CN106922242A - A soil improvement method for citrus orchards - Google Patents

Abstract

The invention provides a soil improvement method for citrus orchards, comprising the following steps: S1: Select 1,000 square meters of hilly land, dry land and paddy fields with an altitude of less than 500 meters, relatively neat terrain, and a slope of hilly land not greater than 25 ^° . Land preparation as a citrus orchard for planting citrus, S2: carry out ditches to improve the soil and dig holes to improve the soil on the hills and dry lands, and carry out trenches to improve the soil, ditching and furrowing and dig holes to improve the soil on the paddy fields; the present invention is beneficial The effect is that the soil pH of the citrus orchard in the mountain gorge reservoir area is more suitable for the growth of citrus trees by improving the soil according to the different topographical characteristics of the citrus orchard. The water and fertilizer retention capacity of the middle soil, and the balance of water and fertilizer, meet and guarantee the demand for water and fertilizer of citrus trees. The citrus fruit setting rate is high, the fruit flavor is good, the yield and quality are greatly improved, and the local economic benefits are promoted.

Description

A soil improvement method for citrus orchards

technical field

The invention relates to the field of agricultural technology, in particular to a soil improvement method for citrus orchards.

Background technique

Citrus has many fruits and high yields, consumes a lot of fertilizer and water, and has higher requirements on soil conditions than ordinary crops. High-yield citrus orchards require deep, fertile, loose, and appropriate pH. It is difficult for ordinary cultivated land to meet this requirement, and barren hills and slopes are even worse. Soil improvement is to improve the soil, deepen the soil layer, increase fertility, adjust the pH of the soil, and lay a good foundation for the high yield of citrus. Many practices have proved that any citrus orchard that improves the soil well can easily obtain high-quality and high yields; any citrus orchard that does not improve the soil can hardly improve the yield and quality. Therefore, the construction of citrus orchards must improve the soil and lay a good foundation.

The Three Gorges Reservoir area is suitable for temperature and humidity, and it is the most suitable area for growing citrus in my country. The favorable conditions for the development of sweet orange production are rare in my country and even in Asia. However, this favorable condition has not been fully utilized at present. However, due to the The types of citrus cultivation gardens in China are mainly hilly land, dry land and paddy fields. The soil type is mainly purple soil. The soil pH is high, the soil layer is shallow, and the ability to retain water and fertilizer is poor. For a long time, the local area has not paid enough attention to the construction of citrus gardens. However, no standardized citrus orchard excavation and construction regulations have been formed according to the natural ecological conditions in the reservoir area. The scale of citrus production is not large, and the level of soil management before cultivation is not high, resulting in the lack of guarantee of water and fertilizer in the orchard, which seriously restricts the production of citrus and quality improvement.

Contents of the invention

In order to solve the current problems of high soil pH, shallow soil layer, poor water and fertilizer retention capacity, and low soil management level in citrus orchards in mountain gorge reservoir areas, the invention provides a soil improvement method for citrus orchards.

The present invention is achieved through the following technical solutions:

A method for improving soil in a citrus orchard, comprising the following steps:

S1: Select a 1,000-square-meter land preparation including hilly land, dry land and paddy fields with an altitude of less than 500 meters, relatively neat terrain, and a slope of hilly land not greater than 25° as an citrus orchard for planting citrus, within a linear range of ¹⁰ kilometers around the citrus orchard. No citrus quarantine pests and diseases;

S2: Carry out ditches and dig holes to improve the soil on the hilly land and dry land, and carry out ditches to improve the soil, open ditches and make furrows, and dig holes to improve the soil on the paddy fields;

The method for improving the soil in the hills and mountains in the citrus orchard is:

1) Trench reformation:

For gentle slopes in hilly and mountainous areas with slopes less than 10%, excavate ditches in the north-south direction on the slopes of the hilly and mountainous areas to improve the soil; Meters of soil width as a retaining wall for intercepting rainwater and sediment;

For the hilly and mountainous slopes with a slope greater than 10%, based on the construction of most of the terraces, the width of the terraces is an integral multiple of the planting row spacing, and the terraces are excavated along the contour line at a gradient of 0.3% to 0.5% according to the principle of contour. Digging ditches on the terraced land to improve the soil, the width of the terrace surface is greater than 2.5 meters, and the height of the ladder wall is less than 1.2 meters; the width of the trench is 1 to 1.5 meters, and the depth is 0.8 to 1 meter; If there is no soil improvement material, all backfill the plow layer soil;

2) Digging holes to improve soil:

According to the north-south direction and the east-west direction on the slope of the hills and mountains, according to the size of the citrus tree row spacing, the field planting grid is adopted to determine the position of the soil improvement hole on the slope of the hills and mountains; when the soil improvement hole is backfilled Bury soil improvement materials layer by layer, if there is no soil improvement material, all backfill the plow layer soil;

The soil improvement method to the dry land in the citrus orchard garden is:

Retain the existing terraces or terraces, adjust a small number of extremely irregular plots and special locations that affect citrus planting;

1) Trench reformation:

For blocky dry land on gentle slopes with a slope not exceeding 10%, the trenches are north-south, and the trench spacing is determined according to the row spacing of citrus trees;

For block dry land on a slope with a slope exceeding 10%, if the height difference between two adjacent plots is not greater than 70 cm, the trenches shall be excavated on the entire slope in the direction of parallel contour lines, and the same trench shall be Installed on different plots; if the height difference between two adjacent plots is greater than 70 centimeters, several trenches are dug on each plot according to row spacing, and the width of the plots is greater than 2.5 meters;

2) Digging holes to improve soil:

Described dry land is according to north-south direction, east-west plant direction, according to the size of citrus tree row spacing, determines the location of soil hole on the plot according to the field planting grid;

The method for improving the soil of the paddy field in the described citrus orchard is:

1) Trench reformation:

For flat land and paddy fields on gentle slopes where the slope is no more than 10%, the ditch adopts a north-south direction, and the distance between the ditch is determined according to the row spacing of citrus trees;

For terraced paddy fields on slopes with a slope of more than 10%, if the height difference between two adjacent paddy fields is not greater than 70 cm, the trenches shall be excavated in the direction of parallel contour lines on the entire slope, and the same trench Installed on different paddy fields; if the height difference between two adjacent paddy fields is greater than 70 centimeters, excavate several trenches according to row spacing on each paddy field, and the width of the plot is greater than 2.5 meters;

2) Ditching and furrowing:

For paddy fields with a depth of active soil layer greater than 50 cm, ditching and furrowing are carried out, and citrus is planted on the furrow surface; Citrus trees; for the paddy fields with good drainage performance, the width of the border surface is set to 10 meters to 20 meters, and 2 to 4 rows of citrus trees are planted; The depth is less than 1 meter;

3) Digging holes to improve soil:

For paddy fields with a depth of active soil layer greater than 80 cm and good soil water permeability under the plow bed, according to the north-south direction, east-west plant direction, and according to the row spacing of citrus trees, determine the digging position on the paddy field according to the planting grid.

Further, the trench is 1-1.5 meters wide and 0.8-1 meter deep, and the soil-improving hole is a circular pit with a diameter of 1.5 meters and a depth of 0.8-1 meter, or a circular nest with a length of 1.3-1.5 meters and a depth of 0.8 meters. A square nest of 1m to 1m; the topsoil, raw soil, and stones excavated during the excavation of the trench and the soil improvement hole are stacked separately.

Further, the soil improvement materials include fine soil improvement materials and rough soil improvement materials, and the fine soil improvement materials include farm manure and weeds, straw and branches that have been crushed or biogas fermented, or are the Fertilizer and a mixture of one or more materials in crushed or methane-fermented weeds, stalks, and branches; the rough soil improvement materials are weeds, straws, and branches that have not been crushed or methane-fermented .

Further, both the backfilling of the ditch and the backfilling of the soil improvement holes adopt the mixed filling method of soil and soil improvement materials: the soil improvement materials with a dry weight of 30-60 kg per cubic meter are filled into the trenches in 3 to 5 layers, The rough soil improvement material is placed in the bottom layer, the fine soil improvement material is placed in the middle and upper layers, and each layer is filled with soil at a depth of 0.15 to 0.20 meters; when backfilling, the soil at a depth of 0.6 to 0.8 meters is mixed with the rough soil improvement material and reach a depth of 0.6 to 0.8 meters, backfill the original 0.2 to 0.4 meters deep soil and reach a depth of 0.4 to 0.6 meters; mix the 0.6 to 0.8 meters deep soil with the finely modified soil material to reach a depth of 0.6 to 0.8 meters Backfill the original 0.2-0.4-meter-deep soil to a depth of 0.4-0.6 meters, backfill the original 0-0.2-meter topsoil to a depth of 0.2-0.4 meters until the trench is filled and higher than the original The ground is 0.3 to 0.4 meters, so that the filling depth of the topsoil and the soil improvement materials is in the distribution area of the citrus root system.

Further, if the soil pH value of the citrus orchard is higher than 7, according to the strength of alkalinity, add 3 to 10 kg of sulfur powder per cubic meter of backfill soil to reduce the soil pH value; Soil, add 1 to 3 kg of lime to each cubic meter of backfill soil to increase the pH of the soil.

Further, the row spacing of the citrus trees is 4-5.5 meters.

Further, if the groundwater level of the citrus orchard is below 1 meter, if the soil-forming parent material is difficult to weather, the height of the active soil layer is greater than 60 cm; if the soil-forming parent material is easy to weather, the height of the active soil layer is greater than 20 cm, and the height of the active soil layer is greater than 20 cm during the autumn drought period. The available water source is not less than 75 tons/mu.

The beneficial effect of the soil improvement method of a kind of citrus orchard field provided by the invention is:

By improving the soil according to the different terrain characteristics of the citrus orchard, the pH of the soil in the citrus orchard in the mountain gorge reservoir area is more suitable for the growth of citrus trees, the depth of the active soil layer is thickened, the soil is more fertile and loose, and the soil in the garden is improved. Excellent water and fertilizer retention capacity, water and fertilizer balance, meet and guarantee the demand for water and fertilizer of citrus trees, high fruit bearing rate of citrus, good fruit flavor, greatly improved yield and quality, and promoted local economic benefits.

Description of drawings

Fig. 1 is the excavation and backfill schematic diagram of ditch or soil improvement hole in a specific embodiment of the soil improvement method of citrus orchard field provided by the invention;

Fig. 2 is a schematic diagram of ditching paddy fields and making borders for planting citrus trees in the soil improvement method for citrus orchards provided by the present invention.

In the picture: 1-top soil, 2-raw soil, 30-coarse soil improvement material, 32-fine soil improvement material, 4-paddy field, 42-border surface Ⅰ, 44-border surface Ⅱ, 46-furrow ditch, 5 citrus trees .

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

detailed description

The soil improvement method of the citrus orchard field provided by the invention may further comprise the steps:

S1: Select a 1,000-square-meter plot of hilly land, dry land, and paddy fields at an altitude of less than 500 meters, relatively neat terrain, and a slope of hills and mountains not greater than 250 as an citrus orchard for planting citrus. Quarantine pests and diseases of citrus. Secondly, the groundwater level of citrus orchards is required to be below 1 meter. If the parent material of the soil is difficult to weather, the height of the active soil layer should be greater than 60 cm. If the parent material of the soil is easy to be weathered, the height of the active soil layer should be greater than 20 cm. Water sources can be used during the drought period in autumn Not less than 75 tons/mu.

S2: Improve the soil with ditches and dig holes for the hilly and dry lands, and improve the soil with trenches, open ditches and dig holes for the paddy fields.

The method for improving the soil in the hills and mountains in the citrus orchard is:

1) Trench reformation:

For gentle slopes in hilly and mountainous areas with a slope of less than 10%, excavate ditches along the north-south direction on the slopes of the hilly and mountainous areas to improve soil. When the direction of the trench is not parallel to the contour line, reserve 0.8 meters of soil width as a retaining wall at intervals to make the trench form a bamboo ditch to intercept rainwater and sediment and maintain the water and soil balance of the citrus orchard.

For hilly and mountainous slopes with a slope greater than 10%, the width of most of the terraces should be an integral multiple of the planting row spacing, and the terraces should be excavated along the contour line at a gradient of 0.3% to 0.5% according to the principle of contour. Dig ditches on the terraced land to improve the soil. The width of the terrace is not less than 2.5 meters, and the height of the ladder wall is not more than 1.2 meters; the width of the trench is 1 to 1.5 meters, and the depth is 0.8 to 1 meter. When backfilling the trench, soil improvement materials such as farmyard manure 3 shall be pressed and buried in layers. If there is no soil improvement material, all the plowing layer soil shall be backfilled.

2) Digging holes to improve soil:

According to the north-south direction and the east-west direction on the slope of the hilly land, according to the row spacing of citrus trees of 4.5 meters, the planting grid is used to determine the position of the soil improvement hole on the slope of the hilly area. The diameter of the soil hole is 1.5 meters. 0.8-1 meter deep circular nest. When backfilling the soil improvement hole, the soil improvement materials are pressed and buried in layers, and if there is no soil improvement material, all the plowing layer soil is backfilled.

The soil improvement method to the dry land in the citrus orchard garden is:

Retain the existing terraces or terraces, and adjust a small number of extremely irregular plots and special locations that affect citrus planting.

1) Trench reformation:

When moats are used to improve soil on dry land, for blocky dry land on gentle slopes with a slope of no more than 10%, the moats should run in a north-south direction, and the distance between citrus trees should be 4.5 meters to determine the distance between the moats.

For block dry land on a slope with a slope exceeding 10%, if the height difference between two adjacent plots is not greater than 70 cm, ditches shall be excavated along the entire slope in the direction of parallel contour lines, and the same ditches shall be set at on different plots. If the height difference between two adjacent plots is greater than 70 centimeters, several trenches are excavated on each plot with a row spacing of 4.5 meters, and the width of each plot is greater than 2.5 meters.

2) Digging holes to improve soil:

When digging holes to improve the soil, the dry land follows the north-south direction and the east-west plant direction, and according to the citrus tree row spacing of 4.5 meters, the location of the soil improvement holes is determined on the plot according to the planting grid.

The method for improving the soil of the paddy field in the described citrus orchard is:

1) Trench reformation:

When moats are used to improve soil in paddy fields, for paddy fields on flat land and gentle slopes with a slope of no more than 10%, the moats are directed north-south, and the distance between the moats is determined according to the row spacing of 4.5 meters, that is, the distance between the moats is 4.5 meters. The trench is connected with the drainage ditch, and the bottom of the ditch is set with a gradient of 0.3% to facilitate the timely discharge of accumulated water at the bottom of the ditch.

For terraced paddy fields on slopes with a slope of more than 10%, if the height difference between two adjacent paddy fields is not greater than 70 cm, the trenches shall be excavated in the direction of parallel contour lines on the entire slope, and the same trench Set up on different paddy fields. If the height difference between two adjacent paddy fields is greater than 70 centimeters, several ditches are excavated on each paddy field with a row spacing of 4.5 meters, and the width of the plot is greater than 2.5 meters.

2) Ditching and furrowing:

For paddy fields with a depth of active soil layer greater than 50 cm, ditching and furrowing are carried out, and citrus is planted on the furrow surface. For paddy fields with poor drainage performance, the width of the border I42 is set to 5 meters, and a row of citrus trees 5 is planted. For paddy fields with good drainage performance, the width of the border II 44 is set to 18 meters, and 4 rows of citrus trees 5 are planted. The depth of furrow 46 in flat land and low-lying paddy field is greater than 1 meter, and the depth of furrow 46 in paddy field is less than 1 meter.

3) Digging holes to improve soil:

When digging holes to improve the soil in paddy fields, for paddy fields with a depth of active soil layer greater than 80 cm and good water permeability under the plow layer, follow the north-south direction, east-west direction, and according to the row spacing of 4.5 meters, according to the planting grid. The location of digging holes is determined on the paddy field.

Specifically, in this embodiment, dig a trench with a width of 1 to 1.5 meters and a depth of 0.8 to 1 meter, and dig a circular soil improvement hole with a diameter of 1.5 meters and a depth of 0.8 to 1 meter. 1. Raw soil 2. Stones are stacked separately. The soil improvement materials in the present embodiment include fine soil improvement materials 32 and rough soil improvement materials 30, and the fine soil improvement materials 32 include farm manure and weeds, straw and branches through crushing or biogas fermentation, and farm manure and A mixture of one or more materials in crushed or biogas-fermented weeds, straw, and branches, and the rough improvement soil material 30 is weeds, straw, and branches that have not been crushed or biogas-fermented.

In this embodiment, both the backfilling of the ditch and the backfilling of soil improvement holes adopt the mixed filling method of soil and soil improvement materials: the soil improvement materials with a dry weight of 30 to 60 kg per cubic meter are filled in the trench in 3 to 5 layers, roughly The soil improvement material 30 is placed in the bottom layer, and the soil improvement material 32 is placed in the middle and upper layers, and each layer is filled with soil at a depth of 0.15 to 0.20 meters. When backfilling, mix the soil at a depth of 0.6 to 0.8 meters with rough soil improvement materials to a depth of 0.6 to 0.8 meters, and backfill the soil at a depth of 0.2 to 0.4 meters to a depth of 0.4 to 0.6 meters; The soil at a depth of one meter is mixed with the modified soil material to a depth of 0.6 to 0.8 meters, the original soil at a depth of 0.2 to 0.4 meters is backfilled to a depth of 0.4 to 0.6 meters, and the original topsoil 1 at a depth of 0 to 0.2 meters is backfilled and Reach a depth of 0.2 to 0.4 meters until the trench is filled and 0.3 to 0.4 meters above the original ground, so that the filling depth of topsoil 1 and soil improvement materials is in the distribution area of the citrus root system, so that the soil improvement materials are evenly distributed in the middle In the upper soil, make the soil more fertile and loose, and fully provide the required nutrients for the citrus trees.

If the soil pH value of the citrus garden is higher than 7, according to the strength of alkalinity, add 3-10 kg of sulfur powder per cubic meter of backfill soil to reduce the soil pH value. For soil with a pH value lower than 5, add 1 to 3 kg of lime to each cubic meter of backfill soil to increase the soil pH value. So that the soil in the citrus orchard reaches the best pH value suitable for the growth of citrus trees.

Apparently, the soil improvement method for citrus orchards provided by the present invention makes the soil pH of the citrus orchards in the mountain gorge reservoir area more suitable for the growth of citrus trees, and thickens the active soil layer by aiming at different topographical characteristics in the citrus orchards. The depth of the soil is more fertile and loose, which improves the water and fertilizer retention capacity of the soil in the garden. The balance of water and fertilizer meets and guarantees the water and fertilizer demand of citrus trees. The fruit setting rate of citrus is high, the fruit flavor is good, and the yield and quality are greatly improved. Improve and promote local economic benefits.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. For those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention , should be included within the protection scope of the present invention.

Claims (7)

1. a method for improving soil in a citrus orchard field, is characterized in that, comprises the following steps: S1: Select a 1,000-square-meter land preparation including hilly land, dry land and paddy fields with an altitude of less than 500 meters, relatively neat terrain, and a slope of hilly land not greater than 25° as an citrus orchard for planting citrus, within a linear range of ¹⁰ kilometers around the citrus orchard. No citrus quarantine pests and diseases; S2: Carry out ditches and dig holes to improve the soil on the hilly land and dry land, and carry out ditches to improve the soil, open ditches and make furrows, and dig holes to improve the soil on the paddy fields; The method for improving the soil in the hills and mountains in the citrus orchard is: 1) Trench reformation: For gentle slopes in hilly and mountainous areas with slopes less than 10%, excavate ditches in the north-south direction on the slopes of the hilly and mountainous areas to improve the soil; Meters of soil width as a retaining wall for intercepting rainwater and sediment; For the hilly and mountainous slopes with a slope greater than 10%, based on the construction of most of the terraces, the width of the terraces is an integral multiple of the planting row spacing, and the terraces are excavated along the contour line at a gradient of 0.3% to 0.5% according to the principle of contour. Digging ditches on the terraced land to improve the soil, the width of the terrace surface is greater than 2.5 meters, and the height of the ladder wall is less than 1.2 meters; the width of the trench is 1 to 1.5 meters, and the depth is 0.8 to 1 meter; If there is no soil improvement material, all backfill the plow layer soil; 2) Digging holes to improve soil: According to the north-south direction and the east-west direction on the slope of the hills and mountains, according to the size of the citrus tree row spacing, the field planting grid is adopted to determine the position of the soil improvement hole on the slope of the hills and mountains; when the soil improvement hole is backfilled Bury soil improvement materials layer by layer, if there is no soil improvement material, all backfill the plow layer soil; The soil improvement method to the dry land in the citrus orchard garden is: Retain the existing terraces or terraces, adjust a small number of extremely irregular plots and special locations that affect citrus planting; 1) Trench reformation: For blocky dry land on gentle slopes with a slope not exceeding 10%, the trenches are north-south, and the trench spacing is determined according to the row spacing of citrus trees; For block dry land on a slope with a slope exceeding 10%, if the height difference between two adjacent plots is not greater than 70 cm, the trenches shall be excavated on the entire slope in the direction of parallel contour lines, and the same trench shall be Installed on different plots; if the height difference between two adjacent plots is greater than 70 centimeters, several trenches are dug on each plot according to row spacing, and the width of the plots is greater than 2.5 meters; 2) Digging holes to improve soil: Described dry land is according to north-south direction, east-west plant direction, according to the size of citrus tree row spacing, determines the location of soil hole on the plot according to the field planting grid; The method for improving the soil of the paddy field in the described citrus orchard is: 1) Trench reformation: For flat land and paddy fields on gentle slopes where the slope is no more than 10%, the ditch adopts a north-south direction, and the distance between the ditch is determined according to the row spacing of citrus trees; For terraced paddy fields on slopes with a slope of more than 10%, if the height difference between two adjacent paddy fields is not greater than 70 cm, the trenches shall be excavated in the direction of parallel contour lines on the entire slope, and the same trench Installed on different paddy fields; if the height difference between two adjacent paddy fields is greater than 70 centimeters, excavate several trenches according to row spacing on each paddy field, and the width of the plot is greater than 2.5 meters; 2) Ditching and furrowing: For paddy fields with a depth of active soil layer greater than 50 cm, ditching and furrowing are carried out, and citrus is planted on the furrow surface; Citrus trees; for the paddy fields with good drainage performance, the width of the border surface is set to 10 meters to 20 meters, and 2 to 4 rows of citrus trees are planted; The depth is less than 1 meter; 3) Digging holes to improve soil: For paddy fields with a depth of active soil layer greater than 80 cm and good soil water permeability under the plow bed, according to the north-south direction, east-west plant direction, and according to the row spacing of citrus trees, determine the digging position on the paddy field according to the planting grid. 2. The soil improvement method for citrus orchards according to claim 1, wherein the trench is 1 to 1.5 meters wide and 0.8 to 1 meter deep, and the soil improvement hole is 1.5 meters in diameter and 0.8 to 1 meter deep. A circular nest of 1 meter, or a square nest with a length of 1.3 to 1.5 meters and a depth of 0.8 to 1 meter; the topsoil, raw soil, and stones dug out during the excavation of the trenches and soil improvement holes are stacked separately. 3. the soil improvement method of citrus orchard garden according to claim 1, is characterized in that, described soil improvement material comprises fine improvement soil material and rough improvement soil material, and described fine improvement soil material comprises farmyard manure and after crushing treatment or biogas-fermented weeds, stalks and branches, or a mixture of one or more materials in the farm manure and crushed or biogas-fermented weeds, stalks and branches; The materials are weeds, straw, and branches that have not been crushed or biogas-fermented. 4. The soil improvement method of the citrus orchard according to claim 1, characterized in that, the backfilling of the ditch and the soil improvement holes all adopt the mixed filling mode of soil and soil improvement materials: the dry weight per cubic meter is 30～ 60 kg of soil improvement materials are filled into the trench in 3 to 5 layers, the coarse soil improvement materials are placed on the bottom layer, the fine soil improvement materials are placed on the middle and upper layers, and each layer is filled with soil at a depth of 0.15 to 0.20 meters; when backfilling , mix the 0.6-0.8 m deep soil with the rough soil improvement material to reach a depth of 0.6-0.8 m, backfill the original 0.2-0.4 m deep soil to reach a 0.4-0.6 m depth; mix 0.6-0.8 The soil at a depth of one meter is mixed with the modified soil material to reach a depth of 0.6 to 0.8 meters, the original soil at a depth of 0.2 to 0.4 meters is backfilled to a depth of 0.4 to 0.6 meters, and the original surface soil at a depth of 0 to 0.2 meters is backfilled And reach a depth of 0.2 to 0.4 meters, until the trench is filled and 0.3 to 0.4 meters above the original ground, so that the filling depth of the topsoil and the soil improvement materials is in the distribution area of the citrus root system. 5. The soil improvement method of the citrus orchard according to claim 1, wherein if the soil pH value of the citrus orchard is higher than 7, according to the strength of alkalinity, add 3-10 kg of sulfur powder to reduce the soil pH value; for soil with a pH value lower than 5, add 1-3 kg of lime to each cubic meter of backfill soil to increase the soil pH value. 6 . The soil improvement method for citrus orchards according to claim 1 , characterized in that the row spacing of the citrus trees is 4 to 5.5 meters. 7. The soil improvement method of the citrus orchard according to claim 1, characterized in that, the underground water level of the citrus orchard is below 1 meter, and the soil-forming parent material is difficult to be weathered, and the height of the living soil layer is greater than 60 centimeters; If the parent material is easy to weather, the height of the active soil layer is greater than 20 cm, and the available water source is not less than 75 tons/mu during the autumn drought period.