Method suitable for water storage, soil moisture conservation, fertilization and carbon sequestration of dry farmland in semi-arid region

Abstract

The invention discloses a method suitable for water storage, soil moisture conservation, fertilization and carbon sequestration of a dry farmland in a semi-arid region, and belongs to the technical field of agricultural ecological engineering. According to the method, efficient interception of water resources in the dry farmland in the semi-arid region, improvement of soil fertility and enhancement of carbon sequestration capacity are achieved through the synergistic effect of water storage and soil moisture conservation project construction (water storage tank + arc retaining wall), biological fertilization system implementation (three-layer plant community + microbial inoculum-slow release fertilizer) and carbon sequestration regulation and control technology (green returning to field + no-tillage). Specifically, the runoff retaining rate is increased by 40% or above, and the soil water content is increased by 25%; the soil organic matter content is increased by 0.3% annually, and the microbial activity is improved by 30%; the soil carbon reserve is increased by 15% or above in three years, and the crop yield is increased by 15%-20% per year. The method overcomes the defect of single function in the prior art, is suitable for loess plateau, Inner Mongolia and other semi-arid region dry farmland, has both ecological benefits and economic benefits, and has wide application prospects.

Description

Technical Field

[0001] This invention relates to the field of agricultural ecological engineering technology, and in particular to a method suitable for water storage, moisture conservation, fertilization, and carbon sequestration in dryland fields in semi-arid regions. Background Technology

[0002] Semi-arid regions, as one of the most important areas for global agricultural production, have long faced core problems such as water scarcity, soil degradation, and weak carbon sequestration capacity in their dryland systems, severely restricting sustainable agricultural development and ecological environment improvement. The region experiences uneven spatial and temporal distribution of annual precipitation, with 60%-80% concentrated in summer and mostly in the form of torrential rains. This results in slope runoff loss rates as high as 30%-50%, and the effective soil moisture content is consistently below the critical value for crop water requirements. Simultaneously, long-term extensive farming, single-fertilizer application, and over-cultivation have damaged soil structure, increasing bulk density to 1.4-1.6 g / cm³. 3 Porosity decreased to below 40%, the annual degradation rate of soil organic matter reached 1.2%-1.8%, and the carbon sequestration function continued to decline.

[0003] Existing technologies address these issues primarily through single-function measures, failing to provide a systematic solution. While traditional full-film double-ridge furrow sowing technology can increase moisture retention to over 60%, long-term use easily leads to decreased soil permeability, soil compaction exceeding 40% in the topsoil, and residual film pollution rates climbing annually to 30 kg / hm². 2 The above points are as follows: Although conventional fertilizer application (such as nitrogen fertilizer alone or nitrogen-phosphorus compound fertilizer) can increase crop yield in the short term, the nitrogen utilization rate is only 30%-35%, and it cannot replenish soil organic matter. Instead, it exacerbates the imbalance of soil microbial community, and the soil carbon pool decreases by an average of 0.5%-0.8% per year. Some carbon sequestration technologies (such as direct straw return to the field) are prone to slow straw decomposition due to insufficient soil moisture in semi-arid areas. This not only fails to improve soil fertility in time, but may also cause seedling gaps and row breaks in the crop seedling stage.

[0004] Therefore, there is an urgent need to develop a comprehensive technology that integrates engineering water storage, bio-fertilization, and carbon sequestration regulation. Through the synergistic effect of multiple measures, this technology can achieve the integrated goals of efficient water retention, targeted improvement of soil quality, and enhanced carbon sequestration function in dryland areas of semi-arid regions, providing technical support for the sustainable development of agricultural ecosystems in these areas. Summary of the Invention

[0005] The purpose of this invention is to provide a method suitable for water storage, moisture conservation, fertilization, and carbon sequestration in dryland fields in semi-arid regions, in order to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a method for water storage, moisture conservation, fertilization, and carbon sequestration in dryland fields in semi-arid regions, characterized by comprising the following steps:

[0008] Water storage and moisture conservation project construction: On the slope, dig a water storage trench 50-80cm wide and 80-150cm deep along the contour line. Lay a straw buffer layer with a thickness of ≥30cm at the bottom of the trench. Backfill the sides of the trench with a mixture of straw and organic fertilizer to form a water-retaining matrix layer. Set up an arc-shaped retaining wall above the trench. The retaining wall is made by cutting retired wind turbine blades. Runoff guide holes with filters are opened at the top of the retaining wall.

[0009] Bio-fertilization system implementation: A three-layer planting structure of trees-shrubs-herbs is adopted. The trees are selected as sea buckthorn or caragana, the shrubs are selected as amorpha fruticosa, and the herbs are alfalfa or ice grass. The compound microbial agent and granular slow-release fertilizer are mixed at a mass ratio of 1:5 and buried around the planting hole through the grid frame or spread in the herb area.

[0010] Carbon sequestration and regulation technology: Every autumn, sweet potatoes are plowed into the soil for green mulch and returned to the field, with a plowing depth of 15-20cm and a plowing volume of 30-45t / hm². 2 Implement no-till or reduced-tillage management, with ≤2 tillages per year and localized deep loosening every 2-3 years.

[0011] 2. The method according to claim 1, characterized in that, in the water storage and moisture conservation project, the spacing between water storage tanks is adjusted according to the slope: when the slope is 5°-10°, the tank spacing is 3-4m; when the slope is 10°-15°, the tank spacing is 2-3m; the height of the arc-shaped retaining wall is 40-60cm, the radius of curvature of the arc surface is 80-100cm, and it is fixed by a concrete base with a base burial depth ≥20cm; the diameter of the runoff guide hole is 8-12cm, the hole spacing is 30-40cm, and an 80-100 mesh filter screen is installed in the hole.

[0012] Preferably, the compound microbial agent includes Bacillus subtilis and Bacillus licheniformis.

[0013] Preferably, the viable count of Bacillus subtilis in the compound microbial agent is ≥2.0 × 10⁻⁶. 9 CFU / g, viable count of Bacillus licheniformis ≥1.0×10⁻⁶ 9 CFU / g.

[0014] Preferably, the granular slow-release fertilizer uses modified starch and polyvinyl alcohol as coating materials.

[0015] Preferably, in the three-layer planting structure of trees-shrubs-herbs, the row spacing of trees is 4-5m and the plant spacing is 2-3m, with 800-1200 trees planted per hectare; the row spacing of shrubs is 2-3m and the plant spacing is 1-1.5m, with 2500-3500 shrubs planted per hectare; and the seeding rate of herbs is 15-20 kg / hm². 2 It can be broadcast in a mixed or unicast manner.

[0016] Preferably, the green manure application is carried out in September or October each year, followed by irrigation once with a water volume of 20-30 cubic meters. 3 / hm 2 Local deep loosening depth is 30-40cm.

[0017] Preferably, the top of the water storage tank of the water storage and moisture conservation project is covered with a shade net with a shading rate of 40%-50%, and sand fern is planted on both sides of the tank to form a soil stabilization and protection belt.

[0018] The present invention discloses the following technical effects:

[0019] Significantly improved water storage efficiency: Through the synergistic effect of water storage troughs and curved retaining walls, the runoff interception rate on slopes is increased by more than 40%, which is more than twice that of traditional planting methods (runoff interception rate ≤20%); the soil moisture content in the 0-100cm soil layer increases by 25%, with the most significant increase in soil moisture content during the sowing period (spring), which can meet the water requirements of crop seedlings and reduce the impact of drought stress on crop growth.

[0020] Targeted improvement of soil fertility: After the implementation of the bio-fertilization system, the soil organic matter content increases by an average of 0.3% per year. After three years, the soil organic matter content can be increased from the initial 1.0%-1.2% to 1.8%-2.0%. Soil microbial activity increases by 30%, with the number of bacteria and fungi increasing by 25%-35% and 15%-25% respectively. Soil urease and phosphatase activities increase by 20%-30%, nutrient conversion efficiency is significantly enhanced, and crop nitrogen fertilizer utilization rate increases from 30%-35% to 45%-50%.

[0021] Carbon sequestration capacity continues to be enhanced: the synergistic effect of green mulch and no-till measures increases soil organic carbon storage by 5%-8% annually, and carbon storage increases by more than 15% after three years; at the same time, the biomass of tree-shrub-herbaceous plant communities increases by 10%-15% annually, and vegetation carbon fixation increases by 8%-12%, thus achieving synergistic enhancement of the carbon sequestration function of the soil-vegetation system.

[0022] Win-win for both ecology and economy: After the implementation of this method, the soil erosion modulus on slopes is reduced by more than 50%, effectively curbing soil degradation; crop yields increase by an average of 15%-20% annually, and the quality of agricultural products is improved, such as wheat protein content increasing by 1.0%-1.5% and corn starch content increasing by 0.8%-1.2%; at the same time, the resource utilization of retired wind turbine blades reduces engineering costs, lowering the cost by 30%-40% compared to traditional concrete retaining walls, demonstrating good economic feasibility and ecological benefits. Detailed Implementation

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0025] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0026] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0027] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0028] Example 1: Application on 5°-15° slopes in the Loess Plateau region

[0029] Site Overview: The experimental site is located in a county in the central part of the Loess Plateau, a typical semi-arid region with an annual precipitation of 400-450 mm, concentrated in July to September. The soil type is loess loess, with an initial soil organic matter content of 1.2% and a soil bulk density of 1.45 g / cm³. 3 The soil moisture content (at the sowing period) in the 0-100cm soil layer was 8%-10%; the experimental area was 1 hm². 2 The slope ranges from 5° to 15°, and the previous crop was wheat.

[0030] Implementation steps

[0031] Water storage and moisture conservation project construction: Water storage trenches are excavated along contour lines, 60cm wide and 120cm deep. The trench spacing is adjusted according to the slope: 3.5m spacing in areas with a slope of 5°-10°, and 2.5m spacing in areas with a slope of 10°-15°. Crushed corn stalks (5-8cm long) are laid at the bottom of the trenches, 35cm thick, with a compacted density of 0.35g / cm³. 3 The sides of the trench are backfilled with a mixture of corn stalks and well-rotted sheep manure (volume ratio 3:1), compacted in layers, each layer 18cm thick. The arched retaining wall is made from cut retired wind turbine blades, 50cm high with a 90cm radius of curvature, and fixed to a concrete base (25cm deep). Runoff guide holes with a diameter of 10cm and a spacing of 35cm are opened at the top of the retaining wall, with 80-mesh filters installed inside. The trench top is covered with a 45% shading net, and protective belts are formed on both sides by planting *Alternanthera philoxeroides*.

[0032] Implementation of the bio-fertilization system: A three-layer planting structure of trees, shrubs, and herbs is adopted. For trees, sea buckthorn (1.8m tall) is selected, with a row spacing of 4.5m and a plant spacing of 2.5m, resulting in 880 trees per hectare. For shrubs, Amorpha fruticosa (1.0m tall) is selected, with a row spacing of 2.5m and a plant spacing of 1.2m, resulting in 3330 shrubs per hectare. For herbs, a mixture of alfalfa and crested wheatgrass (3:1 weight ratio) is selected, with a seeding rate of 18kg / hm². 2 Compound microbial inoculant (Bacillus subtilis 2.0 × 10⁻⁶) 9 CFU / g + Bacillus licheniformis 1.0×10 9 CFU / g) and granular slow-release fertilizer (N:P:K = 1:0.5:1, slow-release period 7 months) are mixed at a mass ratio of 1:5. The application rate is 120g / tree in the grid frame (35cm×35cm×25cm) of the tree planting hole, 60g / shrub, and 25kg / hm in the herbaceous area. 2 Then it was lightly turned into soil.

[0033] Carbon sequestration and regulation technology implementation: Plant purple sweet potatoes in mid-September, and mechanically till them in late May of the following year (peak flowering period), with a tilling depth of 18cm and a tilling rate of 40t / hm². 2 After turning and compacting, water for 25m. 3 / hm 2 After green manure application, no-till management is implemented, with shallow tillage only to a depth of 12cm in the wheat sowing row during spring sowing; local deep loosening (35cm depth) is carried out once every 3 years, and soil bulk density is monitored to maintain 1.3-1.4g / cm³. 3 .

[0034] Results: After three consecutive years of implementation, the slope runoff interception rate of the experimental plot increased from 18% to 59%; the soil moisture content in the 0-100cm layer (at the sowing period) increased from 9% to 11.3%; soil organic matter content increased from 1.2% to 1.8%; soil microbial activity increased by 32%; wheat nitrogen fertilizer utilization rate increased from 33% to 48%; soil organic carbon storage increased by 15.2%; and the biomass of the sea buckthorn-Amorpha fruticosa-alfalfa community increased by an average of 13% annually. Wheat yield increased from 4500 kg / hm² before implementation. 2 Increased to 5460 kg / hm 2 The increase was 21.3%, and the protein content of wheat increased from 12.5% ​​to 14.1%, resulting in significant economic and ecological benefits.

[0035] Example 2: Application in dryland farming at 10°-15° latitude in eastern Inner Mongolia

[0036] Site Overview: The experimental site is located in a banner (county-level administrative division) in eastern Inner Mongolia, with an annual precipitation of 250-300 mm, belonging to a semi-arid to slightly arid region; the soil type is chestnut calcareous soil, with an initial soil organic matter content of 1.0% and a soil bulk density of 1.52 g / cm³. 3 The soil moisture content in the 0-100cm soil layer (at the sowing period) was 6%-7%; the experimental area was 0.8hm². 2 The slope is 10°-15° and the previous crop was corn.

[0037] Implementation steps: The water storage tank should be 50cm wide and 100cm deep, with a spacing of 2m between tanks; the straw layer at the bottom of the tank should be 30cm thick (wheat straw, 8-10cm long), with a compacted density of 0.4g / cm³. 3 The sides of the trench are backfilled with a mixture of wheat straw and well-rotted cow manure (volume ratio 3:1). The arched retaining wall is 40cm high with a radius of curvature of 80cm, and the guide holes are 8cm in diameter and spaced 30cm apart. The top of the trench is covered with a shade net with a 40% shading rate. For trees, Caragana korshinskii (1.2m tall) is selected, with a row spacing of 4m and a plant spacing of 2m, resulting in 1250 trees per hectare; for shrubs, Amorpha fruticosa (0.8m tall) is selected, with a row spacing of 2m and a plant spacing of 1m, resulting in 5000 shrubs per hectare; for herbs, Alfalfa is selected, with a seeding rate of 15kg / hm². 2 After mixing the compound microbial agent with the slow-release fertilizer, the application rate is 100g / tree for trees, 50g / tree for shrubs, and 20kg / hm² for herbaceous areas. 2 Autumn green mulch application (purple sweet potato mulch application rate: 35 t / hm²) 2 No-till management is combined with deep tillage once every 2 years (to a depth of 30cm).

[0038] Results: After three years, the runoff retention rate increased from 15% to 55%, soil moisture content (at the sowing period) increased from 6.5% to 8.2%, soil organic matter content increased from 1.0% to 1.7%, and soil bulk density decreased to 1.40 g / cm³.3 Corn yield increased from 3800 kg / hm² 2 Increased to 4560 kg / hm 2 The increase was 20%, and the corn starch content increased from 68.5% to 69.3%. This method also has good applicability in semi-arid and arid areas.

[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for water conservation, soil moisture retention, fertilization, and carbon sequestration in dryland fields in semi-arid regions, characterized in that, Includes the following steps: Water storage and moisture conservation project construction: On the slope, dig a water storage trench 50-80cm wide and 80-150cm deep along the contour line. Lay a straw buffer layer with a thickness of ≥30cm at the bottom of the trench. Backfill the sides of the trench with a mixture of straw and organic fertilizer to form a water-retaining matrix layer. Set up an arc-shaped retaining wall above the trench. The retaining wall is made by cutting retired wind turbine blades. Runoff guide holes with filters are opened at the top of the retaining wall. Bio-fertilization system implementation: A three-layer planting structure of trees-shrubs-herbs is adopted. The trees are selected as sea buckthorn or caragana, the shrubs are selected as amorpha fruticosa, and the herbs are alfalfa or ice grass. The compound microbial agent and granular slow-release fertilizer are mixed at a mass ratio of 1:5 and buried around the planting hole through the grid frame or spread in the herb area. Carbon sequestration and regulation technology: Every autumn, sweet potatoes are plowed into the soil for green mulch and returned to the field, with a plowing depth of 15-20cm and a plowing volume of 30-45t / hm². 2 Implement no-till or reduced-tillage management, with ≤2 tillages per year and localized deep loosening every 2-3 years.

2. The method according to claim 1, characterized in that, In the water storage and moisture conservation project, the spacing between water storage tanks is adjusted according to the slope: when the slope is 5°-10°, the tank spacing is 3-4m; when the slope is 10°-15°, the tank spacing is 2-3m; the height of the arc-shaped retaining wall is 40-60cm, the radius of curvature of the arc surface is 80-100cm, and it is fixed by a concrete base with a base burial depth ≥20cm; the diameter of the runoff guide hole is 8-12cm, the hole spacing is 30-40cm, and an 80-100 mesh filter screen is installed in the hole.

3. The method according to claim 1, characterized in that, The compound microbial agent includes Bacillus subtilis and Bacillus licheniformis.

4. The method according to claim 1, characterized in that, The granular slow-release fertilizer uses modified starch and polyvinyl alcohol as coating materials.

5. The method according to claim 1, characterized in that, In the described three-layer planting structure of trees, shrubs, and herbs, the row spacing for trees is 4-5m and the plant spacing is 2-3m, with 800-1200 trees planted per hectare; the row spacing for shrubs is 2-3m and the plant spacing is 1-1.5m, with 2500-3500 shrubs planted per hectare; and the sowing rate for herbs is 15-20 kg / hm². 2 It can be broadcast in a mixed or unicast manner.

6. The method according to claim 1, characterized in that, The process of plowing and returning green manure to the field is carried out in September or October each year, followed by irrigation once with 20-30 cubic meters of water. 3 / hm 2 Local deep loosening depth is 30-40cm.

7. The method according to claim 1, characterized in that, The water storage and moisture conservation project covers the top of the water storage tank with a shading net with a shading rate of 40%-50%, and plantes sand fern on both sides of the tank to form a soil stabilization and protection belt.