Salt removing and soil improving method for constructing capillary channels

Abstract

The invention relates to a salt transfer and soil improvement method for constructing capillary channels, which aims at the problems of deep salt accumulation and year-by-year aggravation of a water-saving farmland in an arid region, and comprises the following steps: drip irrigation of fresh water under a film on a ridge for salt leaching, film laying at the bottom of a furrow, landfill of a high-water-conductivity organic material, cuttage of water diversion straws in the organic material, and covering of a plurality of layers of black cotton fibers. An arch-shaped raised evaporation surface between the membranes is formed, namely, a continuous capillary channel is built, salt is enriched in a porous cotton fiber material, after salt accumulation is balanced, an outer layer is removed regularly, and dry discharged salt recovery in the farmland is achieved; and in cooperation with interchange of furrows and ridges and winter irrigation of inter-annual period slack farming water, farmland plough layer desalination and fertilization are actively realized year by year.

Description

Technical Field

[0001] The invention belongs to the field of saline-alkali soil improvement, and in particular relates to a method for removing salt and improving soil by constructing a capillary channel in arid areas through drip irrigation of farmland under film. Background Art

[0002] Xinjiang is an important agricultural reclamation area in my country. The water and soil development and oasis construction in the area have played a great leading role, promoted the development of production, and promoted social progress. In particular, since its introduction in 1996, sub-film drip irrigation technology has been rapidly developed and promoted in Xinjiang due to its functions of warming, moisture conservation, water saving, and salt suppression, providing important technical support for water saving and increasing production in irrigation agriculture. However, with the extension of the planting period of sub-film drip irrigation, the salinity of sub-film drip irrigation farmland has gradually increased at a depth of 40-80cm in the tillage layer, causing 31.1% of the existing cultivated land to be damaged by salinity, increasing the potential risk of salinization in the oasis. How to achieve salt balance in sub-film drip irrigation farmland and prevent the occurrence of secondary soil salinization has become a problem that needs to be solved urgently.

[0003] Soil moisture is the carrier of soil salt migration. Under drip irrigation conditions, along with the infiltration of water, water flow can bring salt to the edge of the wet peak, causing soil salt to migrate in three-dimensional space. Drip irrigation drips continuously and advances gradually in a pulsed manner. Under large dripper flow, the soil water under the membrane is saturated too quickly, causing the lateral movement of water and salt to be faster than the downward movement, forming lateral infiltration of dissolved salt water to flow to the membrane to wash salt. However, it is not difficult to find that the spatial distribution of soil moisture and salt under drip irrigation under the membrane has obvious heterogeneity at the field scale compared with other irrigation methods. The salt between the membrane and the 40-60cm soil layer is a strong concentration area.

[0004] Cotton fiber materials, peat, microtubule cellulose and lignin in straw are all materials with the strongest capillary phenomena in nature. Using these natural materials to construct continuous capillary channels in farmland, divert water and salt to the ridged cotton fiber layer, and then remove them is currently a fast and environmentally friendly method for reducing salt and improving soil in farmland. After experiments at Hongqi Farm of the Third Agricultural Division and Karamay Agricultural University, the research team concluded that the construction of capillary channels is suitable for salt removal and soil improvement methods in slightly to moderately saline-alkali farmland in arid areas, which can improve the water and salt regulation capacity of farmland scale under water-saving irrigation and enrich the saline-alkali soil improvement technology and theoretical system. Summary of the invention

[0005] The purpose of the present invention is to provide a method for salt removal and soil improvement by constructing capillary channels. The method aims at the problem of deep salt accumulation in water-saving irrigation farmland in arid areas as the planting years extend. The method comprises the following steps: fresh water drip irrigation under the film on the ridges to wash the salt, film laying at the bottom of the ridge furrows, burying highly water-conductive organic materials, inserting water-conducting straws in the organic materials, and covering with multiple layers of black cotton fibers to form an arched evaporation surface between the membranes, that is, to construct a continuous capillary channel, to enrich the salt in the porous cotton fiber material, and to remove the outer layer regularly after the salt accumulation is balanced, so as to realize the dry drainage salt recovery in the farmland; the ridges and furrows are interchanged, and the winter irrigation with water during the agricultural slack season during the inter-annual cycle is coordinated to gradually realize the desalination and fertilization of the farmland plow layer.

[0006] The salt removal and soil improvement method for constructing a capillary channel described in the present invention is carried out according to the following steps: Plot selection: a. Select slightly or moderately saline-alkali soil in oases in arid areas; Clear drainage channels and control groundwater level at critical depth: b. Repair and connect the drainage channel where the saline-alkali soil selected in step a is located, with an upper width of 7-10 meters, a depth of 2.5-3 meters, and a bottom width of 1-2 meters; build an observation well to dynamically track the water level and mineralization; Leveling the land, improving and fertilizing the soil (1): c. Level the land in autumn or spring, use a deep tillage shovel to deep till 60cm, spread 2000kg of decomposed animal manure and 30kg of compound fertilizer per mu, then deep till 40cm and harrow evenly; Cotton Planting: d. The cotton planter opens furrows and ridges, lays drip irrigation tape, covers the film (2), and sows seeds at one time. It uses one film, two tubes, and four rows. The film width is 1.25m. The furrow is 25cm deep and 60cm wide. It uses a drip irrigation tape with a diameter of 16mm and a large dripper flow rate of 3.0L / h. Continuous capillary channel construction: e. After completing step d, a film (2) is laid from bottom to top in the furrow, with a width of 60 cm, and a 30 cm layer of peat soil (3) is filled. Straw (4) wrapped with a cotton fiber layer (5) is inserted into the peat soil (3), with a stalk height of 25-30 cm and a insertion density of 20 stalks / m 2 , then covered with 7-10 layers of black cotton fiber layers (5), each layer 4 mm thick, the ridge furrow filling is 5-10 cm higher than the sowing ridge, wherein the straw (4) is cotton straw or reed straw; Water and fertilizer management: f. Continuous drip irrigation after sowing for 16m 3 / mu provides water for seedling emergence, which is used for washing salt inside the membrane and gathering salt between membranes, ensuring that the horizontal movement of dissolved salt water inside the membrane is greater than the vertical movement; drip irrigation during seedling stage: 7-10 days after seedling emergence, the dripping amount is 20 m 3 / mu, drip irrigation once every 7 days; drip irrigation during flowering and bolling period: drip irrigation once every 10 days, 25m3 / mu; Drip irrigation during the full-boll period: drip irrigation every 10 days, with a drip volume of 35 m 3 / mu‌; The amount of water for each irrigation includes water for plant growth and salt water for washing under the film; During the growth period, urea was applied five times with water drops, with a total dosage of 80 kg / mu; Regular salt removal: g. Use a modified film-laying machine or manually collect the cotton fiber layer (5) regularly, collecting one layer every 15 days in the early stage; collecting one layer every 30 days in the middle stage; after the cotton ridges are sealed, all the cotton fibers are collected and taken out of the farmland at the harvest time, and the cotton fibers that absorb salt are washed and used again in the next season; Furrow ridge interchange: h. Before sowing in the next spring, the cotton stalks are crushed with a stalk beater, the plastic film on the ridges is pulled out, the peat soil and the crushed cotton stalks in the ridges are deeply plowed into the soil and returned to the field. When sowing, the ridges and furrows are interchanged, and the salt removal and soil improvement of the entire land are completed year by year.

[0007] The salt removal and soil improvement method for constructing a capillary channel described in the present invention is equipped with winter irrigation every 3-5 years, which can achieve desalination and soil fertilization year by year.

[0008] The salt removal and soil improvement method for constructing a capillary channel described in the present invention is characterized by: Aiming at the problem of deep salt accumulation and salinization in water-saving farmland in arid areas getting worse year by year. The present invention simulates the dry salt drainage technology in nature, and constructs water potential height difference through furrows and ridges, which is conducive to the lateral infiltration of water and salt; the large dripper flow rate under the film on the ridge drip irrigation of fresh water, plant growth water and washing salt water is given equal weight, which provides driving force for reducing the deep movement of water and salt and rapid lateral flow; the ridge furrow film is laid to receive the washing salt water produced by drip irrigation under the film on the ridge, providing a storage area for aqueous solution for dry drainage evaporation; the film in the ridge furrow is filled with peat and peat cuttings and wrapped with cotton fiber straw to form a vertical water guide channel; the straw is covered with multiple layers of black cotton fiber porous material to form an evaporation salt accumulation surface, and the salt enrichment layer is removed regularly to interrupt the balance of continuous salt migration; the furrows and ridges are interchanged to match the annual cycle winter irrigation, dredge the drainage network, and actively realize the rapid removal of the root layer and fertilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION Example 1

[0010] In 2023-2024, the invention will be used to carry out planting, salt removal and soil improvement experiments in Karamay Agriculture: Plot selection: a. Select slightly or moderately saline-alkali soil in oases in arid areas; Clear drainage channels and control groundwater level at critical depth: b. Repair and connect the drainage channel where the saline-alkali soil selected in step a is located, with an upper width of 7 meters, a depth of 2.5 meters, and a bottom width of 1.5 meters; build an observation well to dynamically track the water level and mineralization; Level the land, improve and fertilize the soil 1: c. Level the land in autumn. Use a deep tillage shovel to deep till 60cm, spread 2000kg of decomposed animal manure and 30kg of compound fertilizer per mu, then deep till 40cm and harrow evenly; Cotton Planting: d. After spring rotary tillage, the cotton planter digs furrows and ridges, lays drip irrigation tape, covers the film 2, and completes the sowing in one go. One film, two tubes and four rows are used. The film width is 1.25m, the furrow is 25cm deep and 60cm wide. The drip irrigation tape with a Φ16mm and a large dripper flow of 3.0L / h is used; Continuous capillary channel construction: e. After completing step d, the ridges are covered with a film 2 from bottom to top, with a film width of 60 cm, and filled with 30 cm of peat soil 3. Reed stalks 4 wrapped with a cotton fiber layer 5 are inserted into the peat soil 3, with a stalk height of 25 cm and a cutting density of 20 stalks / m 2 , then cover with 7 layers of black cotton fiber 5, each layer 4mm thick, and the ridges are 5cm higher than the sowing ridges after filling; Water and fertilizer management: f. Continuous drip irrigation after sowing for 16m 3 / mu provides water for seedling emergence, which is used for washing salt inside the membrane and gathering salt between membranes, ensuring that the horizontal movement of dissolved salt water inside the membrane is greater than the vertical movement; drip irrigation during seedling stage: 7 days after seedling emergence, the dripping amount is 20 m 3 / mu, drip irrigation once every 7 days; drip irrigation during flowering and bolling period: drip irrigation once every 10 days, 25m 3 / mu; Drip irrigation during the full-boll period: drip irrigation every 10 days, with a drip volume of 35 m 3 / mu‌; Each irrigation volume includes water for plant growth and salt water for washing under the membrane, and the two are in equal proportions to complete the functions of under-membrane desalination and inter-membrane salt accumulation; During the growth period, urea was applied five times with water drops, with a total dosage of 80 kg / mu; Regular salt removal: g. Use a modified film-laying machine to collect cotton fiber layers 5, one layer every 15 days in the early stage; one layer every 30 days in the middle stage; after the cotton ridges are sealed, all the cotton fibers are collected and taken out of the farmland during the harvest period, and the cotton fibers that absorb salt are washed and used again in the next season; Furrow ridge interchange: h. Before sowing in the next spring, use a stalk beater to crush the cotton stalks, pull out the mulch film on the ridges, and deeply plow the peat soil and crushed cotton stalks in the ridges and return them to the field. When sowing, swap the ridges and furrows.

[0011] Implementing the above measures, combined with winter irrigation every 3-5 years, can achieve annual desalination and soil fertilization. Example 2

[0012] In 2024, the invention carried out salt removal and soil improvement planting experiments at Hongqi Farm of the Third Agricultural Division: Plot selection: a. Select slightly or moderately saline-alkali soil in oases in arid areas; Clear drainage channels and control groundwater level below critical depth: b. Repair and connect the drainage channel where the saline-alkali soil selected in step a is located, with an upper width of 10 meters, a depth of 3 meters, and a bottom width of 2 meters; build an observation well to dynamically track the water level and mineralization; Level the land, improve and fertilize the soil 1: c. Level the land in spring, use a deep tillage shovel to deep till 60cm, spread 2000kg of decomposed animal manure and 30kg of compound fertilizer per mu, then deep till 40cm and harrow evenly; Cotton Planting: d. The cotton seeder digs furrows and ridges, lays drip irrigation tape, and covers the film. 2. The spot planting is completed in one go. One film, two tubes and four rows are used. The film width is 1.25m, the ridge furrow is 25cm deep and 60cm wide. The drip irrigation tape with a Φ16mm and a large dripper flow of 3.0L / h is used. Continuous capillary channel construction: e. After completing step d, the ridges are covered with a film 2 from bottom to top, with a film width of 60 cm, and filled with 30 cm of peat soil 3. Cotton stalks 4 wrapped with a cotton fiber layer 5 are inserted into the peat soil 3, with a stalk height of 30 cm and a cutting density of 20 stalks / m 2 , then cover with 10 layers of black cotton fiber layer 5, each layer thickness 4mm, the ridge furrow filling is 10cm higher than the sowing ridge; Water and fertilizer management: f. Continuous drip irrigation after sowing for 16m 3 / mu provides water for seedling emergence, which is used for washing salt inside the membrane and gathering salt between membranes, ensuring that the horizontal movement of dissolved salt water inside the membrane is greater than the vertical movement; drip irrigation during seedling stage: 10 days after seedling emergence drip irrigation, the amount of each drip is 20 m 3 / mu, drip irrigation once every 7 days; drip irrigation during flowering and bolling period: drip irrigation once every 10 days, 25m 3 / mu; Drip irrigation during the full-boll period: drip irrigation every 10 days, with a drip volume of 35 m 3 / mu‌; Each irrigation volume includes water for plant growth and salt water for washing under the membrane, and the two are in equal proportions to complete the functions of under-membrane desalination and inter-membrane salt accumulation; During the growth period, urea was applied five times with water drops, with a total dosage of 80 kg / mu; Regular salt removal: g. Collect the cotton fiber layer 5 manually at regular intervals, with one layer collected every 15 days in the early stage and one layer collected every 30 days in the middle stage; after the cotton ridges are sealed, all the cotton fibers are collected and taken out of the farmland during the harvest period, and the cotton fibers that absorb salt are washed and used again in the next season; Furrow ridge interchange: h. Before sowing in the next spring, use a stalk beater to crush the cotton stalks, pull out the mulch film on the ridges, and deeply plow the peat soil and crushed cotton stalks in the ridges and return them to the field. When sowing, swap the ridges and furrows.

[0013] Implementing the above measures, combined with winter irrigation every 3-5 years, can achieve annual desalination and soil fertilization.

[0014] The test results of the method described in the present invention on light and moderate saline-alkali soil in Karamay and Hongqi Farm showed that in 2023, cotton grew vigorously, with an output of about 350 kg per mu. Compared with the ordinary planting mode, the yield remained the same, the amount of straw increased by 1 / 3, the organic matter in 0-20 cm increased by 21.6%, and the salt migration of cotton fiber layer was 196.8 g / m 2 After leveling and harrowing, the soil salinity in the 0-20cm layer decreased by 32.8%, and the salt content in the deep layer of 40-60cm did not change significantly.

[0015] In 2024, Karamay's cotton yield reached 400kg / mu based on the salt removal in the previous year. Compared with the previous year, the organic matter in the 0-20cm layer increased by 15.6%, the soil salinity in the 0-20cm layer after leveling and harrowing decreased by 18.5%, and the salt content in the 40-60cm deep layer did not change significantly. The cotton yield of Hongqi Farm reached 450kg / mu that year, and the salt removal in the cotton fiber layer was 276.8g / m 2 , 0-20cm soil, the horizontal desalination between the membranes was 63.9% compared with that under the membrane, and the salt accumulation in the 40-60cm soil was not obvious.

Claims

1. A method for removing salt and improving soil by constructing a capillary channel, characterized in that Follow these steps: Plot selection: a. Select slightly or moderately saline-alkali soil in oases in arid areas; Clear drainage channels and control groundwater level at critical depth: b. Repair and connect the drainage channel where the saline-alkali soil selected in step a is located, with an upper width of 7-10 meters, a depth of 2.5-3 meters, and a bottom width of 1-2 meters; build an observation well to dynamically track the water level and mineralization; Leveling the land, improving and fertilizing the soil (1): c. Level the land in autumn or spring, use a deep tillage shovel to deep till 60cm, spread 2000kg of decomposed animal manure and 30kg of compound fertilizer per mu, then deep till 40cm and harrow evenly; Cotton Planting: d. The cotton planter opens furrows and ridges, lays drip irrigation tape, covers the film (2), and sows seeds at one time. It uses one film, two tubes, and four rows. The film width is 1.25m. The furrow is 25cm deep and 60cm wide. It uses a drip irrigation tape with a diameter of 16mm and a large dripper flow rate of 3.0L / h. Continuous capillary channel construction: e. After completing step d, a film (2) is laid from bottom to top in the furrow, with a width of 60 cm, and a 30 cm layer of peat soil (3) is filled. Straw (4) wrapped with a cotton fiber layer (5) is inserted into the peat soil (3), with a stalk height of 25-30 cm and a insertion density of 20 stalks / m 2 , then covered with 7-10 layers of black cotton fiber layers (5), each layer 4 mm thick, the ridge furrow filling is 5-10 cm higher than the sowing ridge, wherein the straw (4) is cotton straw or reed straw; Water and fertilizer management: f. Continuous drip irrigation after sowing for 16m 3 / mu provides water for seedling emergence, which is used for washing salt inside the membrane and gathering salt between membranes, ensuring that the horizontal movement of dissolved salt water inside the membrane is greater than the vertical movement; drip irrigation during seedling stage: 7-10 days after seedling emergence, the dripping amount is 20 m 3 / mu, drip irrigation once every 7 days; drip irrigation during flowering and bolling period: drip irrigation once every 10 days, 25m 3 / mu; Drip irrigation during the full-boll period: drip irrigation every 10 days, with a drip volume of 35 m 3 / mu‌; The amount of water for each irrigation includes water for plant growth and salt water for washing under the film; During the growth period, urea was applied five times with water drops, with a total dosage of 80 kg / mu; Regular salt removal: g. Use a modified film-laying machine or manually collect the cotton fiber layer (5) regularly, collecting one layer every 15 days in the early stage; collecting one layer every 30 days in the middle stage; after the cotton ridges are sealed, all the cotton fibers are collected and taken out of the farmland at the harvest time, and the cotton fibers that absorb salt are washed and used again in the next season; Furrow ridge interchange: h. Before sowing in the next spring, the cotton stalks are crushed with a stalk beater, the plastic film on the ridges is pulled out, the peat soil and the crushed cotton stalks in the ridges are deeply plowed into the soil and returned to the field. When sowing, the ridges and furrows are interchanged, and the salt removal and soil improvement of the entire land are completed year by year.

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