Process for planting tilia miqueliana in coastal salt-tolerant land

Abstract

The invention relates to the technical field of planting in salt-tolerant land, in particular to a process for planting tilia miqueliana in coastal salt-tolerant land, which comprises the following steps: (1) pretreatment of planting land; (2) seed pretreatment; (3) sowing and seedling cultivation; (4) field planting and later maintenance; all links of the whole process cooperate with one another, and efficient and high-quality planting of tilia miqueliana in the coastal salt-tolerant land is achieved. A good soil foundation is provided for seed germination and seedling growth due to the salt isolation and fertility improvement effects of the layered improved structure; seed pretreatment endows the seedlings with innate salt resistance, so that the seedlings can quickly adapt to a saline-alkaline environment; the later-stage maintenance measures continuously guarantee environment stability and nutrient supply in the plant growth process, all links are linked with one another and have a synergistic effect, the survival rate of tilia miqueliana is increased, vegetation recovery and utilization of the coastal salt-tolerant land are achieved, the ecological environment is protected, and remarkable economic value and ecological benefits are achieved.

Description

Technical Field

[0001] This invention relates to the field of salt-tolerant land cultivation technology, specifically a process for cultivating Nanjing linden in coastal salt-tolerant land. Background Technology

[0002] Nanjing linden, a precious native tree species in my country, possesses ecological, ornamental, and economic value. Its beautiful tree shape and strong resilience make it a promising candidate for urban greening and ecological restoration. However, many coastal areas of my country have saline-tolerant soils, which generally suffer from high salt content, low fertility, soil compaction, and poor drainage, severely hindering normal plant growth. While Nanjing linden exhibits some resilience, excessive salt in high-salt environments can lead to difficulties in root water absorption and disrupted physiological metabolism. Furthermore, high salt stress inhibits soil microbial activity and reduces nutrient availability, resulting in low seed germination rates, poor seedling survival rates, slow growth, and even death. This makes large-scale cultivation of Nanjing linden in saline-tolerant coastal areas difficult.

[0003] Currently, some research has been conducted on the improvement and planting techniques for saline-tolerant coastal land, with common methods including the application of chemical amendments or the use of conventional seedling cultivation methods. However, these existing technologies have many shortcomings: although chemical amendments can reduce soil salinity in the short term, long-term use can easily cause secondary soil pollution and cannot continuously improve soil fertility; conventional seedling cultivation does not conduct salt-tolerant pretreatment based on the growth characteristics of Nanjing linden, resulting in weak salt resistance in seedlings, coupled with a lack of systematic post-cultivation care measures, leading to a low planting success rate.

[0004] With the increasing demand for ecological construction, higher requirements are being placed on the restoration and utilization of vegetation in coastal saline-tolerant areas. Developing a planting technology that can balance soil salinity regulation, fertility enhancement, and the growth needs of Nanjing linden, and solving problems such as incomplete salt barrier, poor soil improvement effect, and insufficient salt tolerance of plants in existing technologies, to achieve efficient planting of Nanjing linden in coastal saline-tolerant areas, has become an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and propose a process for planting Nanjing linden in salt-tolerant coastal areas.

[0006] The specific technical solution is as follows: A process for planting Nanjing linden in saline-tolerant coastal areas includes the following steps: (1) Pretreatment of planting land: Deep plowing and leveling of coastal salt-tolerant land, dividing planting areas, and constructing drainage ditches; laying a layered improvement structure in the planting area, the layered improvement structure being, from bottom to top, a salt isolation layer, a soil improvement layer, and a surface covering layer; The salt isolation layer contains 0.5-0.9% nano zinc oxide particles by total mass, the nano zinc oxide particles having a particle size of 60-90 nm, which are then laid out after being mixed with other components of the salt isolation layer by high-speed stirring. The salt-tolerant bacterial agent added to the soil amendment layer contains 0.35-0.45% of a bacterial agent protectant, which is a chitosan-sodium alginate composite microsphere with a particle size of 1.5-2.5 μm, prepared by emulsification crosslinking method; (2) Seed pretreatment: Select plump Nanjing linden seeds and perform dormancy breaking treatment and salt tolerance induction treatment in sequence to obtain salt tolerance pretreated seeds; (3) Sowing and seedling cultivation: Sow salt-tolerant pretreated seeds into the surface covering layer of the layered improved structure, control the sowing density and temperature and humidity, and cultivate the seedlings until the seedlings are 15-25cm tall to obtain robust seedlings; (4) Planting and post-planting care: Plant healthy seedlings in the planting area, and after planting, irrigate with salt-tolerant nutrient solution to help them establish roots. Regularly manage water and fertilizer, prevent and control diseases and monitor salt content until the seedlings grow into mature plants.

[0007] As a further technical solution, in step (1), the deep tillage depth is 38-45cm, the planting area is divided according to the row spacing of 2.8-3.2m and the plant spacing of 2.0-2.8m; the drainage ditch spacing is 8.5-9.5m and the depth is 65-75cm, and the ditch is filled with gravel and non-woven fabric; the speed of the high-speed stirring is 1300-1400r / min and the stirring time is 15-18min.

[0008] As a further technical solution, the salt isolation layer has a thickness of 16-20cm and is made by mixing crushed brick slag, coarse sea sand, modified zeolite and nano zinc oxide particles in a mass ratio of 5:3:2:0.07; the modified zeolite is activated at a high temperature of 580-625℃ for 2.0-2.5h, and then pulverized to a particle size of 2.5-4.5mm after cooling.

[0009] As a further technical solution, the soil amendment layer has a thickness of 25-28 cm and is prepared by mixing garden soil, well-rotted green manure, modified composite salt-tolerant matrix, and salt-tolerant bacterial agent in a mass ratio of 4:3:2:0.5; the salt-tolerant bacterial agent is a compound bacterial agent of Bacillus subtilis and humic acid bacteria in a mass ratio of 2:1, with a viable count ≥2.5×10⁻⁶. 9 cfu / g; The parameters for preparing chitosan-sodium alginate composite microspheres by the emulsification crosslinking method are as follows: calcium chloride is used as the crosslinking agent, the crosslinking temperature is 26-30℃, the crosslinking time is 2-2.5h, and the mass ratio of chitosan to sodium alginate is 1:1.5.

[0010] As a further technical solution, the preparation steps of the modified composite salt-resistant matrix include: (1) Raw material pretreatment: Humus, bentonite, potassium feldspar and brown algae extract were crushed to a particle size of 0.15-0.25 mm respectively; (2) Modification treatment: Mix humus and bentonite at a mass ratio of 3:1, add 12-14% of the total mass of 6-7wt% citric acid solution, modify at a constant temperature of 31-36℃ for 26-34h, and dry until the moisture content is ≤8% to obtain modified humus matrix. (3) Composite preparation: The modified humic matrix is ​​mixed with potassium feldspar and brown algae extract at a mass ratio of 8:1.5:0.5 and aged at a constant temperature of 41-44℃ for 16-22h to obtain the modified composite salt-resistant matrix.

[0011] As a further technical solution, the surface covering layer has a thickness of 6-7cm and is made by mixing decomposed straw and coconut coir in a mass ratio of 3:2 and crushing it to a particle size of 1.5-2.5mm.

[0012] As a further technical solution, in step (2), the dormancy breaking treatment is as follows: soak the seeds in warm water at 41-44℃ for 24 hours, mix them with wet sand at a mass ratio of 1:3, and perform low-temperature stratification treatment at 6-12℃ for 32-38 days, while maintaining the moisture content of the sand bed at 42-48%; in the salt tolerance induction treatment, the amount of salt tolerance induction solution used is 600-700mL of induction solution per 100g of seeds.

[0013] As a further technical solution, in step (2), the salt tolerance induction treatment is as follows: the seeds after dormancy is broken are soaked in a salt tolerance induction solution at room temperature for 13-17 hours. The salt tolerance induction solution is a mixture of 0.9-1.1 g / L proline solution and 0.6-0.7 g / L salicylic acid solution in a volume ratio of 1:1.

[0014] As a further technical solution, in step (3), the sowing depth is 2.1-2.8cm, the sowing density is 15-20 seeds per square meter, the cultivation temperature is controlled at 21-24℃, the light duration is 8.5-9.5h / day, and a 1:500 diluted salt-tolerant bacterial agent is sprayed every 8-9 days.

[0015] As a further technical solution, in step (4), the root-fixing salt-tolerant nutrient solution is prepared by mixing 1.1-1.4 g / L potassium dihydrogen phosphate, 0.35-0.45 g / L borax and 0.25-0.35 g / L brown algae extract, and the pH is adjusted to 6.2-6.8. 2.2-2.8L is applied to each plant. The salt content is monitored once a month. When the soil salt content exceeds 0.3%, the drainage ditch is opened to drain the water. At the same time, a 2.0-2.8% citric acid solution is sprayed once every 10 days until the soil salt content drops below 0.3%.

[0016] Compared with the prior art, the present invention has the following beneficial effects: Firstly, the layered improvement structure constructed in the pretreatment stage of the planting site fundamentally solves the problems of salt damage and insufficient fertility in coastal saline-tolerant land. The salt isolation layer uses crushed brick debris and coarse sea sand as its framework, combined with modified zeolite activated at high temperature. The activated modified zeolite has an increased specific surface area and enhanced adsorption capacity, effectively adsorbing salt ions in the soil. The addition of nano zinc oxide particles further enhances the salt adsorption effect through ion exchange, and its antibacterial properties inhibit the reproduction of harmful microorganisms in the soil, reducing the risk of disease. After being mixed evenly with other components at high speed, the two form a stable and well-ventilated isolation barrier, preventing the upward migration of salt from deep soil layers, thus creating a low-salt environment for the growth of Nanjing linden roots. In the soil amendment layer, garden soil and decomposed green manure provide basic nutrients. After being modified with citric acid, the water and fertilizer retention capacity of the modified composite salt-tolerant matrix is ​​significantly improved. Furthermore, the combined effect of potassium feldspar and brown algae extract can supplement plants with mineral elements and bioactive substances. In the salt-tolerant bacterial agent, Bacillus subtilis and humic acid bacteria work synergistically to not only activate fixed nitrogen, phosphorus, and potassium nutrients in the soil, but also decompose organic matter to release nutrients. The bacterial agent protectant made of chitosan-sodium alginate composite microspheres can provide shelter for the bacterial agent in a high-salt environment, improve the survival rate of the bacterial agent, and ensure that it can continue to play a role in improving soil fertility. This solves the problem of poor soil and low nutrient availability in coastal salt-tolerant areas.

[0017] Secondly, the combination of seed pretreatment and subsequent maintenance significantly improved the salt tolerance and growth stability of Nanjing linden. The dormancy-breaking treatment, through warm water soaking and low-temperature stratification, broke the seed dormancy state, improving germination rate and uniformity, laying the foundation for subsequent seedling growth. The combined effect of proline and salicylic acid in the salt tolerance induction solution induced the synthesis of stress-resistant substances in the seeds, enhancing the osmotic pressure regulation capacity of seedling cells, enabling them to absorb water and metabolize normally in low-salt environments, thereby improving the seedlings' adaptability to saline-alkali soils. The post-planting root-setting salt tolerance nutrient solution specifically supplemented key nutrients such as phosphorus, potassium, and boron, promoting rapid root development and enhancing plant stress resistance.

[0018] Finally, the coordinated efforts of all stages of the process enabled the efficient and high-quality cultivation of Nanjing linden in saline-tolerant coastal areas. The layered improvement structure's salt isolation and fertility enhancement provided a favorable soil foundation for seed germination and seedling growth; seed pretreatment endowed seedlings with innate salt tolerance, enabling them to quickly adapt to saline-alkali environments; and subsequent maintenance measures continuously ensured environmental stability and nutrient supply during plant growth. These interconnected and synergistic effects of each stage increased the survival rate of Nanjing linden, achieving vegetation restoration and utilization in saline-tolerant coastal areas, protecting the ecological environment, and demonstrating significant economic and ecological benefits. Attached Figure Description

[0019] Figure 1 This is a flowchart of a process for cultivating Nanjing linden in salt-tolerant coastal areas. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention provides a process for planting Nanjing linden in saline-tolerant coastal areas, comprising the following steps: (1) Pretreatment of planting site: Deep plowing and leveling of coastal salt-tolerant land, dividing planting areas and constructing drainage ditches; laying a layered improvement structure in the planting area, the layered improvement structure from bottom to top being a salt isolation layer, a soil improvement layer and a surface covering layer; adding 0.5-0.9% nano zinc oxide particles by total mass to the salt isolation layer, the nano zinc oxide particles having a particle size of 60-90nm, and laying it after high-speed stirring and mixing with other components of the salt isolation layer; the salt-tolerant bacterial agent added to the soil improvement layer contains 0.35-0.45% bacterial agent protectant, the bacterial agent protectant being chitosan-sodium alginate composite microspheres with a particle size of 1.5-2.5μm, prepared by emulsification cross-linking method; (2) Seed pretreatment: Select plump Nanjing linden seeds and perform dormancy breaking treatment and salt tolerance induction treatment in sequence to obtain salt tolerance pretreated seeds; (3) Sowing and seedling cultivation: Sow salt-tolerant pretreated seeds into the surface covering layer of the layered improved structure, control the sowing density and temperature and humidity, and cultivate the seedlings until the seedlings are 15-25cm tall to obtain robust seedlings; (4) Planting and post-planting care: Plant healthy seedlings in the planting area, and after planting, irrigate with salt-tolerant nutrient solution to help them establish roots. Regularly manage water and fertilizer, prevent and control diseases and monitor salt content until the seedlings grow into mature plants.

[0022] In this invention, step (1) of planting site pretreatment is a fundamental step. Deep tillage can break up the soil compaction layer, improve soil aeration and water permeability, and create favorable conditions for the growth of Nanjing linden roots. The preferred deep tillage depth is 38-45cm, which ensures that the roots can fully extend while avoiding excessive tillage that could damage the soil structure. The division of planting areas should take into account both plant growth space and the convenience of field management. Dividing the area by row spacing of 2.8-3.2m and plant spacing of 2.0-2.8m can ensure that the plants receive sufficient light, nutrients and ventilation during their growth.

[0023] The construction of underground drainage ditches is one of the key measures for planting in saline-tolerant coastal areas. It can promptly remove excess water from the soil, lower the groundwater level, and reduce the accumulation of salt in the surface soil as water rises. The optimal spacing between drainage ditches is 8.5-9.5m, and the depth is 65-75cm. These parameters ensure effective drainage, avoiding both overly dense ditches that increase construction costs and overly sparse ditches that affect drainage efficiency. The ditches are filled with gravel and non-woven fabric. The gravel enhances the drainage capacity and structural stability of the ditches, while the non-woven fabric prevents soil particles from clogging the gaps between the gravel, ensuring smooth drainage.

[0024] The layered improvement structure consists of a salt isolation layer, a soil amendment layer, and a top dressing layer, from bottom to top. These layers work synergistically to regulate soil salinity and enhance fertility. The salt isolation layer, preferably 16-20 cm thick, is made from a mixture of crushed brick fragments, coarse sea sand, modified zeolite, and nano-zinc oxide particles in a mass ratio of 5:3:2:0.07. The crushed brick fragments and coarse sea sand are hard and can create a stable porous structure, improving interlayer air and water permeability. The modified zeolite has excellent adsorption properties, adsorbing salt ions from the soil and reducing soil salinity. It is activated at 580-625℃ for 2.0-2.5 hours, then cooled and pulverized to a particle size of 2.5-4.5 mm. High-temperature activation enhances the adsorption activity and specific surface area of ​​the zeolite, improving the adsorption effect. The nano zinc oxide particles, with a particle size of 60-90 nm, are added at a total mass of 0.5-0.9%. They have good antibacterial and ion exchange capabilities, which can inhibit the reproduction of harmful microorganisms in the soil and participate in the exchange and adsorption of soil salt ions, further reducing the harm of salt. The nano zinc oxide particles are mixed with other components of the salt isolation layer at a high speed and then laid out. The preferred speed of the high-speed mixing is 1300-1400 r / min, and the mixing time is 15-18 min to ensure that all components are mixed evenly and to give full play to their synergistic effect.

[0025] The soil amendment layer is preferably 25-28 cm thick and is made by mixing garden soil, well-rotted green manure, modified composite salt-tolerant matrix, and salt-tolerant microbial agent in a mass ratio of 4:3:2:0.5. Garden soil serves as the base matrix, providing basic nutrients and physical support; well-rotted green manure is rich in organic matter and nutrients such as nitrogen, phosphorus, and potassium, which can improve soil fertility and structure and promote microbial activity; the modified composite salt-tolerant matrix can enhance the soil's water and fertilizer retention capacity and salt tolerance. Its preparation steps include raw material pretreatment, modification treatment, and composite preparation. In the raw material pretreatment, humus, bentonite, potassium feldspar, and brown algae extract are pulverized to a particle size of 0.15-0.25 mm to ensure uniform particle size and facilitate subsequent mixing and reaction. In the modification treatment, humus and bentonite are mixed at a mass ratio of 3:1, and 12-14% of a 6-7 wt% citric acid solution is added. The mixture is then modified at a constant temperature of 31-36℃ for 26-34 hours and dried until the moisture content is ≤8% to obtain a modified humus matrix. The citric acid solution can adjust the soil pH, activate the effective components in humus and bentonite, and improve their adsorption performance and fertilizer retention capacity. In the composite preparation, the modified humus matrix is ​​mixed with potassium feldspar and brown algae extract at a mass ratio of 8:1.5:0.5 and aged at a constant temperature of 41-44℃ for 16-22 hours. Potassium feldspar provides potassium, and brown algae extract is rich in bioactive substances, which can promote plant growth and enhance stress resistance. The constant temperature aging allows the components to fully integrate and optimize the matrix performance.

[0026] The salt-tolerant bacterial agent is a compound bacterial agent of Bacillus subtilis and humic acid bacteria, with a mass ratio of 2:1, and a viable count ≥2.5×10⁻⁶. 9 The cfu / g concentration can be any commercially available one; there are no special requirements. Bacillus subtilis has nitrogen-fixing, phosphorus-solubilizing, and potassium-solubilizing effects, which can activate soil nutrients and inhibit the growth of harmful bacteria. Humic acid bacteria can decompose soil organic matter, release nutrients, and improve soil structure. The combined use of the two can synergistically enhance soil fertility and plant resistance. The salt-tolerant bacterial agent contains 0.35-0.45% of a bacterial agent protectant, which is a chitosan-sodium alginate composite microsphere with a particle size of 1.5-2.5 μm, prepared by emulsification cross-linking. This protectant provides a suitable survival environment for the bacterial agent, protecting it from adverse factors such as salinity and pH in the soil, thereby improving the survival rate and efficacy of the bacterial agent. The parameters for preparing the chitosan-sodium alginate composite microspheres by emulsification cross-linking are as follows: calcium chloride as the cross-linking agent, cross-linking temperature of 26-30℃, cross-linking time of 2-2.5 h, and a chitosan to sodium alginate mass ratio of 1:1.5. Under these parameters, the composite microspheres prepared have a stable structure and excellent protective effect.

[0027] The preferred thickness of the surface mulch layer is 6-7 cm, made from a mixture of well-rotted straw and coconut coir in a 3:2 mass ratio, and pulverized to a particle size of 1.5-2.5 mm. The loose texture of the well-rotted straw and coconut coir provides excellent water and fertilizer retention, reducing soil moisture evaporation and inhibiting weed growth. Furthermore, the decomposition process releases nutrients, improving soil fertility. The appropriate particle size after pulverization ensures both good air permeability and prevents uneven coverage due to excessively large particle sizes.

[0028] Step (2) Seed pretreatment directly affects seed germination rate and seedling resistance. Selecting plump Nanjing linden seeds is the foundation for ensuring germination rate. The dormancy-breaking treatment is as follows: soak the seeds in warm water at 41-44℃ for 24 hours. Soaking in warm water can soften the seed coat and promote seed water absorption. Then mix with wet sand at a mass ratio of 1:3 and stratify at low temperature at 6-12℃ for 32-38 days, maintaining the sand bed moisture content at 42-48%. Low temperature stratification can break seed dormancy, promote embryo development, and improve germination uniformity. In the salt tolerance induction treatment, seeds that have broken dormancy are soaked in a salt tolerance induction solution at room temperature for 13-17 hours. The salt tolerance induction solution is a mixture of 0.9-1.1 g / L proline solution and 0.6-0.7 g / L salicylic acid solution in a volume ratio of 1:1. Both proline and salicylic acid are substances related to plant stress resistance and can induce salt tolerance in seeds, thereby improving the seedlings' adaptability to saline-alkali environments. The amount of salt tolerance induction solution used is 600-700 mL per 100 g of seeds to ensure that the seeds fully absorb the effective components in the induction solution.

[0029] Step (3) Sowing and seedling cultivation stage: The preferred sowing depth is 2.1-2.8cm. Sowing too shallowly can easily lead to seed dehydration and drying, while sowing too deep will affect seed germination and emergence. The sowing density is 15-20 seeds per square meter. A reasonable sowing density can avoid seedling crowding and competition for nutrients and light, ensuring robust seedling growth. The cultivation temperature is controlled at 21-24℃, which is suitable for the germination of Nanjing linden seeds and seedling growth. The light duration is 8.5-9.5h / day. Sufficient light can promote seedling photosynthesis and accumulate nutrients. Spraying with a 1:500 diluted salt-tolerant bacterial agent every 8-9 days can continuously provide beneficial microorganisms for seedlings, enhance their salt resistance and immunity, and promote seedling growth. When the seedlings reach a height of 15-25cm, they have a certain degree of stress resistance and growth potential and can be transplanted.

[0030] Step (4) Planting and post-planting care are crucial for ensuring the survival and normal growth of Nanjing linden. After planting healthy seedlings in the planting area, irrigate with a salt-tolerant nutrient solution for root establishment. This solution is prepared by mixing 1.1-1.4 g / L potassium dihydrogen phosphate, 0.35-0.45 g / L borax, and 0.25-0.35 g / L brown algae extract, with the pH adjusted to 6.2-6.8. 2.2-2.8 L of solution is applied to each seedling. Potassium dihydrogen phosphate provides phosphorus and potassium to the seedlings, promoting root growth and plant resistance; borax promotes pollen germination and fruit development, increasing fruit set; brown algae extract enhances plant resistance and promotes growth; and a suitable pH and irrigation amount ensure that the seedlings fully absorb the nutrients in the nutrient solution, promoting rapid root development.

[0031] Regular water and fertilizer management is essential. Based on the growth stage of the Nanjing linden and soil fertility, apply nitrogen, phosphorus, and potassium fertilizers appropriately, avoiding excessive or insufficient fertilization that could negatively impact plant growth. Maintain suitable soil moisture, avoiding both drought and waterlogging. For disease control, adopt integrated pest management, prioritizing biological and physical control methods to reduce the use of chemical pesticides and minimize environmental pollution. Regularly inspect plant growth to promptly identify and address diseases. Monitor soil salinity monthly. When soil salinity exceeds 0.3%, open drainage ditches and spray a 2.0-2.8% citric acid solution every 10 days until the salinity drops below 0.3%. Through drainage and acid-base neutralization, effectively reduce soil salinity and prevent salt damage to the plants.

[0032] This invention provides a process for cultivating Nanjing linden in saline-tolerant coastal areas. Through pre-treatment of the planting site to construct a reasonable soil improvement structure and drainage system, combined with seed pre-treatment to improve seed salt tolerance, and with scientific sowing, cultivation, and transplanting maintenance measures, the successful cultivation of Nanjing linden in saline-tolerant coastal areas has been achieved. This process solves problems such as excessive soil salinity, insufficient fertility, and poor drainage in saline-tolerant coastal areas, improving the survival rate and growth quality of Nanjing linden. Furthermore, the process is simple to operate, cost-effective, and has good practicality and promotional value.

[0033] To further illustrate the present invention, the following detailed description is provided through the examples and comparative examples. Example

[0034] (1) Pretreatment of planting site: Deep plowing was carried out on the coastal salt-tolerant land to a depth of 38cm, followed by leveling. The planting area was divided into rows with a spacing of 2.8m and plants with a spacing of 2.0m. Drainage ditches were constructed with a spacing of 8.5m and a depth of 65cm, and the ditches were filled with gravel and non-woven fabric. To prepare the layered improved structure, a salt isolation layer was first prepared. Crushed brick slag, coarse sea sand, modified zeolite and nano zinc oxide particles were weighed in a mass ratio of 5:3:2:0.07. The modified zeolite was activated at 580℃ for 2.0h, cooled and crushed to a particle size of 2.5-4.5mm. 0.5% of the nano zinc oxide particles were added by mass, with a particle size of 60nm. The above components were put into a high-speed mixer and stirred at 1300r / min for 15min. After being mixed evenly, the mixture was laid with a thickness of 16cm to form a salt isolation layer. Next, a soil amendment layer was prepared. First, a modified composite salt-tolerant matrix was prepared. Raw material pretreatment: humus, bentonite, potassium feldspar, and brown algae extract were pulverized to a particle size of 0.15-0.25 mm. Modification treatment: humus and bentonite were mixed at a mass ratio of 3:1, and 12% of the total mass of a 6wt% citric acid solution was added. Modification was carried out at 31℃ for 26 hours, followed by drying until the moisture content was ≤8%, yielding the modified humus matrix. Composite preparation: the modified humus matrix was mixed with potassium feldspar and brown algae extract at a mass ratio of 8:1.5:0.5 and aged at 41℃ for 16 hours to obtain the modified composite salt-tolerant matrix. Garden soil, well-rotted green manure, the prepared modified composite salt-tolerant matrix, and a salt-tolerant bacterial agent were weighed at a mass ratio of 4:3:2:0.5. The salt-tolerant bacterial agent was a composite of Bacillus subtilis and humic acid bacteria, with a mass ratio of 2:1 and a viable count ≥2.5 × 10⁻⁵. 9 The salt-tolerant bacterial agent contains 0.35% of a bacterial protectant (CFU / g), which is a chitosan-sodium alginate composite microsphere with a particle size of 1.5 μm. It is prepared using an emulsification cross-linking method with the following parameters: calcium chloride as the cross-linking agent, cross-linking temperature of 26℃, cross-linking time of 2 h, and a chitosan to sodium alginate mass ratio of 1:1.5. After uniform mixing, the above components are laid on top of the salt isolation layer to a thickness of 25 cm, forming a soil amendment layer. Finally, a surface covering layer is prepared by weighing well-rotted straw and coconut coir at a mass ratio of 3:2, crushing them to a particle size of 1.5-2.5 mm, mixing them uniformly, and then laying them on top of the soil amendment layer to a thickness of 6 cm, forming the surface covering layer.

[0035] (2) Seed pretreatment: Select plump Nanjing linden seeds and perform dormancy-breaking treatment. Soak the seeds in 41℃ warm water for 24 hours, mix them with wet sand at a mass ratio of 1:3, and perform low-temperature stratification treatment at 6℃ for 32 days, maintaining the sand bed moisture content at 42%. Then, perform salt tolerance induction treatment. The salt tolerance induction solution is a mixture of 0.9 g / L proline solution and 0.6 g / L salicylic acid solution at a volume ratio of 1:1. Use 600 mL of induction solution for every 100 g of seeds. Soak the dormancy-breaking seeds in the salt tolerance induction solution at room temperature for 13 hours to obtain salt-tolerant pretreated seeds.

[0036] (3) Sowing and seedling cultivation: Sow the salt-tolerant pretreated seeds into the top layer of the layered modified structure at a depth of 2.1 cm and a density of 15 seeds per square meter. During cultivation, control the cultivation temperature at 21℃ and the light duration at 8.5 h / day. Spray with a 1:500 diluted salt-tolerant bacterial agent every 8 days until the seedlings reach a height of 15 cm to obtain robust seedlings.

[0037] (4) Planting and post-planting care: Plant healthy seedlings in the planting area. After planting, irrigate with a salt-tolerant nutrient solution for root establishment. The salt-tolerant nutrient solution is made by mixing 1.1 g / L potassium dihydrogen phosphate, 0.35 g / L borax and 0.25 g / L brown algae extract, and adjusting the pH to 6.2. Irrigate each seedling with 2.2 L. Regularly manage water and fertilizer and prevent and control diseases. The salt content is monitored once a month. When the soil salt content exceeds 0.3%, open the drainage ditch to drain the water. At the same time, spray a 2.0% citric acid solution every 10 days until the soil salt content drops below 0.3% and until the seedlings grow into mature plants. Example

[0038] (1) Pretreatment of planting site: Deep plowing was carried out on the coastal salt-tolerant land to a depth of 45cm, followed by leveling. The planting area was divided into rows with a spacing of 3.2m and plants with a spacing of 2.8m. Drainage ditches were constructed with a spacing of 9.5m and a depth of 75cm, and the ditches were filled with gravel and non-woven fabric. To prepare the layered improved structure, a salt isolation layer was first prepared. Crushed brick slag, coarse sea sand, modified zeolite and nano zinc oxide particles were weighed in a mass ratio of 5:3:2:0.07. The modified zeolite was activated at 625℃ for 2.5h, cooled and crushed to a particle size of 2.5-4.5mm. 0.9% of the nano zinc oxide particles were added by mass, with a particle size of 60nm. The above components were put into a high-speed mixer and stirred at 1400r / min for 18min. After being mixed evenly, the mixture was laid with a thickness of 20cm to form a salt isolation layer. Next, a soil amendment layer was prepared. First, a modified composite salt-tolerant matrix was prepared. Raw material pretreatment: humus, bentonite, potassium feldspar, and brown algae extract were pulverized to a particle size of 0.15-0.25 mm. Modification treatment: humus and bentonite were mixed at a mass ratio of 3:1, and 14% of the total mass of a 7wt% citric acid solution was added. The mixture was modified at 36℃ for 34 hours and then dried until the moisture content was ≤8%, obtaining the modified humus matrix. Composite preparation: the modified humus matrix was mixed with potassium feldspar and brown algae extract at a mass ratio of 8:1.5:0.5 and aged at 44℃ for 22 hours to obtain the modified composite salt-tolerant matrix. Garden soil, well-rotted green manure, the prepared modified composite salt-tolerant matrix, and a salt-tolerant bacterial agent were weighed at a mass ratio of 4:3:2:0.5. The salt-tolerant bacterial agent was a composite of Bacillus subtilis and humic acid bacteria, with a mass ratio of 2:1 and a viable count ≥2.5 × 10⁻⁵. 9 The salt-tolerant bacterial agent contains 0.45% of a bacterial protectant (CFU / g), which is a chitosan-sodium alginate composite microsphere with a particle size of 2.5 μm. It is prepared using an emulsification cross-linking method with the following parameters: calcium chloride as the cross-linking agent, cross-linking temperature of 30℃, cross-linking time of 2.5 h, and a chitosan to sodium alginate mass ratio of 1:1.5. After uniform mixing, the above components are laid on top of the salt isolation layer to a thickness of 28 cm, forming a soil amendment layer. Finally, a surface covering layer is prepared by weighing well-rotted straw and coconut coir at a mass ratio of 3:2, crushing them to a particle size of 1.5-2.5 mm, mixing them uniformly, and then laying them on top of the soil amendment layer to a thickness of 7 cm, forming the surface covering layer.

[0039] (2) Seed pretreatment: Select plump Nanjing linden seeds and perform dormancy-breaking treatment. Soak the seeds in 44℃ warm water for 24h, mix them with wet sand at a mass ratio of 1:3, and perform low-temperature stratification treatment at 12℃ for 38 days, maintaining the sand bed moisture content at 48%. Then, perform salt tolerance induction treatment. The salt tolerance induction solution is a mixture of 1.1g / L proline solution and 0.7g / L salicylic acid solution at a volume ratio of 1:1. Use 700mL of induction solution for every 100g of seeds. Soak the dormancy-breaking seeds in the salt tolerance induction solution at room temperature for 17h to obtain salt-tolerant pretreated seeds.

[0040] (3) Sowing and seedling cultivation: Sow the salt-tolerant pretreated seeds into the top layer of the layered modified structure at a depth of 2.8 cm and a density of 20 seeds per square meter. During cultivation, control the cultivation temperature at 24℃ and the light duration at 9.5 h / day. Spray with a 1:500 diluted salt-tolerant bacterial agent every 9 days until the seedlings reach a height of 25 cm to obtain robust seedlings.

[0041] (4) Planting and post-planting care: Plant healthy seedlings in the planting area. After planting, irrigate with a salt-tolerant nutrient solution for root establishment. The salt-tolerant nutrient solution is made by mixing 1.4 g / L potassium dihydrogen phosphate, 0.45 g / L borax and 0.35 g / L brown algae extract, and adjusting the pH to 6.8. 2.8 L of solution is applied to each seedling. Regular water and fertilizer management and disease control are carried out. Salt content is monitored once a month. When the soil salt content exceeds 0.3%, the drainage ditch is opened to drain the water. At the same time, a 2.8% citric acid solution is sprayed every 10 days until the soil salt content drops below 0.3% and until the seedlings grow into mature plants. Example

[0042] (1) Pretreatment of planting site: Deep plowing was carried out on the coastal salt-tolerant land to a depth of 42cm, followed by leveling. The planting area was divided into rows with a spacing of 3.0m and a plant spacing of 2.4m. Drainage ditches were constructed with a spacing of 9.0m and a depth of 70cm, and the ditches were filled with gravel and non-woven fabric. To prepare the layered improved structure, the salt isolation layer was first prepared. The crushed brick slag, coarse sea sand, modified zeolite and nano zinc oxide particles were weighed in a mass ratio of 5:3:2:0.07. The modified zeolite was activated at 600℃ for 2.2h, cooled and crushed to a particle size of 2.5-4.5mm. 0.7% of the nano zinc oxide particles were added by mass, with a particle size of 60nm. The above components were put into a high-speed mixer and stirred at 1350r / min for 16min. After being mixed evenly, the mixture was laid with a thickness of 18cm to form the salt isolation layer. Next, a soil amendment layer was prepared. First, a modified composite salt-tolerant matrix was prepared. Raw material pretreatment: humus, bentonite, potassium feldspar, and brown algae extract were pulverized to a particle size of 0.15-0.25 mm. Modification treatment: humus and bentonite were mixed at a mass ratio of 3:1, and 13% of the total mass of a 6.5 wt% citric acid solution was added. Modification was carried out at 33℃ for 30 hours, followed by drying until the moisture content was ≤8%, yielding the modified humus matrix. Composite preparation: the modified humus matrix was mixed with potassium feldspar and brown algae extract at a mass ratio of 8:1.5:0.5, and aged at 42℃ for 19 hours to obtain the modified composite salt-tolerant matrix. Garden soil, well-rotted green manure, the prepared modified composite salt-tolerant matrix, and a salt-tolerant bacterial agent were weighed at a mass ratio of 4:3:2:0.5. The salt-tolerant bacterial agent was a composite of Bacillus subtilis and humic acid bacteria, with a mass ratio of 2:1 and a viable count ≥2.5 × 10⁻⁵. 9 The salt-tolerant bacterial agent contains 0.40% of a bacterial protectant (CFU / g), which is a chitosan-sodium alginate composite microsphere with a particle size of 2.0 μm. It is prepared using an emulsification cross-linking method with the following parameters: calcium chloride as the cross-linking agent, cross-linking temperature of 28℃, cross-linking time of 2.2 h, and a chitosan to sodium alginate mass ratio of 1:1.5. After uniform mixing, the above components are laid on top of the salt isolation layer to a thickness of 26 cm, forming a soil amendment layer. Finally, a surface covering layer is prepared by weighing well-rotted straw and coconut coir at a mass ratio of 3:2, crushing them to a particle size of 1.5-2.5 mm, mixing them uniformly, and then laying them on top of the soil amendment layer to a thickness of 6.5 cm, forming the surface covering layer.

[0043] (2) Seed pretreatment: Select plump Nanjing linden seeds and perform dormancy-breaking treatment. Soak the seeds in 42℃ warm water for 24 hours, mix them with wet sand at a mass ratio of 1:3, and perform low-temperature stratification treatment at 9℃ for 35 days, maintaining the moisture content of the sand bed at 45%. Then, perform salt tolerance induction treatment. The salt tolerance induction solution is a mixture of 1.0 g / L proline solution and 0.65 g / L salicylic acid solution at a volume ratio of 1:1. Use 650 mL of induction solution for every 100 g of seeds. Soak the dormancy-breaking seeds in the salt tolerance induction solution at room temperature for 15 hours to obtain salt-tolerant pretreated seeds.

[0044] (3) Sowing and seedling cultivation: Sow the salt-tolerant pretreated seeds into the top layer of the layered modified structure at a depth of 2.5 cm and a density of 18 seeds per square meter. During cultivation, control the cultivation temperature at 22℃, the light duration at 9.0 h / day, and spray with a 1:500 diluted salt-tolerant bacterial agent every 8.5 days until the seedlings reach a height of 20 cm to obtain robust seedlings.

[0045] (4) Planting and post-planting care: Plant healthy seedlings in the planting area. After planting, irrigate with a salt-tolerant nutrient solution for root establishment. The salt-tolerant nutrient solution is made by mixing 1.2 g / L potassium dihydrogen phosphate, 0.40 g / L borax and 0.30 g / L brown algae extract, and adjusting the pH to 6.5. Irrigate each seedling with 2.5 L. Regularly manage water and fertilizer and prevent diseases. The salt content is monitored once a month. When the soil salt content exceeds 0.3%, open the drainage ditch to drain the water. At the same time, spray a 2.4% citric acid solution every 10 days until the soil salt content drops below 0.3% and until the seedlings grow into mature plants.

[0046] Comparative Example 1: The planting process of Example 3 is adopted, except that: in step (1) when preparing the salt isolation layer, no nano zinc oxide particles and modified zeolite are added, and the remaining components and dosages, preparation process and planting process are the same as those of Example 3.

[0047] Comparative Example 2: The planting process of Example 3 is adopted, the difference being that: in step (1) when preparing the soil amendment layer, the salt-tolerant bacteria agent does not contain chitosan-sodium alginate composite microspheres, while the remaining components and dosages, preparation process and planting process are the same as in Example 3.

[0048] Experiment: Determination of soil salinity and fertility indicators: Experimental Methods: Soil samples were collected from the planting areas of Examples 1-3 and Comparative Examples 1-2 before planting and one year after planting, respectively. Soil salinity, organic matter content, available nitrogen, available phosphorus, and available potassium were measured. Soil salinity was determined by gravimetric method, organic matter content by potassium dichromate titration method, available nitrogen by alkaline diffusion method, available phosphorus by molybdenum-antimony colorimetric method, and available potassium by flame photometry. The experimental results are as follows:

[0049]

[0050] One year after planting, the soil salinity in Examples 1-3 all decreased to below 0.3%, with Example 3 showing the lowest salinity at 0.22%. Simultaneously, the soil organic matter content and the contents of available nitrogen, phosphorus, and potassium all significantly increased. This indicates that the planting process of the present invention, through stratified structural improvement and scientific maintenance measures, effectively reduced soil salinity, enhanced soil fertility, and provided favorable soil conditions for the growth of Nanjing linden.

[0051] After one year of planting, the soil salinity in Comparative Example 1 was 0.45%, higher than that in Example 3, and the improvement in soil fertility indicators was also less than that in Example 3. The reason is that the absence of nano-zinc oxide particles and modified zeolite weakened the adsorption of soil salt and the inhibition of harmful microorganisms, resulting in a slow decrease in soil salinity. At the same time, it affected soil microbial activity, reduced the efficiency of organic matter decomposition and nutrient conversion, and led to insufficient improvement in soil fertility.

[0052] Comparative Example 2 showed the highest soil salinity (0.52%) after one year of planting, with the smallest improvement in soil fertility indicators among all treatments. The lack of chitosan-sodium alginate composite microspheres in the salt-tolerant bacterial agent significantly reduced its long-term effectiveness, hindering its ability to effectively activate soil nutrients and improve soil structure. Consequently, soil salinity was difficult to reduce effectively, limiting fertility improvement and ultimately impacting the growth of Nanjing linden and the improvement of the soil environment.

[0053] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not describe all details exhaustively, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification.

Claims

1. A process for planting Nanjing linden in salt-tolerant coastal areas, characterized in that, Includes the following steps: (1) Pretreatment of planting land: Deep plowing and leveling of coastal salt-tolerant land, dividing planting areas, and constructing drainage ditches; laying a layered improvement structure in the planting area, the layered improvement structure being, from bottom to top, a salt isolation layer, a soil improvement layer, and a surface covering layer; The salt isolation layer contains 0.5-0.9% nano zinc oxide particles by total mass, the nano zinc oxide particles having a particle size of 60-90 nm, which are then laid out after being mixed with other components of the salt isolation layer by high-speed stirring. The salt-tolerant bacterial agent added to the soil amendment layer contains 0.35-0.45% of a bacterial agent protectant, which is a chitosan-sodium alginate composite microsphere with a particle size of 1.5-2.5 μm, prepared by emulsification crosslinking method; (2) Seed pretreatment: Select plump Nanjing linden seeds and perform dormancy breaking treatment and salt tolerance induction treatment in sequence to obtain salt-tolerant pretreated seeds; (3) Sowing and seedling cultivation: Sow salt-tolerant pretreated seeds into the surface covering layer of the layered improved structure, control the sowing density and temperature and humidity, and cultivate the seedlings until the seedlings are 15-25cm tall to obtain robust seedlings; (4) Planting and post-planting care: Plant healthy seedlings in the planting area, and after planting, irrigate with salt-tolerant nutrient solution to help them establish roots. Regularly manage water and fertilizer, prevent and control diseases and monitor salt content until the seedlings grow into mature plants.

2. The process according to claim 1, characterized in that, In step (1), the deep plowing depth is 38-45cm, and the planting area is divided according to the row spacing of 2.8-3.2m and the plant spacing of 2.0-2.8m; the drainage ditch spacing is 8.5-9.5m and the depth is 65-75cm, and the ditch is filled with gravel and non-woven fabric; the speed of the high-speed stirring is 1300-1400r / min and the stirring time is 15-18min.

3. The process according to claim 1, characterized in that, The salt isolation layer is 16-20cm thick and is made by mixing crushed brick slag, coarse sea sand, modified zeolite and nano zinc oxide particles in a mass ratio of 5:3:2:0.

07. The modified zeolite is activated at 580-625℃ for 2.0-2.5h, cooled and then crushed to a particle size of 2.5-4.5mm.

4. The process according to claim 1, characterized in that, The soil amendment layer, with a thickness of 25-28 cm, is prepared by mixing garden soil, well-rotted green manure, modified composite salt-tolerant matrix, and salt-tolerant bacterial agent in a mass ratio of 4:3:2:0.

5. The salt-tolerant bacterial agent is a compound of Bacillus subtilis and humic acid bacteria in a mass ratio of 2:1, with a viable count ≥2.5 × 10⁻⁶. 9 cfu / g; The parameters for preparing chitosan-sodium alginate composite microspheres by the emulsification crosslinking method are as follows: calcium chloride is used as the crosslinking agent, the crosslinking temperature is 26-30℃, the crosslinking time is 2-2.5h, and the mass ratio of chitosan to sodium alginate is 1:1.

5.

5. The process according to claim 4, characterized in that, The preparation steps of the modified composite salt-resistant matrix include: (1) Raw material pretreatment: Humus, bentonite, potassium feldspar and brown algae extract were crushed to a particle size of 0.15-0.25 mm respectively; (2) Modification treatment: Mix humus and bentonite at a mass ratio of 3:1, add 12-14% of the total mass of 6-7wt% citric acid solution, modify at a constant temperature of 31-36℃ for 26-34h, and dry until the moisture content is ≤8% to obtain modified humus matrix. (3) Composite preparation: The modified humic matrix is ​​mixed with potassium feldspar and brown algae extract at a mass ratio of 8:1.5:0.5 and aged at a constant temperature of 41-44℃ for 16-22h to obtain the modified composite salt-resistant matrix.

6. The process according to claim 1, characterized in that, The surface covering layer is 6-7cm thick and is made of decomposed straw and coconut coir mixed in a mass ratio of 3:2 and crushed to a particle size of 1.5-2.5mm.

7. The process according to claim 1, characterized in that, In step (2), the dormancy breaking treatment is as follows: soak the seeds in warm water at 41-44℃ for 24 hours, mix them with wet sand at a mass ratio of 1:3, and perform low-temperature stratification treatment at 6-12℃ for 32-38 days, while maintaining the moisture content of the sand bed at 42-48%; in the salt tolerance induction treatment, the amount of salt tolerance induction solution used is 600-700mL of induction solution per 100g of seeds.

8. The process according to claim 1, characterized in that, In step (2), the salt tolerance induction treatment is as follows: the seeds after dormancy is broken are soaked in a salt tolerance induction solution at room temperature for 13-17 hours. The salt tolerance induction solution is a mixture of 0.9-1.1 g / L proline solution and 0.6-0.7 g / L salicylic acid solution in a volume ratio of 1:

1.

9. The process according to claim 1, characterized in that, In step (3), the sowing depth is 2.1-2.8cm, the sowing density is 15-20 seeds per square meter, the cultivation temperature is controlled at 21-24℃, the light duration is 8.5-9.5h / day, and a 1:500 diluted salt-tolerant bacterial agent is sprayed every 8-9 days.

10. The process according to claim 1, characterized in that, In step (4), the root-setting salt-tolerant nutrient solution is prepared by mixing 1.1-1.4 g / L potassium dihydrogen phosphate, 0.35-0.45 g / L borax and 0.25-0.35 g / L brown algae extract, and the pH is adjusted to 6.2-6.

8. 2.2-2.8 L is applied to each plant. The salt content is monitored once a month. When the soil salt content exceeds 0.3%, the drainage ditch is opened to drain the water. At the same time, a 2.0-2.8% citric acid solution is sprayed every 10 days until the soil salt content drops below 0.3%.

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