Root zone soil water and nitrogen growth reducing type drip irrigation method and drip irrigation device

Abstract

The invention belongs to the field of agricultural production and environmental protection, and particularly relates to a root zone soil water and nitrogen growth reducing type drip irrigation method and a drip irrigation device, in the drip irrigation process, the water input amount of left root zone soil relative to right root zone soil of crops is reduced, and the crop yield is improved. The nitrogen nutrient input quantity of the soil in the left root zone of the crops relative to the soil in the right root zone is increased, the growth-reducing input of water and nitrogen in the soil in the root zones on the two sides is realized, the distribution of the water and nitrate nitrogen in the soil in the root zones on the two sides is regulated in a growth-reducing manner, and the leaching loss of the nitrate nitrogen in the soil is reduced on the premise of not negatively influencing the yield of the crops.

Description

Technical Field

[0001] The present invention belongs to the fields of agricultural production and environmental protection, and particularly relates to a drip irrigation method and a drip irrigation device for the growth and decline of soil water and nitrogen in the root zone. Background Art

[0002] The planting area of protected vegetables in China is 34 million mu, accounting for about 80% of the planting area of protected crops, and the output accounts for more than 25% of the total vegetable output in the country. The production of protected vegetables in China is basically based on soil as the cultivation substrate, and the water and fertilizer measures (including input dosage, frequency, method, etc.) are often not reasonable enough, and nutrient leaching is relatively serious. Among them, nitrate nitrogen is dissolved in the soil solution in the form of anions and is difficult to be adsorbed by the soil, resulting in particularly serious leaching of nitrogen nutrients mainly composed of nitrate nitrogen.

[0003] The water and fertilizer measures mainly affect the soil water leaching and nitrogen nutrient leaching by affecting the temporal and spatial distribution of water and easily migratory nitrogen components mainly composed of nitrate nitrogen in the soil of the crop root zone. During the growth process of protected crops, appropriate water and fertilizer measures (including input dosage, frequency, method, etc.) should be selected in a timely manner to control the soil water and nitrate nitrogen content and their distribution in the root zone of the crop within an appropriate range, so as to meet the growth needs of the crop while controlling the leaching of nitrogen nutrients. Reducing the nitrogen nutrient concentration in the soil leachate under the condition of constant soil water leaching amount, or reducing the water leaching amount under the condition of constant nitrogen nutrient concentration in the soil leachate, or reducing both the soil water leaching amount and the nitrogen nutrient concentration in the soil leachate can all reduce the leaching of soil nitrogen nutrients.

[0004] The production of protected vegetables in China is mainly distributed in the northern regions where the irrigation water is mainly groundwater with a relatively high salt content. If the water-saving irrigation technology mainly based on integrated water and fertilizer drip irrigation is adopted, it is mostly combined with the measure of "washing salt with large amounts of water" to prevent and control soil salt damage. In fact, it does not achieve good water conservation, nor does it well control the loss of nitrogen nutrients. Split-root irrigation, as a water-saving irrigation technology, is generally used for open-field crops in water-scarce areas, especially suitable for fruit trees and wide-row crops for furrow irrigation, and its application in protected vegetable production is very limited. The reasons are as follows: on the one hand, it also often needs to be combined with the measure of "washing salt with large amounts of water" to control soil salt damage; on the other hand, it is not easy to achieve stable production of protected crops, especially for protected vegetables with large water consumption, such as cucumbers. On the contrary, the integrated water and fertilizer constant drip irrigation that does not particularly emphasize water conservation can better control soil salt damage and fertilizer damage and stabilize crop yields, and is widely used in the production of protected vegetables in China.

[0005] However, under the constant drip irrigation method of integrated water and fertilizer, the leaching of nitrogen nutrients mainly in the form of nitrate nitrogen is still relatively serious, generally not less than 30%. It is very necessary to develop a new type of water and fertilizer drip irrigation technology to better control the leaching of nitrogen nutrients mainly in the form of nitrate nitrogen and promote the green production of protected agriculture. For the production of protected vegetables with large water consumption and serious nitrogen nutrient loss, such as the production of greenhouse cucumbers, such a demand is even more urgent. Summary of the Invention

[0006] In view of the above problems existing in the existing integrated water and fertilizer drip irrigation, the purpose of the present invention is to provide a drip irrigation method and a drip irrigation device for the growth and decline of soil water and nitrogen in the root zone.

[0007] The purpose of the present invention is achieved by the following technical solutions:

[0008] The drip irrigation method for the growth and decline of soil water and nitrogen in the root zone of the present invention is that during the drip irrigation process, the water input amount of the soil in the left root zone of the crop is reduced relative to the soil in the right root zone of the crop, and the nitrogen nutrient input amount of the soil in the left root zone of the crop is increased relative to the soil in the right root zone of the crop, so as to realize the growth and decline type input of soil water and nitrogen in both root zones, regulate the distribution of soil water and nitrate nitrogen in the root zone relative to both sides in a growth and decline manner, and reduce the leaching of soil nitrate nitrogen.

[0009] Among them: the water input amount of the soil in the left root zone of the crop is 40% - 80% of the water input amount of the soil in the right root zone of the crop.

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

[0011] The distance between the drip hole sites of the soil in the left root zone and the right root zone of the crop from the root of the crop is 5 - 20 cm.

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

[0013] The drip irrigation device for implementing the root zone soil water and nitrogen growth and decline type drip irrigation method of the present invention 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 pool, a fertilizer suction pump, a left root zone fertilizer suction valve, a right root zone fertilizer suction valve, a left root zone drip irrigation belt, a right root zone drip irrigation belt, a left root zone fertilizer suction pipeline and a right root zone fertilizer suction pipeline. One end of the left root zone irrigation main pipe and the right root zone irrigation main pipe are respectively connected to the irrigation pump, or one end of the left root zone irrigation main pipe and the right root zone irrigation main pipe are respectively connected to the irrigation pump through the left root zone irrigation valve and the right root zone irrigation valve. The other ends of the left root zone irrigation main pipe and the right root zone irrigation main pipe are respectively communicated with the left root zone drip irrigation belt and the right root zone drip irrigation belt. The left root zone drip irrigation belt and the right root zone drip irrigation belt are respectively arranged on the left and right root zone soils of the crop roots. When one end of the left root zone irrigation main pipe and the right root zone irrigation main pipe are respectively connected to the irrigation pump, the left root zone irrigation valve and the right root zone irrigation valve are respectively arranged on the left root zone irrigation main pipe and the right root zone irrigation main pipe. The water inlet of the fertilizer suction pump is communicated with the nitrogen fertilizer solution pool. One end of the left root zone fertilizer suction pipeline and the right root zone fertilizer suction pipeline are respectively connected to the water outlet of the fertilizer suction pump, or one end of the left root zone fertilizer suction pipeline and the right root zone fertilizer suction pipeline are respectively connected to the water outlet of the fertilizer suction pump through 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 pipeline and the right root zone fertilizer suction pipeline are respectively communicated with 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 pipeline and the right root zone fertilizer suction pipeline are respectively connected to the water outlet of the fertilizer suction pump, the left root zone fertilizer suction valve and the right root zone fertilizer suction valve are respectively arranged on the left root zone fertilizer suction pipeline and the right root zone fertilizer suction pipeline.

[0014] Wherein: the water outlet of the irrigation pump is communicated with one interface of a tee A. 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. 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 water outlet of the fertilizer suction pump is communicated with one interface of a tee B. The other two interfaces of the tee B are respectively connected to one end of the left root zone fertilizer suction pipeline and the right root zone fertilizer suction pipeline, or the other two interfaces 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 pipeline and the right root zone fertilizer suction pipeline.

[0016] Under the condition of the same running time, reduce the opening degree of the irrigation valve in the left root zone relative to that in the right root zone, and increase the opening degree of the fertilizer absorption valve in the left root zone relative to that in the right root zone, so as to adjust the water input rate and nitrogen nutrient input rate of the drip irrigation belts in the left and right root zones in a growth and decline manner, and realize the growth and decline input of soil water and nitrogen in the root zones on both sides of the crop; or, reduce the opening time of the irrigation valve in the left root zone relative to that in the right root zone, and increase the opening time of the fertilizer absorption valve in the left root zone relative to that in the right root zone, so as to adjust the water input time and nitrogen nutrient input time of the drip irrigation belts in the left and right root zones in a growth and decline manner, and realize the growth and decline input of soil water and nitrogen in the root zones on both sides of the crop.

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

[0018] 1. On the premise of the same water input amount and the same nitrogen input amount, compared with the constant drip irrigation of integrated water and fertilizer, the present invention can adjust the input amounts of soil water and nitrogen in the root zones on both sides of the crop in a growth and decline manner, and adjust the distribution of soil moisture and nitrate nitrogen in the root zones relative to both sides, so as to reduce the concentration of nitrate nitrogen in the soil leaching solution without reducing the water leaching amount, and realize the reduction of nitrogen leaching amount.

[0019] 2. Compared with the split-root irrigation with reduced irrigation amount, the present invention does not need to worry about the problem that the soil in some root zones is too dry and affects the crop yield, nor does it need to worry too much about the problem that the high salinity of irrigation water aggravates the soil salt damage; the drip irrigation method of the present invention is applicable to the production of crops with large water consumption and certain drought tolerance (such as tomatoes), and is more applicable to the production of crops with large water consumption and less drought tolerance (such as cucumbers). Description of the Drawings

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

[0021] Among them: 1 is an irrigation pump, 2 is an irrigation valve in the left root zone, 3 is an irrigation valve in the right root zone, 4 is a main irrigation pipe in the left root zone, 5 is a main irrigation pipe in the right root zone, 6 is a nitrogen fertilizer solution tank, 7 is a fertilizer absorption pump, 8 is a fertilizer absorption valve in the left root zone, 9 is a fertilizer absorption valve in the right root zone, 10 is a left root drip irrigation belt, 11 is a right root zone drip irrigation belt, 12 is a tee A, 13 is a fertilizer absorption pipe in the left root zone, 14 is a fertilizer absorption pipe in the right root zone, and 15 is a tee B. Detailed Embodiment

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

[0023] The method of variable input of soil water and nitrogen in the root zone of the present invention is as follows: during drip irrigation, reduce the water input amount of the soil in the left root zone of the crop relative to the soil in the right root zone of the crop, and increase the nitrogen nutrient input amount of the soil in the left root zone of the crop relative to the soil in the right root zone of the crop, so as to achieve variable input of soil water and nitrogen in the two root zones, variably regulate the distribution of soil water and nitrate nitrogen in the root zone relative to both sides, and reduce the leaching of soil nitrate nitrogen.

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

[0025] In this embodiment, the water input amount of the soil in the left root zone of the crop is 40% - 80% of the water input amount of the soil in the right root zone of the crop, the nitrogen nutrient input amount of the soil in the left root zone of the crop is 1.2 - 3.0 times that of the soil in the right root zone of the crop, and the distance between the drip hole sites of the soil in the left root zone and the right root zone of the crop from the root of the crop is 5 - 20 cm.

[0026] Such as Figure 1As shown in the figure, the device for the growth and decline of soil water and nitrogen in the root zone 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 belt 10, a right root zone drip irrigation belt 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 is 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 is respectively connected to the irrigation pump 1 through the left root zone irrigation valve 2 and the right root zone irrigation valve 3. The other ends of the left root zone irrigation main pipe 4 and the right root zone irrigation main pipe 5 are respectively communicated with the left root zone drip irrigation belt 10 and the right root zone drip irrigation belt 11. The left root zone drip irrigation belt 10 and the right root zone drip irrigation belt 11 are respectively arranged on the soil of the left and right root zones of the crop roots; when one end of the left root zone irrigation main pipe 4 and the right root zone irrigation main pipe 5 is respectively 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 provided with the left root zone irrigation valve 2 and the right root zone irrigation valve 3. The water inlet of the fertilizer suction pump 7 is communicated with 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 is respectively connected to the water outlet of the fertilizer suction pump 7, or one end of the left root zone fertilizer suction pipe 13 and the right root zone fertilizer suction pipe 14 is respectively connected to the water outlet of the fertilizer suction pump 7 through 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 pipe 13 and the right root zone fertilizer suction pipe 14 are respectively communicated with 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 is respectively connected to the water 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 provided with the left root zone fertilizer suction valve 8 and the right root zone fertilizer suction valve 9.

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

[0028] The water outlet of the fertilizer suction pump 7 is communicated with one interface of the tee B15. The other two interfaces of the tee B15 are respectively connected to one end of the left root zone fertilizer suction pipeline 13 and the right root zone fertilizer suction pipeline 14, or the other two interfaces of the tee B15 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 pipeline 13 and the right root zone fertilizer suction pipeline 14. In this embodiment, the water outlet of the fertilizer suction pump 7 is communicated with the first interface of the tee B15. The second interface of the tee B15 is connected to one end of the left root zone fertilizer suction pipeline 13. The left root zone fertilizer suction valve 8 is provided on the left root zone fertilizer suction pipeline 13. The third interface of the tee B15 is connected to one end of the right root zone fertilizer suction pipeline 14. The right root zone fertilizer suction valve 9 is provided on the right root zone fertilizer suction pipeline 14.

[0029] Under the condition of the same running 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 suction valve 8 relative to the right root zone fertilizer suction valve 9, and regulate the water input rate and nitrogen nutrient input rate of the left root zone drip irrigation belt 10 and the right root zone drip irrigation belt 11 in a growth and decline manner to achieve the growth and decline 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 suction valve 8 relative to the right root zone fertilizer suction valve 9, and regulate the water input time and nitrogen nutrient input time of the left root zone drip irrigation belt 10 and the right root zone drip irrigation belt 11 in a growth and decline manner to achieve the growth and decline 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 / minute) of the irrigation pump 1 and the fertilizer suction pump 7 are 240 and 2.5 respectively; the concentration of nitrogen fertilizer (urea form: potassium nitrate form = 1:1) in the nitrogen fertilizer solution pool 6 is 25 gN / L; the left root zone irrigation main pipe 4 and the right root zone irrigation main pipe 5 are both 50 meters long and 90 mm in diameter; the left root zone drip irrigation belt 10 and the right root zone drip irrigation belt 11 are both 13.2 meters long, 16 mm wide, and the drip hole spacing is 15 cm. The nitrate nitrogen content in the irrigation water from the groundwater source is 56.3 mg / L.

[0032] In a greenhouse with an area of 2 mu and intended to plant spring cucumber, it is divided into two half-areas in the east and west, each with an area of 1 mu. Before planting cucumbers, three leaching micro-zones with a length of 2 meters and a width of 1 meter are arranged on the planting ridges in the east and west half-areas, considering the characteristics of the relatively shallow root distribution of cucumbers, with reference to the backfill soil type leakage pond method (Liu Hongbin et al. Monitoring Methods and Practices of Farmland Non-point Source Pollution. Beijing: Science Press, 2015), for collecting the leaching solution in the 0-50 cm soil layer.

[0033] In the east and west halves of the greenhouse, 3,000 spring cucumber seedlings were respectively planted at a plant spacing of 33 cm. The left root zone drip irrigation tape 10 and the right root zone drip irrigation tape 11 are 15 cm apart and are symmetrically distributed on the left and right sides of the cucumber planting row. Within 24 days after cucumber planting, both the east and west halves of the greenhouse were under conventional drip irrigation (the soil water and nitrogen input in both root zones were the same). After that, the east half of the greenhouse, as a control treatment, still adopted conventional drip irrigation, while the west half of the greenhouse adopted root zone soil water and nitrogen fluctuation drip irrigation, but the total water input and total nitrogen input in both halves were the same.

[0034] On the 27th day after planting, the leaching solution in the leaching bucket in the leaching microzone was completely removed.

[0035] On the 28th, 34th, and 40th days after planting, according to Table 1, irrigation and nitrogen application treatments were carried out under different modes. The water input in the left root zone of the water and 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). The leaching solution was collected on the 42nd day after cucumber planting, and the analysis showed that compared with the control treatment, the water leaching in the water and nitrogen fluctuation drip irrigation treatment decreased by 11.4%, the nitrate nitrogen concentration decreased by 23.6%, and the nitrate nitrogen leaching amount decreased by 32.3%.

[0036] Table 1 Soil water and nitrogen input in the left and right root zones of cucumbers under different drip irrigation modes

[0037]

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

[0039] Control treatment: Open the irrigation valve 2 in the left root zone, turn on the irrigation pump 1, and start irrigating the soil in the left root zone of the cucumber roots; after 5 minutes, open the fertilizer suction valve 8 in the left root zone, turn on the fertilizer suction pump 7, and start applying nitrogen to the soil in the left root zone; after 6 minutes, turn off the fertilizer suction pump 7, close the fertilizer suction valve 8 in the left root zone, and stop applying nitrogen to the soil in the left root zone; after 5 minutes, open the irrigation valve 3 in the right root zone, close the irrigation valve 2 in the left root zone, and start irrigating the soil in the right root zone, stopping irrigating the soil in the left root zone; after 5 minutes, open the fertilizer suction valve 9 in the right root zone, turn on the fertilizer suction pump 7, and start applying nitrogen to the soil in the right root zone; after 6 minutes, turn off the fertilizer suction pump 7, close the fertilizer suction valve 9 in the right root zone, and stop applying nitrogen to the soil in the right root zone; after 5 minutes, turn off the irrigation pump 1, close the 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 growth and decline type drip irrigation treatment: Open the left root zone irrigation valve 2, power on the irrigation pump 1, and start irrigating the soil in the left root zone of the cucumber roots; after 2 minutes, open the left root zone fertilizer suction valve 8, power on the fertilizer suction pump 7, and start applying nitrogen to the soil in the left root zone; after 8.5 minutes, power off the fertilizer suction pump 7, close the left root zone fertilizer suction valve 8, and stop applying nitrogen to the soil in the left root zone; after 1.5 minutes, open the right root zone irrigation valve 3, close the left root zone irrigation valve 2, start irrigating the soil in the right root zone, and stop irrigating the soil in the left root zone; after 8 minutes, open the right root zone fertilizer suction valve 9, power on the fertilizer suction pump 7, and start applying nitrogen to the soil in the right root zone; after 3.5 minutes, power off the fertilizer suction pump 7, close the right root zone fertilizer suction valve 9, and stop applying nitrogen to the soil in the right root zone; after 6.5 minutes, power off the 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 growth and decline type drip irrigation device is the same as that in Experimental Example 1.

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

[0044] On the 45th, 50th, and 54th days after the cucumber seedlings were planted, according to Table 2 (for specific operations, refer to Experimental Example 1), continue to carry out water and nitrogen drip irrigation in different modes for the cucumbers in the east and west halves of the greenhouse in Experimental Example 1. The water input in the left root zone under the water and nitrogen growth and decline treatment is 60.3% of that in the right root zone, and the nitrogen input in the left root zone is 1.39 times that in the right root zone (Table 2). The leaching solution was collected on the 56th day after the cucumber seedlings were planted. The analysis shows that compared with the control treatment, the water leaching under the water and nitrogen growth and decline drip irrigation treatment is reduced by 7.6%, the nitrate nitrogen concentration is reduced by 20.3%, and the nitrate nitrogen leaching amount is reduced by 26.4%.

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

[0046]

[0047]

[0048] Experimental Example 3

[0049] The root zone soil water and nitrogen growth and decline type drip irrigation device is the same as that in Experimental Example 1.

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

[0051] At 58, 63, and 68 days after the cucumber seedlings were transplanted, according to Table 3 (for specific operations, refer to Experimental Example 1), different modes of water and nitrogen drip irrigation were continued for the cucumbers in the east and west halves of the greenhouse in Experimental Example 1. The water input in the left root zone of the water-nitrogen growth and decline 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, during the period from 58 to 72 days after cucumber transplantation, the water leaching in the water-nitrogen growth and decline drip irrigation treatment decreased by 5.8%, the nitrate-nitrogen concentration in the leaching solution decreased by 16.7%, and the nitrate-nitrogen leaching amount decreased by 21.5%. During the period from 38 to 75 days after cucumber transplantation, the cucumbers in the water-nitrogen growth and decline drip irrigation treatment increased in yield by 7.6%. The above results show that root-zone soil water-nitrogen growth and decline drip irrigation can reduce the nitrate-nitrogen leaching amount in the soil by more than 20% without negatively affecting the yield of greenhouse cucumbers.

[0052] Table 3 Soil water and nitrogen input in the left and right root zones of cucumbers under different drip irrigation modes

[0053]

Claims

1. A method for drip irrigation with varying water and nitrogen levels in the root zone soil, characterized in that: During drip irrigation, the water input to the soil in the left root zone of the crop is reduced relative to the soil in the right root zone of the crop, and the nitrogen nutrient input to the soil in the left root zone of the crop is increased relative to the soil in the right root zone of the crop, so as to achieve a varying input of water and nitrogen in the two root zone soils, regulate the distribution of soil water and nitrate nitrogen in the root zone relative to both sides, and reduce the leaching of soil nitrate nitrogen.

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

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

4. The method for drip irrigation with varying water and nitrogen levels in the root zone soil according to claim 1, characterized in that: The distance between the drip hole sites in the soil of the left root zone and the right root zone of the crop from the root of the crop is 5 - 20 cm.

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

6. A drip irrigation device for implementing the method for drip irrigation with varying water and nitrogen levels in the root zone soil according to any one of claims 1 to 5, characterized in that: It 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 respectively connected to the irrigation pump (1) through the left root zone irrigation valve (2) and the right root zone irrigation valve (3). The other ends of the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5) are respectively communicated with a left root zone drip irrigation tape (10) and a right root zone drip irrigation tape (11). The left root zone drip irrigation tape (10) and the right root zone drip irrigation tape (11) are respectively arranged on the soil of the left and right root zones of the crop roots; when 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), the left root zone irrigation main pipe (4) and the right root zone irrigation main pipe (5) are respectively provided with a left root zone irrigation valve (2) and a right root zone irrigation valve (3); the water inlet of the fertilizer suction pump (7) is communicated with 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 water outlet of the fertilizer suction 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 water outlet of the fertilizer suction pump (7) through 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 pipe (13) and the right root zone fertilizer suction pipe (14) are respectively communicated with 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 water 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 provided 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 water outlet of the irrigation pump (1) is communicated with one interface of a tee A (12). The other two interfaces of the tee 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 tee A (12) are respectively connected to one end of the left root zone irrigation valve (2) and the right root zone irrigation valve (3). 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 water outlet of the fertilizer suction pump (7) is communicated with one interface of the tee joint B (15). The other two interfaces of the tee joint B (15) are respectively connected to one ends of the left root zone fertilizer suction pipeline (13) and the right root zone fertilizer suction pipeline (14), or the other two interfaces of the tee joint B (15) are respectively connected to one ends 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 ends of the left root zone fertilizer suction pipeline (13) and the right root zone fertilizer suction pipeline (14).

9. The drip irrigation device according to claim 6, characterized in that: Under the condition of the same operation 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 suction valve (8) relative to the right root zone fertilizer suction valve (9), and adjust the water input rate and nitrogen nutrient input rate of the left root zone drip irrigation belt (10) and the right root zone drip irrigation belt (11) in a growth and decline manner to achieve the growth and decline 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 suction valve (8) relative to the right root zone fertilizer suction valve (9), and adjust the water input time and nitrogen nutrient input time of the left root zone drip irrigation belt (10) and the right root zone drip irrigation belt (11) in a growth and decline manner to achieve the growth and decline input of soil water and nitrogen in the root zones on both sides of the crop.

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