A method for compound planting of ferns based on birch forest

Abstract

The present application provides a kind of fern composite planting method based on birch forest, and belongs to the technical field of agricultural planting.The present application provides a kind of fern composite planting method based on birch forest in the low-quality birch forest area in northeast forest, solves the problem of low utilization rate of existing low-quality birch forest interspace and unbalanced supply and demand of fern market, and solves the problem of fern resource cultivation and artificial large-area planting difficulty.The present application solves the problem of low-quality birch forest space utilization difficulty by different forest type selection method and different canopy density fern planting method, realizes the one-year two-season harvesting mode of spring vegetable picking and autumn fruit picking by low canopy density plot black bud currant and fern intercropping, increases the utilization efficiency and multiple cropping index of interspace in forest, and provides a new mode for forest economy development and lays a foundation for forest fern industry development.

Description

Technical Field

[0001] This invention belongs to the field of agricultural planting technology, particularly the cultivation technology of understory crops. Background Technology

[0002] Large areas of birch forests are distributed in low-lying wetlands below 1000m altitude in the Greater Khingan Mountains, Lesser Khingan Mountains, and Changbai Mountains of Northeast China. Due to low soil temperature and acidity, these birch forests have low canopy closure and low plant diversity. Large areas of bare open spaces are only covered with a few shrubs and herbaceous plants such as sedges, honeysuckle, and crown of thorns, resulting in low species diversity, low yield, and low quality of natural forest products. Furthermore, due to the strong sprouting ability and short lifespan of birch forests, natural regeneration is rapid. In reality, some birch forests in natural forest areas suffer from aging trees, poor timber quality, and slow growth, resulting in very low economic benefits. These birch forests are generally referred to as low-quality birch forests. For these low-quality birch forests, how to utilize the large open spaces within them to improve land utilization and create greater economic benefits, while protecting the natural ecology of the natural forests, is an urgent problem that needs to be solved by those skilled in the art.

[0003] Blackcurrant is a shrub, about 1 meter tall, producing black berries. The main producing areas are in Northern Europe, with major producing countries and regions including Poland, Russia, Germany, the Czech Republic, the United Kingdom, and Scandinavia. In 1998, the world's total production reached 601,519 tons. In my country, blackcurrant is mainly grown in Heilongjiang, Jilin, Liaoning, and Xinjiang. In Europe, blackcurrant has long been an important raw material for juice production. It is also used in the production of jams, jellies, liqueurs, dairy products, and as a flavoring or coloring agent for fruit wines.

[0004] Ferns, including bracken fern (Pteridium aquilinum L.), wild fern (Osmunda cinnamomea L.), monkey leg fern (Athyrium multidentatum), and cucumber fern (Matteuccia struthiopteris L.), are collectively known as ferns due to their similar morphology. Ferns are nutritious, healthy, and safe wild vegetables, making them a truly ideal choice for understory cultivation and the most representative forest vegetables of Northeast China. While their reserves are relatively large, wild resources are scattered, limiting harvestable quantities and hindering commercial development. Furthermore, as ferns belong to lower plant groups and reproduce via spores, their self-regeneration ability is poor. Under natural conditions, they primarily reproduce via rhizomes, resulting in a slow reproduction rate and posing challenges to resource conservation and production. Therefore, a cultivation method is urgently needed to alleviate the pressure on existing demand for ferns. Summary of the Invention

[0005] This invention provides a fern intercropping model for low-quality birch forests in Northeast China, which solves the problems of low utilization rate of open space in existing low-quality birch forests and the imbalance between supply and demand in the fern harvesting market. It also solves the problems of fern resource tending and large-scale artificial planting difficulties.

[0006] A method for intercropping ferns in birch forests involves planting ferns monoculture or intercropping ferns and blackcurrants in birch forests with a canopy closure of less than 0.6.

[0007] Before the intercropping, the land is prepared and weeds are removed.

[0008] The land preparation involves clearing shrubs and weeds with a diameter of less than 5 cm before the first snowfall in winter, and then clearing dry grass on the ground surface and small shrubs with a trunk base of less than 5 cm and their roots in mid-to-late April of the following year.

[0009] The weeding was carried out using a herbicide, namely 33% chlorpyrifos EC at a dilution of 300 times, with a dosage of 200 ml per mu, or 5% quizalofop-P-ethyl EC at a dilution of 1500 times, with a dosage of 50 ml per mu.

[0010] The ferns mentioned are fern, bracken fern, cucumber fern, or fern fern.

[0011] When the canopy closure is 0.5, ferns are used as a monoculture in a mixed planting.

[0012] When the canopy closure is 0.3, intercropping of ferns and blackcurrants is adopted for compound planting.

[0013] The blackcurrants are planted in early to mid-May, at a density of 1m × 1.5m.

[0014] The ferns are planted from mid-May to early June, with a planting density of 0.4m × 1.5m per plant.

[0015] The intercropping consists of alternating rows of blackcurrants and ferns.

[0016] Beneficial effects

[0017] 1. This invention, for the first time, utilizes the shade-tolerant and moisture-loving characteristics of ferns, and fully leverages the low canopy density, humidity, and open spaces within low-quality birch forests to construct a composite model of low-quality birch forests and ferns. This method provides a model for the protection and industrial development of understory fern resources in the forest areas of Northeast China.

[0018] 2. This invention not only solves the problem of space utilization difficulties in low-quality birch forests by selecting different forest types and planting ferns under forests with different canopy closures, but also achieves a two-season harvest method of spring vegetable harvesting and autumn fruit harvesting by intercropping blackcurrant with ferns in low canopy closure plots. This increases the utilization efficiency and multiple cropping index of open spaces in the forest, and also provides a new model for the development of understory economy and lays the foundation for the industrialization of fern cultivation in forest areas.

[0019] 3. Developing an integrated planting model for ferns under forest cover will play an important role in alleviating the pressure of existing demand for wild ferns and promoting the development of the under-forest economy. At the same time, conducting research on artificial cultivation under forest cover will transform the process of harvesting from the mountains into planting and nurturing the mountains, thereby increasing the resource reserves, harvesting volume, and commercial volume of edible ferns, improving economic, social, and ecological benefits, and achieving the protection and efficient utilization of wild fern resources. Attached Figure Description

[0020] Figure 1 The results show the effects of different canopy closures on the survival rate of planted ferns.

[0021] Figure 2 The results of intercropping blackcurrant with wild ferns on the relative water content and specific area of ​​wild fern leaves.

[0022] Figure 3 This study compares the yield of bracken fern grown naturally in natural forests with the yield after artificial planting and targeted tending. Detailed Implementation

[0023] Example 1. Fern seedling planting and composite pattern construction.

[0024] 1. Forest type selection

[0025] In the Northeast forest region, low-quality birch forests, birch / oak mixed forests, and moist but non-waterlogged areas at forest edges with a canopy closure of less than 0.6 have soils rich in organic matter and a pH of around 5.5. The optimal canopy closure is around 0.4-0.5.

[0026] 2. Land preparation and setup before planting

[0027] After selecting a suitable site, clear away shrubs and weeds such as crown of thorns, lilac, and azalea with a diameter of less than 5 cm before the winter snow. In the spring of the following year, after the snow melts, manually remove the dry grass on the ground and small shrubs with a trunk base of less than 5 cm and their roots in mid-to-late April.

[0028] For pre-planting herbicides, apply soil treatment 15 days before seedling emergence. The most effective and safe herbicides are achieved with a 300-fold dilution of 33% chlorpyrifos EC at a rate of 200 ml per acre; alternatively, use a 1500-fold dilution of 5% quizalofop-P-ethyl EC at a rate of 50 ml per acre.

[0029] 3. Preparation of fern seedlings

[0030] Seedlings are prepared using spore propagation or tissue culture. After being hardened or acclimatized, one-year-old spore seedlings or tissue-cultured leaf-expanding seedlings are transplanted into seedling trays and left to be transplanted in the second year.

[0031] 4. Fern seedling planting and composite planting pattern construction

[0032] (1) In forest plots with a canopy closure of less than 0.3, intercropping of ferns and blackcurrants is adopted for planting. In mid-May, blackcurrants are planted at a density of 1m×1.5m. One-year-old blackcurrant cuttings are planted in pairs per hole, and two-year-old or older seedlings are planted in one hole per hole. From mid-May to early June, two- to three-year-old fern seedlings are planted at a spacing of 0.4m×1.5m. Holes about 15cm deep are dug, with the fern seedlings exposed, and then watered thoroughly and covered with soil. The planting method is as shown in Table 1.

[0033] Table 1. Land Parcel Configuration with Canopy Closure Below 0.3

[0034] ⊙ ～ ⊙ ＊ ⊙ □ ⊙ ● ⊙ ～ ⊙ ＊ ⊙ □ ⊙ ● ⊙ ～ ⊙ ＊ ⊙ □ ⊙ ● ⊙ ～ ⊙ ＊ ⊙ □ ⊙ ●

[0035] Legend: ⊙: Blackcurrant; ~: Bracken; *: Wild ferns; □: Monkey's foot fern; ●: Cucumber fragrance

[0036] (2) For plots with a canopy density of 0.6-0.3, plant at a spacing of 0.4m×1m, dig holes about 15cm deep, expose the heart leaves of the fern seedlings, water thoroughly, and cover with soil. The arrangement is shown in Table 2.

[0037] Table 2. Land parcel configuration with canopy density between 0.6 and 0.3.

[0038]

[0039] Note: a, b, c, and d represent fern, bracken, cucumber fern, and wild fern, respectively.

[0040] 5. Post-natal care and management

[0041] After the first year of transplanting and survival, spray the leaves with a 1000-1500 times dilution of potassium dihydrogen phosphate; after an interval of 7 days, spray with a 0.5%-1% concentration of urea, 2-3 times is appropriate.

[0042] In early July, remove newly sprouted weeds and shrubs. For plots with abundant weeds, a second round of weeding can be done in early to mid-August. Two years later, some shrubs will still grow in the cultivated plots; these should be removed before they sprout the following year. Subsequent weeds and shrub sprouts should also be removed multiple times. Alternatively, after removing weeds and shrubs, sow barnyard grass and promptly harvest the mature barnyard grass spikes (seeds) and stalks for fodder. Sowing barnyard grass is most effective, likely because barnyard grass grows rapidly in its first year, causing other herbaceous plants to decline completely in competition, allowing the bracken community to recover quickly in the second year without barnyard grass.

[0043] Harvesting begins in the third year. The first harvest ends in mid-June to ensure sufficient growth of the ferns, after which harvesting can be done every other year. Harvesting is best done before the pinnate leaflets unfold, when the ferns are still "fist-shaped" and the stems are 20-25 cm tall. Harvesting too early results in weak ferns, affecting their market quality; harvesting too late results in overripe ferns that are inedible.

[0044] In the third spring, the fern sprouts are harvested from one side, leaving 2-3 sprouts on the other side for continued growth. This not only yields the sprouts but also promotes root renewal and root sucker growth.

[0045] At the same time, weeding and cultivation should be strengthened. During the management process, the cut weeds and shrub branches should be evenly placed in the forest clearings. This will not only improve the soil organic matter, but also inhibit weed regeneration and retain soil moisture, thereby enhancing the competitiveness of bracken growth and ultimately forming a vegetation type dominated by bracken.

[0046] To obtain high-quality, robust, and high-yield wild ferns, fertilization should be carried out according to the harvest yield. Generally, organic fertilizer should be applied once every other year, with 2000-3000 kg of high-quality, well-rotted manure per hectare. The best time for fertilization is from the beginning of winter to the time when motor vehicles can travel on low-lying wetlands before the snow melts in spring.

[0047] Example 2. Effects of different canopy closures on the survival and growth of ferns.

[0048] The implementation site for this embodiment is the "Heilongjiang Provincial Cold-Temperature Plant Germplasm Resource Conservation Field Scientific Observation and Research Station" (51°24′18.19″N; 126°41′47.49″E, altitude 288M) located in Sanka Forest Farm, Huma County, Heilongjiang Province. The terrain is relatively flat, and the climate is cold-temperate continental, with a frost-free period of about 110 days per year. The forest farm's operational area covers 10,000 hectares, of which 1,000 hectares are birch forest. The main tree vegetation at the implementation site is low-quality pure birch forest, with mixed birch / larch / oak forests at the edges. The shrub layer mainly consists of honeysuckle, marsh willow, rhododendron, and crown of thorns, while the herbaceous layer mainly consists of sedge, monkey's foot fern, bracken, and cucumber fragrance.

[0049] Five treatments were set up in the forest clearings: low canopy closure (0.3), medium canopy closure (0.4 and 0.5), and high canopy closure (0.6 and above). Each plot was 10m × 10m and a randomized block design was used with three replicates. The survival rate of two-year-old seedlings of four fern species—Pteridium aquilinum L., Osmunda cinnamomea L., Athyrium multidentatum, and Matteuccia truthiopteris L.—was investigated 15 days after transplanting. Growth and yield per unit area were investigated 30 and 60 days after transplanting to assess the optimal canopy closure for planting.

[0050] like Figure 1 As shown, the survival rate of *Athyrium multidentatum* was the highest when planted under forest cover, followed by *Matteuccia struthiopteris* L., with *Osmunda cinnamomea* L. and *Pteridiumaquilinum* L. decreasing in that order. Specifically, when the canopy closure decreased from 0.3 to 0.5, the survival rate of fern seedlings increased significantly, but the difference was not statistically significant; when the canopy closure increased to above 0.5, the survival rate of fern seedlings decreased significantly. Therefore, a forest canopy closure of 0.5 is a key threshold affecting the survival rate of fern seedlings.

[0051] The effects of different canopy closures on the growth and yield of bracken seedlings were measured on June 15th and July 15th, as shown in Table 3. When the canopy closure was 0.3, the number of root tillers of bracken at different time points was significantly higher than that of plots with canopy closures of 0.5 and 0.7. At the same time, the number of root tillers decreased significantly with increasing canopy closure. This may be because bracken prefers light, and light directly affects the increase of soil temperature and the reproduction of root tillers. For fern, monkey leg fern, and cucumber fern, the number of root tillers did not differ significantly at canopy closures of 0.3 and 0.5, but was significantly higher than that at canopy closure of 0.7. When the canopy closure was 0.3 and 0.5, the plant height, aboveground biomass, and other indicators of bracken, fern, monkey leg fern, and cucumber fern were significantly higher than those at canopy closure of 0.7, but there was no significant difference between canopy closures of 0.3 and 0.5. At the same time, the biomass of monkey leg fern was the highest at different time points, followed by fern, cucumber fern, and bracken. Therefore, a canopy closure of less than 0.5 is suitable for planting the above four types of ferns, with monkey leg fern and bracken fern having the highest relative yields.

[0052] Table 3. Effects of different canopy closure levels on fern seedling growth and yield.

[0053]

[0054] Note: Lowercase letters a and b indicate a significance level of p ≤ 0.05.

[0055] Example 2

[0056] In this embodiment, the effects of intercropping blackcurrant with ferns (with a forest canopy density below 0.3) on the relative water content and specific leaf area of ​​ferns are as follows: Figure 2 As shown in the figure, leaf water content and specific leaf area index are key parameters affecting the taste and quality of wild ferns. Excessive sunlight can also reduce the leaf expansion time of young leaves and shorten the harvest cycle, directly impacting the economic benefits of cultivation. Therefore, to fully utilize forest clearings with low canopy closure (below 0.3) and improve the commercial quality of wild ferns, we intercropped them with *Centipeda minima*, a plant that prefers moisture but is not shade-tolerant, taking advantage of their moisture-loving and shade-tolerant characteristics. Simultaneously, we used wild fern monoculture as a control and measured the relative leaf water content and specific leaf area index of the wild ferns.

[0057] The experiment was conducted in the second year after planting, around May 20th, during the fern harvest season. Five leaves were collected from each plant, and the leaf area (LA) was calculated using a leaf scanner. The fresh weight (FW) was also measured, and the leaves were placed in distilled water for 8 hours. The total weight (TW) was then measured. The leaves were then placed in a paper bag and dried at 105°C for 30 minutes, followed by drying at 80°C to constant weight. The dry weight (DW) was recorded.

[0058]

[0059] Leaf area index = LA / DW (2)

[0060] The results are as follows Figure 2 As shown, in Figure 2 (a) Intercropping bracken with blackcurrant had no significant effect on the relative water content of leaves, but... Figure 2 (b) The leaf area ratio was significantly affected, which may be because bracken fern is more light-loving and relatively drought-tolerant compared to other ferns. After intercropping, the leaves increased in size to increase photosynthetic efficiency. After intercropping bracken fern, cucumber fern, and blackcurrant, the relative water content of the leaves increased significantly compared to monoculture, but the leaf area ratio did not change significantly. This may be related to the fact that bracken fern and cucumber fern are more moisture-loving and shade-tolerant, and their larger leaves have a stronger ability to capture light. After intercropping monkey leg fern and blackcurrant, the relative water content and leaf area of ​​the leaves increased significantly. This may be related to the fact that monkey leg fern's native habitat is a low-humidity environment, and its leaves are relatively small and highly sensitive to light. Intercropping forces the leaves to strengthen their ability to capture light, thereby promoting water absorption.

[0061] Example 3

[0062] This example is an economic benefit analysis. Harvesting took place three years after planting, with five leaves collected from each plant. Actual measurements are shown in Table 4. The average yields of bracken fern and monkey's foot fern monoculture at canopy closure below 0.3 were 180 kg / mu and 265 kg / mu, respectively, significantly lower than the average yields of 210 kg / mu and 290 kg / mu when intercropped with blackcurrant. The average yields of bracken fern and cucumber fern monoculture were 290 kg / mu and 280 kg / mu, respectively, lower than the average yields of 320 kg / mu and 310 kg / mu when intercropped with blackcurrant, but the differences were not significant. At a canopy closure of 0.5, the average yields of bracken fern, bracken fern, monkey's foot fern, and cucumber fern were 240 kg / mu, 380 kg / mu, 310 kg / mu, and 360 kg / mu, respectively, significantly higher than the yields at canopy closures below 0.7 and 0.3. Meanwhile, intercropping blackcurrant in areas with a canopy closure of less than 0.3 also yields fruit profits. If all wild ferns are priced at 5 yuan / kg and blackcurrant at 6 yuan / kg, the profit per mu (unit of land area) from intercropping wild ferns with blackcurrant is 210 × 5 yuan / kg + 245 × 6 yuan / kg = 2520 yuan / mu. The profit from *Gnaphalium affine* is 3070 yuan / mu, *Fernonia acutissima* is 2920 yuan / mu, and *Fragranceia scabra* is 3020 yuan / mu. Therefore, intercropping in areas with a low canopy closure of less than 0.3 yields the greatest economic benefits. Since blackcurrant prefers sunlight, it can maintain growth but will not bear fruit or will produce very little fruit at a canopy closure of around 0.5. Therefore, intercropping wild ferns in areas with a canopy closure of 0.5 is the most suitable and yields the highest. We adopt different planting patterns according to different canopy closures to maximize the use of forest open spaces while achieving the greatest economic and ecological benefits.

[0063] Table 4. Comparison of yields under different canopy closures and planting patterns three years after transplanting.

[0064] Canopy density and planting patterns Bracken fern (kg / mu) Bracken fern (kg / mu) Monkey's leg fern (kg / mu) Cucumber fragrance (kg / mu) Blackcurrant (kg / mu) 0.3 single work 180±8c 290±12b 265±16b 280±21b - 0.3 intercropping 210±11b 320±21b 290±18a 310±28b 245±24 0.5 single work 240±13a 380±7a 310±10a 360±17a - 0.7 single work 154±18d 126±32c 142±25c 133±19c -

[0065] Note: Different lowercase letters a, b, c, d indicate a significance level of p≤0.05.

[0066] like Figure 3 As shown, when the original habitats of ferns were replanted and nurtured using the methods described above, the intercropping pattern of ferns and blackcurrants under a canopy closure of 0.3 showed a 209% increase in yield per mu (667 square meters) for ferns, a 323.7% increase for bracken fern, a 289.7% increase for clematis, and a 310.8% increase for citrus aurantiaca under a canopy closure of 0.5 compared to the natural state. Under a canopy closure of 0.5, the same yield patterns showed a 239% increase in yield per mu for ferns, a 379% increase for bracken fern, a 309% increase for clematis, and a 359% increase for citrus aurantiaca. Therefore, this method of nurturing natural plots not only provides a good demonstration for the production and quality improvement of ferns in low-quality birch forests in Northeast China, but also offers a new approach to developing understory economy.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for intercropping ferns in birch forests, characterized in that, The method involves intercropping birch forests with a canopy closure of less than 0.6, based on the canopy closure of the birch forest: when the canopy closure is 0.5, ferns are used as a monoculture in the intercropping; when the canopy closure is 0.3, ferns and blackcurrants are used as intercropping in the intercropping.

2. The method according to claim 1, characterized in that, Before the intercropping, the land is prepared and weeds are removed.

3. The method according to claim 2, characterized in that, The land preparation involves clearing shrubs and weeds with a diameter of less than 5 cm before the first snowfall in winter, and then clearing dry grass on the ground surface and small shrubs with a trunk base of less than 5 cm and their roots in mid-to-late April of the following year.

4. The method according to claim 2, characterized in that, The weeding was carried out using a herbicide, namely 33% chlorpyrifos EC at a dilution of 300 times, with a dosage of 200 ml per mu, or 5% quizalofop-P-ethyl EC at a dilution of 1500 times, with a dosage of 50 ml per mu.

5. The method according to claim 1, characterized in that, The ferns mentioned are fern, bracken fern, cucumber fern, or fern fern.

6. The method according to claim 1, characterized in that, The blackcurrants are planted in early to mid-May, at a density of 1m × 1.5m.

7. The method according to claim 1, characterized in that, The ferns are planted from mid-May to early June, with a planting density of 0.4m × 1.5m per plant.

8. The method according to claim 1, characterized in that, The intercropping of ferns and blackcurrants is carried out by alternating rows of blackcurrants and ferns.

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