Method for improving moderate and severe saline-alkali soil based on layered salt control and crop synergistic interaction

Abstract

The invention provides a moderately severe saline-alkali soil improvement method based on layered salt control and crop synergistic interaction, and belongs to the technical field of saline-alkali soil treatment and improvement. The method comprises the following steps that ridging is conducted on the ground, the ridge height ranges from 7 cm to 13 cm, the ridge face width ranges from 22 cm to 28 cm, and the furrow width ranges from 8 cm to 12 cm; planting saline-alkaline tolerant crops on ridge surfaces, and planting economic or grain crops on furrows; in the crop harvesting period, the overground part of the saline-alkaline tolerant crop is removed. Through micro-topography reconstruction and salt-tolerant crop configuration, rapid improvement of the moderate and severe saline-alkali soil is realized, the seed germination rate and the seedling survival rate are effectively improved, and the economic value of the saline-alkali soil is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of saline-alkali land management and improvement, and specifically relates to a method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy. Background Art

[0002] Saline-alkali land refers to a type of soil that contains large amounts of soluble salts or alkaline substances, resulting in excessive salinization or alkalinization, seriously impacting crop growth and the ecological environment. The soil structure in saline-alkali land deteriorates, with poor aeration and water permeability. The soil becomes hard and compacted, and its temperature rises slowly. Salts are mixed into the compacted soil and are difficult to separate, resulting in annual precipitation and increasing salt content. Furthermore, essential mineral elements for crops precipitate due to the high soil pH, making them difficult for crops to absorb and utilize. This leads to low land utilization and reduced crop yield and quality. Furthermore, saline-alkali land is prone to environmental problems such as land degradation and desertification, threatening the stability of the ecosystem. Therefore, the management of saline-alkali land has important ecological, economic, and social significance.

[0003] As global soil salinization worsens, fully tapping the potential for saline-alkali land development and utilization, and improving moderately and severely saline-alkali land, has become a major challenge for sustainable agricultural development. Currently, numerous methods are available for improving saline-alkali land, primarily including engineering, biological, and chemical amendments. Engineering, such as building integrated irrigation and drainage systems, reduces soil salinity through integrated irrigation and drainage measures, offering rapid improvement results but at a high cost. Biological amendments, through agronomic measures such as increasing the application of organic fertilizers, returning straw to the fields for fertilization, planting green manure, and cultivating salt-tolerant crops, improve soil physical and chemical properties with good results, but with a longer improvement cycle. Chemical amendments, by adding calcium and acidic substances to alkaline soils, reduce soil salinity quickly, but are prone to recurring problems. Another approach, such as saline-alkali land remediation systems, involves stratified drainage of salt through underground tiered drainage pipes, real-time monitoring systems, control centers, and auxiliary irrigation systems. While these systems can improve improvement efficiency and optimize water resource utilization, they are complex and costly.

[0004] Existing land reclamation technologies have significant limitations in practical application, making it difficult to balance economic viability, ecological safety, and efficiency. For moderately and severely saline-alkali lands, the high salt content and poor physical and chemical properties of the soil are particularly problematic, and existing land reclamation methods often fail to achieve the desired results. Therefore, a comprehensive land reclamation approach integrating stratified salt control, biological regulation, and engineering intervention is urgently needed. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the first purpose of the present invention is to provide a method for improving moderate to severe saline-alkali land based on layered salt control and crop synergy, which can significantly reduce the salinity and alkali content of the soil and improve the economic value of saline-alkali land.

[0006] The second object of the present invention is to provide the application of the above-mentioned method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy in agricultural planting.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for improving moderate to severe saline-alkali land based on layered salt control and crop synergy, comprising the following steps: forming ridges on the ground with a ridge height of 7 to 13 cm, a ridge surface width of 22 to 28 cm, and a ridge ditch width of 8 to 12 cm; planting salt-alkali-tolerant crops on the ridge surface and economic or food crops in the ridge ditch; and removing the above-ground parts of the salt-alkali-tolerant crops during the crop harvest period.

[0009] Preferably, the salt content of the moderately to severely saline-alkali land is 0.5% to 1.2%.

[0010] Preferably, a drip irrigation tape is laid on the ridge surface.

[0011] Preferably, the salt-alkali tolerant crops include Jerusalem artichoke, sesbania, sorghum and ryegrass.

[0012] Preferably, the economic or food crops include cotton and corn.

[0013] Preferably, fertilization and deep plowing are carried out before ridging; the fertilization is the application of decomposed cow dung and saline-alkali land improver.

[0014] Preferably, the deep plowing is 40 cm deep plowing.

[0015] Preferably, the saline-alkali land improving agent includes phosphogypsum.

[0016] Preferably, farming is completed using an integrated machine that performs fertilization, ridging, laying drip irrigation tapes, sowing, and mulching.

[0017] The present invention also provides the application of the above-mentioned method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy in agricultural planting.

[0018] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0019] The method for improving moderately and severely saline-alkali land provided by this invention overcomes current technical bottlenecks: first, a single improvement method cannot simultaneously address the stratified distribution of salt, which accumulates in the upper reaches and stores in the lower reaches; second, there is a lack of a mechanism to synergize salt migration control with the physiological characteristics of crop salt tolerance; and third, the contradiction between high costs, long cycles, and low effectiveness has hindered the dissemination of this technology. This invention, based on a stratified salt control technology system based on the vertical differentiation of salt content and combining it with the coordinated planting of salt-tolerant crops and halophytes, overcomes the passive control of salt migration by traditional technologies, shortens the improvement cycle, reduces overall costs, effectively improves seed germination and seedling survival rates, and enhances the economic value of saline-alkali land. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : Schematic diagram of ridge formation. DETAILED DESCRIPTION

[0021] The present invention provides a method for improving moderate to severe saline-alkali land based on layered salt control and crop synergy, comprising the following steps: forming ridges on the ground with a ridge height of 7 to 13 cm, a ridge surface width of 22 to 28 cm, and a ridge ditch width of 8 to 12 cm; planting salt-alkali-tolerant crops on the ridge surface and economic or food crops in the ridge ditch; and removing the above-ground parts of the salt-alkali-tolerant crops during the crop harvest period.

[0022] The ridge height of the present invention is preferably 8 cm, 9 cm, 10 cm, 11 cm, or 12 cm; the ridge width is preferably 23 cm, 24 cm, 25 cm, 26 cm, or 27 cm; and the furrow width is preferably 9 cm, 10 cm, or 11 cm. The ridge of the present invention is preferably trapezoidal. The ridge surface is preferably paved with drip irrigation tape.

[0023] The moderately to severely saline-alkali land described in the present invention is preferably the moderately to severely saline-alkali land in the Yellow River Delta in Dongying, Shandong Province. The salt content of the moderately to severely saline-alkali land is 0.5% to 1.2%, preferably 0.8% to 1.1%.

[0024] The salt-alkali tolerant crops of the present invention include Jerusalem artichoke, sesbania, sorghum and ryegrass; the economic or food crops include cotton and corn. As an optional embodiment, the present invention plants Jerusalem artichoke on the ridge surface and plants cotton in the furrow; as another optional embodiment, the present invention plants sesbania on the ridge surface and plants corn in the furrow. The salt-alkali tolerant crops of the present invention can be turned over to fertilize the soil, can grow normally and absorb the corresponding amount of salt from the soil, and can be removed from the target soil through the aboveground part, thereby reducing the salt content in the heavily saline-alkali land. The economic or food crops of the present invention can germinate and grow normally, thereby increasing the economic value of the saline-alkali land.

[0025] The present invention causes uneven evaporation of the ground surface by setting up high and low ridges as micro-topography, so that water and salt in low places move to high places, thereby inducing salt surface accumulation. The topsoil layer with high salt content can be concentrated on the back of the ridge (high ridge), and seeds are sown in the furrows with low salt content (ridge furrows), which is beneficial to seed germination and seedling formation, and the seed germination rate and seedling survival rate can be greatly improved.

[0026] Before ridging, the present invention preferably performs fertilization and deep plowing; the fertilization comprises the application of decomposed cow manure and a saline-alkali soil conditioner; the deep plowing is performed at a depth of 40 cm. Deep plowing breaks up the compacted layer, and the application of the saline-alkali soil conditioner further reduces the damage to crops caused by saline-alkali soil. As an optional embodiment, the saline-alkali soil conditioner comprises phosphogypsum, and the fertilization rate is 3.5 tons / mu of decomposed cow manure plus 220 kg / mu of phosphogypsum.

[0027] The present invention preferably utilizes a mechanical-agronomic integration system, employing a single machine for fertilization, ridging, drip irrigation, seeding, and mulching. This system achieves a 300-fold increase in efficiency compared to traditional segmented operations, with a precision application error rate of <±5% (compared to the >30% error rate for traditional manual application). This system achieves rapid improvement through the integration of micro-topography reconstruction, salt-tolerant crop deployment, and mechanical integration.

[0028] The present invention also provides the application of the above-mentioned method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy in agricultural planting.

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] In the following examples, unless otherwise specified, all methods are conventional.

[0031] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0032] Example 1

[0033] From 2022 to 2024, the experiment was carried out in the moderate and severe saline-alkali land in the Yellow River Delta in Dongying, Shandong. Before the start of the experiment, soil samples at 0-20 cm were taken for analysis and testing using a conductivity meter. The original soil salt content was 1.2%.

[0034] Apply 3.5 tons / mu of decomposed cow dung + 220kg / mu of phosphogypsum every year; deep plow 40cm to break up the compacted layer, make ridges, ridge height 10±3cm, ridge width 25±3cm, ridge ditch width 10±2cm, lay drip irrigation belts on the ridge surface, and carry out integrated water and fertilizer drip irrigation according to the key growth period of the crop, seedling stage, jointing stage, and filling stage. Figure 1 shown.

[0035] In 2022 and 2023, Jerusalem artichokes will be planted on the back of the ridges (high ridges) with a row spacing of 35 cm and a plant spacing of 30 cm; cotton will be planted in the furrows with a row spacing of 35 cm and a plant spacing of 15 cm; in mid-October each year, the above-ground part of the Jerusalem artichokes will be removed from the target soil.

[0036] In 2024, sesbania will be planted on the back of the ridge (high ridge), with the sowing method being row sowing and the planting density (seeding amount) being 3 to 4 kg per mu; corn will be planted in the furrows with a row spacing of 35 cm and a plant spacing of 30 cm; in mid-October, the above-ground part of the sesbania will be removed from the target soil.

[0037] After the harvest of cash crops from 2022 to 2024, soil samples at 0-20 cm on the ridge back and ridge furrow were taken using a conductivity meter for analysis and testing to obtain the soil salinity. The biomass of Jerusalem artichoke, sesbania, cotton, and corn were also tested. The results are shown in Tables 1 and 2.

[0038] Table 1 Salinity changes in the microtopography-salinity coordinated regulation system in different years

[0039] year Salt content on ridge back (%) Salt content in ridges and furrows (%) Salt content reduction rate % 2022 0.98 0.53 45.92 2023 0.74 0.44 40.54 2024 0.59 0.31 47.46

[0040] Note: Salt content reduction rate (%) = (salt content on ridge surface - salt content on ridge ditch) / salt content on ridge surface × 100%.

[0041] Table 2 Statistics of annual salt uptake and biomass of different crops

[0042] crop Salt tolerance threshold Annual salt absorption (kg / mu) Biomass (tons / mu) Jerusalem artichoke 0.8％ 4.7 2.3 Sesbania tian 0.7％ 3.2 1.8 cotton 0.3％ 0.9 0.3 (straw) corn 0.2％ 0.8 0.2 (straw)

[0043] The results showed that the salinity in the ridge ditch was reduced by 40.54% to 47.46% compared with the salinity on the ridge surface. The annual salt absorption of Jerusalem artichoke and sesbania was significantly higher than that of cotton and corn, which could effectively reduce the salt-alkali damage to cotton and corn.

[0044] Example 2

[0045] This example was conducted in a severely saline-alkali land in Dongying City, Shandong Province. Before the experiment began, soil samples at 0 to 20 cm were taken for analysis using a conductivity meter. The original soil salt content was 0.82%.

[0046] Apply 3.5 tons / mu of decomposed cow dung + 220kg / mu of phosphogypsum every year; deep plowing 40cm to break up the compacted layer, make ridges with a ridge height of 10±3cm, a ridge width of 25±3cm, and a ridge ditch width of 10±2cm. Lay drip irrigation tapes on the ridge surface, and carry out integrated water and fertilizer drip irrigation according to the key growth period of the crop, namely the seedling stage, jointing stage, and filling stage.

[0047] In 2022 and 2023, Jerusalem artichokes will be planted on the back of the ridges (high ridges) with a row spacing of 35 cm and a plant spacing of 30 cm; cotton will be planted in the furrows with a row spacing of 35 cm and a plant spacing of 15 cm; in mid-October each year, the above-ground part of the Jerusalem artichokes will be removed from the target soil.

[0048] In 2024, sesbania will be planted on the back of the ridge (high ridge), with row sowing and a planting density (seeding amount) of 3 to 4 kg per mu; cotton will be planted in the ridge furrows with a row spacing of 35 cm and a plant spacing of 15 cm; in mid-October, the sesbania will be turned over and returned to the field to improve soil fertility.

[0049] Mechanical operation: the ridge back is equipped with a machine that can be used for ridge forming, fertilizing, sowing and mulching, while the furrows are sown separately.

[0050] Table 3 Mechanical operation parameters

[0051] Job parameters Numerical Ridge height and depth 10.2cm±0.3cm Modifier application amount (phosphogypsum) <![CDATA[220kg / 667m 2 ]]> Film thickness 0.008mm biodegradable film

[0052] The crop growth data from 2022 to 2024 were collected, and the results are shown in Table 4.

[0053] Table 4 Crop growth data

[0054] year Jerusalem artichoke salt absorption Sesbania truncatula cotton production 2022 4.2kg / mu - 85kg / mu 2023 4.8kg / mu - 132kg / mu 2024 - 2.3 tons / mu 198kg / mu

[0055] The results showed that after three years of continuous planting, the yield of various crops increased significantly.

[0056] The changes in soil indicators from 2022 to 2024 were statistically analyzed and tested by taking soil samples from 0 to 20 cm on the ridge back and ridge furrow using a conductivity meter to obtain the salt content of the plow layer. The results are shown in Table 5.

[0057] Table 5 Changes in soil indicators

[0058]

[0059] The results showed that after three consecutive years of planting, the salt content of ridge backs and furrows decreased from 0.68% and 0.42% to 0.43% and 0.22% respectively, with a decrease of 36.8% to 47.6%. The soil pH, sodium adsorption ratio SAR and exchangeable sodium ratio ESP decreased simultaneously, and the land was changed from severely saline-alkali land to moderately saline-alkali land.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy, characterized in that: The method comprises the following steps: forming ridges on the ground with a ridge height of 7 to 13 cm, a ridge surface width of 22 to 28 cm, and a ridge furrow width of 8 to 12 cm; planting salt-alkali tolerant crops on the ridge surface and planting economic or food crops in the furrow; and removing the above-ground parts of the salt-alkali tolerant crops during the crop harvest period.

2. The method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to claim 1, characterized in that: The salt content of the moderately to severely saline-alkali land is 0.5% to 1.2%.

3. The method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to claim 1, characterized in that: A drip irrigation tape is laid on the ridge surface.

4. The method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to claim 1, characterized in that: The salt-alkali tolerant crops include Jerusalem artichoke, sesbania, sorghum and ryegrass.

5. The method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to claim 1, characterized in that: The cash or food crops include cotton and corn.

6. The method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to claim 1, characterized in that: Fertilization and deep plowing are carried out before ridging; the fertilization is the application of decomposed cow dung and saline-alkali land improver.

7. The method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to claim 6, characterized in that: The deep plowing is 40 cm deep plowing.

8. The method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to claim 6, characterized in that: The saline-alkali land improving agent includes phosphogypsum.

9. The method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to claim 6, characterized in that: Farming is completed using an integrated machine that applies fertilizers, forms ridges, lays drip irrigation tapes, sows seeds, and covers the land.

10. Application of the method for improving moderate to severe saline-alkali land based on stratified salt control and crop synergy according to any one of claims 1 to 9 in agricultural planting.

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