Seedling raising method for improving emergence rate and seedling survival rate of sand penis seeds

Abstract

The invention discloses a seedling raising method for improving the emergence rate and the seedling survival rate of sand penis seeds, and belongs to the technical field of plant seedling raising. The method comprises the steps that sandy soil or sandy loam 1 composed of specific particles is selected as a seedling raising substrate, the optimal sowing depth is matched according to the soil type, the sowing depth of the sandy soil is 1.5-2 cm, and the sowing depth of the sandy loam 1 is 1-1.5 cm; a 0.1%-0.3% potassium permanganate solution is adopted to disinfect the seeds before sowing. The coupling effect of the soil and the sowing depth on sand penis seedling raising is systematically illuminated for the first time, the emergence rate, the emergence uniformity and the seedling survival rate are remarkably increased by optimizing the combination of the soil proportion and the sowing depth, and growth of seedlings on the ground is promoted. The method is easy and convenient to operate, low in cost and suitable for large-scale seedling raising of the sand penis and desert ecological restoration, and has ecological and economic values.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of plant seedling raising, in particular to a seedling raising method for improving seed germination rate and seedling survival rate of Psammochloa villosa. BACKGROUND

[0002] Desertification is a major threat to global ecological security and one of the most important forms of land degradation worldwide. Currently, 40% of the world's land area is degraded, and nearly half of the world's population is directly or indirectly affected. In the face of this challenge, using plants to prevent wind and sand fixation is one of the long-term measures to solve land desertification and degradation.

[0003] Psammochloa villosa, as a sand pioneer grass, has developed rhizomes that can survive for more than 2 years. The rhizome branches can extend up to 28.1 m, and the extension length during the growing season (3 months) can reach 4.68 m, which can quickly form a clonal ramet network and effectively fix mobile sand. Psammochloa villosa has both ecological and economic values: ecologically, it is an advantage builder of mobile sand dunes and has strong drought resistance, which can quickly fix mobile sand and improve vegetation coverage; economically, it has high crude protein content during the vegetative period and is a high-quality forage for livestock, and its panicles are thick and long, with many large grains, which can be processed into premium feed. However, its natural seed setting rate is low (reproductive branches are inhibited by vegetative branches), and seeds are easily shed, and artificial propagation relies on seedling raising and transplanting, but low seed germination rate and unstable seedling survival rate are bottlenecks restricting its large-scale application.

[0004] Previous studies have focused on the effects of single factors such as sand burial depth, soil moisture, and temperature on seed germination and seedling growth of Psammochloa villosa, which has obvious limitations: first, the soil heterogeneity is ignored, and the water, air, and thermal conditions of different soil textures differ significantly, which directly affects the germination microenvironment. Field observations show that plant morphology differs greatly in different soil textures; second, there is a lack of interaction analysis, and the coupling effect of soil and sowing depth is not studied, such as the threshold effect of sowing depth on seed germination rate, seedling survival rate, and seedling height in different soils, which is not clear, resulting in a lack of scientific basis for soil configuration and sowing depth selection during artificial seedling raising. SUMMARY

[0005] To solve the above technical problems, the present application provides a seedling raising method for improving seed germination rate and seedling survival rate of Psammochloa villosa, which specifically comprises the following steps: A seedling raising method for improving seed germination rate and seedling survival rate of Psammochloa villosa, comprising the following steps: providing Psammochloa villosa seeds; selecting a seedling raising substrate, wherein the seedling raising substrate is sandy soil or sandy loam 1; sowing the Psammochloa villosa seeds in the seedling raising substrate at a sowing depth of 1-2 cm; the particle mass composition of the sandy loam 1 is: 2-0.2mm particle content is 14-15 parts; 0.2-0.02mm particle content is 69-70 parts; 0.02-0.002mm particle content is 5-6 parts; Particle content less than 0.002mm is 10-11 parts; The particle quality composition of the sandy soil is: 2-0.2mm particle content is 60-61 parts; 0.2-0.02mm particle content is 30-40 parts; 0.02-0.002mm particle content is 3-4 parts; Particle content less than 0.002mm is 1-5 parts.

[0006] Further, when the seedling substrate is sandy soil, the seeding depth is 1.5cm-2cm.

[0007] Further, when the seedling substrate is sandy soil, the seeding depth is 1.5cm-2cm.

[0008] Further, before seeding, the sand whip seed is subjected to disinfection treatment.

[0009] Further, the disinfection treatment is soaking with 0.1%-0.3% potassium permanganate solution for 3-10 minutes.

[0010] Further, the particle quality composition of the sandy soil is: 2-0.2mm particle content is 14.8 parts; 0.2-0.02mm particle content is 69.4 parts; 0.02-0.002mm particle content is 5.2 parts; Particle content less than 0.002mm is 10.5 parts.

[0011] Further, the chemical properties of the sandy soil meet: pH value is 9-10; Organic matter content is 4-5mg / kg; Hydrolytic nitrogen content is 140-150mg / kg; Available phosphorus content is 2.5-3.5mg / kg; Available potassium content is 42-46mg / kg.

[0012] Further, the particle quality composition of the sandy soil is: 2-0.2mm particle content is 60.7 parts; 0.2-0.02mm particle content is 34.1 parts; The content of 0.02-0.002mm particles is 3.2 parts; The content of particles smaller than 0.002mm is 2.0 parts.

[0013] Furthermore, the chemical properties of the sand satisfy the following: pH value is 8-9; The organic matter content is 1-3 mg / kg; The hydrolyzable nitrogen content is 60-65 mg / kg; The available phosphorus content is 2.0-3.0 mg / kg; The available potassium content is 38-42 mg / kg.

[0014] Furthermore, the field water holding capacity of the sandy soil is 15-18%, and the field water holding capacity of the sandy loam 1 is 18-80%.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. As a pioneering psammophytic grass, *Spodoptera litura* has significant value in ecological windbreak and sand fixation and economic forage utilization. However, the limitations of natural propagation and the low germination rate and unstable seedling survival rate in artificial propagation severely restrict its large-scale application. This invention clarifies the coupled influence of soil type and sowing depth on seedling survival rate. Using the technical solution of this invention, the seedling survival rate under sandy soil conditions generally exceeds 95%, reaching a maximum of 98.46%. The survival rate of sandy loam 1 at a suitable sowing depth also reaches 98.35%, providing a high survival rate technical guarantee for *Spodoptera litura* seedling cultivation and reducing replanting costs. In terms of germination rate, using the technical solution of this invention, the germination rate of sandy loam 1 at a sowing depth of 1.5cm reaches 71.6%, which is 24% higher than that of sandy loam 2, and the germination is uniform and rapid. Appropriate deep sowing (1.5-2cm) in sandy soil can significantly promote the growth of the above-ground parts of the seedlings, and the seedling height can reach 12.42cm, which is significantly higher than that of shallow sowing or sandy loam 2, which is conducive to cultivating strong seedlings and enhancing stress resistance.

[0016] 2. This invention fully considers the impact of soil heterogeneity on the germination and seedling growth of *Elaeagnus pungens* seeds. For two different soil textures, sandy soil and sandy loam, the particle composition was optimized. The water, air, and heat conditions of different soil textures differ significantly. By controlling the soil particle composition, a suitable microenvironment for seed germination was created, effectively improving the germination rate of *Elaeagnus pungens* seeds and solving the problem of previous single-factor studies neglecting soil heterogeneity. Simultaneously, based on the characteristics of different seedling substrates, a matching sowing depth was determined: 1.5cm-2cm for sandy soil and 1cm-1.5cm for sandy loam. This fully considers the coupling effect between soil and sowing depth, clarifying the threshold effect of sowing depth on germination rate, seedling survival rate, and seedling height in different soils. This provides a scientific basis for soil configuration and sowing depth selection in artificial seedling cultivation, improving the accuracy and success rate of seedling cultivation.

[0017] 3. The seedling raising method provided by this invention does not require complicated equipment, the substrate is readily available, the sowing depth is clear, and the disinfection treatment is simple. It is easy to promote and apply in desertification control areas, pastoral areas and seedling bases, and has high practical value and promotion prospects. Attached Figure Description

[0018] Figure 1 The effects of soil and sowing depth on the emergence rate of *Sargassum fusiforme*. Figure 2 The effects of soil and sowing depth on the emergence vigor of *Sargassum fusiforme*. Figure 3 The effects of soil and sowing depth on the emergence index of *Sargassum fusiforme*. Figure 4 The effects of soil and sowing depth on the survival rate of *Sargassum fusiforme* seedlings. Detailed Implementation

[0019] Example 1 A seedling cultivation method for improving the germination rate and seedling survival rate of *Sargassum fusiforme* seeds includes the following steps: Provide seeds of sand whip; Select a seedling substrate, wherein the seedling substrate is sandy soil; The seeds of the sand whip are sown in the seedling substrate at a depth of 1.5cm-2cm.

[0020] Preferably, the seeds of the sand whip are disinfected before sowing.

[0021] Preferably, the disinfection treatment involves soaking in a 0.1%-0.3% potassium permanganate solution for 3-10 minutes.

[0022] Preferably, the particle size composition of the sand is as follows: The content of particles with a diameter of 2-0.2mm is 60-61 parts; The content of particles with a diameter of 0.2-0.02mm is 30-40 parts; The content of 0.02-0.002mm particles is 3-4 parts; The content of particles smaller than 0.002mm is 1-5 parts.

[0023] Preferably, the field water holding capacity of the sandy soil is 15-18%.

[0024] Example 2 Based on Example 1, the chemical properties of the sand satisfy the following: pH value is 8-9; The organic matter content is 1-3 mg / kg; The hydrolyzable nitrogen content is 60-65 mg / kg; The available phosphorus content is 2.0-3.0 mg / kg; The available potassium content is 38-42 mg / kg.

[0025] Example 3 A seedling cultivation method for improving the germination rate and seedling survival rate of *Sargassum fusiforme* seeds includes the following steps: Provide seeds of sand whip; Select a seedling substrate, wherein the seedling substrate is sandy loam soil 1; The seeds of the sand whip are sown in the seedling substrate at a depth of 1cm-1.5cm.

[0026] Preferably, the particle size distribution of the sandy loam 1 is as follows: The content of 2-0.2mm particles is 14-15 parts; The content of particles with a diameter of 0.2-0.02mm is 69-70 parts; The content of 0.02-0.002mm particles is 5-6 parts; The content of particles smaller than 0.002mm is 10-11 parts.

[0027] Preferably, the seeds of the sand whip are disinfected before sowing.

[0028] Preferably, the disinfection treatment involves soaking in a 0.1%-0.3% potassium permanganate solution for 3-10 minutes.

[0029] Preferably, the field water holding capacity of the sandy loam 1 is 18-80%.

[0030] Example 4 Based on Example 3, the chemical properties of the sandy loam 1 satisfy the following: pH value is 9-10; The organic matter content is 4-5 mg / kg; The hydrolyzable nitrogen content is 140-150 mg / kg; The available phosphorus content is 2.5-3.5 mg / kg; The available potassium content is 42-46 mg / kg.

[0031] Experimental Section 1. Materials and Methods 1.1 Experimental Materials The seeds of *Saussurea involucrata* were collected in July 2024 in Bayanmuren Sumu, Alxa League, Inner Mongolia. After drying and preliminary cleaning, the collected seeds were stored in a short-term warehouse (4-6℃) in October. In early May 2025, the seeds were retrieved, and plump, uniformly sized, and mold-free seeds were selected. The seeds were then disinfected by soaking in a 0.2% potassium permanganate solution for 5 minutes, rinsed five times with distilled water, and blotted dry with filter paper for later use. Seed characteristics are shown in Table 1.

[0032] Sandy soil from the original seed collection site, sandy loam soil 1 from the surrounding planting site, and sandy loam soil 2 were all collected. After impurities were removed by sieving through a 2mm sieve, they were sterilized at 105℃ for 48 hours. The basic soil conditions are shown in Tables 2 and 3.

[0033] Table 1. Information on seeds of *Vitis amurensis*

[0034] Table 2 Soil Physical Properties

[0035] Table 3 Soil Chemical Properties

[0036] 1.2 Experimental Content and Methods A two-factor, completely randomized pot experiment was conducted. Three soil treatment levels were set: sandy soil (A1), sandy loam 1 (A2), and sandy loam 2 (A3). Four sowing depth levels were set: 0.5 cm (B1), 1 cm (B2), 1.5 cm (B3), and 2 cm (B4), for a total of 12 treatments. Each treatment was replicated three times, with 50 seeds planted in each replicate. On May 15, 2025, the three soil treatments were placed in pots with a diameter of 15 cm and a depth of 20 cm. After leveling and lightly pressing, the soil depth was ensured to be approximately 18 cm. Sterilized seeding sticks were used to make holes at the different sowing depths. Seeds were sown with tweezers and then lightly pressed to cover the seeds, ensuring close contact between the seeds and the soil. The flowerpots were placed in a glass greenhouse. During the experiment, the indoor temperature ranged from 6.8℃ to 39.3℃, and the relative humidity ranged from 24% to 95%. The soil moisture content of each treatment was precisely controlled to be 70% of the field capacity by weighing. Water was added after weighing with an electronic balance every day to ensure that the soil moisture content was always maintained at the set target value.

[0037] 1.3 Methods for determining and calculating indicators Starting from May 16, 2025, the number of seedlings was recorded daily for 25 consecutive days. On the 25th day after sowing, 10 seedlings were randomly selected and their height was measured using a ruler. On the 60th day, the number of surviving seedlings was counted.

[0038] Germination rate (ER) (%) = Number of germinated seeds (at the end of germination period) / Number of tested seeds × 100%; Emergence potential (EP) (%) = Number of seeds that emerge at peak emergence time (11 days) / Number of seeds tested × 100%; Germination Index (EI) = Σ(Gt / Dt). Where Gt is the number of germinating seeds on day t, and Dt is the corresponding number of days for seed germination.

[0039] Seedling survival rate (SSR) (%) = Number of seedlings surviving (60 days) / Number of seedlings emerging × 100%.

[0040] 1.4 Data Analysis Data were processed and statistically analyzed using Excel 2024 and SPSS 31.0. Data that met the requirements of homogeneity of variance and normality, or those that met these requirements after transformation, underwent two-way ANOVA. For data with significant interaction effects, simple effects analysis was performed. Tukey's HSD test was used for multiple comparisons to identify differences between groups. For data that did not meet the requirements after transformation, the median and 25th and 75th percentiles [M(P25, P75)] were used for description, and two-way nonparametric ANOVA with the Scheirer-Ray-Hare test was employed. When main effects were significant but interaction effects were not, the Kruskal-Wallis H test was used. Post-hoc comparisons were performed using the Dunn test with Bonferroni correction.

[0041] 2. Results and Analysis In the following results, A1, A2, and A3 represent soil types 1 (sandy soil), 2 (sandy loam soil), and 3 (sandy loam soil), respectively; B1, B2, B3, and B4 represent sowing depths of 0.5 cm, 1 cm, 1.5 cm, and 2 cm, respectively. Different lowercase letters indicate significant differences between different sowing depths within the same soil type, while different uppercase letters indicate significant differences between different soil types at the same sowing depth (P < 0.05).

[0042] 2.1 Effects of Soil and Sowing Depth on Emergence Indicators Depend on Figure 1It can be seen that the emergence rate in soil A1 generally increased with increasing sowing depth, reaching a maximum of 60.2% in B4; in A2, it first increased and then decreased with increasing sowing depth, reaching a maximum of 71.6% in B3; in A3, it first slightly increased and then decreased with increasing sowing depth, reaching a maximum of 54.8% in B2. At the same sowing depth, the emergence rate showed a trend of first increasing and then decreasing with the change from sandy soil to sandy loam. In the B2-B3 sowing depth treatments, the A2 treatment group was significantly higher than the A1 and A3 treatment groups (P<0.05). Specifically, in the B2 treatment, the A2B2 group was 9.6% and 13.2% higher than the A1B2 and A3B2 combinations, respectively; in the B3 treatment, the A2B3 group was 13.6% and 23.2% higher than the A1B3 and A3B3 combinations, respectively. In the B4 sowing depth treatment, the A1 and A2 groups were significantly higher than the A3 treatment group (P<0.05). Overall, the A2B3 combination had the highest germination rate at 71.6%, while the A3B4 combination had the lowest at 47.6%, with the A2B3 combination achieving a germination rate 24% higher than the A3B4 combination.

[0043] Depend on Figure 2 It was found that seedling vigor decreased with increasing sowing depth in soils A1 and A3, while in A2 it first increased and then decreased with increasing sowing depth, reaching a maximum of 45.2% in B2. At the same sowing depth, seedling vigor showed a trend of first increasing and then decreasing as the soil changed from sandy soil to sandy loam. Within the range of treatments B2-B4, treatment group A2 was significantly higher than treatment groups A1 and A3 (P<0.05). Specifically, in treatment B2, A2B2 was 14% and 10% higher than A1B2 and A3B2, respectively; in treatment B3, A2B3 was 33.2% and 20% higher than A1B3 and A3B3, respectively; and in treatment B4, A2B4 was 27.2% and 14.8% higher than A1B4 and A3B4, respectively. Overall, the seedling vigor of combination A2B2 was the highest at 45.2%, while that of combination A1B4 was the lowest at 5.6%, with A2B2 being 39.6% higher than A1B4.

[0044] Depend on Figure 3It can be seen that, under the same soil conditions, the emergence index first increased and then decreased with increasing sowing depth. For soils A1 and A3, both reached their maximum at sowing depth B2; while for soil A2, the maximum was reached at sowing depth B3. At treatment B1, there was no significant difference in sowing depth among treatments; within the range of treatments B2-B4, treatment A2 was significantly higher than treatments A1 and A3 (P<0.05). Specifically, in treatment B2, A2B2 was 0.89 and 0.6 higher than the combinations A1B2 and A3B2, respectively; in treatment B3, A2B3 was 1.14 and 1.18 higher than the combinations A1B3 and A3B3, respectively; and in treatment B4, A2B4 was 0.97 and 0.99 higher than the combinations A1B4 and A3B4, respectively. In summary, different soil types and sowing depths have a significant impact on the emergence index of *Sargassum fusiforme*. The A2B3 combination has the highest emergence index at 3.26, while the A3B4 combination has the lowest at 2.02. The emergence index of A2B3 is 1.24 higher than that of A3B4.

[0045] Analysis of variance (Table 4) showed that soil, sowing depth, and soil × sowing depth all had extremely significant effects on emergence rate, emergence vigor, and emergence index of *Sargassum fusiforme* (P < 0.01), with soil having a greater impact on the emergence index than sowing depth. Among the interaction effects, the synergistic regulation of emergence vigor was more pronounced.

[0046] Table 4. Analysis of variance on seedling emergence index of *Euphorbia milii* and soil conditions.

[0047] Note: A, B, and A×B represent soil, sowing depth, and soil×sowing depth, respectively; * and ** indicate significant effects at the 0.05 and 0.01 levels, respectively, and the same applies below.

[0048] 2.2 Effects of Soil and Sowing Depth on the Survival Rate of *Sargassum fusiforme* Seedlings Depend on Figure 4 It can be seen that at the B1 sowing depth, the survival rates of A1B1 and A2B1 were 5.35% and 15.82% higher than those of A3B1, respectively; at sowing depths of B2-B4, the A1 treatment group was significantly higher than the A2 and A3 treatment groups (P<0.05); at the B2 sowing depth, the survival rate of the A1B2 treatment group was 11.81% and 17.82% higher than that of the A2B2 and A3B2 combinations, respectively; in the B3 treatment, the A1B3 group was 16.15% and 16.53% higher than that of the A2B3 and A3B3 combinations, respectively; in the B4 treatment, the A1B4 group was 15.35% and 27.65% higher than that of the A2B4 and A3B4 combinations, respectively. Overall, the A1B4 combination had the highest seedling survival rate at 98.46%, the A2B3 combination also had a relatively high seedling survival rate of 98.35%, and the A3B4 combination had the lowest at 70.81%.

[0049] Analysis of variance (Table 5) showed that soil, sowing depth, and soil × sowing depth all had extremely significant effects on the survival rate of seedlings of *Sargassum fusiforme* (P<0.01), with soil having a greater impact on seedling survival than sowing depth.

[0050] Table 5. Analysis of variance on the survival rate of *Elaeagnus angustifolia* seedlings affected by soil type and sowing depth.

[0051] 2.3 Effects of Soil and Sowing Depth on the Height of *Sargassum fusiforme* Table 6 shows that when the soil types are A1 and A3, the seedling height increases with increasing sowing depth. When the soil type is A2, the seedling height first increases and then decreases with increasing sowing depth, reaching its maximum at sowing depth B3. Under sandy soil (A1) conditions, the seedling height of combinations A1B2, A1B3, and A1B4 exceeded 9 cm. Overall, combination A1B4 had the highest seedling height at 12.42 cm, while combination A3B1 had the lowest at 3.6 cm. Combination A1B4 was 8.82 cm taller than combination A3B1.

[0052] Table 6. Effects of soil and sowing depth on seedling height of *Sargassum fusiforme* [Median (25th percentile, 75th percentile)]

[0053] Nonparametric analysis of variance and multiple comparisons (Tables 7 and 8) showed that soil and sowing depth both had extremely significant effects on the seedling height of *Sargassum fusiforme* (P<0.01), with soil having a greater impact on seedling height than sowing depth. At the same sowing depth, seedling height in treatment groups A2 and A3 was significantly lower than that in treatment group A1 (P<0.01); while in the same soil conditions, treatment groups B3 and B4 were significantly higher than that in treatment group B1 (P<0.01). In summary, soil conditions A1 significantly increased seedling height in *Sargassum fusiforme*; sowing depths B3-B4 also significantly increased seedling height. However, sandy loam 1, sandy loam 2, or shallow sowing were all detrimental to the aboveground growth of *Sargassum fusiforme* seedlings.

[0054] Table 7. Results of multiple comparisons of soil type and sowing depth on seedling height of *Euphorbia milii*

[0055] Each row tests the null hypothesis that "sample 1 and sample 2 have the same distribution". Asymptotic significance is shown (two-tailed test) at a significance level of 0.05. Significance values ​​have been adjusted for multiple tests using Bonferroni correction. Effect size r strength: small effect (0.1-0.3), medium effect (0.3-0.5), large effect (≥0.5).

[0056] Table 8. Nonparametric analysis of variance of soil and sowing depth on seedling height of *Ligustrum lucidum*.

[0057] 3. Conclusion This invention systematically investigated the effects of sowing depth on the germination and seedling growth rate of *Ligustrum lucidum* seeds in different soils, and drew the following main conclusions: Soil significantly affects the germination of *Ligustrum lucidum* seeds. The germination rate, germination potential, and germination index under sandy loam 1 and sandy soil conditions were significantly higher than those under sandy loam 2 (P < 0.05). Sowing depth has a significant impact on the germination of *Ligustrum lucidum* seeds. With increasing sowing depth, different soils showed different emergence characteristics. When the seedling substrate was sandy soil and the sowing depth was 1.5 cm-2 cm, the emergence rate was high when the seedling substrate was sandy loam 1 and the sowing depth was 1 cm-1.5 cm, while the effect was poor in sandy loam 2. A significant interaction exists between soil and sowing depth when the sowing depth is 1-2 cm in both sandy soil and sandy loam 1. The effect of sowing depth is more significant in sandy loam 2 and relatively smaller in sandy loam 1.

Claims

1. A method for improving the germination rate and seedling survival rate of *Sargassum fusiforme* seeds, characterized in that, Includes the following steps: Provide seeds of sand whip; Select a seedling substrate, wherein the seedling substrate is sandy soil or sandy loam 1; The seeds of the sand whip are sown in the seedling substrate at a depth of 1-2 cm. The particle size composition of the sandy loam soil 1 is as follows: The content of 2-0.2mm particles is 14-15 parts; The content of particles with a diameter of 0.2-0.02mm is 69-70 parts; The content of 0.02-0.002mm particles is 5-6 parts; The content of particles smaller than 0.002mm is 10-11 parts; The particle size composition of the sand is as follows: The content of particles with a diameter of 2-0.2mm is 60-61 parts; The content of particles with a diameter of 0.2-0.02mm is 30-40 parts; The content of 0.02-0.002mm particles is 3-4 parts; The content of particles smaller than 0.002mm is 1-5 parts.

2. The seedling raising method according to claim 1, characterized in that, When the seedling substrate is sandy soil, the sowing depth is 1.5cm-2cm.

3. The seedling raising method according to claim 1, characterized in that, When the seedling substrate is sandy loam, the sowing depth is 1cm-1.5cm.

4. The seedling raising method according to any one of claims 1-3, characterized in that, Before sowing, the seeds of the sand whip are disinfected.

5. The seedling raising method according to claim 4, characterized in that, The disinfection process involves soaking the affected area in a 0.1%-0.3% potassium permanganate solution for 3-10 minutes.

6. The seedling raising method according to claim 1, characterized in that, The particle size composition of the sandy loam soil 1 is as follows: The content of 2-0.2mm particles was 14.8 parts; The content of particles with a diameter of 0.2-0.02 mm was 69.4 parts. The content of 0.02-0.002mm particles is 5.2 parts; The content of particles smaller than 0.002 mm is 10.5 parts.

7. The seedling raising method according to claim 1, characterized in that, The chemical properties of the sandy loam soil 1 satisfy the following: pH value is 9-10; The organic matter content is 4-5 mg / kg; The hydrolyzable nitrogen content is 140-150 mg / kg; The available phosphorus content is 2.5-3.5 mg / kg; The available potassium content is 42-46 mg / kg.

8. The seedling raising method according to any one of claims 1-3, characterized in that, The particle size composition of the sand is as follows: The content of 2-0.2mm particles was 60.7 parts; The content of particles with a diameter of 0.2-0.02mm is 34.1 parts; The content of 0.02-0.002mm particles is 3.2 parts; The content of particles smaller than 0.002mm is 2.0 parts.

9. The seedling raising method according to claim 1, characterized in that, The chemical properties of the sandy soil satisfy the following: pH value is 8-9; The organic matter content is 1-3 mg / kg; The hydrolyzable nitrogen content is 60-65 mg / kg; The available phosphorus content is 2.0-3.0 mg / kg; The available potassium content is 38-42 mg / kg.

10. The seedling raising method according to claim 1, characterized in that, The field water holding capacity of the sandy soil is 15-18%, and the field water holding capacity of the sandy loam 1 is 18-80%.

Images