Saline-alkali soil improvement method

Abstract

The invention belongs to the technical field of soil remediation, and particularly relates to a saline-alkali soil improvement method which comprises the following steps: soil preparation: irrigating after ploughing; compacting the soil: compacting the air-dried soil; planting of the gramineae plants and the leguminous plants: intercropping the gramineae plants and the leguminous plants after rotary tillage, wherein the distance between the adjacent gramineae plants and leguminous plants is 30-45cm. According to the method, a blocking layer for limiting downward movement of soil moisture and upward migration of underground moisture is formed in a soil compaction mode, salt moves along with repeated evaporation of moisture is established, before compaction, soil is turned over and irrigated, salt is promoted to permeate downwards, compaction is conducted after turning over and irrigating, on one hand, salt infiltration is further promoted, on the other hand, the salt content is reduced, and the soil quality is improved. After compaction, surface soil is subjected to rotary tillage to loosen, so that root systems of the corn and the soybeans laterally develop, and the surface soil is improved by utilizing ecological habits of different crops and a root system distribution difference principle.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil remediation, and particularly relates to a method for improving saline-alkali soil. Background Art

[0002] The formation of alkali soil and alkalized soil in China is mostly related to the accumulation of carbonates in the soil. mainly due to small precipitation and large evaporation, the salts dissolved in water are likely to accumulate on the soil surface layer, so the alkalization degree is generally high, and plants can hardly survive in severely saline-alkali soil areas.

[0003] Therefore, the current urgent problem to be solved is to study the treatment plan and action mechanism for saline-alkali soil in the northwest region, condition the physical and chemical properties of the soil, increase crop yields, and reduce the improvement cost. At present, the commonly used methods for improving saline-alkali soil include water conservancy improvement method, physical improvement method, chemical improvement method and biological improvement method. The water conservancy improvement method is based on the "water-salt movement" law, and discharges salts through underground infiltration pipes, combined with ditches and deep wells for drainage to prevent salt return. The project volume is relatively large; the physical improvement method is to level the land, replace the soil, press sand, loosen the soil, raise the field, etc., to destroy the capillary action of the soil and block the further accumulation of salts on the ground surface. The soil replacement method has a large project volume and high cost, and the economic cost is uneconomical; the chemical improvement method is to add chemical substances to the soil to reduce the soil pH, alkalization degree and improve the soil structure. On severely saline-alkali land, the main chemical improvers include gypsum, phosphogypsum, desulfurized gypsum, sulfur, humic acid, furfural residue and other substances, which can achieve extremely significant improvement effects, but the introduction of chemical substances may further damage the microbial community structure of the soil; the biological improvement method mainly includes improving the soil with microbial bacterial fertilizer or planting salt-tolerant plants, which is beneficial to the restoration of the soil environment and has been widely used. However, most of the microbial bacterial fertilizer improvers currently used are composed of exogenous microorganisms, which compete with the indigenous soil microorganisms, resulting in the invasion of exogenous microbial species or being inhibited by indigenous microorganisms, and their treatment effects are limited. Among the current methods for improving saline-alkali soil, although the physical improvement method can block the accumulation of salts on the ground surface, there is a problem of salt rebound over time. Summary of the Invention

[0004] To solve the above problems, the present invention provides a method for improving saline-alkali soil.

[0005] A method for improving saline-alkali soil includes the following steps:

[0006] Land preparation: Irrigate after plowing.

[0007] Soil compaction: Compact the soil after air drying.

[0008] Planting of gramineous plants and leguminous plants: Intercropping of gramineous plants and leguminous plants after rotary tillage, and the distance between adjacent gramineous plants and leguminous plants is 30 cm to 45 cm.

[0009] Preferably, when planting the gramineous plants and leguminous plants, a planting method of two to three rows of gramineous plants and two rows of leguminous plants is adopted.

[0010] Preferably, the row spacing of the gramineous plants is 30 cm to 40 cm, and the row spacing of the leguminous plants is 30 cm to 40 cm.

[0011] Preferably, after compaction, the bulk density of the soil is 1.5 g / cm 3 ~1.7 g / cm 3 .

[0012] Preferably, the thickness of the irrigation water layer for irrigation is 5 cm to 8 cm.

[0013] Preferably, fertilization is carried out after planting the gramineous plants and leguminous plants.

[0014] Preferably, the fertilization is the application of farmyard manure.

[0015] Preferably, the pH in the saline-alkali land is 7.5 to 9.5, and the soil salt content is 0.4% to 0.55%.

[0016] Preferably, the gramineous plant is corn.

[0017] Preferably, the leguminous plant is soybean.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] Before compaction, the present invention plows and irrigates the soil to promote the downward penetration of salts. After plowing and irrigation, compaction is carried out. On the one hand, it further promotes the downward infiltration of salts, reduces the soil porosity and increases the soil firmness in the way of soil compaction, forming a "barrier layer" that restricts the downward movement of soil water and gas and the upward migration of underground water. On the other hand, after compaction, the surface soil is loosened by rotary tillage, creating a "loose upper and firm lower" growth environment for crop roots, enabling the lateral development of the roots of corn and soybean. Using the principle of the ecological habits and root distribution differences of different crops, the soil is improved by the growth of roots after the formation of the barrier layer, making the compaction layer hinder the water and salt migration, avoiding the salt rebound, and improving the surface soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the method principle of the present invention.

[0021] Figure 2 is a schematic diagram of the method principle of Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the protection scope of the present invention is not limited by the specific embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0023] 1. Principle of improving land by soil compaction technology

[0024] The present invention changes the physical and chemical properties of the soil by soil compaction. Tractors and other mechanical rollers are used to repeatedly roll the cultivated land to reduce the soil porosity and increase the soil firmness (the soil bulk density after compaction increases by 5% of the original bulk density). A rotary tiller is used to loosen the surface soil, thereby creating a crop root growth environment of "loose top and firm bottom". In this way, the soil bulk density and the proportion of small pores are increased to limit the downward movement of soil water and gas and the upward migration of underground water, establish a "barrier layer" for the repeated evaporation movement of salt with water, and at the same time inhibit the downward growth of crop roots and promote the lateral development of roots, which is beneficial to ensuring root water absorption during the drought period.

[0025] 2. Principle of improving quality and increasing yield by the intercropping pattern of cereal and legume

[0026] The intercropping of cereal and legume belongs to an efficient agricultural production method. Compared with leguminous plants, the roots of gramineous plants are generally deeper and the growth period is longer. It can improve the photosynthetically active radiation, nutrient and water use efficiency. The interaction of roots significantly increases the soil organic carbon concentration and alkaline phosphatase activity. It also affects the bacterial diversity in the soil by improving the soil nitrogen and water use efficiency and promoting the reproduction of rhizosphere soil microorganisms. Using the principle of the ecological habits and root distribution differences of different crops can not only give full play to the potential of cultivated land, improve the soil quality of saline-alkali land, save the input cost of fertilizers, but also make the soil quality tend to be healthy, and promote the development of agriculture and the improvement of the ecological environment.

[0027] The roots of corn are very developed, with a large number of slender lateral root branches and root hairs, while the root branches of soybeans are very few and the root hairs are also few. However, after intercropping soybeans with corn, the distribution pattern of soybean roots changes. The roots of single-cropped soybeans grow vertically downward, while the shape of the roots of intercropped soybeans depends on the shape of corn.

[0028] Example 1

[0029] A method for improving saline-alkali land, comprising the following steps:

[0030] Land preparation: Plow the saline-alkali land to loosen the soil. After plowing, irrigate the land. The thickness of the water layer for irrigation is 8 cm. Loosen the soil before irrigation to make it easier for salt to penetrate downward.

[0031] Soil compaction: After irrigation and air-drying, the soil is compacted. When compacting, a tractor with a mechanical roller is used to roll the cultivated land multiple times to reduce the soil porosity and increase the soil firmness. In this way, the soil bulk density and the proportion of small pores are increased to limit the downward movement of soil water and gas and the upward migration of groundwater, establish a "barrier layer" for the repeated evaporation movement of salt with water, and at the same time inhibit the downward growth of crop roots and promote the lateral development of roots, which is beneficial to ensuring root water absorption during the drought period. After compaction, the soil bulk density is 1.5 g / cm 3 .

[0032] Planting of gramineous plants and leguminous plants: After compaction, rotary tillage is carried out with a rotary tiller, and the rotary tillage depth is 15 cm. After rotary tillage, sowing is carried out in the way of two rows of corn and two rows of soybeans. The row spacing between the two rows of corn is 30 cm, the hole spacing is 30 cm, the hole depth is 2 cm, and 3 corn seeds are sown in each hole; for two rows of soybeans: the row spacing is 30 cm, the hole spacing is 20 cm, the hole depth is 2 cm, and 2 soybean seeds are sown in each hole.

[0033] Example 2

[0034] A method for improving saline-alkali land, comprising the following steps:

[0035] Land preparation: Plowing is carried out on the saline-alkali land to loosen the soil. After plowing, irrigation is carried out, and the water layer thickness of irrigation is 5 cm. Plowing before irrigation loosens the soil, making it easier for salt to penetrate downward.

[0036] Soil compaction: After irrigation and air-drying, the soil is compacted. When compacting, a tractor with a mechanical roller is used to roll the cultivated land multiple times to reduce the soil porosity and increase the soil firmness. In this way, the soil bulk density and the proportion of small pores are increased to limit the downward movement of soil water and gas and the upward migration of groundwater, establish a "barrier layer" for the repeated evaporation movement of salt with water, and at the same time inhibit the downward growth of crop roots and promote the lateral development of roots, which is beneficial to ensuring root water absorption during the drought period. After compaction, the soil bulk density is 1.6 g / cm 3 .

[0037] Planting of gramineous plants and leguminous plants: After compaction, rotary tillage is carried out with a rotary tiller, and the rotary tillage depth is 20 cm. After rotary tillage, sowing is carried out in the way of two rows of corn and two rows of soybeans. The row spacing between the two rows of corn is 40 cm, the hole spacing is 30 cm, the hole depth is 2.5 cm, and 4 corn seeds are sown in each hole; for two rows of soybeans: the row spacing is 40 cm, the hole spacing is 20 cm, the hole depth is 2 cm, and 2 soybean seeds are sown in each hole.

[0038] Example 3

[0039] A method for improving saline-alkali land, comprising the following steps:

[0040] Land preparation: Plow the saline-alkali land to loosen the soil. After plowing, irrigate the land. The water layer thickness during irrigation is 5 cm to 8 cm. Plow the soil before irrigation to make it loose, so that salts can more easily penetrate downward.

[0041] Soil compaction: After the water has dried, compact the soil. When compacting, use a tractor with a mechanical roller to roll the cultivated land multiple times to reduce the soil porosity and increase the soil firmness. In this way, increase the soil bulk density and the proportion of small pores to limit the downward movement of soil water and gas and the upward migration of groundwater after compaction, establish a "barrier layer" for the repeated evaporation movement of salts with water, and at the same time inhibit the downward growth of crop roots and promote the lateral development of roots, which is beneficial to ensuring root water absorption during the dry period. After compaction, the bulk density of the soil is 1.7 g / cm 3 。

[0042] Planting of gramineous plants and leguminous plants: After compaction, use a rotary tiller to till the soil. The tillage depth is 20 cm. After tillage, sow in the pattern of two rows of corn and two rows of soybeans. The row spacing between the two rows of corn is 40 cm, the hole spacing is 30 cm, and the hole depth is 2 cm. Sow 4 corn seeds in each hole; for the two rows of soybeans: with a row spacing of 40 cm, a hole spacing of 20 cm, a hole depth of 2 cm, and sow 3 soybean seeds in each hole.

[0043] Comparative Example 1

[0044] The difference between Comparative Example 1 and Example 1 is that no land preparation is carried out. Specifically:

[0045] A method for improving saline-alkali land includes the following steps:

[0046] Soil compaction: After the water has dried, compact the soil. When compacting, use a tractor with a mechanical roller to roll the cultivated land multiple times to reduce the soil porosity and increase the soil firmness. In this way, increase the soil bulk density and the proportion of small pores to limit the downward movement of soil water and gas and the upward migration of groundwater after compaction, establish a "barrier layer" for the repeated evaporation movement of salts with water, and at the same time inhibit the downward growth of crop roots and promote the lateral development of roots, which is beneficial to ensuring root water absorption during the dry period. After compaction, the bulk density of the soil is 1.5 g / cm 3 。

[0047] Planting of gramineous plants and leguminous plants: After compaction, use a rotary tiller to till the soil. The tillage depth is 15 cm. After tillage, sow in the pattern of two rows of corn and two rows of soybeans. The row spacing between the two rows of corn is 30 cm, the hole spacing is 30 cm, and the hole depth is 2 cm. Sow 3 corn seeds in each hole; for the two rows of soybeans: with a row spacing of 30 cm, a hole spacing of 20 cm, a hole depth of 2 cm, and sow 2 soybean seeds in each hole.

[0048] Comparative Example 2

[0049] The difference between Comparative Example 2 and Example 1 is that soil compaction is not carried out. Specifically:

[0050] A method for improving saline-alkali land includes the following steps:

[0051] Land preparation: Plow the saline-alkali land to loosen the soil. After plowing, irrigate the land. The thickness of the water layer for irrigation is 8 cm. Loosen the soil before irrigation to make it easier for salts to penetrate downward.

[0052] Planting of gramineous plants and leguminous plants: Use a rotary tiller to till the land. The tillage depth is 15 cm. After tilling, sow in the pattern of two rows of corn and two rows of soybeans. The row spacing between the two rows of corn is 30 cm, the hole spacing is 30 cm, the hole depth is 2 cm, and 3 corn seeds are sown in each hole; for the two rows of soybeans: the row spacing is 30 cm, the hole spacing is 20 cm, the hole depth is 2 cm, and 2 soybean seeds are sown in each hole.

[0053] Comparative Example 3

[0054] The difference between Comparative Example 3 and Example 1 is that intercropping of corn and soybeans is not carried out. Specifically:

[0055] A method for improving saline-alkali land includes the following steps:

[0056] Land preparation: Plow the saline-alkali land to loosen the soil. After plowing, irrigate the land. The thickness of the water layer for irrigation is 5 cm to 8 cm. Loosen the soil before irrigation to make it easier for salts to penetrate downward.

[0057] Soil compaction: After the irrigation water dries, compact the soil. When compacting, use a tractor with a mechanical roller to roll the cultivated land multiple times to reduce the soil porosity and increase the soil firmness. In this way, increase the soil bulk density and the proportion of small pores to limit the downward movement of soil water and gas and the upward migration of underground water after compaction, establish a "barrier layer" for the repeated evaporation movement of salts with water, and at the same time inhibit the downward growth of crop roots and promote the lateral development of roots, which is beneficial to ensuring root water absorption during drought periods. After compaction, the soil bulk density is 1.5 g / cm 3 .

[0058] Planting of leguminous plants: Use a rotary tiller to till the land. The tillage depth is 15 cm. After tilling, sow soybeans. The row spacing is 30 cm, the hole spacing is 20 cm, the hole depth is 2 cm, and 2 soybean seeds are sown in each hole.

[0059] Comparative Example 4

[0060] The difference between Comparative Example 4 and Example 1 is that when intercropping corn and soybeans, there are two rows of corn and four rows of soybeans. Specifically:

[0061] A method for improving saline-alkali land includes the following steps:

[0062] Land preparation: Plow the saline-alkali land to loosen the soil. After plowing, irrigate the land. The thickness of the water layer for irrigation is 8 cm. Plow the land before irrigation to make the soil porous, so that salts can penetrate downward more easily.

[0063] Soil compaction: After the water has dried in the irrigated soil, compact the soil. When compacting, use a tractor with a mechanical roller to roll the cultivated land multiple times to reduce the soil porosity and increase the soil firmness. In this way, increase the soil bulk density and the proportion of small pores to limit the downward movement of soil water and gas and the upward migration of groundwater, establish a "barrier layer" for the repeated evaporation movement of salts with water, and at the same time inhibit the downward growth of crop roots and promote the lateral development of roots, which is beneficial to ensure root water absorption during the dry period. After compaction, the bulk density of the soil is 1.5 g / cm 3 。

[0064] Planting of gramineous plants and leguminous plants: After compaction, use a rotary tiller to till the soil. The tillage depth is 15 cm. After tillage, sow in the pattern of two rows of corn and four rows of soybeans. The row spacing between the two rows of corn is 30 cm, the hole spacing is 30 cm, and the hole depth is 2 cm. Sow 3 corn seeds in each hole; For the four rows of soybeans: at a row spacing of 30 cm, a hole spacing of 20 cm, and a hole depth of 2 cm, sow 2 soybean seeds in each hole.

[0065] After being improved by Examples 1 to 3 and Comparative Examples 1 to 4, collect soil samples. Denote the soil without improvement as CK and conduct physical and chemical index tests on the soil. The results are shown in Tables 1 and 2.

[0066] Table 1 Physical and chemical properties of the 0-20 cm soil layer after the experiment

[0067]

[0068] As can be seen from Table 1, the pH value of Comparative Example 4 is greater than that of Comparative Example 3. When 4 rows of soybeans are planted in the middle of the corn, the degree of pH reduction is the smallest and is even higher than the pH value of only planting soybeans. This may be because no mutually promoting relationship has been formed between the roots of corn and soybeans, resulting in competition in the growth of corn and soybeans, and each absorbing the nutrients in the soil, leading to soil deterioration.

[0069] The soil salt content of Comparative Example 4 is greater than that of Comparative Example 3. When 4 rows of soybeans are planted in the middle of the corn, the degree of soil salt content reduction is the smallest and is even higher than the soil salt content of only planting soybeans. This is the same as the change trend of pH, further indicating that the growth of corn and soybeans may form competition, leading to soil deterioration.

[0070] The pH value of Comparative Example 1 was less than that of CK but greater than the pH values of Examples 1 to 3. That is, only soil compaction and intercropping of corn and soybeans reduced the soil pH value, but the degree of reduction was less than that of plowing and irrigation before soil compaction. This shows that plowing and irrigation before soil compaction can promote the downward penetration of salts and form a barrier layer.

[0071] The pH value of Comparative Example 2 was less than that of CK but greater than the pH values of Examples 1 to 3. That is, only land preparation and intercropping of corn and soybeans reduced the soil pH value, but the degree of reduction was less than that of soil compaction and planting after land preparation. Moreover, the degree of reduction of the pH value in Comparative Example 2 was less than that in Comparative Example 1. This shows that although plowing and irrigation can promote the downward penetration of salts, without soil compaction, no barrier layer is formed. On the one hand, during the growth of corn and soybeans, the roots develop downward and the lateral development weakens, reducing the interaction between the roots of soybeans and corn. On the other hand, it causes the upward movement of the downward-permeated salts, resulting in an increase in pH.

[0072] The soil salt content in Comparative Example 2 was greater than that in Comparative Example 1, which is the same as the pH change trend between Comparative Example 2 and Comparative Example 1, further illustrating the interrelationship among land preparation, soil compaction, and corn-soybean intercropping.

[0073] The pH value of Comparative Example 3 was less than that of CK but greater than the pH values of Examples 1 to 3. That is, only land preparation and soil compaction reduced the soil pH value, but the degree of reduction was less than that of soil compaction and planting after land preparation. Moreover, the degree of reduction of the pH value in Comparative Example 3 was less than that in Comparative Example 1. This shows that although land preparation and compaction can promote the downward penetration of salts and form a barrier layer, without the interaction between the roots of corn and soybeans, it is impossible to improve soil quality by utilizing the root habits.

[0074] The soil salt content in Comparative Example 3 was greater than that in Comparative Example 1, which is the same as the pH change trend between Comparative Example 3 and Comparative Example 1, further illustrating the interrelationship among land preparation, soil compaction, and corn-soybean intercropping.

[0075] Table 2 Physical and Chemical Properties of Soil in the 20 cm - 40 cm Soil Layer after the Experiment

[0076]

[0077] Fertilization treatments were carried out for each treatment. The fertilizer used was decomposed farmyard manure. Fertilization trenches with a depth of 15 cm and a width of 10 cm were dug between two rows of corn, and farmyard manure was applied in the trenches at a rate of 2 tons per mu. After fertilization and growth, the yields of corn and soybeans were counted.

[0078] Table 3 Plant growth indicators

[0079] Group Maize yield per mu / kg 100-grain weight of maize / g Soybean yield per mu / kg 100-grain weight of soybean / g Example 1 513.57 29.14 134.41 26.06 Example 2 503.13 29.08 130.40 25.97 Example 3 499.08 29.00 127.09 25.90 Comparative Example 1 487.61 28.54 125.88 25.73 Comparative Example 2 481.09 28.49 124.65 25.69 Comparative Example 3 477.93 28.10 124.01 25.55 Comparative Example 4 471.32 28.03 123.34 25.48

[0080] By jointly analyzing the yield and the nitrate nitrogen, ammonium nitrogen, and organic matter in Table 1 and Table 2, it can be seen that after improvement using the methods of Examples 1 to 3 of the present invention, the nitrate nitrogen, ammonium nitrogen, and organic matter increase, thereby increasing the yields of corn and soybeans.

[0081] After two consecutive years of improvement using the methods of Comparative Examples 1 to 4 of Examples 1 to 3, the physical and chemical properties of the 0-20 cm soil layer were measured again, as shown in Table 4.

[0082] Table 4 Physical and chemical properties of the 0 cm - 20 cm soil layer after the experiment

[0083]

[0084] As can be seen from Table 3, the pH value of Comparative Example 4 is greater than that of Comparative Example 3. When 4 rows of soybeans are interplanted among the corn, the degree of pH reduction is the smallest, even higher than the pH value of only planting soybeans. This may be because no mutually promoting relationship is formed between the corn roots and the soybean roots, resulting in competition between the growth of corn and soybeans for absorbing soil nutrients, leading to soil deterioration.

[0085] The soil salt content of Comparative Example 4 is greater than that of Comparative Example 3. When 4 rows of soybeans are interplanted among the corn, the degree of soil salt content reduction is the smallest, even higher than the soil salt content of only planting soybeans. This is the same as the change trend of pH, further indicating that the growth of corn and soybeans may form competition, leading to soil deterioration.

[0086] The pH value of Comparative Example 1 is less than that of CK but greater than the pH values of Examples 1 to 3. That is, only soil compaction and the intercropping of corn and soybeans reduce the soil pH value, but the reduction degree is less than that of plowing and irrigation before soil compaction. This shows that plowing and irrigation before soil compaction can promote the downward penetration of salts and form a barrier layer.

[0087] The pH value of Comparative Example 2 is less than that of CK but greater than the pH values of Examples 1 to 3. That is, only land preparation and the intercropping of corn and soybeans reduce the soil pH value, but the degree of reduction is less than that of soil compaction and planting after land preparation. Moreover, the degree of reduction of the pH value in Comparative Example 2 is less than that in Comparative Example 1, indicating that although plowing and irrigation can promote the downward penetration of salts, without soil compaction, no barrier layer is formed. On the one hand, during the growth of corn and soybeans, the roots develop downward, and the lateral development weakens, reducing the interaction between the roots of soybeans and corn. On the other hand, it causes the upward movement of the downward-permeated salts, resulting in an increase in pH.

[0088] The soil salt content of Comparative Example 2 is greater than that of Comparative Example 1, which is the same as the pH change trend between Comparative Example 2 and Comparative Example 1, further illustrating the interrelationship among land preparation, soil compaction, and the intercropping of corn and soybeans.

[0089] The pH value of Comparative Example 3 is less than that of CK but greater than the pH values of Examples 1 to 3. That is, only land preparation and soil compaction reduce the soil pH value, but the degree of reduction is less than that of soil compaction and planting after land preparation. Moreover, the degree of reduction of the pH value in Comparative Example 3 is less than that in Comparative Example 1, indicating that although land preparation and compaction can promote the downward penetration of salts and form a barrier layer, without the interaction between the roots of corn and soybeans, the habit of the roots cannot be used to improve the soil quality.

[0090] The soil salt content of Comparative Example 3 is greater than that of Comparative Example 1, which is the same as the pH change trend between Comparative Example 3 and Comparative Example 1, further illustrating the interrelationship among land preparation, soil compaction, and the intercropping of corn and soybeans.

[0091] The data in the second year and the soil physical and chemical data in the first year show the same change trend as the soil physical and chemical data in the first year, further illustrating the interrelationship among land preparation, soil compaction, and the intercropping of corn and soybeans in the improvement of saline-alkali land in the present invention.

[0092] It should be noted that when the claims of the present invention involve numerical ranges, it should be understood that any value between the two endpoints of each numerical range and the two endpoints can be selected. To avoid redundancy, preferred embodiments of the present invention are described.

[0093] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0094] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A method for improving saline-alkali land, characterized in that, It includes the following steps: Land preparation: Plow the land and then irrigate it. Soil compaction: Compact the soil after it dries in the air. Planting of gramineous plants and leguminous plants: After rotary tillage, intercropping of gramineous plants and leguminous plants is carried out, and the distance between adjacent gramineous plants and leguminous plants is 30 cm to 45 cm.

2. The saline-alkali land improvement method according to claim 1, wherein When planting the gramineous plants and leguminous plants, the method of two to three rows of gramineous plants and two rows of leguminous plants is adopted.

3. The saline-alkali land improvement method according to claim 2, characterized in that, The row spacing of the gramineous plants is 30 cm to 40 cm, and the row spacing of the leguminous plants is 30 cm to 40 cm.

4. The saline-alkali land improvement method according to claim 1, characterized in that, After compaction, the bulk density of the soil is 1.5 g / cm 3 ~1.7 g / cm 3 .

5. The saline-alkali land improvement method according to claim 1, characterized in that, The thickness of the irrigation layer for the irrigation is 5 cm to 8 cm.

6. The saline-alkali land improvement method according to claim 1, wherein Fertilization is carried out after planting the gramineous plants and leguminous plants.

7. The saline-alkali land improvement method according to claim 6, characterized in that, The fertilization is the application of farmyard manure.

8. The saline-alkali land improvement method according to claim 1, wherein, In the saline-alkali land, the pH is 7.5 to 9.5, and the soil salt content is 0.4% to 0.55%.

9. The saline-alkali land improvement method according to claim 1, wherein, The gramineous plant is corn.

10. The saline-alkali land improvement method according to claim 1, characterized in that, The leguminous plant is soybean.

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