A root zone soil water and nitrogen growth and decline type drip irrigation method and drip irrigation device

Abstract

The present application belongs to the field of agricultural production and environmental protection, and specifically relates to a root zone soil water and nitrogen growth and decline type drip irrigation method and a drip irrigation device. In the drip irrigation process, the water input amount of the left root zone soil of crops relative to the right root zone soil is reduced, and the nitrogen nutrient input amount of the left root zone soil of crops relative to the right root zone soil is increased, so that the water and nitrogen of the two sides of the root zone soil are input in a growth and decline type, the distribution of the water and nitrate nitrogen of the root zone soil on the two sides is regulated in a growth and decline type, and the leaching of soil nitrate nitrogen is reduced without negatively affecting the yield of crops.

Description

Technical Field

[0001] This invention belongs to the field of agricultural production and environmental protection, specifically a drip irrigation method and device for the dynamic balance of water and nitrogen in the root zone soil. Background Technology

[0002] my country's greenhouse vegetable cultivation area reaches 34 million mu (approximately 2.6 million hectares), accounting for about 80% of the total greenhouse crop cultivation area, and its output accounts for more than 25% of the country's total vegetable output. Greenhouse vegetable production in my country primarily uses soil as the cultivation substrate, and water and fertilizer measures (including input dosage, frequency, and methods) are often inadequate, leading to significant nutrient leaching. Nitrate nitrogen, in particular, dissolves in the soil solution in anionic form and is difficult for the soil to adsorb, resulting in especially severe leaching of nitrogen nutrients, primarily nitrate nitrogen.

[0003] Water and fertilizer management primarily affects soil moisture and nitrogen leaching by influencing the spatial and temporal distribution of water and easily mobile nitrogen components, mainly nitrate nitrogen, in the crop root zone. During the growth of greenhouse crops, timely selection of appropriate water and fertilizer management measures (including dosage, frequency, and method of application) is crucial to controlling soil moisture and nitrate nitrogen content and their distribution within suitable ranges in the crop root zone, meeting crop growth requirements while controlling nitrogen leaching. Reducing the nitrogen concentration in the leachate while keeping soil moisture leaching constant, or reducing water leaching while keeping nitrogen concentration in the leachate constant, or simultaneously reducing both soil moisture leaching and nitrogen concentration in the leachate, can all mitigate soil nitrogen leaching.

[0004] In my country, greenhouse vegetable production is mainly concentrated in the northern regions where groundwater with relatively high salinity is often used for irrigation. Water-saving irrigation technologies, primarily drip irrigation with integrated water and fertilizer management, are often combined with large-scale water leaching to control soil salinity. However, this approach does not effectively achieve water conservation or control nitrogen nutrient loss. Root zone irrigation, as a water-saving technique, is generally used for open-field crops in water-scarce areas, particularly fruit trees and wide-row furrow-irrigated crops. Its application in greenhouse vegetable production is very limited. This is because, on the one hand, it often requires large-scale water leaching to control soil salinity; on the other hand, it is difficult to achieve stable yields for greenhouse crops, especially for water-intensive greenhouse vegetables such as cucumbers. Conversely, constant-volume drip irrigation with integrated water and fertilizer management, which does not particularly emphasize water conservation, can better control soil salinity and fertilizer damage and stabilize crop yields, and is widely used in greenhouse vegetable production in my country.

[0005] However, under the integrated water and fertilizer drip irrigation system, the leaching of nitrogen nutrients, mainly nitrate nitrogen, is still quite serious, generally not less than 30%. It is essential to develop new water and fertilizer drip irrigation technologies to better control the leaching of nitrogen nutrients, primarily nitrate nitrogen, and to promote green production in facility agriculture. This need is even more urgent for facility vegetable production, such as facility cucumber production, which has high water consumption and severe nitrogen nutrient loss. Summary of the Invention

[0006] In view of the above-mentioned problems of existing integrated water and fertilizer drip irrigation, the purpose of this invention is to provide a drip irrigation method and drip irrigation device based on the fluctuation of water and nitrogen in the root zone soil.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] The root zone soil water and nitrogen fluctuation drip irrigation method of the present invention is as follows: during the drip irrigation process, the water input of the soil on the left side of the crop root zone relative to the soil on the right side of the crop root zone is reduced, and the nitrogen nutrient input of the soil on the left side of the crop root zone relative to the soil on the right side of the crop root zone is increased, so as to realize the fluctuation of water and nitrogen input in the root zones on both sides, thereby regulating the distribution of soil water and nitrate nitrogen in the root zone relative to both sides and reducing the leaching of soil nitrate nitrogen.

[0009] Wherein: the water input of the soil in the left root zone of the crop is 40% to 80% of the water input of the soil in the right root zone.

[0010] The nitrogen nutrient input in the soil of the left root zone of the crop is 1.2 to 3.0 times that in the soil of the right root zone.

[0011] The drip holes in the soil on the left and right sides of the crop root zone are 5 to 20 centimeters away from the crop roots.

[0012] The nitrogen nutrient input to the root zone soil includes the input of nitrogen from fertilizer and the input of nitrogen nutrients contained in the irrigation water itself.

[0013] This invention discloses a drip irrigation device for implementing a root zone soil water-nitrogen fluctuation drip irrigation method. The device includes an irrigation pump, a left root zone irrigation valve, a right root zone irrigation valve, a left root zone irrigation main pipe, a right root zone irrigation main pipe, a nitrogen fertilizer solution tank, a fertilizer suction pump, a left root zone fertilizer suction valve, a right root zone fertilizer suction valve, a left root zone drip irrigation tape, a right root zone drip irrigation tape, a left root zone fertilizer suction pipe, and a right root zone fertilizer suction pipe. One end of the left and right root zone irrigation main pipes is connected to the irrigation pump, or one end of the left and right root zone irrigation main pipes is connected to the irrigation pump via the left and right root zone irrigation valves, respectively. The other end of the left and right root zone irrigation main pipes is connected to the left and right root zone drip irrigation tapes, respectively. The left and right root zone drip irrigation tapes are respectively arranged on the root zone soil on the left and right sides of the crop roots. When the left root zone is irrigated... When one end of the main irrigation pipe and the right root zone irrigation main pipe are respectively connected to the irrigation pump, the left root zone irrigation main pipe and the right root zone irrigation main pipe are respectively equipped with a left root zone irrigation valve and a right root zone irrigation valve; the inlet of the fertilizer pump is connected to the nitrogen fertilizer solution tank, one end of the left root zone fertilizer suction pipe and the right root zone fertilizer suction pipe are respectively connected to the outlet of the fertilizer pump, or one end of the left root zone fertilizer suction pipe and the right root zone fertilizer suction pipe are respectively connected to the outlet of the fertilizer pump through the left root zone fertilizer suction valve and the right root zone fertilizer suction valve, and the other end of the left root zone fertilizer suction pipe and the right root zone fertilizer suction pipe are respectively connected to the left root zone irrigation main pipe and the right root zone irrigation main pipe; when one end of the left root zone fertilizer suction pipe and the right root zone fertilizer suction pipe are respectively connected to the outlet of the fertilizer pump, the left root zone fertilizer suction pipe and the right root zone fertilizer suction pipe are respectively equipped with a left root zone fertilizer suction valve and a right root zone fertilizer suction valve.

[0014] Wherein: the outlet of the irrigation pump is connected to one interface of the tee A, and the other two interfaces of the tee A are respectively connected to one end of the left root zone irrigation main pipe and the right root zone irrigation main pipe, or the other two interfaces of the tee A are respectively connected to one end of the left root zone irrigation valve and the right root zone irrigation valve, and the other ends of the left root zone irrigation valve and the right root zone irrigation valve are respectively connected to one end of the left root zone irrigation main pipe and the right root zone irrigation main pipe.

[0015] The outlet of the fertilizer pump is connected to one port of the tee B. The other two ports of the tee B are respectively connected to one end of the left root zone fertilizer suction pipe and the right root zone fertilizer suction pipe. Alternatively, the other two ports of the tee B are respectively connected to one end of the left root zone fertilizer suction valve and the right root zone fertilizer suction valve. The other ends of the left root zone fertilizer suction valve and the right root zone fertilizer suction valve are respectively connected to one end of the left root zone fertilizer suction pipe and the right root zone fertilizer suction pipe.

[0016] Under the same operating time, by reducing the opening degree of the left root zone irrigation valve relative to the right root zone irrigation valve and increasing the opening degree of the left root zone fertilizer absorption valve relative to the right root zone fertilizer absorption valve, the water input rate and nitrogen nutrient input rate of the left and right root zone drip irrigation tapes are adjusted in a variable manner to achieve variable input of soil water and nitrogen in the root zones on both sides of the crop; or, by reducing the opening time of the left root zone irrigation valve relative to the right root zone irrigation valve and increasing the opening time of the left root zone fertilizer absorption valve relative to the right root zone fertilizer absorption valve, the water input time and nitrogen nutrient input time of the left and right root zone drip irrigation tapes are adjusted in a variable manner to achieve variable input of soil water and nitrogen in the root zones on both sides of the crop.

[0017] The advantages and positive effects of this invention are as follows:

[0018] 1. Under the premise of the same water input and the same nitrogen input, compared with the constant drip irrigation of fertigation, the present invention can regulate the input of soil water and nitrogen in the root zone on both sides of the crop in a dynamic manner, and regulate the distribution of soil water and nitrate nitrogen in the root zone relative to both sides. In this way, the concentration of nitrate nitrogen in the soil leachate can be reduced without reducing water leaching, thereby reducing nitrogen leaching.

[0019] 2. Compared with root zone irrigation with reduced irrigation, this invention does not need to worry about the crop yield being affected by excessively dry soil in some root zones, nor does it need to worry too much about the problem of high mineralization of irrigation water aggravating soil salinity. The drip irrigation method of this invention is suitable for the production of crops with high water consumption and a certain degree of drought resistance (such as tomatoes), and is even more suitable for the production of crops with high water consumption and less drought resistance (such as cucumbers). Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the drip irrigation device of the present invention;

[0021] Wherein: 1 is the irrigation pump, 2 is the irrigation valve for the left root zone, 3 is the irrigation valve for the right root zone, 4 is the main irrigation pipe for the left root zone, 5 is the main irrigation pipe for the right root zone, 6 is the nitrogen fertilizer solution tank, 7 is the fertilizer suction pump, 8 is the fertilizer suction valve for the left root zone, 9 is the fertilizer suction valve for the right root zone, 10 is the drip irrigation tape for the left root zone, 11 is the drip irrigation tape for the right root zone, 12 is tee A, 13 is the fertilizer suction pipe for the left root zone, 14 is the fertilizer suction pipe for the right root zone, and 15 is tee B. Detailed Implementation

[0022] The invention will now be described in further detail with reference to the accompanying drawings.

[0023] The root zone soil water and nitrogen fluctuation drip irrigation method of the present invention is as follows: During the drip irrigation process, the water input of the soil on the left side of the crop root zone relative to the soil on the right side of the crop root zone is reduced, and the nitrogen nutrient input of the soil on the left side of the crop root zone relative to the soil on the right side of the crop root zone is increased, so as to realize the fluctuation of water and nitrogen input in the root zones on both sides, thereby regulating the distribution of soil water and nitrate nitrogen in the root zone relative to both sides and reducing the leaching of soil nitrate nitrogen.

[0024] In this embodiment, the nitrogen nutrient input to the root zone soil includes the input of nitrogen from fertilizer and the input of nitrogen nutrients contained in the irrigation water itself.

[0025] In this embodiment, the water input of the soil in the left root zone of the crop is 40% to 80% of that in the right root zone, and the nitrogen nutrient input of the soil in the left root zone is 1.2 to 3.0 times that in the right root zone. The drip irrigation sites of the soil in the left and right root zones are 5 to 20 cm away from the crop roots.

[0026] like Figure 1As shown, the root zone soil water-nitrogen fluctuation drip irrigation device of the present invention includes an irrigation pump 1, a left root zone irrigation valve 2, a right root zone irrigation valve 3, a left root zone irrigation main pipe 4, a right root zone irrigation main pipe 5, a nitrogen fertilizer solution tank 6, a fertilizer suction pump 7, a left root zone fertilizer suction valve 8, a right root zone fertilizer suction valve 9, a left root zone drip irrigation tape 10, a right root zone drip irrigation tape 11, a left root zone fertilizer suction pipe 13, and a right root zone fertilizer suction pipe 14. One end of the left root zone irrigation main pipe 4 and the right root zone irrigation main pipe 5 are respectively connected to the irrigation pump 1, or one end of the left root zone irrigation main pipe 4 and the right root zone irrigation main pipe 5 are connected to the irrigation pump 1. The ends of the main irrigation pipes 4 and 5 are connected to the irrigation pump 1 via the left root zone irrigation valve 2 and the right root zone irrigation valve 3, respectively. The other ends of the main irrigation pipes 4 and 5 are connected to the left root zone drip irrigation tape 10 and the right root zone drip irrigation tape 11, respectively. The left root zone drip irrigation tape 10 and the right root zone drip irrigation tape 11 are respectively arranged on the root zone soil on the left and right sides of the crop roots. When one end of the main irrigation pipe 4 and the right root zone irrigation pipe 5 is connected to the irrigation pump 1, the left root zone irrigation valve 2 and the right root zone irrigation valve 3 are respectively installed on the main irrigation pipe 4 and the right root zone irrigation pipe 5. The inlet of the fertilizer pump 7 is connected to the bottom of the nitrogen fertilizer solution tank 6. One end of the left root zone fertilizer suction pipe 13 and the right root zone fertilizer suction pipe 14 are respectively connected to the outlet of the fertilizer pump 7, or one end of the left root zone fertilizer suction pipe 13 and the right root zone fertilizer suction pipe 14 are respectively connected to the outlet of the fertilizer pump 7 through the left root zone fertilizer suction valve 8 and the right root zone fertilizer suction valve 9. The other end of the left root zone fertilizer suction pipe 13 and the right root zone fertilizer suction pipe 14 are respectively connected to the left root zone irrigation main pipe 4 and the right root zone irrigation main pipe 5. When one end of the left root zone fertilizer suction pipe 13 and the right root zone fertilizer suction pipe 14 are respectively connected to the outlet of the fertilizer pump 7, the left root zone fertilizer suction pipe 13 and the right root zone fertilizer suction pipe 14 are respectively equipped with the left root zone fertilizer suction valve 8 and the right root zone fertilizer suction valve 9.

[0027] The outlet of irrigation pump 1 is connected to one port of tee A12. The other two ports of tee A12 are connected to one end of the left root zone irrigation main pipe 4 and the right root zone irrigation main pipe 5, respectively. Alternatively, the other two ports of tee A12 are connected to one end of the left root zone irrigation valve 2 and the right root zone irrigation valve 3, respectively. The other ends of the left root zone irrigation valve 2 and the right root zone irrigation valve 3 are connected to one end of the left root zone irrigation main pipe 4 and the right root zone irrigation main pipe 5, respectively. In this embodiment, the outlet of irrigation pump 1 is connected to the first port of tee A12, the second port of tee A12 is connected to one end of the left root zone irrigation main pipe 4, and the left root zone irrigation main pipe 4 is equipped with the left root zone irrigation valve 2; the third port of tee A12 is connected to one end of the right root zone irrigation main pipe 5, and the right root zone irrigation main pipe 5 is equipped with the right root zone irrigation valve 3.

[0028] The outlet of the fertilizer pump 7 is connected to one port of the tee B15. The other two ports of the tee B15 are connected to one end of the left root zone fertilizer suction pipe 13 and the right root zone fertilizer suction pipe 14, respectively. Alternatively, the other two ports of the tee B15 are connected to one end of the left root zone fertilizer suction valve 8 and the right root zone fertilizer suction valve 9, respectively. The other ends of the left root zone fertilizer suction valve 8 and the right root zone fertilizer suction valve 9 are connected to one end of the left root zone fertilizer suction pipe 13 and the right root zone fertilizer suction pipe 14, respectively. In this embodiment, the outlet of the fertilizer pump 7 is connected to the first port of the tee B15, the second port of the tee B15 is connected to one end of the left root zone fertilizer suction pipe 13, the left root zone fertilizer suction pipe 13 is equipped with the left root zone fertilizer suction valve 8, and the third port of the tee B15 is connected to one end of the right root zone fertilizer suction pipe 14, the right root zone fertilizer suction pipe 14 is equipped with the right root zone fertilizer suction valve 9.

[0029] Under the same operating time, by reducing the opening degree of the left root zone irrigation valve 2 relative to the right root zone irrigation valve 3, and increasing the opening degree of the left root zone fertilizer absorption valve 8 relative to the right root zone fertilizer absorption valve 9, the water input rate and nitrogen nutrient input rate of the left root zone drip irrigation tape 10 and the right root zone drip irrigation tape 11 are controlled in a variable manner, achieving a variable input of soil water and nitrogen in the root zones on both sides of the crop. Alternatively, by reducing the opening time of the left root zone irrigation valve 2 relative to the right root zone irrigation valve 3, and increasing the opening time of the left root zone fertilizer absorption valve 8 relative to the right root zone fertilizer absorption valve 9, the water input time and nitrogen nutrient input time of the left root zone drip irrigation tape 10 and the right root zone drip irrigation tape 11 are controlled in a variable manner, achieving a variable input of soil water and nitrogen in the root zones on both sides of the crop.

[0030] Experimental Example 1

[0031] The flow rates (L / min) of irrigation pump 1 and fertilizer pump 7 are 240 and 2.5, respectively; the concentration of nitrogen fertilizer (urea form: potassium nitrate form = 1:1) in nitrogen fertilizer solution tank 6 is 25 gN / L; the main irrigation pipe 4 in the left root zone and the main irrigation pipe 5 in the right root zone are both 50 meters long and 90 mm in diameter; the drip irrigation tape 10 in the left root zone and the drip irrigation tape 11 in the right root zone are both 13.2 meters long and 16 mm wide, with a drip hole spacing of 15 cm. The nitrate nitrogen content in the irrigation water sourced from groundwater is 56.3 mg / L.

[0032] In a greenhouse with an area of ​​2 mu (approximately 0.33 hectares) intended for planting spring cucumbers, the area was divided into two halves, east and west, each with an area of ​​1 mu (approximately 0.067 hectares). Before planting the cucumbers, three leaching micro-zones, each 2 meters long and 1 meter wide, were arranged on the planting ridges in the east and west halves, taking into account the shallow root distribution of cucumbers. This was done in accordance with the backfill soil infiltration pond method (Liu Hongbin et al. Farmland Non-point Source Pollution Monitoring Methods and Practices. Beijing: Science Press, 2015), to collect leachate from the 0-50 cm soil layer.

[0033] In the east and west halves of the greenhouse, 3000 spring cucumber seedlings were planted in each half at a spacing of 33 cm. Drip irrigation tapes 10 on the left and 11 on the right root zones were symmetrically distributed on both sides of the cucumber planting rows, 15 cm apart. For the first 24 days after transplanting, both halves of the greenhouse received conventional drip irrigation (with identical water and nitrogen input to the root zones on both sides). After this period, the east half of the greenhouse served as a control and continued with conventional drip irrigation, while the west half adopted a drip irrigation system based on the variation of water and nitrogen input to the root zones, but the total water and nitrogen input remained the same in both halves.

[0034] Twenty-seven days after transplanting, the leaching solution in the leaching tank within the leaching microzone was completely removed.

[0035] On days 28, 34, and 40 after transplanting, irrigation and nitrogen application were carried out under different modes according to Table 1. The water input in the left root zone of the water-nitrogen fluctuation treatment was 67% of that in the right root zone, and the nitrogen input in the left root zone was 1.50 times that in the right root zone (Table 1). Leachate was collected on day 42 after cucumber transplanting. Analysis showed that compared with the control treatment, the water leaching loss was reduced by 11.4%, the nitrate nitrogen concentration was reduced by 23.6%, and the nitrate nitrogen leaching amount was reduced by 32.3% in the water-nitrogen fluctuation drip irrigation treatment.

[0036] Table 1 Soil water and nitrogen input in the root zones of cucumbers on both sides under different drip irrigation modes.

[0037]

[0038] The specific procedures for irrigation and nitrogen application according to Table 1 are as follows:

[0039] Control treatment: Open irrigation valve 2 in the left root zone, power on irrigation pump 1, and begin irrigating the soil in the left root zone of the cucumber; after 5 minutes, open fertilizer absorption valve 8 in the left root zone, power on fertilizer absorption pump 7, and begin applying nitrogen to the soil in the left root zone; after 6 minutes, power off fertilizer absorption pump 7, close fertilizer absorption valve 8 in the left root zone, and stop applying nitrogen to the soil in the left root zone; after 5 minutes, open irrigation valve 3 in the right root zone, close irrigation valve 2 in the left root zone, and begin irrigating the soil in the right root zone, and stop irrigating the soil in the left root zone; after 5 minutes, open fertilizer absorption valve 9 in the right root zone, power on fertilizer absorption pump 7, and begin applying nitrogen to the soil in the right root zone; after 6 minutes, power off fertilizer absorption pump 7, close fertilizer absorption valve 9 in the right root zone, and stop applying nitrogen to the soil in the right root zone; after 5 minutes, power off irrigation pump 1, close irrigation valve 3 in the right root zone, and stop irrigating the soil in the right root zone.

[0040] Root zone soil water and nitrogen fluctuation drip irrigation treatment: Open the left root zone irrigation valve 2, turn on irrigation pump 1, and begin irrigating the soil in the left root zone of the cucumber roots; 2 minutes later, open the left root zone fertilizer absorption valve 8, turn on fertilizer absorption pump 7, and begin applying nitrogen to the soil in the left root zone; 8.5 minutes later, turn off fertilizer absorption pump 7, close the left root zone fertilizer absorption valve 8, and stop applying nitrogen to the soil in the left root zone; 1.5 minutes later, open the right root zone irrigation valve 3, close the left root zone irrigation valve 2, and begin irrigating the soil in the right root zone, stopping irrigation to the soil in the left root zone; 8 minutes later, open the right root zone fertilizer absorption valve 9, turn on fertilizer absorption pump 7, and begin applying nitrogen to the soil in the right root zone; 3.5 minutes later, turn off fertilizer absorption pump 7, close the right root zone fertilizer absorption valve 9, and stop applying nitrogen to the soil in the right root zone; 6.5 minutes later, turn off irrigation pump 1, close the right root zone irrigation valve 3, and stop irrigating the soil in the right root zone.

[0041] Experimental Example 2

[0042] The root zone soil water and nitrogen fluctuation drip irrigation device is the same as that in Experiment Example 1.

[0043] The concentration of nitrogen fertilizer (urea nitrogen: potassium nitrate nitrogen = 1:3) in nitrogen fertilizer solution tank 6 is 35 gN / L; other parameters of the irrigation device and the nitrate nitrogen content of irrigation are the same as in Experiment Example 1.

[0044] At 45, 50, and 54 days after transplanting, according to Table 2 (for specific procedures, refer to Experimental Example 1), different water-nitrogen drip irrigation modes were continued for the cucumbers in the eastern and western halves of the greenhouse in Experimental Example 1. The water input in the left root zone of the water-nitrogen fluctuation treatment was 60.3% of that in the right root zone, and the nitrogen input in the left root zone was 1.39 times that in the right root zone (Table 2). Leachate was collected on the 56th day after transplanting. Analysis showed that compared with the control treatment, the water leaching loss was reduced by 7.6%, the nitrate nitrogen concentration was reduced by 20.3%, and the nitrate nitrogen leaching amount was reduced by 26.4% in the water-nitrogen fluctuation drip irrigation treatment.

[0045] Table 2 Soil water and nitrogen input in the root zones of cucumbers under different drip irrigation modes.

[0046]

[0047]

[0048] Experiment Example 3

[0049] The root zone soil water and nitrogen fluctuation drip irrigation device is the same as that in Experiment Example 1.

[0050] The concentration of nitrogen fertilizer (urea nitrogen: potassium nitrate nitrogen = 1:3) in nitrogen fertilizer solution tank 6 is 35 gN / L; other parameters of the irrigation device and the nitrate nitrogen content of irrigation are the same as in Experiment Example 1.

[0051] At 58, 63, and 68 days after cucumber seedling transplanting, water and nitrogen drip irrigation under different modes was continued for cucumbers in the eastern and western halves of the greenhouse in Experiment 1, according to Table 3 (for specific operations, refer to Experiment 1). The water input in the left root zone of the water-nitrogen fluctuation treatment was 64% of that in the right root zone, and the nitrogen input in the left root zone was 1.51 times that in the right root zone (Table 3). Compared with the control treatment, water leaching in the water-nitrogen fluctuation drip irrigation treatment decreased by 5.8% from 58 to 72 days after transplanting, the nitrate nitrogen concentration in the leaching solution decreased by 16.7%, and the nitrate nitrogen leaching amount decreased by 21.5%. From 38 to 75 days after transplanting, cucumber yield increased by 7.6% in the water-nitrogen fluctuation drip irrigation treatment. These results indicate that root zone soil water-nitrogen fluctuation drip irrigation can reduce soil nitrate nitrogen leaching by more than 20% without negatively impacting the yield of greenhouse cucumbers.

[0052] Table 3 Soil water and nitrogen input in the root zones of cucumbers on both sides under different drip irrigation modes.

[0053]

Claims

1. A drip irrigation method for controlling the fluctuation of water and nitrogen in the root zone soil, characterized in that: During drip irrigation, the amount of water input to the soil on the left side of the crop relative to the soil on the right side of the crop is reduced, while the amount of nitrogen nutrient input to the soil on the left side of the crop relative to the soil on the right side of the crop is increased. This achieves a dynamic balance between water and nitrogen input to the soil on both sides of the root zone, thereby regulating the distribution of soil moisture and nitrate nitrogen relative to both sides and reducing the leaching of nitrate nitrogen from the soil.

2. The root zone soil water and nitrogen fluctuation drip irrigation method according to claim 1, characterized in that: The water input to the soil in the left root zone of the crop is 40% to 80% of the water input to the soil in the right root zone.

3. The root zone soil water and nitrogen fluctuation drip irrigation method according to claim 1, characterized in that: The nitrogen nutrient input in the soil of the left root zone of the crop is 1.2 to 3.0 times that in the soil of the right root zone.

4. The root zone soil water and nitrogen fluctuation drip irrigation method according to claim 1, characterized in that: The drip holes in the soil on the left and right sides of the crop root zone are 5 to 20 centimeters away from the crop roots.

5. The root zone soil water and nitrogen fluctuation drip irrigation method according to claim 1, characterized in that: The nitrogen nutrient input to the root zone soil includes the input of nitrogen from fertilizer and the input of nitrogen nutrients contained in the irrigation water itself.

6. A drip irrigation device for implementing the root zone soil water-nitrogen fluctuation drip irrigation method according to any one of claims 1 to 5, characterized in that: The system includes an irrigation pump (1), a left root zone irrigation valve (2), a right root zone irrigation valve (3), a left root zone irrigation main pipe (4), a right root zone irrigation main pipe (5), a nitrogen fertilizer solution tank (6), a fertilizer suction pump (7), a left root zone fertilizer suction valve (8), a right root zone fertilizer suction valve (9), a left root zone drip irrigation tape (10), a right root zone drip irrigation tape (11), a left root zone fertilizer suction pipe (13), and a right root zone fertilizer suction pipe (14). One end of the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5) are respectively connected to the irrigation pump (1), or... One end of the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5) are connected to the irrigation pump (1) through the left root zone irrigation valve (2) and the right root zone irrigation valve (3), respectively. The other end of the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5) are connected to the left root zone drip irrigation tape (10) and the right root zone drip irrigation tape (11), respectively. The left root zone drip irrigation tape (10) and the right root zone drip irrigation tape (11) are respectively arranged on the root zone soil on the left and right sides of the crop roots. When the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5) are connected to the irrigation pump (1), the irrigation pump (11) is connected to the irrigation pump (1). When one end of (5) is connected to the irrigation pump (1), the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5) are respectively equipped with a left root zone irrigation valve (2) and a right root zone irrigation valve (3); the inlet of the fertilizer pump (7) is connected to the nitrogen fertilizer solution tank (6), and one end of the left root zone fertilizer suction pipe (13) and the right root zone fertilizer suction pipe (14) are respectively connected to the outlet of the fertilizer pump (7), or one end of the left root zone fertilizer suction pipe (13) and the right root zone fertilizer suction pipe (14) are respectively connected through the left root zone fertilizer suction valve (8) and the right root zone fertilizer suction pipe (14). The right root zone fertilizer suction valve (9) is connected to the outlet of the fertilizer suction pump (7), and the other ends of the left root zone fertilizer suction pipe (13) and the right root zone fertilizer suction pipe (14) are respectively connected to the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5); when one end of the left root zone fertilizer suction pipe (13) and the right root zone fertilizer suction pipe (14) are respectively connected to the outlet of the fertilizer suction pump (7), the left root zone fertilizer suction pipe (13) and the right root zone fertilizer suction pipe (14) are respectively equipped with a left root zone fertilizer suction valve (8) and a right root zone fertilizer suction valve (9).

7. The drip irrigation device according to claim 6, characterized in that: The outlet of the irrigation pump (1) is connected to one interface of the three-way A (12), and the other two interfaces of the three-way A (12) are respectively connected to one end of the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5), or the other two interfaces of the three-way A (12) are respectively connected to one end of the left root zone irrigation valve (2) and the right root zone irrigation valve (3), and the other ends of the left root zone irrigation valve (2) and the right root zone irrigation valve (3) are respectively connected to one end of the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5).

8. The drip irrigation device according to claim 6, characterized in that: The outlet of the fertilizer pump (7) is connected to one interface of the three-way valve B (15). The other two interfaces of the three-way valve B (15) are respectively connected to one end of the left root zone fertilizer suction pipe (13) and the right root zone fertilizer suction pipe (14). Alternatively, the other two interfaces of the three-way valve B (15) are respectively connected to one end of the left root zone fertilizer suction valve (8) and the right root zone fertilizer suction valve (9). The other ends of the left root zone fertilizer suction valve (8) and the right root zone fertilizer suction valve (9) are respectively connected to one end of the left root zone fertilizer suction pipe (13) and the right root zone fertilizer suction pipe (14).

9. The drip irrigation device according to claim 6, characterized in that: Under the same operating time, reduce the opening degree of the left root zone irrigation valve (2) relative to the right root zone irrigation valve (3), and increase the opening degree of the left root zone fertilizer absorption valve (8) relative to the right root zone fertilizer absorption valve (9), thereby adjusting the water input rate and nitrogen nutrient input rate of the left root zone drip irrigation tape (10) and the right root zone drip irrigation tape (11) in a variable manner, so as to realize the variable input of soil water and nitrogen in the root zones on both sides of the crop; or, reduce the opening time of the left root zone irrigation valve (2) relative to the right root zone irrigation valve (3), and increase the opening time of the left root zone fertilizer absorption valve (8) relative to the right root zone fertilizer absorption valve (9), thereby adjusting the water input time and nitrogen nutrient input time of the left root zone drip irrigation tape (10) and the right root zone drip irrigation tape (11) in a variable manner, so as to realize the variable input of soil water and nitrogen in the root zones on both sides of the crop.

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