A method for increasing the greening of Pinus sylvestris var. mongolica in winter and improving its cold resistance

Abstract

The present invention discloses a method for increasing the greening and cold resistance of Pinus sylvestris var. mongolica in winter. A water and fertilizer integration system is used to drip-irrigate and fertilize Pinus sylvestris var. mongolica. 1 to 3 months before the dormancy period, fertilization is carried out at 1 / 3 to 1 / 2 of the single recommended fertilization amount during the rapid growth period, and drip irrigation is carried out at 2 / 3 to 4 / 5 of the single recommended irrigation amount during the rapid growth period. Through continuous research, the inventor found that by reducing the fertilization amount and irrigation amount, the antioxidant enzyme activity in winter can be enhanced, the cold resistance of Pinus sylvestris var. mongolica can be improved, and at the same time, leaf chlorosis can be reduced. In particular, the relative conductivity of Pinus sylvestris var. mongolica treated by the method of the present invention is reduced to 24.31%, and the MDA content is 113.14 nmol / gDW, which is lower than that of the conventional irrigation and fertilization treatment, the treatment of only drip irrigation without fertilization, and the water and fertilizer integration treatment with higher fertilization amount and irrigation amount, and the cold resistance performance is the best.

Description

Technical Field

[0001] The present invention belongs to the technical field of garden tree cultivation, relates to a cultivation and management method of Pinus sylvestris var. mongolica, and particularly relates to a method for enhancing cold resistance and greening of Pinus sylvestris var. mongolica. Background Art

[0002] According to the prior research results of the applicant, after assembling large-sized balled seedlings into container seedlings and using the integrated water and fertilizer technology, the rapid seedling recovery and growth of the balled seedlings in the containers are promoted, and the cultivation goal of rapid seedling establishment and strong seedling growth of large-sized container seedlings of Pinus sylvestris var. mongolica is achieved.

[0003] According to the continuous research of the inventor team on the integrated water and fertilizer of Pinus sylvestris var. mongolica, the inventors found that at least one of the following technical problems exists in the prior art:

[0004] 1. Under the traditional concept, people believe that reasonable fertilization during the growth season will promote plant growth, while fertilization from the end of the growth season to before dormancy will affect the normal dormancy of seedlings, reduce the cold resistance of plants, and make them unable to overwinter normally;

[0005] 2. Although Pinus sylvestris var. mongolica has strong cold resistance, drought resistance, barren tolerance and strong stress resistance, and is an important tree species for ecological restoration in resource-deficient water areas in China. Because of the strong stress resistance of Pinus sylvestris var. mongolica itself, the prior art ignores the research on enhancing the cold resistance of Pinus sylvestris var. mongolica;

[0006] 3. In the construction and management of Pinus sylvestris var. mongolica landscape forests, except for the applicant, no relevant research on the integrated water and fertilizer technology has been carried out. The demand law of tree species for water and fertilizer is still not fully understood, the suitable water and fertilizer combination ratio is not clear, and it cannot be evaluated through indicators such as yield and economic benefits, which severely restricts the application of this efficient cultivation technology in ecological landscape construction;

[0007] 4. The research on the reasonable fertilization amount of Pinus sylvestris var. mongolica mainly focuses on 1-3-year-old field-grown seedlings and container seedlings, and further research on the nutrient management of established seedlings of Pinus sylvestris var. mongolica is needed;

[0008] 5. For ecological landscape tree species, in the process of high-quality cultivation of Pinus sylvestris var. mongolica landscape forests, there is a lack of guidance from scientific research results, and an efficient cultivation technology system with closely linked links has not been formed, which is a problem to be further studied in China's ecological construction;

[0009] 6. There is a phenomenon of "planting without management" in the cultivation of Pinus sylvestris var. mongolica, resulting in the inability of large-sized container seedlings to play their due advantages after being transplanted for afforestation;

[0010] 7. As an ecological landscape tree species, people are used to the grayish-green leaves of Pinus sylvestris var. mongolica in winter, and there are no ideas and technical means for its winter greening.

[0011] For afforestation with large-sized container seedlings, how to improve winter cold resistance and maintain the greenness of leaves in winter is also an important indicator to ensure the winter landscape effect of large-sized Pinus sylvestris var. mongolica seedlings. Summary of the Invention

[0012] In view of this, the purpose of the present invention is to provide a method for improving the winter cold resistance of Pinus sylvestris var. mongolica and reducing the chlorosis of its leaves in winter.

[0013] Through long-term exploration and attempts, as well as multiple experiments and efforts, and continuous reform and innovation, in order to solve the above technical problems, the technical solution provided by the present invention is to provide a method for increasing the greenness and cold resistance of Pinus sylvestris var. mongolica in winter, using a water and fertilizer integration system to drip-irrigate and fertilize Pinus sylvestris var. mongolica, and fertilizing at 1 / 3 - 1 / 2 of the single recommended fertilization amount during the rapid growth period 1 - 3 months before the dormancy period, and drip-irrigating at 2 / 3 - 4 / 5 of the single recommended irrigation amount during the rapid growth period.

[0014] The single recommended fertilization amount during the rapid growth period and the single recommended irrigation amount during the rapid growth period described in the present invention refer to the fertilization amount and irrigation amount that are more suitable for the accumulation of carbohydrates during the rapid growth period of Pinus sylvestris var. mongolica and enhance the tree vigor.

[0015] According to an embodiment of the method for increasing the greenness and cold resistance of Pinus sylvestris var. mongolica in winter of the present invention, fertilize at 1 / 3 of the single recommended fertilization amount during the rapid growth period 2 - 3 months before the dormancy period, and drip-irrigate at 3 / 4 of the single recommended irrigation amount during the rapid growth period.

[0016] According to an embodiment of the method for increasing the greenness and cold resistance of Pinus sylvestris var. mongolica in winter of the present invention, the Pinus sylvestris var. mongolica is a 9-year-old Pinus sylvestris var. mongolica.

[0017] According to an embodiment of the method for increasing the greenness and cold resistance of Pinus sylvestris var. mongolica in winter of the present invention, the Pinus sylvestris var. mongolica is a large-sized container transplanted seedling of 9-year-old Pinus sylvestris var. mongolica that has been cultivated in an above-ground container for 1 year.

[0018] According to an embodiment of the method for increasing the greenness and cold resistance of Pinus sylvestris var. mongolica in winter of the present invention, drip-irrigate 32 L / plant·time of water and 25 g / plant·time of water-soluble compound fertilizer to the roots of Pinus sylvestris var. mongolica 1 - 3 months before the dormancy period.

[0019] According to an embodiment of the method for increasing the greenness and cold resistance of Pinus sylvestris var. mongolica in winter of the present invention, the water-soluble compound fertilizer has N∶P2O5∶K2O = 20∶20∶20.

[0020] According to an embodiment of the method for increasing the greenness and cold resistance of Pinus sylvestris var. mongolica in winter of the present invention, the method is applied to a semi-arid continental monsoon climate region.

[0021] According to an embodiment of the method for enhancing the winter greening and cold resistance of Pinus sylvestris var. mongolica, water and fertilizer are drip-irrigated once every 7 - 8 days, for a total of 9 - 10 times, and each drip irrigation lasts for 3 - 5 hours.

[0022] According to an embodiment of the method for enhancing the winter greening and cold resistance of Pinus sylvestris var. mongolica, the recommended fertilization amount and the recommended irrigation amount are scientifically determined based on phenological conditions, as well as the new shoot growth amount, ground diameter growth amount, starch content, soluble sugar content, and promotion results of photosynthetic pigments of Pinus sylvestris var. mongolica under fertilization conditions.

[0023] According to an embodiment of the method for enhancing the winter greening and cold resistance of Pinus sylvestris var. mongolica, the single recommended fertilization amount during the rapid growth period is 75 g / plant, and the single recommended irrigation amount is 32 L / plant.

[0024] Compared with the prior art, one of the above technical solutions has the following advantages:

[0025] a) The applicant's previous research proposed that when the relative conductivity > 40%, it is necessary to supply water and fertilizer to large container seedlings of Pinus sylvestris var. mongolica in a refined manner, that is, the upper limit requirement of relative conductivity was proposed, but at that time, it was not realized to explore and achieve the lowest achievable value of the relative conductivity of Pinus sylvestris var. mongolica. Through continuous research, the inventor found that drip irrigation and fertilization integration can improve the cold resistance of Pinus sylvestris var. mongolica leaves in winter. Especially, under the treatment of the method of the present invention, the relative conductivity of Pinus sylvestris var. mongolica drops to 24.31%, and the MDA content is 113.14 nmol / gDW, which is lower than that of the conventional irrigation and fertilization treatment, the treatment of only drip irrigation without fertilization, and the drip irrigation and fertilization integration treatment with higher fertilization amount and irrigation amount, and the cold resistance performance is the best.

[0026] b) The inventor found through exploration experiments that compared with Pinus sylvestris var. mongolica in the growing season, the chlorophyll content of each water and fertilizer treatment in winter decreased significantly, but the attenuation amplitude of chlorophyll under the treatment of the method of the present invention was lower, maintaining a relatively high chlorophyll content, which plays an important role in reducing leaf chlorosis in winter and improving the winter landscape effect of Pinus sylvestris var. mongolica.

[0027] c) Drip irrigation according to the recommended fertilization amount and the recommended irrigation amount during the rapid growth period can promote the progress of photosynthesis and the accumulation of carbohydrates, and enhance the tree vigor; from the late growth stage to the stage before dormancy, the growth rate of Pinus sylvestris var. mongolica slows down until it stops, but its respiration and photosynthesis do not stop. By reducing the fertilization amount and irrigation amount, the antioxidant enzyme activity in winter can be enhanced, the cold resistance of Pinus sylvestris var. mongolica can be improved, and at the same time, leaf chlorosis can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0029] Figure 1 It is the influence of drip irrigation and fertilization integration on the relative conductivity of Pinus sylvestris var. mongolica leaves in winter.

[0030] Figure 2 It is the influence of fertilization amount on the SOD activity of Pinus sylvestris var. mongolica leaves in winter.

[0031] Figure 3 It is the influence of fertilization amount on the photosynthetic pigment content of Pinus sylvestris var. mongolica leaves in winter.

[0032] Figure 4 It is the influence of drip irrigation and fertilization integration on the chlorophyll content of Pinus sylvestris var. mongolica leaves in winter.

[0033] Figure 5 It is a figure of Pinus sylvestris var. mongolica leaves in winter. a is the treatment of the present invention, b is the traditional irrigation and fertilization treatment, and c is the treatment of only drip irrigation without fertilization. Specific Embodiments

[0034] The following will be described in conjunction with the drawings and a specific embodiment.

[0035] To make the purpose, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents the selected embodiments of the present invention.

[0036] This embodiment of the experiment was carried out in the Xuanhua Experimental Base of the Chinese Academy of Forestry Sciences in Xuanhua District, Zhangjiakou City (40°37′N, 115°03′E). The area has a semi-arid continental monsoon climate, with dry springs, short and hot summers, concentrated precipitation, cool and rapidly cooling autumns, long, cold, and snowy winters, often accompanied by severe temperature drops and strong winds. The annual average temperature is 7.6 °C, the annual precipitation is 300 - 400 mm, and the annual frost-free period is 219 days.

[0037] In the first ten days of June 2022, large-sized container seedlings of 9-year-old Pinus sylvestris var. mongolica that had been cultivated in above-ground containers for 1 year were selected for afforestation experiments. Healthy Pinus sylvestris var. mongolica with similar growth and no pests and diseases were selected. The average plant height of the experimental seedlings was 3.02 m, and the average ground diameter was 6.2 cm. The root control container was a non-woven fabric planting bag, the diameter of the soil ball was 50 cm, and the height of the soil ball was 40 cm. When transplanting, the container was removed, and afforestation was carried out at a plant spacing of 3 m × 3 m, with 14 plants in the east-west direction and 13 plants in the north-south direction, as the experimental plot for drip irrigation and fertilization integration treatment. The outermost row of Pinus sylvestris was used as a protection row. When afforesting, the original orientation of Pinus sylvestris was kept unchanged.

[0038] A split-plot experimental design was adopted, with the fertilization rate set as the main plot and the irrigation rate as the sub-plot (Table 1). A total of three blocks were set, with 3 main plots and 3 sub-plots in each block. Four seedlings were arranged in each small plot. A total of 108 Pinus sylvestris were used in the entire drip irrigation and fertilization integration split-plot experiment.

[0039] The fertilization rate (F) was arranged in the main plot, and the fertilizer was a water-soluble compound fertilizer (N∶P2O5∶K2O = 20∶20∶20), which was required to be highly soluble in water, and the formed fertilizer solution was uniform and stable. The single fertilization rate was set at 3 levels, namely low fertilizer F1 (25 g / plant), medium fertilizer F2 (50 g / plant), and high fertilizer F3 (75 g / plant), each equipped with a fertilization bucket with a flow regulating valve. 16 L of water was injected into the 3 fertilization buckets according to the single irrigation rate per plant, and after adding fertilizer, it was stirred evenly. The fertilizer solution concentrations in each fertilization bucket were 1.56 g / L, 3.12 g / L, and 4.69 g / L in sequence. A combination of a fertilization bucket + an increasing pump + a PE pipe + a steady-flow drip emitter was used to supply fertilizer to the seedlings. Four steady-flow drip emitters were inserted at a distance of 15 cm from the rootstock in the four directions of east, south, west, and north of each seedling, and the single drip emitter flow rate was 1 L / h. The irrigation rate (W) was arranged in the sub-plot. The single irrigation rate of 16 L per plant had been achieved in the fertilization bucket. Additional drip irrigation water supply pipes were laid in each treatment of the sub-plot, and the pipe water supply was controlled by an intelligent constant pressure water supply device to make the single irrigation rate of the seedlings at 3 levels: low water W1 (16 + 0 L / plant), medium water W2 (16 + 8 L / plant), and high water W3 (16 + 16 L / plant), that is, the number of steady-flow drip emitters equipped for each seedling on the corresponding water supply pipes at each level was 0, 2, and 4, and the single drip emitter flow rate was 1 L / h. To test the effect of drip irrigation and fertilization integration treatment, a traditional irrigation and fertilization treatment was set as parallel control 1 (Control1), and a treatment of only drip irrigation without fertilization was set as parallel control 2 (Control2), as shown in Table 1.

[0040] Table 1 Water and fertilizer treatment combinations for Pinus sylvestris

[0041]

[0042] For parallel control 1, Stanley compound fertilizer (N: P2O5: K2O = 19: 19: 19) was used. According to the amount of N, P, and K contained in the fertilizer amount (50g / plant) of water-soluble compound fertilizer (N: P2O5: K2O = 20: 20: 20), the amount of Stanley compound fertilizer applied was calculated, which was equivalent to 53g of fertilizer per application. Each time the fertilizer was applied, it was evenly applied in four directions at a depth of 20cm in the soil layer outside the root of Pinus sylvestris var. mongolica. After the fertilizer was applied, 24L of water was poured into the tree pool in batches using a bucket. A total of 12 seedlings were included in parallel control 1.

[0043] For parallel control 2, drip irrigation pipes were laid and drip irrigation was used to water Pinus sylvestris. The water output was controlled by intelligent constant pressure water supply equipment. Each seedling was equipped with 6 steady flow drip arrows with a flow rate of 1L / h. The single irrigation volume of a single seedling was 24L, which was the same as the irrigation volume (W2) in the water-fertilizer integration. There were a total of 12 seedlings in parallel control 2.

[0044] On August 22, 2022, the drip irrigation and fertilizer integration test was started, once every 7 days, for a total of 10 fertilizations, each time for 4 hours from 7:00 to 11:00 on a sunny day. The fertilizer solution was prepared in advance for the integrated water and fertilizer treatment, and the fertilizer bucket and booster pump switch were turned on at 7:00 for drip irrigation and fertilization. The intelligent constant pressure water supply controller was turned on simultaneously to supply water to the integrated water and fertilizer replenishment pipeline and the pipeline for drip irrigation without fertilization. Conventional irrigation and fertilization treatment buried fertilizers in advance, and 24L of water was poured into the tree hole in batches with buckets between 7:00 and 11:00. The time of each treatment was synchronized.

[0045] The current year leaves of the third whorl of branches from top to bottom of a 9-year-old Scots pine were selected as test samples, and samples were taken from the four directions of southeast, northwest, and northeast. Leaf sampling was carried out on December 24, 2022 to determine the physiological indicators of Scots pine leaves in winter. Before measuring each indicator, the leaves must be rinsed with distilled water and wrapped with absorbent paper to absorb the moisture attached to the needles.

[0046] 1. Determination of relative conductivity

[0047] Relative conductivity is the most direct physiological indicator to characterize the damage of leaf low temperature stress. The higher the relative conductivity, the more serious the damage.

[0048] The obtained Pinus sylvestris leaves were rinsed with distilled water, and the water on the leaves was absorbed by wrapping with absorbent paper. 1g of leaves were weighed for each plot, cut into 1mm small segments, placed in a clean test tube, and 20mL of deionized water was added. The extract was soaked in a constant temperature water bath at 20℃ for 1d, and shaken at irregular intervals. The conductivity C1 of the extract was measured using a DDS-11A conductivity meter, and then each sample was boiled in water for 15min, cooled to room temperature and shaken, and the conductivity C2 after all cells were destroyed was measured. The calculation formula is:

[0049] Relative conductivity (%) = C1 ÷ C2 × 100% (1)

[0050] Through split-plot experiment variance analysis, it is known that the fertilization rate has a significant effect on the relative conductivity of Pinus sylvestris var. mongolica leaves under natural winter conditions (p < 0.05).

[0051] With the increase of the fertilization rate, the relative conductivity of Pinus sylvestris var. mongolica leaves under low-fertilizer treatment is significantly lower than that under medium-fertilizer and high-fertilizer treatments (p < 0.05):

[0052] The relative conductivities of the three fertilization levels are 24.31%, 30.77%, and 31.98% in sequence;

[0053] The MDA contents of the three fertilization levels are 113.14 nmol / gDW, 120.17 nmol / gDW, and 125.57 nmol / gDW in sequence;

[0054] Under low-fertilizer treatment, the relative conductivity is the lowest, the MDA content is the lowest, and the cold resistance performance is the best.

[0055] See Figure 1 , under each integrated water and fertilizer treatment, the relative conductivity of the leaves is significantly lower than that of the conventional irrigation and fertilization treatment and the treatment of only drip irrigation without fertilization. The performance of the low-fertilizer treatment is the most prominent, indicating that the low-fertilizer amount has the most obvious effect on improving the cold resistance of winter leaves. The relative conductivities of the conventional treatment and the only drip irrigation treatment are close, and there is no significant difference. Figure 1 The data in are mean ± standard deviation. * and ** indicate that there are significant differences between drip irrigation integrated with water and fertilizer and traditional irrigation and fertilization methods (parallel control 1) at the p < 0.05 and p < 0.01 levels, and (+) and (++) indicate that there are significant differences between drip irrigation integrated with water and fertilizer and the method of only drip irrigation without fertilization (parallel control 2) at the p < 0.05 and p < 0.01 levels. Figure 2 and Figure 3 The same as this.

[0056] 2. Determination of superoxide dismutase (SOD) activity

[0057] Superoxide dismutase (SOD) can scavenge the reactive oxygen species induced by low temperature and reduce the oxidative stress damage of leaves.

[0058] Superoxide Dismutase (SOD) Activity Assay Kit (Solarbio, China). Determination by visible spectrophotometry. Weigh 0.1 g of fresh needles of Pinus sylvestris var. mongolica in each plot, add 1 mL of SOD extraction solution and grind. Transfer to an EP tube and place in an ice bath. Centrifuge at 8000 g for 10 min (4 °C). Keep the supernatant on ice for further measurement. Prepare the assay tubes, control tubes, blank tubes 1 and 2 according to the instructions. After thorough mixing, incubate in a water bath for 30 min (37 °C). Measure the absorbance at 560 nm in a 1 mL quartz cuvette. Calculate: ΔA blank = A blank 1 - A blank 2, ΔA assay = A assay - A control. According to the instruction manual, the SOD activity calculation formula is:

[0059] Inhibition percentage (%) = (ΔA blank - ΔA assay) ÷ ΔA blank × 100% (2)

[0060] SOD activity (U / gDW) = 11.11 × inhibition percentage ÷ (1 - inhibition percentage) × F ÷ DW (3)

[0061] The antioxidant enzyme activities of the needles of Pinus sylvestris var. mongolica under natural winter conditions were measured. It was found that the fertilization rate had a significant effect on the SOD activity of the needles of Pinus sylvestris var. mongolica (p < 0.05).

[0062] See Figure 2 , with the increase of the fertilization rate, the SOD activity of the needles of Pinus sylvestris var. mongolica in winter showed a significant decreasing trend (p < 0.05). The SOD activities at the three fertilization levels were 639.14 U / gDW, 453.1 U / gDW, and 259.73 U / gDW in sequence. The SOD of the needles was the highest under the low-fertilizer treatment and had stronger cold resistance.

[0063] 3. Determination of photosynthetic pigments

[0064] The photosynthetic pigment content of the needles of Pinus sylvestris var. mongolica was determined by acetone extraction method. Weigh 0.2 g of fresh needles in each plot, cut into 1 mm segments and put into a screw-cap tube. Add 80% acetone solution to make the volume up to 15 mL. Tighten the screw-cap of the tube and place in the dark for extraction for 2 d. Measure the absorbance when the needles turn grayish white. Measure the absorbance of chlorophyll a at a wavelength of 663 nm, the absorbance of chlorophyll b at a wavelength of 645 nm, and the absorbance of carotenoids at a wavelength of 470 nm. Calculate by the following methods:

[0065] Ca = 12.21A663 - 2.59A636 (4)

[0066] Cb = 20.31A646 - 5.03A663 (5)

[0067] Cx·c = (100A470 - 3.27Ca - 104Cb) ÷ 229 (6)

[0068] Content of photosynthetic pigment (mg / g DW) = C × V × F ÷ DW ÷ 1000 (7)

[0069] Wherein:

[0070] Ca — Chlorophyll a concentration (mg / L); Cb — Chlorophyll b concentration (mg / L); Cx·c — Carotenoid concentration (mg / L); V — Total volume of extraction solution (mL).

[0071] The photosynthetic characteristics of plants can, to a certain extent, reflect the strength of plant stress resistance. Affected by the low temperature in winter, the light energy conversion efficiency of chloroplasts in the leaves of Pinus sylvestris var. mongolica significantly decreases, resulting in excessive excitation energy, generating reactive oxygen species, and causing oxidative stress damage to the leaves. In addition to the above antioxidant enzymes that can scavenge reactive oxygen species, photoprotective pigments also play an important role in quenching excitation energy. As an important photoprotective pigment, carotenoids can be used as an effective indicator of the winter cold resistance of leaves. Through split-plot experiment variance analysis, it is known that the fertilization rate has a significant effect on the carotenoid content in winter leaves (p<0.05).

[0072] Generally, the chlorophyll content in the leaves of Pinus sylvestris var. mongolica in winter is about 1 / 4 of that in the growth season, the carotenoid content is about 2 times that in the growth season, and the ratio of carotenoids to chlorophyll in winter is about 8 times that in the growth season. This is an adaptive mechanism of Pinus sylvestris var. mongolica to low temperature in winter. Figure 3 The results show that the fertilization rate has a significant effect on the carotenoid content in leaves (p<0.05). With the increase of the fertilization rate, the carotenoid content significantly decreases.

[0073] See Figure 4 , the chlorophyll content in the leaves of Pinus sylvestris var. mongolica under the integrated water and fertilizer treatment is higher than that under the conventional irrigation and fertilization treatment and the treatment of only drip irrigation without fertilization. Among them, each integrated water and fertilizer treatment at low and medium fertilizer levels shows significant advantages (p<0.05). Affected by low temperature, chlorophyll degrades, the progress of photosynthesis is restricted, and various life activities are at a relatively low physiological level. Compared with the growth season, the chlorophyll content in each integrated water and fertilizer treatment in winter significantly decreases, but the attenuation amplitude of chlorophyll in Pinus sylvestris var. mongolica under the integrated water and fertilizer treatment is lower than that of the 2 parallel controls. In the integrated water and fertilizer treatment, the attenuation amplitude of chlorophyll under low and medium fertilizer treatments is lower than that under high fertilizer treatment, maintaining a relatively high chlorophyll content. This plays an important role in reducing leaf chlorosis in winter and improving the winter landscape effect of Pinus sylvestris var. mongolica.

[0074] Figure 5 are the winter Pinus sylvestris var. mongolica leaf diagrams of three treatments. a is the treatment of the present invention, b is the traditional irrigation and fertilization treatment, and c is the treatment of only drip irrigation without fertilization. The winter Pinus sylvestris var. mongolica leaf diagram of the treatment of the present invention is greener, and the grayscale picture shows a darker color.

[0075] The above are only the preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. For those of ordinary skill in the art, without departing from the spirit and scope of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. A method for increasing the greening and cold resistance of Pinus sylvestris var. mongolica in winter, characterized in that, Use the integrated water and fertilizer system to drip-irrigate and fertilize Pinus sylvestris var. mongolica. Before the dormancy period, 1 to 3 months in advance, fertilize at 1 / 3 to 1 / 2 of the single recommended fertilization amount of 75 g / plant during the rapid growth period, and drip-irrigate at 2 / 3 to 4 / 5 of the single recommended irrigation amount of 32 L / plant during the rapid growth period. Use water-soluble compound fertilizer with N∶P2O5∶K2O = 20∶20∶20 for fertilization. Drip-irrigate water and fertilizer once every 7 to 8 days, for a total of 9 to 10 times, and each drip-irrigation lasts for 3 to 5 hours.

2. The method for increasing the greening and improving the cold resistance of Pinus sylvestris var. mongolica in winter according to claim 1, wherein Before the dormancy period, 2 to 3 months in advance, fertilize at 1 / 3 of the single recommended fertilization amount during the rapid growth period, and drip-irrigate at 3 / 4 of the single recommended irrigation amount during the rapid growth period.

3. The method for increasing the greening and cold resistance of Pinus sylvestris var. mongolica in winter according to claim 1, characterized in that, The Pinus sylvestris var. mongolica is a 9-year-old Pinus sylvestris var. mongolica.

4. The method for increasing the greening and cold resistance of Pinus sylvestris var. mongolica in winter according to claim 3, characterized in that The Pinus sylvestris var. mongolica is a large-scale container transplanting seedling of 9-year-old Pinus sylvestris var. mongolica that has been cultivated in the ground container for 1 year.

5. The method for increasing the greening and improving the cold resistance of Pinus sylvestris var. mongolica in winter according to any one of claims 1 to 4, characterized in that Before the dormancy period, 1 to 3 months in advance, drip-irrigate 16 L / plant·time of water and 25 g / plant·time of water-soluble compound fertilizer to the roots of Pinus sylvestris var. mongolica.

6. The method for increasing the greening and improving the cold resistance of Pinus sylvestris var. mongolica in winter according to claim 5, characterized in that, The method is applied to the semi-arid continental monsoon climate region.

7. The method for increasing the greening and improving the cold resistance of Pinus sylvestris var. mongolica in winter according to claim 1, characterized in that The recommended fertilization amount and recommended irrigation amount are scientifically judged according to the phenological conditions, as well as the new shoot growth amount, ground diameter growth amount, starch content, soluble sugar content, and promotion results of photosynthetic pigments of Pinus sylvestris var. mongolica under fertilization conditions.

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