Salt control, recarburization and fertility improvement integrated method for soil in coastal water-deficient saline-alkaline area
By excavating water storage ditches and underground/open ditches in water-scarce saline-alkali areas along the coast, combined with brackish water irrigation and straw return to the field, and adopting a farming system that combines active and stable carbon sources, the problem of water scarcity and the disconnect between salt control and fertilization in soil improvement in water-scarce saline-alkali areas along the coast has been solved. This has achieved rapid salt reduction and carbon increase and improved soil fertility, and is economically feasible and long-term effective.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-05
- Publication Date
- 2026-03-10
AI Technical Summary
Soil improvement in water-scarce saline-alkali areas faces challenges such as water scarcity, high engineering costs, a disconnect between salt control and fertilization, and slow improvement of soil organic matter, making it difficult to achieve rapid and efficient saline-alkali land improvement.
By digging water storage ditches between adjacent fields, combining underground pipes or open ditches, using slightly saline water for supplemental irrigation, and combining straw return to the field with composting agents, a three-dimensional salt control and carbon increase system is constructed using a combination of active and stable carbon sources, thereby achieving efficient water resource utilization and rapid improvement of soil organic matter.
It has achieved rapid salinity reduction and carbon increase in saline-alkali land, improved soil structure and fertility, increased crop yield, reduced dependence on external freshwater and high-cost engineering projects, and is economically feasible and sustainable.
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Figure CN121621077A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of soil improvement technology, specifically to an integrated method for controlling salt content, increasing carbon content, and improving fertility in water-scarce and saline-alkali soils in coastal areas. Background Technology
[0002] Coastal saline-alkali soil is an important reserve of arable land, and its improvement and utilization are of great significance to ensuring food security. Coastal saline-alkali areas suffer from extreme scarcity of freshwater resources, but have concentrated summer rainfall and relatively abundant surface brackish water. This unique spatial and temporal distribution of water resources presents the region with a severe challenge in saline-alkali land management: "water shortages for spring sowing, wasted summer rainwater, and upward flow of salt in autumn."
[0003] In existing technologies, the remediation of coastal saline-alkali land mainly relies on two models: First, the "drainage-based" engineering model, which involves excavating open ditches or laying underground pipes to drain soil salts with water. However, this model requires sufficient freshwater for leaching, and its effectiveness is limited in water-scarce areas due to the inability to meet this condition, and the engineering costs are also high. Second, the "large-scale water-to-salt" agronomic model, which consumes a large amount of freshwater resources, is difficult to promote in water-scarce areas, and is prone to causing environmental problems such as deep seepage and nutrient loss.
[0004] Furthermore, existing technologies typically treat salt control and soil fertility improvement as two separate processes, lacking a systematic and synergistic design. Conventional soil fertility improvement measures are slow to take effect under saline-alkali stress and are difficult to rapidly improve soil fertility. In particular, the lack of carbon source material formulations tailored to the characteristics of saline-alkali soils and corresponding tillage systems leads to slow improvement in soil organic matter and deterioration in soil quality, making it difficult to effectively improve the topsoil structure.
[0005] Therefore, there is an urgent need in this field for an integrated technology that can adapt to the water-scarce characteristics of coastal areas, organically combine efficient water resource utilization, three-dimensional salt control and rapid carbon enrichment, so as to achieve synergistic improvement of saline-alkali farmland fertility restoration and productivity enhancement at low cost and high efficiency. Summary of the Invention
[0006] To address the above problems, this invention provides an integrated method for controlling salinity, increasing carbon content, and improving fertility in water-scarce saline-alkali soils in coastal areas, specifically including the following steps:
[0007] Step one: Dig water storage ditches between adjacent fields. The ditches should be 2 m wide at the bottom, 4 m wide at the top, and 2 m deep. A waterproof plastic sheet should be laid inside the ditches to prevent salt exchange between the collected rainwater and groundwater. The ditches collect summer rainfall for irrigation during spring and autumn crop sowing and key growth periods (including the jointing-heading stage of wheat and the tasseling-silking stage of corn). Simultaneously, during crop growth, slightly saline surface water can be used for supplemental irrigation, maximizing the conservation and substitution of freshwater resources.
[0008] Preferably, the supplementary irrigation operation is as follows: winter wheat is supplemented with slightly saline water with a mineralization degree ≤3 g / L once during the spring jointing stage, and summer maize is supplemented with slightly saline water with a mineralization degree ≤2 g / L 1-2 times during the middle and late growth stages.
[0009] Step two involves controlling the groundwater level through engineering measures and combining this with differentiated straw return to the field as an ecological agronomical approach to construct a three-dimensional salt control system integrating engineering, ecology, and agronomy. Specifically, in fields suitable for laying underground pipes, 20-40 m spacing and 1.5-1.7 m burial depth are used; in fields where underground pipe laying is not feasible, open ditches are dug with a spacing of 50-60 m, a depth of 1.5-2.5 m, a bottom width of 1-2 m, and an top width of 3-4 m. Corn straw is pulverized in situ to 3-5 cm and sprayed with 2-3 kg / mu of composting agent. This is then turned over to a 25-30 cm soil layer 7-15 days before wheat sowing, forming a straw interlayer. This process is repeated every 2-3 years. Wheat straw is pulverized in situ to 3-5 cm, evenly spread on the surface, and sprayed with 2-3 kg / mu of composting agent, followed immediately by no-till corn sowing.
[0010] Preferably, the composting agent is a compound microbial agent containing highly efficient cellulose and lignin-decomposing bacteria, with a total effective viable bacteria count ≥100 million / g, and its main functional bacteria include, but are not limited to, at least two of Bacillus subtilis, Aspergillus niger, Aspergillus oryzae, and Trichoderma.
[0011] Step 3: Using a three-year cycle, an intermittent deep plowing and "one deep, two rotary" tillage system is adopted. Activated carbon source and stable carbon source are applied to the soil according to a preset carbon ratio and application plan within the tillage cycle to achieve rapid improvement of soil organic matter and continuous improvement of the topsoil structure. Specifically, in the first wheat season, a 25-30 cm deep plowing is carried out, accompanied by a one-time application of a three-year supply of stable carbon source. In the following two consecutive wheat seasons, rotary tillage at a depth of 15-18 cm is carried out, accompanied by an equal amount of activated carbon source applied each year. The total annual carbon application is ≥140 kg / mu, and the carbon ratio of stable carbon source to activated carbon source is 7:3.
[0012] Preferably, the stable carbon source is at least one of biochar and peat products, and the active carbon source is at least one of humic acid and bio-organic fertilizer; wherein, the bio-organic fertilizer refers to a product that meets the agricultural industry standard NY 884-2012 "Bio-organic Fertilizer", and its organic matter content (on a dry basis) is ≥40%, and its effective viable bacteria count is ≥0.20 billion / gram.
[0013] Preferably, apply an additional 2-3 kg N per mu when sowing wheat in the first year.
[0014] The present invention has the following advantages:
[0015] (1) Systematic: The three major management links of water, salt and fertilizer are designed and implemented as a whole, breaking the fragmented mode of "treating the head when it hurts and the foot when it hurts" in traditional technology.
[0016] (2) Resource efficiency: By “storing rainwater and using saline water”, the time and space allocation and efficient utilization of unconventional water resources have been realized, breaking the “water source bottleneck” in the improvement of water-scarce saline-alkali areas.
[0017] (3) Rapid and long-lasting effect: Through the three-dimensional salt control mode of "engineering measures to remove salt, straw layer to block salt, and straw mulch to suppress salt", and the fertilization mode of "combination of biological activity and stable carbon source" and "intermittent deep plowing", it can not only rapidly reduce the salt content in the root zone and increase organic matter, but also form a long-lasting salt barrier layer and a stable soil carbon pool, with lasting effect.
[0018] (4) Economic feasibility: It makes full use of local straw resources and brackish water, reduces dependence on external fresh water and high-cost engineering measures, and the technical model is low-cost, easy to promote, and has good application prospects. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0020] Figure 1 This is a comparison chart of the salinity of topsoil.
[0021] Figure 2 This is a comparison chart of the bulk density of topsoil.
[0022] Figure 3 This is a comparison chart of the organic matter content in the topsoil.
[0023] Figure 4 A comparison chart showing the content of easily oxidized organic carbon in the topsoil.
[0024] Figure 5 A comparison chart of topsoil quality grades for arable land.
[0025] Figure 6 This is a comparison chart of crop yields. Detailed Implementation
[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0027] Example 1
[0028] Step 1: Dig a water storage ditch between two adjacent strip fields. The ditch should be 2 m wide at the bottom, 4 m wide at the top, and 2 m deep. Lay a waterproof plastic film inside the ditch to collect summer rainwater for irrigation of spring and autumn crops.
[0029] Step two: Dig open ditches between the strips of land, with a spacing of 50 m, a depth of 1.5 m, a bottom width of 1 m, and a top width of 3 m.
[0030] Returning straw to the field:
[0031] Corn stalks: Crush to 3 cm at harvest and spray with 2 kg / mu of composting agent (composed of Bacillus subtilis, Aspergillus niger, and Trichoderma, with a total effective viable count ≥200 million / g). Every three years before wheat sowing, use a three-furrow plow to deeply plow to a soil layer of 28 cm to form a straw layer; in other years, rotary till 16 cm of soil to mix the straw into the soil layer.
[0032] Wheat straw: Crush it to 3 cm at harvest, cover it evenly on the ground, and spray it with 2 kg / mu of composting agent, and then sow corn without tillage.
[0033] Step 3: Select woody peat as a stable carbon source and bio-organic fertilizer (organic matter content ≥40%, effective live bacteria count ≥0.20 billion / gram) as an active carbon source, and mix the two at a carbon ratio of 7:3, with a total annual carbon application of 140 kg / mu. In the first wheat season, apply the woody peat (total amount for three years) all at once during deep plowing; in the following two years, apply the bio-organic fertilizer (annual application amount) in equal amounts during wheat sowing each year, combined with rotary tillage.
[0034] Step four: Perform fertilization and sowing operations according to conventional methods. The fertilizer types are nitrogen, phosphorus, and potassium single-element fertilizers. The nitrogen fertilizer is urea, the phosphorus fertilizer is superphosphate, and the potassium fertilizer is potassium sulfate. During the wheat sowing season, the nitrogen, phosphorus, and potassium fertilizer application rates are 16 kg N / mu and 18 kg P2O5 / mu, respectively. No potassium fertilizer is applied. When fertilizing, the nitrogen and phosphorus nutrients brought in by the bio-organic fertilizer should be deducted. During the corn sowing season, the nitrogen, phosphorus, and potassium fertilizer application rates are 12 kg N / mu, 4 kg P2O5 / mu, and 4 kg K2O / mu, respectively. At the same time, an additional 2 kg N / mu of chemical nitrogen fertilizer is applied when sowing wheat in the first year.
[0035] During the jointing stage of winter wheat in spring, supplemental irrigation should be carried out once with slightly saline water with a mineralization degree ≤3 g / L. After summer maize is sown, freshwater irrigation should be carried out using rainwater from water storage ditches.
[0036] Example 2
[0037] The differences from Example 1 are as follows: 1) Open ditches are dug between the strips of land, with a spacing of 55 m, a depth of 2 m, a bottom width of 1.5 m, and a top width of 3.5 m. 2) Corn stalks are shredded to 4 cm at harvest and sprayed with 2.5 kg / mu of composting agent; wheat stalks are shredded to 4 cm at harvest and sprayed with 2.5 kg / mu of straw composting agent. 3) The total annual carbon application is 160 kg / mu. 4) An additional 3 kgN / mu of chemical nitrogen fertilizer is applied.
[0038] Example 3
[0039] The differences from Example 1 are as follows: 1) Open ditches are dug between the strips of land, with a spacing of 60 m, a depth of 2.5 m, a bottom width of 2 m, and a top width of 4 m. 2) Corn stalks are shredded to 5 cm at harvest and sprayed with 3 kg / mu of composting agent; wheat stalks are shredded to 5 cm at harvest and sprayed with 3 kg / mu of composting agent. 3) Biochar is applied. 4) An additional 3 kg N / mu of chemical nitrogen fertilizer is applied.
[0040] Experimental Example 1
[0041] From 2022 to 2025, an integrated salt control, carbon enrichment, and fertilization study was conducted on moderately saline-alkali farmland in Haixing County, Cangzhou City, Hebei Province, in a coastal water-scarce saline-alkali area. This region has a warm temperate continental monsoon climate with an average annual rainfall of 582 mm, mainly concentrated in August and September. The experimental soil was coastal saline soil, with an initial salt content of 2.50 g / kg in the 0-20 cm topsoil layer, organic matter of 12.23 g / kg, readily oxidizable organic carbon of 1.55 g / kg, total nitrogen of 0.69 g / kg, available nitrogen of 48.38 mg / kg, available phosphorus of 12.37 mg / kg, available potassium of 87.03 mg / kg, and a pH of 8.44. A winter wheat-summer maize rotation system was adopted, with four treatment groups: a conventional planting pattern (control) and examples 1-3. The results are shown in the table below. Figure 1-6 .
[0042] Depend on Figure 1-6It is evident that, compared to conventional planting methods, after three consecutive years of implementation using the integrated method described in this invention, the soil physicochemical properties, fertility levels, and crop yield in the experimental area were significantly and synergistically improved. Specifically, the effects were as follows: Salt control and bulk density reduction were significant, with the salt content in the 0-20 cm topsoil layer decreasing by 12.2-22.2% and the soil bulk density decreasing by 5.2-6.9% in the application area, effectively alleviating salt stress and improving soil physical structure. Carbon enrichment and fertilization were outstanding, with soil organic matter content increasing by 16.3-25.5%; most importantly, soil carbon activity and quality, characterized by easily oxidizable organic carbon, were significantly improved, with an increase of 23.8-42.8%. Soil quality and yield were synergistically improved; based on the above-mentioned improvement effects, the soil quality grade in the experimental area improved by 0.54-0.76 units. Correspondingly, crop yields increased significantly, with winter wheat yields increasing by an average of 17.2-20.7% and summer maize yields increasing by an average of 10.2-17.4%, resulting in a 13.0-17.5% increase in total annual crop production capacity. This invention successfully achieved the integrated and synergistic advancement of the three major goals of "salt control," "carbon increase," and "fertility improvement" in coastal water-scarce saline-alkali areas, providing an effective technical approach for the rapid restoration of fertility and efficient improvement of production capacity in such low- and medium-yield fields.
[0043] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A coastal water-deficient saline-alkali region soil salt control and carbon increase and fertilization integrated method, characterized in that, It comprises the following steps: Step one: digging water storage ditch between adjacent fields, laying waterproof membrane inside the water storage ditch, collecting summer rainfall, irrigating in spring and autumn during crop sowing and key growth period, and using surface brackish water for supplementary irrigation; Step two: laying a buried pipe in the field with the condition of laying a buried pipe, and digging a open ditch with a spacing of 50-60 m in the field without the condition of laying a buried pipe, differentiating crop straw and spraying 2-3 kg / mu of decomposed agent; Step three: deep plowing 25-30 cm in the first year of wheat season, and one-time application of stable carbon source for three years, followed by rotary tillage with a depth of 15-18 cm for two consecutive years, and equal amount of active carbon source is applied every year, the total carbon application amount is ≥140 kg / mu every year, and the carbon amount ratio of stable carbon source to active carbon source is 7:
3.
2. The method according to claim 1, characterized in that, The water storage ditch in step one has a bottom width of 2 m, an upper opening width of 4 m, and a depth of 2 m.
3. The method according to claim 1, characterized in that, The supplementary irrigation operation in step one is to supplement once with brackish water with a mineralization degree of ≤3 g / L during the spring jointing period of winter wheat, and 1-2 times with brackish water with a mineralization degree of ≤2 g / L during the middle and late growth period of summer corn.
4. The method according to claim 1, characterized in that, The open ditch in step two has a depth of 1.5-2.5 m, a bottom width of 1-2 m, and an upper opening width of 3-4 m.
5. The method according to claim 1, wherein, The crop straw differentiating method in step two is to crush corn straw in situ to 3-5 cm, and turn it into 25-30 cm soil layer 7-15 days before wheat sowing, which is implemented every 2-3 years; wheat straw is crushed in situ to 3-5 cm, evenly covered on the ground, and then immediately sowed with corn without tillage.
6. characterized in that, The decomposed agent in step two is one or more of bacillus subtilis, aspergillus niger, aspergillus oryzae and trichoderma, and the total number of effective live bacteria is ≥100 million / g.
7. The method according to claim 1, characterized in that, The stable carbon source in step three is at least one of biomass charcoal and peat products.
8. The method according to claim 1, characterized in that, The active carbon source in step three is at least one of fulvic acid and bio-organic fertilizer.
9. The method according to claim 8, wherein, The bio-organic fertilizer has an organic matter content of ≥40% and an effective live bacteria number of ≥0.20 billion / g.
10. The method according to claim 1, characterized in that, It also includes increasing 2-3 kg N per mu during wheat sowing in the first year.