Saline-alkali soil sorghum hybrid sudangrass and sesbania banded planting method

Abstract

The invention discloses a strip-shaped planting method for sorghum sudanense and sesbania in saline-alkali soil, and belongs to the technical field of forage grass planting. The strip-shaped planting method for the sorghum sudangrass and the sesbania in the saline-alkali soil comprises the step of carrying out strip-shaped planting on the sorghum sudangrass and the sesbania in a strip-shaped planting mode of four rows of the sorghum sudangrass and two rows of the sesbania. The strip-shaped planting of the sorghum hybrid sudangrass and the sesbania adopts a dry sowing and wet emergence cultivation mode of drip irrigation under a film and precision sowing on the film. Through strip planting of the sorghum hybrid sudangrass and sesbania, the group character, forage grass quality and production capacity of the sorghum hybrid sudangrass are remarkably improved, the main performance is that the plant height and stem diameter of the sorghum hybrid sudangrass are increased, and the fresh grass yield, crude protein content, total volatile fatty acid and dry matter disappearance rate of mixed forage grass are improved; meanwhile, the sorghum hybrid sudangrass and sesbania mixed forage grass obtained by cutting can be directly ensiled or directly fed to livestock. According to the strip-shaped planting method for the sorghum hybrid sudangrass and the sesbania, the group character, the forage grass quality and the production capacity of the sorghum hybrid sudangrass can be improved, and the saline-alkali soil can also be improved.

Description

Technical Field

[0001] The invention relates to the technical field of forage grass planting, in particular to a strip planting method of sorghum and sesbania in saline-alkali land. Background Art

[0002] In recent years, the salinization of land, desertification of soil and shortage of fresh water resources in the arid northwest region of my country have further intensified, seriously affecting and restricting the area of ​​forage cultivation, while also significantly reducing its yield and quality. The salinized cultivated land area in Xinjiang has reached 27.28 million mu, accounting for 25.8% of the total cultivated land area, of which 12.11 million mu (moderately salinized area) urgently needs to be improved and managed, mainly distributed in southern Xinjiang areas such as Aksu and Kashgar. Due to the small amount of available cultivated land per capita, the shortage of water resources and the serious shortage of forage production in southern Xinjiang, the introduction and breeding of new drought-resistant and salt-alkali tolerant forage varieties and green and efficient cultivation models are the key to efficient use of water resources and forage production in the region.

[0003] There are relatively few types of legumes and grasses suitable for planting on saline-alkali land. Currently, there are crops such as oats, sorghum, sesbania, and alfalfa. Sorghum (Sorghum Bicolor x S. Sudanense) is a crop with strong tolerance to abiotic stress and high water use efficiency, strong digestion and regeneration ability, salt and alkali tolerance, rich in soluble carbohydrates, and can save more than 30% water and more than 10% nitrogen fertilizer than corn. Sesbania (Sesbania cannabina) is an annual herbaceous plant of the genus Sesbania in the Leguminosae family. It has a high crude protein content, strong nitrogen fixation ability, salt tolerance, waterlogging tolerance, barrenness tolerance, drought tolerance, and strong resistance to diseases and insects. It can grow on saline soil with a soil salt content of 0.6% or on alkaline soil with a pH value of 9.5. Sorghum and sesbania have the potential to be planted on saline-alkali land. However, previous studies on sorghum and sesbania were mainly based on single sowing or mixed sowing with other crops; but in mixed sowing systems, there is competition between crops for resources such as light and temperature, and in semi-arid areas, underground interspecific competition is crucial to increasing yields and maintaining the long-term function of the system; the traditional single forage crop planting model has higher planting costs than mixed cropping, and lower overall benefits. Therefore, it is necessary to develop new planting patterns for sorghum and sesbania. Intercropping of different forages has the advantages of improving system productivity, preventing lodging, and high resource utilization, and can achieve better ecological and economic benefits. There have been no reports on the intercropping strip configuration of sorghum and sesbania in the prior art, and the study of strip planting methods of sorghum and sesbania suitable for saline-alkali land has broad development prospects. Summary of the invention

[0004] The purpose of the present invention is to provide a strip planting method of sorghum and sesbania in saline-alkali land to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is a strip planting method of sorghum and sesbania in saline-alkali land, which carries out strip planting of sorghum and sesbania in a strip planting mode of 4 rows of sorghum + 2 rows of sesbania.

[0007] That is, 4 rows of sorghum are planted on one sorghum planting belt, and 2 rows of sesbania are planted on one sesbania planting belt, and the sorghum planting belts and the sesbania planting belts are arranged alternately.

[0008] Strip planting of sorghum and sesbania can significantly improve the group traits of sorghum, the quality of mixed forage and production capacity. This is due to the formation of more marginal effects. Sorghum grows fast and the plants are tall, while sesbania grows relatively slowly and the plants are relatively short. It can form a wave-like pattern during the growth period, which increases more margins, promotes the growth of sorghum, improves resource utilization efficiency, and increases land equivalent ratio. Moreover, the row ratio of sorghum to sesbania of 4:2 is consistent with the root characteristics of the two and the reasonable spatial utilization rate of the soil, which has a more obvious effect on improving the group traits of sorghum, the quality of mixed forage and production capacity. At the same time, strip planting of sorghum and sesbania can also improve saline-alkali land, reduce soil pH, reduce soil salt content, increase soil microbial diversity, and increase soil organic matter content.

[0009] Furthermore, the strip planting of sorghum and sesbania adopts a dry-seeding and wet-out cultivation method with drip irrigation under the film and precision seeding on the film.

[0010] The drip irrigation under the film and the precision seeding cultivation method on the film can keep the soil loose and in the best moisture state, and the water consumption is small, which is only 50% of the conventional irrigation.

[0011] Furthermore, the row spacing of the sorghum is 60 cm, and the plant spacing is 15 cm; the row spacing of the sesbania is 60 cm, and the plant spacing is 15 cm; the row spacing between the sorghum and the sesbania is 60 cm.

[0012] Furthermore, the sorghum and the sesbania are sown and mowed simultaneously; and the sowing is carried out in spring or summer.

[0013] Furthermore, before sowing, 320 kg·hm of compound fertilizer was applied. -2 .

[0014] Furthermore, the compound fertilizer consists of urea and diammonium phosphate, and the mass ratio of the urea to diammonium phosphate is 3:1.

[0015] Furthermore, the method further comprises a step of intertillage after sowing, wherein the intertillage comprises: intertillage is performed during the germination stage and the seedling stage of sorghum and sesbania, respectively, and the soil depth is 10-15 cm.

[0016] Furthermore, the mowing is carried out twice a year.

[0017] Furthermore, the step of water and fertilizer management is also included after sowing, and the water and fertilizer management includes: dripping water 6 times from the sowing day to the heading period before the first mowing, with a total dripping amount of 3525m 3 ·hm -2 , apply top dressing while dripping water; after the first mowing, drip water and apply top dressing fertilizer every 15 to 20 days.

[0018] Furthermore, from the sowing date to the heading period before the first mowing, water was dripped 6 times in total, with a total dripping amount of 3525m 3 ·hm -2 , topdressing at the same time as dripping includes: the first dripping on the day after sowing (the day of sowing is regarded as day 0 after sowing), the dripping volume is 200m 3 ·hm -2 ; The second dripping was carried out on the 4th day after sowing, with a dripping volume of 175m 3 ·hm -2 , drip irrigation 1-2kg / mu wood vinegar; the third drip irrigation is carried out 45-60 days after sowing, with a drip volume of 900m 3 ·hm -2 , urea 150kg·hm -2 and diammonium phosphate 75kg·hm -2 ; The fourth dripping is carried out on the 61st to 70th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ; The fifth dripping is carried out on the 80th to 90th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ; The sixth dripping was carried out on the 91st to 100th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ;

[0019] And / or, after the first mowing, watering and topdressing every 15 to 20 days include: each dripping amount is 750m 3 ·hm -2 , urea 225kg·hm -2 .

[0020] Furthermore, the sowing is carried out in early April.

[0021] The second technical solution of the present invention is a method for improving saline-alkali land, in which sorghum and sesbania are planted in strips on saline-alkali land in a strip planting pattern of 4 rows of sorghum + 2 rows of sesbania.

[0022] The present invention discloses the following technical effects:

[0023] The present invention significantly improves the characteristics of the sorghum population, forage quality and production capacity through strip planting of sorghum and sesbania, which is mainly manifested in the increase of sorghum plant height and stem thickness, and the increase of fresh grass yield, crude protein (CP) content, total volatile fatty acids (TVFA) and dry matter disappearance rate (DMD) of the mixed forage, with the same performance from year to year. Specifically, under the S4C2 strip planting mode, the sorghum plant height increased by 7.94-33.04%; the fresh grass yield was as high as 125.13 t·hm -2 (2023), 129.20t·hm -2 (2024), significantly increased by 20.56% and 13.79% compared with MS (P < 0.05); crude protein content increased by 14.25-32.64%, crude fat (EE) and crude ash (Ash) content also increased to varying degrees; acetic acid, propionic acid and valeric acid concentrations increased, total volatile fatty acids, dry matter disappearance rate increased significantly by 3.80% and 19.30%, respectively (P < 0.05). Moreover, under the S4C2 strip planting mode, in addition to improving the group traits, forage quality and production capacity of sorghum, it can also improve the soil conditions of saline-alkali land. The 4:2 strip planting mode between sorghum and sesbania is suitable for promotion and application in arid desert oasis areas such as southern Xinjiang.

[0024] The high dan grass and sesbania mixed forage obtained in the S4C2 strip planting mode of the present invention is rich in nutrients, high in content, high in dry matter disappearance rate, easily digested and absorbed by animals, and conducive to increasing the animal feed intake, and can provide sufficient nutrition for animal growth. Therefore, in the high dan grass and sesbania S4C2 strip planting mode of the present invention, the high dan grass and sesbania mixed forage obtained by mowing at the same time can be directly ensiled or directly fed to livestock during mowing, which can not only greatly reduce production and production costs, but also improve silage quality. The prepared silage can meet the growth needs of animals without the need to cooperate with other forages, especially the feed nutrition needs that can meet the optimal production performance of ruminant livestock. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 Schematic diagram of different planting modes (MS, MC, S2C2, S4C2, S4C4, S6C4) in Example 1 and Comparative Examples 1-5;

[0027] Figure 2 The growth conditions of sorghum and sesbania in the S4C2 strip planting mode in Example 1 at the first mowing in 2023;

[0028] Figure 3 The test results of fresh grass yield of four crops in 2023 and 2024 under different planting modes of Example 1 and Comparative Examples 1-5 are as follows;

[0029] Figure 4 This is a radar chart for comprehensive evaluation of yield and quality of sorghum and sesbania in different planting modes in Example 1 and Comparative Examples 1-5. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0032] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0033] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0034] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0035] As a first aspect of the present invention, the present invention provides a strip planting method of sorghum and sesbania in saline-alkali land, wherein the strip planting of sorghum and sesbania is carried out in a strip planting mode of 4 rows of sorghum + 2 rows of sesbania.

[0036] As an embodiment of the present invention, the strip planting of sorghum and sesbania adopts a dry-seeding and wet-out cultivation method of drip irrigation under the film and precision seeding on the film.

[0037] As a preferred embodiment of the present invention, the strip planting method of sorghum and sesbania in saline-alkali land comprises the following steps:

[0038] (1) Setting up a strip planting pattern: The strip planting pattern of sorghum and sesbania is 4 rows of sorghum + 2 rows of sesbania, with sorghum planting strips and sesbania planting strips arranged alternately, with the row spacing of sorghum and sesbania being 60 cm, the plant spacing being 15 cm, and the row spacing between sorghum and sesbania being 60 cm;

[0039] (2) Sowing: Sorghum and Sesbania were sown simultaneously according to the set strip planting pattern. Before sowing, 320 kg·hm2 of compound fertilizer (urea and diammonium phosphate, with a mass ratio of 3:1) was applied. -2 ;

[0040] (3) Intertillage: Intertillage should be carried out during the germination and seedling stages of forage grass, with the soil depth of 10-15 cm;

[0041] (4) Water and fertilizer management: From the sowing day to the heading period before the first mowing, water was dripped 6 times, with a total dripping volume of 3525m 3 ·hm -2 , topdressing is carried out at the same time as dripping water; specifically, the first dripping water is carried out on the day after sowing, with a dripping volume of 200m 3 ·hm -2 ; The second dripping was carried out on the 4th day after sowing, with a dripping volume of 175m 3 ·hm -2 , drip irrigation 1-2kg / mu wood vinegar; the third drip irrigation is carried out 45-60 days after sowing, with a drip volume of 900m 3 ·hm -2 , urea 150kg·hm -2 and diammonium phosphate 75kg·hm -2 ; The fourth dripping is carried out on the 61st to 70th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2; The fifth dripping is carried out on the 80th to 90th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ; The sixth dripping was carried out on the 91st to 100th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ;

[0042] (5) Water and fertilizer management after the first mowing: The first mowing of sorghum and sesbania (generally, the first mowing is carried out 100 days after sowing or after sorghum heads, and sorghum and sesbania are mowed together at the same time). After the first mowing, water and topdress every 15 to 20 days, including: 750 m3 of water per time 3 ·hm -2 , urea 225kg·hm -2 ;

[0043] (6) Second mowing: The second mowing of sorghum and sesbania (generally, the second mowing is carried out 60 to 70 days after the first mowing, or after the sorghum has headed. When mowing, sorghum and sesbania are mowed together at the same time).

[0044] As a preferred embodiment of the present invention, the sowing is carried out in early April.

[0045] As a second aspect of the present invention, the present invention provides a method for improving saline-alkali land, wherein sorghum and sesbania are planted in strips on the saline-alkali land in a strip planting pattern of 4 rows of sorghum + 2 rows of sesbania.

[0046] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0047] The planting tests of the following embodiments and comparative examples of the present invention were all carried out in a test field under the same conditions. The test field is as follows: The test field is located in Aral City, Xinjiang, and has a typical warm temperate continental arid climate. The area is rich in light and heat resources, with an annual radiation of 9733MJ·m -2 The annual average sunshine hours are 2650-3100h, the annual average temperature is 10.4℃, the extreme maximum temperature is 40.6℃, the extreme minimum temperature is -23.4℃, the frost-free period is 180-224d, the annual accumulated temperature greater than or equal to 10℃ is 3800-4700℃, the annual average precipitation is 40-70mm, and the annual average evaporation is greater than 2100mm. The soil is sandy, alkaline, with a pH value of 8.3 (saline-alkali land), and the terrain is flat.

[0048] The following embodiments and comparative examples of the present invention all adopt the method of drip irrigation under the membrane and precision seeding on the membrane. The cultivation and planting experiments were carried out for two consecutive years from 2023 to 2024. The planting area of ​​each embodiment and comparative example is 72m 2 A single-factor randomized block experimental design was constructed between each embodiment and comparative example.

[0049] Example 1 (sorghum and sesbania S4C2 strip planting pattern, the planting pattern diagram is as follows Figure 1 (shown)

[0050] A method for strip planting of sorghum and sesbania in saline-alkali land, comprising the following steps:

[0051] (1) Setting up a strip planting pattern: The strip planting pattern of sorghum and sesbania is 4 rows of sorghum + 2 rows of sesbania, that is, 4 rows of sorghum are planted in one sorghum planting strip, and 2 rows of sesbania are planted in one sesbania planting strip (that is, the row ratio of sorghum to sesbania is 4:2). The sorghum planting strips and sesbania planting strips are arranged alternately, and the row spacing of sorghum and sesbania is 60 cm, the plant spacing is 15 cm, and the row spacing between sorghum and sesbania is also 60 cm.

[0052] (2) Sowing: On April 10, 2023, sorghum and sesbania were sown simultaneously according to the set strip planting pattern. Before sowing, 320 kg·hm2 of compound fertilizer (urea and diammonium phosphate, with a mass ratio of 3:1) was applied. -2 .

[0053] (3) Intertillage: Intertillage should be carried out during the germination and seedling stages of forage grass, with the soil depth being 15 cm.

[0054] (4) Water and fertilizer management: Sowing was carried out on April 10, and the first dripping was carried out the day after sowing, with a dripping volume of 200m 3 ·hm -2 ; The second dripping was carried out on the 4th day after sowing, with a dripping volume of 175m 3 ·hm -2 , drip wood vinegar 1.5kg / mu, drip for the third time on the 50th day after sowing, dripping amount 900m 3 ·hm -2 , urea 150kg·hm -2 and diammonium phosphate 75kg·hm -2 ; The fourth dripping was carried out 65 days after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ; The fifth dripping was carried out on the 85th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2; The sixth dripping was carried out on the 90th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 .

[0055] (5) First mowing and water and fertilizer management after the first mowing: The first mowing was carried out on July 20 (the growth conditions at the time of the first mowing were as follows: Figure 2 When mowing, mix sorghum and sesbania at the same time. After the first mowing, water and topdress every 15 days (drip volume 750m 3 ·hm -2 , urea 150kg·hm -2 ).

[0056] (6) Second mowing: The second mowing was carried out on September 20, and sorghum and sesbania were mixed and mowed at the same time.

[0057] After tilling the soil in 2024, repeat the above steps in 2023.

[0058] Comparative Example 1 (S2C2 strip planting pattern of sorghum and sesbania, the planting pattern diagram is as follows Figure 1 (shown)

[0059] The same as Example 1, except that the strip planting pattern of sorghum and sesbania is set to 2 rows of sorghum + 2 rows of sesbania, that is, 2 rows of sorghum are planted on one sorghum planting strip, and 2 rows of sesbania are planted on one sesbania planting strip (that is, the row ratio of sorghum to sesbania is 2:2), and the sorghum planting strips and sesbania planting strips are arranged alternately.

[0060] Comparative Example 2 (S4C4 strip planting pattern of sorghum and sesbania, the planting pattern diagram is as follows Figure 1 (shown)

[0061] The same as Example 1, except that the strip planting pattern of sorghum and sesbania is set to 4 rows of sorghum + 4 rows of sesbania, that is, 4 rows of sorghum are planted on one sorghum planting strip, and 4 rows of sesbania are planted on one sesbania planting strip (that is, the row ratio of sorghum to sesbania is 4:4), and the sorghum planting strips and sesbania planting strips are arranged alternately.

[0062] Comparative Example 3 (sorghum and Sesbania S6C4 strip planting pattern, the planting pattern diagram is as follows Figure 1 (shown)

[0063] The same as Example 1, except that the strip planting pattern of sorghum and sesbania is set to 6 rows of sorghum + 4 rows of sesbania, that is, 6 rows of sorghum are planted on one sorghum planting strip, and 4 rows of sesbania are planted on one sesbania planting strip (that is, the row ratio of sorghum to sesbania is 6:4), and the sorghum planting strips and sesbania planting strips are arranged alternately.

[0064] Comparative Example 4 (single sowing of sorghum, the planting mode is referred to as MS, as shown in the schematic diagram Figure 1 (shown)

[0065] Same as Example 1, except that only sorghum was sown, and the sowing rate of sorghum was 10.14 kg·hm -2 , the other operation steps are the same as those in Example 1.

[0066] Comparative Example 5 (Single Planting of Sesbania sesbania, Planting Mode is referred to as MC, as shown in the schematic diagram Figure 1 (shown)

[0067] Same as Example 1, except that only sesbania was sown, and the sowing rate of sesbania was 11.4 kg·hm -2 , the other operation steps are the same as those in Example 1.

[0068] Comparative Example 6

[0069] Sorghum and silage corn were planted in strips (4:2), and the steps were the same as in Example 1, except that sesbania was replaced by silage corn.

[0070] Comparative Example 7 (Silage Corn Single Planting)

[0071] Same as Example 1, except that only silage corn is sown, and the sowing rate of silage corn is 45 kg·hm -2 , the other operation steps are the same as those in Example 1.

[0072] Test Example 1

[0073] Tests on the growth of sorghum and sesbania

[0074] During the test, WPS2023 was used to process data and SPSS27.0 analysis software was used for one-way ANOVA analysis of variance. The Duncan method was used for multiple comparisons. The results were expressed as mean ± standard error. P < 0.05 indicated significant differences between different treatments. Origin software was used to draw fresh grass yield maps and comprehensive analysis radar maps.

[0075] 1. Determination of fresh grass yield and agronomic traits

[0076] (1) Test method

[0077] On July 20 (first crop) and September 20 (second crop) of each year, single seeding treatment (comparative example 4 and comparative example 5) with an area of ​​4.6m 2 (2m×2.3m), the strip planting pattern area S2C2 (Comparative Example 1) is 6m 2(2m×3m), S4C2 (Example 1) is 9.1m 2 (2m×4.55m), S4C4 (Comparative Example 2) is 12m 2 (2m×6m), S6C4 (Comparative Example 3) is 15.2m 2 The test plots were 2m×7.6m. In each plot, the whole plant was cut from 10cm above the ground, and the fresh weight was calculated by plot, which was repeated 3 times. At the same time, 1kg of fresh forage (sorghum and / or sesbania) was randomly placed in a mesh bag in each test plot, dried in the shade, and used for the determination of conventional nutrient content and other indicators, and the results were averaged.

[0078] At the same time, 10 individual sorghum and sesbania were randomly selected from the evenly growing part of each test plot, and the natural height (the height from the ground to the highest part of the plant), the stem diameter of sorghum (the middle diameter from the second to the third stem node from the ground was measured using a digital vernier caliper), the number of stem nodes and the total number of leaves were measured, and the average value was calculated.

[0079] (2) Test results

[0080] The test results of the fresh grass yield of four crops in 2023 and 2024 under different planting modes in Example 1 and Comparative Examples 1-5 (the fresh grass yield of mixed sorghum + sesbania in the strip planting mode) are as follows Figure 3 As shown in the figure, MS is a single-sowing sorghum treatment (Comparative Example 4), MC is a single-sowing sesbania treatment (Comparative Example 5), S2C2, S4C2, S4C4, S6C4 are strip planting patterns under the row ratio of sorghum to sesbania 2:2 (Comparative Example 1), 4:2 (Example 1), 4:4 (Comparative Example 2), and 6:4 (Comparative Example 3), respectively. Different lowercase letters indicate significant differences in the average yields of the two years (P < 0.05), and the same letters indicate no significant differences (P > 0.05). Figure 3 It can be seen that strip planting can significantly increase fresh grass yield, showing a trend of S4C2>S2C2>S4C4>MS>S6C4>MC. The maximum fresh grass yield of S4C2 in two years was 125.13 t·hm -2 (2023), 129.20t·hm -2 (2024), which was significantly increased by 20.56% and 13.79% (P < 0.05) compared with MS. The average fresh grass yield of S4C2 in the two years was 127.16 t·hm -2 , which was significantly increased by 17.03% (P<0.05) compared with MS. The average fresh grass yield of S2C2 and S4C4 was 110.78t·hm -2 、110.68t·hm -2 , an increase of 1.95% and 1.86% compared with MS, and the fresh grass yield of S6C4 was 106.20t·hm -2, which is 2.26% lower than MS. The fresh grass yield of the second crop of forage in both years is higher than that of the first crop, and there is not much difference in the fresh grass yield of forage between 2024 and 2023.

[0081] The plant height test results of four crops of sorghum and sesbania in 2023 and 2024 under different planting patterns are shown in Table 1:

[0082] Table 1 Effects of planting patterns on plant height of sorghum and sesbania

[0083]

[0084] Note: Data in the same column with different letters on their shoulders indicate significant differences (P<0.05), and data with the same letters or no letters indicate no significant differences (P>0.05), the same below.

[0085] As shown in Table 1, in the four crops in two years, the plant height advantage of sedum was the most significant under the S4C2 treatment (P < 0.05). In 2023, the plant height of the first crop of sedum showed a trend of S4C2 > MS > S4C4 > S6C4 > S2C2, and the plant height of sesbania showed a trend of S6C4 > S4C2 > MC > S2C2 > S4C4. The plant height of sedum in S4C2 was significantly increased by 7.94% compared with the MS treatment (P < 0.05). The plant height of the second crop of sedum showed a trend of S4C2 > S2C2 > MS > S4C4 > S6C4, and the plant height of sedum in S4C2 was significantly increased by 17.16% compared with the MS treatment (P < 0.05). There was no significant difference in the plant height of sedum in other strip treatments with MS, and the plant height of sesbania showed a trend of MC > S4C2 > S4C4 > S2C2 > S6C4. In 2024, the plant height of the first crop of sorghum was S4C2>S4C4>S6C4>MS>S2C2, among which the plant height of sorghum in S4C2 increased significantly by 33.04% (P<0.05) compared with the MS treatment, and the plant height of sesbania showed a trend of S4C4>MC>S2C2>S4C2>S6C4; in the second crop, the plant height of sorghum was S4C2>S2C2>S4C4>S6C4>MS, and the plant height of sorghum in S4C2 increased significantly by 8.91% (P<0.05) compared with the MS treatment, and the plant height of sesbania showed a trend of MC>S4C2>S2C2>S4C4>S6C4, and the strip planting pattern was significantly lower than the MC treatment (P<0.05); but in the second crop of both years, the plant height of sesbania in S4C2 treatment was the highest. There was no significant difference in the plant height of sorghum and sesbania between years.

[0086] The agronomic trait test results of four crops of sorghum and sesbania in 2023 and 2024 under different planting patterns are shown in Table 2:

[0087] Table 2 Effects of planting patterns on agronomic traits of sorghum

[0088]

[0089] As shown in Table 2, there were significant differences in stem diameter, number of stem nodes and number of leaves between the two crops of sorghum in 2023 (P<0.05). In the first crop, the stem diameter of sorghum in S6C4 treatment was significantly higher than that in other treatments (P<0.05), an increase of 13.47% compared with MS treatment; in the second crop, the stem diameter of sorghum in S4C4 treatment was significantly higher than that in other treatments (P<0.05), an increase of 67.47% compared with MS treatment; in the first crop, the number of stem nodes in S2C2 treatment was the largest, and the number of leaves in S4C4 treatment was the largest, which increased significantly by 44.5% and 9.37% respectively compared with the first crop MS treatment (P<0.05); in the second crop, the number of stem nodes in S4C2 treatment was the largest, which increased significantly by 23.86% compared with the second crop MS treatment (P<0.05), and the number of leaves in all strip treatments was significantly lower than that in MS (P<0.05); the agronomic traits of sorghum such as stem diameter and number of stem nodes in the second crop were all improved compared with the first crop. There were significant differences in stem diameter between the two crops of sorghum in 2024 (P<0.05). The stem diameter of sorghum in the first crop S2C2 treatment was the thickest, and the stem diameter of sorghum in the second crop S6C4 treatment was the thickest, which was significantly increased by 45.83% and 22.62% (P<0.05) compared with the two crops MS treatments, respectively; the number of stem nodes of sorghum in S4C2 in the first crop was significantly increased by 12.5% ​​(P<0.05) compared with the first crop MS, and the number of leaves in S2C2 treatment was the largest; there were no significant differences in the number of stem nodes and leaves in the second crop (P>0.05), and the stem diameter of the second crop was lower than that of the first crop. There was little difference in the agronomic traits of sorghum between years.

[0090] In addition, the fresh grass yields of two crops in 2024 in Example 1, Comparative Example 4, Comparative Example 6 and Comparative Example 7 were compared, and the results are shown in Table 3.

[0091] Table 3 Yields of different planting patterns

[0092]

[0093] Note: For comparison in the same column, different letters indicate significant differences.

[0094] As shown in Table 3, the yield of the first crop of fresh grass (mixed fresh grass) planted in strips with sorghum sown in spring can reach 66.16 t·hm -2 The fresh grass yield is higher than that of silage corn single seeding and sorghum single seeding, but lower than that of sorghum and sesbania strip planting. The second crop of corn cannot be regenerated. The total annual yield of silage corn single seeding or sorghum and silage corn strip planting decreases significantly. In addition, the salt and alkali tolerance of silage corn is not as good as that of sorghum and sesbania, which causes a decrease in yield.

[0095] Therefore, based on the above-mentioned deficiencies in forage cultivation in saline-alkali land, the present invention has developed a strip planting technology of sorghum and sesbania, which can be planted on both slightly saline-alkali land and moderately saline-alkali land. Both have strong adaptability to saline-alkali land and strong forage regeneration ability, and the regeneration speed of the two forage varieties is comparable. Appropriate row ratio planting can form the maximum marginal benefit, and the forage produced is high in yield and excellent in quality.

[0096] 2. Routine nutrient determination of forage

[0097] (1) Test method

[0098] The naturally shade-dried forage (sorghum + sesbania mixed forage in strip planting mode) was crushed with a grinder and passed through a 40-mesh sieve. The crude protein (CP), crude fat (Ether extract, EE), neutral detergent fiber (NDF) and acid detergent fiber (ADF), and crude ash (Ash) contents of the forage were determined with reference to the "Quality Test Methods and Quality Management of Feed and Feed Additives". Repeat 3 times and take the average value.

[0099] (2) Test results

[0100] The test results of the nutritional composition of the mixed forage of sorghum and sesbania in four crops in 2023 and 2024 under different planting patterns are shown in Table 4:

[0101] Table 4 Effects of different planting patterns on forage nutrients

[0102]

[0103]

[0104] Note: The nutrient content of each treatment in the first crop is the average of the first crop in 2023 and the first crop in 2024; the nutrient content of each treatment in the second crop is the average of the second crop in 2023 and the second crop in 2024; in the inter-annual differences in the first crop, the value in 2023 is the average of the first crop of each treatment in 2023, and the value in 2024 is the average of the first crop of each treatment in 2024; the inter-annual difference data of the second crop have the same meaning as those of the first crop.

[0105] As shown in Table 4, the CP content of mixed forage in each strip planting treatment in the first crop of two years was significantly higher than that in the MS treatment (P < 0.05), showing a trend of MS < S2C2 < S4C2 < S6C4 < S4C4 < MC. The EE content was higher than that in the MS treatment and significantly higher than that in the MC treatment (P < 0.05). The ADF and Ash contents were significantly increased compared with the MS treatment (P < 0.05). There was no significant difference in NDF among the treatments (P > 0.05). There was no significant difference in the CP, EE, ADF and NDF contents in the first crop of forage between the two years. In the second crop of forage in both years, the CP content of mixed forage in each strip planting treatment was significantly higher than that in the MS treatment (P < 0.05), showing the trend of MS < S6C4 < S2C2 < S4C2 < S4C4 < MC. The EE content was higher than that in the MS and MC treatments, and the ADF, NDF and Ash contents were significantly increased compared with the MS / MC treatment (P < 0.05). The CP and Ash contents of the second crop of forage in 2024 were significantly lower than those in 2023 (P < 0.05), and there was no significant difference in EE, ADF and NDF contents (P > 0.05).

[0106] 3. Determination of total volatile fatty acids (Total VFA, TVFA) and calculation of dry matter disappearance rate (DMD)

[0107] (1) Test method

[0108] Weigh 1.0g of substrate (sorghum + sesbania mixed forage in strip planting mode) into a 145mL fermentation bottle and preheat it in a constant temperature incubator at 39.5℃. Take out the fermentation bottle and pass CO2 to ensure an anaerobic environment in the fermentation bottle. Add 60mL of artificial rumen microbial nutrient solution to each fermentation bottle, and place the fermentation bottle in a constant temperature incubator to simulate goat rumen fermentation. After 72h of fermentation, measure the pH value of the fermentation liquid with a pH meter (Leci pH SensorLE407). 0.6 mL of the supernatant was taken and placed in a measuring bottle. The peak area of ​​each volatile fatty acid in the fermentation broth sample was determined by gas chromatograph (TRACE 1310, Thermo Fisher Scientific, USA). The concentration of each volatile fatty acid was calculated based on the standard curve. The method was referred to "Wang M, Sun X Z, Janssen PH, et al. Responses of methane production and fermentation pathways to the increased dissolved hydrogen concentration generated by eight substrates in invitro ruminal cultures [J]. Animal Feed Science and Technology, 2014, 194: 1-11". The remaining fermentation broth was filtered with 300-mesh nylon gauze and placed in an aluminum box. It was dried at 105 °C to constant weight and used to calculate the dry matter disappearance rate in the sample according to formula (1).

[0109] DMD = (sample weight × dry matter content - residue weight) / (sample weight × dry matter content) × 100 (1)

[0110] (2) Test results

[0111] The test results of TVFA and DMD of four crops of sorghum and sesbania in 2023 and 2024 under different planting patterns are shown in Table 5:

[0112] Table 5 Effects of different planting patterns on forage quality

[0113]

[0114] Note: The data under each treatment are the average of four crops in 2023 and 2024; among the inter-annual differences, the values ​​in 2023 are the average of two crops of each treatment in 2023, and the values ​​in 2024 are the average of two crops of each treatment in 2024. LOS represents the level of significance; SEM represents the standard error of the mean.

[0115] As shown in Table 5, the strip planting pattern significantly affects the VFA content and DMD in the mixed forage (P < 0.05). After 72 hours of in vitro fermentation, the concentrations of acetic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid and total volatile fatty acids in the fermentation broth of S6C4 were the lowest. Under different strip planting patterns, the content of acetic acid, propionic acid, valeric acid, TVFA and DMD in S4C2 was the highest, and TVFA and DMD increased significantly by 3.80% and 19.30% respectively compared with MS (P < 0.05). MS was second with the highest content of isobutyric acid, butyric acid and isovaleric acid. There were significant differences in pH among the planting patterns (P < 0.05), with MC being the highest and S4C2 being the lowest at 6.08; TVFA and DMD were significantly reduced by 5.83% and 12.79% in 2024 compared with 2023 (P < 0.05).

[0116] 4. Determination of Land Equivalent Ratio (LER)

[0117] (1) Test method

[0118] LER represents the ratio of the yield of two or more crops intercropped to the yield of crops in the same farmland. When LER>1, it indicates intercropping advantage, that is, intercropping is more efficient than crops in the same farmland. LER is calculated according to formula (2).

[0119]

[0120] Where Y is and Y ic are the yields of sorghum and sesbania in the total area under the strip planting mode, Y ms and Y mc These are the yields of sorghum (S) and sesbania (C) under single sowing mode. When LER>1, intercropping has an advantage, and when LER<1, intercropping has no advantage.

[0121] (2) Test results

[0122] The LER test results of four crops of sorghum and sesbania in 2023 and 2024 under different planting patterns are shown in Table 6:

[0123] Table 6 Comparison of LER under different planting patterns of sorghum and sesbania

[0124]

[0125] As shown in Table 6, in all strip planting pattern systems with different row ratios of sorghum and sesbania, the LER was greater than 1, indicating that the yield of strip planting treatment was better than that of single sowing of sorghum and sesbania. The LER of strip planting treatments with different row ratios in the second crop in 2023 was higher than that of the first crop; in the second crop in 2024, the LER of S4C2 treatment was slightly lower than that of the first crop, and the LER of other treatments increased; the annual average LER of strip planting patterns with different row ratios showed a trend of S4C2>S4C4>S6C4>S2C2, among which S4C2 had the largest value of 1.23; there was no significant difference in LER between years.

[0126] 5. Comprehensive analysis of forage yield and quality

[0127] (1) Analysis method

[0128] The average fresh grass yield, CP, EE, ADF, NDF, Ash, TVFA, DMD and other 10 groups of data of each treatment in two years and four crops were used as evaluation indicators to comprehensively analyze the single seeding mode and the strip planting mode with different row ratios. The data were standardized according to formulas (3) and (4).

[0129] R ij =r0÷(r ij -r0|+r0) (3)

[0130] R ij =r ij / maxr ij (4)

[0131] In the formula, r ij is the original data of each evaluation index; r0 is the optimal value of the jth neutral evaluation index established according to the target and actual production situation; R ij It is the value after the evaluation index is standardized.

[0132] Calculation of comprehensive evaluation value: coefficient of variation C of each evaluation index i Value and weight W i The value is calculated by formula (5) and formula (6); the angle θ of each evaluation index is obtained according to formula (7) and (8): i and the angle α between two adjacent indicators i ; Calculate the area S of the polygonal radar chart surrounded by each evaluation index according to formula (9) and (10). The larger the value, the stronger the overall advantage of the variety, and vice versa.

[0133]

[0134] θ i =360W i (7)

[0135]

[0136] In the formula, C i , σ, and R are the coefficient of variation, standard deviation, and mean value of the i-th agronomic trait evaluation index, respectively; n is the number of evaluation indicators; W i and θ i are the weight and corresponding angle of the i-th agronomic trait evaluation index, α i is the angle between two adjacent indicators (i and j); S is the area of ​​the polygonal radar chart; L is the perimeter of the polygonal radar chart; i and j refer to two adjacent evaluation indicators.

[0137] (2) Test results

[0138] The average values ​​of fresh grass yield, nutritional quality and other indicators of each treatment of four crops in two years were comprehensively analyzed, and a radar chart was drawn based on the standardized data after treatment, as shown in the figure below. Figure 4 As shown in the figure, among the six treatments, the area enclosed by the radar chart of each strip planting treatment is relatively complete, indicating that the strip planting pattern is better than the single planting pattern; the larger the area value of each planting pattern in the radar chart analysis data, the better the yield of the planting pattern with this proportion. The results are S4C2>S2C2>S6C4>S4C4>MS>MC, indicating that S4C2 is the best strip planting ratio.

[0139] 6. Results Analysis

[0140] (1) Effects of planting patterns on fresh grass yield and agronomic traits of sorghum and sesbania

[0141] The strip planting pattern significantly increased the plant height of sorghum and sesbania (P < 0.05), and the average total fresh grass (mixed fresh grass) yield of S4C2 in two years reached 127.16 t·hm -2 , an increase of 17.03% compared with MS; the fresh grass yield in 2024 increased by 4.15% compared with 2023; with the increase of strip planting row ratio, the increase in forage yield did not keep rising. For example, the fresh grass yield of S6C4 was lower than that of S4C2. This is because the intercropping of Gramineae and Leguminosae forage can complement each other in ecological niches, give full play to the marginal effect, and make full use of land and light and heat resources to improve photosynthetic efficiency; but when the planting ratio increases further, the marginal effect will gradually decrease, causing the photosynthesis of sorghum and sesbania to decrease, resulting in a certain degree of decrease in yield. Therefore, the intercropping of sorghum and sesbania should choose a suitable row ratio mode.

[0142] (2) Effects of planting patterns on forage quality of sorghum and sesbania

[0143] The CP and Ash contents in the mixed forage of sorghum and sesbania strip planting were higher than those in the MS treatment. Since sesbania is a leguminous plant with high CP content, the CP content increased. The Ash content of the forage increased due to the long-term wind and dust in the southern Xinjiang terrain. The ADF and NDF contents in the mixed forage were slightly higher than those in the single-sowing control group.

[0144] In vitro fermentation is a method to evaluate feed digestibility. Gas production reflects the fermentability of feed and the activity of rumen microorganisms. The higher the nutritional value of the feed, the stronger the fermentation activity of the microorganisms and the higher the gas production. TVFA and DMD were the highest under S4C2 treatment. DMD is an important indicator for evaluating the nutritional value of forage. Its digestion and degradation degree is proportional to the nutritional value of forage. It is also an indicator reflecting the degree of degradation of feed in the digestive tract. Its value is affected by the cellulose content and lignification degree of the forage. The higher the value, the easier it is to digest in the rumen, and the greater the dry matter intake of the animal. In this study, the DMD under different strip planting patterns was 44.99-53.65%, all higher than single-sown sorghum; but TVFA was higher than MS only in S4C2 treatment, and its value gradually decreased to 116.99mmol·L -1 , which is much lower than MS, indicating that the forage digestibility is best under the S4C2 strip planting pattern.

[0145] (3) Impact of planting pattern on land equivalent ratio

[0146] Land equivalent ratio is an important indicator to measure land utilization rate. The land equivalent ratio LER of sorghum and sesbania in the strip planting mode is greater than 1, which has significant production advantages, and the land productivity is significantly improved. The land equivalent ratio LER of treatment S4C2 is the largest, and the yield advantage is stronger. The LER of the second crop is higher than that of the first crop, and the second year is higher than the first year. It can be seen that strip planting is beneficial to improving land productivity.

[0147] In summary, the strip planting pattern improves both forage yield and forage quality. Through comprehensive evaluation and analysis, the total fresh grass yield and nutritional quality of forage reach the optimal value at S4C2. Therefore, in the Aral region of Xinjiang (saline-alkali area), sowing can be carried out according to the S4C2 pattern of sorghum and sesbania, which can effectively improve the total forage yield and quality and achieve the goal of increasing economic benefits.

[0148] Test Example 2

[0149] Soil improvement test

[0150] The soil improvement conditions of Example 1 and Comparative Example 6 were tested after four mowings in 2023 and 2024, and the soil conditions before the planting test were used as a control. The soil conditions of Example 1 and Comparative Example 6 before the planting test were consistent.

[0151] (1) Determination of soil pH, electrical conductivity and water-soluble base ion content

[0152] The air-dried soil samples were ground and crushed, then sieved (2 mm), and soil suspension samples were prepared at a mass ratio of water: soil = 5:1. The soil pH was measured using a BPH-252 pH meter, and the conductivity was measured using a Shanghai Lei magnetic conductivity meter. Each group was repeated three times. For the determination of the water-soluble basic ion content in the soil, the carbonate ion concentration was first determined using a phenolphthalein indicator, and then all carbonates were neutralized into bicarbonates using a standard acid, and then the chloride ion concentration was titrated with a silver nitrate reagent; the sulfate ion used the EDTA volumetric method, first using excess BaCl2 to convert the SO4 2- After the precipitation is complete, EDTA is used for titration with chrome black T as the indicator; Calcium and magnesium are determined by EDTA complexometric titration, as EDTA can form stable complexes with calcium and magnesium ions; Potassium and sodium are determined by flame photometry.

[0153] Variance analysis was performed on the soil water-soluble salt ion content, pH, and conductivity, and the results are shown in Table 7.

[0154] Table 7 Eight major ions, pH and conductivity of soil

[0155]

[0156] Note: The data in Table 7 are the results of testing the soil from the sorghum planting belt, sesbania planting belt and silage corn planting belt respectively.

[0157] As shown in Table 7, planting sorghum and sesbania in strips in the S4C2 planting pattern can significantly reduce the eight major ion contents, pH and electrical conductivity of the soil.

[0158] (2) Determination of soil sucrase activity and carbon composition

[0159] The 3,5-dinitrosalicylic acid colorimetric method was used to determine the activity of soil sucrase, and it was expressed as the milligrams of glucose per gram of soil under the action of sucrase at 37°C for 24 hours [mg / (g·24h)C6H6O6, mg / g]; the sodium phenol colorimetric method was used to determine the activity of soil urease, and it was expressed as the milligrams of NH3-N per gram of soil under the action of urease at 37°C for 48 hours [mg / (g·48h)NH3-N, mg / g]; the potassium permanganate titration method was used to determine the activity of soil catalase, and it was expressed as the volume of 0.1 mol / L KMnO4 consumed by each gram of soil under the action of catalase in 24 hours (mL / g).

[0160] Soil light organic carbon (LFOC) was determined by NaI density separation method (Zhang et al., 2007), soluble organic carbon (DOC) was determined by wet oxidation method, particulate organic carbon (POC) was determined by sodium hexametaphosphate dispersion method (Cambardella et al., 1992), and easily oxidizable carbon (EOC) was determined by potassium permanganate oxidation-colorimetry (Blair et al., 1995). Soil microbial biomass carbon (MBC) and nitrogen (MBN) were determined by chloroform fumigation-K2SO4 extraction method, and soil nitrate nitrogen was determined according to the method of Lu Rukun (2000). Soil particulate organic nitrogen (PON) was determined by 5g / L sodium hexametaphosphate dispersion method, soluble organic nitrogen (DON) was determined by 0.5mol / L potassium sulfate extraction method, and light organic nitrogen (LFON) content was determined by light group separation method (Liu et al., 2015).

[0161] The results of soil sucrase activity and carbon composition determination are shown in Table 8.

[0162] Table 8 Soil enzymes and carbon components

[0163]

[0164] Note: The data in Table 8 are the results of testing the soil from the sorghum planting belt, sesbania planting belt and silage corn planting belt respectively.

[0165] As shown in Table 8, strip planting of sorghum and sesbania can change soil enzyme activity and soil carbon composition in saline-alkali land, and the effect is better than strip planting of sorghum and silage corn.

[0166] (3) Determination of soil bacterial diversity

[0167] Bacterial DNA extraction, amplification, and sequencing: Soil samples were transported on dry ice to Novogene Biotech for sequencing. Weigh 0.5 g of soil and extract genomic DNA using a magnetic bead soil and feces genomic DNA extraction kit. After extraction, 1% agarose gel electrophoresis was used to detect DNA purity and concentration, and the sample was diluted to 1 ng·μL with sterile water. -1 , and 1 μL of the diluted genomic DNA sample was used for amplification with the primer sequence 515F (5'-CCTAYGGGRBGCASCAG-3') for prokaryotic 16S rDNA, and then NovaSeq 6000 was used for PE 250 sequencing; the dada2 method in QIIME22020.6 was used for denoising to obtain the final ASVs (i.e., amplicon sequence variations), and the database was Silva 138.1. The test results are shown in Table 9.

[0168] Table 9 Diversity of soil bacteria

[0169]

[0170] As shown in Table 9, strip planting of sorghum and sesbania can improve the soil Chao1 index and pielou-E index, and can increase the microbial diversity index.

[0171] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for strip planting of sorghum and sesbania in saline-alkali land, characterized in that: The strip planting of sorghum and sesbania was carried out in a strip planting pattern of 4 rows of sorghum + 2 rows of sesbania.

2. The strip planting method of sorghum and sesbania in saline-alkali land according to claim 1, characterized in that: The strip planting of sorghum and sesbania adopts a dry-seeding and wet-out cultivation method with drip irrigation under the film and precision seeding on the film.

3. The strip planting method of sorghum and sesbania in saline-alkali land according to claim 2, characterized in that: The row spacing of the sorghum is 60 cm, and the plant spacing is 15 cm; the row spacing of the sesbania is 60 cm, and the plant spacing is 15 cm; the row spacing between the sorghum and the sesbania is 60 cm.

4. The strip planting method of sorghum and sesbania in saline-alkali land according to claim 2, characterized in that: The sorghum and the sesbania are sown and mowed at the same time; the sowing is carried out in spring or summer.

5. The strip planting method of sorghum and sesbania in saline-alkali land according to claim 4, characterized in that: Apply compound fertilizer 320kg·hm before sowing -2 .

6. The strip planting method of sorghum and sesbania in saline-alkali land according to claim 4, characterized in that: The method further comprises the step of tilling after sowing, wherein the tilling comprises: tilling during the germination stage and the seedling stage of sorghum and sesbania, respectively, with the soil depth being 10-15 cm.

7. The strip planting method of sorghum and sesbania in saline-alkali land according to claim 4, characterized in that: The mowing is carried out twice a year.

8. The strip planting method of sorghum and sesbania in saline-alkali land according to claim 7, characterized in that: After sowing, the method also includes the step of water and fertilizer management, which includes: dripping water 6 times from the sowing day to the heading period before the first mowing, with a total dripping volume of 3525m 3 ·hm -2 , apply top dressing while dripping water; after the first mowing, drip water and apply top dressing fertilizer every 15 to 20 days.

9. The strip planting method of sorghum and sesbania in saline-alkali land according to claim 8, characterized in that: From the sowing date to the heading period before the first mowing, water was dripped 6 times in total, with a total dripping volume of 3525m 3 ·hm -2 , topdressing at the same time as dripping includes: the first dripping on the day after sowing, the dripping volume is 200m 3 ·hm -2 ; The second dripping was carried out on the 4th day after sowing, with a dripping volume of 175m 3 ·hm -2 , drip irrigation 1-2kg / mu wood vinegar; the third drip irrigation is carried out 45-60 days after sowing, with a drip volume of 900m 3 ·hm -2 , urea 150kg·hm -2 and diammonium phosphate 75kg·hm -2 ; The fourth dripping is carried out on the 61st to 70th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ; The fifth dripping is carried out on the 80th to 90th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ; The sixth dripping was carried out on the 91st to 100th day after sowing, with a dripping volume of 750m 3 ·hm -2 , urea 150kg·hm -2 ; And / or, after the first mowing, watering and topdressing every 15 to 20 days includes: each dripping amount is 750m 3 ·hm -2 , urea 225kg·hm -2 .

10. A method for improving saline-alkali land, characterized in that: On saline-alkali land, sorghum and sesbania were planted in strips in a pattern of 4 rows of sorghum + 2 rows of sesbania.

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