Soil improvement and saline-alkali water spray irrigation method suitable for saline-alkali beach

Abstract

The invention provides a soil improvement and saline-alkali water spray irrigation method suitable for a saline-alkali beach. The method comprises the following steps: reclamation and field building, dike building and tide blocking: building and enclosing a mud flat area needing reclamation and planting in the earlier stage to prevent further erosion of saline-alkali water; constructing water guide systems such as a reservoir and a drainage ditch; after the soil is slightly aired, turning over and loosening the soil in the beach area, doping desulfurized gypsum (calcium sulfate), charcoal and a high-molecular water-retaining material into the soil, and fully mixing and uniformly stirring to form a water-retaining layer and provide nutrition for vegetation; sowing the seeds in a planting area according to the density requirement; finally, spraying a layer of macromolecular binding material on the surface to prevent weathering and saline-alkaline water erosion and slow down migration of salt to the planting layer; during irrigation, red soil is poured into the reservoir, saline-alkali water is introduced for stirring and standing for a period of time, then mixed muddy water is used for irrigation, and sprinkling irrigation is adopted for irrigation so as to slow salt infiltration into the earth surface; when the rainfall period is up, rainwater can be used for watering and washing off salt crystals on the earth surface. According to the method, rich mud flat resources in China are fully developed and utilized, the saline-alkali water serves as an irrigation water source, the problems of complex water diversion, troublesome salt leaching, fresh water deficiency, too high cost and the like of a traditional method are solved, the land utilization benefit and the agricultural production level are greatly improved, and the influence of salt on plants is relieved; the restoration of the ecological environment and the improvement of the agricultural production level are promoted.

Description

Technical Field

[0001] The invention relates to the field of agricultural production, and in particular to a soil improvement method suitable for saline-alkali tidal flats and a saline-alkali water spray irrigation method thereof. Background Art

[0002] Tidal flats are a general term for beaches, river beaches and lake beaches. They refer to the tidal zone between the high tide and low tide of coastal tides, the beaches between the normal water level and flood level of rivers and lakes, the beaches below the flood level of seasonal lakes and rivers, and the beach area between the normal water level and the maximum flood level of reservoirs and ponds. In China, tidal flats are mainly distributed in inland river basins, northwestern basins and depressions, and most coastal seashores, with a total area of ​​2.1704 million hectares. Tidal flats are an important reserve land resource in China, with the characteristics of large area, concentrated distribution, good location conditions, and great potential for comprehensive development of agriculture, animal husbandry and fishery.

[0003] In recent years, due to various large-scale construction projects, a large amount of arable land has been developed and occupied, the area of ​​arable land has continued to decrease, and the quality of arable land has declined year by year. If we continue to reclaim mountains and plains, it will not only cause serious consequences such as soil erosion and ecological damage, but also cause a waste of freshwater resources. Therefore, in order to improve ecological and economic benefits and achieve sustainable development, it is very important to effectively and rationally utilize tidal flat resources to reclaim arable land. If we can rationally develop and utilize tidal flat resources for the planting of crops and cash crops, it can not only drive the economic development of tidal flat areas, but also protect the ecological environment and species diversity of tidal flat areas.

[0004] At present, there are many difficulties in reclaiming and utilizing tidal flat resources for planting. Coastal mudflats are constantly washed by seawater. Therefore, the salt retention brought by seawater leads to high salt content, low nutrient content, poor physical structure and hindering plant growth. Inland saline-alkali tidal flats are mostly distributed in deserts and Gobi areas. These areas are generally dry and rainy, with obvious evaporation. Salt can easily accumulate on the soil surface under capillary water pressure and evaporation, affecting plant growth. If these saline-alkali tidal flats are to be reclaimed and utilized, on the one hand, it is necessary to improve the physical structure of the soil and increase soil nutrients, which will greatly increase the cost of fertilization; on the other hand, the salt in these saline-alkali lands will gradually accumulate, making salinization and secondary salinization very likely to occur. If plants are to grow, the traditional method is to use fresh water to wash the salt from the land. In the southeastern coastal areas, the economy is developed and the population is large, and a large amount of water resources are used for urban and industrial water. In the inland northwest areas, rainfall is scarce and fresh water resources are extremely precious. At the same time, fresh water can also wash away trace elements such as phosphorus, iron, manganese and zinc in the soil. Therefore, using fresh water to wash salt will cause a large amount of fresh water resources to be wasted. The diversion and transportation of fresh water resources will also greatly increase the cost of planting, and soil fertility will also decrease. This method is not only costly but also inefficient.

[0005] In summary, the rational development and utilization of saline-alkali tidal flat resources will help improve the quality of arable land and food production, thereby alleviating the contradiction between economic and social development and the shortage of arable land; it will also help improve the local ecological environment and realize the protection and utilization of water and soil resources; efficient reclamation and utilization of saline-alkali tidal flats must solve two important problems: soil improvement and irrigation water.

[0006] The present invention proposes a soil improvement method suitable for saline-alkali tidal flats and a saline-alkali water sprinkler irrigation method, aiming at rationally developing and utilizing tidal flat resources in saline-alkali areas of my country, reducing the financial and time costs of ecological restoration in tidal flats, slowing down salt migration, reducing soil salinity, improving soil fertility, and improving land productivity. In the reclamation and planting of tidal flats, there are the following difficulties: (1) After reclamation, the salt content of groundwater in the tidal flats is high, and the soil is separated from the saline-alkali water environment, and the surface water evaporates vigorously, resulting in salt accumulation and increased soil salinity. Therefore, in the process of tidal flat development and utilization, the most important thing is to slow down the salt migration of the soil and reduce the salinity of the soil; (2) Generally speaking, tidal flat restoration areas are mostly muddy or sandy tidal flats, with poor soil structure, less aggregate structure, poor adhesion, easy to be eroded and washed away, good water permeability, weak soil fertilizer and water retention capacity, and relatively scarce nutrients such as organic matter, quick-acting nitrogen and quick-acting phosphorus in the soil. Therefore, in the process of tidal flat ecological restoration, the soil is not easy to be eroded and washed away. During reclamation, special attention should be paid to increasing fertilizer and conserving water to improve soil quality; (3) The traditional method of reclamation of tidal flats is to wash the salt from the soil with fresh water. However, there is a serious shortage of fresh water resources in coastal areas and the northwest inland, while seawater resources are inexhaustible in coastal tidal flats. There are a large number of saltwater lakes and saline-alkali beaches in the northwest. These are all saline-alkali water. If saline-alkali water can be used for irrigation, a lot of financial resources can be saved. However, saline-alkali water is generally alkaline and contains a lot of salt. It is not suitable for direct land irrigation. Therefore, when using saline-alkali water for agricultural irrigation, it is necessary to solve the negative effects of water on the soil and reduce the salinity of water. The rational use of saline-alkali water for irrigation is the key technology for agricultural production in tidal flats. Summary of the invention

[0007] The purpose of the present invention is to provide a soil improvement method suitable for saline-alkali tidal flats and a saline-alkali water sprinkler irrigation method. By constructing water storage and appropriate drainage channels, using desulfurized gypsum, biochar and polymer water retaining agent to add fertilizer and water retention to the planting layer, using polymer adhesive as the surface bonding layer, and finally using saline-alkali cement slurry treated with acid red soil for irrigation, the development and utilization of the tidal flat area is realized, and a complete tidal flat agricultural production system is established.

[0008] A soil improvement method suitable for saline-alkali tidal flats and a saline-alkali water sprinkler irrigation method, comprising the following steps:

[0009] Reclamation of land, building of embankments to prevent tides;

[0010] construction of reservoirs and drainage ditches;

[0011] Plow the land and mix materials such as gypsum, biochar and polymer water retaining agent to form a planting layer;

[0012] sowing plant seeds;

[0013] Spray a polymer adhesive on the surface to form a protective layer;

[0014] During the later irrigation, take saline water nearby as irrigation water, mix the saline water and acidic red soil, let it stand for a while, and then carry out sprinkler irrigation.

[0015] Reclamation and embankment construction, mechanical tillage, and land leveling, the specific contents include:

[0016] By building a solid dam, it is possible to effectively prevent tides, storm surges, waves and other seawater from eroding the tidal flats, which helps to protect the reclaimed land from the effects of seawater erosion and maintain the stability of the land. By rationally designing the structure of the dam, the drainage effect can be achieved, rainwater or groundwater in the tidal flats can be discharged, and the appropriate humidity of the land can be maintained. Leveling the land is an important measure to improve the hazards of salinization. It is not only conducive to improving irrigation and drainage, but also can promote the uniform infiltration of water, avoid salt accumulation due to high and low unevenness, and significantly improve the effect of rainfall salting and irrigation salt washing. It is recommended to carry out 30~40 cm mechanical deep plowing for the newly reclaimed land on the tidal flats, and then level the land. The height difference should not exceed 3 cm. First, dry land leveling, and then shallow leveling.

[0017] Build water storage and drainage systems to strictly control water use and drainage in the reclamation area. Specific contents include:

[0018] Dig rivers in the reclamation area, and build gates at the estuary and salt lake to prevent saline water from flowing back, so as to remove the large amount of salt in the rainy season and the newly reclaimed land. Build irrigation and water diversion canals, establish corresponding drainage systems to remove salt, and dig interception ditches inside the reclamation area to prevent seawater or saline water from continuing to replenish salt to the reclamation area. Or dig drainage ditches in the fields to form strip fields and build weirs on the strip fields, use rainfall to store fresh water and irrigate salt. After a rainy season, the desalination rate of 1m soil layer can reach 10-30%. Build reservoirs in low-lying places near the sea and lakes to prevent saline water from infiltrating the reclamation area. When the rainfall is sufficient, a certain amount of fresh water can be stored. The fresh water from the rainfall can be used to irrigate the reclamation area, and it also has the effect of washing salt; when the climate is dry and the rainfall is less, the reservoir can be used to treat saline water for spray irrigation of the reclamation area.

[0019] Mixing gypsum, biochar and polymer water retaining agent in the planting layer can achieve the effect of increasing fertilizer and retaining water. The specific contents include:

[0020] Desulfurized gypsum is a product of flue gas desulfurization produced during coal combustion in thermal power plants. Desulfurized gypsum can significantly increase the Ca content of saline-alkali land. 2+and SO4 2− Concentration. Ca in desulfurized gypsum 2+ Can replace Na in saline-alkali soil + , converting toxic compounds of sodium carbonate and sodium bicarbonate into less toxic neutral salts of sodium sulfate. Therefore, the use of desulfurized gypsum can provide the soil with essential nutrients such as calcium and sulfur; increase soil aggregate stability, electrical conductivity, soil water retention capacity and porosity; and promote the improvement of acidic and alkaline soils.

[0021] Biochar is a carbon-rich, porous, stable polycyclic aromatic hydrocarbon product formed by high-temperature pyrolysis of biomass organic matter such as straw and bamboo under anaerobic or anoxic conditions below 700°C. The use of biochar can effectively improve the physical, chemical and biological properties of saline-alkali soil; increase soil porosity and field water retention capacity; increase soil calcium content; increase the effectiveness of nutrients such as nitrogen, phosphorus and potassium to plants; increase the survival rate of microorganisms and improve the growth environment of plants; biochar can also directly increase the organic carbon content in the soil and promote cation exchange, thereby stabilizing the soil structure; the higher level of water-soluble potassium in biochar is also considered to be one of the most important potential mechanisms for biochar to promote the growth of plants affected by salinity.

[0022] The composite polymer water-retaining material used in the present invention is mainly composed of sodium polyacrylate, which is white particles under dry conditions and is transparent hydrogel after being saturated with water. It can be slowly degraded under natural conditions, and the degradation period is 36 months. The final products are CO2 and H2O, which are non-toxic and harmless. The composite polymer water-retaining material has excellent water absorption and water release capabilities. In the rainy season, the water absorption of the material can effectively reduce the moisture content of the soil and reduce the decay and death of the plant roots caused by excessive immersion. In the dry season, the water release of the material can supply water to the vegetation. In the process of absorbing and releasing water, the swelling and shrinking of the material itself can further improve the structure of the soil, which is conducive to the growth of vegetation. The use of water-retaining agents can reduce the evaporation and leakage of water, improve the air permeability and agglomeration of the soil, and slow down the migration of salt, thereby reducing the salinity of the soil.

[0023] After sowing the seeds, spray a layer of adhesive on the surface, the main contents are:

[0024] The composite polymer adhesive material used in the present invention is mainly composed of modified polyvinyl acetate, which can be slowly degraded under natural conditions, with a degradation period of 24 months, and the final product is CO2 and H2O, which is non-toxic and harmless. This composite polymer adhesive material mainly improves the aggregate content of the soil, enhances the physical and mechanical properties of the soil such as anti-disintegration and shearing ability, improves the compaction degree of the soil and the anti-scouring ability under heavy rain conditions, and reduces the erosion degree of the soil by wind and saline-alkali water. Since the present invention adopts the method of sprinkler irrigation, water will slowly infiltrate into the planting layer on the surface of the adhesive layer, and part of the salt will remain on the surface. When it is rainy season, rainfall or artificial irrigation and salt washing will wash away the salt crystals on the surface of the adhesive layer and discharge them through the drainage system.

[0025] Finally, the muddy water mixed with saline water and acidic red soil near the planting area is used for irrigation during the plant development period. The specific contents include:

[0026] Soil in saline-alkali tidal flats is generally alkaline, and due to long-term saltwater erosion, soil is relatively lacking in nutrients such as nitrogen, phosphorus, potassium, and iron. Red soil is generally acidic, and contains minerals and organic matter such as potassium and iron, which is very suitable for improving the soil environment of saline-alkali land. In addition, red soil is mainly distributed in low mountain and hilly areas south of the Yangtze River and areas such as Gansu and Qinghai in the northwest of China, and is rich in resources and convenient to obtain materials. Tidal flats are seriously lacking in freshwater resources, and the adjacent seawater and saltwater resources are inexhaustible. Therefore, the present invention considers that the muddy water after the saline-alkali water and red soil are mixed is used to irrigate the tidal flat planting land, and the irrigation method is sprinkler irrigation. Most of the salt produced during sprinkler irrigation will be precipitated in the bonding layer, and when it rains locally, rainwater will be able to wash the salt into the drainage ditch and then discharge the field. In the long run, a balanced ecosystem can be established, thereby realizing the transformation and utilization of the tidal flat area and ecological restoration.

[0027] The present invention utilizes a variety of materials to improve the saline-alkali soil in the tidal flats, and utilizes saline-alkali water for irrigation, thereby achieving ecological restoration of the tidal flats. The present method has many advantages:

[0028] Build embankments to prevent moisture, construct drainage systems, strictly control the moisture in the fields, prevent further erosion of the soil by saline-alkali water, and achieve the purpose of reclaiming land; use desulfurized gypsum to provide the soil with essential nutrients such as calcium and sulfur, improve soil structure, and form a stable planting soil layer; add biochar to increase the organic matter content of saline-alkali soil, increase the effective nitrogen, phosphorus, potassium and other nutrients and cation exchange capacity in the soil; use high molecular weight water retaining agents to improve soil structure, reduce soil permeability, thereby reducing the erosion of saline-alkali water on the fields and improving soil water retention. , reducing water evaporation and thus slowing down the migration of salt; the use of polymer adhesives further enhances the soil's water retention capacity, greatly reducing the erosion of saline-alkali water and wind on the soil, while nutrients are not easily lost, and salt is not easy to penetrate into the deep soil, making it convenient to wash salt; using the widely distributed red soil in my country can neutralize the alkalinity of saline-alkali water and provide some nutrients and organic matter for plants; the water resources of seawater and saltwater lakes are inexhaustible, and it is very convenient to obtain materials and irrigate, which can greatly save freshwater resources in coastal and northwestern regions, and save financial and human resources. The present invention provides a complete ecological restoration plan for saline-alkali tidal flats, which can be widely developed and utilized in tidal flats, increase agricultural land or improve the local ecological environment, thereby achieving ecological restoration in tidal flats.

[0029] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0030] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the process of soil improvement and saline-alkali water sprinkler irrigation in saline-alkali tidal flat areas (ecological restoration process diagram) according to an embodiment of the present invention.

[0032] Figure 2 It is a construction schematic diagram of the development and utilization of saline-alkali tidal flat areas according to an embodiment of the present invention.

[0033] Figure 3It is a detailed rendering (repair rendering) of soil improvement in saline-alkali tidal flat areas according to an embodiment of the present invention.

Claims

1. A soil improvement method for saline-alkali tidal flats and a saline-alkali water sprinkler irrigation method, comprising the following steps: Reclamation of land, building of embankments to prevent tides; construction of reservoirs and drainage ditches; Plow the land and mix the developed mixed soil conditioner into the soil to form a planting layer; sowing plant seeds; Spray a polymer adhesive on the surface to form a protective layer; During the later irrigation, saline water is taken from nearby as irrigation water, the saline water and acidic red soil are mixed and stirred and left to stand for a certain period of time before spray irrigation is carried out.

2. According to the soil improvement and saline-alkali water sprinkler irrigation method suitable for saline-alkali tidal flats described in claim 1, its innovative contents lie in four aspects: using desulfurized gypsum, biochar and polymer water retaining agent as soil improvers can greatly improve the physical structure and nutrients of the soil; using polymer adhesives to enhance soil water retention, reduce water evaporation and slow down salt migration; using mixed mud water of red soil and saline-alkali water as irrigation water, the acidic red soil can provide some nutrients to the saline-alkali water and reduce the pH value of the saline-alkali water; the irrigation method adopts sprinkler irrigation, so that water can slowly penetrate into the planting layer, and the salt will be partially crystallized and retained in the protective layer. When the rainy period comes, the salt will be washed out of the planting area by rainwater.

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