A method for constructing a capillary channel by moving salt and improving soil

Abstract

The application relates to a salt-removing and soil-improving method for constructing a capillary channel, aiming at the problem of deep salt accumulation in water-saving farmland in arid areas and the problem of year-by-year aggravation, the method is characterized by the following steps: washing salt by using light water through film drip irrigation on the ridge, laying film at the bottom of the ridge ditch, filling high-water-conducting organic material, inserting water guide straw in the organic material, and covering the straw with multilayer black cotton fiber, forming an arched evaporation surface between the films, that is, a continuous capillary channel is built, salt is enriched in the porous cotton fiber material, after salt accumulation balance, the outer layer is regularly removed, dry salt discharge and recovery in the farmland are realized, and the farmland tillage layer is actively desalted and fertilized year by year through ditch and ridge exchange and cooperation with inter-annual period water winter irrigation.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of saline-alkali soil improvement, and particularly relates to a method for moving salt and improving soil by constructing capillary channels in a drip-irrigated farmland under a film in a dry region. BACKGROUND

[0002] Xinjiang is an important agricultural reclamation area in China. The water and soil development and oasis construction in the area have played a great leading role, promoted the development of production, and pushed the social progress. In particular, since the emergence of the drip irrigation technology under the film in 1996, the technology has been rapidly developed and widely applied in Xinjiang due to its effects of temperature increase, soil conservation, water saving, and salt suppression, thereby providing important technical support for water saving and yield increase of irrigated agriculture. However, with the extension of the planting period under the drip irrigation technology under the film, the soil salt content in the 40-80 cm depth of the cultivated layer has a gradually increasing trend, which has caused 31.1% of the existing cultivated land to be damaged by salinization, thereby increasing the potential risk of salinization in the oasis. How to achieve the salt balance of the drip-irrigated farmland under the film and prevent the occurrence of secondary salinization of the soil has become a problem to be solved at present.

[0003] Soil water is the carrier of soil salt transport. Under the condition of drip irrigation, with the infiltration of water, the water flow can bring salt into the edge of the wetting front, so that the soil salt is transported in the three-dimensional space. The continuous dripping of water under the drip irrigation technology gradually pushes the water in a pulse mode. In the case of large drip head flow, the soil water under the film is saturated too fast, so that the lateral movement of water and salt is faster than the downward movement, thereby forming the lateral seepage of salt water to the space between the films for salt washing. However, it is not difficult to find that the spatial distribution of soil water and salt at the field scale under the drip irrigation technology under the film has obvious heterogeneity compared with other irrigation methods. The salt in the space between the films and the 40-60 cm soil layer is a strong accumulation area.

[0004] Cotton fiber material, grass charcoal, straw inner microtubule cellulose, and lignin are the strongest materials for capillary phenomenon in nature. The continuous capillary channels are constructed by using these natural materials in the farmland, the salt is enriched in the cotton fiber layer with a raised shape, and then the salt is removed, which is a fast and environmentally friendly method for reducing salt and improving soil in the farmland. After the agricultural experiments in Hongqi Farm of the Third Agricultural Division and Karamay, the research group has summarized the method for moving salt and improving soil by constructing capillary channels, which is suitable for the light and moderate saline-alkali farmland in the dry region, and can improve the water and salt regulation capacity at the field scale under water-saving irrigation, and enrich the technology and theoretical system for improving saline-alkali soil. SUMMARY

[0005] The application aims to provide a salt removal and soil improvement method for constructing capillary channels, aiming at the problem of deep salt accumulation with the extension of planting years in water-saving irrigation farmland in arid regions, which washes salt by light water drip irrigation on the ridge, lays film on the bottom of the ridge ditch, fills high water-conducting organic material, inserts water guide straw in the organic material, covers multiple layers of black cotton fiber, forms an arched evaporation surface between the films, builds continuous capillary channels, enriches salt in the porous cotton fiber material, and realizes dry salt removal and recovery in the farmland after salt accumulation balance by regularly removing the outer layer; and gradually realizes farmland topsoil desalination and fertilization by exchanging ridge and ditch and cooperating with inter-annual period water winter irrigation.

[0006] The salt removal and soil improvement method for constructing capillary channels is performed according to the following steps:

[0007] Land selection:

[0008] a. Selecting slightly or moderately saline-alkali soil in an oasis in an arid region;

[0009] Dredging the drainage ditch and controlling the underground water level at the critical depth:

[0010] b. Repairing and connecting the drainage ditch where the saline-alkali soil selected in step a is located, the ditch has a width of 7-10 meters, a depth of 2.5-3 meters, and a bottom width of 1-2 meters; an observation well is built to dynamically track the water level and salinity;

[0011] Leveling the land and improving and fertilizing the soil (1):

[0012] c. Leveling the land in autumn or spring, deepening 60 cm with a deepening shovel, then spreading 2000 kg of mature livestock manure and 30 kg of compound fertilizer per mu, and then deep plowing 40 cm and raking and leveling;

[0013] Cotton planting:

[0014] d. Ditching and ridging with a cotton seeder, laying drip irrigation tape, covering film (2), and completing once by point planting, adopting one film, double pipes, and four rows, the film has a width of 1.25 m, the ridge and ditch have a depth of 25 cm and a width of 60 cm; a drip irrigation tape with a Φ16 mm, 3.0 L / h large drip head flow is adopted;

[0015] Continuous capillary channel construction:

[0016] e. After completing step d, laying a film (2) from bottom to top in the ridge and ditch, the film has a width of 60 cm, filling 30 cm of grass charcoal soil (3), inserting straw (4) with a cotton fiber layer (5) in the grass charcoal soil (3), the straw has a stalk height of 25-30 cm, and the insertion density is 20 / m 2 , then covering 7-10 layers of black cotton fiber layer (5), each layer has a thickness of 4 mm, the ridge and ditch filling is 5-10 cm higher than the planting ridge, and the straw (4) is cotton stalk or reed stalk;

[0017] Water and fertilizer management:

[0018] f. drip irrigation 16m continuously after sowing 3 / mu to provide seedling water, for film washing salt and interfilm salt accumulation, to ensure that the salt water level in the film moves more than vertically; drip water during seedling stage: drip water 7-10 days after seedling water, each time 20 m 3 / mu, drip water once every 7 days; drip water during flowering and boll stage: drip irrigation once every 10 days, each time 25 m 3 / mu; drip water during boll stage: drip irrigation once every 10 days, each time 35 m 3 / mu; each irrigation amount includes plant growth water and film under salt washing water;

[0019] Drip 5 times of urea during the growth period, total amount 80 kg / mu;

[0020] Periodic salt removal:

[0021] g. Use a modified film laying machine or manually collect the cotton fiber layer (5) periodically, collect one layer every 15 days in the early stage, collect one layer every 30 days in the middle stage, and collect all the cotton fiber layers out of the farmland until the harvesting period after the cotton ridge is sealed; the salt-adsorbed cotton fiber is washed and used again in the next season;

[0022] Gully and ridge exchange:

[0023] h. Before spring sowing the next year, crush the cotton stalks with a stalk machine, extract the ridge film, and deep plow the ridge grass and charcoal soil and the crushed cotton stalks into the soil for returning to the field; exchange the gully and ridge during sowing, and complete the salt removal and soil improvement of the whole land year by year.

[0024] The salt removal and soil improvement method for constructing capillary channels according to the application can be matched with winter irrigation every 3-5 years, and can realize soil desalination and fertilization year by year.

[0025] The salt removal and soil improvement method for constructing capillary channels according to the application has the following characteristics:

[0026] In view of the problem that deep salt accumulation and salinization in arid area farmland is getting worse year by year, the application simulates the dry salt discharge technology in nature, builds water potential difference through gully and ridge, facilitates water and salt lateral seepage, and provides driving force for water and salt to reduce deep movement and quickly flow laterally by drip irrigation of fresh water, plant growth water and salt washing water through large drip head under the film on the ridge; the gully and ridge film receives the salt washing water generated by drip irrigation under the film on the ridge, provides a storage area for water solution for dry evaporation; the grass charcoal and cotton fiber straw in the gully and ridge film are buried and planted to form vertical water channels; the straw is covered with multiple layers of black cotton fiber porous material to form an evaporation and salt accumulation surface, and the salt accumulation layer is removed periodically to break the balance and continuously remove salt. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1The structural schematic diagram of the present application. DETAILED DESCRIPTION Embodiment 1

[0028] In 2023-2024, the present application was used for salt transplanting and soil improvement test in Karamay large-scale agriculture:

[0029] Plot selection:

[0030] a. Selecting slightly or moderately saline-alkali soil in oasis of arid region;

[0031] Dredging drainage ditch and controlling underground water level at critical depth:

[0032] b. Repairing and connecting the drainage ditch where the saline-alkali soil selected in step a is located, with 7-meter wide and 2.5-meter deep ditch top, 1.5-meter wide bottom; building observation well to dynamically track water level and salinity;

[0033] Leveling land and improving and fertilizing soil 1:

[0034] c. Leveling land in autumn, deep plowing 60 cm with deep plow, then spreading 2000 kg of mature livestock manure and 30 kg of compound fertilizer per mu, and then deep plowing 40 cm and raking evenly and leveling;

[0035] Cotton planting:

[0036] d. After rotary tillage in spring, cotton seeding machine is used for ditching, ridging, laying drip irrigation belt and film 2, and one-time seeding is completed, with one film, double pipes and four rows, film width of 1.25 m, ditch and ridge depth of 25 cm, and width of 60 cm; drip irrigation belt with Φ16 mm, 3.0 L / h large drip head flow is used;

[0037] Continuous capillary channel construction:

[0038] e. After step d is completed, film 2 is laid from bottom to top in ditch and ridge, with film width of 60 cm, 30 cm grass carbon soil 3 is filled, reed stalk 4 with cotton fiber layer 5 is inserted and twisted in grass carbon soil 3, with stalk height of 25 cm and insertion density of 20 / m 2 , then 7 layers of black cotton fiber layer 5 are covered, with thickness of 4 mm each, and the filling material in ditch and ridge is 5 cm higher than the seeding ridge after filling;

[0039] Water and fertilizer management:

[0040] f. After sowing, 16 m 3 / mu of water is provided for seedling emergence, which is used for salt washing in film and salt accumulation between films, to ensure that the horizontal migration of dissolved salt water in the film is greater than the vertical migration; seedling stage drip water: after 7 days of seedling emergence drip irrigation, 20 m 3 / mu of water is dripped each time, and the drip irrigation is performed once every 7 days; flower and boll stage drip water: drip irrigation is performed once every 10 days, with 25 m 3 / mu of water each time; boll stage drip water: drip irrigation is performed once every 10 days, with 35 m of water each time.3 The water amount for each irrigation includes water for plant growth and salt washing water under the film, and the two are in equal proportion to achieve the functions of desalination under the film and salt accumulation between the films;

[0041] During the growth period, 5 times of urea are applied by water dripping, and the total amount is 80 kg per mu;

[0042] Periodic salt removal:

[0043] g, the cotton fiber layer 5 is collected by using a modified film laying machine, one layer is collected every 15 days in the early stage, one layer is collected every 30 days in the middle stage, and all the cotton fiber layers are collected and taken out of the farmland before the harvesting period after the cotton ridge is closed, and the cotton fiber layers adsorbing salt are washed and used again in the next season;

[0044] Gully and ridge exchange:

[0045] h, before spring sowing of the next year, the cotton stalks are crushed by a stalk machine, the ridge and gully films are pulled out, the grass and charcoal soil in the ridge and the crushed cotton stalks are deep plowed into the soil and returned to the field, and the gully and ridge are exchanged during sowing.

[0046] By implementing the above measures, winter irrigation is matched once every 3-5 years, and the soil can be desalted and fertilized year by year. Embodiment 2

[0047] In 2024, the application carried out a salt removal and soil improvement planting test in Hongqi Farm of Nong Sanji:

[0048] Plot selection:

[0049] a, select a light or moderate saline soil in an oasis in an arid area;

[0050] Dredge the drainage ditch and control the underground water level below the critical depth:

[0051] b, repair and connect the drainage ditch where the saline soil selected in step a is located, the ditch has a width of 10 meters and a depth of 3 meters, and a bottom width of 2 meters; build an observation well to dynamically track the water level and salinity;

[0052] Leveling the land and improving the soil 1:

[0053] c, level the land in spring, deep plow 60 cm with a deep plow, then spread 2000 kg of mature livestock manure and 30 kg of compound fertilizer per mu, and then deep plow 40 cm and evenly rake and level;

[0054] Cotton planting:

[0055] d, the cotton sowing machine digs a ditch, raises a ridge, lays a drip irrigation belt, covers a film, and points to sow once, which is completed by using one film and double pipes four rows, the film width is 1.25 m, the ridge and ditch depth is 25 cm, and the width is 60 cm; a drip irrigation belt with a Φ16 mm, 3.0 L / h large drip head flow is used;

[0056] Continuous capillary channel construction:

[0057] e、After step d is completed, the furrow is filled with 30 cm of grass charcoal soil 3, and the cotton stalks 4 with the cotton fiber layer 5 wrapped therearound are inserted into the grass charcoal soil 3, with a stalk height of 30 cm and an insertion density of 20 per meter 2 Then, 10 layers of black cotton fiber layers 5 are covered, with a thickness of 4 mm per layer, and the furrow filling is 10 cm higher than the seeding ridge;

[0058] Water and fertilizer management:

[0059] f、After sowing, uninterrupted drip irrigation is performed for 16 m 3 / mu to provide seedling water, which is used for salt washing in the film and salt accumulation between the films, to ensure that the horizontal migration of the dissolved salt water in the film is greater than the vertical migration; seedling water drip: after 10 days of seedling water drip irrigation, the amount of water drip irrigation is 20 m 3 / mu each time, and the water drip irrigation is performed once every 7 days; flower and boll period drip water: drip irrigation is performed once every 10 days, and the amount of water drip irrigation is 25 m 3 / mu each time; bolling period drip water: drip irrigation is performed once every 10 days, and the amount of water drip irrigation is 35 m 3 / mu each time; the amount of water drip irrigation each time includes water for plant growth and salt washing water under the film, and the two can be used in equal proportions to complete the functions of desalination under the film and salt accumulation between the films;

[0060] During the growth period, 5 times of urea are driped with water, with a total amount of 80 kg / mu;

[0061] Regular salt removal:

[0062] g、The cotton fiber layer 5 is collected manually at regular intervals, one layer is collected every 15 days in the early stage, and one layer is collected every 30 days in the middle stage; after the cotton ridge is closed, all the cotton fiber layers are collected and taken out of the farmland by the time of the harvesting period, and the cotton fiber that absorbs salt is washed and used again in the next season;

[0063] Ridge and furrow exchange:

[0064] h、Before spring sowing the next year, the cotton stalks are crushed by a stalk machine, the ridge and furrow mulching films are extracted, the grass charcoal soil in the ridge and the crushed cotton stalks are plowed into the soil and returned to the field, and the ridge and furrow are exchanged during sowing.

[0065] By implementing the above measures, winter irrigation is matched once every 3-5 years, and the soil can be desalted and fertilized year by year.

[0066] The test results of the method in the invention in the light and medium saline soil in Karamay and Hongqi Farm show that in 2023, the cotton grows vigorously, with a yield of about 350 kg per mu, which is flat compared with the ordinary planting mode, the straw amount is increased by 1 / 3, the organic matter in 0-20 cm is increased by 21.6%, the cotton fiber layer salt removal is 196.8 g / m 2 , the soil salt content in 0-20 cm after leveling and harrowing is reduced by 32.8%, and the deep layer salt content in 40-60 cm does not change significantly.

[0067] In 2024, Karamay's cotton yield reached 400 kg / mu based on the previous year's salt removal. Compared with the previous year, the organic matter in 0-20 cm increased by 15.6%, the soil salt content in 0-20 cm decreased by 18.5% after leveling and harrowing, and the salt content in 40-60 cm did not change significantly. In Hongqi Farm, the cotton yield reached 450 kg / mu, and the cotton fiber layer salt moved 276.8 g / m 2 , 0-20 cm soil, horizontal desalination of 63.9% compared with film and film, 40-60 cm soil salt accumulation was not obvious.

Claims

1. A method of constructing a capillary channel for salt transport and soil modification, characterized in that The following steps are taken: Plot selection: a. Selecting slightly or moderately saline-alkali soil in oasis in arid areas; Dredging drainage ditches and controlling groundwater level at critical depth: b. Repairing and connecting drainage ditches where saline-alkali soil selected in step a is located, with a width of 7-10 meters at the top of the ditch, a depth of 2.5-3 meters, a bottom width of 1-2 meters; build observation wells to dynamically track water level and salinity; Land leveling, soil improvement and fertilization (1): c. Leveling the land in autumn or spring, deep plowing 60 cm with a deep plow, then spreading 2000 kg of mature livestock manure and 30 kg of compound fertilizer per mu, then deep plowing 40 cm and raking evenly and flatly; Cotton planting: d. Cotton seeding machine ditching and ridging, laying drip irrigation tape, covering film (2), and one-time seeding, using one film with double pipes and four rows, with a film width of 1.25 m, a ditch depth of 25 cm, and a width of 60 cm; using Φ16 mm, 3.0 L / h large drip head flow drip irrigation tape; Continuous capillary channel construction: e、After step d, lay film (2) from bottom to top in the furrow, film width 60 cm, fill 30 cm grassy carbon soil (3), and insert straw (4) with cotton fiber layer (5) in the carbon soil (3), with a height of 25-30 cm, and a density of 20 per meter 2 Then cover 7-10 layers of black cotton fiber layer (5), with a thickness of 4 mm per layer, and the filling in the furrow is 5-10 cm higher than the seeding ridge, wherein the straw (4) is cotton stalk or reed stalk Water and fertilizer management: f. drip irrigation 16 m 3 / acre after sowing to provide seedling water, to wash salt inside the film and to accumulate salt between the films, to ensure that the horizontal migration of salt-dissolving water inside the film is greater than the vertical migration; seedling stage drip water: drip water 7-10 days after the seedling water, each time 20 m 3 / acre, drip water once every 7 days; flower and bud stage drip water: drip irrigation once every 10 days, each time 25 m 3 / acre; full-bud stage drip water: drip irrigation once every 10 days, each time 35 m 3 / acre; each irrigation amount includes plant growth water and salt washing water under the film; Drip applying 5 times of urea during the growth period, with a total amount of 80 kg per mu; Regular salt removal: g. Using a modified film laying machine or manual method to regularly collect cotton fiber layer (5), collecting one layer every 15 days in the early stage; collecting one layer every 30 days in the middle stage; after cotton is sealed, all cotton fiber layers are collected out of the farmland by the harvesting period, and the salt-adsorbing cotton fiber is washed and used again in the next season; Gully and ridge exchange: h. Before spring sowing the next year, the stalk machine is used to crush the cotton stalks, the ridge ditch film is pulled out, the grass and charcoal soil in the ridge is deep plowed into the soil, and the gully and ridge are exchanged during sowing, and the whole land salt removal and soil improvement is completed year by year.

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