A method of interplanting a citrus orchard with a plurality of pasture grasses

Abstract

This invention discloses a method for intercropping multiple forage grasses in citrus orchards. Addressing the drawbacks of traditional clean cultivation management and single-grass intercropping in citrus orchards, it employs a mixed sowing of four varieties: ryegrass, white clover, gnaphalium affine, and milkvetch. It includes standardized steps for orchard pretreatment, seed pretreatment, precision sowing, seedling management, growth period management, forage harvesting and returning to the field, and water and fertilizer regulation. Strict control of parameters at each stage is maintained, and a specific ratio of compound bio-fertilizer is selected to optimize the citrus water and fertilizer management scheme. This invention achieves year-round closed coverage of the citrus orchard through the complementary characteristics of the four forage grasses, improving the control rate of noxious weeds, reducing soil erosion, increasing soil organic matter content, and increasing citrus yield per acre. It combines the advantages of improving soil fertility, suppressing weeds and conserving moisture, improving quality and efficiency, and promoting a green and ecological environment, thus constructing a highly efficient and sustainable citrus ecological planting system.

Description

Technical Field

[0001] This invention relates to the field of orchard ecological planting and soil improvement technology, and more specifically to an ecological cultivation method for intercropping multiple forage grasses in citrus orchards. Background Technology

[0002] Citrus, as a core economic fruit in my country, is planted throughout many southern provinces, and its industry scale ranks among the world's top. Traditional citrus orchards mostly employ a bare-field management model, which has revealed several technical shortcomings over time: First, long-term bare-field management leads to exposed soil, exacerbated soil erosion, damage to soil aggregate structure, prominent problems of compaction and acidification, a continuous decline in organic matter content, and a significant reduction in soil water and fertilizer retention capacity. Second, rampant weed growth in orchards necessitates extensive manual weeding or frequent application of chemical herbicides, increasing planting costs and easily causing pesticide residues, polluting the orchard ecosystem, and disrupting the soil microbial community. Third, bare-field management prevents nutrient recycling, leading to an imbalance in nutrient supply to citrus trees, resulting in nutrient deficiencies, weak growth, and difficulty in steadily improving fruit yield and quality.

[0003] Current orchard ground cover cultivation techniques mostly employ intercropping of single forage varieties, which has significant limitations: single gramineous forages lack nitrogen fixation capacity, requiring additional large amounts of nitrogen fertilizer, resulting in high planting costs; single legume forages have short growing seasons and weak ground cover capacity, leading to poor weed control and competition with citrus trees for water and nutrients; some forages have poor cold resistance and shade tolerance, making year-round orchard coverage impossible, and they are prone to scorching citrus roots in high summer temperatures and dying from low winter temperatures. Even in a few orchards that have attempted mixed sowing of two forage species, problems such as unreasonable ratios, extensive planting and management, and poor ecological complementarity exist, failing to achieve the expected effects in weed control, fertilization, and yield increase, and are difficult to adapt to the industry's needs for efficient, green, and sustainable cultivation in citrus orchards.

[0004] Based on this, developing a method for intercropping pasture in citrus orchards that is adapted to the growth habits of citrus, scientifically matched with forage, standardized in management procedures, and combines ecological and economic benefits, and solving the drawbacks of traditional clean cultivation and existing grass cover technology, has become a technical problem that urgently needs to be solved in the field of citrus planting. Summary of the Invention

[0005] In view of this, the present invention provides a method for intercropping multiple forage grasses in citrus orchards. By scientifically mixing four varieties—ryegrass, white clover, gnaphalium affine, and milkvetch—and optimizing planting and management parameters at each stage, this method solves the problems of soil degradation, rampant weeds, high costs, and ecological imbalance associated with traditional methods. It also overcomes the shortcomings of existing forage grass technologies, such as poor adaptability and weak weed control and fertilization effects. This method achieves the goals of water and soil conservation, suppression of noxious weeds, reduction of chemical fertilizer application, and improvement of soil fertility and citrus yield and quality in citrus orchards, thus constructing a green and efficient ecological citrus planting system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for intercropping multiple forage grasses in citrus orchards, wherein the forage grasses are a mixture of four varieties: ryegrass, white clover, gnaphalium affine, and milkvetch. The total amount of mixed seeds is 3.8-5.2 kg / mu, and the weight ratio of each grass species is as follows: ryegrass 32%-38%, white clover 21%-24%, gnaphalium affine 16%-19%, and milkvetch 22%-26%. Under this ratio, the four forage grass varieties have complementary growth characteristics. Ryegrass is cold-resistant, drought-resistant, and grows rapidly. White clover and milkvetch fix nitrogen and enrich soil, and are shade-resistant and trampling-resistant. Gnaphalium affine grows prostrate and lodging in summer to suppress weeds. This method can achieve year-round coverage in citrus orchards and synergistically improve the effects of weed control, fertilization, and moisture retention.

[0008] Furthermore, the intercropping method of the present invention specifically includes the following steps:

[0009] Step 1: Orchard Pretreatment

[0010] Select citrus orchards with a soil layer thickness of ≥50cm, a soil pH of 5.0-7.0, and good drainage and lighting. Suitable orchards include saplings aged 1-15 years and mature fruit-bearing trees. The terrain includes flat land and gently sloping hills with a slope of ≤15°. Suitable citrus varieties include any one of Wogan, Satsuma mandarin, navel orange, honey mandarin, and rock sugar orange. Thoroughly clean up dead branches, fallen leaves, diseased plant debris, and weed roots in the orchard. Prune diseased and weak citrus branches and retain the inner side of the citrus canopy drip line. Cultivate a 30-50cm root protection strip to prevent pasture grass from competing with the main root system of citrus trees for fertilizer and water; shallowly cultivate between rows to a depth of 10-15cm, and apply 250-350kg of decomposed farmyard manure, 12-18kg of calcium magnesium phosphate fertilizer, and 5-8kg of bio-fertilizer per acre as base fertilizer, spreading them evenly and then tilling them in; dig drainage ditches 12-18cm deep and 15-25cm wide, and add transverse water-blocking ditches in gentle slope orchards to prevent water accumulation, root rot, and soil erosion during the rainy season;

[0011] The bio-fertilizer contains ≥500 million live bacteria per gram. By weight percentage, it consists of 25%-30% Bacillus subtilis inoculant, 20%-25% Bacillus spp. inoculant, 15%-20% Azotobacter chrysotile inoculant, 10%-15% phosphorus-solubilizing and potassium-solubilizing inoculant, and the remainder being carrier additives. The carrier additives are a mixture of well-rotted humic acid, wood ash, and fine sand in a mass ratio of 3:2:1, which has the functions of nitrogen fixation, phosphorus and potassium solubilization, soil improvement, and inhibition of harmful bacteria.

[0012] Step 2: Pretreatment of forage seeds

[0013] After mixing the forage seeds, sun-dry them for 5-8 hours to break their dormancy and kill pathogens on the seed surface. For milkvetch and white clover seeds, soak them in warm water at 40-45℃ for 2.5-3 hours. After draining, mix them with 0.5%-1% of the seed weight of leguminous forage rhizobium inoculant to improve nitrogen fixation efficiency. For ryegrass and bulrush seeds, no soaking is required. Mix them directly with fine sand and wood ash in a mass ratio of 1:4:1 to ensure uniform sowing.

[0014] Step 3: Precision Sowing

[0015] The sowing period is selected in late September to late October in autumn, with the ambient temperature stable at 14-26℃ and the soil moisture content maintained at 60%-70%, which meets the needs of forage grass emergence and overwintering growth. Row sowing is adopted, with a row spacing of 22-28cm and a sowing depth of 0.6-1.0cm. After sowing, cover with 0.4-0.6cm of fine soil and lightly press it down to ensure close contact between the seeds and the soil. Water thoroughly within 24 hours after sowing to settle the roots. In dry weather, spray water to keep the soil moist until the forage grass emerges uniformly. After emergence, water should be controlled appropriately to suppress excessive growth and lodging.

[0016] Step 4: Seedling Management

[0017] Thinning and replanting should be carried out 7-10 days after the forage grass emerges and when the seedlings are 3-6cm tall. Remove diseased, weak, and clump-forming seedlings, and maintain a plant spacing of 6-9cm. Replant in areas with missing seedlings or gaps in the rows in a timely manner to ensure uniform growth of forage grass throughout the orchard. After thinning, apply 150-200kg of well-rotted and diluted biogas slurry per acre as a seedling fertilizer to promote tillering growth. Manually remove any remaining noxious weeds in the field to avoid competition for nutrients. During the rainy season, promptly clear drainage ditches to prevent waterlogging that could lead to root rot and damping-off disease in the forage grass.

[0018] Step 5: Growth Period Management

[0019] Five to seven days before the onset of winter low temperatures, spray the entire orchard with a foliar fertilizer mixture of 0.2%-0.3% potassium dihydrogen phosphate and 0.1% brassinolide to enhance the cold resistance and frost protection of the forage grass, ensuring its survival in winter. After the spring temperature rises, the forage grass enters its vigorous growth period. Timely cut forage grasses that are taller than 45cm to control excessive growth and avoid shading the citrus tree canopy and affecting ventilation and light penetration. Do not spray chemical herbicides throughout the entire process, relying on the dense mulch of mixed forage grass to suppress weed growth. Routine water and fertilizer management and pest and disease control for citrus trees are carried out as usual. There are no symbiotic pests and diseases between the forage grass and citrus trees, and they do not interfere with each other.

[0020] Step Six: Harvesting and Returning Pasture to the Field

[0021] When ryegrass and white clover reach a height of 30-40cm, the first cut should be made, strictly avoiding the peak flowering period and physiological fruit drop period of citrus, to reduce the impact on citrus fruit set; in March-April of the following year, after milkvetch enters its peak flowering period and privet grass has completely fallen over, the entire orchard should be cut; cut 2-3 times a year, with the last cut completed 10-15 days after citrus harvest, to facilitate winter orchard cleanup and nutrient return to the field;

[0022] The stubble height after cutting should be uniformly 8-11cm to ensure the regeneration capacity of the forage. Small-scale machinery or manual cutting should be used to avoid damaging the citrus tree, bark, and root system. The fresh forage after cutting should be distributed and utilized according to the following weight ratio: 70% should be directly used as mulch between the citrus tree basins and rows, with a mulch thickness of 5-9cm, and 30% should be turned into the soil to a depth of 10-15cm as green manure. After turning, 5-10kg of quicklime should be spread per acre to adjust the soil pH and improve the utilization rate of soil nutrients.

[0023] Step 7: Water and Fertilizer Regulation

[0024] After intercropping with forage grasses, relying on the nitrogen-fixing and supplying capabilities of white clover and milkvetch, the amount of nitrogen fertilizer applied to citrus trees can be reduced by 25%-35%. At the same time, potassium fertilizer and organic fertilizer are applied in a targeted manner. Potassium sulfate compound fertilizer is selected, with an increase of 15-20 kg per mu. Well-rotted cake fertilizer is selected, with an increase of 80-120% per mu. It is applied twice a year, in spring when the trees sprout and in autumn when the trees are growing strong, to avoid excessive application of nitrogen fertilizer. During the rainy season, water is controlled and flood prevention is prevented, and the frequency of artificial watering is reduced to maintain the soil moisture content at ≤65%. During the dry season, drip irrigation is used for precise water replenishment to maintain the soil moisture content at 60%-70%. Every year, the soil between the rows is loosened shallowly when returning forage grass to the field to a depth of 8-12 cm, without damaging the roots of the forage grass and the fibrous roots of the citrus trees. After 2-3 years of continuous intercropping, bio-fertilizer is applied to the whole orchard to maintain the soil, with an application rate of 6-10 kg per mu. The composition of the bio-fertilizer is the same as that of the bio-fertilizer used in the base fertilizer.

[0025] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for intercropping multiple forage grasses in citrus orchards, which has the following beneficial effects:

[0026] This invention achieves multiple synergistic benefits through the scientific mixed sowing and standardized management of four forage grasses: ryegrass, white clover, gnaphalium affine, and milkvetch. These grasses offer complementary root systems at varying depths, effectively loosening the soil, improving soil structure, and reducing soil erosion. Combined with bio-fertilizers and forage return to the field, soil organic matter content increases. Furthermore, the legume forage grasses' outstanding nitrogen-fixing ability significantly reduces the amount of chemical fertilizer used in citrus orchards and continuously improves soil fertility. The mixed forage grasses grow rapidly, achieving full orchard coverage within 1-2 months, improving the control rate of noxious weeds, and eliminating the need for additional fertilizers throughout the entire process. Spraying chemical herbicides can reduce pesticide residues, protect the orchard's ecological environment, and reduce the cost of manual weeding. Simultaneously, the complementary growth characteristics of pasture grasses allow for year-round coverage in citrus orchards, providing cooling and moisture retention in summer and frost protection for roots in winter, optimizing the root growth environment for citrus trees. This intercropping model is suitable for various types of citrus orchards on flat land, gentle slopes, and hills, as well as citrus trees of different ages and varieties. Furthermore, this intercropping model optimizes the orchard's micro-ecological environment, reduces the incidence of citrus diseases and pests, promotes the robust growth of citrus trees, increases citrus yield per acre, significantly improves the rate of high-quality fruit, and truly constructs a green, efficient, and sustainable citrus ecological planting system. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1

[0028] Changsha Plain Rock Sugar Orange Orchard Intercropping with Pasture Experiment

[0029] The experiment was conducted in a standardized citrus orchard on flat land in Changsha, Hunan Province. The tested variety was 3-year-old Bing Tang Orange. The plant spacing was 3m × 4m. The soil layer thickness was 65cm, the soil pH was 5.6, and the initial soil organic matter content was 1.21%. The terrain was flat and the irrigation and drainage were convenient. The experimental group was set up with 3 mu (0.067 hectares) using the intercropping method of this invention, and the control group was set up with 3 mu (0.067 hectares) using traditional clean cultivation and bare land management. The growth of citrus trees, soil conditions, and conventional management measures were completely identical in the two groups.

[0030] Intercropping specific operations:

[0031] (1) Orchard pretreatment: Clean up dead branches, weeds and diseased plant debris in the orchard, retain a 40cm clear cultivation strip inside the drip line of the tree canopy, and shallow cultivate 12cm between rows; apply 280kg of decomposed sheep manure, 15kg of calcium magnesium phosphate fertilizer and 6kg of bio-fertilizer per mu, and dig drainage ditches 15cm deep and 20cm wide; the bio-fertilizer used has an effective live bacteria count of 520 million / g, and the components are Bacillus subtilis inoculum 28%, Bacillus spp. gelatinous inoculum 22%, Azotobacter chrysotile inoculum 18%, and Phosphorus and potassium solubilizing inoculum 12%, with the remainder being a carrier auxiliary material of decomposed humic acid, wood ash and fine sand mixed in a ratio of 3:2:1;

[0032] (2) Seed treatment: The total amount of mixed seeds per mu is 4.0 kg, with the following ratio: 35% ryegrass, 22% white clover, 18% fodderwort, and 25% milk vetch; the seeds are dried for 6 hours, and the milk vetch and white clover are soaked in 42℃ warm water for 2.5 hours, and mixed with 0.8% of the seed weight of rhizobium inoculant; the ryegrass, fodderwort, fine sand, and wood ash are mixed in a ratio of 1:4:1.

[0033] (3) Sowing: Sow in early October at an air temperature of 20℃ and a soil moisture content of 65%; sow in rows with a spacing of 25cm and a sowing depth of 0.8cm, cover with 0.5cm of fine soil and press lightly, and water thoroughly within 24 hours to settle the roots;

[0034] (4) Seedling management: Thin and replant seedlings 9 days after emergence and when the seedlings are 4cm tall, with a plant spacing of 7cm; apply 180kg of well-rotted and diluted biogas slurry per mu; manually remove noxious weeds; and drain water in time during the rainy season.

[0035] (5) Management during the growing season: spray 0.25% potassium dihydrogen phosphate + 0.1% brassinolide foliar fertilizer before the low temperature in winter; cut the grass when it exceeds 45cm in spring to control its growth, do not spray herbicides throughout the process, and maintain the routine management of citrus.

[0036] (6) Cutting and returning to the field: When the grass plants are 35cm tall, cut them for the first time, leaving a stubble of 9cm; in April of the following year, when the milkvetch is in full bloom and the grass has fallen over, cut the whole garden. Cut the grass three times a year; cover the tree basin with 70% of the grass (7cm thick), and turn 30% into the soil to a depth of 12cm. Apply 8kg of quicklime per mu.

[0037] (7) Water and fertilizer regulation: Reduce the amount of nitrogen fertilizer applied to citrus by 30%, and increase the application of potassium sulfate compound fertilizer by 18 kg and decomposed rapeseed cake by 100 kg per mu; the soil moisture content should be ≤65% during the rainy season and drip irrigation should be used to replenish the moisture content to 65% during the dry season; loosen the soil between rows by 10 cm every year, and apply 8 kg of biological fertilizer per mu after 3 years of continuous intercropping.

[0038] Experimental results and data:

[0039] After 12 months of continuous planting, soil and related indicators of the sugar oranges were measured, and the results are shown in the table below:

[0040] Example 2

[0041] Hilly rock sugar orange orchard intercropping with pasture experiment

[0042] The experiment was conducted in the hilly citrus-producing area of ​​Huaihua, Hunan Province. The tested variety was 4-year-old Bing Tang orange. The slope of the orchard was 12°, the soil layer thickness was 55cm, the soil pH was 5.8, and the initial soil organic matter content was 1.03%. The experimental group (2 mu) used the intercropping method of this invention, while the control group (2 mu) used a single ryegrass intercropping method. The site conditions and management measures of the two groups were the same.

[0043] Intercropping procedure: Sow a total of 4.5 kg of mixed seeds per mu, with a ratio of 36% ryegrass, 21% white clover, 17% bulrush and 26% milkvetch; shallowly cultivate between rows to 10 cm, and apply 320 kg of decomposed cow manure, 16 kg of calcium magnesium phosphate fertilizer and 7 kg of bio-fertilizer per mu; sow in mid-October, and follow the same steps as in Example 1 for seedling stage, growth stage, mowing and returning to the field, and water and fertilizer management.

[0044] Experimental results and data:

[0045] After the experiment, soil, sugar orange, and ecological indicators were measured. The data comparison results between the experimental group and the control group intercropped with mono-ryegrass are shown in the table below:

[0046]

[0047] As can be seen from the data in the table above, the overall benefits of the experimental group are far superior to those of the control group intercropped with single ryegrass. The intercropping method of this invention is suitable for the planting needs of hilly rock sugar orange orchards, and has outstanding effects in fertilization, weed control, yield increase and stress resistance.

[0048] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of interplanting a plurality of grasses in a citrus grove, the method comprising: The forage grass is a mixture of four varieties: ryegrass, white clover, grubsgrass, and milkvetch. The total amount of mixed seeds is 3.8-5.2 kg / mu, and the weight ratio of each grass species is as follows: ryegrass 32%-38%, white clover 21%-24%, grubsgrass 16%-19%, and milkvetch 22%-26%.

2. A method of interplanting a plurality of grasses in a citrus grove according to claim 1, characterized in that, Includes the following steps: Step 1: Orchard Pretreatment Select a citrus orchard with good drainage and light, thoroughly clean up dead branches, fallen leaves, diseased and damaged plants and weeds in the orchard, retain a 30-50cm clean-cultivation and root protection strip inside the drip line of the citrus canopy, shallow cultivate between rows and apply well-rotted farmyard manure, calcium magnesium phosphate fertilizer and bio-fertilizer as base fertilizer, and dig drainage ditches. Step 2: Pretreatment of forage seeds Place the mixed forage seeds in the sun to dry for 5-8 hours. Soak the seeds of milkvetch and white clover in warm water, drain them, and mix them with rhizobium inoculant at 0.5%-1% of the seed weight. Mix the seeds of ryegrass and clematis with fine sand and wood ash in a mass ratio of 1:4:1 and set aside. Step 3: Precision Sowing The sowing period is from late September to late October in autumn. The ambient temperature should be stable at 14-26℃ and the soil moisture content should be maintained at 60%-70%. Sowing should be done in rows. After sowing, cover with fine soil and lightly press it down. Water thoroughly within 24 hours to settle the roots. Step 4: Seedling Management Thinning and replanting should be carried out 7-10 days after the grass seedlings emerge and when the seedlings are 3-6cm tall. Remove diseased, weak, and clump-forming seedlings, and maintain a plant spacing of 6-9cm. Replant seedlings in areas with missing seedlings in a timely manner. After thinning, apply fertilizer to promote seedling growth, remove weeds manually, and drain water in a timely manner during the rainy season to prevent root rot. Step 5: Growth Period Management Five to seven days before the arrival of winter low temperatures, spray a foliar fertilizer consisting of 0.2%-0.3% potassium dihydrogen phosphate and 0.1% brassinolide. During the vigorous growth period of pasture in spring, cut pasture plants that are taller than 45cm, without spraying herbicides. Routine watering, fertilization, and pest and disease control operations for citrus trees can continue as usual. Step Six: Harvesting and Returning Pasture to the Field When the ryegrass and white clover plants reach a height of 30-40cm, the first cut should be made, avoiding the peak flowering period and physiological fruit drop period of citrus. In March-April of the following year, when the milkvetch is in full bloom and the clematis has completely fallen over, the entire orchard should be cut. Cut 2-3 times a year, with the last cut completed 10-15 days after the citrus harvest. Step 7: Water and Fertilizer Regulation After intercropping with pasture, the amount of nitrogen fertilizer applied to citrus trees is reduced by 25%-35%, while potassium fertilizer and organic fertilizer are applied more frequently. Watering is reduced during the rainy season and drip irrigation is used to supplement water during the dry season. After 2-3 years of continuous intercropping, bio-fertilizer is applied throughout the orchard to maintain the soil.

3. A method of interplanting a plurality of grasses in a citrus grove according to claim 2, wherein, In Step 1, the soil layer thickness in the citrus orchard should be ≥50cm, and the soil pH value should be 5.0-7.0; the shallow cultivation depth between rows should be 10-15cm; the application rate of well-rotted farmyard manure should be 250-350kg / mu, the application rate of calcium magnesium phosphate fertilizer should be 12-18kg / mu, and the application rate of bio-fertilizer should be 5-8kg / mu; the drainage ditch should be 12-18cm deep and 15-25cm wide.

4. A method for intercropping multiple forage grasses in a citrus orchard according to claim 3, characterized in that, The bio-fertilizer has an effective live bacteria count ≥ 500 million / g and, by weight percentage, is composed of 25%-30% Bacillus subtilis inoculant, 20%-25% Bacillus spp. inoculant, 15%-20% Azotobacter chrysotile inoculant, 10%-15% phosphorus-solubilizing and potassium-solubilizing inoculant, and the remainder being carrier additives. The carrier additives are a mixture of well-rotted humic acid, wood ash, and fine sand in a mass ratio of 3:2:

1.

5. A method for intercropping multiple forage grasses in a citrus orchard according to claim 2, characterized in that, The warm water soaking mentioned in step two refers to soaking the seeds in warm water at 40-45℃ for 2.5-3 hours.

6. A method for intercropping multiple forage grasses in a citrus orchard according to claim 2, characterized in that, In step three, the row spacing for sowing is 22-28cm, the sowing depth is 0.6-1.0cm, and after sowing, cover with 0.4-0.6cm of fine soil.

7. A method for intercropping multiple forage grasses in a citrus orchard according to claim 2, characterized in that, The seedling-promoting fertilizer mentioned in step four is a well-rotted and diluted biogas slurry, applied at a rate of 150-200 kg / mu.

8. A method for intercropping multiple forage grasses in a citrus orchard according to claim 2, characterized in that, In step six, the stubble height should be 8-11cm. Small machinery or manual cutting should be used to avoid damaging the citrus trees. By weight, 70% of the fresh forage should be used to cover the tree basin and between rows after cutting, with a covering thickness of 5-9cm. 30% of the forage should be turned into the soil to a depth of 10-15cm as green manure. After turning, 5-10kg / mu of quicklime should be spread to adjust the soil pH.

9. A method for intercropping multiple forage grasses in a citrus orchard according to claim 2, characterized in that, The potassium fertilizer mentioned in step seven is potassium sulfate compound fertilizer, with an application rate of 15-20 kg / mu; the organic fertilizer is well-rotted cake fertilizer, with an application rate of 80-120 kg / mu; during the rainy season, water should be controlled to prevent flooding, and the soil moisture content should be ≤65%; during the dry season, drip irrigation should be used to supplement water and maintain the soil moisture content at 60%-70%; the soil between rows should be loosened to a depth of 8-12 cm annually in conjunction with returning pasture to the field; and the application rate of bio-fertilizer is 6-10 kg / mu.

10. A method for intercropping multiple forage grasses in a citrus orchard according to claim 1, characterized in that, The citrus orchard refers to an area with young trees aged 1-15 years or trees in their prime fruiting period. The citrus orchard is located on flat land or gently sloping hills with a slope of ≤15°. The applicable citrus varieties are any one of Wogan, Sugar Orange, Navel Orange, Honey Orange, and Rock Sugar Orange.

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