Method for restoring citrus trees and its use

Abstract

The present application relates to the technical field of resource utilization of fruit tree branches, and provides a method for returning citrus branches to the orchard, which comprises the following steps: (1) crushing and fermenting the pruned citrus branches, and mixing the branches with organic fertilizer to obtain material A; (2) digging a ditch along a direction parallel to the tangent of the tree crown drip line; and (3) applying the material A obtained in the step (2) into the ditch, and then covering the ditch with soil. The method for returning citrus branches to the orchard can significantly improve the diversity of arbuscular mycorrhizal fungi and the stability of the community structure in the soil, and promote more arbuscular mycorrhizal fungi to act on the rhizosphere soil and root hairs of citrus, so as to effectively improve the physicochemical properties of the soil and promote the growth and development of citrus. The method for returning citrus branches to the orchard is a resource utilization of waste, and can better promote the green, low-carbon, efficient and sustainable development of the citrus industry.

Description

Technical Field

[0001] This invention relates to the field of fruit tree branch resource utilization technology, and in particular to a method for returning citrus branches to orchards and its application. Background Technology

[0002] Citrus is one of the world's most important economic crops, the world's largest fruit category, and the most widely cultivated and economically significant fruit tree in southern my country. However, with the development of the citrus industry, more and more problems have arisen, especially the increasingly prominent issue of pruning in citrus-producing areas. Current surveys have found that per 667m²... 2 The annual pruning volume of mature citrus orchards is approximately 900-1000 kg (fresh weight). This amount can be significantly increased with practices such as top grafting, thinning, and regeneration. However, most fruit growers habitually discard or pile these branches indiscriminately in the orchard, creating breeding grounds for pests and diseases and fire hazards. This negatively impacts the ecological environment and severely hinders the sustainable development of the citrus industry.

[0003] The mutualistic symbiosis between plants and microorganisms is a common phenomenon in nature and plays an important role in maintaining the function of ecosystems. Among them, arbuscular mycorrhizal fungi (AMF) form the most widespread symbiotic relationships with plants, with about 80% of terrestrial plants forming arbuscular mycorrhizae, making them a very important type of functional microorganism in the soil.

[0004] For the reasons mentioned above, it is essential to find a better way to address the problem of citrus pruning and promote a healthy "symbiotic relationship" within the citrus orchard ecosystem. Summary of the Invention

[0005] The purpose of this invention is to provide a method for returning citrus branches to the orchard. This method can significantly improve the diversity and community structure stability of arbuscular mycorrhizal fungi in the soil, encourage more arbuscular mycorrhizal fungi to act on the rhizosphere soil and root hairs of citrus trees, thereby effectively improving the physical and chemical properties of the soil and promoting the growth and development of citrus trees.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for returning citrus branches to an orchard, comprising the following steps:

[0008] (1) Crush and ferment the pruned citrus branches and mix them with organic fertilizer to obtain material A;

[0009] (2) Dig a trench parallel to the tangent of the tree canopy drip line;

[0010] (3) Apply the obtained material A into the trench described in step (2), and then cover it with soil.

[0011] Preferably, the mass ratio of the citrus branches to the organic fertilizer in step (1) is (1.3-3):1.

[0012] Preferably, the citrus branches are shredded to a length of 2-5 cm.

[0013] Preferably, the fermentation method in step (1) is pile fermentation, and the height of the fermentation pile is 50-80cm.

[0014] Preferably, the fermentation pile is turned over when the temperature is 60-70°C at a depth of 8-15 cm inside the surface of the portion above 1 / 2 of the pile height, and the pile is turned over 2-3 times.

[0015] Preferably, the fermentation time in step (1) is 10-18 days, and the relative humidity during fermentation is 50-65%.

[0016] Preferably, the organic fertilizer in step (1) is sheep manure or chicken manure.

[0017] Preferably, the trench in step (2) is 0-10cm inside or outside the tangent of the tree canopy drip line; the depth of the trench is 18-22cm; and the width of the trench is 12-18cm.

[0018] As a preferred option, the application rate of material A in step (3) is 3-8 tons / acre.

[0019] This invention provides the application of the method for returning citrus branches to the orchard in improving the diversity of arbuscular mycorrhizal fungi and the stability of community structure in the soil.

[0020] The present invention also provides the application of the method for returning citrus branches to the orchard in improving the physical and chemical properties of soil.

[0021] The present invention also provides the application of the method for returning citrus branches to the orchard in promoting the growth and development of citrus.

[0022] By adopting the above technical solution, the present invention has the following beneficial effects:

[0023] 1. In this invention, citrus roots can form a symbiotic relationship with arbuscular mycorrhizal fungi (AMF). AMF hyphae are aseptate hyphae. AMF infects the cortex of plant roots, forming hyphae between cortical cells and arbuscular and vesicular structures within the cortical cells. It can transport soil nutrients up to several meters away to the symbiotic plant through its hyphae, while simultaneously maintaining its survival by utilizing organic matter synthesized by the plant. The citrus branches returned to the orchard in this invention create a suitable soil environment, promoting AMF growth and reproduction, significantly increasing the diversity and community stability of arbuscular mycorrhizal fungi in the soil. This, in turn, allows more AMF to act on the citrus root hairs. The symbiotic relationship between the two enables the root hairs to absorb more phosphorus and other nutrients, promoting citrus growth and even improving the quality and yield of citrus.

[0024] 2. The citrus branches described in the technical solution of the present invention, after being fermented and returned to the orchard, can effectively increase the soil organic matter content and improve soil fertility. At the same time, it also promotes more AMF to act on the soil in the rhizosphere of citrus trees, thereby improving the physical and chemical properties of the soil.

[0025] 3. The resource utilization of citrus branches in the technical solution described in this invention is of great significance for promoting the green, low-carbon, efficient and sustainable development of the citrus industry. Detailed Implementation

[0026] This invention provides a method for returning citrus branches to an orchard, comprising the following steps:

[0027] (1) Crush and ferment the pruned citrus branches and mix them with organic fertilizer to obtain material A;

[0028] (2) Dig a trench parallel to the tangent of the tree canopy drip line;

[0029] (3) Apply the obtained material A into the trench described in step (2), and then cover it with soil.

[0030] In this invention, citrus branches pruned from the orchard are pulverized and then fermented. The pulverized branches are preferably 2-5 cm in length, more preferably 2.5-4.5 cm, and even more preferably 3-4 cm. The fermentation method is pile fermentation; the pulverized citrus branches are directly piled into a fermentation pile and covered with a plastic film for fermentation. The height of the fermentation pile is preferably 50-80 cm, more preferably 55-75 cm, and even more preferably 65 cm. Preferably, the pile is turned when the temperature is 60-70°C at a depth of 8-15 cm within the surface of the portion above half the pile's height. The turning is preferably performed 2-3 times, more preferably 2 times. The fermentation time is preferably 10-18 days, more preferably 12-17 days, and even more preferably 15-16 days. The relative humidity during fermentation is preferably 50-65%, more preferably 52-62%, and even more preferably 58-60%.

[0031] In this invention, fermented citrus branches are mixed evenly with organic fertilizer to obtain material A. The preferred mass ratio of the citrus branches to the organic fertilizer is (1.3-3):1, more preferably (1.5-2.2):1, and even more preferably 1.8:1. The organic fertilizer used in this invention is sheep manure or chicken manure, more preferably sheep manure. The organic fertilizer used in this invention contains a large amount of grass fiber, has no pungent odor, and compared with other manures of the same mass, sheep manure has a higher content of organic acids and nitrogen, phosphorus, and potassium. The grass fiber it contains can loosen the soil, is relatively mild and does not easily damage roots, and has a longer-lasting fertilizer effect. The organic matter in sheep manure can also provide nutrients for soil microorganisms, promoting their growth and reproduction.

[0032] In this invention, trenches are dug along a direction parallel to the tangent of the tree canopy drip line, preferably using a north-south first, then east-west method. Preferably, the trenches can be dug along the tangent of the tree canopy drip line, using a north-south first, then east-west method; they can be dug within a direction parallel to the tangent of the tree canopy drip line, using a north-south first, then east-west method; and they can be dug outside a direction parallel to the tangent of the tree canopy drip line, using a north-south first, then east-west method. The trench shape is preferably square. The trench is preferably 0-10cm inside or outside the tangent of the tree canopy drip line; the trench depth is preferably 18-22cm, more preferably 19-21cm, and even more preferably 20cm; the trench width is preferably 12-18cm, more preferably 13-16cm, and even more preferably 15cm. In this invention, the area around the drip line has the highest concentration of root hairs.

[0033] In this invention, the prepared material A is applied into the above-mentioned trench. The preferred amount of material A is 3-8 tons / mu, more preferably 4-7 tons / mu, and even more preferably 6 tons / mu.

[0034] The present invention also provides the application of the method for returning citrus branches to the orchard in improving the diversity of arbuscular mycorrhizal fungi and the stability of community structure in the soil.

[0035] The present invention also provides the application of the method for returning citrus branches to the orchard in improving the physical and chemical properties of soil.

[0036] The present invention also provides the application of the method for returning citrus branches to the orchard in promoting the growth and development of citrus.

[0037] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0038] Example 1

[0039] A method for restoring citrus branches to a garden, the steps are as follows:

[0040] (1) After the citrus branches pruned from the citrus orchard are crushed to a length of 3cm, they are piled into a fermentation pile with a height of 65cm. The pile is covered with plastic film for fermentation treatment. Fermentation is carried out at 60% relative humidity for 15 days. During this period, the pile is turned over twice when the temperature is 65℃ at 15cm inside the surface of the part above 1 / 2 of the height of the fermentation pile.

[0041] (2) Mix the fermented citrus branches and sheep manure evenly at a mass ratio of 1.8:1 to obtain material A;

[0042] (3) Dig trenches along the drip line of the tree canopy, first in the north-south direction and then in the east-west direction. The trenches are square in shape, with a depth of 20cm and a width of 15cm.

[0043] (4) Apply the obtained material A into the ditch at a rate of 6 tons / acre, and then backfill with soil.

[0044] Example 2

[0045] A method for restoring citrus branches to a garden, the steps are as follows:

[0046] (1) After the citrus branches pruned from the citrus orchard are crushed to a length of 5cm, they are piled into a fermentation pile with a height of 80cm. The pile is covered with plastic film for fermentation treatment. Fermentation is carried out at a relative humidity of 65% for 10 days. During this period, the pile is turned over twice when the temperature is 60℃ at a depth of 10cm inside the surface of the part above 1 / 2 of the height of the fermentation pile.

[0047] (2) Mix the fermented citrus branches and sheep manure evenly at a mass ratio of 1.5:1 to obtain material A;

[0048] (3) Dig a trench 10cm inside the direction parallel to the tangent of the tree canopy drip line, first in the north-south direction and then in the east-west direction. The trench should be square in shape, 20cm deep and 15cm wide.

[0049] (4) Apply the obtained material A into the ditch at a rate of 3 tons / acre, and then backfill with soil.

[0050] Example 3

[0051] A method for restoring citrus branches to a garden, the steps are as follows:

[0052] (1) After the citrus branches pruned from the citrus orchard are crushed to a length of 2.5cm, they are piled into a fermentation pile with a height of 55cm. The pile is covered with plastic film for fermentation treatment. Fermentation is carried out at 50% relative humidity for 18 days. During this period, the pile is turned over twice when the temperature is 70℃ at 15cm inside the surface of the part above 1 / 2 of the height of the fermentation pile.

[0053] (2) Mix the fermented citrus branches and chicken manure evenly at a mass ratio of 2.2:1 to obtain material A;

[0054] (3) Dig a trench 10cm away from the direction parallel to the tangent of the tree canopy drip line, first in the north-south direction and then in the east-west direction. The trench is square in shape, 20cm deep and 15cm wide.

[0055] (4) Apply the obtained material A into the ditch at a rate of 8 tons / acre, and then backfill with soil.

[0056] Example 4

[0057] A method for restoring citrus branches to a garden, the steps are as follows:

[0058] (1) After the citrus branches pruned from the citrus orchard are crushed to a length of 3cm, they are piled into a fermentation pile with a height of 65cm. The pile is covered with plastic film for fermentation treatment. Fermentation is carried out at 60% relative humidity for 15 days. During this period, the pile is turned over twice when the temperature is 65℃ at 15cm inside the surface of the part above 1 / 2 of the height of the fermentation pile.

[0059] (2) Mix the fermented citrus branches and sheep manure evenly at a mass ratio of 1.8:1 to obtain material A;

[0060] (3) Dig trenches along the drip line of the tree canopy, first in the north-south direction and then in the east-west direction. The trenches are square in shape, with a depth of 18cm and a width of 12cm.

[0061] (4) Apply the obtained material A into the ditch at a rate of 6 tons / acre, and then backfill with soil.

[0062] Comparative Example 1

[0063] A method for restoring citrus branches to a garden, the steps are as follows:

[0064] (1) Shred the citrus branches pruned from the citrus orchard into 3cm lengths;

[0065] (2) Dig trenches along the drip line of the tree canopy, first in the north-south direction and then in the east-west direction. The trenches are square in shape, with a depth of 20cm and a width of 15cm.

[0066] (3) Apply the crushed citrus branches into the trench at a rate of 6 tons / acre, and then backfill with soil.

[0067] Comparative Example 2

[0068] A method for restoring citrus branches to a garden, the steps are as follows:

[0069] (1) After the citrus branches pruned from the citrus orchard are crushed to a length of 3cm, they are piled into a fermentation pile with a height of 65cm. The pile is covered with plastic film for fermentation treatment. Fermentation is carried out at 60% relative humidity for 15 days. During this period, the pile is turned over twice when the temperature is 65℃ at 15cm inside the surface of the part above 1 / 2 of the height of the fermentation pile.

[0070] (2) Dig trenches along the drip line of the tree canopy, first in the north-south direction and then in the east-west direction. The trenches are square in shape, with a depth of 20cm and a width of 15cm.

[0071] (3) Apply the fermented citrus branches into the trench at a rate of 6 tons / acre, and then backfill with soil.

[0072] Comparative Example 3

[0073] A method for restoring citrus branches to a garden, the steps are as follows:

[0074] (1) After the citrus branches pruned from the orchard are crushed to a length of 3cm, they are piled into a fermentation pile with a height of 65cm and covered with plastic film for fermentation treatment. Fermentation is carried out for 15 days at a relative humidity of 30%.

[0075] (2) Mix the fermented citrus branches and sheep manure evenly at a mass ratio of 1.8:1 to obtain material A;

[0076] (3) Dig trenches along the drip line of the tree canopy, first in the north-south direction and then in the east-west direction. The trenches are square in shape, with a depth of 20cm and a width of 15cm.

[0077] (4) Apply the obtained material A into the ditch at a rate of 6 tons / acre, and then backfill with soil.

[0078] Comparative Example 4

[0079] A method for restoring citrus branches to a garden, the steps are as follows:

[0080] (1) After the citrus branches pruned from the citrus orchard are crushed to a length of 3cm, they are piled into a fermentation pile with a height of 65cm. The pile is covered with plastic film for fermentation treatment. Fermentation is carried out at 60% relative humidity for 15 days. During this period, the pile is turned over twice when the temperature is 65℃ at 15cm inside the surface of the part above 1 / 2 of the height of the fermentation pile.

[0081] (2) Mix the fermented citrus branches and sheep manure evenly at a mass ratio of 0.5:1 to obtain material A;

[0082] (3) Dig trenches along the drip line of the tree canopy, first in the north-south direction and then in the east-west direction. The trenches are square in shape, with a depth of 40cm and a width of 15cm.

[0083] (4) Apply the obtained material A into the ditch at a rate of 2 tons / acre, and then backfill with soil.

[0084] Experimental Example 1

[0085] The citrus variety selected was Quzhou Ponkan, and the research site was the open-field citrus research and experimental base of Quzhou University. Five-year-old Quzhou Ponkan trees were used, with a row spacing of 4m and a plant spacing of 3m. Six healthy and uniform Ponkan experimental plots were randomly selected from the experimental base, with five Ponkan trees planted in each plot. Each experimental plot adopted the following methods: control group (no orchard return), Example 1, and Comparative Examples 1-4.

[0086] After removing the topsoil, take a 20-30cm soil layer and collect root and rhizosphere soil samples from the test plants every 3 months for later use.

[0087] Physicochemical properties of rhizosphere soil from different treatment groups of citrus were analyzed. Organic matter content was determined using a TOC analyzer, available phosphorus and alkaline nitrogen were determined using a continuous flow analyzer after soil digestion, and available potassium was determined using inductively coupled plasma atomic emission spectrometry. The results are shown in Table 1.

[0088] Table 1. Physicochemical properties of rhizosphere soil from different groups of citrus trees.

[0089]

[0090] As can be seen from Table 1, the physicochemical properties of the citrus rhizosphere soil in Example 1 of this invention are relatively the best, with a significant increase in organic matter, alkaline nitrogen, available phosphorus, and available potassium in the soil.

[0091] Experimental Example 2: Identification and Analysis of AMF in Citrus Rhizosphere Soil

[0092] (I) Isolation and morphological identification of AMF spores

[0093] The wet sieving-decantation-sucrose centrifugation method was employed. 10g of each of the above-mentioned air-dried soil samples were weighed and placed in a food processor with 500mL of water. After high-speed rotation for 5 seconds, the samples were sequentially passed through standard soil sieves of 0.8mm, 0.25mm, and 0.038mm. The soil was repeatedly washed and sieved four times. The sieve contents were repeatedly rinsed with water until no soil particles remained. The material from the upper sieve was transferred to a petri dish for direct observation under a stereomicroscope. The residue from the lower sieve was transferred to a 50mL centrifuge tube containing a 20-60% sucrose gradient, centrifuged, and the supernatant was discarded. After washing, the samples were observed under a stereomicroscope for the color, size, mycelial characteristics, and morphology of AMF spores. Analysis and comparison were performed to classify and identify AMF cultivation resources.

[0094] Five genera of AMF strains were isolated, including *Glomus*, *Acaulospora*, *Entrophospora*, *Scutellospora*, and *Paraglomus*. Species included are: *Glomus* sp. VTX00090, *Glomus* sp. VTX00248, *Glomus* sp. VTX00362, *Glomus* sp. VTX00399, *Glomus* sp. VTX00403, *Glomus*. *intraradices*, *Paraglomus* sp. VTX00238, *Glomus mossear*, *Scutellospora* sp. VTX00041, *Acaulospora* sp. VTX00024, *Entrophospora baltica*, and *Acaulospora brieticulata*.

[0095] In all treatment groups, the genus Glomus had the highest number and variety of species in the rhizosphere soil.

[0096] (II) Analysis of AMF Diversity and Community Structure

[0097] The α diversity of AMF in the rhizosphere soil of citrus in different treatment groups was determined. α diversity can be used to reflect the abundance and diversity of species in the samples. Diversity indicators include Shannon index, Simpson index, ACE index and OUT index.

[0098] Table 2. AMF diversity index in rhizosphere soil of different treatment groups

[0099] Group Shannon Simpson ACE OUT control group 1.85 0.40 138.61 489.32 Example 1 2.78 0.24 217.05 813.76 Comparative Example 1 2.15 0.35 156.42 601.34 Comparative Example 2 2.34 0.31 179.16 690.57 Comparative Example 3 2.46 0.29 198.35 725.23 Comparative Example 4 2.59 0.26 209.47 792.06

[0100] It is known that a higher Shannon index and a lower Simpson index indicate higher community diversity. Table 2 shows that after the citrus branch return treatment, there were certain changes in AMF diversity and community structure in the citrus rhizosphere soil, with a significant increase in both the types and quantities of AMF species. Among these, the changes in AMF abundance and diversity were most pronounced in the rhizosphere soil of Example 1 group, with the highest Shannon index and the lowest Simpson index, indicating that Example 1 group had the highest community diversity.

[0101] (III) AMF Infection Rate Analysis

[0102] Fine roots from surviving plants were collected from each of the above treatments. Thirty (1 cm) fine root segments with root tips were randomly selected from each plant, treated with FAA fixative for at least 24 hours, and stored for later use. The AMF infection status was detected using Phillips' method (PHILLIPS JM, HAYMAN DS. Improved procedures for clearing roots and staining parasitic and vesicular-arbuscular mycorrhizal fungi for rapid assessment of infection[J]. Trans Br Mycol Soc, 1970, 55(1):158–161,IN16–IN18. doi:10.1016 / S0007-1536(70)80110-3.). The infection rate can be used as a direct indicator of whether AMF is symbiotic with the citrus rhizosphere.

[0103] Mycorrhizal infection rate (%) = Length of root segment infected with AMF / Total length of root segments tested × 100%

[0104] Table 3. Rhizosphere mycorrhizal infection status in different treatment groups

[0105]

[0106] As shown in Table 3, the AMF infection rate in the Example Group and the Comparative Group was significantly higher than that in the Control Group, with the highest AMF infection rate in Example 1 Group. This indicates that citrus roots can form a good symbiotic relationship with AMF. AMF infection promotes, for example, root growth and development, increases root surface area, volume and number of branches, expands the distribution range of the root system, and thus increases the absorption area of ​​nutrients and water for citrus, enabling it to obtain more nutrients, promote citrus growth, and improve the quality and yield of citrus.

[0107] As can be seen from the above embodiments and experimental examples, the citrus branch return method of the present invention significantly improves the diversity and community structure stability of arbuscular mycorrhizal fungi in the soil, enabling more arbuscular mycorrhizal fungi to act on the soil and root hairs in the rhizosphere of citrus, effectively improving the physical and chemical properties of the soil, and promoting the growth and development of citrus.

[0108] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for returning citrus branches to an orchard, characterized in that, Includes the following steps: (1) Crush and ferment the pruned citrus branches and mix them with organic fertilizer to obtain material A; (2) Dig a trench parallel to the tangent of the tree canopy drip line; (3) Apply material A into the trench described in step (2), and then cover it with soil. The mass ratio of the citrus branches to the organic fertilizer in step (1) is (1.3-3):1; The fermentation method described in step (1) is pile fermentation, and the height of the fermentation pile is 50-80cm; When the temperature at a depth of 8-15 cm within the surface of the part above 1 / 2 of the height of the fermentation pile reaches 60-70℃, the pile is turned over 2-3 times. The trench described in step (2) is 0-10cm inside or outside the tangent of the tree canopy drip line; the depth of the trench is 18-22cm; and the width of the trench is 12-18cm. Step (3) The application rate of material A is 3-8 tons / mu.

2. The method for returning the garden to its original state according to claim 1, characterized in that, The mass ratio of the citrus branches to the organic fertilizer in step (1) is (1.3-3):1; The citrus branches are shredded to a length of 2-5cm.

3. The method for returning the garden to its original state according to claim 1, characterized in that, The fermentation time in step (1) is 10-18 days, and the relative humidity during fermentation is 50-65%.

4. The method for returning the garden to its original state according to claim 1, characterized in that, The organic fertilizer mentioned in step (1) is sheep manure or chicken manure.

5. The method for returning citrus branches as described in any one of claims 1-4 is used to improve the diversity of arbuscular mycorrhizal fungi and the stability of community structure in soil.

6. The application of the method for returning citrus branches as described in any one of claims 1-4 in improving the physical and chemical properties of soil.

7. The application of the method for returning citrus branches as described in any one of claims 1-4 in promoting the growth and development of citrus.

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