CN215991869U - Coastal saline and alkaline land greening system based on landscaping waste utilization - Google Patents

Abstract

The utility model discloses a coastal saline-alkali land greening system based on garden greening waste utilization, which comprises a covering layer, a soil layer to be improved, a permeable membrane layer, a leaching layer, a concealed pipe salt drain, a salt drain well, a vent hole, a waterproof layer and a saline-alkali soil layer which are sequentially arranged from top to bottom; the covering layer is arranged on the ground surface near the root of the soil plant; the soil layer to be improved is a mixture of undisturbed saline soil, decomposed landscaping branch and leaf crushed materials and other organic and inorganic fertilizers; the leaching isolation layer is made of crushed garden branch, trunk or tree root waste; the concealed conduit salt discharge ditch is positioned below the leaching isolation layer. The system not only can fully utilize organic matter resources such as regional landscaping wastes and the like, enhance the salt washing and discharging efficiency, effectively reduce the underground water level, prevent salt return, reduce surface evaporation, increase the soil fertility, and realize the purpose of improving the saline soil. The damage to cultivated land resources can be reduced, the resource use is saved, and the resource utilization of landscaping wastes is realized.

Description

Coastal saline and alkaline land greening system based on landscaping waste utilization

Technical Field

The utility model belongs to the technical field of saline-alkali soil greening, and particularly relates to a coastal saline-alkali soil greening system based on garden greening waste utilization.

Background

The coastal saline-alkali soil in China is widely distributed, and the statistical total area reaches 500 multiplied by 10⁴hm². Coastal saline soil has the problems of high underground water level, poor soil permeability, difficult leaching and the like in areas, and salt is accumulated on the ground surface due to large evaporation amount, so that the salt content of the soil exceeds the bearing limit of plants, salt damage is formed, and the plants are difficult to survive. With the development of economy and industry in the years, saline-alkali areas have become new places for economic development, and various methods for treating saline-alkali soil are widely applied in order to meet the requirements of construction and development. Wherein the combination of the planting of the foreign soil and the stone chip sprinkling layer "The method for treating saline-alkali soil by concealed conduit salt elimination becomes a common method for landscaping engineering construction. The method can obviously reduce the underground water level, prevent the salt from returning to the foreign soil, and simultaneously drain the salt in the soil body, thereby realizing the plant planting. However, with the economic development and social progress, the soil for the foreign land needs a large amount of planting soil, which is not only high in cost, but also seriously destroys the cultivated land, is a governing mode of 'green side and destroyed side', and is contrary to the cultivated land policy, ecological environmental protection policy and sustainable development policy implemented by the state.

At present, materials used by the 'stone chip drenching layer' technology are generally building broken stones (stone chips), remarkable effects are achieved in the aspects of drainage desalination and salt return control, but with exhaustion of stone resources, the transport distance is continuously increased, the price of the broken stones is increased, the cost of greening construction of a saline area is further increased, and adverse effects are undoubtedly brought to improvement of saline-alkali soil in the coastal area. Under the background, it is necessary to select one or more alternative materials with the characteristics of relatively stable property, economical price, easy obtaining and easy processing, and the like, and the alternative materials can meet the requirements of the existing landscaping of the area.

The resource utilization of landscaping wastes is a major problem which troubles the development of urban landscaping, most of urban garden wastes are mainly buried, burned, stacked on site and the like, the concept and the original intention of urban green development are violated, the urban attractiveness is influenced, and the urban environment is polluted. If the treatment is not carried out in time, fire hazards also exist in a large amount of stacking. The garden waste is divided into difficultly decomposed matters such as branches and the like containing more lignin and easily decomposed matters such as leaves and herbs containing more cellulose, the garden branch crushing waste is a crushed product of branch waste generated by garden greening pruning or natural updating, the waste contains lignin, the process is extremely slow through natural degradation, the waste belongs to the difficultly decomposed matters, and how to perform resource, harmless and reduction treatment on the garden greening waste becomes another problem to be solved by the current content.

SUMMERY OF THE UTILITY MODEL

The technical problem to be solved by the utility model is to provide a coastal saline-alkali land greening system based on garden greening waste utilization; aiming at the problems of high underground water level, poor soil permeability, large evaporation capacity, difficult plant survival and the like in a coastal saline soil area, and the situations of lack of foreign soil resources, high macadam cost and the like, the method is difficult to realize that landscaping wastes are difficult to treat and utilize. The method has the advantages that the method is innovative, the garden greening tree branches, leaves, barks and other wastes are classified and treated, the wastes are classified and applied to improvement of the coastal saline soil, through reducing underground water level, leached salt is discharged, soil permeability is increased, desalting efficiency is improved, soil fertility is enhanced, surface evaporation is reduced, surface salt accumulation is prevented, secondary salinization is avoided, finally, original soil greening of the coastal saline soil is realized, recycling, harmlessness and reduction treatment of garden greening wastes are realized, and important technical support is provided for non-waste cities, water-saving cities, ecological cities and park cities.

In order to solve the technical problem, the utility model adopts the following technical scheme：

The utility model relates to a coastal saline-alkali soil greening system based on garden greening waste utilization, which comprises a covering layer, a soil layer to be improved, a permeable membrane layer, a leaching layer, a concealed pipe salt drain ditch, a salt drain well, a vent hole, a waterproof layer and a saline-alkali soil layer which are sequentially arranged from top to bottom;

the covering layer is arranged on the ground surface near the root of the soil plant;

the leaching isolation layer is made of crushed garden branch, trunk or tree root waste;

the concealed pipe salt discharge ditch is positioned below the leaching layer and protrudes into a groove of a saline-alkali soil layer, and a concealed pipe is arranged in the groove;

the slope direction of the concealed pipe is connected with a communicated salt discharge well;

the vent hole extends downwards from the soil layer to be improved to the permeable membrane layer;

the salt discharge wells are arranged in the soil body at intervals, the depth of the salt discharge wells extends into the saline-alkali soil layer from top to bottom, and the salt discharge wells are communicated with a municipal drainage system, a landscape water body or rivers and lakes through drainage pipes.

Preferably, the covering layer material is leaves, dried barks or crushed pieces of branches, and the thickness is 0.5-20 cm.

Preferably, the soil layer to be improved is undisturbed saline soil; more preferably, the soil layer to be improved is a mixture of undisturbed saline soil and decomposed landscaping branch and leaf crushed materials and other organic and inorganic fertilizers.

Preferably, the thickness of the soil layer to be improved is 60-150 cm; the mixing proportion of the decomposed branch and leaf crushed materials for landscaping and other organic and inorganic fertilizers is 10-50%, and the other organic and inorganic fertilizers are configured according to the needs of soil plants.

Preferably, the water permeable film layer is a water permeable nonwoven fabric.

Preferably, the thickness of the leaching layer is 20-50cm, and the length of the garden green plant waste crushed material is 0.5-3 cm.

Preferably, the hidden pipes are arranged at intervals of 7-9 meters, are PVC infiltration pipes and can be coated with water-permeable geotextile.

Preferably, the salt discharge ditches are arranged on the upper layer of the saline-alkali soil at intervals, the arrangement distance is 6-8 meters, and the width and the depth are 25-45 cm.

Preferably, the drain pipe is a PVC seepage pipe; more preferably, a plurality of rows of narrow-strip-shaped water seepage holes can be formed in the circumference, and the requirements of different ring rigidity and permeability can be met by controlling the opening rate; the drainage pipe is communicated with the salt drainage well, a municipal drainage system, a landscape water body or a river or lake; the central elevation of the drainage pipe is not lower than the top of the leaching isolation layer.

Preferably, a lateral waterproof layer is used to turn up where the greening system meets the surrounding building or structure.

Preferably, a waterproof layer is arranged between the leaching insulation layer and the saline-alkali soil layer.

Any range recited herein is intended to include the endpoints and any number between the endpoints and any subrange subsumed therein or defined therein.

The starting materials of the present invention are commercially available, unless otherwise specified, and the equipment used in the present invention may be any equipment conventionally used in the art or may be any equipment known in the art.

Compared with the prior art, the utility model has the following beneficial effects:

on the basis of original saline soil, the ground material of garden greening branches is innovatively adopted to replace conventional stone chips to serve as a leaching isolation layer, decomposed materials such as tree leaves and branch wastes of garden greening are used as saline soil blending and improving materials, meanwhile, the ground surface is covered by the ground material or dried bark, organic waste resources such as regional garden greening wastes are fully utilized, water evaporation is reduced, the physical structure of the saline soil is improved, permeability is increased, soil fertility is increased, fertilizer and water are preserved and saved, under the action of natural rainfall and irrigation, salt washing and discharging efficiency is enhanced, the underground water level is reduced, and the purpose of improving the saline soil is achieved. The method reduces the damage to cultivated land resources, saves the use of building material resources such as stone chips and the like, realizes the resource utilization of landscaping wastes, has important significance for the recovery of the regional ecological environment, and provides important technical support for realizing non-waste cities, water-saving cities, ecological cities and park cities in coastal saline areas. From the economic perspective, the original soil planting does not increase the construction cost, reduces the garden waste disposal cost, and also reduces the maintenance water, and in the long run, the mode more accords with the direction and the requirement of green environmental protection and sustainable development.

Drawings

The following detailed description of embodiments of the utility model is provided in connection with the accompanying drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic structural view of a section of a soil body of the saline-alkali soil greening system of the utility model;

FIG. 3 is a graph showing the change of the salt content of topsoil (sampled at 30cm below the surface of the earth) with sampling time in Experimental example 1;

FIG. 4 is a graph showing the change of the salt content of the middle layer soil (sampled at 60cm below the surface of the earth) with the sampling time in Experimental example 1;

FIG. 5 is a graph showing the change of the salt content of the subsoil (sampled at a position 90cm below the surface of the earth) with the sampling time in Experimental example 1;

FIG. 6 is a graph showing the change of pH of topsoil (sampled at 30cm below the surface of the earth) with sampling time in Experimental example 1;

FIG. 7 is a graph showing the change of pH of medium soil (sampled at 60cm below the surface of the earth) with sampling time in Experimental example 1;

FIG. 8 is a graph showing the change of pH of subsoil (sampled at 90cm under the surface of the earth) with sampling time in Experimental example 1;

FIG. 9 is a graph showing the trend of total salt content in the soil of high saline soil in Experimental example 2;

FIG. 10 is a graph showing the trend of the total salt content of the soil with low saline soil content in Experimental example 2;

FIG. 11 is a graph showing the pH variation trend of the high saline soil in Experimental example 2;

FIG. 12 is a graph showing the trend of pH change of saline soil with low content in Experimental example 2.

FIG. 13 is a bar graph showing the variation tendency of pH and total salt content of soil in Experimental example 2.

Detailed Description

In order to more clearly illustrate the utility model, the utility model is further described below in connection with preferred embodiments. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the utility model.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings that is solely for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and is therefore not to be construed as limiting the utility model.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the prior art, the soil improvement of the saline-alkali soil mainly adopts a soil-removing method, a terrain elevation method, a buried pipe burying method and other methods, but with the economic development and the social progress, the soil-removing method and the terrain elevation method need a large amount of planting soil, the cost is high, the farmland is seriously damaged, the method is a management mode of green side and damaged side, and the method is contrary to the farmland policy, ecological environment protection policy and sustainable development policy which are pushed by the state.

In the prior art, the traditional leaching layer material generally uses the building rubble, has obtained showing the effect in the aspect of drainage desalination and control salt return, but along with the exhaustion of stone resource, the continuous increase of freight distance, the rubble price increases, has further promoted the cost of salinization district afforestation construction, undoubtedly brings unfavorable influence for coastal area saline and alkaline land improvement. Under the background, it is necessary to select one or more alternative materials with the characteristics of relatively stable property, economical price, easy obtaining and easy processing, and the like, and the alternative materials can meet the requirements of the existing landscaping of the area.

The resource utilization of garden wastes is a great problem which troubles the urban greening development, most of garden wastes in cities are mainly buried, burned, stacked on site and the like, the concept and the original intention of urban green development are violated, the urban attractiveness is influenced, and the urban environment is polluted. How to carry out resource, harmless and reduction treatment on the garden waste becomes another problem to be solved by the current letter.

In view of the above, as one aspect of the present invention, a coastal saline-alkali soil greening system based on landscaping waste utilization comprises, sequentially from top to bottom, a covering layer 9, a soil layer 1 to be improved, a permeable membrane layer 2, a leaching layer 3, a concealed pipe salt drain ditch 4, a waterproof layer 8 and a saline-alkali soil layer 5;

the covering layer 9 is made of leaves, dried barks or crushed branches, and the covering thickness is 0.5-3 cm.

The soil layer 1 to be improved is a mixture of undisturbed saline soil, decomposed landscaping branch and leaf crushed materials and other organic and inorganic fertilizers;

the leaching isolation layer 3 is made of crushed garden branch, trunk or tree root waste; the concealed pipe salt discharge ditch is positioned below the water-separating layer and protrudes into a groove of a saline-alkali soil layer, and a concealed pipe is arranged in the groove.

The lower surface of the concealed pipe salt drain ditch 4 is provided with a groove 41 which protrudes into a saline-alkali soil layer, and a concealed pipe 42 is arranged in the groove;

the concealed pipe 42 is connected with the communicated salt discharge well 6 in a slope direction;

the salt discharge wells 6 are arranged in the soil body at intervals, the depth of the salt discharge wells extends into the saline-alkali soil layer 5 from top to bottom, and the salt discharge wells are communicated with a municipal drainage system, a landscape water body or rivers and lakes through drainage pipes;

a waterproof layer is arranged between the leaching insulation layer and the saline-alkali soil layer;

the soil layer 1 to be improved is provided with a vent hole (not marked in the figure) which extends downwards from the soil layer 1 to be improved to the permeable membrane layer 2.

In the present application, the term "soil mass" refers to a general term from surface soil to deep soil.

According to certain embodiments of the present application, the soil layer 1 to be amended has a thickness of 60-150 cm.

According to certain embodiments of the present application, the water-permeable film layer 2 is a water-permeable nonwoven fabric.

It can be understood that the existing landscaping mill scraps are mainly divided into three types, 1) scrap scraps of branches, trunks or roots (these materials are very difficult to degrade, are not afraid of water soaking and may eventually become carbon); 2) rotten clinker of leaf and grass wastes; 3) bark waste. In this application, afforestation abandonment is smashed the thing and can only select first, also the afforestation abandonment is smashed the thing and is the discarded object crushed aggregates of the discarded branch of afforestation, trunk, root, can not use leaf grass class discarded object rotten grog etc..

According to some embodiments of the present application, the thickness of the leaching layer 3 is 25-45cm, and the particle size or length of the crushed material of the garden branches, trunks or roots is 0.5-3 cm.

According to some embodiments of the present application, the concealed pipes 42 are arranged one by one at intervals of 7-9 meters, the concealed pipes are PVC seepage pipes, and the concealed pipes are externally coated with a water-permeable geotextile.

According to certain embodiments of the present application, the salt discharge ditches are arranged on the upper layer of the saline-alkali soil at intervals of 6-8 meters, and the width and the depth of the salt discharge ditches are 25-45 cm.

According to some embodiments of the present application, the drain pipe 7 is a PVC seepage pipe; more preferably, a plurality of rows of narrow strip-shaped water seepage holes are formed in the circumference of the drain pipe, and the requirements of different ring rigidity and permeability can be met by controlling the opening rate; and the drain pipe 7 is communicated with the salt draining well 6 and a municipal drainage system, a landscape water body or rivers and lakes.

According to some embodiments of the present application, a lateral waterproof layer turn-up is employed at the interface of the greening system and surrounding buildings or structures; thereby having the function of collecting and utilizing sponge urban water resources and being used for irrigating greenbelts and the like.

According to some embodiments of the present application, a waterproof layer 8 is provided between the leaching layer 3 and the saline-alkali soil layer 5.

The working principle of the coastal saline-alkali soil greening system based on garden greening waste utilization is as follows:

the leaching isolation layer plays an important role in a concealed pipe salt discharge system, on one hand, the rising of the underground water level can be isolated, and the capillary action of soil can be broken; on the other hand, when soil is in waterlogging, under the soil water supersaturation state, the moisture has realized vertical and horizontal transmission and migration through separating and drenching the layer, through separating and drenching the built-in blind pipe of layer, reaches the effect of drainage salt discharge. The utility model adopts the garden green plant waste powder as the leaching isolation layer, has the characteristics of large pores, difficult degradation, certain bearing capacity and the like, and can effectively reduce the underground water level and drain leaching salt.

The landscaping waste belongs to an organic natural soil conditioner, is taken from a greening plant and is taken as a landscaping green land. Landscaping waste covers the ground surface or is applied to the soil after being crushed, and has 5 remarkable effects: (1) improve the physical and chemical properties of soil. The organic matter of the soil can be increased, the soil fertility and the nutrient utilization rate can be improved, the soil granular structure can be improved, the soil pH value can be adjusted, the soil ventilation performance and the water permeability can be improved, and the soil moisture and temperature stability can be maintained. (2) And the soil biological activity is enhanced. The covering layer of the dead branches and fallen leaves provides sheltering habitat for small organisms such as ground surface insects, earthworms and the like, provides energy and food for decomposers and enriches soil animal communities. Meanwhile, the supplement of carbon also influences the types, the quantity and the activity of soil enzymes. (3) Promoting the growth of garden plant seedlings. Can improve the survival rate of seedlings, enhance the growth vigor of plants and increase the height and biomass of the plants. (4) Inhibiting the growth of weeds. The waste covering reduces the fluctuation range of the day and night temperature difference, reduces direct sunlight on the exposed surface, reduces the allelopathy of waste decomposition liquid, and inhibits the germination and growth of weed seeds. (5) And the urban sponge effect is enhanced. The surface layer roughness can be increased by the decomposed dry branch crushed materials, leaves, grass and the like, the surface runoff speed is slowed down and prolonged, the soil erosion is prevented, the rainwater infiltration of urban green lands is increased, the surface water accumulation is reduced, and the rainwater utilization rate is improved.

In-process at rain and watering, this application the rainwater on coastal saline and alkaline land greening system surface is at first filtered through the overburden, treat the improvement soil layer and drip washing, then take away partial salinity wherein and enter into behind the permeable membrane layer and separate and drench the layer, separate and drench the layer and can promote moisture lateral migration between the soil body, there are more water and drench the layer through separating and drench the direction salt drain ditch, and then arrange the salt with higher speed, get into the salt drainage well, the capillary action of high salt groundwater is separated and drenched the layer and is interrupted, the groundwater that rises and drench after the water under the action of gravity is arranged into regional river course, landscape water and municipal rainwater pipeline through the concealed pipe down. The water-proof layer and the water drain pipe are arranged in an overflowing manner, so that the water resource can be collected, regulated and stored, and the water can be irrigated and greened for use.

In dry seasons, ground surfaces are covered by the crushed materials, so that soil moisture evaporation can be reduced, soil moisture and temperature stability can be maintained, and salt accumulation can be prevented. The crushed material is used as a salt isolation layer, so that the capillary action of high-salt underground water can be broken, and the surface accumulation of water and salt can be prevented.

The utility model adopts the garden greening branch crushed materials to replace conventional stone chips as a spraying separation layer, utilizes decomposed materials such as garden greening leaf and branch wastes to serve as a saline soil blender material, adopts the crushed materials to cover the ground surface, fully utilizes organic waste resources such as regional garden greening wastes, enhances the salt washing and removing efficiency, reduces the underground water level, reduces evaporation in dry seasons, simultaneously blocks the underground water from rising through capillary action, and realizes the purpose of improving the saline soil.

Note that: the existing soil to be improved comprises saline soil, salt is still in the soil, the salt content or the conductivity of collected water needs to be detected, irrigation can be carried out only by meeting the salt content of water for landscaping irrigation, water which is not satisfied is drained, detection is not needed after the irrigation is achieved, or salt water which is leached for the first time and the second time needs to be drained. Then desalting, and irrigating and utilizing water circularly.

Example 1

A coastal saline-alkali soil greening system based on garden greening waste utilization comprises a covering layer 9, a soil layer 1 to be improved, a permeable membrane layer 2, a leaching layer 3, a concealed pipe salt drain ditch 4, a waterproof layer 8 and a saline-alkali soil layer 5 which are sequentially arranged from top to bottom;

the covering layer is made of crushed materials of leaves, dried barks or branches, and the covering thickness is 0.5-20 cm.

The leaching isolation layer 3 is made of crushed garden branch, trunk or root waste;

the lower surface of the concealed pipe salt drain ditch 4 is provided with a groove 41 which protrudes into a saline-alkali soil layer, and a concealed pipe 42 is arranged in the groove;

the concealed pipe 42 is connected with the communicated salt discharge well 6 in a slope direction;

the salt discharge wells 6 are arranged in the soil body at intervals, and the depth of the salt discharge wells extends into the saline-alkali soil layer 5 from top to bottom;

the wall of the salt discharge well 6 is provided with a drain pipe 7, and the salt discharge well is communicated with a municipal drainage system, a landscape water body or a river and a lake through the drain pipe;

the thickness of the layer to be improved is 150 cm;

the permeable film layer is a permeable non-woven fabric;

the thickness of the spray layer is 45cm, and the length of the landscaping waste crushed material is 3 cm;

the hidden pipes are arranged at intervals of 9 meters, are PVC seepage pipes and can be coated with water-permeable geotextile;

the salt discharge ditches are arranged on the upper layer of the saline-alkali soil at intervals, the arrangement distance is 8 meters, and the width and the depth are both 45 cm;

the drain pipe is a PVC seepage pipe; a plurality of rows of narrow strip-shaped water seepage holes are formed in the circumference of the water drainage pipe, and the requirements of different ring rigidity and permeability are met by controlling the opening rate; the drainage pipe is connected with the communicated salt drainage well and a municipal drainage system, a landscape water body or rivers and lakes.

And a waterproof layer 8 is arranged between the leaching layer and the saline-alkali soil layer.

Example 2

Example 1 was repeated with the only difference that:

the thickness of the soil layer to be improved is 60 cm;

the thickness of the spray layer is 35cm, and the length of the landscaping waste crushed material is 0.5 cm;

one concealed pipe is arranged at intervals of 7 meters;

the salt discharge ditch interval sets up on saline-alkali soil upper strata, and the setting interval is 6 meters, and width and degree of depth are 35 cm.

Example 3

Example 1 was repeated with the only difference that:

the thickness of the soil layer to be improved is 120 cm;

the thickness of the spray layer is 40cm, and the length of the landscaping waste crushed material is 1.8 cm;

one concealed pipe is arranged at intervals of 8 meters;

the salt discharge ditches are arranged on the upper layer of the saline-alkali soil at intervals, the arrangement distance is 7 meters, and the width and the depth are 40 cm.

Experimental example 1

Example 1 was repeated with the only difference that: the coastal saline-alkali soil greening system is not provided with a leaching layer.

Experiments prove that:

the comparative test of the material of the leaching barrier sets 3 treatments, which are respectively: a reed area (L), a crushed material area (F) and a non-drenching area (D). Firstly, slotting annual reed straws in a reed area (L), normally making blind ditches, crossing and placing the reeds at the bottom of a tank in a staggered way, wherein the laying thickness is 50cm, and the earth surface is covered with soil of 1.0-1.2 m; secondly, crushing the branches of the trees and shrubs to 0.5-3cm in a crushed material area (F), normally making blind ditches after grooving, paving the crushed materials at the bottom of the tank with the paving thickness of 40cm, and covering the ground surface with soil of 1-1.2 m; thirdly, no spraying layer area (D) exists, after grooving, a blind ditch is normally made, no spraying layer is arranged, and the distance from earth surface to the blind ditch is 1-1.5 m.

The material contrast test area of the leaching-resistant layer is positioned in a new test base of the municipal landscape company Limited in Tianjin ecological city, the Taiqi road of the north area of the New Tianjin ecological city and the 79# land of the east side of the second street are located in the address, and the floor area is about 3 ten thousand square meters. The test is completed at the bottom of 11 months in 2018, soil is frozen and thawed due to the fact that the test enters winter, sampling is started until 5 months in 2019, and soil taking is carried out for 7 times respectively at 28 days in 5 months, 12 days in 6 months, 10 days in 7 months, 13 days in 8 months, 11 days in 9 months, 21 days in 10 months and 22 days in 11 months. The position is recorded by the label when sampling for the first time, and the backfilling area is avoided when soil is taken subsequently, but the distance is not more than 3 meters from the label. Taking soil by adopting a manual hole digging mode at positions of 30cm, 60cm and 90cm respectively, sampling the soil at each level by about 1000g, and filling the soil into self-sealing bags with numbers for later use. The main detection indexes of the soil sample comprise soil salt content, pH value, organic matters, ammonia nitrogen, available phosphorus, potassium ions, calcium ions, magnesium ions, sodium ions and chloride ions.

(1) Change of salt content of soil:

referring to fig. 3-5, it can be seen that, through continuous sampling monitoring for 7 months, soil salinity tends to increase first, then decrease, then increase and then decrease along with sampling time, and the regulation efficiency of different barrier materials on soil salinity migration is not consistent. The salt content of the soil treated by each test is represented in different soil layers as follows:

A. topsoil (sampling 30cm under the surface)

From the end of 5 months to the beginning of 6 months, the D treatment and the L treatment show an ascending trend except the F treatment in each treatment, the highest value is reached at the beginning of 6 months, the soil salinization degree also reaches the level of heavily salinized soil, and the soil shows an obvious salt accumulation phenomenon in the period. From the beginning of 6 months to the beginning of 8 months, all treatments showed a trend of significant decline, wherein the soil salinity of the D-treatment, the F-treatment and the L-treatment in the 8 months was 1.70g/kg, 1.20g/kg and 1.80g/kg, respectively, and the soil salinity was substantially restored to the mild salinization level. In the beginning of 8 months to the end of 11 months, the salt content of the D-treated soil and the L-treated soil firstly decreases and then increases, while the salt content of the F-treated soil stops decreasing, and then the D-treated soil and the L-treated soil change to an increasing state and then decrease. The results show that even under the condition of applying the leaching barrier, the soil salinity migration follows the seasonal variation law.

In each treatment, the seasonal variation rules of the soil salinity are basically consistent between the treatment of the control group D and the treatment of the leaching layer L, the effect of the two treatments on the inhibition of soil salinity accumulation in 5-6 months is not obvious, but the desalting time is obviously delayed by two months in rainy season, and as the leaching layer (reed straws) promotes the transverse migration of moisture among soil bodies, more water is guided to the blind pipe ditch through the leaching layer, and the salt discharge is accelerated. The crushed material spray-separating layer (F treatment) has a sawtooth-shaped descending trend as a whole, wherein before rainy season (before 6 months), the treated plots are severe in drought and water shortage, and the soil capillary action is not obvious; after the rain season, in 6 to 7 months, the soil body moisture is supplemented along with rainfall, the capillary action is enhanced, and meanwhile, the evaporation capacity is greater than the rainfall capacity, which is expressed as the increase of soil salinity; in 8 months, the salt content of the soil is obviously reduced along with the increase of rainfall; after 8 months, the concentrated rainfall is finished, the plot is high in topography, water is rapidly lost under the action of the open channel and the internal lake, and the soil shows a salt return phenomenon.

B. Middle layer soil (60 cm under the surface of the earth sampling)

From the end of 5 months to the beginning of 6 months, the soil salinity value reaches the highest point in each treatment, and the soil salinity accumulation phenomenon is obvious; from the beginning of 6 months to the beginning of 8 months, the salt content of the soil treated by each treatment is in a whole descending trend, and the soil treated by each treatment is in a rainy season desalting state; in the beginning of 8 months to the last ten days of 11 months, the whole treatment shows the trend of increasing firstly and then decreasing, except for the treatment F, the other treatments have the next highest point of the soil salinity, and the soil salinity of the treatment D and the treatment L is respectively 2.5g/kg and 2.2 g/kg. In summary, the movement of the soil and salt in the middle layer of each treatment is obviously influenced by seasonality, and the effect of soil salt accumulation in autumn is weaker than that in spring.

After the rainy season is finished, except for the treatment F, the salinity of the soil treated by the treatment D and the soil treated by the treatment L is uniformly increased in a fixed range. And F, because the earlier-stage plot is arid, and after rainfall supplements water in the later stage, the salt return amount in autumn is higher.

C. Subsoil (sampling 90cm under the surface)

The bottom layer soil is positioned at the lowest layer of the backfilled soil, the layer is slightly interfered by the earth surface and is directly contacted with the leaching-isolating layer or is the shortest distance away from the leaching-isolating layer. From the end of 5 months to the beginning of 6 months, the salinity of the soil after treatment reaches the annual maximum value, and the amount of the soil after treatment D, the amount of the soil after treatment F and the amount of the soil after treatment L are respectively 4.0g/kg, 3.5g/kg and 3.9 g/kg. During the 6-8 month rainy season, each treatment shows a descending trend along with rainfall; after the rainy season is over (after 8 months), the salinity of the soil treated by each treatment is not increased, and the phenomenon of salt accumulation occurs. In general, although the subsoil is buried deeply, the movement law of the salt fraction also exhibits seasonal periodic variation, which is consistent with that observed for the topsoil and the subsoil.

After the leaching isolation layer is arranged, the inhibition effect on soil salt return is not obvious in dry seasons of 5-6 months, but after the soil enters rainy seasons, the reduction range of the salt content of the soil treated by the leaching isolation layer is large, and the leaching isolation layer plays a positive role in soil body desalination. In addition, after the rainy season is over (after 8 months), the leaching prevention layer shows certain capacity of inhibiting salt return of the soil body, and the increase range of the salt content of the soil body is reduced.

In each treatment, the salt content of the soil on the soil body of 0-90 cm is respectively reduced by 20.48-45.45%, and the reduction amplitude is sequentially from large to small, namely F treatment is greater than L treatment and greater than D treatment, so that the salt content of the soil is in a descending trend within the year, the arrangement of the leaching isolation layer has a positive effect on soil body desalination, and the effect of crushing materials is good.

(2) pH value change in soil desalination process

As can be seen from the reference figures 6 to 8, the pH value of the soil treated by each treatment shows a certain regular change along with the increase of the sampling time. Wherein the pH change rule of D processing and L processing is relatively consistent in the soil layers of 0-30 cm, 30-60 cm and 60-90 cm, and the specific expression is as follows: in the 5 to 6 months, the pH value of the soil is stable, and the pH floating ranges of soil layers with different depths (from top to bottom) are 8.31-8.50 and 8.30-8.45 respectively; the pH value of the soil is obviously reduced from 6 months to 8 months; after 8 months, a trend of first significant increase and then decrease was exhibited. F, treating the situation that the pH values of different soil layers generally increase and then continuously decrease along with the sampling time; the above trend is substantially consistent with the soil desalination process.

In conclusion, the results show that: along with the existence of a certain alkali return phenomenon in the soil desalting process, the alkalization action has strong reaction on the surface layer of the soil, but gradually weakens along with the increase of the depth of the soil layer. Even if the pH value is increased at a certain stage, the pH value of the soil can be basically recovered to a normal level along with the time. The use of the leaching isolation layer inhibits the occurrence of alkali return of the soil body in autumn to a certain extent, and the effect of inhibiting alkali return of each treatment is F treatment > L treatment > D treatment. From the observation throughout the year, the pH of each treatment was decreased, and the other treatments were slightly increased after the rainy season than before the rainy season, but the difference was not significant.

The research adopts a common multi-target evaluation method, namely an analytic hierarchy process, to screen the optimal leaching-barrier material, namely the leaching-barrier material with the optimal effect of improving the soil salinity, the pH value and the nutrients. The established multi-target hierarchical analysis results are shown in table 1, wherein the index layer comprises 3 primary indexes of soil property, soil nutrient and material price and 10 secondary indexes of soil pH, soil salinity, organic matters, ammonia nitrogen, available phosphorus, potassium and the like. According to the importance of each index, the weight value of the index is given in combination with the report in the literature. The indexes of soil pH, soil salinity, organic matters, ammonia nitrogen, available phosphorus, potassium, calcium, sodium, magnesium, chloride ions, material price and the like have weighted values respectively as follows: 0.11, 0.21, 0.08, 0.06, 0.10, 0.12, 0.03, 0.05, 0.03, 0.05 and 0.16.

In order to scientifically screen the material of the leaching-barrier layer and eliminate the influence caused by different dimensional dimensions of various indexes, a range standardization method is adopted to carry out standardization processing on data. Table 1 lists soil properties, soil nutrient index data and material costs in each leaching layer treatment; table 2 shows the data obtained by carrying out standard treatment on soil properties, soil nutrient index data and material cost in each leaching layer treatment by a range difference method. The soil property and the soil nutrient value of the soil treated by the leaching isolation layer are higher, the value after standardization is closer to 1, and the material cost is opposite. The normalized data of each process is integrated with the weight of each index and accumulated to obtain the weighted analysis score of each process, which is shown in table 3.

TABLE 1 soil Properties, soil nutrient index data and Material costs in treatment of separate drenching layers

Table 2 soil property, soil nutrient index data and material cost standardized data in each leaching layer treatment

TABLE 3 weighted score table for processing index of each leaching layer

The overall score for the barrier material was between 0.23 and 0.74, with the highest score of 0.74 being treated as F. F is a crushed material area, branches of trees and shrubs are crushed to 1-3cm, blind ditches are normally made after the grooves are opened, the crushed materials are laid at the bottom of the groove, the laying thickness is 40cm, and the earth surface is covered with 1-1.2m of soil. And F, crushing the materials into the optimal leaching layer material from the material saving angle.

Through detection, the landscaping waste crushed material is very difficult to degrade in a saline-alkali soil layer, is not afraid of water bubbles, and can be used for a long time.

Experimental example 2

Example 1 was repeated with the only difference that: blending materials and proportion of the saline soil blender.

Experiments prove that:

the salinized soil improvement formula optimization test takes typical coastal salinized soil of a new ecological city in the Tianjin coastal new area as a test object, four organic wastes are selected, an orthogonal test method is adopted, the coastal salinized soil improvement formula optimization research is carried out at a test base of Tianjin ecological city political landscape Limited company, the four organic wastes are respectively vinegar residue, edible fungus chaff, green branch waste crushed waste and cow dung, the influence on the physicochemical property and the nutrient of the coastal salinized soil is analyzed through a two-year field test, the soil desalting effect, the soil nutrient maintenance and the economic cost of the organic materials are comprehensively evaluated by using a multi-objective evaluation method, and the optimal proportioning of the four organic materials is researched.

Test soil: the soil is collected in a saline-alkali area near a base of an ecological urban administrative landscape company, after withered plant residues on the surface layer are cleaned, deep soil of 0.50m is dug, the soil is clay loam, the volume weight is 1.53g/cm3, the salt content of the low-salt soil is 3.81g/kg, the pH value is 8.69, the salt content of the high-salt soil is 5.23g/kg, and the pH value is 8.91.

Organic materials tested: the decomposed cow dung, the vinegar residue and the edible fungus residue are all sold in the market, and the three organic materials are stacked, fermented and decomposed for half a year in an ecological city experimental area. The greening crushing waste is obtained by crushing branches trimmed in a collecting area of an ecological city, and is subjected to stacking, fermentation and decomposition for one year, and the particle size of the material is about 0.5cm-3 cm. The densities at half-doping time of the four improved material experiments are respectively as follows: cow dung 0.36kg/L, vinegar residue 0.25kg/L, edible fungus 0.32kg/L, and green crushing waste 0.18 kg/L.

Test plants: the seedling species in spring planting are Malus micromalus (4 cm breast diameter) and Lonicera japonica (0.5 m crown diameter), and when planting, cutting off the stem at 1.2 m. Test flower box: the flower box is made of polymer resin, the inner dimension is 0.95m multiplied by 0.64m (length multiplied by width multiplied by height), and two water outlet holes are arranged at the bottom along the diagonal line, and the diameter is about 3 cm.

After the field planting of the nursery stocks is finished, soil is respectively taken from 6 flower boxes, the soil taking depth is 20cm, 1 soil is obtained by mixing by adopting a quartering method, and the weight of each treated sample is about 300 g. After the samples are mixed, the samples are put into a plastic bag and sent to qualified detection units for testing.

TABLE 4 organic materials proportioning Table for soil treatment (Unit: liter)

According to the characteristics of high and low salt content of soil, high salt treatment (code G) and low salt treatment (D) are divided, each treatment is set with contrast and different organic material proportioning treatment, wherein the addition proportion of the decomposed cow dung, the vinegar residue, the edible fungus residue and the greening crushing waste accounts for 15% of the volume of the flower box. Calculate each treatment repeat 6 times for a total of 28 treatments, 168 flower boxes. The specific proportioning scheme is shown in table 1. After the soil is mixed evenly, the mixture is watered thoroughly once, and the malus micromalus and the honeysuckle are planted, wherein 1 plant is planted in each variety, and 2 plants are planted in each flower box. And irrigating for one time every 3d-7d according to the weather conditions in the later period. Other management measures are kept consistent.

The research adopts a common multi-target evaluation method, namely an analytic hierarchy process, to screen the optimal material proportioning combination, namely to screen the material combination with the optimal soil salinity, pH value and nutrient improvement effect and economy. The established multi-objective hierarchical analysis results are shown in table 5, wherein the index layer comprises 3 primary indexes of soil property, soil nutrient and material price, and 6 secondary indexes of soil pH, soil salinity, nitrite nitrogen, ammonia nitrogen, quick-acting potassium, available phosphorus and the like. According to the importance of each index, the weight value of the index is given in combination with the report in the literature. The weight values of indexes such as soil pH, soil salinity, nitrite nitrogen, ammonia nitrogen, quick-acting potassium, available phosphorus, material price and the like are respectively as follows: 0.21, 0.27, 0.08, 0.06, 0.12, 0.10 and 0.16.

In order to scientifically and objectively evaluate soil properties and various indexes of nutrients of different treatment numbers, an average value is taken as a determination characteristic value for soil sampling detection results of multiple times in 2 years of a test, the average value is selected, a method of removing a maximum value, removing a minimum value and summing other results to average is adopted, and therefore adverse effects caused by extreme data are avoided. Meanwhile, in order to further analyze various indexes of different proportioning schemes, the indexes are processed on the same proportioning scheme of the high saline soil and the low saline soil, and a method of adding and averaging is adopted to determine a measured value so as to reduce the influence of soil quality difference of the high saline soil and the low saline soil.

In order to scientifically screen a material proportioning scheme and eliminate the influence caused by different dimensions of various indexes, a range standardization method is adopted to carry out standardization processing on data. Table 4-2 lists soil properties, soil nutrient index data, and material costs for each soil treatment; tables 4-3 list data obtained after standard treatment of soil properties, soil nutrient index data and material cost in each soil treatment by the range method. The higher the values of soil ammonia nitrogen, quick-acting potassium and available phosphorus nutrients of the material treatment soil are, the closer the value is to 1 after the soil is standardized, and the opposite is realized on the soil total salt content, the PH value, the nitrite nitrogen and the material cost. The improvement of the coastal saline soil needs to reduce salt and inhibit alkali, and meanwhile, nitrite is considered to be a product of denitrification in the soil, and the excess is toxic to plant growth and soil organisms, so that the smaller the selection is, the better the improvement is. The specific normalized data was calculated using the following formula.

In the formula: n represents a normalized value, X represents a measured value of the index, Xmin represents a measured value of the index, and Xmax represents a measured value of the index.

Table 5 hierarchical analysis structure for material combination optimization screening

Target layer of Target layer	Index layer	Secondary index layer Sub index layer
			Ideal material	Soil Properties	Soil pH Soil pH
		Soil salinity Soil salt
				Soil nutrient Soil nutrients	Nitrite nitrogen Nitrite Nitrogen
		Ammonia nitrogen
					Quick-acting potassium Available potassium
		Available phosphorus Available phosphorus
				Material price	—

The normalized data of each process is integrated with the weight of each index and accumulated to obtain the weighted analysis score of each process, which is shown in table 7.

TABLE 6 soil Properties, soil nutrient index data and Material costs in various soil treatments

Soil Total salt and soil pH analysis

As can be seen from FIG. 13, the average total salt content of each treatment is in the range of 1.22-3.38g/kg, and the salt content of each treatment soil is as follows from small to large: 3< CK4< CK2<1<6< CK5<7<2<4<9<5< CK3< CK1< 8. The lower total salt content was found in treatment 3(1.22), treatment CK4(1.35) and treatment CK2 (1.53). In summary, the application of the crushed material, the vinegar residue or the mixture of the vinegar residue and the crushed material in high proportion in each treatment shows better effect on reducing the salt content of the soil. This may be due to the addition of the crushed material, which improves the texture of the soil, increases the permeability of the soil, facilitates the dissolution of salt and the leaching out of the tank with the downward migration of water.

The pH value of each treatment is in the range of 7.36-8.47, and the pH value of each soil treatment is as follows from small to big: CK2<5<4<3<7<2< CK4< CK3< CK1<8<1< CK5<6<9, and treatments CK2(7.36), treatment 5(7.74), and treatment 4(7.83) were found at lower pH values. In summary, after applying cow dung, vinegar residue, edible fungus residues and greening crushed waste materials along with soil alkali return in the soil desalting process, the soil alkali return phenomenon is not actually controlled, but the pH value is directly 6.5-8.5 at present and is an acceptable value.

TABLE 7 soil Properties, soil nutrient index data and Material cost standardization data in various soil treatments

As can be seen from the standardized data of various indexes of the soil, the comprehensive score of the material combination is between 0.34 and 0.65, the difference between different treatments is obvious, and except for treatments 8, 6 and 9, the evaluation values of the other treatments are higher than that of a blank control CK 5. The organic materials can improve the physicochemical property of the coastal saline soil and increase the soil nutrient and organic matters.

The processing with the highest score of 0.65 is CK4, the components of the processing are 90 liters of green crushed waste and 510 liters of saline soil, the processing is 7, the comprehensive score is 0.62, and the components of the processing 7 comprise 45 liters of cow dung, 15 liters of vinegar residue, 45 liters of edible fungus chaff, 30 liters of green crushed waste and 510 liters of saline soil. And the third step is treatment 5, the comprehensive score is 0.60, and the composition of G5 comprises 30 liters of cow dung, 30 liters of vinegar residue, 45 liters of edible fungus chaff, 15 liters of greening crushing waste and 510 liters of saline soil. The comprehensive scores between treatments are ordered as: CK4>7>5>3> CK3> CK2>2>1>4 ═ CK1> CK5>9>6> 8. Therefore, the optimal proportioning scheme for multi-objective evaluation is to apply the green and crushed waste singly.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. Not all embodiments are exhaustive. All obvious changes and modifications which are obvious to the technical scheme of the utility model are covered by the protection scope of the utility model.

Claims (9)

1. The coastal saline-alkali land greening system based on garden greening waste utilization is characterized by comprising a covering layer, a soil layer to be improved, a permeable membrane layer, a leaching layer, a concealed pipe salt drain ditch, a salt drain well, an air vent, a waterproof layer and a saline-alkali soil layer which are sequentially arranged from top to bottom;

the covering layer is arranged on the ground surface near the root of the soil plant;

the soil layer to be improved is original saline soil;

the leaching isolation layer is made of crushed garden branch, trunk or tree root waste;

the concealed pipe salt discharge ditch is positioned below the leaching layer and protrudes into a groove of a saline-alkali soil layer, and a concealed pipe is arranged in the groove;

the slope direction of the concealed pipe is connected with a communicated salt discharge well;

the vent hole extends downwards from the soil layer to be improved to the permeable membrane layer;

the salt discharge wells are arranged in the soil body at intervals, the depth of the salt discharge wells extends into the saline-alkali soil layer from top to bottom, and the salt discharge wells are communicated with a municipal drainage system, a landscape water body or rivers and lakes through drainage pipes.

2. The coastal saline-alkali soil greening system of claim 1, wherein: the covering layer is made of crushed materials of leaves, dried barks or branches, and the covering thickness is 0.5-20 cm.

3. The coastal saline-alkali soil greening system of claim 1, wherein: the permeable film layer is a permeable non-woven fabric.

4. The coastal saline-alkali soil greening system of claim 1, wherein: the sprinkling layer is made of landscaping waste crushed materials, the thickness of the sprinkling layer is 20-50cm, and the particle size of the landscaping waste crushed materials is 0.5-3 cm.

5. The coastal saline-alkali soil greening system of claim 1, wherein: the drain pipe is a PVC seepage pipe; a plurality of rows of narrow-strip-shaped water seepage holes can be formed on the circumference; the outlet of the drainage pipe leads to a municipal drainage well, and the central elevation of the drainage pipe is not lower than the top of the water separation layer.

6. The coastal saline-alkali soil greening system of claim 1, wherein: the salt discharge ditches are arranged on the upper layer of the saline-alkali soil at intervals, the arrangement interval is 6-8 meters, the width and the depth are 25-45cm, and the lower surface is provided with a groove protruding into the saline-alkali soil layer.

7. The coastal saline-alkali soil greening system of claim 1, wherein: the concealed pipes are arranged at intervals of 7-9 meters, are PVC (polyvinyl chloride) seepage pipes and are externally coated with permeable geotextile.

8. The coastal saline-alkali soil greening system of claim 1, wherein: a waterproof layer is arranged between the leaching layer and the saline-alkali soil layer.

9. The coastal saline-alkali soil greening system of claim 1, wherein: and a lateral waterproof layer is adopted for reverse wrapping at the joint of the greening system and the surrounding buildings or structures.

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