Dry and hot valley area cultivated land water retention and reservoir lifting method

Abstract

The invention discloses a water retention and reservoir lifting method for cultivated land in a dry and hot valley area, and belongs to the technical field of irrigation and water conservancy engineering. The method comprises the following steps: ditching and ridging along a plot contour line to form W-shaped furrows and ridges; a degradable film, a crop straw layer and a soil covering layer are sequentially laid at the ditch bottom; water guide mechanisms are arranged on the soil covering layer at equal intervals; covering the surfaces of the furrows and ridges with plastic films; quantitative evaluation is carried out on the treatment effect, and a soil reservoir capacity increase amount evaluation standard based on the annual average precipitation amount is established; through the multi-layer water retention structure design and reasonable arrangement of the water guide mechanism, efficient utilization of soil moisture is achieved, the water retention capacity of the cultivated land in the dry and hot valley area can be effectively improved, and good application and popularization value is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of farmland water conservancy projects, and in particular to a method for conserving water and raising the reservoir of cultivated land in dry and hot river valley areas. Background Art

[0002] The dry and hot river valley area has the dual characteristics of plateau and southern subtropical climate, with abundant light and heat, and no distinct four seasons, that is, it is mainly divided into dry season and wet season. It produces a variety of fruits and vegetables. However, there is a prominent contradiction between water and light and heat, as well as serious soil erosion due to excessively concentrated rainfall.

[0003] The average annual precipitation in the dry and hot river valley area is about 600 mm, while the average annual potential evaporation is around 3200 mm. There is basically no rainfall for more than 60% of the time in a year, and the soil moisture content is below the wilting humidity for 7 to 8 months. The continuous drought in winter and spring is particularly obvious. The annual average accumulated temperature ≥10℃ exceeds or approaches 8000℃. Therefore, the soil in the non-irrigated farmland in the dry and hot river valley area is extremely dry, and natural ecological restoration and soil and water conservation ecological construction are extremely difficult.

[0004] Therefore, regional water resource utilization and soil water conservation are particularly important; the current soil and water conservation methods for cultivated land mainly include slope conversion to terraces, contour ridge farming, no-till or minimum tillage, straw or film covering, etc. The first two methods have good soil and water conservation effects but are costly and not easy to promote, while the latter two are the opposite; therefore, new technologies for rainfall utilization and soil moisture conservation in dry and hot river valleys still need to be developed. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for conserving water and raising the water reservoir of cultivated land in arid and hot river valley areas, which can not only collect surface rainwater to prevent and control surface soil and water loss, and quickly infiltrate and store rainwater in the soil, but also prevent its evaporation, thereby achieving the goal of conserving water and raising the water reservoir of the soil. Through the combination of furrows, ridges, straw, and water pipes, rainfall utilization and soil moisture retention in the arid and hot river valley areas can be achieved, and the purpose of fertilizing the soil can be achieved.

[0006] The present invention adopts the following technical solutions: A method for conserving water and raising water storage capacity in cultivated land in arid and hot valley areas, the method comprising the following steps: Step S1, furrowing and ridge-forming along the contour lines of the plot to form a plurality of furrows and ridges distributed at equal intervals, wherein the cross section of the furrows and ridges is W-shaped; When furrowing and ridge forming, each furrow corresponds to a ridge, the width of the furrow and the ridge are kept consistent, and the soil in the furrow is transferred to the ridge.

[0007] Step S2, laying a layer of degradable film on the bottom of the furrow, and laying a crop straw layer and a soil covering layer on top of the degradable film in sequence; The soil covering layer is formed by backfilling part of the soil on the ridge onto the crop straw layer, and after backfilling, the height difference between the upper surface of the ridge and the upper surface of the soil covering layer is controlled to be 10-20 cm.

[0008] Step S3, arranging water guide mechanisms at equal intervals on the center line of the soil cover layer along the contour lines of the plot; The water guide mechanism is composed of a water guide pipe and a funnel connected to the top of the water guide pipe. The water guide mechanism is inserted into the ditch through the bottom end of the water guide pipe, ensuring that the bottom end of the water guide pipe passes through the soil cover layer and reaches the crop straw layer, and the upper edge of the funnel is not higher than the upper surface of the soil cover layer; Step S4, covering the upper surface of the furrow with a ground film, and opening a hole at the center of the funnel mouth of the water guide mechanism, so that the collected water on the ground film can enter the water guide pipe through the opening; After the furrows and ridges are covered with plastic film, the desired crops can be planted and managed according to the usual local methods; after 3-5 years of cultivation, the positions of the furrows and ridges can be exchanged and the above steps can be repeated.

[0009] Furthermore, the spacing of the water guide mechanism is At the same time, the design satisfies the relationship: ;in: is the spacing of the water guide mechanism, in units , is the saturated hydraulic conductivity of the soil cover layer, in units , is the height difference between groundwater level and ground surface, in units , D is the effective depth of soil, unit , is the design infiltration strength, unit .

[0010] Furthermore, the crop straw layer is made of corn or grain straw, which is naturally air-dried and crushed, and evenly laid on the degradable film; the thickness of the crop straw layer is , the laying density is The degradable film is a corn starch-based film containing Bacillus subtilis, with a thickness of , tensile strength not less than , elongation at break not less than .

[0011] Furthermore, the optimal thickness of the straw layer is determined by the following formula: ;in, is the optimal thickness of the straw layer, in units , is the average annual precipitation, in units , is the carbon-nitrogen ratio in straw; When the optimal thickness of the straw layer When setting the thickness of the straw layer to ; When the optimal thickness of the straw layer When setting the thickness of the straw layer to .

[0012] Furthermore, the water pipe is made of PVC and has an inner diameter of , wall thickness The funnel is made of PP material, and the upper edge diameter is .

[0013] Furthermore, the method also includes a maintenance step during the farming process: regularly checking the coverage of the ground film to ensure that the coverage integrity is not less than , clean the water pipes and funnels at least once a quarter.

[0014] Furthermore, after water conservation and reservoir lifting treatment was carried out on the cultivated land in the dry and hot valley area, the soil water reservoir capacity was increased. The effect of water conservation and reservoir lifting is evaluated. The soil water reservoir capacity is increased Calculation formula: ;in, is the porosity of the crop straw layer, which characterizes the looseness and water storage capacity of the straw layer and is calculated by the following formula: , where is the bulk density of the straw layer, unit , is the density of straw particles, unit ; When the straw layer laying density is hour, The value range is ; When the straw layer laying density is hour, The value range is ; is the soil improvement depth, in units , refers to the effective depth of the crop straw layer and the soil cover layer, which is determined by the following formula: Where: is the thickness of the straw layer, in units , is the soil cover thickness, in units , is the depth influence coefficient, which is related to soil texture and has a value range of ; When the soil clay content hour, Value , when the soil clay content hour, Value ; is the soil bulk density variation coefficient, which reflects the degree of soil structure improvement and has a value range of , among which, the processing year, Value ; Processing year 2, Value ; Processing for the 3rd year and beyond, Value ; The soil water reservoir capacity increase Average annual precipitation Determined by soil texture, the evaluation criteria for water conservation and reservoir lifting effect are: when hour, Not less than ; when hour, Not less than ; when hour, Not less than .

[0015] Compared with the prior art, the present invention has the following beneficial effects: The method of the present invention can collect rainwater on the ground, allow rainwater or drip irrigation water to quickly enter the soil body, and maintain it in the straw layer to improve the soil water reservoir capacity; mulching with mulch film can prevent the rainwater or drip irrigation water that enters the soil from deep seepage and surface evaporation in the later period; drip irrigation can be carried out on the film, making drip irrigation easier and more feasible; deep burial of straw can not only improve and maintain the soil water reservoir, but also improve and maintain the soil organic matter content to improve soil fertility; the method is simple and has good operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of a method for conserving water and raising water storage capacity in cultivated land in arid and hot valley areas of the present invention; Figure 2 It is a schematic cross-sectional view of the furrow ridge of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be noted that the spacing design of the water guide mechanism takes into account soil characteristics and hydrological conditions, and the layout density is optimized through mathematical models. The selection of each parameter in the formula is based on actual field test data; the design parameters of the straw layer fully consider material properties and environmental factors. Corn or cereal straw is selected based on its good water retention performance and general availability; the calculation method of the optimal thickness organically combines the average annual precipitation and the properties of straw, making the design more scientific and applicable.

[0019] like Figure 1 As shown, it is a flow chart of a method for conserving water and raising water storage capacity in cultivated land in arid and hot valley areas of the present invention, and the method comprises the following steps: Step S1, digging furrows and forming ridges along the contour lines of the plot to form a plurality of furrows and ridges distributed at equal intervals, wherein the cross section of the furrows and ridges is W-shaped.

[0020] When trenching and ridge-forming, each trench corresponds to a ridge, and the width of the trench and the ridge is consistent, and the soil in the trench is transferred to the ridge. According to the calculation requirements and evaluation criteria of the soil reservoir capacity increase ΔW, combined with different precipitation conditions, the zoning design is based on the average annual precipitation P: in the area of ​​P < 400mm, the spacing between the trench and the ridge is 2-2.5m; in the area of ​​400mm≤P<600mm, the spacing between the trench and the ridge is 1.5-2m; in the area of ​​P≥600mm, the spacing between the trench and the ridge is 1-1.5m; such spacing design helps to meet the soil reservoir capacity increase ΔW requirements corresponding to different precipitation areas.

[0021] The specifications are adjusted according to the soil texture. When the soil clay content is greater than 30%, the U-shaped ditch depth is 35-40cm; the ditch bottom width is 50-55cm; the depth influence coefficient k is 0.6-0.7; when the soil clay content is ≤30%, the U-shaped ditch depth is 40-45cm; the ditch bottom width is 55-60cm; the depth influence coefficient k is 0.7-0.8; the ditch bottom cross-section must strictly maintain a U-shape, the ditch wall slope is controlled at 70-75°, and the ditch bottom flatness error does not exceed ±2cm. These requirements ensure that the subsequent degradable film and straw layer can be stably laid.

[0022] Step S2, laying a layer of degradable film on the bottom of the ridge, and laying a crop straw layer and a soil covering layer in sequence on top of the degradable film.

[0023] like Figure 2As shown, the soil covering layer is formed by backfilling part of the soil on the ridge onto the crop straw layer, and after backfilling, the height difference between the upper surface of the ridge and the upper surface of the soil covering layer is controlled to be 10-20 cm.

[0024] The crop straw layer is made of corn or grain straw, which is naturally air-dried and crushed, and evenly laid on the degradable film; the thickness of the crop straw layer is , the laying density is The degradable film is a corn starch-based film containing Bacillus subtilis, with a thickness of , tensile strength not less than , elongation at break not less than .

[0025] The optimal thickness of the straw layer is determined by the following formula: ;in, is the optimal thickness of the straw layer, in units , is the average annual precipitation, in units , is the carbon-nitrogen ratio in straw; When the optimal thickness of the straw layer When setting the thickness of the straw layer to ; When the optimal thickness of the straw layer When setting the thickness of the straw layer to .

[0026] Step S3, arranging water guiding mechanisms at equal intervals on the center line of the soil cover layer along the contour lines of the plot.

[0027] The water guiding mechanism consists of a water guiding pipe and a funnel connected to the top of the water guiding pipe. The water guiding mechanism is inserted into the ditch through the bottom end of the water guiding pipe, ensuring that the bottom end of the water guiding pipe passes through the soil covering layer and reaches the crop straw layer, and the upper edge of the funnel is not higher than the upper surface of the soil covering layer.

[0028] The spacing of the water guide mechanism is At the same time, the design satisfies the relationship: ;in: is the spacing of the water guide mechanism, in units , is the saturated hydraulic conductivity of the soil cover layer, in units , is the height difference between groundwater level and ground surface, in units , D is the effective depth of soil, unit , is the design infiltration strength, unit .

[0029] The water pipe is made of PVC material and its inner diameter is , wall thickness The funnel is made of PP material, and the upper edge diameter is .

[0030] Step S4, covering the upper surface of the furrow with a ground film, and opening a hole at the center of the funnel mouth of the water guide mechanism, so that the collected water on the ground film can enter the water guide pipe through the opening.

[0031] After the furrows and ridges are covered with plastic film, the desired crops can be planted and managed according to the usual local methods; after 3-5 years of cultivation, the positions of the furrows and ridges are exchanged and the above steps are repeated.

[0032] The method also includes a maintenance step during the farming process: regularly checking the coverage of the ground film to ensure that the coverage integrity is not less than , clean the water pipes and funnels at least once a quarter.

[0033] After the farmland in the dry and hot valley area was treated with water conservation and reservoir lifting, the soil water reservoir capacity was raised. The effect of water conservation and reservoir lifting is evaluated. The soil water reservoir capacity is increased Calculation formula: ;in, is the porosity of the crop straw layer, which characterizes the looseness and water storage capacity of the straw layer and is calculated by the following formula: , where is the bulk density of the straw layer, unit , is the density of straw particles, unit ; When the straw layer laying density is hour, The value range is ; When the straw layer laying density is hour, The value range is ; is the soil improvement depth, in units , refers to the effective depth of the crop straw layer and the soil cover layer, which is determined by the following formula: Where: is the thickness of the straw layer, in units , is the soil cover thickness, in units , is the depth influence coefficient, which is related to soil texture and has a value range of ; When the soil clay content hour, Value , when the soil clay content hour, Value ; is the soil bulk density variation coefficient, which reflects the degree of soil structure improvement and has a value range of , among which, the processing year, Value ; Processing year 2, Value ; Processing for the 3rd year and beyond, Value ; The soil water reservoir capacity increase Average annual precipitation Determined by soil texture, the evaluation criteria for water conservation and reservoir lifting effect are: when hour, Not less than ; when hour, Not less than ; when hour, Not less than .

[0034] Taking the cultivated land in a dry and hot river valley as an example, the basic conditions of the area are: average annual precipitation P = 450 mm, plot area 2 hectares, soil clay content 25%, height difference between groundwater level and surface H = 3 m, and effective soil depth D = 0.8 m.

[0035] The method of this embodiment is used to dig furrows and ridges, with a furrow and ridge width of 60 cm, a U-shaped furrow depth of 40 cm, a ridge height of 35 cm, a 0.1 mm thick corn starch-based film as the degradable film, and corn straw as the straw layer. The optimal thickness is calculated to be T = 20 cm, and the laying density is 4 kg / m²; the spacing between water guide mechanisms is L = 2 m, and a PVC water guide pipe with an inner diameter of 40 mm and a funnel diameter of 100 mm is selected; a 0.01 mm thick ground film is used, and inspection and maintenance are carried out twice a quarter.

[0036] The first year's effectiveness evaluation is as follows: (When the laying density of straw layer is 4kg / m²); , γ is 0.15, , in line with the standard requirement of ΔW not less than 150mm when 400mm≤P<600mm; our actual measurement of the plot showed that the soil moisture content increased by 35%, crop yield increased by 25%, irrigation water was saved by 30%, and soil organic matter content increased by 0.8%.

[0037] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for conserving water and raising the reservoir of cultivated land in dry and hot river valleys, characterized in that: The method comprises the following steps: Step S1, furrowing and ridge-forming along the contour lines of the plot to form a plurality of furrows and ridges distributed at equal intervals, wherein the cross section of the furrows and ridges is W-shaped; When furrowing and ridge forming, each furrow corresponds to a ridge, the width of the furrow and the ridge are kept consistent, and the soil in the furrow is transferred to the ridge; Step S2, laying a layer of degradable film on the bottom of the furrow, and laying a crop straw layer and a soil covering layer on top of the degradable film in sequence; The soil covering layer is formed by backfilling part of the soil on the ridge onto the crop straw layer, and after backfilling, the height difference between the upper surface of the ridge and the upper surface of the soil covering layer is controlled to be 10-20 cm; Step S3, arranging water guide mechanisms at equal intervals on the center line of the soil cover layer along the contour lines of the plot; The water guide mechanism is composed of a water guide pipe and a funnel connected to the top of the water guide pipe. The water guide mechanism is inserted into the ditch through the bottom end of the water guide pipe, ensuring that the bottom end of the water guide pipe passes through the soil cover layer and reaches the crop straw layer, and the upper edge of the funnel is not higher than the upper surface of the soil cover layer; Step S4, covering the upper surface of the furrow with a ground film, and opening a hole at the center of the funnel mouth of the water guide mechanism, so that the collected water on the ground film can enter the water guide pipe through the opening; After 3-5 years, swap the positions of the furrows and ridges and repeat the above steps.

2. The method for conserving water and raising the reservoir of cultivated land in dry and hot river valley areas according to claim 1 is characterized in that: The spacing of the water guide mechanism is between.

3. The method for conserving water and raising the reservoir of cultivated land in dry and hot river valley areas according to claim 2 is characterized in that: The crop straw layer is made of corn or grain straw, which is naturally air-dried and crushed, and evenly laid on the degradable film; the thickness of the crop straw layer is , the laying density is The degradable film is a corn starch-based film containing Bacillus subtilis, with a thickness of , tensile strength not less than , elongation at break not less than .

4. The method for conserving water and raising water storage capacity of cultivated land in dry and hot river valley areas according to claim 3 is characterized in that: The optimal thickness of the straw layer is determined by the following formula: ;in, is the optimal thickness of the straw layer, in units , is the average annual precipitation, in units , is the carbon-nitrogen ratio in straw; When the optimal thickness of the straw layer When setting the thickness of the straw layer to ; When the optimal thickness of the straw layer When setting the thickness of the straw layer to .

5. The method for conserving water and raising water storage capacity of cultivated land in dry and hot river valley areas according to claim 4, characterized in that: The water pipe is made of PVC material and its inner diameter is , wall thickness The funnel is made of PP material, and the upper edge diameter is .

6. The method for conserving water and raising water storage capacity of cultivated land in dry and hot river valley areas according to claim 1, characterized in that: The method also includes a maintenance step during the farming process: regularly checking the coverage of the ground film to ensure that the coverage integrity is not less than , clean the water pipes and funnels at least once a quarter.

7. The method for conserving water and raising water storage capacity of cultivated land in dry and hot river valley areas according to claim 6, characterized in that: After the farmland in the dry and hot valley area was treated with water conservation and reservoir lifting, the soil water reservoir capacity was raised. The effect of water conservation and reservoir lifting is evaluated. The soil water reservoir capacity is increased Calculation formula: ;in, is the porosity of the crop straw layer, which characterizes the looseness and water storage capacity of the straw layer and is calculated by the following formula: , where is the bulk density of the straw layer, unit , is the density of straw particles, unit ; When the straw layer laying density is hour, The value range is ; When the straw layer laying density is hour, The value range is ; is the soil improvement depth, in units , refers to the effective depth of the crop straw layer and the soil cover layer, which is determined by the following formula: Where: is the thickness of the straw layer, in units , is the soil cover thickness, in units , is the depth influence coefficient, which is related to soil texture and has a value range of ; When the soil clay content hour, Value , when the soil clay content hour, Value ; is the soil bulk density variation coefficient, which reflects the degree of soil structure improvement and has a value range of , among which, the processing year, Value ; Processing year 2, Value ; Processing for the 3rd year and beyond, Value ; The soil water reservoir capacity increase Average annual precipitation Determined by soil texture, the evaluation criteria for water conservation and reservoir lifting effect are: when hour, Not less than ; when hour, Not less than ; when hour, Not less than .

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