Method for transforming viscous heavy saline soil by constructing side salt leaching channel

Abstract

The invention relates to a method for transforming viscous heavy saline soil by constructing a side salt leaching channel, which comprises the following steps of: selecting the viscous heavy saline soil in southern Xinjiang, communicating an alkali removal channel network through dredging, and constructing a high-ridge border field; a ditcher divides a whole field into parallel strip-shaped soil bodies perpendicular to a drainage channel, independent units of strip-shaped soil bodies, deep ditches and strip-shaped soil body alternated side salt leaching are built, concealed pipes and gravel materials are arranged, the gravel ditches, the concealed pipes and alkali drainage ditches are communicated, and side salt leaching channels of the field size are built; performing drip irrigation and high-density planting of halophilic plants to cover salt inhibition, and performing deep plowing and returning to the field when the salt absorption amount is maximum; through biological salt absorption, field returning, field soaking in slack season water, retting and field piece side salt leaching circulation, soil salt and plant salt are rapidly and laterally washed, the soil structure is improved, the soil biological fertility is created, pioneer crops can be planted after 2-3 years, and a new way is provided for increasing new cultivated land, fixing civil safety, improving the living environment and promoting local agricultural development.

Description

Technical Field

[0001] The invention discloses a method for rapidly improving clayey and heavy saline soil in arid areas, specifically a method for rapidly transforming clayey saline soil into farmland by constructing a field side salt washing channel and combining the return of functional halophytes to the field to gradually improve soil biological fertility, belonging to the field of engineering biological soil improvement. Background Art

[0002] The fine soil plain in front of the mountains in southern Xinjiang is mostly interlayered with silt and clay due to the weathering of parent materials along with snowmelt and mountain precipitation. The thickness of clay is more than 4m. In addition, the weathering of salt rock makes the parent materials of soil naturally salty, which makes the land salinized and the structural permeability is extremely poor. The Hongqi Farm of the Third Division is a distribution area of ​​clayey and heavy saline soil. There is little arable land. Affected by the salinity and structure of the soil, there are few varieties of crops suitable for it and the yield is low. The local area has been improving the soil with heavy clay, heavy salt and low productivity for 20 to 30 years through large water pressure salt. Due to the deep clay layer, the irrigation water infiltration is slow and it is difficult to reach the underground pipes, so the underground pipe drainage project cannot produce the function of drainage and salt washing in this land. Six years after the implementation of the local underground pipe drainage project, it was abandoned again. In recent years, due to the poor soil quality and heavy salinity, the local agricultural income is low, the agricultural population is outflowing, the economic development is difficult, and the phenomenon of poor ecological environment is becoming more and more serious. Therefore, simply washing salt cannot improve the heavy saline soil, and the local area is in urgent need of a sustainable and effective soil improvement method.

[0003] Clay soil with deep soil layers needs to be transformed by adding organic materials to improve the problems of impermeability, airtightness and low biological fertility. The cost of purchasing, transporting and landfilling organic materials is too high, and farmers find it difficult to accept the feasibility of large-scale soil improvement.

[0004] Only true halophytes can grow in soil with salt content above 4%, mainly halophilic plants, also known as salt-absorbing plants. Due to the high salt content in their bodies (20%-50%), they need to be mowed and removed to reduce the salinity of the soil, and cannot be returned to the fields.

[0005] The rainfall in southern Xinjiang is generally around 50 mm, and agricultural water is reservoir water with low mineralization (around 2g / l). In addition, groundwater exploitation is prohibited and fresh water is extremely scarce, so it is impossible to pump salty water into fresh water.

[0006] In response to the above problems, based on the traditional practice of soaking fields to wash salt, using underground pipes to drain and wash salt, and using drip irrigation to plant halophytes to mow and remove salt for many years, the research team combined local conventional measures and, based on winter and spring irrigation practices, carried out transformation practices of underground pipes + gravel ditches + drip irrigation to plant absorbing plants + returning salt-absorbing plants to the fields + soaking fields to ferment organic matter and side-washing salt. A soil improvement model suitable for local soils with rapid results was proposed: halophilic plants were selected to absorb salt and return it to the fields for saturated fermentation, and side-washing salt channels were provided in the fields to rapidly transform clayey and heavy saline soils on a large scale. In arid areas, a method of returning salt-absorbing plants to the fields and washing salt sideways on clayey and heavy saline soils to build new arable land was established, providing a new way to increase new arable land, secure the borders, improve the living environment, and promote local agricultural development. Summary of the invention

[0007] The present invention aims to provide a method for constructing a side-washing salt channel to transform heavy saline soil. The method selects heavy saline soil in southern Xinjiang, dredges and connects the drainage canal network, builds high-ridged fields, and uses a ditching machine to divide the entire field into parallel strip soil bodies with vertical drainage canals, and builds independent units of side-washing salt with strip soil bodies-deep ditches-strip soil bodies alternating, and lays concealed pipes and gravel materials, connects gravel ditches-concealed pipes-drainage ditches, and constructs a side-washing salt channel on the scale of a field; drip irrigation is used to plant halophilic plants at a high density to cover and inhibit salt, and deep plowing and returning the fields when the salt absorption is the largest; through biological salt absorption, returning to the fields, soaking the fields with water during the slack season, fermentation and field side-washing salt circulation, not only soil salt and plant salt are quickly side-washed, but also soil structure is improved and soil biological fertility is created, and pioneer crops can be planted after 2-3 years, which provides a new way to increase new arable land, secure the border, improve the living environment, and promote local agricultural development.

[0008] The method for constructing a side-washing salt channel to transform heavy saline soil according to the present invention is carried out according to the following steps: Plot selection: a. In the autumn rest period, choose heavy saline soil with a salt content of 5-7%, level the land, and plan it into a ridge field with a length of 300m and a width of 100m, with a ridge height of 50cm and a width of 40cm; Side wash salt channel construction: b. Use a single-chain rotary furrow opener with a 15cm blade on the chain, pulled by a 50-horsepower agricultural machine, and open parallel furrows vertical to the drainage canal. The furrows are 1.2m deep, 30cm wide, and 6m apart. The entire field is divided into parallel strips of soil vertical to the drainage canal through 1.2m deep furrows, and an independent unit for side-washing salt is built with strips of soil, deep furrows, and strips of soil alternating between them. Prefabricated concealed pipe: c. Drill 60 holes / m with a hole diameter of 5mm on the upper surface of the PVC pipe, then wrap the PVC pipe with a layer of permeable geotextile. The geotextile and gravel layer serve as the outer filter layer, and install a ball valve at the outlet of the tail end of the PVC pipe; d. After the trenching in step b, a layer of permeable geotextile is laid from bottom to top, and 15 cm of gravel with a particle size of 2 cm is filled. The PVC pipe in step c with a diameter of 125 mm is laid on the gravel, with the perforated surface facing upward. The PVC pipe is inclined toward the alkali drainage channel with a gradient of 1 / 600-700. The PVC pipe is covered with 15 cm deep gravel, permeable geotextile, 60 cm of sand and gravel and 30 cm of river sand to form a field gravel ditch containing a concealed pipe, which is a field side salt washing channel leading to the alkali drainage channel. Then the land is leveled, 20 cm of topsoil is mixed with sand, 2000 kg of decomposed cattle and sheep manure, 500 kg of superphosphate and 20 kg of urea are applied per mu, and the soil is turned over and harrowed evenly to make full use of the slack water for winter irrigation of 200-600 m 3 / mu salt washing; repair the drainage ditch, the ditch depth is 3 meters, and connect the irrigation area drainage channel network; Planting of salt absorbing plants: e. The following year, after the land in step d is rotary tilled and suppressed, the saltwort seeds and river sand are evenly mixed in half, and the seeder completes the digging of shallow furrows, laying of drip irrigation belts, and sowing at one time; dripping water immediately after sowing, and the wet peak is determined to be the top of the furrow; dripping water once every 2 days in the morning, and the furrow is determined to be free of water; after 15 days, watering is carried out when it is dry and wet; 10-20kg / mu of urea is applied with water drops after the seedlings are 10cm tall, and drip application is carried out 4 times during the growth period; Return the whole plant to the field: f. In autumn, when the biomass of the Salicornia herba in step e is the largest, crush the stalks with a stalk beater, spread 20 kg urea / mu, and then deep plow the field and flood the field with canal water at 200-400 m 3 / mu, wash the salt and ferment the soil organic matter; continue to plant the salt-absorbing plant Salicornia herba the following year, repeat steps e and f to wash the salt sideways, transform the heavy saline soil structure, plant pioneer crops after 2-3 years and create new arable land.

[0009] The method for constructing a side-washing salt channel to transform heavy saline soil of the present invention is characterized by: High ridges on the ridges are conducive to washing salt and alkali from the fields for many years in arid areas; concealed pipes and sand and gravel connected to the drainage ditch are conducive to rapid side washing of salt and physical improvement of the structure of heavy clay saline soil; high-density planting of highly salt-tolerant true halophytes is conducive to increasing coverage, reducing evaporation and salt accumulation in bare land, and maximizing salt absorption and carbon fixation; salt-absorbing plants are returned to the fields for soaking in water and gravel ditches to achieve composting of soil organic matter, rapid side washing of soil and plant salts, and enter the drainage ditch for a large water-salt cycle, completing rapid side washing of salt and soil improvement on the field scale of heavy clay saline soil; 2-3 years after planting salt-absorbing plants, soil biological fertility can be quickly built up, and then pioneer crops can be planted, thus creating new farmland.

[0010] By mechanically building high-ridged fields, trenches are dug at intervals in the direction of the drainage ditches in the fields to bury concealed pipes and drainage filter materials, and the water used for soaking the fields and drip irrigation during the growing season are used to drain water and salt from the arable layer laterally. Mechanized shallow trenches are dug for drip irrigation to plant salt-absorbing plants, strengthen water and fertilizer management, and maximize biomass. In autumn, after the whole plant is crushed, nitrogen fertilizer is spread and deep plowing is carried out. In winter, irrigation is carried out and the field is fermented with saturated water to quickly wash the soil and plant salts laterally and drain them from the arable layer to create new arable land.

[0011] In view of the chain problems of heavy soil, deep clay layer, high salt content in saline soil, extremely difficult agricultural production and poor ecological environment, we chose the heavy saline soil in southern Xinjiang, dredged and connected the drainage channel network, built high ridges and fields, and used trenchers to divide the entire field into parallel strips of soil with vertical drainage channels, and built independent units of side-washing salt with strips of soil, deep ditches and strips of soil alternating. We laid underground pipes and gravel materials, connected the gravel ditches, underground pipes and drainage ditches, and constructed field-scale side-washing salt channels; drip irrigation was used to plant halophilic plants at a high density to cover and inhibit salt, and deep plowing and returning the fields when the salt absorption was the largest; through biological salt absorption, returning to the fields, soaking the fields with water during the slack season, fermentation and field side-washing salt circulation, we can not only quickly side-wash soil salt and plant salt, but also improve soil structure and create soil biological fertility. Pioneer crops can be planted in 2-3 years, providing a new way to increase new arable land, secure the border, improve the living environment and promote local agricultural development. DETAILED DESCRIPTION

[0012] The total planting area is 200 mu, which is clay and heavy saline soil farmland that has been abandoned for many years. The irrigation water in the planting area mainly comes from mountain reservoirs. Due to the weathering of salt rocks, the mineralization of reservoir water is high, 1-3g / L; Phragmites australis was planted in 2023, but it did not survive; in 2024, the method described in the present invention is used to demonstrate the planting of 200 mu of salt-land Suaeda salsa, achieving the effect of increasing carbon, washing salt, improving soil, and being able to plant crops. Example 1

[0013] In 2024, the method of constructing a side-washing salt channel to transform heavy saline soil was tested in the first company of Hongqi Farm, the third agricultural division; Plot selection: a. In the autumn rest period, choose heavy saline soil with a salt content of 7%, level the land, and plan it into a ridge field with a length of 300m and a width of 100m, with a ridge height of 50cm and a width of 40cm; Side wash salt channel construction: b. Use a single-chain rotary furrow opener with a 15cm blade on the chain and a 100-horsepower agricultural machine to pull it. If necessary, modify and replace the furrow opener accessories according to local conditions. Drill parallel furrows vertically along the drainage canal with a depth of 1.2m, a width of 30cm and a spacing of 6m. Adjust the tractor's traction hydraulic device and travel speed to control the furrow depth and width. Divide the entire field into parallel strips of soil vertically along the drainage canal through a 1.2-meter deep furrow, and build an independent unit for side-washing salt with strips of soil, deep furrows and strips of soil alternating between them. Prefabricated concealed pipe: c. Drill 60 holes / m with a hole diameter of 5mm on the upper surface of the PVC pipe, then wrap the PVC pipe with a layer of permeable geotextile. The geotextile and gravel layer serve as the outer filter layer, and install a ball valve at the outlet of the tail end of the PVC pipe; d. After the trenching in step b, lay a layer of permeable geotextile from bottom to top, fill with 15cm gravel with a particle size of about 1.5cm, lay the PVC pipe in step c with a diameter of 125mm on the gravel, with the perforated surface facing up, and the PVC pipe is inclined to the alkali drainage channel with a gradient of 1 / 600. Cover the PVC pipe with 15cm deep gravel, permeable geotextile, 60cm of sand and gravel and 30cm of river sand to form a field gravel ditch containing a concealed pipe, which is a field side salt washing channel leading to the alkali drainage channel. Then level the land, mix 20cm of topsoil with sand, apply 2000kg of decomposed cattle and sheep manure, 500kg of superphosphate and 20kg of urea per mu, turn and harrow evenly, and make full use of slack water for winter irrigation of 200m 3 / mu salt washing; repair the drainage ditch, the ditch depth is 3 meters, and connect the irrigation area drainage channel network; Planting of salt absorbing plants: e. The following year, after the land in step d is rotary tilled and suppressed, the saltwort seeds and river sand are evenly mixed in half, and the seeder completes the digging of shallow furrows, laying of drip irrigation belts, and sowing at one time; dripping water immediately after sowing, and the wet peak is determined to be the top of the furrow; dripping water once every 2 days in the morning, and the furrow is determined to be free of water; after 15 days, watering is performed when it is dry and wet; 10kg / mu of urea is dripped with water after the seedlings are 10cm tall, and dripping is applied 4 times during the growth period; Return the whole plant to the field: f. In autumn, when the biomass of Suaeda salsa in step e is the largest, crush the stalks with a stalk beater, spread 20 kg urea / mu, then deep plow and return the field, flood the field with 200 m3 of canal water, and then irrigate the field. 3 / mu, wash the salt and ferment the soil organic matter; continue to plant the salt-absorbing plant Salicornia herba the following year, repeat steps e and f to wash the salt sideways, transform the heavy saline soil structure, plant pioneer crops after 2-3 years and create new arable land. Example 2

[0014] In 2024, the method of constructing a side-washing salt channel to transform heavy saline soil was tested in the Second Company of Hongqi Farm, the Third Agricultural Division; Plot selection: a. In the autumn rest period, choose heavy saline soil with a salt content of 5%, level the land, and plan it into a ridge field with a length of 300m and a width of 100m, with a ridge height of 50cm and a width of 40cm; Side wash salt channel construction: b. Use a single-chain rotary furrow opener with a 16cm blade on the chain and a 150-horsepower agricultural machine for traction. If necessary, modify and replace the furrow opener accessories according to local conditions. Drill parallel furrows vertically along the drainage canal with a depth of 1.2m, a width of 30cm and a spacing of 6m. Adjust the tractor traction hydraulic device and travel speed to control the furrow depth and width. Divide the entire field into parallel strips of soil vertically along the drainage canal through a 1.2-meter deep furrow, and build an independent unit for side-washing salt with strips of soil, deep furrows and strips of soil alternating between them. Prefabricated concealed pipe: c. Drill 60 holes / m with a hole diameter of 5mm on the upper surface of the PVC pipe, then wrap the PVC pipe with a layer of permeable geotextile. The geotextile and gravel layer serve as the outer filter layer, and install a ball valve at the outlet of the tail end of the PVC pipe; d. After the trenching in step b, lay a layer of permeable geotextile from bottom to top, fill with 15cm gravel with a particle size of about 2cm, lay the PVC pipe in step c with a diameter of 125mm on the gravel, with the perforated surface facing up, and the PVC pipe is inclined to the alkali drainage channel with a gradient of 1 / 700. Cover the PVC pipe with 15cm deep gravel, permeable geotextile, 60cm of sand and gravel and 30cm of river sand to form a field gravel ditch containing a concealed pipe, which is a field side salt washing channel leading to the alkali drainage channel. Then level the land, mix 20cm of topsoil with sand, apply 2000kg of decomposed cattle and sheep manure, 500kg of superphosphate and 20kg of urea per mu, turn and harrow evenly, and make full use of slack water for winter irrigation of 400m 3 / mu salt washing; repair the drainage ditch, the ditch depth is 3 meters, and connect the irrigation area drainage channel network; Planting of salt absorbing plants: e. The following year, after the land in step d is rotary tilled and suppressed, the saltwort seeds and river sand are evenly mixed in half, and the seeder completes the digging of shallow furrows, laying of drip irrigation belts, and sowing at one time; dripping water immediately after sowing, and the wet peak is determined to be the top of the furrow; dripping water once every 2 days in the morning, and the furrow is determined to be free of water; after 15 days, watering is carried out when it is dry and wet; 20kg / mu of urea is dripped with water after the seedlings are 10cm tall, and dripping is applied 4 times during the growth period; Return the whole plant to the field: f. In autumn, when the biomass of Suaeda salsa in step e is the largest, crush the stalks with a stalk beater, spread 20 kg urea / mu, then deep plow and return the field, and flood the field with 400 m3 of canal water. 3 / mu, wash the salt and ferment the soil organic matter; continue to plant the salt-absorbing plant Salicornia herba the following year, repeat steps e and f to wash the salt sideways, transform the heavy saline soil structure, plant pioneer crops after 2-3 years and create new arable land.

[0015] The present invention discloses a method for constructing a side-washing salt channel to transform heavy saline soil. In this method, the maximum side-washing salt rate of the soil (0-120 cm) is 30%, and the maximum side-washing salt rate of the topsoil (0-20 cm) is 50%. Salt-absorbing plants are planted and returned to the fields. After saturated water fermentation, the salt content of the soil is reduced by 43% in the same year. Through large-scale continuous planting and replacement of pioneer crops, the soil salt content can be gradually reduced, the soil structure and biological fertility can be gradually improved, and new arable land can be created.

Claims

1. A method for constructing a side-washing salt channel to transform heavy saline soil. Features Follow these steps: Plot selection: a. In the autumn rest period, choose heavy saline soil with a salt content of 5-7%, level the land, and plan it into a ridge field with a length of 300m and a width of 100m, with a ridge height of 50cm and a width of 40cm; Side wash salt channel construction: b. Use a single-chain rotary furrow opener with a 15cm blade on the chain, pulled by a 50-horsepower agricultural machine, and open parallel furrows vertical to the drainage canal. The furrows are 1.2m deep, 30cm wide, and 6m apart. The entire field is divided into parallel strips of soil vertical to the drainage canal through 1.2m deep furrows, and an independent unit for side-washing salt is built with strips of soil, deep furrows, and strips of soil alternating between them. Prefabricated concealed pipe: c. Drill 60 holes / m with a hole diameter of 5mm on the upper surface of the PVC pipe, then wrap the PVC pipe with a layer of permeable geotextile. The geotextile and gravel layer serve as the outer filter layer, and install a ball valve at the outlet of the tail end of the PVC pipe; d. After the trenching in step b, a layer of permeable geotextile is laid from bottom to top, and 15 cm of gravel with a particle size of 2 cm is filled. The PVC pipe in step c with a diameter of 125 mm is laid on the gravel, with the perforated surface facing upward. The PVC pipe is inclined toward the alkali drainage channel with a gradient of 1 / 600-700. The PVC pipe is covered with 15 cm deep gravel, permeable geotextile, 60 cm of sand and gravel and 30 cm of river sand to form a field gravel ditch containing a concealed pipe, which is a field side salt washing channel leading to the alkali drainage channel. Then the land is leveled, 20 cm of topsoil is mixed with sand, 2000 kg of decomposed cattle and sheep manure, 500 kg of superphosphate and 20 kg of urea are applied per mu, and the soil is turned over and harrowed evenly to make full use of the slack water for winter irrigation of 200-600 m 3 / mu salt washing; repair the drainage ditch, the ditch depth is 3 meters, and connect the irrigation area drainage channel network; Planting of salt absorbing plants: e. The following year, after the land in step d is rotary tilled and suppressed, the saltwort seeds and river sand are evenly mixed in half, and the seeder completes the digging of shallow furrows, laying of drip irrigation belts, and sowing at one time; dripping water immediately after sowing, and the wet peak is determined to be the top of the furrow; dripping water once every 2 days in the morning, and the furrow is determined to be free of water; after 15 days, watering is carried out when it is dry and wet; 10-20kg / mu of urea is applied with water drops after the seedlings are 10cm tall, and drip application is carried out 4 times during the growth period; Return the whole plant to the field: f. In autumn, when the biomass of the Salicornia herba in step e is the largest, crush the stalks with a stalk beater, spread 20 kg urea / mu, and then deep plow the field and flood the field with canal water at 200-400 m 3 / mu, wash the salt and ferment the soil organic matter; continue to plant the salt-absorbing plant Salicornia herba the following year, repeat steps e and f to wash the salt sideways, transform the heavy saline soil structure, plant pioneer crops after 2-3 years and create new arable land.