阅读说明：本技术 一种盐沼湿地柽柳群落土壤改良方法 (Method for improving tamarix chinensis community soil of salt marsh wetland ) 是由 孙乾照 赵超凡 孙涛 杨薇 舒安平 刘海飞 于 2020-12-03 设计创作，主要内容包括：本发明涉及盐碱化地区造林技术领域,提供了一种盐沼湿地柽柳群落土壤改良方法,包括以下步骤：挖柽柳树穴,在树穴底部铺设隔盐层,将土壤改良剂与原位土混合进行回填,回填后铺设地表覆盖材料抑制土壤水分蒸发。利用隔盐层阻断土壤毛细管力,断隔盐分上升渠道；同时结合表层覆盖措施减少土壤水分蒸散,抑制土壤返盐；并进行土壤改良,提高退化区土壤赋存能力,形成“下层隔盐,中层土壤改良防流失,上层减蒸散”的综合技术配套措施,增强盐沼湿地柽柳的抗盐碱胁迫能力,提升柽柳幼苗移栽成活率。(The invention relates to the technical field of afforestation in salinized areas, and provides a method for improving tamarix chinensis community soil in a salinized marsh wetland, which comprises the following steps: digging a tamarix chinensis pit, paving a salt isolation layer at the bottom of the pit, mixing the soil conditioner and the in-situ soil for backfilling, and paving a ground surface covering material for inhibiting the evaporation of soil moisture after backfilling. Blocking the capillary force of soil by using a salt isolation layer, and isolating a salt ascending channel; meanwhile, the soil moisture evaporation is reduced by combining a surface covering measure, and the soil salt return is inhibited; and improving soil, improving the survival capacity of the soil in the degradation area, forming a comprehensive technical matching measure of 'salt isolation at the lower layer, soil improvement at the middle layer for preventing loss and evaporation at the upper layer', enhancing the saline-alkali stress resistance of the tamarix chinensis in the saline marsh wetland, and improving the transplanting survival rate of the tamarix chinensis seedlings.)

1. A method for improving tamarix chinensis community soil of a saline marsh wetland is characterized by comprising the steps of digging a tamarix chinensis pit, paving a salt isolation layer at the bottom of the pit, mixing a soil conditioner and in-situ soil for backfilling, and paving a ground surface covering material for inhibiting soil moisture evaporation after backfilling.

2. The improvement of claim 1, wherein the salt barrier material is one or more of river sand, slag, vermiculite, ceramsite and plant straw.

3. The improved method of claim 1, wherein the top of the salt barrier is 25-35 cm from the earth's surface and the thickness of the salt barrier is 15-25 cm.

4. The improvement method according to claim 1, wherein the soil conditioner is attapulgite and/or zeolite.

5. The improvement method according to claim 1, wherein the volume ratio of the soil conditioner to the in-situ soil is 1: 2-4.

6. The improvement method according to claim 1, wherein the grain size of the soil conditioner is 10 to 200 mesh.

7. The improvement method according to claim 1, wherein after the salt-separating layer is laid, and before the soil conditioner and the in-situ soil are backfilled, ammonium nitrogen fertilizer is applied to the tree pit.

8. The improved method of claim 1, wherein the surface covering material is one of plastic greenhouse film, sand, and plant straw.

9. The improvement according to claim 2 or 8, wherein the plant straw is a grass straw.

10. The improvement as claimed in claim 8, wherein the thickness of the plastic greenhouse film is 0.01mm or more; the covering thickness of the sandy soil is 4-6 cm; the covering thickness of the plant straws is 5-10 cm.

Technical Field

The invention belongs to the technical field of afforestation in salinized areas, and particularly relates to a method for improving tamarix chinensis community soil in a saline marsh wetland.

Background

The coastal degraded wetland has the advantages that the living environment of plants is severe, shallow underground water is buried deeply, strong soil moisture evaporation and diffusion and strong salt accumulation activities enable the salinity of the surface layer of the soil to be high, and the recovery of coastal vegetation communities is limited. At present, there are few reports on successful recovery cases of severely degraded areas of the maritime tamarix chinensis community. The previous ecological restoration measures for salinization areas of coastal wetlands mainly take engineering measures for reducing the salinity of soil and reducing the external salinization stress of plant communities, pay attention to the enhancement of the salinization stress resistance in plant bodies, and have less restoration research on degraded areas adapted to the environment.

Tamarix chinensis belongs to Tamaricaceae, genus Tamarix, and is a shrub or small tree. A large number of researches show that the tamarix chinensis has strong saline-alkali tolerance, and the tolerance of mature tamarix chinensis plants to soil salinity can reach more than 10ppt in a field environment. The tamarix chinensis is suitable for growing in harsh environments such as desert, saline-alkali desert and coastal saline-alkali wetland, and plays an irreplaceable role in aspects of preventing wind and fixing sand, conserving water sources, increasing biological diversity of the wetland, improving coastal ecological environment and the like. Although the tamarix chinensis has certain salt tolerance, a large amount of salt-tolerant plants (limonium sinense, cogongrass rhizome and the like) die due to the fact that soil salinization is too serious, and the increase of soluble salt and unbalanced distribution of soil nutrients, in the previous research, the tamarix chinensis is transplanted in a saline marsh wetland from 4 months to the beginning, the transplanting survival rate is less than 30% in 5 months, the transplanting survival rate is 0% in 6-10 months, and all the plants die. How to improve the saline marsh wetland soil, improve the inorganic nitrogen occurrence capacity of the saline marsh wetland soil, enhance the saline-alkali stress resistance of the tamarix chinensis seedlings and restore tamarix chinensis vegetation communities in the saline marsh wetland on a large scale is a problem which needs to be solved at present.

Disclosure of Invention

In view of the above, the present invention provides a method for improving tamarix chinensis community soil in a saline marsh wetland, which improves the soil in the saline marsh wetland and enhances the inorganic nitrogen occurrence capacity of the soil in the saline marsh wetland, so as to enhance the saline-alkali stress resistance of tamarix chinensis and enhance the transplanting survival rate.

In order to achieve the above purpose, the invention provides the following technical scheme:

a method for improving the tamarix chinensis community soil of a saline marsh wetland comprises the steps of digging a tamarix chinensis pit, paving a salt isolation layer at the bottom of the pit, mixing a soil conditioner and in-situ soil for backfilling, and paving a ground surface covering material for inhibiting the evaporation of soil water after backfilling.

Preferably, the salt isolation layer material is one or more of river sand, furnace slag, vermiculite, ceramsite and plant straws; more preferably, the salt isolation layer material is one or a mixture of plant straws and river sand, furnace slag, vermiculite and ceramsite.

Preferably, the top of the salt isolation layer is 25-35 cm away from the ground surface, and the thickness of the salt isolation layer is 15-25 cm.

Preferably, the soil conditioner is attapulgite and/or zeolite.

Preferably, the volume ratio of the soil conditioner to the in-situ soil is 1: 2-4.

Preferably, the particle size of the soil conditioner is 10-200 meshes.

Preferably, after the salt isolation layer is laid, and before the soil conditioner and the in-situ soil are backfilled, an ammonium nitrogen fertilizer is applied to the tree pits.

Preferably, the ground surface covering material is one of plastic greenhouse film, sandy soil and plant straws.

More preferably, the plant straw is a grass straw.

More preferably, the thickness of the plastic greenhouse film is more than 0.01 mm; the covering thickness of the sandy soil is 4-6 cm; the covering thickness of the plant straws is 5-10 cm.

Compared with the prior art, the invention has the following beneficial effects:

test results of two saline-alkali treatment technologies of surface covering treatment and salt barrier technology show that the effect of salt inhibition of the surface covering technology is very obvious, and the effect of the salt barrier on reducing the salt content of soil is obvious. The two technologies can better reduce the external saline-alkali stress of the tamarix chinensis seedlings on the saline marsh wetland and are beneficial to the survival of the tamarix chinensis seedlings.

The soil conditioner can improve the nutrient condition of nitrogen element in soil and effectively improve the survival rate of tamarix chinensis seedlings. The method can further improve the soil texture, effectively improve the inorganic nitrogen occurrence capacity of the soil, and more effectively promote the survival and growth of the tamarix chinensis. The soil improvement technology has obvious effect on the survival and plant growth of the tamarix chinensis seedlings.

The invention provides a comprehensive technical matching measure of 'salt isolation at the lower layer, soil improvement and loss prevention at the middle layer and evapotranspiration reduction at the upper layer', which can be used for: 1) the accumulation of salt on the surface layer of the soil is inhibited, and the salinity of the soil is obviously reduced; 2) obviously improving and improving the occurrence capacity of the soil ammonium nitrogen; 3) the survival rate and the growth condition of the tamarix chinensis seedlings are effectively improved; 4) effectively enhancing the biochemical response of the tamarix chinensis seedlings in the severe saline-alkali stress environment. The effect of the 'good isolation and reduction' combination on improvement of the external environment of the tamarix chinensis living soil environment and enhancement of the environment adaptive capacity of the tamarix chinensis is very obvious.

Drawings

FIG. 1: the invention discloses a schematic diagram of a method for improving tamarix chinensis community soil in a salt marsh wetland;

FIG. 2: influence of salt barrier treatment on saline-alkali soil salinity;

FIG. 3: influence of salt-separating layer treatment on the water content of saline-alkali soil;

FIG. 4: influence of salt separation layer treatment on the salt reduction rate of saline-alkali soil;

FIG. 5: the salt separation layer is used for treating influences on SOD and POD activity conditions and MDA content of tamarix chinensis seedlings in the saline-alkali soil;

FIG. 6: influence of the soil conditioner on the saline-alkali soil salinity;

FIG. 7: influence of the soil conditioner on the water content of the saline-alkali soil;

FIG. 8: the influence of the soil conditioner on the contents of ammonium nitrogen and nitrate nitrogen in the saline-alkali soil;

FIG. 9: the influence of the soil conditioner on the SOD and POD activity conditions and the MDA content of the tamarix chinensis seedlings on the saline-alkali soil;

FIG. 10: the influence of different mixing proportions of the soil conditioner and the in-situ soil on the soil salinity of the saline-alkali soil;

FIG. 11: the influence of different mixing ratios of the soil conditioner and the in-situ soil on the water content of the saline-alkali soil;

FIG. 12: the influence of different mixing proportions of the soil conditioner and the in-situ soil on the contents of ammonium nitrogen and nitrate nitrogen in the saline-alkali soil;

FIG. 13: the influence of different mixing proportions of the soil conditioner and the in-situ soil on the activity conditions of SOD and POD of the tamarix chinensis seedlings and the content of MDA;

FIG. 14: the influence of the soil conditioners with different grain sizes on the saline-alkali soil salinity is avoided;

FIG. 15: the influence of soil conditioners with different particle sizes on the water content of the saline-alkali soil;

FIG. 16: the influence of the soil conditioners with different grain diameters on the contents of ammonium nitrogen and nitrate nitrogen in the saline-alkali soil;

FIG. 17: the influence of the soil conditioners with different particle sizes on the SOD and POD activity conditions and the MDA content of the tamarix chinensis seedlings;

FIG. 18: the influence of surface covering treatment on saline-alkali soil salinity is avoided;

FIG. 19: influence of surface covering treatment on the water content of saline-alkali soil;

FIG. 20: the influence of surface covering treatment on the salt reduction rate of saline-alkali soil;

FIG. 21: the surface covering treatment influences the SOD and POD activity conditions and the MDA content of the tamarix chinensis seedlings in the saline-alkali soil;

FIG. 22: influence of different optimized combinations on saline-alkali soil salinity;

FIG. 23: influence of different optimized combinations on the water content of the saline-alkali soil;

FIG. 24: influence of different optimized combinations on the salt reduction rate of the saline-alkali soil;

FIG. 25: the influence of different optimized combinations on the contents of ammonium nitrogen and nitrate nitrogen in the saline-alkali soil;

FIG. 26: influence of different optimized combinations on SOD and POD activity conditions and MDA content of tamarix chinensis seedlings in saline-alkali soil.

Detailed Description

The invention provides a method for improving tamarix chinensis community soil in a salt marsh wetland, which integrates the advantages of a salt isolation layer, soil improvement and surface coverage and simultaneously applies three measures in tamarix chinensis forestation in the salt marsh wetland. Blocking the capillary force of soil by using a salt isolation layer, and isolating a salt ascending channel; meanwhile, the soil moisture evaporation is reduced by combining a surface covering measure, and the soil salt return is inhibited; and soil improvement is carried out, the occurrence capacity of the soil in the degradation area is improved, and comprehensive technical matching measures of 'salt isolation at the lower layer, soil improvement and loss prevention at the middle layer and evapotranspiration reduction at the upper layer' are formed.

When the tamarix chinensis community soil of the salt marsh wetland is improved, the area of the pit of the tamarix chinensis cultivation tree is preferably 0.5-2 m²The pitch is 0.8 to 1.2 m.

According to the invention, the salt isolation layer can isolate the continuity of soil capillary, greatly reduce the capillary effect of soil, reduce the evapotranspiration of soil moisture, reduce the rise of salt along with moisture, and reduce the accumulation of salt on the surface layer of soil, thereby reducing the salinity of the soil surface. In the invention, the preferable salt isolation layer material is one or more of river sand, furnace slag, vermiculite, ceramsite and plant straw, the further preferable salt isolation layer material is the mixture of plant straw and one or more of river sand, furnace slag, vermiculite and ceramsite, and the more preferable plant straw is gramineous plant straw, such as reed collected from a saline marsh wetland and the like. The plant straw is used as a salt-separating layer, the plant straw is a gramineous plant, the residue of the gramineous plant is rich in nitrogen, phosphorus, potassium, calcium, magnesium, organic matters and the like, the gramineous plant is an excellent organic matter capable of providing nutrition for soil, and nutrient substances for living growth of plants can be released into the soil when the plant straw is decomposed under the action of soil microorganisms, so that the soil environment of a sample is improved, the growth and development of Chinese tamarisk seedlings are promoted, and the Chinese tamarisk seedling growth-promoting salt marsh wetland is particularly important for the survival, growth and development of the Chinese tamarisk seedlings in salt-poor marsh wetland. The straw salt barrier layer promoting the growth of the tamarix chinensis seedlings is probably caused by the decomposition of organisms, and although the possible nutrition supply of the straw salt barrier layer is helpful for the recovery and expansion of the tamarix chinensis community, the straw salt barrier layer also means that the physical property of the straw salt barrier layer serving as the salt barrier layer can be gradually weakened after the organisms are decomposed, so that the negative influence on the salt return inhibition can be caused. Therefore, the plant straws are used as the material for processing the salt-separating layer, and other materials which are not decomposed are matched, so that the long-term property and the continuity of the effect of the salt-separating layer are ensured. More preferably, the top of the salt isolation layer is 25-35 cm away from the ground surface, and the thickness of the salt isolation layer is 15-25 cm. More preferably, the top of the salt insulation layer is 30cm away from the ground surface, and the thickness of the salt insulation layer is 20 cm.

In the present invention, the soil improvement layer is formed by adding a soil improvement agent to in-situ soil. The soil improvement layer can directly promote the nutrient level of soil, can also improve soil property to the bad texture and the structure of soil, improves the occurrence ability to effective state nutrient substance, helps vegetation. The present invention prefers attapulgite and/or zeolite as a soil amendment. Further preferably, before the soil conditioner and the in-situ soil are mixed and backfilled, an ammonium nitrogen fertilizer is applied to the tree pits, and more preferably, 40-60 g of the ammonium nitrogen fertilizer is applied.

The different proportions and different particle sizes of the soil conditioner and the in-situ soil also affect the effect of the soil conditioning layer. According to the invention, the mixing ratio of the soil conditioner to the in-situ soil is preferably 1: 2-4, and more preferably 1: 2. The grain size of the soil conditioner is preferably 10-200 meshes, and the grain size of the soil conditioner is more preferably 200 meshes.

The surface covering measures can prevent the direct impact of rainfall on the soil, prevent the earth surface from crusting, inhibit the strong evaporation and diffusion of the earth surface, prevent the soil from salt return activity, effectively accumulate and dissolve the rainwater in the soil, promote rainfall eluviation and reduce the salt content of the soil. The preferable surface covering material of the invention is one of plastic greenhouse film, sandy soil and plant straw, and further preferable plant straw. More preferably, the thickness of the plastic greenhouse film is more than 0.01mm, and soil is compacted around the plastic greenhouse film; covering the sandy soil to a thickness of 4-6 cm; the covering thickness of the plant straws is 5-10 cm.

In the invention, after the comprehensive technical matching measures of 'salt isolation at the lower layer, soil improvement and loss prevention at the middle layer and evapotranspiration reduction at the upper layer' are constructed, the tamarix chinensis seedlings are transplanted. Preferably, the height of the ground seedlings of the transplanted Chinese tamarisk seedlings is more than 8cm, the ground diameter is more than 0.4cm, and the transplanting density is 15-25 plants/m². More preferably, after transplanting the seedlings, flood irrigation is carried out, and sufficient root fixing water is poured.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

A method for improving tamarix chinensis community soil of a saline marsh wetland comprises the following steps:

(1) digging a tree pit of the tamarix chinensis seedling, wherein the specification of the tree pit is 1m of the area of the sample square²And the sample space is 1 m.

(2) The material used in the salt isolation layer is plant straw and river sand which are mixed in equal volume, the bottom layer of the sample is paved with the mixture for 20cm, and the distance between the salt isolation layer and the ground surface is 30 cm. The plant straw is reed straw; the river sand has the grain size composition of 21.24% in 1mm and 18.74% in <0.1 mm.

(3) Applying ammonium sulfate ((NH) to the sample₄)₂SO₄)50g；

(4) The soil conditioner is prepared by mixing attapulgite and zeolite in an equal volume ratio, the particle size is 200 meshes, the soil conditioner and in-situ soil are uniformly mixed according to the volume ratio of 1:2, and backfilling is carried out on a sample, wherein the thickness of the conditioner is 30cm below the ground surface.

(5) And after backfilling, covering the surface layer, wherein the material used for covering the surface layer is plant straw, the plant straw is reed straw, and the thickness is 5-10 cm.

(6) After the surface coverage is finished, the density of the seedlings in each sample is 20 plants/m²And transplanting the tamarix chinensis seedlings. Selecting tamarix chinensis seedlings as container seedlings, wherein the overground seedlings are 10cm high, and the average ground diameter is 0.5 cm.

Example 2

A method for improving tamarix chinensis community soil of a saline marsh wetland comprises the following steps:

(1) digging a pit of the tamarix chinensis seedling, wherein the size of the pit is 0.5m of the area of the sample²And a spline pitch of 0.8 m.

(2) The material used in the salt isolation layer is river sand and vermiculite with equal volume, the bottom layer of the sample is paved with 25cm, and the distance between the salt isolation layer and the ground surface is 25 cm. The river sand has the grain size composition of 21.24% in 1mm and 18.74% in <0.1 mm.

(3) Applying ammonium sulfate ((NH) to the sample₄)₂SO₄)40g；

(4) The soil conditioner is attapulgite with the grain diameter of 30-120 meshes, the attapulgite and the in-situ soil are uniformly mixed according to the volume ratio of 1:3, the soil conditioner is backfilled to the sample, and the thickness of the conditioner layer is 25cm from the ground surface.

(5) And after backfilling, covering the surface layer, wherein the surface layer is made of a plastic greenhouse film, the film thickness is 0.lmm, the specification is 1.5m multiplied by 0.8m, and soil is compacted around.

(6) After the surface covering is finished, the density of seedlings in each sample is 15 plants/m²And transplanting the tamarix chinensis seedlings. Selecting tamarix chinensis seedlings as container seedlings, wherein the height of overground seedlings is 8cm, and the average ground diameter is 0.4 cm.

Example 3

A method for improving tamarix chinensis community soil of a saline marsh wetland comprises the following steps:

(1) digging a pit of the tamarix chinensis seedling, wherein the size of the pit is 2m²The pitch of the squares was 1.2 m.

(2) The salt isolation layer is made of plant straws, 15cm is paved on the bottom layer of the sample square, and the salt isolation layer is compacted, wherein the distance between the salt isolation layer and the ground surface is 35 cm. The plant straw is reed straw.

(3) Applying ammonium sulfate ((NH) to the sample₄)₂SO₄)60g；

(4) The soil conditioner is zeolite with the grain diameter of 10 meshes, the zeolite and the in-situ soil are uniformly mixed according to the volume ratio of 1:4, the soil conditioner is backfilled to the sample, and the thickness of the conditioner layer is 35cm from the ground surface.

(5) And after backfilling, covering the surface, wherein the covering material of the surface layer is sandy soil, and the covering thickness is 4-6 cm.

(6) After the surface covering is finished, the density of seedlings in each sample is 25 plants/m²And transplanting the tamarix chinensis seedlings. Selecting tamarix chinensis seedlings as container seedlings, wherein the height of overground seedlings is 12cm, and the average ground diameter is 0.6 cm.

Example 4

Influence on improvement of tamarix chinensis community soil of salt marsh wetland under different salt isolation layers

As an alternative embodiment, the salt-barrier single-treatment test is carried out by using reed and sand as the salt-barrier materials. Specifically, the method comprises the following steps: the tamarix chinensis seedlings used in the test are container seedlings, the height of overground seedlings is 10cm, and the average ground diameter is 0.5 cm. The standard of the sample is 1m × 0.5m × 0.5m, 10 seedlings are planted on each sample, and the interval between the samples is 1 m. Each salt-separating material is provided with 3 parallel processing samples. Processing one: paving 20cm of sand on the bottom layer of the sample square, wherein the sand layer is 30cm away from the ground surface, the sand material is common river sand, the grain size composition is that the sand accounts for 21.24% when the sand layer is larger than 1mm, and the grain size accounts for 18.74% when the sand layer is smaller than 0.1 mm; and (5) processing: and (3) laying the bulrush 20-25cm (compacted) on the bottom layer of the sample square, and collecting the bulrush nearby in the national wetland natural protection area of the yellow river estuary. After the salt isolation layer is laid, backfilling the original soil layer by layer and transplanting tamarix chinensis seedlings. And (3) when the tamarix chinensis seedlings are transplanted, flood irrigation is carried out on the sample, enough water is poured for root fixing, and then water is not poured again. A control group was prepared without treatment with a salt-barrier layer. The stock sample preparation and the tamarix chinensis seedling transplantation are carried out in 2017 and 4 months.

And (3) test results:

according to the graph shown in FIG. 2, the salinity of the sample square treated by the salt separation layer is lower than that of the control group without treatment, and the salinity of the sample square treated by the salt separation layer covering is changed in a smaller range in the change of the salinity of the soil in spring and autumn than that of the control group, which shows that the salt separation treatment can effectively inhibit the increase of the salinity of the soil. The salinity of the control group and the salinity of the reed and sand salt-separating layer test group are respectively 7.27ppt, 6.66ppt and 6.56ppt, and the salinity of the control group and the reed and sand salt-separating layer test group is respectively 4.42ppt, 3.24ppt and 3.38 ppt. Therefore, the salt-separating layer treatment effect is obvious in the environment of the area with the serious degeneration of the tamarix chinensis. However, as shown in fig. 3, the salt-separating layer has no great influence on the water content of the soil in the salt-separating layer single-treatment test. According to the graph shown in FIG. 4, different salt-separating layer materials have different barrier effects on the upper and lower soil layers, so that the influence of the salt-reducing rate on the soil is different, and in 8 months or before, the reed is larger than the sand; however, in 9 and 10 months of monitoring, sand > reed.

According to table 1, different salt barrier materials have different effects on the survival rate of tamarix chinensis seedlings. The survival rate of tamarix chinensis seedlings in 5 months in the control group is 26.67% by statistics, but the seedlings are not survived in 6 months. The survival rates of the tamarix chinensis seedlings in 5 months are respectively 33.33% and 36.67% in a sand and reed salt-barrier test group, and the survival rates of the seedlings are respectively reduced to 16.67% and 13.33% in 6 months. From the physiological perspective of tamarix chinensis life, the effect of the two salt barrier layer treatments on the life of tamarix chinensis seedlings is considered, as can be seen from table 2, the plant height and the crown width of the tamarix chinensis seedlings under the sand and reed salt barrier treatment are respectively 26.26cm, 24.63cm, 15.86cm and 14.43cm, the life condition under the reed salt barrier treatment is the best, and the plant height and the crown width of the tamarix chinensis seedlings are respectively the highest in view of the growth of the tamarix chinensis plant height and the crown width.

Table 1: survival rate of tamarix chinensis seedlings under different salt barrier materials

Table 2: physiological conditions of tamarix chinensis seedlings under different salt barrier materials

From the biochemical perspective of the tamarix chinensis seedlings, the effect of two salt-separating treatments on the life of the tamarix chinensis seedlings is examined, as shown in fig. 5, the SOD and POD of the tamarix chinensis seedling leaves under the reed and sand salt-separating layer treatment are 169.06 mu/g.FW, 168.82 mu/g.FW, 285.82 mu/g.FW and 288.93 mu/g.FW respectively, and the MDA is 21.35umol/g and 21.73umol/g respectively. The SOD activity and POD activity conditions of the leaves of the tamarix chinensis plantlets treated by the two salt isolation layers are not different, and the MDA test data are not greatly different. The biochemical condition of tamarix chinensis survived for 6 months under the two salt-separating layer treatments is shown, and no obvious difference exists between the two treatments.

Example 5

Influence of different soil conditioner treatments on tamarix chinensis community soil improvement of salt marsh wetland

As an optional implementation mode, attapulgite with the grain size of 30-120 meshes and zeolite are respectively used as soil conditioners and are mixed with in-situ soil according to the volume ratio of 1:3, and a soil improvement layer single treatment test is carried out. The method specifically comprises the following steps: the tamarix chinensis seedlings used in the test are container seedlings, the height of overground seedlings is 10cm, and the average ground diameter is 0.5 cm. The standard of the sample is 1m × 0.5m × 0.5m, 10 seedlings are planted on each sample, and the interval between the samples is 1 m. Each test treatment was set with 3 parallel treatment squares. The depth of the soil improvement layer in the test is 30cm from the ground surface, and after the soil is filled into a sample by 20cm, the soil improvement layer is appliedAmmonium sulfate ((NH)₄)₂SO₄)50g, then laying a sample according to the test design, mixing the required materials, proportion and particle size with the in-situ soil phase respectively, and backfilling. And after the soil improvement layer is laid, transplanting the tamarix chinensis seedlings. And (3) when the tamarix chinensis seedlings are transplanted, flood irrigation is carried out on the sample, enough water is poured for root fixing, and then water is not poured again. Separately, 30cm from the surface of the earth, ammonium sulfate ((NH) was applied₄)₂SO₄) And after 50g, backfilling a group of nitrogen application reference samples of the in-situ soil according to layers.

And (3) test results:

according to the graph shown in FIG. 6, the salinity of the control group, the attapulgite and the zeolite treatment group is 7.33ppt, 6.84ppt and 7.01ppt respectively at 6 months; the salinity of the 7-month control group, the salinity of the attapulgite and the salinity of the zeolite-treated group were 4.52ppt, 4.10ppt and 4.37ppt, respectively. The salinity of the attapulgite improving sample is obviously lower than that of the soil of the control group, and the salinity of the soil sample of the attapulgite improving sample is increased by a range lower than that of the sample of the control group in the soil salt return period and the salt return period; in the salt reducing period, the soil salinity is smaller than that of a control group, and the obvious inhibiting effect on the soil salinity is shown. The zeolite-modified sample can also inhibit the increase of soil salinity under strong soil moisture evaporation, but the effect is not significant. According to FIG. 7, the soil moisture content of the test sample and the control group was at a minimum in 6 months and peaked in 7 months. Wherein, in 6 months, the water content of the control group is 15.36 percent, and the soil water content of the attapulgite and zeolite soil improvement test group is 17.32 percent and 17.34 percent respectively; and 7 months later, the water content of the control group is 21.49%, and the soil water content of the attapulgite and the zeolite improvement test group respectively reaches 22.83% and 23.36%. The water content of the test group is obviously larger than that of the control group. As shown in figure 8, the soil conditioner also has influence on the content of ammonium nitrogen in the saline-alkali soil, the soil conditioning sample prescription of the attapulgite and the zeolite is obviously larger than that of a control group, and the time is considered, namely, 8 months is longer than 10 months and longer than 6 months. In the test, the ammonium nitrogen content of the control group, the attapulgite and the zeolite modified group is 5.67mg/kg, 9.42mg/kg and 8.56mg/kg respectively in 6 months which are relatively the lowest; the soil has the highest content of ammonium nitrogen for 8 months, and the contents of the ammonium nitrogen in the soil are respectively 8.36mg/kg, 15.48mg/kg and 17.44 mg/kg. The time sequence of the content of the nitrate nitrogen in the soil is the same as that of the ammonium nitrogen, wherein the content of the nitrate nitrogen is the lowest in 6 months, and the content of the nitrate nitrogen in the control group, the attapulgite and the zeolite improvement group is 0.13mg/kg, 0.14mg/kg and 0.11mg/kg respectively; the content of nitrate nitrogen in the soil is 0.50mg/kg, 0.71mg/kg and 0.78mg/kg respectively in the highest 8 months.

According to table 3, the survival rates of tamarix chinensis seedlings under soil improvement of different materials are different. The survival rate of the tamarix chinensis seedlings in the soil improvement test in 5 months is 40.00 percent, but the survival rate in 6 months is 16.67 percent. In the attapulgite and zeolite soil improvement test group, the survival rates of the tamarix chinensis seedlings in 5 months are respectively 43.33 percent and 46.67 percent, and the survival rates of the seedlings are respectively reduced to 26.67 percent and 23.33 percent when the statistics of 6-10 months are carried out. From the physiological perspective of tamarix chinensis life, the effect of different soil conditioners on the life of tamarix chinensis seedlings was examined, and as can be seen from table 4, the plant heights and the crown widths of the tamarix chinensis seedlings under the soil improvement treatment of the control group, the attapulgite and the zeolite were 30.63cm, 43.50cm, 41.79cm, 17.54cm, 20.10cm and 19.77cm, respectively. The physiological status of the tamarix chinensis seedlings of the attapulgite and zeolite soil improvement group is superior to the life status of the control group, which is related to the improvement group being capable of providing more macroelement nitrogen in the life history of the tamarix chinensis seedlings.

Table 3: survival rate of tamarix chinensis seedlings under different soil improvement layers

Table 4: physiological conditions of Tamarix chinensis seedlings under different soil improvement layers

As shown in FIG. 9, the SOD and POD of the leaves of Tamarix chinensis seedlings treated with control group, attapulgite and zeolite soil improvement were 201.95 μ/g.FW, 212.09 μ/g.FW, 213.44 μ/g.FW, 325.62 μ/g.FW, 345.01 μ/g.FW and 343.48 μ/g.FW, respectively, and the MDA was 20.48, 18.65 and 18.78umol/g, respectively. Therefore, the improved sample formulation with more ammonium nitrogen exists, and the tamarix chinensis seedlings can generate more SOD and POD physiologically to reduce the oxidation reaction caused by saline-alkali stress and reduce the damage to cell membranes.

Example 6

Influence of different mixing proportions of the soil conditioner and the in-situ soil on soil improvement of tamarix chinensis communities of saline marsh wetland

As an alternative embodiment, the soil improvement layer single treatment tests with different mixing ratios are carried out by taking attapulgite as the soil improvement agent. Specifically, the method comprises the following steps: the design is the same as that of the sample in the embodiment 5, except that the attapulgite and the in-situ soil are mixed according to different proportions, and the volume mixing proportion of the attapulgite and the in-situ soil is respectively 1:2, 1:3 and 1: 4.

And (3) test results:

as shown in FIG. 10, the salinity of the control group, the attapulgite mixing ratio of 1:2, the attapulgite mixing ratio of 1:3 and the attapulgite mixing ratio of 1:4 were 7.33ppt, 6.74ppt, 6.84ppt and 7.13ppt, respectively, at 6 months; the four 7-month salt fractions were 4.52ppt, 4.14ppt, 4.10ppt, 4.22ppt, respectively. It can be seen that, at high salinity, the salinity of the attapulgite clay improving group is obviously lower than that of the control group sample formula, and the effect of the attapulgite clay for inhibiting the salt increase in the soil sample formula improvement is more obvious along with the increase of the adding proportion of the attapulgite clay. According to fig. 11, the water content of the soil of each group is at a minimum in 6 months and reaches a maximum in 7 months. The soil moisture content of the sample is closely related to the precipitation and the water evapotranspiration effect of the soil sample. For 6 months, the water content of the control group is 15.36%, the soil water content of the test group with the concave soil mixing ratio of 1:2, the concave soil mixing ratio of 1:3 and the concave soil mixing ratio of 1:4 is 17.70%, 17.32% and 16.56% respectively; and 7 months later, the water content of the control group is 21.49%, and the soil water content of the control group, the attapulgite mixing ratio of 1:2, the attapulgite mixing ratio of 1:3 and the attapulgite mixing ratio of 1:4 respectively reach 23.29%, 22.83% and 22.34%. Due to the water absorption and water retention of the attapulgite clay, the water content of the test group is obviously greater than that of the control group, and the soil water content is increased along with the increase of the feeding amount of the attapulgite. According to FIG. 12, the content of ammonium nitrogen in soil, the sample formulation of the attapulgite modification treatment is significantly larger than that of the control group; from a time perspective, 8 months > 10 months > 6 months. Wherein, in the test for 6 months at the lowest, the ammonium nitrogen contents of a control group, an attapulgite mixing ratio of 1:2, an attapulgite mixing ratio of 1:3 and an attapulgite mixing ratio of 1:4 are respectively 5.67mg/kg, 11.47mg/kg, 9.42mg/kg and 8.43 mg/kg; the soil has the highest content of ammonium nitrogen for 8 months, and the content of the ammonium nitrogen in the soil is respectively 8.36mg/kg, 17.15mg/kg, 15.47mg/kg and 14.42 mg/kg. The time sequence of the content of the nitrate nitrogen in the soil is the same as that of the ammonium nitrogen, wherein the content of the nitrate nitrogen is the lowest in 6 months, and the content of the nitrate nitrogen in the control group is respectively 0.13mg/kg, 0.19mg/kg, 0.14mg/kg and 0.15mg/kg in the attapulgite mixing ratio of 1:2, the attapulgite mixing ratio of 1:3 and the attapulgite mixing ratio of 1: 4; the content of nitrate nitrogen in soil is 0.50mg/kg, 0.83mg/kg, 0.71mg/kg and 0.82mg/kg respectively in the four plants with the highest month of 8.

As shown in Table 5, the survival rates of Tamarix chinensis seedlings under soil improvement were different at different mixing ratios. The survival rate of the tamarix chinensis seedlings in the soil improvement test in 5 months is 40.00 percent, but the survival rate in 6 months is 16.67 percent. The mixing ratio of the attapulgite to the attapulgite is 1:2, the mixing ratio of the attapulgite to the attapulgite is 1:3, the mixing ratio of the attapulgite to the attapulgite is 1:4, the survival rates of the tamarix chinensis seedlings in 5 months are 46.67%, 43.33% and 46.67% respectively, and the survival rates of the seedlings are 23.33%, 26.673% and 20.00% respectively when counted in 6-10 months. The attapulgite mixed improved sample prescription is obviously higher than that of a control group. From the physiological perspective of tamarix chinensis life, the effect of soil improvement on tamarix chinensis seedling life at different attapulgite soil mixing ratios was examined, and as can be seen from table 6, the plant height and crown width of tamarix chinensis seedlings treated by the control group, the 1:2 sample attapulgite soil mixing ratio, the 1:3 sample attapulgite soil mixing ratio and the 1:4 sample attapulgite soil mixing ratio were 30.63cm, 44.08cm, 43.50cm, 42.47cm and 17.54cm, 21.31cm, 20.10cm and 20.63cm, respectively. The physiological conditions of the tamarix chinensis seedlings of the test groups which are added with the attapulgite rods in different proportions for soil improvement are far greater than those of the tamarix chinensis seedlings of the control groups, which is related to that the improved groups can provide more macroelement nitrogen in the life history of the tamarix chinensis seedlings.

Table 5: survival rate of tamarix chinensis seedlings under different mixing proportions of soil improvement layer

Table 6: physiological conditions of tamarix chinensis seedlings under different mixing proportions of soil improvement layer

From the biochemical perspective of tamarix chinensis seedlings, the effect of soil improvement of different mixing ratios on tamarix chinensis seedling life was examined, and as can be seen from fig. 13, the SOD and POD of tamarix chinensis seedling leaves under the soil improvement treatment of the control group, the 1:2 sample formula of attapulgite, the 1:3 sample formula of attapulgite and the 1:4 sample formula of attapulgite were 201.95 μ/g.fw, 222.39 μ/g.fw, 212.09 μ/g.fw, 213.29 μ/g.fw, 325.62 μ/g.fw, 360.06 μ/g.fw, 345.01 μ/g.fw and 333.92 μ/g.fw, respectively, and the MDA were 20.48umol/g, 17.98umol/g, 18.63umol/g and 18.99umol/g, respectively. SOD and POD of tamarix chinensis seedlings in the improved sample prescription are obviously higher than those in the control sample prescription, and the opposite is true for MDA. This is because the more ammonium nitrogen is available in the living environment, the more SOD and POD are produced by Tamarix chinensis seedlings, and the less damage to cell membranes is caused. The results also show that the larger the amount of attapulgite added, the higher the SOD and POD, and vice versa.

Example 7

Influence of soil conditioners with different particle sizes on improvement of tamarix chinensis community soil of saline marsh wetland

As an alternative embodiment, the soil improvement layer single-treatment test of the soil improvement agent with different particle sizes is carried out by taking attapulgite as the soil improvement agent. Specifically, the method comprises the following steps: the test was conducted using 10 to 30 mesh, 30 to 120 mesh and 200 mesh attapulgite, respectively, in the same design as in example 5 except that the particle size of the attapulgite was different.

And (3) test results:

according to FIG. 14, the salinity of the control group, the attapulgite particle size 10-30 mesh, the attapulgite particle size 30-120 mesh and the attapulgite particle size 200 mesh modified group were 7.33ppt, 7.03ppt, 6.84ppt and 6.91ppt, respectively, at 6 months; the salt contents of the control group at 7 months, the particle size of the attapulgite clay is 10-30 meshes, the particle size of the attapulgite clay is 30-120 meshes, and the salt contents of the modified group with the particle size of the attapulgite clay of 200 meshes are 4.52ppt, 4.26ppt, 4.10ppt and 4.08ppt respectively. Therefore, the smaller the grain size of the added attapulgite is, the smaller the salinity of the sample is relatively. This is because, in the case of the same mixing ratio, the smaller the particle size, the more the physical contact between the attapulgite is, the stronger the effect of blocking soil moisture transpiration is, and the more remarkable the effect of inhibiting the accumulation of salt on the surface layer of the soil is. As shown in fig. 15, the water content of each of the particle size test group and the control group reached the maximum value at 7 months. For 6 months, the water content of the control group is 15.36%, the soil water content of the test group with the attapulgite particle size of 10-30 meshes, the attapulgite particle size of 30-120 meshes and the attapulgite particle size of 200 meshes is 16.18%, 17.32% and 18.26% respectively; and in 7 months, the water content of the control group is 21.49%, and the soil water content of the control group, the attapulgite particle size is 10-30 meshes, the attapulgite particle size is 30-120 meshes and the attapulgite particle size is 200 meshes respectively reaches 21.49%, 22.06%, 22.83% and 22.40%. Due to the affinity of the attapulgite to water molecules, the water content of the test group is obviously larger than that of the control group, and the water content of the soil tends to increase along with the reduction of the particle size of the attapulgite. The smaller the added particle size is, the more beneficial the particle size is to fully contact with water molecules, and the more convenient the particle size is to absorb water. According to FIG. 16, the contents of ammonium nitrogen and nitrate nitrogen in the soil, the improved samples, were significantly greater than the control, and 8 months > 10 months > 6 months. The relative lowest in the test is 6 months, and the ammonium nitrogen content of soil samples of a control group, an attapulgite particle size of 10-30 meshes, an attapulgite particle size of 30-120 meshes and an attapulgite particle size of 200 meshes is 5.76mg/kg, 7.48mg/kg, 9.42mg/kg and 10.53mg/kg respectively; the soil has the highest content of ammonium nitrogen for 8 months, and the contents of the ammonium nitrogen in the soil of the sample formula are respectively 8.36mg/kg, 11.47mg/kg, 15.47mg/kg and 16.34 mg/kg. The time sequence of the content of the nitrate nitrogen in the soil is the same as that of the ammonium nitrogen, wherein the content of the nitrate nitrogen in the soil is the lowest in 6 months, and the content of the nitrate nitrogen in the soil sample of a control group, an attapulgite particle size of 10-30 meshes, an attapulgite particle size of 30-120 meshes and an attapulgite particle size of 200 meshes is 0.13mg/kg, 0.10mg/kg, 0.14mg/kg and 0.16mg/kg respectively; the content of nitrate nitrogen in the soil is 0.50mg/kg, 0.48mg/kg, 0.71mg/kg and 0.64mg/kg respectively for 8 months. The smaller the grain size of the added attapulgite is, the stronger the ability of the sample prescription to generate ammonium nitrogen is, but the influence difference on the nitrate nitrogen is not obvious.

As shown in table 7, the survival rates of the attapulgite-modified tamarix chinensis seedlings with different particle sizes were different. The survival rate of the tamarix chinensis seedlings in the soil improvement test in 5 months is 40.00 percent, but the survival rate in 6 months is 16.67 percent. The survival rates of the tamarix chinensis seedlings in 5 months are respectively 33.33%, 43.33% and 46.67%, and the survival rates of the seedlings are respectively reduced to 20.00%, 26.67% and 26.67% when statistics is carried out for 6-10 months. The effect of different soil conditioners on the life of the tamarix chinensis seedlings is examined from the physiological angle of the life of the tamarix chinensis, and as can be seen from table 8, the plant heights and the crown widths of the tamarix chinensis seedlings of the test groups of the control group, the attapulgite particle size of 10-30 meshes, the attapulgite particle size of 30-120 meshes and the attapulgite particle size of 200 meshes are 30.63cm, 36.83cm, 43.50cm, 44.45cm, 17.54cm, 18.47cm, 20.10cm and 21.03cm respectively. The physiological conditions of the tamarix chinensis seedlings of the test group for soil improvement by the attapulgite rods with different particle sizes are all better than those of the tamarix chinensis seedlings of the control group. Tests show that different sizes of attapulgite are different from each other in soil improvement, and the attapulgite with 200 meshes and 30-120 meshes is better than that with 10-30 meshes, which is related to that the attapulgite with smaller size can generate more ammonium nitrogen for the soil.

Table 7: survival rate of tamarix chinensis seedlings under different particle sizes of soil conditioner

Table 8: physiological conditions of tamarix chinensis seedlings with different grain diameters of soil conditioner

From the biochemical aspect of the tamarix chinensis seedlings under soil improvement by the attapulgite with different particle sizes, it can be seen from fig. 17 that the SOD and POD of the tamarix chinensis seedling leaves of the test groups with the control group, the attapulgite particle size of 10-30 mesh, the attapulgite particle size of 30-120 mesh and the attapulgite particle size of 200 mesh are 201.95 μ/g.fw, 204.74 μ/g.fw, 212.09 μ/g.fw, 215.28 μ/g.fw, 325.62 μ/g.fw, 331.53 μ/g.fw, 345.01 μ/g.fw and 352.18 μ/g.fw respectively, and the MDA is 20.48, 19.49, 18.65 and 17.98umol/g respectively. SOD and POD of tamarix chinensis seedlings in the improved samples with different particle sizes are obviously higher than those of the control sample, and the opposite is true for MDA. The results show that the improved set of tamarix chinensis seedlings have stronger saline-alkali resistance and are less damaged by oxidation when the seedlings face saline-alkali stress. From the biochemical point of view of the tamarix chinensis seedlings, 200 meshes are more than 30-120 meshes and more than 10-30 meshes, which are related to the utilization of ammonium nitrogen in the life history of plants.

Example 8

Influence of different materials covered on surface on improvement of tamarix chinensis community soil of saline marsh wetland

As an alternative embodiment, the surface covering single treatment test was performed with greenhouse film, sand and reed as surface covering materials. The method specifically comprises the following steps: the tamarix chinensis seedlings used in the test are container seedlings, the height of overground seedlings is 10cm, and the average ground diameter is 0.5 cm. The standard of the sample is 1m × 0.5m × 0.5m, 10 seedlings are planted on each sample, and the interval between the samples is 1 m. Each cover material was provided with 3 parallel treatment squares. Processing one: the plastic greenhouse film is 0.lmm in thickness, is cut into 1.5m multiplied by 0.8m, and is compacted with soil around; and (5) processing: sand, covering the sample of the young Chinese tamarisk with the thickness of 5cm, wherein the sand material is common river sand, and the grain size composition is that the grain size composition is greater than 1mm and accounts for 21.24 percent, and less than 0.1mm and accounts for 18.74 percent; and (3) treatment III: the bulrush is paved after being compacted, the thickness is 5-10cm, and the bulrush is collected nearby in the national wetland natural protection area of the yellow river estuary. And (3) when the tamarix chinensis seedlings are transplanted, flood irrigation is carried out on the sample, enough water is poured for root fixing, and then water is not poured again. A control group was prepared without surface coating treatment. The stock sample preparation and the tamarix chinensis seedling transplantation are carried out in 2017 and 4 months.

And (3) test results:

according to the graph shown in fig. 18, the salinity of the sample with the surface covering treatment is obviously lower than that of the control group without the treatment, and the salinity change trend of the sample with the surface covering treatment is more gradual in the soil salinity change in spring and autumn, which indicates that the surface covering can effectively inhibit the soil salinity increase. The reason for this is that the cover layer can obstruct the exchange interface between the soil and the air, so that the evaporation of the soil moisture is inhibited, thereby reducing the accumulation of salt on the surface layer of the soil. As shown in fig. 19, the soil water content of the test sample and the control group was at a minimum in 6 months and peaked in 7 months. Wherein, in 6 months, the water content of the control group is 15.43 percent, and the water content of the soil of the greenhouse film, sand and reed coverage treatment group is 21.77 percent, 20.25 percent and 19.22 percent respectively; and 7, the water content of the control group is 21.92 percent, and the water content of the soil of the greenhouse film, sand and reed coverage treatment group respectively reaches 26.51 percent, 25.01 percent and 24.77 percent. The change of the water content of the soil is related to precipitation, underground water burial depth, vegetation coverage and soil surface covering, and also related to environmental factors causing soil evaporation such as air temperature, wind power and the like. The soil moisture content of the surface covering treatment test group is obviously higher than that of the control group. The covering layer can reduce the evaporation of the water on the surface layer of the soil, and can also lead the evaporated water in the soil to be condensed into water drops under the mulching film and then to drop back to the soil, thereby increasing the water content of the soil. From the water retention properties of the surface covering treatment, greenhouse films > sand > reed, which may be related to the air tightness of three different coverings. According to the overall effect of salt reduction shown in fig. 20, greenhouse film > sand > reed, but in 7 months of monitoring, reed > sand > greenhouse film. This is due to the strength of the barrier of the three materials to the soil-air interface. In the months with less precipitation, the covering material has stronger barrier to the soil and air interface, and can reduce the evaporation and the diffusion of the soil moisture, thereby reducing the accumulation of salt on the surface layer of the soil; however, during the months of concentrated precipitation, the more porous material may cause the soil under the overburden to experience greater leaching salt strength, thereby reducing soil salinity even more.

As shown in table 9, the survival rates of tamarix chinensis seedlings covered by different surface layers were different. The survival rate of tamarix chinensis seedlings in 5 months in the control group is 26.67% by statistics, but the seedlings are not survived in 6 months. In the test group for covering the greenhouse film, the sand and the reed, the survival rates of the 5-month tamarix chinensis seedlings are respectively 36.67 percent, 23.33 percent and 30.00 percent, and the survival rates of the seedlings are respectively reduced to 23.33 percent, 13.33 percent and 16.67 percent when the statistics of 6 months are carried out. From table 10, it can be seen that the plant height and the canopy width of tamarix chinensis seedlings under the greenhouse film, sand and reed covering treatment are 23.34cm, 24.41cm, 26.58cm, 15.89cm, 14.58cm and 16.29cm, respectively, the living condition under the reed covering treatment is the best, and the highest value is considered from the growing angles of the tamarix chinensis plant height and the canopy width, respectively.

Table 9: survival rate of tamarix chinensis seedlings under different surface coverage

Table 10: physiological conditions of Tamarix chinensis seedlings under different surface coverings

From the biochemical perspective of the tamarix chinensis seedlings, the three covering treatments were examined to have effects on the life of the tamarix chinensis seedlings, and as can be seen from fig. 21, the SOD and POD of the tamarix chinensis seedling leaves under the greenhouse film, sand and reed covering treatments were 166.52 μ/g.fw, 161.99 μ/g.fw, 169.56 μ/g.fw, 285.72 μ/g.fw, 288.35 μ/g.fw and 283.84 μ/g.fw, respectively, and the MDA was 22.54umol/g, 22.82umol/g and 22.05umol/g, respectively. The SOD activity and POD activity of the leaves of the tamarix chinensis seedlings under the three types of coverage are not different, and the MDA test data are not greatly different. The biochemical condition of tamarix chinensis at 6 months is illustrated, and no obvious difference exists under the three coverage conditions. The living condition of the tamarix chinensis seedlings covered by the reeds is better than the growth condition of the tamarix chinensis seedlings under the treatment of the greenhouse film and the sand by combining the physiological and biochemical conditions of the tamarix chinensis seedlings. The reed as the covering layer can be decomposed under the action of soil microorganisms, and nutrients for living and growing of plants are released into soil, so that the soil environment of a sample is improved, and the growth and development of tamarix chinensis seedlings are promoted, which is very important in a test sample plot with poor nutrients.

As can be seen from examples 4 to 8, in the environment where the nutrient conditions such as soil salinity is high, soil ammonium nitrogen, nitrate nitrogen and the like are poor in the degraded area of the tamarix chinensis wetland, and the underground water is buried deep and shallow, the salt barrier layer, the soil improvement layer, and the surface covering have various advantages and effects, and if one item is used for restoration and treatment of the degraded tamarix chinensis wetland, the effect cannot reach the target ideal state. If the plants can be combined and optimized to exert respective growth, the method is greatly beneficial to the adaptation of the tamarix chinensis vegetation to the adverse growth environment of the degraded area, thereby promoting the recovery of the tamarix chinensis vegetation and the reconstruction of the degraded tamarix chinensis wetland. According to the method, a tamarix chinensis pit is dug, a salt isolation layer is laid at the bottom of the pit to reduce the salt content of the soil in the pit, the soil conditioner is mixed with in-situ soil for backfilling, and after backfilling, a ground surface covering material is laid to inhibit the evaporation of the soil water, so that a 'good isolation and reduction' comprehensive technical matching measure of preventing the loss of the middle layer soil improvement and reducing the evapotranspiration of the upper layer is constructed.

Example 9

Influence of different optimized combinations on improvement of tamarix chinensis community soil of salt marsh wetland

Specifically, the method comprises the following steps: the material used in the salt isolation layer is sand, the bottom layer of the sample square is paved with 20cm, the distance between the sand layer and the ground surface is 30cm, the sand material is common river sand, and the particle size composition is>1mm accounts for 21.24 percent,<18.74% for 0.1 mm; the middle layer filler adopted by the soil improvement technology is attapulgite (30-120 meshes), after the sample is filled with soil 20cm in situ, ammonium sulfate ((NH)₄)₂SO₄)50g, mixing the attapulgite with the in-situ soil in a ratio of 1:3 in a sample prescription, wherein the thickness of the mixed layer is 30cm below the ground surface; the surface layer covering material is a plastic greenhouse film, the film thickness is 0.lmm, the specification is 1.5m multiplied by 0.8 m', and different optimization combination comparison tests are respectively carried out in a surface covering and salt isolation layer treatment mode, a surface covering and soil improvement technology treatment mode, a salt isolation layer and soil improvement technology treatment mode and a good isolation and subtraction combined mode. The tamarix chinensis seedlings used in the test are container seedlings, the height of overground seedlings is 10cm, and the average ground diameter is 0.5 cm. The standard of the sample is 1m multiplied by 0.5m, each sample has 10 seedlings and samplesThe interval between the blocks is 1 m. Each combination mode is provided with 3 parallel processing samples. In addition, a control group was not treated.

And (3) test results:

according to FIG. 22, the salinity of the control group, the surface cover + salt barrier combination, the salt barrier + soil improvement combination, the surface cover + soil improvement combination, the "good barrier" combination is 7.27ppt, 5.92ppt, 6.23ppt, 5.45ppt and 5.24ppt respectively after 6 months; the salinity of each soil in 8 months is 4.42ppt, 3.26ppt, 3.36ppt, 3.19ppt and 3.17ppt respectively, and the inhibiting effect of each optimized combination on the salinity of the soil in the test is that the combination of 'good reduction' is greater than the combination of surface covering and salt separating layer is greater than the combination of surface covering and soil improvement is greater than the combination of salt separating layer and soil improvement mode, and the combination of 'good reduction' is optimal.

As shown in fig. 23, the water content of each test group and the control group reached the maximum value at 7 months. For 6 months, the water content of the control group is 15.43 percent, and the water content of the soil in the sample of the surface covering + salt isolation layer combination, the salt isolation layer + soil improvement combination, the surface covering + soil improvement combination and the 'Liangjian' combination is 20.99 percent, 16.58 percent, 22.35 percent and 21.35 percent respectively; in 7 months, the water content of the control group is 21.49%, and the water content of the soil in the combination of surface covering + salt-separating layer combination, salt-separating layer + soil improvement combination, surface covering + soil improvement combination and 'Liangjian' combination is 25.91%, 22.59%, 27.26% and 26.46%, respectively. The reason why the soil moisture content of the "good and poor isolation" combination is slightly less than that of the surface covering and soil improvement combination is probably because the salt isolation layer in the "good and poor isolation" combination cuts off the continuous capillary action between the soil surface layer and the soil of the lower layer, so that the passage of the water of the lower layer to the upper layer is blocked, and the moisture content of the soil surface layer is influenced. From the water salt condition of soil, the 'good isolation and reduction' combination can not only best reduce the accumulation of salt content of surface soil, but also reserve enough moisture for the soil, so that the soil is in a relatively arid period, a good soil water environment is provided for the root system water absorption of the tamarix chinensis seedlings, the physiological water shortage of the tamarix chinensis seedlings in a high-salt period is better prevented, and the survival of the seedlings is promoted.

As shown in fig. 24, in terms of the salt reduction rate, "good reduction" combination > surface coverage + salt barrier combination > surface coverage + soil improvement combination > salt barrier + soil improvement combination.

According to the graph of fig. 25, the ammonium nitrogen content of the soil of the samples, the ammonium nitrogen and nitrate nitrogen content of the optimally combined samples were significantly greater than the control group, and the nitrogen content of each group was 8 months > 10 months > 6 months in time. The lowest in the test is 6 months, and the ammonium nitrogen contents of soil samples of a nitrogen application control group, a salt separation layer and soil improvement combination, a surface covering and soil improvement combination and a good reduction combination sample are 5.76mg/kg, 10.93mg/kg, 11.25mg/kg and 11.16mg/kg respectively; the content of ammonium nitrogen in the soil is 8.36mg/kg, 14.62mg/kg, 19.08mg/kg and 17.81mg/kg respectively in the maximum period of 8 months. The content of soil ammonium nitrogen, the combination of surface coverage + soil improvement was slightly greater than the "poor at break" combination, which may be due to the "poor at break" combination (NH)₄)₂SO₄The method is applied to the salt-separating layer, and when a large amount of rainwater is leached and dissolved, ammonium nitrogen enters the salt-separating layer, and the ammonium nitrogen is more easily lost in a lower soil layer because the capillary force of the soil is cut off. Therefore, the position to which ammonium nitrogen is applied is also one of the points to be noted when restoring wet land actually with ammonium sulfate. The time sequence of the content of the soil nitrate nitrogen is the same as that of ammonium nitrogen, wherein the content of the soil nitrate nitrogen is the lowest in 6 months, and the content of the soil nitrate nitrogen in a soil sample of a nitrogen application control group, a salt isolation layer and soil improvement combination, a surface covering and soil improvement combination and a good isolation and reduction combination is respectively 0.13mg/kg, 0.15mg/kg, 0.21mg/kg and 0.22 mg/kg; the content of nitrate nitrogen in the soil is 0.50mg/kg, 0.71mg/kg, 1.09mg/kg and 0.93mg/kg respectively when the soil is used for 8 months. It can be seen that the content of nitrate nitrogen in the soil sample of the salt separation layer and soil improvement combination is obviously less than that of the other three optimized combinations, which is probably because the salt inhibiting capability of the combination is weaker than that of the other three combinations, soil microorganisms are not better in nitrification environment, and moreover, because the combination has no surface covering measure, the soil is more easily leached when heavy rainfall occurs, and the loss of the nitrate nitrogen is aggravated.

As shown in table 11, the survival rates of tamarix chinensis seedlings were different for the different optimized combinations. The survival rate of tamarix chinensis seedlings in the control group at 5 months was 26.67%, whereas no tamarix chinensis seedlings survived at 6-10 months. The survival rates of the 5-month tamarix chinensis seedlings are 46.67%, 66.67%, 70.00% and 86.67% respectively, and the survival rates of the seedlings are 33.33%, 43.33%, 36.67% and 66.67% respectively when counted in 6-10 months. The optimized combination formula is significantly higher than the control formula. The highest survival rate of the combined Chinese tamarisk seedlings is the 'good reduction' combination, because the 'good reduction' combination can well control the soil salinity to a level which can be adapted by the Chinese tamarisk seedlings, and effectively enhances the survival capability of soil sample ammonium nitrogen, so that the Chinese tamarisk seedlings have enough ammonium nitrogen supply when the salt stress is strongest, thereby enhancing the physiological resistance of salt and alkali.

As shown in Table 12, the plant heights and crown widths of Tamarix chinensis seedlings of the same species as the surface covering + salt barrier layer combination, the salt barrier layer + soil improvement combination, the surface covering + soil improvement combination and the "Liangjian reduction" combination were 27.09cm, 45.44cm, 47.09cm, 50.16cm, 16.27cm, 21.67cm, 22.38cm and 25.89cm, respectively. The physiological conditions of the tamarix chinensis seedlings of the test group with the soil improvement measure are all better than those of the tamarix chinensis seedlings without the soil improvement measure (surface covering plus salt barrier layer combination sample). The nitrogen element is supplemented to the nitrogen-deficient soil environment, the growth of the tamarix chinensis seedlings in the degenerated area can be remarkably promoted, and the restoration and reconstruction of the tamarix chinensis community are obviously promoted.

Table 11: survival rate of tamarix chinensis seedlings under different optimized combinations

Table 12: physiological conditions of Tamarix chinensis seedlings under different optimized combinations

From fig. 26, it can be seen that SOD and POD of leaves of tamarix chinensis seedlings of different optimized combination samples are 185.20 μ/g.fw, 216.21 μ/g.fw, 219.65 μ/g.fw, 235.50 μ/g.fw, 303.41 μ/g.fw, 363.49 μ/g.fw, 365.24 μ/g.fw, 395.47 μ/g.fw, and MDA is 21.37, 17.43, 17.62, and 16.85umol/g, respectively, from the biochemical perspective of tamarix chinensis seedlings. Therefore, the SOD and POD of the tamarix chinensis seedlings combined by the 'Liangliang reduction' are the highest, and the MDA is the lowest. The results show that the tamarix chinensis seedlings with the combination of 'Lianliang reduction' have the most active antioxidant enzymes and the least damage to cell membrane lipids in 6 months with the strongest salt and alkali stress. The quantity of SOD and POD generated by the tamarix chinensis after being damaged by saline and alkaline also has the tendency of increasing firstly and then weakening along with the strength of saline and alkaline stress, the salinity of the 'good-isolation' combination is lower than that of other formulas, and the generated SOD and POD are more than that of other formulas, so that the tamarix chinensis is better prevented from being damaged by the stress of high salinity from the aspect of cell physiology. Therefore, the biochemical conditions of the tamarix chinensis seedlings living under the 'good isolation and reduction' combination are the best comprehensively.

In summary, the optimization of the degenerated environment and the promotion of the survival and growth of tamarix chinensis seedlings have excellence in each combination: on the aspects of reducing the high salt stress of the tamarix chinensis and reducing the soil salt content, the combination of the surface layer covering layer and the salt isolation layer and the combination of good isolation and reduction show good effects; the combination of surface covering, soil improvement and 'Liangliang reduction' has good effect on improving the water content of soil and avoiding physiological water shortage of the tamarix chinensis seedlings; the 'good isolation and reduction' combination is best in the aspects of improving the nitrogen content of soil, enhancing the saline-alkali stress resistance of the tamarix chinensis and promoting the growth and development of seedlings. In summary, the 'Liangmei' combination can effectively improve the survival rate of the tamarix chinensis seedlings in severe degraded tamarix chinensis wetlands and can also effectively promote the growth and development of the tamarix chinensis seedlings.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.