Compound planting method for eucalyptus and paper mulberry

Abstract

The invention discloses a compound planting method for eucalyptus and paper mulberry, and belongs to the technical field of plant planting. The method comprises the following technical steps: (1) forest land preparation; (2) afforestation and interplanting; (3) tending management; (4) harvesting and utilizing the paper mulberry. According to the method, good economic, ecological and social benefits are obtained through compound interplanting of the eucalyptus and the paper mulberry, rational close planting, precise fertilization and the like. According to the method, the light energy utilization rate and the forest space utilization rate can be increased, soil fertility is increased, healthy growth of eucalyptus and paper mulberry is promoted, ecological compensation is promoted, and sustainable and healthy development of the eucalyptus forest industry is effectively promoted.

Description

Technical Field

[0001] This invention belongs to the field of plant cultivation technology, specifically relating to a method for intercropping eucalyptus and paper mulberry. Background Technology

[0002] Eucalyptus, an evergreen tree belonging to the genus Eucalyptus in the family Myrtaceae, is native to Australia. It is a major raw material species for industrial papermaking and has been widely introduced to my country due to its rapid growth, high yield, low susceptibility to pests and diseases, strong adaptability, wide range of uses, and high economic value. Eucalyptus forests have played a significant role in increasing carbon sequestration, promoting integrated wood-pulp-paper production, and addressing climate change. However, the long-term large-scale management of pure eucalyptus plantations and multi-generational continuous planting have led to many problems, such as ecological damage, reduced biodiversity, water resource depletion, and soil degradation. Therefore, the health and sustainable development of eucalyptus plantations have been severely affected.

[0003] Paper mulberry ( Broussonetia papyrifera Paper mulberry (Broussonetia papyrifera), also known as the paper mulberry or mulberry tree, is a deciduous tree belonging to the genus Broussonetia in the family Moraceae. It is widely distributed throughout my country, growing in plains, hills, and mountains. It is a fast-growing, high-yielding, short-rotation, and highly adaptable native tree species. Paper mulberry leaves are rich in protein, making them excellent livestock feed. The protein content of paper mulberry leaves is as high as 20-30%, with crude protein levels three times that of rice and corn, and twice that of wheat. They are also rich in amino acids, vitamins, carbohydrates, and trace elements. After scientific processing, they become a green feed with significant economic, social, and ecological value. The paper mulberry has a well-developed root system, and its rhizobia have nitrogen-fixing properties, increasing soil nitrogen content, improving soil fertility, and mitigating the destructive impact of eucalyptus trees on the soil. It has a significant effect on soil improvement, making it an excellent crop for both forage and ecological purposes. Through long-term research on the growth of paper mulberry, the inventors and their team members discovered that paper mulberry has the characteristics of being able to be harvested for many years after a single planting, having a large biomass, and being resistant to cutting. It can be harvested for the first time when it grows to 100cm, and then harvested again every time it grows to 100-150cm, with 2-4 harvests per year.

[0004] Currently, traditional paper mulberry planting suffers from problems such as unscientific management and low yield. There is a lack of research on intercropping patterns between eucalyptus and paper mulberry. The planting areas of eucalyptus and paper mulberry are relatively independent, which cannot make full use of the three-dimensional planting space and resources, resulting in a single economic and ecological benefit, and affecting the healthy development of the eucalyptus plantation industry. Summary of the Invention

[0005] To address the above problems, this invention provides a method for intercropping eucalyptus and paper mulberry trees. Through intercropping eucalyptus and paper mulberry trees, reasonable dense planting, and precise fertilization, it achieves excellent economic and ecological benefits.

[0006] This invention is achieved through the following technical solution: A method for intercropping eucalyptus and paper mulberry trees includes the following steps: (1) Forest land preparation: Select slopes ≤25 。 The planting area is a forest land with an altitude of less than 500m, deep soil (≥60cm), fertile soil and good drainage. The whole land is cultivated and prepared. Organic fertilizer is evenly spread and the soil is deeply cultivated and turned over to a depth of 25-30cm. Then, planting holes for eucalyptus and paper mulberry are dug. When digging the holes, the topsoil is placed on top of the holes and debris, stones and other objects are picked out and cleaned so that the topsoil can be put back into the holes. (2) Afforestation and intercropping: The planting period is from February to May. Eucalyptus and paper mulberry are planted at the same time. Before planting, apply base fertilizer to the planting hole and mix it evenly with the soil in the hole. When planting, remove the nutrient bag and plant it in the planting hole. The planting spacing of eucalyptus is (2-4)m × ​​(5-6)m. Plant it deeply and compact it. The root collar is 2-3cm below the ground surface. Water it thoroughly to settle the roots. Plant paper mulberry in parallel with eucalyptus between the rows of eucalyptus. The planting spacing is 1.2m × (0.55-0.7)m. Cover it with soil and water it until the moisture content is 70-80%. Through the intercropping of eucalyptus and paper mulberry, the three-dimensional space of the forest land is fully utilized and the soil fertility is improved. (3) Nurturing and Management: Eucalyptus cultivation and management: Within 1 to 2 months after eucalyptus planting, promptly replant any missing seedlings or dead trees; 3 months after planting, combine tending with weeding, soil mounding, and straightening of seedlings; within 3 years after planting, weed and loosen the soil twice a year, combined with topdressing; after eucalyptus trees grow to 2.8 to 3m in height, prune the branches below 2m, retaining the main trunk and removing the basal side branches; Paper mulberry cultivation and management: Within one week after planting, maintain the soil moisture content at 70-80% until the seedlings emerge and survive. If there are few or missing seedlings, replant them in time. Weed the paper mulberry planting area at the same time as weeding the eucalyptus planting area. Apply fertilizer 2-3 times during the paper mulberry growing season, mainly nitrogen fertilizer. (4) Harvesting and utilization of paper mulberry: The paper mulberry is harvested for the first time when it grows to 100cm. After that, it is harvested again when it grows to 100-150cm. It is harvested 2-4 times a year. The stubble height is 25-30cm each time. After the paper mulberry grows new buds again, the fertilization steps of paper mulberry in step (3) are repeated. The harvested paper mulberry is used as fodder or made into hay for later use.

[0007] Furthermore, in step (2), when the eucalyptus planting spacing is 2m×5m, three rows of paper mulberry trees are planted parallel to the eucalyptus trees in the 5m spacing between the eucalyptus trees.

[0008] Furthermore, in step (2), when the eucalyptus planting spacing is (3-4)m×6m, four rows of paper mulberry trees are planted parallel to the eucalyptus trees in the 6m spacing between the eucalyptus trees.

[0009] Furthermore, in step (2), the spacing between the rows of the paper mulberry trees is 1.2m × 0.55m or 1.2m × 0.7m.

[0010] Furthermore, in step (2), 0.8–1 kg of farmyard manure or 80–100 g of compound fertilizer is applied as base fertilizer to each eucalyptus planting hole; 0.8–1 kg of farmyard manure or 40–50 g of compound fertilizer is applied as base fertilizer to each paper mulberry planting hole. This provides sufficient nutrients for the eucalyptus and paper mulberry seedlings and accelerates their growth.

[0011] Further, in step (3), the fertilizer used for eucalyptus topdressing is composed of eucalyptus-specific fertilizer, compound microbial fertilizer, and seaweed fertilizer mixed in a weight ratio of 5-6:2-3:1. The amount of fertilizer applied per tree is 0.5-0.6 kg. A fertilizer trench is dug 30-50 cm away from the trunk, and the fertilizer is evenly spread into the trench and then covered with soil to a thickness of not less than 15 cm. The fertilizer is applied by digging the trench, allowing the roots of the eucalyptus tree to fully absorb nutrients.

[0012] Furthermore, the fertilization trench is 25-30cm long, 18-20cm wide, and 18-20cm deep.

[0013] Further, in step (3), the fertilizer for the paper mulberry topdressing is composed of urea, slow-release fertilizer, microbial inoculant fertilizer, and seaweed fertilizer mixed in a weight ratio of 6-7:1-2:0.3-0.5:1. The amount of fertilizer applied per tree is 0.15-0.2 kg. The fertilizer is evenly spread in a circular trench and covered with soil. The fertilizer has a high nitrogen content, which can promote the growth of paper mulberry branches and leaves and increase the yield of branches and leaves.

[0014] Further, in step (1), the specifications of the eucalyptus planting pit are (28~30)cm×(28~30)cm×(45~50)cm; the specifications of the paper mulberry planting pit are (23~25)cm×(23~25)cm×(18~20)cm.

[0015] Furthermore, in step (1), the amount of organic microbial fertilizer used is 250-300 kg / mu.

[0016] This invention achieves significant economic, ecological, and social benefits through intercropping eucalyptus and paper mulberry, appropriate dense planting, and precise fertilization. The principle behind this invention is as follows: (1) The interplanting of eucalyptus and paper mulberry forms a complementary spatial resource: The formation of the vertical structure can make full use of light energy and improve the overall utilization rate of light energy. This is because eucalyptus and paper mulberry utilize sunlight in layers in the vertical direction. Eucalyptus is a tall and fast-growing tree that occupies the upper space and absorbs the strong light from the upper layer for photosynthesis. Paper mulberry, as a small shrub, occupies the middle and lower space and utilizes the weaker light from the lower layer. The different depths of the root systems reduce the competition between the two for water and nutrients. Eucalyptus has a deep taproot that absorbs deep water and nutrients. Paper mulberry has a relatively shallow root system that is widely distributed and mainly utilizes the surface soil resources.

[0017] (2) The interplanting of eucalyptus and paper mulberry promotes soil improvement and nutrient cycling: the roots of paper mulberry have nitrogen-fixing function, which significantly increases the nitrogen level in the soil and improves soil fertility; fallen leaves increase the organic matter content in the soil, improve soil structure, and enhance water and fertilizer retention capacity.

[0018] (3) Interplanting eucalyptus and paper mulberry can reduce the allelopathic effects of eucalyptus: Eucalyptus litter and root exudates contain allelopathic substances that may inhibit the growth of other plants. Paper mulberry is relatively tolerant of the allelopathic effects of eucalyptus, and its presence and litter input help to dilute or decompose these allelopathic substances and improve the understory environment.

[0019] (4) Eucalyptus and paper mulberry intercropping improves the microenvironment: the canopy of paper mulberry covers the ground surface and reduces the ground temperature; the transpiration and shading effect of paper mulberry help to increase the air humidity in the forest.

[0020] (5) Reasonable dense planting further improves light energy utilization and increases paper mulberry yield and quality. If the density of eucalyptus trees is too high or the paper mulberry trees are planted too densely, the upper layer of eucalyptus trees will seriously shade the lower layer of paper mulberry trees, resulting in poor growth or even death of paper mulberry trees, and loss of nitrogen fixation, shading and feed provision functions. If the density is too low, light energy and land use will be wasted, and the yield per mu of eucalyptus and paper mulberry trees will decrease.

[0021] (6) Precision fertilization of eucalyptus and paper mulberry can not only meet the needs of high yield and quality of eucalyptus and paper mulberry, but also reduce resource waste, avoid damage to the ecological environment, and promote the development of agriculture towards high efficiency, low carbon and sustainable development.

[0022] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. This invention achieves significant economic, ecological, and social benefits through intercropping eucalyptus and paper mulberry, appropriate planting density, and precise fertilization. Compared to traditional methods of monoculture eucalyptus forests, the single-tree timber volume of eucalyptus in this invention increases by 75%; compared to traditional methods of monoculture paper mulberry forests, the average annual yield of paper mulberry in this invention increases by 51.10%. This invention improves light energy utilization, forest space utilization, and soil fertility, promotes the healthy growth of eucalyptus and paper mulberry, facilitates ecological compensation, and effectively promotes the sustainable and healthy development of the eucalyptus forest industry.

[0023] 2. This invention utilizes a three-dimensional planting model combining eucalyptus and paper mulberry trees to improve overall light energy utilization and promote plant growth. Eucalyptus and paper mulberry trees utilize sunlight in a tiered manner vertically; the taller canopy of eucalyptus absorbs the strong light from the upper layers for photosynthesis, while the relatively shorter paper mulberry utilizes the weaker light from the lower layers. Paper mulberry is relatively resistant to the allelopathic effects of eucalyptus, and its presence and litter input help dilute or decompose these allelopathic substances, improving the understory environment and increasing biodiversity.

[0024] 3. This invention scientifically and rationally plantes two plants at close density: eucalyptus is planted with a spacing of (2-4)m × ​​(5-6)m, and paper mulberry is planted parallel to the eucalyptus between the rows with a spacing of 1.2m × (0.55-0.7)m. This can further improve the light energy utilization rate and increase the yield and quality of paper mulberry, thus avoiding the waste of light energy caused by too low a density and the excessive growth and decreased photosynthetic capacity caused by too high a density.

[0025] 4. This invention achieves efficient land use by intercropping eucalyptus and paper mulberry. The two plants have different growth cycles and characteristics: eucalyptus grows slowly and has a long-term yield; paper mulberry grows relatively quickly, and after harvest, it can be used as forage or feed, generating short-term profits. Furthermore, the well-developed root system of paper mulberry helps prevent soil erosion, forming a stable soil and water conservation system together with eucalyptus. The leaves and branches of paper mulberry can also provide shade, reducing soil moisture evaporation, maintaining soil moisture, and improving soil climate.

[0026] 5. This invention combines eucalyptus and paper mulberry planting to increase soil fertility. Paper mulberry has a well-developed root system and strong nitrogen-fixing ability of rhizobia, which can improve soil fertility, slow down the predatory consumption of soil by eucalyptus, maintain the sustainability of soil fertility, reduce fertilizer use, thereby reducing soil pollution caused by excessive fertilization, preventing soil acidification and compaction, and maintaining soil ecological balance.

[0027] 6. This invention uses eucalyptus-specific fertilizer as the main component for topdressing eucalyptus trees, combined with compound microbial fertilizer and seaweed fertilizer. The eucalyptus-specific fertilizer provides eucalyptus trees with macronutrients such as nitrogen, phosphorus, and potassium; the compound microbial fertilizer enhances the activity of beneficial microorganisms in the soil, improves the soil microecological environment, and promotes the absorption and transformation of nutrients by eucalyptus roots; the seaweed fertilizer is rich in active substances such as alginic acid and mannitol, which can enhance the stress resistance of eucalyptus trees and improve their adaptability to adverse environments. This fertilizer combination meets the growth needs of eucalyptus trees, increases their growth rate, and achieves efficient and sustainable development of eucalyptus planting.

[0028] 7. This invention uses urea as the main fertilizer for paper mulberry, combined with slow-release fertilizer, microbial inoculant fertilizer, and seaweed fertilizer. Urea serves as the nitrogen source for paper mulberry growth, promoting lush foliage, increasing photosynthetic efficiency, and accelerating growth. Slow-release fertilizer has a long-lasting effect, preventing nutrient loss from single application, meeting the growth needs of paper mulberry, extending nutrient supply time, and improving nutrient utilization. Microbial inoculant fertilizer contains various beneficial microorganisms, such as nitrogen-fixing bacteria and phosphorus-fixing bacteria, which can fix atmospheric nitrogen and decompose phosphorus, potassium, and other minerals in the soil, converting them into forms that plants can absorb, improving the soil microecological environment, enhancing the paper mulberry's resistance to stress, and promoting root growth. Seaweed fertilizer contains active substances such as alginic acid, mannitol, and betaine, which can improve the paper mulberry's resistance to stress, stimulate root development, increase photosynthetic efficiency, promote nutrient absorption, and improve the quality and yield of paper mulberry. Fertilization using this combination of fertilizers can meet the growth needs of paper mulberry, increase its growth rate, and thus increase its yield. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the interplanting of eucalyptus and paper mulberry in Example 1.

[0030] Figure 2 This is a schematic diagram of the interplanting of eucalyptus and paper mulberry in Example 2.

[0031] Figure 3 This is a schematic diagram of the interplanting of eucalyptus and paper mulberry in Example 3.

[0032] Figure 4 This is a schematic diagram of the interplanting of eucalyptus and paper mulberry in Example 4.

[0033] Figure 5 This is a schematic diagram of the interplanting of eucalyptus and paper mulberry in Example 5.

[0034] Figure 6 This is a schematic diagram of the interplanting of eucalyptus and paper mulberry in Example 6.

[0035] Figure 1-6 In the markings: ▲ represents eucalyptus trees, Represents paper mulberry.

[0036] Figure 7 This is a diagram of the hybrid paper mulberry seedlings from Example 1.

[0037] Figure 8 This is a diagram of the preparation for full-scale reclamation and the application of organic microbial fertilizer in Example 1.

[0038] Figure 9 This is a graph showing the yield of eucalyptus and paper mulberry trees measured in Example 1.

[0039] Figure 10 This is a growth effect diagram of the first year of the intercropping of eucalyptus and paper mulberry in Example 1.

[0040] Figure 11 This is a growth effect diagram of the second year of the intercropping of eucalyptus and paper mulberry in Example 1.

[0041] Figure 12 This is a growth effect diagram of the third year of the intercropping of eucalyptus and paper mulberry in Example 1.

[0042] Figure 13 This is a diagram of paper mulberry planting in Comparative Example 2.

[0043] Figure 14 This is a diagram showing the growth effect of a pure mulberry forest in the first year in Comparative Example 2.

[0044] Figure 15 This is a diagram showing the growth effect of the pure mulberry forest in the second year in Comparative Example 2.

[0045] Figure 16 This is a diagram showing the growth effect of the pure mulberry forest in the third year in Comparative Example 2. Detailed Implementation

[0046] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of protection of the present invention.

[0047] Example 1 A method for intercropping eucalyptus and paper mulberry trees includes the following steps: (1) Forest land preparation: The experimental site is located in the Liangfengjiang Luyoushan Experimental Base in Nanning, Guangxi, with a slope of ≤25 degrees. 。 The planting area is 20 mu (approximately 3.3 hectares) of forest land with an altitude below 500m, deep soil (≥60cm), fertile soil, and good drainage. Full reclamation and preparation for cultivation (e.g.) are adopted. Figure 8 Evenly spread 300 kg / mu of organic microbial fertilizer and deep plow the soil to a depth of 30 cm. Then dig planting holes. The planting holes for eucalyptus trees are 30 cm × 30 cm × 50 cm, and the planting holes for paper mulberry trees are 25 cm × 25 cm × 20 cm. When digging the holes, place the topsoil on top of the holes and remove debris, stones, etc., and clean the holes so that the topsoil can be returned to the holes.

[0048] (2) Afforestation and intercropping: Planting should be done in March, with eucalyptus and paper mulberry planted simultaneously. Before planting, apply 1 kg of farmyard manure as base fertilizer to each eucalyptus planting hole and 1 kg of farmyard manure as base fertilizer to each paper mulberry planting hole, mixing them evenly with the soil in the hole. Select tissue culture seedlings of Eucalyptus urophylla and hybrid paper mulberry (e.g., Figure 7 When planting, remove the nutrient bags and plant the eucalyptus trees in the planting holes; plant the eucalyptus trees with a spacing of 2m × 5m, plant them deeply and compact the soil, ensuring the root collar is 3cm below the ground surface, and water thoroughly to settle the roots; plant three rows of paper mulberry trees parallel to the eucalyptus trees in the 5m spacing (planting pattern diagram as shown in the figure). Figure 1As shown in the figure, plant the plants with a row spacing of 1.2m × 0.55m, cover with soil, and water until the moisture content is 80%.

[0049] (3) Nurturing and Management: Eucalyptus cultivation and management: Within 2 months after eucalyptus planting, promptly replant any missing seedlings or dead trees; 3 months after planting, combine cultivation with weeding, soil mounding, and straightening of the seedlings; within 3 years after planting, weed and loosen the soil twice a year, and apply fertilizer composed of eucalyptus-specific fertilizer, compound microbial fertilizer, and seaweed fertilizer in a weight ratio of 5:3:1, with an application rate of 0.6 kg per tree. Dig a fertilization trench (30 cm long, 20 cm wide, and 20 cm deep) 30 cm away from the trunk, evenly spread the fertilizer in the trench, and then cover it tightly with soil, with a soil thickness of not less than 15 cm; after the eucalyptus trees grow to 3 m tall, prune the branches below 2 m, retaining the main trunk and removing the basal side branches.

[0050] Paper mulberry cultivation and management: Within one week after planting, maintain the soil moisture content at 80% until the seedlings emerge and survive. If there are few or missing seedlings, replant them in time. Weed the paper mulberry planting area at the same time as weeding the eucalyptus planting area. Apply fertilizer twice during the paper mulberry growing season. The fertilizer should be a mixture of urea, slow-release fertilizer, microbial inoculant fertilizer and seaweed fertilizer in a weight ratio of 7:2:0.5:1. Apply 0.15 kg of fertilizer per tree and spread the fertilizer evenly in the circular trench and cover it with soil.

[0051] (4) Harvesting and utilization of paper mulberry: The paper mulberry is harvested for the first time when it grows to 100cm. After that, it is harvested again when it grows to 150cm. It is harvested 4 times a year. The stubble height is 30cm each time. After the paper mulberry grows new buds again, the fertilization steps of paper mulberry in step (3) are repeated. The harvested paper mulberry is used as fodder or made into hay for later use.

[0052] Example 2 A method for intercropping eucalyptus and paper mulberry trees includes the following steps: (1) Forest land preparation: The experimental site is located in the Liangfengjiang Luyoushan Experimental Base in Nanning, Guangxi, with a slope of ≤25 degrees. 。 The planting area is 20 mu (approximately 3.3 hectares) of forest land with an altitude below 500m, deep soil (≥60cm), fertile soil, and good drainage. Full cultivation and preparation are adopted, with 250kg / mu of organic microbial fertilizer evenly spread and deep plowing to a depth of 25cm. Then, planting holes are dug. The planting holes for eucalyptus are 28cm×28cm×45cm, and the planting holes for paper mulberry are 23cm×23cm×18cm. When digging the holes, topsoil is placed on top of the holes, and debris, stones, etc., are removed and cleaned to allow topsoil to return to the holes.

[0053] (2) Afforestation and intercropping: The planting period is selected in March, with eucalyptus and paper mulberry planted at the same time. Before planting, apply 100g of compound fertilizer as base fertilizer to each eucalyptus planting hole and 0.8kg of farmyard manure as base fertilizer to each paper mulberry planting hole, and mix them evenly with the soil in the hole. Select tissue culture seedlings of Eucalyptus urophylla and hybrid paper mulberry tissue culture seedlings. Remove the nutrient bags when planting and plant them in the planting holes; the planting spacing of eucalyptus is 2m×5m, plant deeply and compact the soil, with the root collar 2cm below the ground surface, and water thoroughly; plant 3 rows of paper mulberry parallel to the eucalyptus in the 5m spacing (planting pattern diagram as shown in the figure). Figure 2 As shown in the figure, plant the plants with a row spacing of 1.2m × 0.7m, cover with soil, and water until the moisture content is 70%.

[0054] (3) Nurturing and Management: Eucalyptus cultivation and management: Within one month of afforestation, promptly replant any missing or dead seedlings; three months after planting, combine cultivation with weeding, soil mounding, and straightening of the seedlings; within three years of planting, weed and loosen the soil twice a year, and apply fertilizer composed of eucalyptus-specific fertilizer, compound microbial fertilizer, and seaweed fertilizer in a weight ratio of 6:2:1, at a rate of 0.5 kg per tree. Dig a fertilization trench (30 cm long, 20 cm wide, and 20 cm deep) 50 cm away from the trunk, evenly spread the fertilizer in the trench, and then cover it tightly with soil, with a soil thickness of not less than 15 cm; after the eucalyptus trees grow to 3 m tall, prune the branches below 2 m, retaining the main trunk and removing the basal side branches.

[0055] Paper mulberry cultivation and management: Within one week after planting, maintain the soil moisture content at 70% until the seedlings emerge and survive. If there are few or missing seedlings, replant them in time. Weed the paper mulberry planting area at the same time as weeding the eucalyptus planting area. Apply fertilizer twice during the paper mulberry growing season. The fertilizer should be a mixture of urea, slow-release fertilizer, microbial inoculant fertilizer and seaweed fertilizer in a weight ratio of 6:1:0.5:1. Apply 0.20 kg of fertilizer per tree and spread the fertilizer evenly in the circular trench and cover it with soil.

[0056] (4) Harvesting and utilization of paper mulberry: The paper mulberry is harvested for the first time when it grows to 100cm. After that, it is harvested again when it grows to 120cm. It is harvested 3 times a year. The stubble height is 30cm each time. After the paper mulberry grows new buds again, the fertilization steps of paper mulberry in step (3) are repeated. The harvested paper mulberry is used as fodder or made into hay for later use.

[0057] Example 3 A method for intercropping eucalyptus and paper mulberry trees includes the following steps: (1) Forest land preparation: The experimental site is located in the Liangfengjiang Luyoushan Experimental Base in Nanning, Guangxi, with a slope of ≤25 degrees. 。The planting area is 20 mu (approximately 3.3 hectares) of forest land with an altitude below 500m, deep soil (≥60cm), fertile soil, and good drainage. Full cultivation and preparation are adopted, with 280kg / mu of organic microbial fertilizer evenly spread and deep plowing to a depth of 30cm. Then, planting holes are dug. The planting holes for eucalyptus are 30cm×30cm×45cm, and the planting holes for paper mulberry are 25cm×25cm×18cm. When digging the holes, topsoil is placed on top of the holes, and debris, stones, etc., are removed and cleaned to allow topsoil to return to the holes.

[0058] (2) Afforestation and intercropping: The planting period is selected in March, with eucalyptus and paper mulberry planted at the same time. Before planting, apply 0.8 kg of farmyard manure as base fertilizer to each eucalyptus planting hole and 50 g of compound fertilizer as base fertilizer to each paper mulberry planting hole, and mix them evenly with the soil in the hole. Select tissue culture seedlings of Eucalyptus urophylla and hybrid paper mulberry tissue culture seedlings. Remove the nutrient bags when planting and plant them in the planting holes; the planting spacing of eucalyptus is 3m×6m, plant deeply and compact the soil, with the root collar 3cm below the ground surface, and water thoroughly; plant 4 rows of paper mulberry parallel to the eucalyptus in the 6m spacing (planting pattern diagram as shown in the figure). Figure 3 As shown in the figure, plant the plants with a row spacing of 1.2m × 0.55m, cover with soil, and water until the moisture content is 75%.

[0059] (3) Nurturing and Management: Eucalyptus cultivation and management: Within 2 months after eucalyptus planting, promptly replant any missing seedlings or dead trees; 3 months after planting, combine cultivation with weeding, soil mounding, and straightening of the seedlings; within 3 years after planting, weed and loosen the soil twice a year, and apply fertilizer composed of eucalyptus-specific fertilizer, compound microbial fertilizer, and seaweed fertilizer in a weight ratio of 6:2.5:1, with an application rate of 0.5 kg per tree. Dig a fertilizer trench (28 cm long, 20 cm wide, and 18 cm deep) 40 cm away from the trunk, evenly spread the fertilizer in the trench, and then cover it tightly with soil, with a soil thickness of not less than 15 cm; after the eucalyptus trees grow to 3 m in height, prune the branches below 2 m, retain the main trunk, and remove the basal side branches.

[0060] Paper mulberry cultivation and management: Within one week after planting, maintain the soil moisture content at 75% until the seedlings emerge and survive. If there are few or missing seedlings, replant them in time. Weed the paper mulberry planting area at the same time as weeding the eucalyptus planting area. Apply fertilizer twice during the paper mulberry growing season. The fertilizer should be a mixture of urea, slow-release fertilizer, microbial inoculant fertilizer and seaweed fertilizer in a weight ratio of 7:1:0.3:1. Apply 0.18 kg of fertilizer per tree and spread the fertilizer evenly in the circular trench and cover it with soil.

[0061] (4) Harvesting and utilization of paper mulberry: The paper mulberry is harvested for the first time when it grows to 100cm. After that, it is harvested again when it grows to 150cm. It is harvested 4 times a year. The stubble height is 30cm each time. After the paper mulberry grows new buds again, the fertilization steps of paper mulberry in step (3) are repeated. The harvested paper mulberry is used as fodder or made into hay for later use.

[0062] Example 4 A method for intercropping eucalyptus and paper mulberry trees includes the following steps: (1) Forest land preparation: The experimental site is located in the Liangfengjiang Luyoushan Experimental Base in Nanning, Guangxi, with a slope of ≤25 degrees. 。 The planting area is 20 mu (approximately 3.3 hectares) of forest land with an altitude below 500m, deep soil (≥60cm), fertile soil, and good drainage. Full cultivation and preparation are adopted, with 250kg / mu of organic microbial fertilizer evenly spread and deep plowing to a depth of 30cm. Then, planting holes are dug. The planting holes for eucalyptus are 28cm×28cm×50cm, and the planting holes for paper mulberry are 23cm×23cm×20cm. When digging the holes, topsoil is placed on top of the holes, and debris, stones, etc., are removed and cleaned to allow for topsoil back into the holes.

[0063] (2) Afforestation and intercropping: The planting period is selected in March, with eucalyptus and paper mulberry planted at the same time. Before planting, apply 80g of compound fertilizer as base fertilizer to each eucalyptus planting hole and 40g of compound fertilizer as base fertilizer to each paper mulberry planting hole, and mix them evenly with the soil in the hole. Select tissue culture seedlings of Eucalyptus urophylla and hybrid paper mulberry tissue culture seedlings. Remove the nutrient bags when planting and plant them in the planting holes; the planting spacing of eucalyptus is 3m×6m, plant deeply and compact the soil, with the root collar 2cm below the ground surface, and water thoroughly to settle the roots; plant 4 rows of paper mulberry parallel to the eucalyptus in the 6m spacing (planting pattern diagram as shown in the figure). Figure 4 As shown in the figure, plant the plants with a row spacing of 1.2m × 0.7m, cover with soil, and water until the moisture content is 80%.

[0064] (3) Nurturing and Management: Eucalyptus cultivation and management: Within one month of afforestation, promptly replant any missing or dead seedlings; three months after planting, combine cultivation with weeding, soil mounding, and straightening of the seedlings; within three years of planting, weed and loosen the soil twice a year, and apply fertilizer composed of eucalyptus-specific fertilizer, compound microbial fertilizer, and seaweed fertilizer in a weight ratio of 5:3:1, with an application rate of 0.55 kg per tree. Dig a fertilization trench (25 cm long, 18 cm wide, and 20 cm deep) 45 cm away from the trunk, evenly spread the fertilizer in the trench, and then cover it tightly with soil, with a soil thickness of not less than 15 cm; after the eucalyptus trees grow to 3 m tall, prune the branches below 2 m, retaining the main trunk and removing the basal side branches.

[0065] Paper mulberry cultivation and management: Within one week after planting, maintain the soil moisture content at 80% until the seedlings emerge and survive. If there are few or missing seedlings, replant them in time. Weed the paper mulberry planting area at the same time as weeding the eucalyptus planting area. Apply fertilizer three times during the paper mulberry growing season. The fertilizer should be a mixture of urea, slow-release fertilizer, microbial inoculant fertilizer and seaweed fertilizer in a weight ratio of 6.5:2:0.4:1. Apply 0.15 kg of fertilizer per tree and spread the fertilizer evenly in the circular trench and cover it with soil.

[0066] (4) Harvesting and utilization of paper mulberry: The paper mulberry is harvested for the first time when it grows to 100cm. After that, it is harvested again when it grows to 130cm. It is harvested twice a year. The stubble height is 25cm each time. After the paper mulberry grows new buds again, the fertilization steps of paper mulberry in step (3) are repeated. The harvested paper mulberry is used as fodder or made into hay for later use.

[0067] Example 5 A method for intercropping eucalyptus and paper mulberry trees includes the following steps: (1) Forest land preparation: The experimental site is located in the Liangfengjiang Luyoushan Experimental Base in Nanning, Guangxi, with a slope of ≤25 degrees. 。 The planting area is selected from forest land below 500m altitude with deep soil (≥60cm), fertile soil, and good drainage, covering an area of ​​20 mu (approximately 1.3 hectares). Full cultivation and preparation are adopted, with 300kg / mu (approximately 200kg / hectare) of organic microbial fertilizer evenly spread and deep plowing to a depth of 30cm. Then, planting holes are dug. The planting holes for eucalyptus are 30cm×30cm×50cm, and the planting holes for paper mulberry are 25cm×25cm×20cm. When digging the holes, topsoil is placed on top of the holes, and debris, stones, etc., are removed and cleaned to allow for topsoil back into the holes.

[0068] (2) Afforestation and intercropping: The planting period is selected in March, with eucalyptus and paper mulberry planted at the same time. Before planting, apply 0.8 kg of farmyard manure as base fertilizer to each eucalyptus planting hole and 50 g of compound fertilizer as base fertilizer to each paper mulberry planting hole, and mix them evenly with the soil in the hole. Select tissue culture seedlings of Eucalyptus urophylla and hybrid paper mulberry tissue culture seedlings. Remove the nutrient bags when planting and plant them in the planting holes; the planting spacing of eucalyptus is 4m×6m, plant deeply and compact the soil, with the root collar 2cm below the ground surface, and water thoroughly to settle the roots; plant 4 rows of paper mulberry parallel to the eucalyptus in the 6m spacing (planting pattern diagram as shown in the figure). Figure 5 As shown in the figure, plant the plants with a row spacing of 1.2m × 0.55m, cover with soil, and water until the moisture content is 70%.

[0069] (3) Nurturing and Management: Eucalyptus cultivation and management: Within 2 months after eucalyptus planting, promptly replant any missing seedlings or dead trees; 3 months after planting, combine cultivation with weeding, soil mounding, and straightening of the seedlings; within 3 years after planting, weed and loosen the soil twice a year, and apply fertilizer composed of eucalyptus-specific fertilizer, compound microbial fertilizer, and seaweed fertilizer in a weight ratio of 5.5:3:1, with an application rate of 0.5 kg per tree. Dig a fertilization trench (25 cm long, 20 cm wide, and 18 cm deep) 35 cm away from the trunk, evenly spread the fertilizer in the trench, and then cover it tightly with soil, with a soil thickness of not less than 15 cm; after the eucalyptus trees grow to 3 m tall, prune the branches below 2 m, retaining the main trunk and removing the basal side branches.

[0070] Paper mulberry cultivation and management: Within one week after planting, maintain the soil moisture content at 70% until the seedlings emerge and survive. If there are few or missing seedlings, replant them in time. Weed the paper mulberry planting area at the same time as weeding the eucalyptus planting area. Apply fertilizer twice during the paper mulberry growing season. The fertilizer should be a mixture of urea, slow-release fertilizer, microbial inoculant fertilizer and seaweed fertilizer in a weight ratio of 6:1.5:0.5:1. Apply 0.20 kg of fertilizer per tree and spread the fertilizer evenly in the circular trench and cover it with soil.

[0071] (4) Harvesting and utilization of paper mulberry: The paper mulberry is harvested for the first time after it grows to 100cm. After that, it is harvested again after it grows to 100cm. It is harvested 4 times a year. The stubble height is 30cm each time. After the paper mulberry grows new buds again, the fertilization steps of paper mulberry in step (3) are repeated. The harvested paper mulberry is used as fodder or made into hay for later use.

[0072] Example 6 A method for intercropping eucalyptus and paper mulberry trees includes the following steps: (1) Forest land preparation: The experimental site is located in the Liangfengjiang Luyoushan Experimental Base in Nanning, Guangxi, with a slope of ≤25 degrees. 。 The planting area is 20 mu (approximately 3.3 hectares) of forest land with an altitude below 500m, deep soil (≥60cm), fertile soil, and good drainage. Full cultivation and preparation are adopted, with 275kg / mu of organic microbial fertilizer evenly spread and deep plowing to a depth of 25cm. Then, planting holes are dug. The planting holes for eucalyptus are 30cm×30cm×50cm, and the planting holes for paper mulberry are 25cm×25cm×20cm. When digging the holes, topsoil is placed on top of the holes, and debris and stones are removed and cleaned to allow for topsoil back into the holes.

[0073] (2) Afforestation and intercropping: The planting period is selected in March, with eucalyptus and paper mulberry planted at the same time. Before planting, apply 100g of compound fertilizer as base fertilizer to each eucalyptus planting hole and 0.8kg of farmyard manure as base fertilizer to each paper mulberry planting hole, and mix them evenly with the soil in the hole. Select tissue culture seedlings of Eucalyptus urophylla and hybrid paper mulberry tissue culture seedlings. Remove the nutrient bags when planting and plant them in the planting holes; the planting spacing of eucalyptus is 4m×6m, plant deeply and compact the soil, with the root collar 3cm below the ground surface, and water thoroughly; plant 4 rows of paper mulberry parallel to the eucalyptus in the 6m spacing (planting pattern diagram as shown in the figure). Figure 6 As shown in the figure, plant the plants with a row spacing of 1.2m × 0.7m, cover with soil, and water until the moisture content is 80%.

[0074] (3) Nurturing and Management: Eucalyptus cultivation and management: Within 2 months after eucalyptus planting, promptly replant any missing seedlings or dead trees; 3 months after planting, combine cultivation with weeding, soil mounding, and straightening of the seedlings; within 3 years after planting, weed and loosen the soil twice a year, and apply fertilizer composed of eucalyptus-specific fertilizer, compound microbial fertilizer, and seaweed fertilizer in a weight ratio of 5:3:1, with an application rate of 0.55 kg per tree. Dig a fertilization trench (30 cm long, 20 cm wide, and 20 cm deep) 50 cm away from the trunk, evenly spread the fertilizer in the trench, and then cover it tightly with soil, with a soil thickness of not less than 15 cm; after the eucalyptus trees grow to 3 m tall, prune the branches below 2 m, retaining the main trunk and removing the basal side branches.

[0075] Paper mulberry cultivation and management: Within one week after planting, maintain the soil moisture content at 80% until the seedlings emerge and survive. If there are few or missing seedlings, replant them in time. Weed the paper mulberry planting area at the same time as weeding the eucalyptus planting area. Apply fertilizer three times during the paper mulberry growing season. The fertilizer should be a mixture of urea, slow-release fertilizer, microbial inoculant fertilizer and seaweed fertilizer in a weight ratio of 6:2:0.3:1. Apply 0.15 kg of fertilizer per tree and spread the fertilizer evenly in the circular trench and cover it with soil.

[0076] (4) Harvesting and utilization of paper mulberry: The paper mulberry is harvested for the first time when it grows to 100cm. After that, it is harvested again when it grows to 120cm. It is harvested 4 times a year. The stubble height is 30cm each time. After the paper mulberry grows new buds again, the fertilization steps of paper mulberry in step (3) are repeated. The harvested paper mulberry is used as fodder or made into hay for later use.

[0077] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the planting area in Comparative Example 1 is 5 mu, and the eucalyptus forest with a spacing of 2m×5m is planted without intercropping paper mulberry. The other planting methods are the same as those in Example 1.

[0078] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, the planting area is 5 mu (approximately 0.33 hectares), and the trees are planted in a pure stands of mulberry trees with a spacing of 1.2m × 0.55m (e.g., ...). Figure 13 No eucalyptus trees were interplanted, and the remaining planting methods were the same as in Example 1.

[0079] Comparative Example 3 In Comparative Example 3, the eucalyptus trees were planted with a spacing of 1.5m × 4m. Four rows of paper mulberry trees were planted parallel to the eucalyptus trees in the 4m spacing between the eucalyptus trees, with a spacing of 0.8m × 0.4m between the trees. The remaining planting methods were the same as in Example 1.

[0080] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the planting area in Comparative Example 4 is 5 mu, and only eucalyptus-specific fertilizer is used when applying fertilizer to eucalyptus trees in step (3). The other planting methods are the same as those in Example 1.

[0081] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the planting area in Comparative Example 5 is 5 mu, and only urea is used when applying fertilizer to the paper mulberry in step (3). The other planting methods are the same as those in Example 1.

[0082] The tree height, diameter at breast height (DBH), and single-tree volume of eucalyptus trees in Examples 1-6 and Comparative Examples 1-5 after 3 years of planting were statistically analyzed, and the results are shown in Table 1 below.

[0083] Table 1. Comparison of eucalyptus growth under different planting methods in Examples 1-6 and Comparative Examples 1-5

[0084] As shown in Table 1, the eucalyptus trees in Example 4 had the highest average tree height and diameter at breast height (DBH). In Example 4, eucalyptus and paper mulberry were interplanted and planted at a reasonable density. The eucalyptus spacing was 3m × 6m, with a relatively large area of ​​open space between rows. The paper mulberry density was 1.2m × 0.7m, providing ample space for eucalyptus growth both above and below ground. Furthermore, the nitrogen fixation by the paper mulberry increased soil fertility, providing sufficient nutrients for eucalyptus growth. Precise fertilization of the eucalyptus also met its growth needs, resulting in rapid and vigorous growth. This explains why the eucalyptus trees in Example 4 grew best.

[0085] Compared to Comparative Example 1, the volume of individual eucalyptus trees in Example 1 increased by 75%, indicating that intercropping paper mulberry under eucalyptus trees increases soil fertility through nitrogen fixation, thus promoting eucalyptus growth. Compared to Comparative Examples 3, 4, and 5, the volume of individual eucalyptus trees in Example 1 increased by 86.67%, 33.33%, and 24.44%, respectively. The low volume of individual eucalyptus trees in Comparative Examples 3, 4, and 5 is due to the following reasons: In Comparative Example 3, the planting density of eucalyptus and paper mulberry was too high, resulting in insufficient sunlight and weak photosynthesis for eucalyptus, strong competition for water and nutrients, restricted growth, and increased susceptibility to pests and diseases, leading to a decrease in eucalyptus quality; in Comparative Example 4, the applied fertilizer could not meet the growth needs of eucalyptus, resulting in slow growth; in Comparative Example 5, the paper mulberry was fertilized only with urea, which had a single nutrient composition and could not meet the growth needs, resulting in slow growth. The limited ability of paper mulberry to improve soil structure also affected the growth of eucalyptus. This invention demonstrates that by intercropping eucalyptus and paper mulberry trees, planting them at appropriate density, and applying precise fertilization, the healthy and rapid growth of eucalyptus and paper mulberry trees can be promoted, thereby directly improving economic benefits.

[0086] Table 2. Paper mulberry yield under different planting methods in Examples 1-6 and Comparative Examples 1-5

[0087] As can be seen from the data in Table 2, the first year of growth of paper mulberry trees in Examples 1-6 and Comparative Examples 2-5 was relatively short, resulting in lower yields. The highest yield in Example 4 was only 2036.82 kg / 667 m². 2 In the second year, the yield of paper mulberry under various intercropping patterns increased significantly, reaching a maximum of 6110.46 kg / 667 m³ in Example 4. 2 This represents a twofold increase compared to the first year, with an average annual yield of 4569.27 kg / 667m³. 2 .

[0088] Figure 10-12 The images show the growth effects of the eucalyptus and paper mulberry intercropping in the first, second, and third years of Example 1. Figure 14-16 The figures show the growth effects of the pure mulberry forest in Comparative Example 2 in the first, second, and third years. Compared with Comparative Example 2, the average annual yield of mulberry in Example 1 increased by 51.10%. The reason for the high yield in Example 1 is that the intercropping of eucalyptus and mulberry, with the eucalyptus canopy above and the shrubs below, can fully utilize light, heat, and land resources. In other words, the eucalyptus provides shade, reducing water evaporation from the mulberry, while the mulberry fixes nitrogen, improving soil fertility and forming a nutrient cycle. Therefore, the environmental conditions under the intercropping are sufficient in water and fertilizer, resulting in good mulberry growth. In contrast, Comparative Example 2 is a pure mulberry forest, which does not have favorable natural conditions, so the mulberry growth is poor.

[0089] Compared with Comparative Examples 3, 4, and 5, the average annual yield of paper mulberry in Example 1 increased by 14.93%, 40.74%, and 50.83%, respectively. The reason for the low average annual yield of paper mulberry in Comparative Examples 3, 4, and 5 is that in Comparative Example 3, the planting density of eucalyptus and paper mulberry was too high, which intensified competition among paper mulberry trees and resulted in insufficient light, water, and nutrients, leading to slow growth, stunted plants, and susceptibility to pests and diseases, thus reducing yield. In Comparative Example 4, the poor growth of eucalyptus affected the growth of paper mulberry, resulting in low paper mulberry yield. In Comparative Example 5, the applied fertilizer could not meet the growth needs of paper mulberry, resulting in slow growth and low paper mulberry yield.

[0090] In summary, factors such as monoculture (pure forests), planting density, and fertilization all affect the growth of eucalyptus and paper mulberry, thereby impacting their yields. This invention, through intercropping of eucalyptus and paper mulberry, reasonable dense planting, and precise fertilization, not only alleviates soil degradation and biodiversity loss caused by monocultures of eucalyptus, but also effectively integrates the long-term benefits of eucalyptus with the short-term benefits of paper mulberry, aiming to improve economic, ecological, and social benefits.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for intercropping eucalyptus and paper mulberry trees, characterized in that, Includes the following steps: (1) Forest land preparation: Select slopes ≤25 。 The planting area is a forest land with a depth of 500m or less, deep soil, fertile soil and good drainage. The whole land is cultivated and prepared. Organic fertilizer is spread evenly and the soil is deeply cultivated and turned over to a depth of 25-30cm. Then, planting holes for eucalyptus and paper mulberry are dug. When digging the holes, the topsoil is placed on top of the holes and debris, stones and other objects are picked out and cleaned so that the topsoil can be put back into the holes. (2) Afforestation and intercropping: The planting period is from February to May. Eucalyptus and paper mulberry are planted at the same time. Before planting, apply base fertilizer to the planting hole and mix it evenly with the soil in the hole. When planting, remove the nutrient bag and plant it in the planting hole. The planting spacing of eucalyptus is (2-4)m × ​​(5-6)m. Plant it deeply and compact it. The root collar is 2-3cm below the ground surface. Water it thoroughly to settle the roots. Plant paper mulberry in parallel with eucalyptus between the rows of eucalyptus. The planting spacing is 1.2m × (0.55-0.7)m. Cover it with soil and water it until the moisture content is 70-80%. (3) Nurturing and Management: Eucalyptus cultivation and management: Within 1 to 2 months after eucalyptus planting, promptly replant any missing seedlings or dead trees; 3 months after planting, combine tending with weeding, soil mounding, and straightening of seedlings; within 3 years after planting, weed and loosen the soil twice a year, combined with topdressing; after eucalyptus trees grow to 2.8 to 3m in height, prune the branches below 2m, retaining the main trunk and removing the basal side branches; Paper mulberry cultivation and management: Within one week after planting, maintain the soil moisture content at 70-80% until the seedlings emerge and survive. If there are few or missing seedlings, replant them in time. Weed the paper mulberry planting area at the same time as weeding the eucalyptus planting area. Apply fertilizer 2-3 times during the paper mulberry growing season, mainly nitrogen fertilizer. (4) Harvesting and utilization of paper mulberry: The paper mulberry is harvested for the first time when it grows to 100cm. After that, it is harvested again when it grows to 100-150cm. It is harvested 2-4 times a year. The stubble height is 25-30cm each time. After the paper mulberry grows new buds again, the fertilization steps of paper mulberry in step (3) are repeated. The harvested paper mulberry is used as fodder or made into hay for later use.

2. The method for interplanting eucalyptus and paper mulberry according to claim 1, characterized in that, In step (2), when the eucalyptus planting spacing is 2m×5m, three rows of paper mulberry trees are planted parallel to the eucalyptus trees in the 5m spacing between the eucalyptus trees.

3. The method for interplanting eucalyptus and paper mulberry according to claim 1, characterized in that, In step (2), when the eucalyptus planting spacing is (3-4)m×6m, four rows of paper mulberry trees are planted parallel to the eucalyptus trees in the 6m spacing between the eucalyptus trees.

4. The method for interplanting eucalyptus and paper mulberry according to any one of claims 1-3, characterized in that, In step (2), the spacing between the rows of paper mulberry trees is 1.2m × 0.55m or 1.2m × 0.7m.

5. The method for interplanting eucalyptus and paper mulberry according to claim 1, characterized in that, In step (2), 0.8-1 kg of farmyard manure or 80-100 g of compound fertilizer is applied to each eucalyptus planting hole as base fertilizer; 0.8-1 kg of farmyard manure or 40-50 g of compound fertilizer is applied to each paper mulberry planting hole as base fertilizer.

6. The method for interplanting eucalyptus and paper mulberry according to claim 1, characterized in that, In step (3), the fertilizer for eucalyptus topdressing is composed of eucalyptus-specific fertilizer, compound microbial fertilizer and seaweed fertilizer mixed in a weight ratio of 5-6:2-3:

1. The amount of fertilizer applied to each tree is 0.5-0.6 kg. A fertilizer trench is dug 30-50 cm away from the trunk. The fertilizer is evenly spread into the fertilizer trench and then covered with soil. The soil covering thickness is not less than 15 cm.

7. The method for interplanting eucalyptus and paper mulberry according to claim 6, characterized in that, The fertilizer trench is 25-30cm long, 18-20cm wide, and 18-20cm deep.

8. The method for interplanting eucalyptus and paper mulberry according to claim 1, characterized in that, In step (3), the fertilizer for the top dressing of the paper mulberry tree is composed of urea, slow-release fertilizer, microbial inoculant fertilizer and seaweed fertilizer in a weight ratio of 6-7:1-2:0.3-0.5:

1. The amount of fertilizer applied to each tree is 0.15-0.2 kg. The fertilizer is evenly spread in the circular trench and covered with soil.

9. The method for interplanting eucalyptus and paper mulberry according to claim 1, characterized in that, In step (1), the specifications of the eucalyptus planting pit are (28~30)cm×(28~30)cm×(45~50)cm; the specifications of the paper mulberry planting pit are (23~25)cm×(23~25)cm×(18~20)cm.

10. The method for interplanting eucalyptus and paper mulberry according to claim 1, characterized in that, In step (1), the amount of organic microbial fertilizer used is 250-300 kg / mu.

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