A method for conserving water and raising water storage capacity in cultivated land in dry and hot river valley areas

Abstract

The present invention discloses a method for conserving water and raising the water reservoir capacity of cultivated land in arid and hot river valleys, belonging to the technical field of farmland water conservancy projects; the method comprises digging furrows and ridges along the contour lines of a plot to form W-shaped furrows and ridges; laying a degradable film, a crop straw layer and a soil cover layer in sequence at the furrow bottom; arranging water guide mechanisms at equal intervals on the soil cover layer; covering the furrow and ridge surfaces with a ground film; and establishing an evaluation standard for soil water reservoir capacity and raising capacity based on the average annual precipitation by quantitatively evaluating the treatment effect; the present invention realizes efficient utilization of soil moisture through the design of a multi-layer water-retention structure and the reasonable layout of the water guide mechanism, can effectively improve the water-retention capacity of cultivated land in arid and hot river valleys, and has good promotion and application value.

Description

Technical Field

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

[0002] The dry and hot valley area has the dual characteristics of plateau and subtropical climate. It has abundant light and heat, and the four seasons are not distinct, that is, it is mainly divided into dry season and wet season. It produces a variety of fruits and vegetables. However, the area has a prominent contradiction between water and light and heat, as well as serious soil erosion due to excessive rainfall.

[0003] The average annual precipitation in the dry and hot river valley 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 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. At present, the soil and water conservation methods of cultivated land mainly include slope conversion to terraces, contour ridge cultivation, no-tillage or minimum tillage, straw or film covering, etc. The first two methods have good soil and water conservation effects but are high in cost and not easy to promote, while the latter two are the opposite. Therefore, new technologies are still needed to develop for rainfall utilization and soil moisture conservation in dry and hot river valleys. 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 improving the water storage capacity of cultivated land in dry and hot river valleys. The method can collect surface rainwater to prevent and control surface water and soil erosion, and quickly infiltrate and store rainwater in the soil, and prevent its evaporation, thereby achieving the goal of conserving water and improving the water storage capacity of the soil. Through the combination of furrows, straw, and water pipes, rainfall utilization and soil moisture retention in dry and hot river valleys can be achieved, and the purpose of fertilizing the soil can be achieved.

[0006] The present invention adopts the following technical solutions:

[0007] A method for conserving water and increasing water storage capacity in cultivated land in a dry and hot river valley area, the method comprising the following steps:

[0008] 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;

[0009] 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.

[0010] Step S2, laying a layer of degradable film at the bottom of the furrow, and laying a crop straw layer and a soil cover layer on top of the degradable film in sequence;

[0011] The soil cover layer is formed by backfilling part of the soil on the ridge onto the crop straw layer. After backfilling, the height difference between the upper surface of the ridge and the upper surface of the soil cover layer is controlled to be 10-20 cm.

[0012] 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;

[0013] The water guide mechanism consists 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. The upper edge of the funnel is no higher than the upper surface of the soil cover layer.

[0014] Step S4, covering the upper surface of the furrow with a ground film, and opening a hole at the center of the funnel of the water guide mechanism so that the water collected on the ground film can enter the water guide pipe through the hole;

[0015] After covering the furrows and ridges with mulch, the desired crops can be planted and managed according to local common methods; after 3-5 years of cultivation, the positions of the furrows and ridges can be exchanged and the above steps can be repeated.

[0016] Furthermore, the spacing of the water guide mechanism is At the same time, the design satisfies the relationship: ;in: The spacing of the water guide mechanism, unit , 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 intensity, unit .

[0017] Furthermore, the crop straw layer is made of corn or grain straw, which is naturally air-dried and then 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 .

[0018] Furthermore, the optimal thickness of the straw layer is determined by the following formula:

[0019] ;in, is the optimal thickness of the straw layer, unit , is the average annual precipitation, unit , is the carbon-nitrogen ratio in straw;

[0020] When the optimal thickness of the straw layer When setting the thickness of the straw layer to ;

[0021] When the optimal thickness of the straw layer When setting the thickness of the straw layer to .

[0022] 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 .

[0023] 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 every quarter.

[0024] Furthermore, after the water conservation and reservoir raising treatment was carried out on the cultivated land in the dry and hot valley area, the soil water reservoir capacity was raised. The effect of water conservation and reservoir lifting was evaluated, and the soil water reservoir capacity was increased Calculation formula:

[0025] ;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:

[0026] , 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 ;

[0027] is the soil improvement depth, unit , refers to the effective depth of the combined effect of the crop straw layer and the soil cover layer, and is determined by the following formula:

[0028] Where: is the thickness of the straw layer, unit , is the thickness of soil cover, in units of , 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 ;

[0029] 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 ;

[0030] The soil water reservoir capacity increase Average annual precipitation The evaluation criteria for water conservation and reservoir lifting effects are determined jointly by soil texture and soil quality.

[0031] when hour, Not less than ;

[0032] when hour, Not less than ;

[0033] when hour, Not less than .

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The method of the present invention can collect rainwater on the ground, allowing rainwater or drip irrigation water to quickly enter the soil and be retained in the straw layer to improve the soil water reservoir capacity; mulching with mulch film can prevent the rainwater or drip irrigation water that has entered the soil from deep seepage and surface evaporation in the later period; drip irrigation can be carried out on the film, making drip irrigation 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 and improve soil fertility; the method is simple and has good operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart of a method for conserving water and increasing water storage capacity in cultivated land in arid and hot river valley areas according to the present invention;

[0037] Figure 2 It is a schematic cross-sectional view of the furrow ridge of the present invention. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0039] It should be noted that the spacing of the water guides was designed based on soil characteristics and hydrological conditions, and the layout density was optimized using mathematical models. The parameters in the formula were selected based on actual field test data; the design parameters for the straw layer fully considered material properties and environmental factors. Corn or cereal straw was selected based on its excellent water retention and widespread availability. The optimal thickness calculation method organically combines average annual precipitation and straw properties, making the design more scientific and applicable.

[0040] like Figure 1 FIG. 1 is a flow chart of a method for conserving water and increasing water storage capacity in cultivated land in a dry and hot river valley region according to the present invention, the method comprising the following steps:

[0041] 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.

[0042] During furrowing and ridge formation, each furrow corresponds to a ridge, maintaining the same width as the ridge, and soil from the furrow is transferred to the ridge. Based on the calculation requirements and evaluation criteria for soil reservoir capacity increase ΔW, and in combination with different precipitation conditions, a zoning design is implemented based on the average annual precipitation P: for areas with P < 400mm, the furrow-ridge spacing is 2-2.5m; for areas with 400mm ≤ P < 600mm, the furrow-ridge spacing is 1.5-2m; and for areas with P ≥ 600mm, the furrow-ridge spacing is 1-1.5m. This spacing design helps meet the soil reservoir capacity increase ΔW requirements for different precipitation areas.

[0043] 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.

[0044] Step S2: laying a layer of degradable film on the bottom of the ridge, and laying a crop straw layer and a soil cover layer in sequence on top of the degradable film.

[0045] like Figure 2 As shown, the soil cover 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 cover layer is controlled to be 10-20 cm.

[0046] 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 .

[0047] The optimal thickness of the straw layer is determined by the following formula:

[0048] ;in, is the optimal thickness of the straw layer, unit , is the average annual precipitation, unit , is the carbon-nitrogen ratio in straw;

[0049] When the optimal thickness of the straw layer When setting the thickness of the straw layer to ;

[0050] When the optimal thickness of the straw layer When setting the thickness of the straw layer to .

[0051] Step S3: setting water guide mechanisms at equal intervals on the center line of the soil cover layer along the contour lines of the land.

[0052] The water guide mechanism consists 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.

[0053] The spacing of the water guide mechanism is At the same time, the design satisfies the relationship: ;in: The spacing of the water guide mechanism, unit , 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 intensity, unit .

[0054] 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 .

[0055] Step S4: Cover the upper surface of the furrow with a ground film, and make a hole at the center of the funnel of the water guide mechanism so that the water collected on the ground film can enter the water guide pipe through the hole.

[0056] After covering the furrows and ridges with plastic film, the desired crops can be planted and managed according to local common methods; after 3-5 years of cultivation, the positions of the furrows and ridges are exchanged and the above steps are repeated.

[0057] 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 every quarter.

[0058] After the farmland in the dry and hot valley area is treated to retain water and increase the reservoir capacity, the soil water reservoir capacity is increased. The effect of water conservation and reservoir lifting was evaluated, and the soil water reservoir capacity was increased Calculation formula:

[0059] ;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:

[0060] , 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 ;

[0061] is the soil improvement depth, unit , refers to the effective depth of the combined effect of the crop straw layer and the soil cover layer, and is determined by the following formula:

[0062] Where: is the thickness of the straw layer, unit , is the thickness of soil cover, in units of , 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 ;

[0063] 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 ;

[0064] The soil water reservoir capacity increase Average annual precipitation The evaluation criteria for water conservation and reservoir lifting effects are determined jointly by soil texture and soil quality.

[0065] when hour, Not less than ;

[0066] when hour, Not less than ;

[0067] when hour, Not less than .

[0068] 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.

[0069] The method of this embodiment is used to open furrows and ridges, with a furrow and ridge width of 60 cm, a U-shaped furrow depth of 40 cm, and a ridge height of 35 cm. The degradable film is a 0.1 mm thick corn starch-based film, and the straw layer is corn straw. The optimal thickness is calculated to be T = 20 cm, and the laying density is 4 kg / m²; the spacing between the 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 performed twice a quarter.

[0070] The first year's effectiveness evaluation is as follows: (When the straw layer density 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%.

[0071] 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 increasing water storage capacity in 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 at the bottom of the furrow, and laying a crop straw layer and a soil cover layer on top of the degradable film in sequence; The soil cover layer is formed by backfilling part of the soil on the ridge onto the crop straw layer. After backfilling, the height difference between the upper surface of the ridge and the upper surface of the soil cover layer is controlled to be 10-20 cm. The optimal thickness of the straw layer is determined by the following formula: T = 10 × (1 + log 10 P)×(1+0.1C); where T is the optimal thickness of the straw layer, in cm, P is the average annual precipitation, in mm, and C is the carbon-nitrogen ratio in the straw; 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 consists 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. The upper edge of the funnel is no higher than the upper surface of the soil cover layer. The spacing between the water guide mechanisms is between 0.3m and 5m. Step S4, covering the upper surface of the furrow with a ground film, and opening a hole at the center of the funnel of the water guide mechanism so that the water collected on the ground film can enter the water guide pipe through the hole; After 3-5 years, swap the positions of the furrows and ridges and repeat the above steps.

2. The method for conserving water and increasing water storage capacity in cultivated land in dry and hot river valley areas according to claim 1, characterized in that: The crop straw layer is made of corn or grain straw, which is naturally air-dried and then crushed and evenly laid on the degradable film; the thickness of the crop straw layer is 10-25 cm, and the laying density is 3-5 kg / m 2 The degradable film is a corn starch-based membrane containing Bacillus subtilis, with a thickness of 0.08-0.12 mm, a tensile strength of not less than 15 MPa, and an elongation at break of not less than 200%.

3. The method for conserving water and increasing water storage capacity in cultivated land in dry and hot river valley areas according to claim 2, characterized in that: The water pipe is made of PVC material, with an inner diameter of 30-50 mm and a wall thickness of 2-3 mm; the funnel is made of PP material, with an upper edge diameter of 80-120 mm.

4. The method for conserving water and increasing water storage capacity in cultivated land in arid and hot river valley areas according to claim 1, characterized in that: The method also includes maintenance steps during the farming process: regularly checking the coverage of the ground film to ensure that the coverage integrity is not less than 95%, and cleaning the water pipes and funnels at least once every quarter.

5. The method for conserving water and increasing water storage capacity in cultivated land in dry and hot river valley areas according to claim 4, characterized in that: After water conservation and reservoir enhancement treatment was carried out on cultivated land in the dry and hot valley area, the water conservation and reservoir enhancement effect was evaluated based on the soil water reservoir capacity increase ΔW. The soil reservoir capacity increase ΔW was calculated using the following formula: ΔW = (α / 100) × β × γ × 1000; where α is the porosity of the crop straw layer, which represents the looseness and water storage capacity of the straw layer and is calculated by the following formula: α=[1-(ρb / ρs)]×100%, where ρb is the bulk density of the straw layer, in g / cm 3 , ρs is the density of straw particles, unit is g / cm 3 When the straw layer density is 3kg / m 2 When the straw layer density is 5kg / m 2 When , the value range of α is 55%-65%; β is the soil improvement depth, in meters, which refers to the effective depth of the combined effect of the crop straw layer and the soil cover layer, and is determined by the following formula: β = h1 + k × h2 Where: h1 is the thickness of the straw layer, in meters; h2 is the thickness of the soil cover layer, in meters; k is the depth influence coefficient, which is related to soil texture and ranges from 0.6 to 0.8; when the soil clay content is greater than 30%, k is 0.6 to 0.7; when the soil clay content is ≤30%, k is 0.7 to 0.8; γ is the coefficient of change of soil bulk density, which reflects the degree of soil structure improvement and has a value range of 0.1-0.

3. In the first year of treatment, γ is 0.1-0.15; in the second year of treatment, γ is 0.15-0.2; in the third year and thereafter, γ is 0.2-0.3; The soil water reservoir capacity increase ΔW is determined by the average annual precipitation P and soil texture. The evaluation criteria for water conservation and reservoir increase are: When P < 400 mm, ΔW shall not be less than 100 mm; When 400mm≤P<600mm, ΔW shall not be less than 150mm; When P≥600mm, ΔW shall not be less than 200mm.

Images