stage, the microbial activator is delivered using a drip irrigation system at a concentration of 0.5 g / L-1.0 g / L for 1-2 hours; on the day of irrigation during the crop grain-filling stage, the microbial activator is delivered using a drip irrigation system at a concentration of 0.5 g / L-1.0 g / L for 1-2 hours. (3) After the crop matures, the crop straw is crushed to ≤5cm and returned to the field, and legumes and cruciferous crops are replanted; the above-ground parts of the cruciferous crops are harvested for silage; the legumes are crushed and covered with soil during the frost period; this cycle is repeated year by year. In step (1), the bacterial suspensions of Bacillus subtilis, Bacillus amyloliquefaciens, and Bacillus spp. are mixed in a volume ratio of (0.9-1.1):(0.9-1.1):(0.9-1.1). The fertilizer used in step (1) is a nitrogen-reducing fertilizer; the nitrogen-reducing fertilizer includes urea and superphosphate; the mass ratio of the compound microbial agent to the nitrogen-reducing fertilizer is 1:5 to 1:6.3; Improving the health of saline-alkali soil means improving one or more of the following indicators: reducing the soil sodium adsorption ratio, increasing organic matter content, increasing total nitrogen content, reducing soil pH, increasing soil carbon, nitrogen, phosphorus enzyme activity, or increasing soil residual carbon content. The increase in soil carbon, nitrogen, phosphorus enzyme activity is achieved by increasing the activity of one or more of the following enzymes: β-glucosidase, xylanase, cellobiase, leucine aminopeptidase, chitinase, or alkaline phosphatase. The increase in soil residual carbon content refers to increasing the carbon content of one or more of the following: bacterial residual carbon, fungal residual carbon, microbial residual carbon, or plant residual carbon.

2. The planting method for simultaneously improving soil health and crop yield in saline-alkali land according to claim 1, characterized in that: The nitrogen-reducing fertilizer is a fertilizer with a nitrogen reduction of 20-30%; the urea (8-10 kg / mu), the superphosphate (8-10 kg / mu), and the compound microbial agent (3-4 kg / mu) are mixed and applied.

3. The planting method for simultaneously improving soil health and crop yield in saline-alkali land according to claim 1, characterized in that: In step (3), the legume crop is hairy vetch; the cruciferous crop is rapeseed; the planting density ratio of hairy vetch and rapeseed is 2.5:1-3.5:1; the sowing amount of hairy vetch is 3-4 kg / mu; the sowing amount of rapeseed is 0.2-0.5 kg / mu.

4. The planting method for simultaneously improving soil health and crop yield in saline-alkali land according to any one of claims 1-3, characterized in that: The crop is wheat; the wheat is the spring wheat variety Yongliang No. 4.

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