A soda saline and alkaline grassland vegetation restoration method based on precise water and salt regulation

Abstract

The application discloses a soda saline-alkali grassland vegetation restoration method based on precise water and salt regulation, which comprises the following steps: collecting surface soil in a native vegetation area, performing acid activation pretreatment on the collected surface soil by using a dilute hydrochloric acid solution to obtain an activated seed bank matrix; mixing the activated seed bank matrix with desulfurized gypsum, zeolite powder and mature organic fertilizer to prepare a composite transplanting matrix, and arranging a seed source island; arranging a pressure compensation type drip irrigation belt under the seed source island and providing a silicone functional liquid injection device, constructing a real-time monitoring network through a water content sensor and a salt content sensor, and performing three-stage irrigation regulation, i.e., a leaching stage, a self-adaptive regulation stage and a deficiency induction stage; periodically measuring vegetation coverage in a growing season, and performing coverage feedback control by using a closed-loop ratio integral control algorithm. The soda saline-alkali grassland vegetation is rapidly restored by integrating seed bank acid activation, silicone functional liquid-drip irrigation coupling water and salt regulation and a vegetation coverage feedback control system.

Description

Technical Field

[0001] This invention relates to the field of saline-alkali land ecological restoration and grassland agriculture technology, specifically to a method for vegetation restoration of soda saline-alkali grassland based on precise water and salt regulation, and more specifically to a method for rapid vegetation restoration of soda saline-alkali grassland that integrates directional transplantation of soil seed bank, organosilicon functional liquid-drip irrigation, precise water and salt regulation, and dynamic feedback control of vegetation cover. Background Technology

[0002] Songnen Grassland is a concentrated distribution area of ​​soda saline-alkali land, characterized by high alkalinity, high salinity, and high compaction, with a pH value generally above 9.5, and even exceeding 10.5 in some areas. Salt-tolerant plants form a unique vegetation landscape on soda saline-alkali grasslands, which is of great significance for protecting the ecological environment and black soil regions. With the impact of climate change and human activities, grassland vegetation is increasingly degraded, and how to efficiently and accurately restore vegetation communities has become an urgent problem to be solved.

[0003] In the field of vegetation restoration of soda saline-alkali grasslands, existing technologies mainly have the following prominent problems:

[0004] First, the seed bank has a low utilization rate and is difficult to germinate. The natural soil seed bank on soda saline-alkali grassland contains abundant salt-tolerant germplasm resources, but the germination rate is extremely low under high salt and alkali stress, and the reproductive potential of the seed bank itself has not been fully activated.

[0005] Second, water and salt regulation is crude, and the contradiction between salt return and water consumption is prominent. Although flood irrigation can leach salt, it consumes a lot of water and easily causes salt to accumulate on the surface; although ordinary drip irrigation saves water, it has low infiltration and diffusion efficiency in compacted soil.

[0006] Third, most existing irrigation technologies ignore the feedback regulation effect of vegetation cover on surface evaporation and salt transport. High cover leads to strong surface evaporation and increased salt transport, while low cover leads to faster salt return, forming a vicious cycle of "salt damage - sparse vegetation - increased salt return - further sparse vegetation".

[0007] Therefore, there is an urgent need in this field for a method that can systematically solve the above problems and achieve rapid vegetation restoration in soda saline-alkali grasslands. Summary of the Invention

[0008] In view of this, the present invention integrates the acidic activation pretreatment of soil seed bank, the precise regulation of water and salt in three stages coupled with organosilicon functional liquid and drip irrigation, and the dynamic integral feedback control of vegetation cover into a closed-loop control system of "seed source-water-salt-coverage", so as to achieve the rapid restoration goal of "sowing in the same year, establishing turf in the same year, stabilizing in two years, and self-maintaining in three years".

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] This invention provides a method for vegetation restoration in soda saline-alkali grassland based on precise water and salt regulation, comprising the following steps:

[0011] Step 1: Targeted collection and acid activation pretreatment of soil seed bank

[0012] Topsoil from native vegetation areas of soda saline-alkali grassland was collected as a germplasm resource bank. The soil was sprayed with a dilute hydrochloric acid solution with a pH of 1.8 to 2.2 to moisten the soil to 55% to 65% of the field water holding capacity, and then sealed for 60 to 72 hours to obtain an acid-activated seed bank substrate.

[0013] Seeds in the seed bank of soda saline-alkali grasslands are in a dormant and inhibited state due to high pH and high salinity. The seed surface is often covered with a dense waxy or mineralized layer, making it difficult to break dormancy effectively with conventional germination methods. Acidic activation pretreatment lowers the local pH, synergistically disrupts the seed coat barrier, and activates the seed's endogenous hormone system, restoring the seed's responsiveness to water and oxygen. This lays the biological foundation for subsequent germination promotion with organosilicon functional liquid.

[0014] In this invention, the acidic activation pretreatment lowers the local pH, synergistically disrupts the seed coat barrier, activates the seed's endogenous hormone system, and restores the seed's responsiveness to water and oxygen. During this process, the low pH environment synergistically achieves three key functions: (1) killing some salt-intolerant weed seeds through an acidic environment, reducing competition from unwanted species; (2) performing physicochemical layer treatment on salt-tolerant plant seeds, breaking seed dormancy; and (3) the acidic conditions partially dissolve and expel salt from the seed bank, reducing initial salt stress during seed germination. For the specific needs of hard-seedled plants such as Leymus chinensis, further enhanced treatment with dilute sulfuric acid (pH=1.5~2.0) can be used to improve seed coat permeability.

[0015] Step 2: Preparation of composite transplanting substrate and establishment of seed islands

[0016] The acidic activated seed bank substrate is mixed with desulfurized gypsum, zeolite powder and decomposed organic fertilizer in a mass ratio of (60~65):(12~15):(12~15):(8~10) to form a composite transplanting substrate. Seed islands are arranged in the remediation area at a density of 1.5~2 seed islands per square meter.

[0017] In this composite matrix, desulfurized gypsum provides calcium ions to replace exchangeable sodium ions on the soil colloid surface, reducing the sodium adsorption ratio (SAR). Zeolite powder utilizes its unique porous structure to adsorb sodium ions, increasing the soil cation exchange capacity and improving soil permeability. Well-rotted organic fertilizer provides organic nutrients and beneficial microorganisms for seed germination and early seedling growth. The combined use of desulfurized gypsum and zeolite powder complements each other in reducing soil pH and promoting ion exchange—desulfurized gypsum focuses on calcium-sodium replacement, while zeolite powder focuses on ion adsorption and slow-release salt control. This composite matrix has an organic matter content ≥10% and a total porosity ≥55%, providing an ideal microenvironment for seed germination and early seedling root development.

[0018] Step 3: Deployment of the organosilicon functional liquid-drip irrigation coupling system and intelligent water and salt regulation

[0019] Pressure-compensated drip irrigation tape is installed 10-15 cm below the seed source island, equipped with an organosilicon functional liquid injection device. Simultaneously, a main control moisture sensor and a salinity sensor are installed at a soil depth of 15 cm, and auxiliary moisture sensors and auxiliary salinity sensors are installed at 5 cm and 25 cm, respectively, to construct a real-time monitoring network. Data from the 15 cm depth sensor is used as the primary control basis, with data from 5 cm and 25 cm depths serving as auxiliary references. When the EC value at 5 cm depth is higher than the EC value at 15 cm depth and the difference is >1.5 dS / m, the controller automatically increases the drip irrigation frequency to suppress surface salt return. When the EC value at 25 cm depth is consistently lower than the EC value at 15 cm depth, it indicates insufficient leaching, and the controller automatically increases the single irrigation volume by 20%. When data from the three depth sensors conflict, the irrigation decision is executed based on the 15 cm depth data, and the system records anomalies.

[0020] Three-stage irrigation regulation is implemented based on soil sensor data:

[0021] Drenching stage: From day 0 to 20 after transplanting, maintain the rhizosphere water potential at -5 to -10 kPa. Add organosilicon functional solution to the drip irrigation water at a rate of 0.8 to 1.2 L / acre per application, with a single irrigation volume of 15 to 25 m³. 3 / mu, when EC at a depth of 15 cm > 4.0 dS / m, the system automatically adds acid to adjust the pH of the irrigation water to 6.5~7.0; the conditions for switching to the adaptive control stage are: the time after transplanting ≥ 20 days, and the EC value at a depth of 15 cm ≤ 4.0 dS / m for 3 consecutive days, and the water potential at a depth of 15 cm stable within the range of -5~-10 kPa for 3 consecutive days; if the EC does not meet the standard on the 20th day, the rinsing stage is extended by 3 days each time, and the single irrigation volume is increased by 20% until the EC meets the standard and then the system switches; if the standard is still not met by the 30th day, the system alarm is triggered.

[0022] Adaptive regulation phase: From day 21 to 120 post-transplantation, maintain the rhizosphere water potential at a depth of 15 cm at -10 to -15 kPa, with a target EC range of 1.5 to 2.5 dS / m. Reduce the dosage of organosilicon functional solution to 0.4 to 0.6 L / acre per application, and the single irrigation volume to 10 to 15 m³. 3 / acre; The conditions for switching to the deficit induction stage are: ≥120 days after transplanting, and vegetation cover ≥55% in two consecutive monitoring sessions (10-15 days apart), and EC value at 15 cm depth ≤2.5 dS / m for 7 consecutive days; If the cover does not meet the standard on the 120th day, the adaptive control stage is extended by 15 days each time, maintaining the current irrigation parameters until the cover meets the standard and then switching is initiated; If the standard is still not met by the 150th day, the reseeding procedure is triggered;

[0023] Deficiency induction phase: After 121 days post-transplantation, maintain a rhizosphere water potential of -15 to -20 kPa at a depth of 15 cm, strictly control EC below 3.0 dS / m, reduce the dosage of organosilicon functional solution to 0.2-0.3 L / acre per application, and use 8-10 m³ of water per application. 3 / mu, extend the drying time to 2-3 days;

[0024] The silicone functional liquid is added through the injection line at the end of the drip irrigation system, with the injection point located after the filter and before the valve, and the injection pressure is 0.10~0.15 MPa. The drip irrigation system starts an automatic backwashing program every 48 hours of operation, lasting for 3~5 minutes, with a flushing pressure of 0.15~0.20 MPa, and the pipeline is flushed with clean water for 2~3 minutes after each injection. The silicone functional liquid is pre-filtered using a multi-stage filtration system, which includes 120-mesh and 200-mesh disc filters, and a 150-mesh online screen filter is installed at the injection port of the drip irrigation system.

[0025] The organosilicon functional liquid is a nonionic organosilicon surfactant selected from one or more of the following materials: MQ911 agricultural synergist, Silwet L-77, Silway 240, organosilicon polyoxyethylene ether surfactant, and water-soluble fertilizer containing organosilicon humic acid. When added to drip irrigation water, it reduces the surface tension of the irrigation water to 45-50 mN / m. Its hydrophilic and hydrophobic groups in its molecular structure can be oriented at the gas-liquid interface, reducing the surface tension of the aqueous solution from 72 mN / m in pure water to 45-50 mN / m, a reduction of more than 30%. This concentration of organosilicon solution reduces the wetting angle of soda-alkali soil particles from 85°-95° ​​to 35°-45°, increasing the lateral diffusion diameter of irrigation water in compacted soil to 60-80 cm (compared to only 30-40 cm for pure water under the same conditions), increasing the water infiltration rate by 50%-100%, and improving leaching efficiency by more than 40%.

[0026] Based on this, the organosilicon functional liquid and the drip irrigation system form a synergistic effect: the organosilicon functional liquid reduces the surface tension of irrigation water, enhancing the infiltration and diffusion capacity of water in compacted soil; the drip irrigation system precisely delivers the organosilicon-containing irrigation water to the root zone, achieving targeted regulation and forming a three-in-one water-salt coupling regulation mechanism of "active infiltration promotion + rhizosphere protection + targeted delivery". After applying the organosilicon functional liquid, the siloxane skeleton in the organosilicon molecule adsorbs onto the hydrophilic groups on the surface of soil particles, forming a nanoscale hydrophobic film. Simultaneously, its hydrophilic side chains form a hydrogen bond network with water molecules, establishing a "diluted saline protective zone" microenvironment with an "ion repulsion effect" in the rhizosphere soil. + Isosal ions are excluded from the protective zone and migrate downwards with the irrigation water to the root zone. The salt concentration in the protective zone can be 30% to 50% lower than that in the surrounding soil, providing a safe "refuge" for seed germination and early seedling growth under low salt stress.

[0027] The coupling of organosilicon functional liquid and drip irrigation system is not a simple superposition, but rather forms a complementary synergistic relationship: the organosilicon functional liquid solves the structural barrier of "water not penetrating" in soda-alkali soils—by reducing surface tension, it allows water to actively diffuse and infiltrate in compacted soils; while the drip irrigation system precisely targets and delivers the organosilicon functional liquid to the root zone of the seed island, avoiding the problems of surface application being washed away by rainwater or lost through evaporation. In the spatial dimension, the two achieve a connection between "precise delivery" and "active infiltration promotion," and in the temporal dimension, they achieve a fusion of "on-demand supply" and "long-term protection." This synergy reduces the amount of organosilicon functional liquid used by 60%–70% compared to surface application, and reduces irrigation water consumption by 50%–60% compared to flood irrigation, resulting in significant cost-effectiveness.

[0028] Step 4: Dynamic integral feedback control of vegetation cover

[0029] During the growing season, vegetation cover is measured regularly, and a closed-loop ratio integral control algorithm is used for cover feedback control: the target cover is set to a lower limit of 55% and an upper limit of 75%. When the cover is <40%, the reseeding program is started and the drip irrigation frequency is increased. When the cover is 40%~60%, the adaptive control stage parameters are maintained and light mowing is carried out. When the cover is >80%, the dry and wet alternation suppression program is started.

[0030] The vegetation cover is measured periodically every 10-15 days using UAV multispectral imagery or ground photography; the reseeding procedure is as follows: composite transplanting substrate at 80-120 g / m². 2 Broadcasting and drip irrigation frequency increased to 1-2 times daily to maintain water potential at -5 to -8 kPa; light mowing is performed once a month, leaving a stubble of 8-10 cm, and the drip irrigation volume is increased by 10%-15% within 24 hours after mowing;

[0031] The dry-wet alternation suppression procedure is as follows: stop irrigation for 5 to 7 days until the soil water potential is below -40 kPa, then resume irrigation until the water potential is -12 to -15 kPa, and repeat the dry-wet alternation cycle every two weeks thereafter until the soil cover falls back to below 75%.

[0032] The advantage of this integral control algorithm lies in avoiding the frequent oscillations that may be caused by simple threshold control, making the regulation behavior smoother and more stable. In traditional saline-alkali land restoration, vegetation cover is only used as an evaluation indicator, and its regulatory role is completely ignored. This invention is the first to incorporate vegetation cover into a closed-loop control system. Through a two-way regulation strategy of "alternating between dry and wet conditions to promote root development when the cover is high and reseeding to promote propagation when the cover is low," the dynamic balance of the grassland ecosystem is achieved. This breaks the two vicious cycles of "excessive cover → root layer salt accumulation → increased evaporation → ecological degradation" and "excessive cover → evaporation and salt return → sparse vegetation," realizing a qualitative change in the grassland ecosystem from passive restoration to active regulation.

[0033] As a preferred embodiment of the present invention, after completing the above four steps, further subsequent management can be implemented: starting from the second year, only local bare patches (coverage <40%) are reseeded, and the remaining areas are maintained autonomously by drip irrigation and coverage feedback. Organosilicon functional liquid is only applied as needed during the spring greening period and the summer drought period.

[0034] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a solution with the following beneficial effects:

[0035] (1) Fast germination. Acidic activation pretreatment advances the germination time of seed bank by more than 30% and increases the coverage by more than 2 times after 60 days, effectively solving the problem of low germination rate of seed bank.

[0036] (2) Water saving and salt reduction. The coupling of organosilicon functional liquid with drip irrigation increases the lateral diffusion diameter of irrigation water by more than 1 times, increases the infiltration rate by 50%~100%, increases the leaching efficiency by more than 40%, reduces the amount of organosilicon used by 60%~70%, reduces water consumption by 50%~60%, and the "salt protection zone" in the rhizosphere reduces the salt content in the root zone by 30%~50%.

[0037] (3) Ecological self-stabilization. Coverage is incorporated as an active control variable into the closed-loop feedback, and smooth regulation is achieved through integral control algorithm to break the vicious cycle of "salt damage - sparse vegetation - increased salt return" and realize the active regulation of the ecosystem.

[0038] (4) Synergistic effect. The three core modules form a four-in-one closed-loop system of "seed source-water-salt-coverage", with a synergy coefficient of over 1.60, a coverage of 71% in 120 days, an annual biomass of 3.7 t / ha, a root layer pH of 9.8 to 8.3, and an EC of 4.2 dS / m to 2.6 dS / m, achieving the rapid restoration goal of "sowing in the same year, establishing turf in the same year, stabilizing in two years, and self-sustaining in three years". Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0040] Figure 1 This is an overall flowchart of the technical solution of the present invention;

[0041] Figure 2 This is a schematic diagram of the cross-section of the seed source island transplantation.

[0042] Figure 3 This is a schematic diagram of the structure of an organosilicon functional liquid-drip irrigation coupling system;

[0043] Figure 4 This is a graph showing the water potential-time relationship between the three stages of irrigation regulation. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] like Figure 1 As shown, the method of the present invention includes four core steps:

[0046] Step 1 involves targeted collection and acid activation pretreatment of the soil seed bank. Specifically, topsoil from the native vegetation area of ​​the soda saline-alkali grassland is collected from late March to early April, moistened with dilute hydrochloric acid solution, and then sealed to obtain acid-activated seed bank substrate.

[0047] Step two involves the preparation of composite transplanting substrate and the establishment of seed source islands. In mid-to-late April, the activated seed bank substrate is mixed with desulfurized gypsum, zeolite powder, and decomposed organic fertilizer in a specific ratio and then placed in the remediation area in the form of seed source islands.

[0048] Step 3 involves the deployment of the organosilicon functional liquid-drip irrigation coupling system and intelligent water and salt regulation. In the same period as step 2 (mid to late April), drip irrigation tapes are laid under the seed source island and equipped with organosilicon functional liquid injection devices. Three-stage irrigation regulation is implemented based on data from soil moisture and salt sensors.

[0049] Step four is dynamic integral feedback control of vegetation cover, which involves periodically measuring vegetation cover during the growing season (between May and August) and using a closed-loop ratio integral control algorithm for cover feedback control.

[0050] The four steps are functionally coupled through a four-in-one closed-loop control system of "seed source-water-salt-coverage". Among them, the third and fourth steps have a two-way interactive relationship, indicating that there is dynamic synergy between irrigation regulation and coverage feedback.

[0051] Figure 2 A cross-sectional structure of the seed island transplantation is shown. (For example...) Figure 2 As shown, the seed island is formed by filling a pit (12-15 cm in diameter, 5-8 cm deep) or trench in the remediation area with a composite transplanting matrix. After the matrix is ​​implanted, the surface is covered with 1-2 cm of soil. Pressure-compensated drip irrigation tape is buried 10-15 cm below the seed island, with a dripper spacing of 20-25 cm and a single dripper flow rate of 1.2-1.8 L / h. Moisture sensors and salinity sensors (EC probes) are layered at soil depths of 5 cm, 15 cm, and 25 cm to form a real-time monitoring network. Irrigation water containing organosilicon functional liquid is precisely released from the drippers into the root zone of the seed island, forming a "diluted salinity protective zone" microenvironment in the rhizosphere soil.

[0052] Figure 3 The specific structure of the silicone functional liquid-drip irrigation coupling system is shown. For example... Figure 3 As shown, the system includes a water source, a filter (150 mesh), a fertilizer injection device, an acid injection device, and a drip irrigation tape, all connected sequentially by pipelines. An organosilicon functional liquid injection point is installed between the filter and the fertilizer injection device on the pipeline, which can be injected using a booster pump (injection pressure 0.10~0.15 MPa). A multi-stage filtration system (120 mesh and 200 mesh disc filters) is installed at the injection point. An automatic backwashing circuit is also provided, connected to the filter by the drip irrigation tape. The system automatically backwashes every 48 hours (flushing pressure 0.15~0.20 MPa, lasting 3~5 minutes) to prevent the organosilicon surfactant from forming a biofilm and clogging the pipeline.

[0053] Figure 4 The water potential-time relationship of three-stage irrigation regulation is shown. Figure 4As shown, the horizontal axis represents the growing season duration (days), and the vertical axis represents the rhizosphere soil water potential (kPa). During the leaching stage (days 0-20): the water potential was maintained in the range of -5 to -10 kPa, supplemented with high-volume addition of organosilicon functional liquid (0.8-1.2 L / acre·time) and large-scale irrigation (15-25 m³ / day). 3 / mu), focusing on rhizosphere salt leaching; adaptive regulation phase (days 21-120): water potential is raised to the range of -10 to -15 kPa, the dosage of organosilicon functional liquid is reduced to 0.4-0.6 L / mu·time, and the single irrigation volume is 10-15 m³. 3 / mu, EC target range 1.5~2.5 dS / m; Deficiency induction stage (after 121 days): Water potential further decreases to -15~-20 kPa range, organosilicon functional liquid dosage decreases to 0.2~0.3 L / mu·time, single irrigation volume 8~10 m 3 / acre, extend the drying time to 2-3 days, and use moderate drought stress to promote root development.

[0054] The technical solution of the present invention will be further illustrated below with specific implementation examples.

[0055] Example 1

[0056] Implementation location: Da'an City, Baicheng City, Jilin Province (pH 9.8, EC 4.2 dS / m, soil bulk density 1.52 g / cm³) 3 (Organic matter 0.8%).

[0057] Implementation scale: 5 mu.

[0058] Implementation steps:

[0059] Late April: Collect the top 0-10 cm soil from the nearby native sheepgrass meadow, air dry and remove impurities, spray with diluted hydrochloric acid at pH 2.0 to moisten to 60% of field capacity, and let stand in a sealed container for 72 hours.

[0060] Prepare the composite transplanting substrate: 62% activated seed bank substrate + 12% desulfurized gypsum + 14% zeolite powder + 12% well-rotted organic fertilizer (by weight), mix evenly.

[0061] Drip tape installation: burial depth 12 cm, spacing 45 cm, dripper spacing 25 cm, single dripper flow rate 1.5 L / h; install a set of moisture / EC sensors at depths of 5, 15, and 25 cm.

[0062] Seed island establishment: density 1.8 seeds / m² 2 The holes are 15 cm in diameter and 6 cm deep. About 200g of substrate is implanted in each hole and covered with 1.5cm of soil.

[0063] Organosilicon functional liquid: non-ionic organosilicon surfactant, the surface tension of irrigation water after injection is 48±2 mN / m (measured by Wilhelmy plate method).

[0064] Leaching stage (0-20 days): When the water potential is -5 to -10 kPa and EC > 4.0 dS / m, add acid to adjust the pH to 6.8 ± 0.2. Use 1.0 L / mu per irrigation. Each irrigation should cover 18-22 m³. 3 / mu, once every 2 days.

[0065] Adaptive regulation phase (21-90 days): water potential -10 to -15 kPa, target EC 1.5-2.5 dS / m, organosilicon 0.5 L / mu·time, single irrigation 12-14 m. 3 / mu, once every 3-4 days. The first mowing is on July 15 (when the coverage is about 45%), leaving a stubble of 9cm. Irrigate 12% within 24 hours after mowing.

[0066] Deficiency induction stage (after 91 days): Water potential -15 to -20 kPa, organosilicon 0.25 L / acre·time, single irrigation 8~10m 3 Apply per acre, once every 5-7 days, and allow to dry for 2-3 days.

[0067] Coverage monitoring: Multispectral measurements by UAV every 10 days, using an integral control algorithm (C min =55%, C max =75%) Automatic adjustment.

[0068] Sensor data fusion and conflict handling use 15 cm depth sensor data as the primary control basis. During implementation, when the EC difference between 5 cm and 15 cm depths was >1.5 dS / m (occurring 3 times), the controller automatically adjusted the drip irrigation frequency from once every 3 days to once every 2 days. After processing, the average EC reduction at the surface layer reached 1.2 dS / m, and the difference returned to within the threshold. When the EC at 25 cm depth was consistently lower than that at 15 cm depth (occurring 2 times), the controller automatically increased the single irrigation volume by 20%. After processing, the average EC reduction at 15 cm depth was 0.4 dS / m, significantly improving rinsing efficiency. When sensor data conflict occurred (occurring 1 time), the controller used the 15 cm depth data as the standard for irrigation decisions and triggered a system alarm. Manual investigation revealed poor sensor contact; after reinstallation, the data returned to normal.

[0069] The final harvest was carried out in late September, leaving a 13 cm stubble for overwintering.

[0070] Comparative Example 1

[0071] The control treatment used the local conventional methods for restoring saline-alkali grasslands, and the specific procedures are as follows:

[0072] (1) Application of soil amendment and tillage in mid-April: Apply 1000 kg of desulfurized gypsum and 2000 kg of well-rotted farmyard manure per mu, and carry out deep tillage using a grid-type hydraulic reversible plow to a depth of 25-30 cm. -1 Mix the soil amendment thoroughly with the soil. After tilling, use a rotary tiller to break up the soil and level it.

[0073] (2) Sowing in late April: Select salt-tolerant forage grass seeds (a mixture of alkali grass, alkali grass, and sheep grass in a ratio of 2:1:1)-2, and broadcast at a rate of 2.5 kg / mu. After sowing, cover with soil shallowly for 1-2 cm and lightly compact.

[0074] (3) Irrigation management: Flood irrigation is adopted. Depending on soil moisture and weather conditions, irrigation is carried out 4 to 6 times during the growing season (May to September), with each irrigation volume being 60 to 80 m³. 3 / mu, with an annual irrigation volume of approximately 350~400 m³. 3 / mu.

[0075] (4) Fertilizer management: Apply 10 kg / mu of urea in mid-June.

[0076] (5) Harvesting management: Harvest once in late September, leaving a stubble of 5-8 cm.

[0077] (6) Management in the following year and thereafter: In the spring of the second year, artificial reseeding (mixed grass seeds in the same proportion, sowing amount 1.5 kg / mu) will be carried out in the areas lacking seedlings. The irrigation method will remain flood irrigation, and fertilization will be the same as in the first year. From the third year onwards, only fencing and annual mowing will be maintained, and no more artificial reseeding and fertilization will be carried out.

[0078] Table 1. Implementation Results in the First Year

[0079] deal with Example 1 Comparative Example 1 Increase (%) Emergence time (d) 15 21 28.6 60-day coverage (%) 42 12 250.0 120-day coverage (%) 71 35 102.8 150-day coverage (%) 73 45 62.2 Annual biomass (t / ha) 3.7 2.1 76.2 Root layer pH 8.3 9.4 11.7 Root layer EC (dS / m) 2.6 3.8 31.6 Total amount of organosilicon used (L / mu) 4.1 - - <![CDATA[Water for drip irrigation (m 3 / mu)]]> 165 385 57

[0080] In the first year, the proposed method achieved a significant increase in vegetation cover to 73%, while the control group only recovered to 45%. Regarding soil improvement, the proposed method reduced root zone pH from 9.8 to 8.3 (compared to 9.4 in the control group) and EC from 4.2 dS / m to 2.6 dS / m (compared to 3.8 dS / m in the control group), demonstrating significantly better soil improvement results than the control.

[0081] Table 2. Implementation Results in the Second Year

[0082] deal with Example 1 Comparative Example 1 Increase (%) Spring greening rate (%) 93 58 60.3 Coverage (%) 81 34 138.2 Annual biomass (t / ha) 5.2 2.6 100.0 Root layer pH 8.1 9.1 11.0 Root layer EC (dS / m) 2.4 3.5 31.4 Percentage of sheepgrass (%) 76 22 245.5 Total amount of organosilicon used (L / mu) 0.9 - - <![CDATA[Water for drip irrigation (m 3 per mu)]]> 112 360 68.9

[0083] In the second year, the vegetation cover of the proposed solution stabilized at over 80%, with Leymus chinensis becoming the dominant species (accounting for 76%), and the grassland community structure tended to stabilize. Although the control treatment showed some recovery, Leymus chinensis accounted for only 22%, and the community was still dominated by degraded indicator plants such as Suaeda salsa and Suaeda salsa. The irrigation water consumption of the proposed solution was further reduced to 112 m³ / acre, only 31% of the control, and the amount of organosilicon used decreased by 78% compared to the first year, demonstrating the self-sustaining capability of the technical solution.

[0084] Table 3. Implementation Results in the Third Year

[0085] deal with Example 1 Comparative Example 1 Increase (%) Spring greening rate (%) 95 52 82.7 Coverage (%) 83 31 167.7 Annual biomass (t / ha) 5.4 2.4 125.0 Root layer pH 8.0 9.0 11.1 Root layer EC (dS / m) 2.3 3.4 32.4 Percentage of sheepgrass (%) 82 18 192.9 Total amount of organosilicon used (L / mu) 0.3 - - <![CDATA[Water for drip irrigation (m 3 per mu)]]> 85 340 75.0

[0086] In the third year, the Leymus chinensis cover of the proposed method stabilized at over 80%, with a fresh aboveground biomass of 5.4 tons / hectare, essentially restoring the productivity level of natural Leymus chinensis grasslands in the Songnen Plain during the 1970s and 80s. Soil pH stabilized at around 8.0, and EC stabilized at around 2.3 dS / m. Organosilicon usage was only 0.3 L / mu (a 93% reduction compared to the first year), and irrigation water usage was only 85 m³ / mu (a 48% reduction compared to the first year, and a 75% water saving compared to the control). The grassland ecosystem had entered a stable state of "low input, self-sustaining." In contrast, the vegetation cover of the control treatment consistently failed to exceed 35% over the three years, the Leymus chinensis proportion remained below 20%, and the improvement in soil pH and EC was limited, remaining in a state of moderate salinization, failing to achieve sustained grassland recovery.

[0087] Example 2

[0088] Implementation location: Taonan City, Baicheng City, Jilin Province (pH 9.7, EC 4.5 dS / m).

[0089] Implementation scale: A total of 8 pilot plots, each with an area of ​​2 mu.

[0090] Experimental Design:

[0091] deal with A (Acidic activation) B (Organosilicon-drip irrigation coupling) C (Coverage Feedback) Design Logic CK none No (conventional irrigation) none blank A have none none Single factor B none have none Single factor C none none have Single factor AB have have none Two-way collaboration AC have none have Two-way collaboration BC none have have Two-way collaboration ABC have have have Complete Solution (This Invention)

[0092] Implementation steps: Each treatment was performed according to the basic parameters of Example 1, with only the corresponding modules being turned on / off according to the experimental design. All treatments were carried out simultaneously on the same plot under consistent environmental conditions.

[0093] Implementation results:

[0094] deal with 60-day coverage / % 120-day coverage (%) Annual biomass (t / ha) Root layer pH Coordination coefficient CK 5 8 1.1 9.7 A 12 18 1.6 9.4 B 15 22 1.9 9.2 C 8 14 1.4 9.5 AB 28 45 3.3 8.7 1.46 AC 18 32 2.5 9.0 1.49 BC 22 41 3.0 8.9 1.46 ABC 35 63 4.1 8.5 1.60

[0095] Explanation of the synergy coefficient:

[0096] The synergy coefficient α of a certain indicator = actual improvement rate / (sum of improvement rates of each individual factor)

[0097] Taking 120-day coverage as an example: CK is 8%, ABC is 63%, and the actual improvement rate = 63% - 8% = 55%.

[0098] A increases by 18% - 8% = 10%, B increases by 22% - 8% = 14%, C increases by 14% - 8% = 6%, and the sum of the single-factor increases is 10% + 14% + 6% = 30%.

[0099] α 120天盖度 =55% / 30%=1.83.

[0100] The overall synergy coefficient α is the average of the synergy coefficients of each indicator.

[0101] The results show that the various technical modules of the present invention have a significant synergistic effect, and the synergy coefficient of the complete scheme reaches 1.60.

[0102] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for vegetation restoration in soda saline-alkali grassland based on precise water and salt regulation, characterized in that, Includes the following steps: Step 1: Collect topsoil from the native vegetation area of ​​soda saline-alkali grassland as a germplasm resource bank. Spray it with a dilute hydrochloric acid solution with a pH of 1.8 to 2.2 to moisten it to 55% to 65% of the field water holding capacity. Seal it and place it for 60 to 72 hours to obtain an acidic activated seed bank substrate. Step 2: Mix the acidic activated seed bank substrate with desulfurized gypsum, zeolite powder and decomposed organic fertilizer in a mass ratio of (60~65):(12~15):(12~15):(8~10) to form a composite transplanting substrate, and place seed source islands in the remediation area at a density of 1.5~2 seed source islands per square meter. Step 3: Install pressure-compensated drip irrigation tape at a depth of 10-15 cm below the seed source island, equipped with an organosilicon functional liquid injection device. Simultaneously, install a main control moisture sensor and a salinity sensor at a soil depth of 15 cm, and auxiliary moisture sensors and auxiliary salinity sensors at 5 cm and 25 cm, respectively, to construct a real-time monitoring network. The 15 cm depth sensor data serves as the primary control basis, with the 5 cm and 25 cm depth data as auxiliary references. When the EC value at 5 cm depth is higher than the EC value at 15 cm depth and the difference is >1.5 dS / m, the controller automatically increases the drip irrigation frequency to suppress surface salt return. When the EC value at 25 cm depth is consistently lower than the EC value at 15 cm depth, it indicates insufficient leaching, and the controller automatically increases the single irrigation volume by 20%. When the data from the three depth sensors conflict, the 15 cm depth data is used as the basis for irrigation decisions, and the system records anomalies. The organosilicon functional liquid is a non-ionic organosilicon surfactant, which, when added to drip irrigation water, reduces the surface tension of the irrigation water to 45-50 mN / m. Three-stage irrigation regulation is implemented based on soil sensor data: Leaching stage: Maintain rhizosphere water potential at -5 to -10 kPa, add organosilicon functional solution to drip irrigation water at a rate of 0.8 to 1.2 L / acre per application, with a single irrigation volume of 15 to 25 m³. 3 / mu; Adaptive regulation phase: Maintain rhizosphere water potential at a depth of 15 cm at -10 to -15 kPa, reduce the dosage of organosilicon functional liquid to 0.4 to 0.6 L / acre per application, and the single irrigation volume is 10 to 15 m³. 3 / mu; Deficiency induction stage: Maintain rhizosphere water potential at a depth of 15 cm at -15 to -20 kPa, reduce the dosage of organosilicon functional liquid to 0.2 to 0.3 L / acre per application, and the single irrigation volume is 8 to 10 m³. 3 / mu; Step 4: During the growing season, regularly measure vegetation cover and use a closed-loop ratio integral control algorithm for cover feedback control: set a target cover lower limit of 55% and an upper limit of 75%. When the cover is <40%, start the reseeding program and increase the drip irrigation frequency. When the cover is 40%~60%, maintain the adaptive adjustment stage parameters and perform light mowing. When the cover is >80%, start the dry-wet alternation suppression program.

2. The method according to claim 1, characterized in that, The depth of the surface soil sample collected in step one is within 15cm.

3. The method according to claim 1, characterized in that, The seed source islands described in step two are laid out by digging trenches or holes, with trenches 5-8 cm deep and holes 12-15 cm in diameter, and the substrate is covered with 1-2 cm of soil after implantation.

4. The method according to claim 1, characterized in that, In step three, the spacing of the pressure-compensated drip irrigation tape is 40-50 cm, the working pressure is 0.06-0.09 MPa, the dripper spacing is 20-25 cm, and the single dripper flow rate is 1.2-1.8 L / h; the moisture sensor and salinity sensor are installed at soil depths of 5 cm, 15 cm, and 25 cm.

5. The method according to claim 1, characterized in that, The organosilicon functional liquid mentioned in step three is selected from one or more of the following materials: MQ911 agricultural synergist, Silwet L-77, Silway 240, organosilicon polyoxyethylene ether surfactant, and water-soluble fertilizer containing organosilicon humic acid; The rinsing stage described in step three is from day 0 to day 20. When EC > 4.0 dS / m, the pH of the irrigation water is automatically adjusted to 6.5-7.

0. The conditions for switching to the adaptive control stage are: the time after transplanting is ≥ 20 days, the EC value at a depth of 15 cm is ≤ 4.0 dS / m for 3 consecutive days, and the water potential at a depth of 15 cm is stable within the range of -5 to -10 kPa for 3 consecutive days. If the EC does not meet the standard on day 20, the rinsing stage is extended by 3 days each time, and the single irrigation volume is increased by 20% until the EC meets the standard and then the stage is switched. If the target is not met by the 30th day, a system alarm will be triggered. The adaptive regulation phase lasts from day 21 to 120, with a target EC range of 1.5 to 2.5 dS / m. The conditions for switching to the deficit-inducing phase are: transplanting time ≥ 120 days, vegetation cover measured twice consecutively at 10-15 day intervals with values ​​≥ 55%, and EC values ​​at a depth of 15 cm ≤ 2.5 dS / m for 7 consecutive days. If the vegetation cover does not meet the target by day 120, the adaptive regulation phase is extended by 15 days each time, maintaining the current irrigation parameters until the target vegetation cover is met before switching. If the target is still not met by day 150, a reseeding procedure is triggered. The deficit induction phase is after 121 days, during which EC is allowed to rise below 3.0 dS / m, and the drying time is extended to 2-3 days.

6. The method according to claim 1, characterized in that, The vegetation cover measurement frequency in step four is every 10-15 days, using UAV multispectral imagery or ground photography; the reseeding procedure is as follows: composite transplanting substrate at 80-120 g / m² 2 Broadcasting and drip irrigation frequency increased to 1-2 times per day to maintain water potential at -5 to -8 kPa; light mowing is done once a month, leaving a stubble of 8-10 cm, and the drip irrigation volume is increased by 10%-15% within 24 hours after mowing.

7. The method according to claim 1, characterized in that, The wet-dry alternation suppression procedure described in step four is as follows: stop irrigation for 5 to 7 days until the soil water potential is below -40 kPa, then resume irrigation until the water potential is -12 to -15 kPa. Thereafter, repeat the wet-dry alternation cycle every two weeks until the soil cover falls back to below 75%.

8. The method according to claim 1, characterized in that, The organosilicon functional liquid mentioned in step three is added through the injection line at the end of the drip irrigation system. The injection point is located after the filter and before the valve, and the injection pressure is 0.10~0.15 MPa.

9. The method according to claim 8, characterized in that, The drip irrigation system starts an automatic backwashing program every 48 hours of operation, lasting for 3 to 5 minutes at a flushing pressure of 0.15 to 0.20 MPa, and flushes the pipeline with clean water for 2 to 3 minutes after each injection.

10. The method according to claim 1, characterized in that, The organosilicon functional liquid is pre-filtered using a multi-stage filtration system, which includes 120-mesh and 200-mesh disc filters, and an online screen filter with a precision of 150 mesh is installed at the injection port of the drip irrigation system.

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