Cultivation technical method for relay intercropping of asparagus and green manure in saline-alkali soil

Abstract

The invention particularly relates to a cultivation technical method for relay intercropping of asparagus and green manure in saline-alkali soil. The method comprises the following steps: S1, fertilizing before planting, deeply ploughing, ditching and watering; s2, adopting a nutrition pot to culture seedlings and planting asparagus; s3, green manure sesbania and suaeda glauca are planted between rows, S4, the sesbania and the suaeda glauca are regularly cut in the growth period of the green manure, and S5, suaeda glauca plants are removed after winter, the sesbania is smashed, turned and pressed into soil, and urea and the like are cooperatively applied to promote decomposition; s6, asparagus cultivation management: removing field green manure residues in a harvesting period, performing conventional fertilizer and water management, topdressing high-potassium organic fertilizer in autumn in a root raising period, covering rice husks or straws in winter and the like, and improving the salt resistance and soil environment of the asparagus; and step S7, circularly intercropping for 2-3 years. According to the scheme, biological desalination (suaeda salsa) and nitrogen fixation and land cultivation (sesbania) are cooperated, sustainable improvement of production of the asparagus in the saline-alkali soil is achieved, and green manure benefits in the current year and long-term soil remediation are both considered.

Description

Technical Field

[0001] The present application belongs to the technical field of asparagus cultivation in saline-alkali land, and specifically relates to a cultivation technology method of intercropping asparagus and green manure in saline-alkali land. Background Art

[0002] China's coastal saline-alkali land accounts for 40% of the country's total saline-alkali land area and represents a vital reserve land resource, effectively alleviating land resource constraints and ensuring food security. As a major type of medium- and low-yield farmland globally, saline-alkali land's high salinity, high pH, ​​and poor physical and chemical properties severely restrict crop growth. Asparagus is a perennial vegetable with strong salt and alkali tolerance and high economic value, both as a food and medicinal vegetable. my country leads the world in both asparagus cultivation area and export volume. Asparagus is highly adaptable to mildly to moderately saline-alkali environments. Its roots limit sodium ion absorption through osmotic regulation and accumulate osmoprotectants such as proline to maintain cellular water balance. Asparagus roots reach depths exceeding two meters, allowing for strong water absorption and protecting against surface salt stress. Their low transpiration rate reduces the risk of salt accumulation along the transpiration stream. Developing an asparagus industry in saline-alkali land is crucial for ecological protection, high-quality agricultural development, efficient development and utilization of saline-alkali land, and increased farmer income.

[0003] Although asparagus has a certain degree of salt tolerance, it still faces three core problems when growing it in saline-alkali soil:

[0004] Salt stress inhibits growth: high soil osmotic pressure makes it difficult for roots to absorb water, and ion toxicity (especially Na + accumulation) destroys the stability of cell membranes, reduces photosynthetic efficiency, and causes a decrease in asparagus yield.

[0005] Soil structure degradation: The organic matter content in saline-alkali land is generally low, the aggregate stability is poor, and the water and fertilizer retention capacity is weak, which limits the development of asparagus roots and nutrient absorption.

[0006] Secondary salinization is exacerbated: Although traditional irrigation salt suppression methods (such as freshwater leaching) can reduce salinity in the short term, they consume a lot of water, and as water evaporates, salt accumulates on the surface, requiring periodic repetition of the operation, which is costly.

[0007] Intercropping green manure in saline-alkali land is an ecological improvement technology that combines salt-tolerant green manure crops with main crops. Its core advantage lies in the simultaneous biological desalination, fertilization, and ecological restoration. Chinese Patent Publication No. CN112106601B discloses a method for intercropping green manure in coastal saline-alkali orchards. By combining salt-tolerant annuals with less salt-tolerant perennial green manures in coastal saline-alkali orchards, this method addresses the problems of salt damage and weeds in fruit tree cultivation in saline-alkali land. This method creates a low-salinity environment and provides long-term green manure coverage, reducing weed control costs and promoting the coordinated growth of fruit trees and green manure.

[0008] Therefore, in view of the problems existing in growing asparagus in saline-alkali land in coastal areas, it is urgent to propose a green manure intercropping method that can not only ensure asparagus yield but also reduce salt and fix nitrogen, so as to solve the current problem of growing asparagus in saline-alkali land. Summary of the Invention

[0009] In response to the problems existing in growing asparagus in saline-alkali land in coastal areas, this application proposes a green manure intercropping method that can not only ensure asparagus yield but also reduce salt and fix nitrogen, so as to solve the current difficulties in growing asparagus in saline-alkali land.

[0010] The technical solution of this application is as follows:

[0011] A cultivation method for intercropping asparagus and green manure in saline-alkali soil comprises the following steps:

[0012] Step S1. Preparation before planting

[0013] Spread organic fertilizer, gypsum, and superphosphate on the ground, then deep plow, dig planting trenches, and water;

[0014] Step S2. Asparagus Planting

[0015] Seedlings are grown in nutrient pots, 80-90 days old, and then transplanted and managed;

[0016] Step S3. Green manure planting

[0017] Dig furrows between asparagus rows, sow sesbania and Suaeda salsa, cover with soil, and water;

[0018] Step S4. Green manure field management

[0019] When the height of Sesbania sesbania is greater than 60 cm, mow it for the first time and leave a 30 cm stubble. Then mow it once every 30 to 40 days. There is no need to mow Suaeda salsa.

[0020] Step S5: Green manure turning and nutrient release

[0021] Remove the Suaeda salsa from the asparagus field, then cut the Sesbania sesbania and crush it on the spot, spread urea, and deep-plow the soil to 20-25 cm. Then water it and cover it with plastic film or straw to allow it to decompose.

[0022] Step S6. Asparagus field management

[0023] Harvest period: remove green manure residues, fertilize, water, and till the land regularly;

[0024] Rooting period: In early September in autumn, dig furrows between asparagus rows and apply medium-nitrogen, medium-phosphorus, high-potassium compound fertilizer and decomposed organic fertilizer to promote asparagus growth and enhance its salt resistance. In winter, cover the ridge surface with 5cm of rice husks or chopped straw to inhibit salt and keep warm.

[0025] Preferably, in step S1, the application amount of organic fertilizer is 5-6 cubic meters per mu, the application amount of gypsum is 200-300 kg per mu, and the application amount of superphosphate is 50 kg per mu.

[0026] Preferably, in step S1, deep plowing is performed to 40-50 cm, and planting furrows are opened at a row spacing of 1.2, with a furrow depth of 10-15 cm and a width of 20-30 cm. Water is then irrigated in the furrows at a rate of 80-100 m 3 / mu.

[0027] Preferably, the specific operations of the colonization management in step S2 are:

[0028] Dig planting holes in the planting ditch at a spacing of 25-30 cm. The planting holes are 5-7 cm deep and planted individually. After planting, water the planting ditch at a rate of 50-60 m3 / mu. 90 days after planting, take soil from between the rows and fill the planting ditch.

[0029] At the end of March or the beginning of April of the following year, take soil from between the rows again and add soil to the planting rows to form small raised ridges with a height of 10-20 cm in the asparagus planting rows; apply fertilizer once every 30 days after planting, dig furrows 10-20 cm away from the base of the asparagus stems, with a depth of 10-15 cm, and water once every 15-20 days. After each watering, cultivate and hoe the surface soil, and water each time so that the water infiltration depth is ≥50 cm.

[0030] Preferably, the fertilizer is a medium-nitrogen, low-phosphorus, high-potassium compound fertilizer, with a spreading rate of 20-30 kg / mu.

[0031] Preferably, in step S3, the sowing amount of Sesbania quinata is 5-6 kg / mu, and the sowing amount of Suaeda salsa is 1-1.5 kg / mu.

[0032] Preferably, in step S4, the green manure field management maintains soil moisture at 60% to 70%.

[0033] Preferably, in step S5, the amount of urea applied is 10 kg / mu.

[0034] Preferably, in step S5, 15-20 kg / mu of high-nitrogen, medium-phosphorus, and medium-potassium compound fertilizer is applied every 15-20 days during the harvest period, and the land is watered and tilled after fertilization; the spreading amount of the medium-nitrogen, medium-phosphorus, and high-potassium compound fertilizer applied during the rooting period is 20-30 kg / mu, and the decomposed organic fertilizer is 3-4 cubic meters / mu.

[0035] Preferably, the steps further include:

[0036] Step S7: Cycle the intercropping of asparagus and green manure for 2 to 3 years.

[0037] Beneficial effects of this application:

[0038] This solution achieves sustainable improvement of asparagus production in saline-alkali soils by synergizing biological desalination (Suaeda salsa) with nitrogen fixation (Sebastiana sesbania) to balance current-year green manure benefits and long-term soil remediation. As a pioneer halophyte, Suaeda salsa's roots efficiently accumulate sodium ions and other salts in the cultivated layer. By mowing the entire plant and removing it from the field, salt is permanently removed. Intercropping for two consecutive years can reduce soil salinity. Sesbania sesbania replenishes soil nitrogen nutrients through biological nitrogen fixation. Its fresh biomass, returned to the field after deep plowing, increases soil organic matter content, promotes the formation of aggregate structure, enhances soil water retention and permeability, and alleviates saline-alkali compaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of the planting technology for this application. DETAILED DESCRIPTION

[0040] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0041] The applicant has been engaged in research related to asparagus cultivation in saline-alkali soils and has found that intercropping green manure can solve three core problems in asparagus cultivation in saline-alkali soils: reducing salt, increasing fertilizer, and improving structure.

[0042] First, the green manure must meet the required salt tolerance, otherwise it will not survive. Second, it must match the growth characteristics of asparagus (for example, shallow roots are sensitive to waterlogging). The green manure root system should not be too deep, as this will affect the growth of the asparagus root system. Field operation convenience must also be considered. Finally, the green manure should not compete with the asparagus for water and fertilizer, and it is best to suppress weeds.

[0043] Through preliminary experiments, a large number of salt-tolerant crops were selected: Sesbania sesbania is extremely salt-tolerant (it can grow in a salt content of 0.4%), has good nitrogen fixation, and has a shallow root system that has low competitiveness with asparagus roots; although the Sesbania sesbania plants are tall, the height is controlled by regular harvesting, which does not affect the light exposure of asparagus. As a green manure intercropped with asparagus in saline-alkali soil, Sesbania sesbania has obvious advantages.

[0044] Suaeda salsa is a typical halophyte, whose roots can absorb and enrich salt (especially sodium ions) in the soil and store it in its stems and leaves. By harvesting and removing the Suaeda salsa plants, a large amount of salt can be directly removed from the system, effectively reducing the salinity of the cultivated soil and alleviating salt damage to asparagus. Experimental data shows that it can remove 5%-10% of the salt in the soil. The two companion plants of Sesbania sesbania and Suaeda salsa can also form a three-dimensional shade, reducing salt return caused by water evaporation. Therefore, we try to intercrop with asparagus in order to achieve the goal of achieving the synergy of biological desalination (Suaeda salsa) and nitrogen fixation (Sesbania sesbania) to achieve the goal of sustainable improvement of asparagus production in saline-alkali land.

[0045] Example 1

[0046] This embodiment provides a cultivation method for intercropping asparagus and green manure in saline-alkali soil

[0047] The following steps are involved:

[0048] Step S1. Preparation before planting

[0049] In order to effectively improve the physical and chemical properties of saline-alkali soil and lay the foundation for crop growth, first evenly spread 5-6 cubic meters / mu of fully decomposed organic fertilizer on the ground. Decomposed organic fertilizer can not only safely provide rich organic matter and improve the foundation of soil fertility, but also effectively improve the soil aggregate structure, enhance the ability to retain water and fertilizer, and promote the breeding of beneficial soil microbial communities. At the same time, combine the application of gypsum (CaSO4) 200-300 kg / mu and superphosphate 50 kg / mu. The application of gypsum is intended to utilize its calcium ions (Ca 2+ ) replaces the excess sodium ions (Na + ), effectively reducing soil alkalinity and improving permeability.

[0050] After spreading, immediately plow the entire field to a depth of 40-50 cm. The purpose of deep plowing is to mix the organic fertilizer, gypsum, superphosphate and other amendments and fertilizers spread on the surface layer into the deeper soil as much as possible, breaking up the deep compaction layer, increasing soil porosity and permeability, and facilitating deep rooting of crops.

[0051] Trenching, planting, and salt washing and irrigation: After deep plowing and leveling, dig planting trenches with a row spacing of 1.2 meters. The specifications of the planting trench are 10-15 cm deep and 20-30 cm wide. The trenching operation not only provides an accurate position for subsequent crop planting or sowing, but the furrow and ridge structure it forms is more conducive to field management and drainage. Subsequently, water is poured into the planting trench, and the irrigation volume is controlled at 80-100 cubic meters per mu. This irrigation uses water to "wash away salt and alkali", dissolve and wash away excess soluble salts in the tillage layer, and discharge them with water or press them into the deep soil, thereby reducing the salt concentration in the rhizosphere soil and creating a good low-salt starting environment for the crops to be planted.

[0052] Step S2. Asparagus Planting

[0053] (1) Seedling cultivation:

[0054] In order to ensure the success rate and yield quality of asparagus cultivation in saline-alkali soil, the salt-alkali tolerant and excellent asparagus variety 'Jinglu Lu No. 1' was selected (it should be noted that other salt-tolerant asparagus varieties such as 'Apollo' can also be selected). It has a well-developed root system and strong osmotic regulation ability, and is resistant to higher concentrations of sodium ions (Na + ) and chloride ions (Cl - ) has strong tolerance and can maintain relatively normal physiological metabolism and growth potential under moderate saline-alkali stress.

[0055] Using the nutrient pot seedling method, seedlings are transplanted with the intact nutrient soil, leaving the root system undisturbed. The seedlings are kept between 80 and 90 days old. This 80-90-day growth period (conventional cultivation is 60-70 days) ensures that the aboveground parts of the seedlings can fully photosynthesize, accumulating sufficient carbohydrates and other storage nutrients in the underground fleshy roots. This enhances stress resistance and provides energy reserves for rapid growth recovery after planting in saline-alkali soil, ensuring high yields the following year.

[0056] (2) Planting and post-planting management

[0057] Planting Time: Choosing May to July for planting takes advantage of the relatively warm and stable climate (avoiding the threat of late frosts in early spring or low temperatures in autumn) and the long growing season (allowing for harvest the following year). This helps the asparagus seedlings fully utilize light and heat resources, accelerate root recovery and plant growth, accumulate sufficient nutrients for a safe winter, and lay a solid foundation for the first harvest the following spring.

[0058] Planting Procedure and Specifications: Dig 5-7cm deep planting holes in the pre-prepared planting trench, with a spacing of 25-30cm between plants. Use a single-plant planting method, planting only one asparagus seedling in each hole. This 25-30cm spacing ensures that each asparagus plant has balanced space and nutrient competition during future growth, avoiding overcrowding that can lead to poor ventilation and light transmission and increased vulnerability to pests and diseases.

[0059] Watering after planting: Water the planting ditch immediately after planting, and control the irrigation volume at 50-60 cubic meters per mu.

[0060] Fill the planting trench: 90 days after planting, remove soil from between the rows and fill the original planting trench. This leveling will make the original planting row level with or slightly lower than the row, which helps evenly distribute moisture from winter rain and snow across the field and reduces direct impact of cold winds on the root canopy.

[0061] Ridge Building in the Spring of the Following Year: In the spring of the second year (late March to early April), soil is again collected from between the rows and added to the planting rows (i.e., the original planting trenches, now filled). This buildup creates small raised ridges 10-20 cm high around the asparagus rows. These ridges cover the bases of the emerging asparagus stems, providing them with a certain amount of soil pressure as they sprout, resulting in a high-quality product. The 10-20 cm ridge height also prevents the mother stems from falling over during the stem retention period and provides space for subsequent green manure cultivation.

[0062] Fertilization management in the year of asparagus planting: Fertilize once every 30 days after planting. Dig a trench 10-20 cm away from the base of the asparagus stem (the trench depth is 10-15 cm). Apply medium-nitrogen, low-phosphorus, and high-potassium compound fertilizer at a dosage of 20-30 kg / mu. Fertilization by trenching ensures that the fertilizer is concentrated near the main distribution layer of the root system, reducing nutrient volatilization and loss, and improving fertilizer utilization. Dig a trench 10-20 cm away from the base of the stem to avoid direct contact with the root system and cause fertilizer damage. "Medium nitrogen" meets the needs of steady growth of stems and leaves; "low phosphorus" is because the effective phosphorus in saline-alkali soil is easily fixed, and excessive phosphorus application has poor effects and may aggravate the salt problem; "high potassium" is based on the fertilizer requirements of asparagus, and is crucial to enhancing the stress resistance of asparagus plants, promoting the transportation and storage of assimilated products to the fleshy roots, and improving the quality of tender stems.

[0063] Watering and Tillage: Water every 15-20 days. Each watering must ensure that water infiltration reaches a depth of 50 cm or more. Surface soil should be tilled and plowed promptly after each watering. The fundamental purpose of requiring water infiltration to a depth of 50 cm or more is to achieve "periodic salt removal and compression." Each irrigation dissolves soluble salts accumulated in the root zone and washes them deeper. Tillage and plowing effectively disrupt the capillary structure of the soil surface, preventing deep-seated water from carrying salt to the surface and evaporating and accumulating.

[0064] Step S3. Green manure planting

[0065] Plant green manure between asparagus rows. A combination of Sesbania truncatula (a nitrogen-fixing powerhouse) and Suaeda salsa (a bio-desalination pioneer) is used to achieve both nitrogen fixation and desalination. Planting should be done in the spring of the second year after planting.

[0066] (1) Mixed sowing of Sesbania truncatula and Suaeda salsa

[0067] Variety selection principles: To ensure that mixed seeding combinations grow effectively and function as expected in saline-alkali environments, it is essential to strictly select proven, adaptable, salt-tolerant varieties. Selected Sesbania and Suaeda varieties must demonstrate good germination, emergence, and sustained growth in saline-alkali soils.

[0068] Sowing Time: Late May to early June. Planting during this time takes advantage of the gradually rising temperatures and relatively abundant sunlight of early summer. This promotes rapid seed germination and early seedling growth. It also ensures that green manure quickly covers the ground during the asparagus's peak growing season and coordinates with the asparagus's water and fertilizer management cycles.

[0069] Sowing Location and Method: Dig shallow trenches 2-3 cm deep between asparagus rows, with row spacing of 30-40 cm, and broadcast sowing. Leaving space between asparagus rows avoids direct competition with asparagus plants and fully utilizes idle land resources. Sowing in shallow trenches 2-3 cm deep ensures smooth emergence of both green manure seeds. Setting row spacing of 30-40 cm provides adequate growth space for both green manure plants, facilitates ventilation and light, and facilitates subsequent field management.

[0070] Seeding rate: 5-6 kg / mu for Sesbania; 1-1.5 kg / mu for Suaeda. The higher seeding rate for Sesbania is intended to ensure rapid biomass formation and shading, while the relatively lower seeding rate for Suaeda takes into account its strong natural diffusion ability and large crown width per plant, avoiding overcrowding later in the seeding process. After sowing, lightly rake the soil to a depth of 1 cm to provide the necessary cover for the seeds, which facilitates water absorption and maintains the microenvironmental humidity required for germination without hindering seedling emergence. After sowing, water thoroughly to fully moisten the seedbed and provide an adequate and continuous water supply for seed swelling and germination. In saline-alkali soil, sufficient water can help temporarily reduce the salt concentration in the soil solution around the seeds, creating a relatively favorable initial germination microenvironment.

[0071] Advantages of mixed broadcast:

[0072] First, Sesbania provides shade for Suaeda salsa, inhibiting salinization. Sesbania is characterized by rapid growth, tall plants, and lush foliage. When mixed, Sesbania quickly forms an effective shade cover over the ground, reducing excessive surface water evaporation caused by direct sunlight. By inhibiting evaporation, the migration and accumulation of deep soil moisture (carrying dissolved salts) to the surface through capillary action (a process known as "salinization") is effectively reduced.

[0073] Second: Suaeda improves the rhizosphere environment for Sesbania sesbania and reduces salt stress. Suaeda is a typical halophyte that can actively absorb and accumulate excess sodium ions (Na + ) and other salt ions into the body or specific parts. Through biological salt absorption, Suaeda salsa effectively reduces the salt concentration (especially Na) in the soil solution around its rhizosphere. + concentration).

[0074] The shade provided by Sesbania salsa suppresses salt production, while the biological absorption of salt by the plant reduces the burden on the Sesbania salsa root system and increases its efficiency. This synergistic effect improves the overall adaptability and effectiveness of the mixed-cropping system on saline-alkali soils, contributing to soil improvement between asparagus rows (reducing salt damage, increasing cover, improving soil structure, and enhancing fertility).

[0075] Step S4. Green manure field management

[0076] (1) Water management (core of salt control)

[0077] Core requirements: Keep soil moisture stable in the range of 60% to 70% (manifested by slightly moist topsoil without cracking). In saline-alkali land environments, by maintaining the soil solution in the root zone in a relatively "diluted" state (high water content), the salt ions (Na + , Cl - The concentration of water (such as iodine, iodine, etc.) can be directly reduced to reduce the osmotic stress and ion toxicity suffered by the crop roots.

[0078] (2) Green manure height control

[0079] Sesbania management (periodic mowing): Mow the first time when the plant height is ≥60 cm, leaving a stubble height of 30 cm. Mow every 30-40 days thereafter. Timely mowing prevents the sesbania from growing too tall and falling over, which can affect growth and field operations. It also prevents excessive shading, which can affect the photosynthesis of the asparagus.

[0080] Suaeda Management: Suaeda is allowed to grow naturally (typical plant height is 30-50 cm) and does not require mowing. However, any plants that invade the asparagus root zone should be removed manually. Allowing Suaeda to grow naturally allows it to fully utilize its halophyte properties, effectively reducing soil salinity near the roots. Mowing is unnecessary because Suaeda typically grows relatively low and densely, which is less likely to overly shade the asparagus. Furthermore, its natural growth pattern contributes to ground cover and salt suppression.

[0081] Step S5: Green manure turning and nutrient release

[0082] 1. Timing of turning over

[0083] The best time is 7 to 10 days before the first frost (around late October). At this time, after vigorous growth and multiple regeneration throughout the growing season (especially in summer), the accumulation of aboveground biomass of Sesbania has reached its peak (fresh weight can reach 3 to 5 tons / mu), and after turning over, it can provide the soil with the maximum amount of organic matter.

[0084] By turning over the asparagus after its above-ground growth has essentially ceased, the long decomposition process after turning over is offset from the asparagus growing season. This avoids the risk of vigorous decomposition microorganisms competing with the asparagus for soil nutrients and oxygen, ensuring nutrient accumulation in the asparagus storage roots and smooth germination and initial growth of the tender shoots the following spring.

[0085] 2. Turning and pressing operation

[0086] (1) Cutting and crushing: First, manually pull out all the Suaeda salsa plants and move them out of the asparagus field. After that, the Sesbania sesbania is cut mechanically or manually and crushed into 5-10 cm long fragments on site. Since the Suaeda salsa plants are rich in salts absorbed from the soil, if they are turned over and returned to the field, these salts will be released back into the soil during the decomposition process, completely offsetting the biological salt absorption benefits of the plants during the growing season, and may even lead to an increase in local salt concentrations. Therefore, they must be removed from the field to achieve permanent removal of salts.

[0087] (2) Broadcasting urea: After deep plowing, evenly spread 10kg of urea per mu. Broadcasting urea is a fast-acting nitrogen fertilizer that can quickly replenish the available nitrogen content in the soil. The added fast-acting nitrogen stimulates the number and activity of microbial populations, thereby accelerating the decomposition of the sesbania green manure.

[0088] (3) Deep plowing: After evenly spreading the crushed sesbania segments on the field surface, deep plowing is performed to bury the green manure material into the soil to a depth of 20-25 cm. Deep plowing to 20-25 cm means burying the green manure material above the main fleshy absorbing roots of the asparagus. This allows the green manure to decompose above the main root zone of the asparagus, gradually releasing nutrients for the root system to absorb and utilize, while also avoiding the negative impact that may be caused by a large amount of undecomposed organic matter directly contacting the root system.

[0089] 3. Management during the decomposition period

[0090] After spreading urea and turning it over, water it thoroughly. Then, cover the ground with film or evenly spread a layer of straw (about 5-10 cm thick).

[0091] Mulch effectively reduces heat loss from the soil, maintains a relatively high ground temperature, overcomes the inhibitory effects of low temperatures on microbial activity, and improves decomposition efficiency in winter and early spring. Mulch effectively reduces evaporation of soil moisture, maintains an appropriate humidity level in the compost layer, and ensures the moisture conditions necessary for sustained microbial activity.

[0092] It is prohibited to carry out any turning operations in the spring of the following year (especially during the germination and harvesting period of asparagus stems)!

[0093] During the mid-decomposition phase of green manure, microorganisms need to assimilate large quantities of available nitrogen in the soil to break down carbon, temporarily reducing the available nitrogen available to plants. If the green manure is turned over in the following spring, the newly added, undecomposed green manure will immediately trigger intense microbial nitrogen fixation, competing with the asparagus stems for valuable, fast-acting nitrogen. This nitrogen deficiency can lead to stunted growth, weak stems, and a significant decline in yield and quality.

[0094] Step S6. Asparagus field management

[0095] Harvest period (March-June): Remove green manure residue and keep the ridge surface bare (to reduce the accumulation of salt in the asparagus root zone). Every 15-20 days, apply 15-20 kg / mu of high-nitrogen, medium-phosphorus, and medium-potassium compound fertilizer. After fertilization, water promptly and till the land.

[0096] Autumn rooting period (early September): dig furrows between asparagus rows and apply 20-30 kg / mu of medium-nitrogen, medium-phosphorus, and high-potassium compound fertilizer and 3-4 cubic meters / mu of decomposed organic fertilizer to promote asparagus growth and enhance its salt resistance.

[0097] Winter (December-February): Cover the ridges with a 5cm thick layer of rice husks or chopped straw to reduce salt and retain heat. Although evaporation is relatively low in winter, persistent winds and low, dry temperatures can still cause a slow evaporation of soil moisture. Mulching effectively blocks soil capillaries, reducing evaporation and thus preventing deep-seated salt from migrating and accumulating on the ridge surface with evaporating water. The mulch creates a physical barrier, reducing heat loss from the soil and buffering against low-temperature fluctuations.

[0098] Step S7. After two consecutive years of intercropping, the soil salt content decreased by 32.6%-48.1%, the organic matter content increased by 34.1%-48.5%, and the tender stem yield in the spring of the third year increased by 15.3%-19.20% (salt stress relief + nutrient supply enhancement). The specific measurement results are shown in Tables 1 and 2.

[0099] Table 1 Soil salt content and organic matter determination

[0100]

[0101] Note: Asparagus will be planted in 2021 and green manure will be planted in 2022

[0102] Table 2 Asparagus yield determination

[0103]

[0104]

[0105] Note: Asparagus was planted in 2021, and intercropping with green manure started in 2022. The yield is the yield in 2024.

[0106] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A cultivation method for intercropping asparagus and green manure in saline-alkali soil, characterized in that: The steps include: Step S1. Preparation before planting Spread organic fertilizer, gypsum, and superphosphate on the ground, then deep plow, dig planting trenches, and water; Step S2. Asparagus Planting Seedlings are grown in nutrient pots, 80-90 days old, and then transplanted and managed; Step S3. Green manure planting Dig furrows between asparagus rows, sow sesbania and Suaeda seeds, cover with soil, and water; Step S4. Green manure field management When Sesbania sesbania plant height exceeds 60cm, mow it for the first time and leave 30cm stubble. Then mow it every 30-40 days. Suaeda salsa does not need to be mowed. Step S5: Green manure turning and nutrient release Remove the Suaeda salsa from the asparagus field, then cut and crush the Sesbania sesbania on the spot, spread urea, and deep-plow the soil 20-25 cm, then water and cover with plastic film or straw for decomposition; Step S6. Asparagus field management Harvest period: remove green manure residues, fertilize, water, and till the land regularly; Rooting period: In early September in autumn, dig furrows between asparagus rows and apply medium-nitrogen, medium-phosphorus, high-potassium compound fertilizer and decomposed organic fertilizer to promote asparagus growth and enhance its salt resistance. In winter, cover the ridge surface with 5cm of rice husks or chopped straw to inhibit salt and keep warm.

2. The cultivation method of a saline-alkali soil asparagus and green manure intercropping method according to claim 1, characterized in that: In step S1, the spreading amount of organic fertilizer is 5-6 cubic meters per mu, the spreading amount of gypsum is 200-300 kg per mu, and the spreading amount of superphosphate is 50 kg per mu.

3. The cultivation method of a saline-alkali soil asparagus and green manure intercropping method according to claim 1, characterized in that: In step S1, deep plowing is carried out to 40-50 cm, and planting furrows are opened at a row spacing of 1.2, with a furrow depth of 10-15 cm and a width of 20-30 cm. Water is then irrigated in the furrows at a rate of 80-100 m 3 / mu.

4. The cultivation method of a saline-alkali soil asparagus and green manure intercropping method according to claim 1, characterized in that: The specific operations of the colonization management in step S2 are: Dig planting holes in the planting ditch at a spacing of 25-30 cm. The planting holes are 5-7 cm deep and planted individually. After planting, water the planting ditch at a rate of 50-60 m3 / mu. 90 days after planting, take soil from between the rows and fill the planting ditch. At the end of March or the beginning of April of the following year, take soil from between the rows again and add soil to the planting rows to form small raised ridges with a height of 10-20 cm in the asparagus planting rows; apply fertilizer once every 30 days after planting, dig furrows 10-20 cm away from the base of the asparagus stems, with a depth of 10-15 cm, and water once every 15-20 days. After each watering, cultivate and hoe the surface soil, and water each time so that the water infiltration depth is ≥50 cm.

5. The cultivation method of intercropping asparagus and green manure in saline-alkali soil according to claim 4, characterized in that: The fertilizer used is a medium-nitrogen, low-phosphorus, high-potassium compound fertilizer, and the application rate is 20-30kg / mu.

6. The cultivation method of intercropping asparagus and green manure in saline-alkali soil according to claim 1, characterized in that: In step S3, the sowing amount of Sesbania quinata is 5-6 kg / mu, and the sowing amount of Suaeda salsa is 1-1.5 kg / mu.

7. The cultivation method of intercropping asparagus and green manure in saline-alkali soil according to claim 1, characterized in that: In step S4, the green manure field management maintains the soil moisture at 60% to 70%.

8. The cultivation method of intercropping asparagus and green manure in saline-alkali soil according to claim 1, characterized in that: In step S5, the amount of urea applied is 10 kg / mu.

9. The cultivation method of intercropping asparagus and green manure in saline-alkali soil according to claim 1, characterized in that: In step S6, 15-20 kg / mu of high-nitrogen, medium-phosphorus, and medium-potassium compound fertilizer is applied every 15-20 days during the harvest period, and the land is watered and tilled after fertilization; the spreading amount of the medium-nitrogen, medium-phosphorus, and high-potassium compound fertilizer applied during the rooting period is 20-30 kg / mu, and the decomposed organic fertilizer is 3-4 cubic meters / mu.

10. The cultivation method of intercropping asparagus and green manure in saline-alkali soil according to claim 1, characterized in that: The steps also include: Step S7: Cycle the intercropping of asparagus and green manure for 2 to 3 years.

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