CN114375751B

CN114375751B - Method for repairing coastal saline-alkali field and application thereof

Info

Publication number: CN114375751B
Application number: CN202111623878.7A
Authority: CN
Inventors: 江良为; 罗伟聪; 董运常; 刘贵才
Original assignee: Huayuan Landscape Architecture Co ltd
Current assignee: Huayuan Landscape Architecture Co ltd
Priority date: 2021-12-28
Filing date: 2021-12-28
Publication date: 2023-05-09
Anticipated expiration: 2041-12-28
Also published as: CN114375751A

Abstract

The invention discloses a method for repairing a coastal saline-alkali field and application thereof, and belongs to the technical field of plant resource development and utilization. The method for repairing the coastal saline-alkali soil comprises the following steps of: (1) field arrangement and improvement: (2) planting plants; (3) layering and root promotion; (4) watering and fertilizing; (5) saline-alkali soil restoration; (6) post-treatment of plants. The method for repairing the coastal saline-alkali soil of the invention is used for planting the single-leaf fructus viticis in the saline-alkali soil to increase the earth surface coverage, reduce the soil moisture evaporation, increase the soil organic matter content, improve the soil structure and the biological activity and the like, and the excellent characteristics of the single-leaf fructus viticis are utilized to plant the single-leaf fructus viticis with high salt tolerance in the seashore area, so that the effects of greening, wind prevention and sand fixation can be achieved, the coastal saline-alkali soil can be improved in a low cost and large range, the good ornamental effect can be achieved, and the economic value and the ecological value are very remarkable.

Description

Method for repairing coastal saline-alkali field and application thereof

Technical Field

The invention relates to the technical field of plant resource development and utilization, in particular to a method for repairing a coastal saline-alkali field and application thereof.

Background

Vitex agnus-castus (Vitex agnifolia) is a shrub of Vitex genus (Vitex) of Labiatae family, and the stem is creeping, adventitious roots are frequently grown at knots. Single-leaf contra-generation, inverted oval or nearly circular, full edge; the conical inflorescences grow on the tops, the inflorescences are densely covered with grey-white fluff, and the corolla is light purple or blue-purple. The stone fruit is nearly round, has a diameter of about 5 mm, and is black when ripe. The products of North China, east China, south China coast and the like are usually in beach, seaside and lakeside. Flowering period is 7-8 months, and fruit period is 8-10 months. The single leaf fructus viticis grows fast, has developed root system, has the depth reaching more than 3m of soil layer, has strong salt tolerance, and is drought-resistant and barren; the vine is strong, the stolons can quickly cover the ground and form communities, and the plant has strong capability of fixing sand, resisting salt, resisting sea wind and sea fog, and is one of pioneer plants for fixing sand and making green in coastal areas.

At present, research reports on the fructus viticis are mainly concentrated on the aspects of physiological active ingredients, medicinal value, genetic diversity analysis, seed dormancy characteristics, nutrition propagation technology and the like, few research reports on the saline-alkali soil restoration are provided, and few salt stress test researches show that the salt tolerance of the fructus viticis is only 1.0% at maximum. Meanwhile, the single leaf fructus viticis seeds have dormancy characteristics and are difficult to germinate, so that the seedlings are propagated in a cutting mode in production, but the roots of the cutting seedlings are shallow and floating, and the repairing requirements of different soil depths of saline-alkali soil are difficult to meet. Therefore, the single leaf vitex plant seedlings with high salt tolerance are fully screened and bred and used for soil remediation of coastal saline-alkali sites, and the method has important economic and ecological values.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for repairing a coastal saline-alkali field and application thereof.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the method for repairing the coastal saline-alkali field comprises the following steps of:

(1) Field arrangement and improvement: ploughing and raking up the field;

(2) Planting plants: placing the high-salt-tolerance single-leaf vine Jing Shi container seedling into a planting hole, backfilling with raw soil, and timely watering to fix root;

(3) Root promotion by layering: pressing down the main stem of the single leaf fructus viticis to the plant row spacing of the ground, fixing the pressed stem section with a U-shaped ground nail at the position which is 10 cm to 15 cm close to the root, so that the main stem creeping along the ground;

(4) Watering and fertilizing;

(5) Repairing a saline-alkali field;

(6) Post-treatment of plants: and after the site repair is finished, the whole plant is excavated and uniformly recovered.

The invention aims to provide a complete set of technical methods for seed source screening, seedling breeding and ecological restoration planting of high salt tolerance of the viticis single-leaf, and solve the problems of low salt tolerance of the viticis single-leaf, difficult seedling breeding, blind and unordered ecological restoration of saline-alkali soil and low desalination rate.

As the preferred implementation mode of the method for repairing the coastal saline-alkali soil, the soil arrangement and improvement in the step (1) further comprises the steps of carrying out the treatment on each 667m ² Applying 40-60 kg of nitro compound fertilizer to the field of the soil, and applying the nitro compound fertilizer to the strong alkaline soil with the pH value of more than 8.5, wherein each 667m ² Spraying 500L of 0.02-0.04% humic acid solution.

In the field arrangement and improvement measures adopted by the invention, the physical properties of the saline-alkali soil can be improved by ploughing and raking, and the conduction and accumulation of underground salt along the capillary pore of the soil to the ground are blocked. The deep Shi Xiaoji compound fertilizer can improve the application effect of alkaline soil on the fertilizer and improve the nutrition condition of the soil. The humic acid fertilizer with proper concentration is applied to the strong alkaline soil, so that the alkalinity of the soil can be neutralized, the salt ion activity of the saline-alkali soil can be reduced, and a good soil environment can be created for plant roots.

As a preferred implementation mode of the method for repairing the coastal saline-alkali soil, in the step (3), the phloem of 1-3 cm is cut off from the downward part of the stem node every 20-30 cm, then the stem node is covered with the wetting agent river sand with the water content of 20%, and the sand covering height is 3-5 cm.

The layering root promotion method adopted by the invention can accelerate the germination of adventitious roots on stolons, the segmented root promotion treatment can more effectively increase the total root system quantity in unit area, and the full coverage of saline-alkali soil can be realized as soon as possible. The straight root system of the single leaf fructus viticis is strong and thick and long, has strong geotropic property and strong solidity, can be pricked into the deep part of the saline-alkali soil, and can greatly enhance the absorption and enrichment effects of the plant total root system on soil salt ions together with dense adventitious root clusters distributed on shallow layers, thereby accelerating the ecological restoration of the field.

According to the method for repairing the coastal saline-alkali soil, the soil drought condition is considered at the initial stage of field planting, and the soil is manually irrigated for 1-2 times; the natural precipitation is adopted in rainy season, irrigation is not needed in other periods, and labor and maintenance cost can be saved. The compound aqueous solution fertilizer of 0.005% -0.01% of brassin and 0.6% -1.2% of urea is sprayed on leaf surfaces in spring for 1-2 times, so that the stress resistance of seedlings to saline-alkali soil in the early stage of planting can be enhanced, and the photosynthesis efficiency can be improved; the foliar fertilizer is sprayed with 1.0% -2.0% of calcium superphosphate aqueous solution fertilizer for 2-3 times in summer and autumn, so that the adaptability of the fructus viticis alone to different saline-alkali soil can be improved, and the vigorous growth of plants can be promoted. The contact between the fertilizer and the soil can be reduced by adopting a foliar fertilization mode, and the adverse effect of aggravation of soil salt injury caused by root fertilization is effectively avoided.

As the preferred implementation mode of the method for repairing the coastal saline-alkali soil, the method for screening the seed source of the high-salt-tolerance fructus viticis comprises the following steps:

(1) Selection of panelists: selecting sand, sheet or strip distribution near sea and area over 50m ² The wild species group of the vitex agnus-castus is a investigation object;

(2) Screening of candidate single strains: selecting robust plants with luxuriant branches and leaves as candidate single plants in a survey object;

(3) Screening of target single plants: selecting a candidate single plant with the soil EC value exceeding 18 (mS/cm) within the root 20cm range as a target single plant;

(4) Screening of excellent seed sources with high salt tolerance: selecting a target single plant with the soil total salt content of more than 1.0%, and taking the excellent single plant as a circle center, wherein plants with the radius of 4-8 m are excellent seed sources of the single-leaf fructus viticis with high salt tolerance.

As a preferred implementation mode of the method for repairing the coastal saline-alkali soil, the distance between wild species of the fructus viticis alone is more than 5km, and the distance between each candidate single plant is more than 20 m.

The wild single-leaf vitex agnus-castus population in the seaside high-salt sand division is selected as a seed source, the wild single-leaf vitex agnus-castus population has higher salt adaptability and salt tolerance than the wild single-leaf vitex agnus-castus population screened by the conventional seed source, and robust plants which are separated by a certain distance in the wild single-leaf vitex agnus-castus population are taken as candidate single plants, so that the influence of local topography difference on the salt content of soil can be eliminated, the salt tolerance consistency and stability of a screening target are ensured, and the better single plants or the single-leaf vitex agnus-castus population with higher salt tolerance can be further screened; according to the invention, soil EC value detection is adopted to indirectly screen target single plants, the EC value reflects the concentration of soluble salt in soil, the higher the EC value is, the stronger the salt tolerance of the corresponding single plants is, and the salt tolerance of the target single plants is analyzed through the conductivity of soil sample leaching liquor, so that the accurate single-leaf fructus viticis seed sources with high salt tolerance are screened. The method avoids the problem that the conventional instrument and equipment cannot directly detect the salt content of the soil, combines simple and rapid field screening with quantitative laboratory analysis, and ensures that the seed source screening is more efficient and accurate; according to the determination result of the total salt content of the soil sample and referring to the Guangdong soil salinization standard and the general soil standard in the garden greening industry, the sample land grade and the salt-tolerant grade are reasonably divided, and the method is more suitable for the restoration requirement of the saline-alkali soil in the Zhu-delta area. The target single plant for screening the severe salinized sample with the total salt content of more than 1.0% is an excellent single plant with high salt tolerance, which is higher than the maximum salt tolerance value of 1.0% reported by the current single leaf vitex agnus-castus salt stress test research. The soil where the plants with the radius of 4-8 m are located and the soil in the sample side have similar total salt content, namely consistent salt tolerance, by taking the excellent single plant as the center of a circle, all the plants in the range can be identified as single-leaf fructus viticis seed sources with high salt tolerance, so that enough seed collection quantity is ensured.

As the preferred implementation mode of the method for repairing the coastal saline-alkali soil, the method for breeding the seedlings of the high-salt-tolerance single-leaf fructus viticis comprises the following steps:

(1) Seed pretreatment: soaking the seeds in clear water for 1-2 h, removing gray brown calyx and fuzz on the surfaces of the seeds, soaking the seeds in 0.2% potassium permanganate solution for 10min, washing the seeds with clear water for 2-3 times, and draining water

(2) Seed germination accelerating treatment: soaking seeds 3-h in a first-concentration acetic acid solution, soaking the seeds for 1-3 hours in a second-concentration acetic acid solution, taking out the seeds, cleaning, and continuously soaking the seeds in a GA3 solution for 12-h;

(3) Plug seedling: sowing and raising seedlings by adopting a 72-hole tray, wherein a sowing matrix is pure vermiculite with the grain diameter of 1-2 mm or special nutrient soil for sowing, 2 seeds are sown in each hole, and 1500 times carbendazim solution is used for thoroughly watering after sowing;

(4) Seedling salinization induction: after sowing for 2 weeks, pouring the matrix by adopting NaCl solution, pouring for 2 times continuously every 10 days, and uniformly spraying NaCl mist aqueous solution to the surfaces of the seedlings for 1 time every 7 days and continuously spraying for 2-3 times when more than 2 pairs of young leaves are formed;

(5) Transplanting seedlings: subpackaging a transplanting matrix into a nutrition cup, transplanting seedlings in a plug into the nutrition cup, and then thoroughly watering a fixed root with 800-1000 times carbendazim solution;

(6) And (3) strong seedling cultivation: after field planting for 2 weeks, spraying 9.0-15.0 g/L N every 20-30 days in the vigorous growth period in spring and summer: p: k=23: 11:14, wherein the composite water solution fertilizer is continuously sprayed for 3-6 times; 10 days before seedling, irrigating or spraying 0.2% NaCl solution on the root or leaf surface of the plant for 1-2 times to obtain strong single leaf vine Jing Shi seedling with high salt tolerance;

(7) And (5) nursery stock is transplanted.

The invention separates seedling cultivation and strong seedling cultivation, and can ensure the cultivation efficiency and seedling quality of each stage. The small-particle pure vermiculite adopted by the sowing matrix is loose, breathable and water-retaining, so that the germination rate of seeds is improved; the transplanting adopts a compound matrix composed of garden soil, peat soil, sea sand and farmyard organic fertilizer, so that the transplanting has high organic matter content, is loose and breathable, and is very suitable for expanding seedling root systems and nutrient growth of plants.

As a preferred embodiment of the method for repairing a coastal saline-alkali soil of the present invention, in the step (2) of the method for breeding seedlings of high salt-tolerant single leaf chaste tree, the concentration of the first concentration acetic acid solution is 5%, the concentration of the second concentration acetic acid solution is 2.5%, and GA ₃ The concentration of the solution is 50-100 mg/L.

The invention adopts 5 percent acetic acid solution to soak seeds, which can effectively break the physical dormancy caused by the bolting of the seed coats, GA ₃ The solution can be used for soaking seeds to effectively reduce the physiological activity inhibition caused by endogenous substances of seed coats. Compared with the pickling treatment of the single leaf fructus viticis seed by using concentrated sulfuric acid, the acetic acid adopted by the invention belongs to conventional chemicals, is not controlled by dangerous chemicals, is easy to purchase, is safe to operate, and can be replaced by common white vinegar. By acid etching with proper concentration of acetic acid and GA ₃ The treatment can accelerate the germination of seeds, and the germination rate of the seeds is up to 81.9%.

As a preferred embodiment of the method for repairing the coastal saline-alkali soil, the concentration of the NaCl solution in the step (4) of the method for breeding the seedlings of the high-salt-tolerance fructus viticis is 0.2%.

The invention adopts the method of pouring the matrix with the low-concentration NaCl solution and spraying the seedlings, can induce the seedlings to form stable salt tolerance, and ensures that the seedlings adapt to the sea sand salt in the transplanted matrix and the soil environment of the alkali field of the salt to be repaired in time, thereby improving the salt tolerance of the seedlings and the repair effect of the field.

As the preferred implementation mode of the method for repairing the coastal saline-alkali soil, the transplanting matrix in the step (5) of the method for breeding the seedlings of the high-salt-tolerance single-leaf fructus viticis is formed by mixing garden soil, peat soil, sea sand and farmyard organic fertilizer in a volume ratio of 4:2:3:1, wherein the salt content of the sea sand is less than 3%.

The transplanting matrix adopted by the invention comprises 30% of sea sand, the sea sand is an important formula of the matrix, the salt content of the sea sand is preferably controlled within 3%, and the sea sand with proper proportion and salt content is adopted as a mixed matrix because the sea salt content of the sea sand is consistent with the sea saline-alkali soil content of the coastal, so that the salt adaptability and salt tolerance of the single leaf vitex agnus seedlings can be induced, and the activity of the root systems of the seedlings and the adaptability after repair planting are improved. The strong seedling cultivation method of spraying the composite water solution fertilizer on the leaf surface can improve photosynthesis and stress resistance of plants, supplement the deficiency of root nutrients while strictly controlling the concentration of matrix salt ions, and promote vigorous growth of overground parts and underground parts of plants so as to obtain the strong seedlings of the single leaf tendrils Jing Shi with high salt resistance.

The invention also provides an application of the method for repairing the coastal saline-alkali field in the coastal saline-alkali field repair.

The invention has the beneficial effects that: the invention provides a method for repairing a coastal saline-alkali soil, which comprises a complete set of technical methods of seed source screening, seedling breeding and ecological restoration planting of high-salt-tolerance single-leaf fructus viticis, wherein the salt tolerance of the screened excellent seed sources of the single-leaf fructus viticis is more than 1.0%, the germination rate of bred seedlings is up to 81.9%, and the average desalination rate of the adopted saline-alkali soil ecological restoration method after one year of planting is up to 20.93%, so that the problems of low salt tolerance of the single-leaf fructus viticis, difficult germination of the seedlings, blind and unordered ecological restoration of the coastal saline-alkali soil and poor desalination effect are effectively solved. In addition, the method for repairing the coastal saline-alkali soil of the invention can be used for planting the single-leaf fructus viticis in the saline-alkali soil to increase the surface coverage, reduce the evaporation of soil moisture, increase the organic matter content of the soil, improve the soil structure and the biological activity and the like, and the excellent characteristics of the single-leaf fructus viticis are utilized to plant the single-leaf fructus viticis with high salt tolerance in the seashore area, so that the effects of greening, wind prevention and sand fixation can be achieved, the coastal saline-alkali soil can be improved in a low cost and large range, the good ornamental effect can be achieved, and the economic value and the ecological value are very remarkable.

Drawings

Fig. 1: wild communities of vitex agnus single leaf on beach sand in the bead triangle area;

fig. 2: fine single plant of single leaf vitex agnus on beach sand and mature seed thereof;

fig. 3: salt tolerance test of the single leaf vine Jing Shi raw seedling;

fig. 4: propagating seedling of high-salt-tolerance single-leaf fructus viticis in a container;

fig. 5: collecting soil samples of the coastal sand and the saline-alkali land, leaching, and detecting and analyzing total salt;

fig. 6: the coastal saline-alkali field to be repaired in the bead triangle area is turned over;

fig. 7: the creeping stems formed by the repair and planting of the high-salt-tolerance single-leaf fructus viticis.

Detailed Description

The above-described aspects of the present invention will be described in further detail below with reference to specific embodiments in the form of examples.

Example 1 seed Source screening of high salt tolerant Vitex agnus-castus

1. Referring to literature data, the distribution situation of the single leaf fructus viticis in the bead triangle coastal area is primarily clarified, and the field investigation of the single leaf fructus viticis population is carried out on Guangzhou, dongguan, shenzhen, huizhou, zhongshan, zhuhai and Jiangmen 6 cities.

2. Wild species of Vitex agnus-castus close to the coastal beach and vigorous growth were selected as shown in FIG. 1. Investigation of several growth areas per field over 50m ² Ensuring that each population is more than 5km away from each other; and selecting 1-5 robust plants with luxuriant branches and leaves as candidate single plants in each population, and ensuring that the distance between each candidate single plant is more than 20 m.

3. And (3) taking the candidate single plants as the centers, measuring the soil EC value of each candidate single plant root by using a soil EC tester, selecting candidate plants with the soil EC value exceeding 18.0 (mS/cm), and marking the candidate plants as target single plants.

4. Taking a target single plant as a center, making a 2m multiplied by 2m sample, excavating and sampling at four corners of a sample area, taking soil with a depth of 0-30 cm, weighing 200-300 g of the soil sample at each corner, bagging together, marking and then carrying the soil sample back to a laboratory. Uniformly mixing 4 parts of soil samples of each target single plant, airing, crushing, sieving by a 120-mesh screen, uniformly mixing 20g of sieved fine soil with 100ml of distilled water by adopting a leaching method, fully oscillating and standing for 2 hours, and measuring the total amount of soluble salt in the soil sample filtrate by using a conductivity analyzer.

5. The target single plant with the total salt content of more than 1.0% in the sample plot is selected as the excellent single plant with high salt tolerance, and the excellent single plant is used as the center of a circle, and plants or groups with the radius of 4-8 m are selected as the excellent seed sources of the single leaf fructus viticis with high salt tolerance, as shown in figure 2. Mature seeds are collected from the excellent seed sources for seedling cultivation.

6. The screening statistics are shown in table 1.

TABLE 1 seed Source investigation and screening statistics of high salt tolerant Vitex agnus-castus

As can be seen from table 1: 33 wild single-leaf vitex plant groups meeting the requirements are investigated in the coastal 6 city of the bead triangle, 136 candidate single plants are selected from the wild single-leaf vitex plant groups, and 64 target single plants are primarily screened from the candidate single plants through on-site soil EC value detection; and then carrying out soil sampling and detection analysis on 64 target single plants, and finally screening out 31 excellent single plants of the viticis fructus meeting the high salt tolerance requirement. The number of excellent single plants accounts for 22.8% of the total number of candidate single plants, the total salt content ranges from 1.04% to 1.79%, the excellent single plants are all wild high-salt-tolerance plants on the heavy salinized sand, and the salt tolerance of the excellent single plants is far more than the salt tolerance extreme value (the total salt content of soil is less than or equal to 0.6%) of the normal growth of garden greening plants. Therefore, the high-salt-tolerance fructus viticis screened by the method has wide soil adaptability and the practicability of saline-alkali field restoration.

Example 2 seeding and seedling raising of high salt tolerant Single leaf Vitex

In the embodiment, mature seeds are collected from the excellent seeds of the high-salt-tolerance single-leaf fructus viticis obtained by screening in the embodiment 1 for sowing and seedling raising.

1. Seed germination test

Seed pretreatment: selecting full seeds, soaking the seeds in clear water for 1-2 hours, rubbing the gray brown calyx and fuzz on the surfaces of the seeds by hands during the soaking, and picking out empty shells and impurities on the surface layer of the clear water. And fishing out the cleaned seeds, soaking and sterilizing the seeds for 10min by using 0.2% potassium permanganate solution, washing the seeds for 2-3 times by using clear water, and draining water. The seed of Vitex agnus-castus is hard to germinate due to mechanical disorder of seed coat and endogenous inhibitor of pericarp, and the seed coat disorder is broken by adopting methods of soaking in clear water, soaking in constant-temperature water bath, pickling with acetic acid solution, and the like, gibberellin (GA) ₃ ) Removing seed dormancy by methods such as wet sand layering treatment, performing seedling test by adopting a 72-hole sowing hole tray, and dibbling 1 seed per hole by adopting pure vermiculite with the particle size of 1-2 mm as a sowing matrix; normal moisture management is performed during this period until the seeds germinate.

The germination test treatments were as follows:

(1) Soaking seeds in normal-temperature clear water for 48 hours, and directly sowing;

(2) Soaking seeds in a water bath with constant temperature of 50deg.C for 12 hr, and respectively soaking seeds in 50mg/L and 100mg/L GA ₃ Soaking seeds in the solution for 12 hours and 24 hours;

(3) Soaking seeds in a water bath kettle with constant temperature of 50 ℃ for 12 hours, and respectively layering and treating the seeds with 20% of hygromycin river sand for 30d and 60d;

(4) Soaking seeds in 2.5-5.0% acetic acid for 3-6 hr, and respectively soaking seeds in 50mg/L and 100mg/L GA ₃ Soaking seeds in the solution for 12 hours and 24 hours;

(5) And (3) adopting the wet element river sand with the water content of 25% to laminate and treat the seeds for 90d, and directly seeding the seeds after the seeds are exposed. For each test treatment, 72 seeds were sown 45 and d for each treatment and the statistical germination was shown in table 2.

TABLE 2 germination acceleration treatments and germination percentage statistics

As can be seen from Table 2, the germination rate of the seeds of Vitex agnus-castus is affected differently by different germination accelerating modes, and compared with the normal-temperature seed soaking in clear water, the water bath seed soaking, acetic acid etching and gibberellin and wet sand lamination treatment can effectively remove dormancy of the seeds and improve the germination rate of the seeds. Wherein acetic acid etching and GA ₃ The germination rate of the seed soaking combined treatment is obviously superior to that of other treatment modes, and the acetic acid etching can effectively break down mechanical barriers caused by the bolting of seed coats and woods, and GA ₃ Soaking can reduce endogenous hormone in seed coat to inhibit germination, and the combined treatment of the two can remarkably improve water absorption expansion rate and final germination rate of seed, and soaking the seed with 5% acetic acid for 3h+2.5% acetic acid for 3h+50 mg/L GA ₃ The germination effect of soaking seeds for 12 hours is best, and the germination rate is up to 81.9%.

2. Seedling salinization induction

And (3) pouring the matrix by adopting a low-concentration NaCl solution or spraying the surface of the seedling from the beginning of the radicle extension period of the seed to the formation of more than 2 pairs of young leaves until the seedling grows to 5cm in plant height, pouring the plant and the matrix by adopting a 1.0% NaCl solution, and testing the survival rate and the salt adaptation capacity of the seedling, as shown in figures 3 and 4.

Each induction test is specifically as follows:

(1) No salt induction treatment was performed as a control.

(2) Continuously irrigating the substrate for 2-3 times by 0.2% NaCl solution in the radicle extending period, 1 time every 10 days, and not treating in the young leaf forming period.

(3) The radicle elongation stage and young leaf formation stage were continuously irrigated with 0.2% NaCl solution 4 times, 1 time every 10 days.

(4) The radicle extending period and the young leaf forming period are respectively irrigated with 0.2% NaCl solution and sprayed with the seedling for 2 times every 7-10 days, and 1 time is needed.

(5) The radicle is not treated in the extending period, and young leaves are continuously sprayed with 0.2% NaCl solution for 2-3 times in the forming period, and 1 time every 7 days.

(6) The cotyledon emergence period and young leaf formation period were continuously sprayed with 0.2% NaCl solution 4 times, 1 time every 7 days.

The survival rate and salt tolerance statistics of each treatment for 36 rooting seedlings per test are shown in Table 3.

TABLE 3 survival rate and salt tolerance statistics of each salt tolerance induction treatment

Note that: the survival rate is more than or equal to 80 percent, the salt adaptation capability is strong, the survival rate is less than or equal to 60 percent, the salt adaptation capability is moderate, and the survival rate is less than 60 percent, the salt adaptation capability is weak.

As shown in the statistics of Table 3, the influence of different induction treatments on the survival rate of seedlings is different, and compared with the non-induction treatment, the survival rate of plants can be improved by adopting a low-concentration NaCl solution to irrigate the matrix or spraying the surface of the seedlings. The pairwise comparison of treatments 2 with 3, 5 and 6 shows that increasing the number of induction increases the survival rate of the plants, and the watering of the substrate stimulates the salt tolerance of the seedlings and increases the survival rate more than spraying the seedlings. As the survival rate is positively correlated with the salt adapting capability, the survival rate of respectively irrigating the substrate and spraying the seedling for 2 times by adopting 0.2 percent NaCl solution is highest and reaches 91.7 percent, the salt adapting capability is considered to be strongest, and the effect of salt adapting induction treatment is best.

Example 3 ecological restoration planting and restoration Effect evaluation of coastal saline-alkali soil

In the embodiment, a repair planting test of 3 coastal saline-alkali lands is performed in a new area of a coastal bay of Dongguan city, and the specific test is implemented as follows:

1. soil sampling detection and analysis of saline-alkali soil

(1) Introduction of site to be repaired

The repairing test of the invention is positioned in a new area of a coastal bay of Dongguan city, the total area of three plots of A, B, C is 79.32 square meters, the average elevation of the plots is 3-4m, wherein the A plot is relatively higher, the elevation of the highest position is 8m, the C plot is lowest, the average elevation is about 2m, and the repairing test is of the coastal saline-alkali soil type.

(2) Soil sample collection and detection

Dividing the field into cells to be repaired according to each 667 square meter according to the field planning total plan; and (3) sampling and detecting the soil EC value of the key area by adopting a soil EC tester, and screening out a plurality of connected cells which have obvious salinization characteristics on the A, B, C three plots and are convenient to carry out planting and repairing tests. Soil EC value detection is again performed on the cells to be repaired on the A, B, C plot, as shown in fig. 5. 25 measurement points of each cell; and aiming at the point where the EC value exceeds 3.0 (mS/cm), respectively arranging soil sample collection, wherein the soil sample collection is 12 parts in total for 3 cells connected with the land block A, the soil sample collection is 16 parts in total for 4 cells connected with the land block B, and the soil sample collection is 14 parts in total for 3 cells connected with the land block C.

The soil sample total salt content detection results of the cells to be repaired of each land block are as follows, and soil salinity grades are divided according to the landscaping soil salinity grades in table 4:

the total salt content range of 12 parts of soil samples of 3 plots of the A land is 1.398-2.450 per mill, the total salt average value is 1.896 per mill, and the soil samples are classified according to the salt content grades of landscaping soil and belong to mild-moderate saline-alkali soil.

The total salt content range of 16 parts of soil samples in the 4-plot area of the B land is 1.160-2.900 per mill, the average value of the total salt is 1.685 per mill, and the soil samples are classified according to the salt content grades of landscaping soil, and the soil samples belong to mild-moderate saline-alkali soil.

The total salt content range of 14 parts of soil samples in 3 plots of the C land is 1.315-4.810 per mill, the total salt average value is 2.267 per mill, and the soil samples are classified according to the salt content grades of landscaping soil and belong to slight-severe saline-alkali soil.

Table 4 salt content rating of landscaping soil

(3) Repair policy analysis

According to detection analysis, the soil of the to-be-repaired test site comprises slight, moderate and severe salinization types, wherein the to-be-repaired area of the A, B land block belongs to slight moderate salinization, the whole to-be-repaired area of the C land block belongs to moderate and severe salinization, and the whole saline-alkali degree of the to-be-repaired area exceeds the salt content of normal landscaping soil, so that the landscaping construction in future is not facilitated. The highest salt content of the test site to be repaired is 4.810 per mill which is far lower than the lower limit value of 10.0 per mill of the salt tolerance of the screened high-salt-tolerance single-leaf fructus viticis, so that all the cells to be repaired of the A, B, C land are directly subjected to ecological planting and repairing by adopting the single-leaf fructus viticis.

2. High-salt-tolerance single-leaf fructus viticis repairing and planting method

(1) And (3) field arrangement: at the beginning of month 2 in 2020, soil in each repair district of A, B, C plots is ploughed, raked and a drain is made, as shown in fig. 6. In order to avoid the influence of artificial measures on the total salt content of the field, the district to be repaired is not subjected to fertilization treatment and soil improvement.

(2) Planting density: and in the late 2 months, 1-year-old seedling of high-salt-tolerance single-leaf fructus viticis is selected for repair planting, the initial planting density is 9 plants/m < 2 >, the seedling is placed into a dug planting hole after cup removal, original soil is backfilled, and root setting water is poured thoroughly.

(3) Root promotion by layering: in the middle and late 3 months, the main stem of the single leaf fructus viticis is pressed downwards between plant row spacing near the ground and fixed by U-shaped ground nails, so that the main stem creeping along the ground. The creeping stem sections cut off phloem of 1-3 cm at intervals of 20-25 cm at the lower part of the stem node by a sharp knife, and after the cut surface is naturally aired for 5min, the stem node is covered with 20% of hygrophilous river sand to 3-5 cm in height. After 2-3 weeks, a large number of adventitious roots are generated at the creeping stems buried in sand, as shown in fig. 7.

(4) Watering and fertilizing: at the initial stage of field planting, soil is dried for a long time, artificial watering is carried out for 1 time, natural precipitation is adopted in rainy season, and watering is not carried out in other periods. Spraying 0.005% brassin plus 1.0% urea compound aqueous solution fertilizer on leaf surfaces for 2 times at the end of 3 months and at the end of 4 months respectively; and respectively spraying 1.5% calcium superphosphate water solution fertilizer on leaf surfaces for 3 times at the beginning of 6 months and at the end of 7 months and at the end of 8 months.

(5) Repair cycle: 5-6 months, the straight root system of the single leaf tendril Jing Shi is obviously stretched to the underground, the depth of the main root system is generally more than 40cm, meanwhile, the dense adventitious roots at the creeping stem nodes are also quickly covered with a shallow soil layer of 0-40 cm, and the straight root system and the fibrous root system absorb soluble salt ions such as sodium, potassium, magnesium and the like in the soil together and are enriched in plants. After the leaves fall completely in 2 months of 2021, the plants are picked and dug, and the soil repaired by each cell is sampled again and full salt is detected.

3. Repair effect evaluation

And calculating the desalination rate of each restoration cell according to the reduction value of the total salt content in the soil before and after restoration, and evaluating the restoration effect. The statistics of the restoration and desalination effects of each plot are shown in table 5.

TABLE 5 statistics of restoration effect of soil for each plot

As shown in Table 5, the saline-alkali soil in each land planting and repairing area has a good desalting effect, the total salt reduction value ranges from 0.341 to 0.469 per mill, and the average value is 0.409 per mill; the desalination rate is 20.24% -22.05%, and the average value is 20.93%. Wherein, the most reduced value of the total salt content is C land block with the highest salt content, and the least reduced value is B land block with the lowest average salt content, which shows that the fructus viticis alone has strong salt adapting capability and desalting effect. According to the desalination effect, the A, B land block can reach the normal salt content of 1%of landscaping soil after being restored for 1 year, and the salt content of soil can be reduced to below 1%after being restored for 2 years.

Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. The method for repairing the coastal saline-alkali field is characterized by comprising the following steps of:

(1) Field arrangement and improvement: ploughing and raking up the field;

(4) Watering and fertilizing;

(5) Repairing a saline-alkali field;

(6) Post-treatment of plants: after the site repair is finished, the whole plant is excavated and uniformly recovered; the breeding method of the seedlings of the high-salt-tolerance single-leaf fructus viticis comprises the following steps:

a. seed pretreatment: soaking the seeds in clear water for 1-2 h, removing gray brown calyx and fuzz on the surfaces of the seeds, soaking the seeds in 0.2% potassium permanganate solution for 10min, washing the seeds with clear water for 2-3 times, and draining water;

b. seed germination accelerating treatment: soaking seeds 3-h in 5% acetic acid solution, soaking the seeds for 1-3 h in 2.5% acetic acid solution, taking out the seeds, cleaning, and continuously soaking the seeds in 50mg/L GA3 solution for 12-h;

c. plug seedling: sowing and raising seedlings by adopting a 72-hole tray, wherein a sowing matrix is pure vermiculite with the grain diameter of 1-2 mm or special nutrient soil for sowing, 2 seeds are sown in each hole, and 1500 times carbendazim solution is used for thoroughly watering after sowing;

d. seedling salinization induction: after sowing for 2 weeks, pouring NaCl solution with the concentration of 0.2% into the matrix, pouring for 2 times continuously every 10 days, and uniformly spraying NaCl mist aqueous solution with the concentration of 0.2% onto the surfaces of the seedlings for 1 time every 7 days when more than 2 pairs of young leaves are formed, wherein the spraying is continuously performed for 2 times;

e. transplanting seedlings: subpackaging a transplanting matrix into a nutrition cup, transplanting seedlings in a plug into the nutrition cup, and then thoroughly watering a fixed root with 800-1000 times carbendazim solution; the transplanting matrix is formed by mixing garden soil, peat soil, sea sand and farmyard manure in a volume ratio of 4:2:3:1, wherein the salt content of the sea sand is less than 3%;

f. and (3) strong seedling cultivation: after field planting for 2 weeks, spraying 9.0-15.0 g/L N every 20-30 days in the vigorous growth period in spring and summer: p: k=23: 11:14, wherein the composite water solution fertilizer is continuously sprayed for 3-6 times; 10 days before seedling, irrigating or spraying 0.2% NaCl solution on the root or leaf surface of the plant for 1-2 times to obtain strong single leaf vine Jing Shi seedling with high salt tolerance;

g. nursery stock is transplanted;

the field arrangement and improvement in the step (1) also comprises the following steps of every 667m ² Applying 40-60 kg of nitro compound fertilizer to the field of the soil, and applying the nitro compound fertilizer to the strong alkaline soil with the pH value of more than 8.5, wherein each 667m ² Sprinkling 500L of 0.02-0.04% humic acid solution;

in the step (3), the creeping stem segments are cut off phloem of 1-3 cm at intervals of 20-30 cm at the downward positions of the stem nodes, then the stem nodes are covered with wet element river sand with 20% of water content, and the height of the covered sand is 3-5 cm;

the seed source screening method of the high salt tolerance fructus viticis single leaf comprises the following steps:

1) Selection of panelists: selecting sand, sheet or strip distribution near sea and area over 50m ² The wild species group of the vitex agnus-castus is a investigation object;

2) Screening of candidate single strains: selecting robust plants with luxuriant branches and leaves as candidate single plants in a survey object;

3) Screening of target single plants: selecting a candidate single plant with the soil EC value exceeding 18 mS/cm within the root 20cm range as a target single plant;

4) Screening of excellent seed sources with high salt tolerance: selecting a target single plant with the soil total salt content of more than 1.0%, and taking the excellent single plant as a circle center, wherein plants with the radius of 4-8 m are excellent seed sources of the single-leaf fructus viticis with high salt tolerance.

2. The method for repairing a coastal saline-alkali soil according to claim 1, wherein the distance between wild species of chaste tree leaves is more than 5km, and the distance between each candidate single plant is more than 20 m.

3. Use of the method for repairing a coastal saline-alkali field as claimed in any one of claims 1 to 2 in the repair of a coastal saline-alkali field.