CN106386412A - A method for automatic control of wide-row-spacing and split-root alternate irrigation - Google Patents

Abstract

The invention discloses an automatic control method for wide row-spacing and split-root alternate irrigation. A group of water delivery capillaries with solenoid valves are respectively arranged on both sides of the crop row, and any group of water delivery capillaries does not deliver water to the other group when delivering water. The soil moisture under the capillary is affected, and then two soil moisture sensors located on both sides of the crop row are prepared for each group of solenoid valves. Through the control of the central intelligent controller, the two groups of water delivery capillaries are respectively irrigated to both sides of the crop row in turn. . In the present invention, the horizontal wetting radii of the capillaries on both sides of the crop row have no influence on each other. According to the relationship between the soil moisture on both sides of the crop row and its interaction with the four soil moisture sensors and two sets of electromagnetic valves, the corresponding automatic control system The construction realizes high-efficiency and highly automated wide-row-spacing alternate root irrigation.

Description

A method for automatic control of wide-row-spacing and split-root alternate irrigation

technical field

The invention relates to the technical field of water-saving irrigation, in particular to a wide row-spacing split-root alternate irrigation technology.

Background technique

With the increasing shortage of fresh water resources and increasing water demand, the development of water-saving agriculture has become an important countermeasure for countries all over the world to achieve sustainable development under the constraints of water resources. my country's per capita water resources are only 2,300 cubic meters, about 1/4 of the world's average level, ranking 121st in the world, and one of the 13 water-poor countries in the world. At the same time, agriculture is a large water user, and agricultural irrigation water It accounts for about 65% of the total water supply in the country. However, the contradictions between insufficient water resources, severe waste and low utilization efficiency in agricultural production are very prominent, and it is more urgent to develop water-saving agriculture. In view of the current constraints of my country's farmland water conservancy investment level, improving surface irrigation will be the mainstream of water-saving irrigation for a long time, but in terms of water-saving potential, biological water-saving is the focus and hotspot of water-saving agriculture in the future. Therefore, The comprehensive water-saving technology integrating ground improvement and biological water-saving is the key research direction of water-saving agriculture in my country.

As early as the 1960s and 1970s, foreign scholars began to try to use interlaced irrigation and furrow irrigation technologies on some crops, and conducted systematic research on crop water use efficiency and evapotranspiration characteristics under these technologies. In 1996, on the basis of indoor potting, plot experiments, and field application experiments, Kang Shaozhong and others systematically proposed the alternate irrigation technology for crop root partitions for the first time, and clarified its concept, theoretical basis, and implementation methods. In 1997, Kang Shaozhong and others proposed four application modes suitable for alternate irrigation of fruit tree root zones, namely alternate trench irrigation system, mobile alternate drip irrigation system, ring automatic control alternate drip irrigation system and alternate seepage irrigation system. Combined with the reality of orchard irrigation in my country, some scholars have also proposed the development of alternate point irrigation technology. In addition, for sparsely planted field crops, the alternate water supply of different root zones can also be realized under the premise of integrated application of ridge and furrow irrigation technology.

As a new idea and new technology for farmland water-saving, controlled split-root alternate irrigation is still in its initial stage. Although it has been proved to be theoretically and practically possible and has great water-saving potential, it is still in the concrete stage. There are still some problems in the implementation process. For example, the cost of facilities and equipment such as water transmission and distribution pipelines may exceed that of conventional irrigation, thereby reducing its economic benefits; the quantification and operability of comprehensive alternate irrigation considering the movement process of soil water and the distribution of roots, etc. The level is still low; the automation level of the split-root alternate irrigation control system is still low, the cost is relatively high, and the structure is relatively complicated, which is not conducive to large-scale application and promotion.

Contents of the invention

The technical problem to be solved in the present invention is to provide an automatic control method for wide-row-spacing and split-root alternate irrigation, so that the horizontal wetting radii of the capillaries on both sides of the crop row have no influence on each other. The interaction relationship between the soil moisture sensor and two sets of solenoid valves realizes high-efficiency and highly automated wide-row-spacing alternate root irrigation through the construction of the corresponding automatic control system.

In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

An automatic control method for wide-row-spacing and split-root alternate irrigation. A group of water delivery capillaries with solenoid valves are respectively arranged on both sides of the crop row. Humidity is affected, and then two soil moisture sensors located on both sides of the crop row are prepared for each group of solenoid valves, and then based on the following three sets of conditions: ① The soil moisture content of any two points in the farmland soil at the same time cannot be exactly the same , ②Any group of capillary water delivery will not affect the soil moisture under the other group of capillary capillaries, ③The relationship between the soil moisture on both sides of the crop row and its relationship with the four soil moisture sensors and the two sets of solenoid valves Interaction relationship, through the control of the central intelligent controller, the two sets of water delivery capillaries are respectively irrigated to both sides of the crop row in turn, that is, the water delivery capillaries on the A side are automatically closed when the water delivery capillaries on the A side are irrigated, and the water delivery capillaries on the B side are closed when a certain soil humidity requirement is reached. The water delivery capillaries on both sides are closed. When the next irrigation is performed, the B side water delivery capillary is irrigated and the A side water delivery capillary is closed. After reaching a certain soil humidity requirement, both sides of the water delivery capillary are closed and the cycle is automatic.

As a kind of preferred technical scheme of the present invention:

Ⅰ. Set up a group of capillaries with solenoid valves on both sides of the crop row respectively. The two groups of solenoid valves and capillaries are marked as A and B respectively. When any group of capillaries is delivering water, it will not feed water to the other group. The soil moisture under the water capillary has an influence; and two soil moisture sensors are respectively buried under each group of water capillary, and a total of four soil moisture sensors are marked as 1, 2, 3, and 4 respectively;

Ⅱ. Set up a group of central intelligent controllers, on which there are power output channels, the four voltage signal input channels are marked as 1, 2, 3, 4, and the four relay alarm output channels are marked as 1, 2, 3, 4;

Ⅲ. Then set the soil moisture sensors 1 and 3 under the water delivery capillary A, correspondingly set the soil moisture sensors 2 and 4 under the water delivery capillary B; at the same time, set the four soil moisture sensors 1, 2 and 3 , 4 are respectively connected to the four-way voltage signal input channels 1, 2, 3, and 4 of the central intelligent controller, and the central intelligent controller receives the four-way voltage signals sent back by the four soil moisture sensors according to the soil moisture status, and then The 4-way voltage signal is compared with the preset 4-way alarm voltage value related to the soil field water holding capacity, and the central intelligent controller controls the opening and closing of the four-way relay alarm output channels according to the comparison results; and then the most important , connect 1 and 2 of the four-way relay alarm output channels with solenoid valve A in series, and connect 3 and 4 of the relay alarm output channels with solenoid valve B in series;

Ⅳ. Finally, set the alarm values corresponding to the four soil moisture sensors to be two high and two low, and the alarm values corresponding to the two soil moisture sensors below the same group of water capillaries are one high and one low;

Through the above settings, the two sets of capillary capillaries can respectively irrigate to both sides of the crop row in turn, that is, the capillary capillaries on side B will be closed when the capillary capillaries on side A are irrigating, and the capillary capillaries on both sides will be closed when a certain soil humidity requirement is reached. In the next irrigation, the water delivery capillary on the B side is irrigated and the water delivery capillary on the A side is closed. After reaching a certain soil humidity requirement, both sides of the water delivery capillary are closed and the cycle is automatic.

As a preferred technical solution of the present invention, in step III, the central intelligent controller is powered by a DC24v power supply, and the power output channels on it are connected to the four soil moisture sensors and provide the latter with a DC12v power supply.

As a preferred technical solution of the present invention, in step IV, the lower limit values of soil water content alarms corresponding to the four soil moisture sensors 1, 2, 3, and 4 are set to be 60%, 80%, and 80% of the field water capacity in turn. %, 60%; when the actual output value of the soil moisture sensor is lower than the preset value, the central intelligent controller controls the corresponding relay alarm output channel to close, and when all relay alarm output channels connected to a solenoid valve are closed , the solenoid valve is turned on for irrigation; otherwise, the solenoid valve is always closed.

As a preferred technical solution of the present invention, the water delivery capillary is arranged on a pressurized water delivery pipeline, and the pressurized water delivery pipeline includes a main pipe and several branch pipes, and valves are respectively arranged on the main pipe and the branch pipes.

As a preferred technical solution of the present invention, the two sets of capillary water delivery pipes on both sides of the crop row are installed on the same branch pipe through a bypass, and electromagnetic valves are respectively installed at the head of the capillary water delivery pipes.

As a preferred technical solution of the present invention, two sets of capillary water delivery pipes on both sides of the crop row are respectively installed on two parallel branch pipes, and electromagnetic valves are installed at the head of the branch pipes.

As a preferred technical solution of the present invention, the branch pipe adopts a Ф50mm PE pipe, the water delivery capillary adopts a Ф20mm PE drip irrigation belt, the distance between the drippers is 30cm, the horizontal wetting radius is 30cm, and the two groups on both sides of the crop row The distance between the water delivery capillaries is 100cm to ensure that the irrigation of one side of the water delivery capillaries will not increase the soil moisture content on the other side.

As a preferred technical solution of the present invention, the soil moisture sensor is a voltage-type sensor, which is buried deep in the root layer of the crop, works under the condition of a DC12v power supply, and outputs a 0-5v DC voltage according to the soil moisture content Signal, the relationship between soil water content Q and voltage signal V is: Q=V/5.

As a preferred technical solution of the present invention, the solenoid valve is a normally closed solenoid valve, the power supply is DC12v, it is opened when it is powered on, and it is closed when it is powered off.

The beneficial effects produced by adopting the above-mentioned technical scheme are:

The invention makes the horizontal wetting radius of the capillaries on both sides of the crop row have no mutual influence, and according to the relationship between the soil moisture on both sides of the crop row and its interaction with four soil moisture sensors and two sets of electromagnetic valves, the corresponding automatic control system The construction realizes high-efficiency and highly automated alternate root irrigation.

Specifically, the present invention uses simple and ingenious principle setting and system construction to "①at the same time, the soil moisture content of any two points in the farmland soil cannot be completely the same; The influence of the soil moisture under a group of water delivery capillaries; ③ the relationship between the soil moisture on both sides of the crop row and its interaction with the four soil moisture sensors and the two sets of solenoid valves”—based on these three points, with the help of very Simple sets of sensors, solenoid valves and simple controllers efficiently and highly automatically realize two groups of water delivery capillaries to irrigate to both sides of the crop row in turn, that is, side B water delivery capillaries are closed when A side water delivery capillaries are irrigating When a certain soil moisture requirement is reached, both sides of the water delivery capillary are closed. When the next irrigation is performed, the water delivery capillary on the B side is irrigated and the water delivery capillary on the A side is closed.

The system of the present invention has three core points: ① the soil moisture sensors 1 and 3 are set under the water delivery capillary A, and the soil moisture sensors 2 and 4 are correspondingly set under the water delivery capillary B; ② four soil moisture sensors 1, 3 2, 3, and 4 are respectively connected to the four-way voltage signal input channels 1, 2, 3, and 4 of the central intelligent controller, and 1, 2 of the four-way relay alarm output channels are connected to the solenoid valve A, 3, 4. Connect to the solenoid valve B; ③The alarm values corresponding to the four soil moisture sensors are two high and two low, and the alarm values corresponding to the two soil moisture sensors below the same group of water capillaries are one high and one low—see Example 3 below , it is the interaction of the above-mentioned three points setting that has reached the technical effect of automatic split-root irrigation of the present invention.

In addition, the method of the present invention also integrates the split-root water-saving irrigation technology to keep the soil in the active layer of the crop root system dry in a certain area of the horizontal (vertical) profile, and at the same time make the roots appear alternately in the dry areas of the horizontal (vertical) profile, Always keep a part of the crop root system growing in a dry or drier soil environment, such a control effect has a very high water saving and yield increase effect; this is because, first of all, the crop root system in the dry area will generate water stress signals to the Leaf stomata, so as to effectively regulate the closure of leaf stomata and control transpiration, while the roots of crops in humid areas absorb water from the soil to meet the minimum life needs of crops and keep the damage to crops within critical limits; secondly, split roots During alternate irrigation, the soil surface is always intermittently in the dry area, which can not only reduce the ineffective evaporation loss between trees, but also improve the air permeability of the soil, promote the compensatory growth of crop roots, enhance the function of the root system, and improve the root system’s ability to soil moisture, Nutrient utilization.

Description of drawings

Fig. 1 is a schematic diagram of a specific embodiment of the present invention, wherein two groups of capillary tubes A and B are installed on the same branch pipe, and a solenoid valve is installed at the head of the capillary tube.

Fig. 2 is a schematic diagram of another specific embodiment of the present invention, wherein two groups of capillary tubes A and B are respectively installed on two parallel branch pipes, and electromagnetic valves are installed at the head of the branch pipes.

In the figure: central intelligent controller (1), branch pipe (2), capillary water delivery pipe (3), solenoid valve (4), soil moisture sensor (5).

detailed description

The following are the embodiments given by the inventor. It should be noted that these embodiments are all preferred examples of the present invention. Equivalent replacement and addition of technical features all belong to the protection scope of the present invention.

Embodiment 1, pipeline installation system

The branch pipe adopts Ф50mm PE pipe, the capillary pipe adopts Ф20mm PE drip irrigation belt, the distance between drippers is 30cm, and the horizontal wetting radius is 30cm. The capillary pipe is connected to the branch pipe through a bypass. A capillary tube is arranged on the left and right sides of each row of crops, and the distance between the two capillary tubes is 100cm, which can ensure that the soil moisture (water content) at the capillary tube on the other side will not increase when the capillary tube on one side is irrigated. Two groups A and B, Figure 1 shows the schematic diagram of the capillary pipes of A and B groups installed on the same branch pipe, and a solenoid valve is installed at the head of each capillary pipe, the solenoid valve is a normally closed solenoid valve, and the power supply is DC12v, that is, power on, power off and off. Figure 2 shows that the capillary tubes of A and B groups are respectively installed on two parallel branch pipes, and solenoid valves are installed at the head of the branch pipes.

Embodiment 2, automatic control system

Select a row of crops, and install soil moisture sensors on the left and right sides of the crop row, that is, near the two capillary tubes. There are 4 soil moisture sensors, which are divided into two groups on average, namely, sensors-1, 3 and sensors-2, 4 , which are respectively located at the capillaries on the left and right sides of the crop planting row, buried deep near the root layer of the crop. The soil moisture sensor is a voltage sensor, that is, under the condition of DC12v power supply, it will output a 0-5v DC voltage signal according to the size of the soil moisture (water content). The relationship between soil water content (Q) and voltage signal (v) is: Q=V/5. Its power supply is provided by the power output channel of the central intelligent controller, and the 0-5v DC voltage signal is sent to the central intelligent controller through the voltage input channel, and compared with the lower limit value of the soil humidity (water content) alarm, set 4 here The soil moisture (water content) alarm lower limit of the soil moisture sensor is 60%, 80%, 80%, and 60% of the field water capacity in turn.

Embodiment 3, automatic realization of wide-row-spacing split-root alternate irrigation

First of all, it is clear that the goal of this research is: "Under the condition of wide row spacing, efficiently and highly automatically realize two groups of capillary water delivery to irrigate both sides of the crop row in sequence, that is, water delivery from side A to side B while capillary irrigation from side A The capillary is closed. When a certain soil humidity requirement is reached, both sides of the water delivery capillary are closed. When the next irrigation is performed, the B side water delivery capillary is irrigated while the A side water delivery capillary is closed. After a certain soil humidity requirement is reached, both sides of the water delivery capillary are closed. cycle".

Before split-root alternate irrigation, there may be some differences in soil moisture (water content) at different points in the farmland soil, but not too much. At the same time, among the four soil moisture sensors, the soil moisture of the second and third ( water content) alarm lower limit value is 80% of the field water holding capacity, so in the process of farmland evapotranspiration, the second and third soil moisture sensors alarm first, thus driving the corresponding second and third alarm output channels to close . In addition, the soil moisture (water content) at any two points in the farmland soil cannot be exactly the same, and there will be more or less differences. The value of the soil moisture sensor-1 first drops to the lower limit of the alarm of the central intelligent controller (60% of the field water holding capacity), thereby driving the corresponding first alarm output channel to close first, and then the corresponding solenoid valve A is opened. In group A (right side), the capillary starts to irrigate until the field capacity is reached and stops. Since the third soil moisture sensor is located at the capillary on the right side of the crop row (group A), the measured soil moisture value will change from small to large until the field water capacity, which will cause the closed third alarm output channel to be disconnected, even if the soil moisture (water content) measured by the fourth soil moisture sensor drops to 60% of the field water holding capacity, the corresponding fourth alarm output channel is closed, and the solenoid valve B will not open, and group B ( Left) The capillary will not irrigate either.

With the end of the capillary irrigation process on the right side of the crop row (Group A), the water content of the soil on the right side of the crop row is above and below the field water capacity; since the capillary spacing on both sides of the crop row is wide enough, there is no interaction between the capillary water on both sides of the crop row. Influence, that is, the irrigation of the capillary on the right will not increase the soil moisture (water content) on the left, so the soil moisture (water content) on the left side of the crop row is basically below 60% of the field water capacity. At this time, the corresponding The 2nd and 4th alarm output channels are in the closed state. In the subsequent process of farmland evapotranspiration, because the soil moisture (water content) lower limit alarm values of the 1st and 3rd soil moisture sensors are respectively 60% and 80% of the field water holding capacity. %, so the corresponding No. 3 alarm output channel will be closed first, and then the corresponding solenoid valve B will be opened, and the capillary tubes of group B (left side) will start to irrigate until the water holding capacity of the field is reached and the irrigation will stop. Since the second soil moisture sensor is located at the capillary on the left side of the crop row (group B), the measured soil moisture value will change from small to large until the field water capacity, which will cause the closed second alarm output channel to be Disconnected, even if the soil moisture (water content) measured by the first soil moisture sensor drops to 60% of the field water holding capacity, the corresponding first alarm output channel is closed, and the solenoid valve A will not be opened. Group A ( Right) The capillary will not irrigate either.

With the end of the capillary irrigation process on the left side of the crop row (Group B), the water content of the soil on the left side of the crop row is above and below the field water capacity; since the capillary spacing on both sides of the crop row is wide enough, there is no interaction between the capillary water on both sides of the crop row. Influence, that is, the irrigation of the capillary on the left will not increase the soil moisture (water content) on the right, so the soil moisture (water content) on the right side of the crop row is basically between 60% and 80% of the field water capacity. When the corresponding third alarm output channel is in the closed state, in the subsequent farmland evapotranspiration process, since the soil moisture (water content) lower limit alarm values of the second and fourth soil moisture sensors are respectively 80% of the field water holding capacity and 60%, so the corresponding second alarm output channel will be closed first, and now the remaining 1st and 4th alarm output channels are still in the disconnected state, which one will be closed first depends on the first and fourth soil moisture sensors. The soil moisture (water content) obtained first reaches 60% of the field water holding capacity. Since the capillary on the left side of the crop row (Group B) has just been irrigated with water, the first soil located at the capillary on the right side of the crop row (Group A) The soil humidity (water content) measured by the moisture sensor will first reach 60% of the field water holding capacity, the corresponding first alarm output channel will be closed first, and then the corresponding solenoid valve A will be opened, and the capillary tube of group A (right side) will be closed. Start to irrigate until the field capacity is reached and stop.

Circulation in turn can realize the automatic control process of root-by-root alternate irrigation under the condition of wide row spacing. That is, when the soil moisture (water content) on the right side of the crop row reaches 60% of the field water holding capacity, and at the same time the soil moisture (water content) on the left side reaches 80% of the field water holding capacity, the capillary on the right side starts to irrigate water; similarly, when the crop row left When the soil moisture (water content) on the side reaches 60% of the field water holding capacity, and at the same time the soil moisture (water content) on the right side reaches 80% of the field water holding capacity, the capillary on the left side starts to irrigate.

Visible, the achievement of the research goal of the present invention is based on the following three points: "1. the soil water content of any two points of the farmland soil at the same moment can not be completely the same; The influence of the soil moisture under the capillary; ③ the relationship between the soil moisture on both sides of the crop row and its interaction with the four soil moisture sensors and the two sets of solenoid valves".

According to the size of soil humidity (water content) at 4 points on both sides of the crop row and the combined action relationship, the present invention drives two groups of electromagnetic valves on both sides of the crop row to automatically open and close alternately, and through the water transmission and distribution pipes and capillary pipes, the irrigation water is timely , An appropriate amount is transported to the left and right sides of the crops to provide water protection for the normal growth of the crops. The automatic control system and method for split-root alternate irrigation can improve the automation level of water-saving irrigation, and has the characteristics of energy saving, environmental protection, greenness and low carbon.

The present invention faces the demands of agricultural modernization and water resources security, and focuses on the problems of extensive agricultural water use and low level of water-saving irrigation automation, and conducts research on the automatic control system and method of wide-row-spacing and split-root alternate irrigation, and integrates and innovates modern sensor technology and Intelligent control technology realizes the automatic control of wide-row spacing and alternate root irrigation, and provides a new efficient and practical technical means for water-saving irrigation automation.

The above description is only proposed as an implementable technical solution of the present invention, and not as a single restriction on the technical solution itself.

Claims (10)

1. A method for automatic control of wide row-spacing and split-root alternate irrigation, characterized in that: a group of water delivery capillaries (3) with electromagnetic valves (4) are respectively arranged on both sides of the crop row, and any group of water delivery capillaries (3) ) does not affect the soil moisture under the other set of capillary tubes (3), then prepare two soil moisture sensors (5) located on both sides of the crop row for each set of solenoid valves (4), and then the following Based on the above three sets of conditions: ① At the same time, the soil moisture content of any two points in the farmland soil cannot be exactly the same; ②When any group of water delivery capillaries delivers water, it will not affect the soil moisture under the other group of water delivery capillaries; ③The relationship between the soil moisture on both sides of the crop row and its interaction with the four soil moisture sensors and two sets of solenoid valves; Through the control of the central intelligent controller (1), the two sets of capillaries for water delivery (3) are respectively irrigated to both sides of the crop row in turn, that is, the water delivery capillary for side A (3) is automatically realized while the water delivery capillary for side B (3) is irrigated. Closed, when a certain soil moisture requirement is reached, both sides of the water delivery capillary (3) are closed, and when the next irrigation is performed, the water delivery capillary on the B side (3) is irrigated and the water delivery capillary on the A side (3) is closed. The side water delivery capillaries (3) are all closed and circulated automatically. 2. the wide-row-spacing root-dividing alternate irrigation automatic control method according to claim 1, is characterized in that: Ⅰ. Set up a group of capillaries (3) with solenoid valves (4) on both sides of the crop row. The two groups of solenoid valves (4) and capillaries (3) are marked as A and B respectively. The water delivery capillary (3) does not affect the soil moisture under the other set of water delivery capillaries (3) when delivering water; and two soil moisture sensors (5) are respectively buried under each group of water delivery capillaries (3), totaling four The soil moisture sensors (5) are marked as 1, 2, 3, 4 respectively; Ⅱ. Set up a group of central intelligent controllers (1), which are equipped with power output channels, four voltage signal input channels are marked as 1, 2, 3, 4, and four relay alarm output channels are marked as 1, 2, 3 , 4; Ⅲ. Then set the soil moisture sensors 1 and 3 under the water delivery capillary A, correspondingly set the soil moisture sensors 2 and 4 under the water delivery capillary B; at the same time, set the four soil moisture sensors 1, 2 and 3 , 4 are respectively connected to the four-way voltage signal input channels 1, 2, 3, and 4 of the central intelligent controller, and the central intelligent controller receives the four-way voltage signals sent back by the four soil moisture sensors according to the soil moisture status, and then The 4-way voltage signal is compared with the preset 4-way alarm voltage value related to the soil field water holding capacity, and the central intelligent controller controls the opening and closing of the four-way relay alarm output channels according to the comparison results; and then the most important , connect 1 and 2 of the four-way relay alarm output channels with solenoid valve A in series, and connect 3 and 4 of the relay alarm output channels with solenoid valve B in series; Ⅳ. Finally, set the alarm values corresponding to the four soil moisture sensors to be two high and two low, and the alarm values corresponding to the two soil moisture sensors below the same group of water capillaries are one high and one low; Through the above settings, the two sets of capillaries (3) can be used to irrigate both sides of the crop row in turn, that is, the water capillaries (3) on the side A can be automatically closed when the capillaries on the side B (3) are irrigating, and the soil humidity can reach a certain level. After the request, both sides of the water delivery capillary (3) are closed, and the next time the B side water delivery capillary (3) is irrigated while the A side water delivery capillary (3) is closed, after a certain soil humidity requirement is reached, the water delivery capillary on both sides (3 ) are closed, automatic cycle. 3. The method for automatic control of wide row-spacing alternate root irrigation according to claim 2, characterized in that: in step III, the central intelligent controller (1) is powered by a DC24v power supply, and the power output channel on it is connected to the The above four soil moisture sensors (5) are connected and provide DC12v power for the latter. 4. The automatic control method for wide-row-spacing and split-root alternate irrigation according to claim 2, characterized in that: in step IV, set the lower limit value of the soil moisture content alarm corresponding to four soil moisture sensors 1, 2, 3, and 4 60%, 80%, 80%, and 60% of the field water holding capacity in turn; when the actual output value of the soil moisture sensor is lower than the preset value, the central intelligent controller controls the corresponding relay alarm output channel to close. When all relay alarm output channels connected to a certain solenoid valve are closed, the solenoid valve is turned on for irrigation; otherwise, the solenoid valve is always closed. 5. The method for automatic control of wide row-spacing and split-root alternate irrigation according to claim 2, characterized in that: the water delivery capillary (3) is arranged on a pressurized water delivery pipeline, and the pressurized water delivery pipeline includes a main pipe and several branch pipes ( 2) There are valves on the main pipe and the branch pipe respectively. 6. The automatic control method for wide row-spacing and split-root alternate irrigation according to claim 5, characterized in that: two sets of capillary water delivery pipes (3) on both sides of the crop row are installed on the same branch pipe (2) by bypassing, and Electromagnetic valves (4) are respectively installed at the head of the water delivery capillary (3). 7. The automatic control method for wide-row-spacing and split-root alternate irrigation according to claim 5, characterized in that: two sets of capillary water delivery pipes (3) on both sides of the crop row are respectively installed on two parallel branch pipes (2), and Install the solenoid valve (4) at the head of the branch pipe. 8. The automatic control method for wide row-spacing alternate root irrigation according to claim 6 or 7, characterized in that: the branch pipe (2) adopts Ф50mm PE pipe, and the water delivery capillary (3) adopts Ф20mm PE drip irrigation The distance between the drippers is 30cm, the horizontal wetting radius is 30cm, and the distance between the two groups of water delivery capillaries (3) on both sides of the crop row is 100cm to ensure that the water delivery capillaries (3) on one side will not cause the soil on the other side to irritate. increase in water content. 9. The method for automatic control of wide row-spacing and split-root alternate irrigation according to claim 2, characterized in that: the soil moisture sensor (5) is a voltage-type sensor buried deep in the root layer of crops, and it is powered by a DC12v power supply Under the work, output a 0-5v DC voltage signal according to the soil water content, the relationship between the soil water content Q voltage signal V is: Q=V/5. 10. The method for automatic control of wide row-spacing alternate root irrigation according to claim 2, characterized in that: the solenoid valve (4) is a normally closed solenoid valve, and the power supply is DC12v.