Greenhouse saline-alkali soil continuous desalting method and application

Abstract

The invention provides a greenhouse saline-alkali soil continuous desalting method and application, and belongs to the technical field of saline-alkali soil improvement and agricultural facility engineering. The greenhouse is covered with shading objects, soil in the greenhouse is subjected to one-time sufficient irrigation, soil salinity is leached, and the salinity requirement of fruits and vegetables planted in the greenhouse is met. According to the method, salt in a greenhouse is actively pumped out of the greenhouse through a synergistic mechanism of'irrigation for salt inhibition in the greenhouse, evaporation for salt accumulation outside the greenhouse and biological absorption for salt elimination 'by utilizing a strong soil-water potential energy difference generated by water, temperature and salt differences in the greenhouse and outside the greenhouse, and a synergistic desalting effect of' 1 + 1gt, 2 'is generated. The whole process is driven only through conventional irrigation and natural solar energy, water resources are greatly saved, and the expensive investment of a concealed pipe salt discharging system is omitted.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of saline-alkali soil improvement and agricultural facility engineering, and particularly relates to a method for continuously desalinating greenhouse saline-alkali soil and application. BACKGROUND

[0002] Some regions are rich in light and heat resources, but the soil has the problem of salinization, which seriously restricts the development of modern agriculture. Building a sunlight greenhouse is an important way to efficiently utilize light and heat resources, but direct construction on saline-alkali soil faces the following core contradictions: 1) the initial salt content of the soil is high, and crops are difficult to grow; 2) the closed environment of the greenhouse and irrigation easily lead to salt accumulation, causing secondary salinization.

[0003] Traditional improvement methods such as large-scale flooding to wash salt require a large amount of scarce fresh water resources, and need to be matched with an expensive underground drainage system, which is costly. A single biological desalination method, such as planting salt-tolerant plants, is more environmentally friendly, but the desalination speed is slow, the period is long, and it is difficult to meet the demand for rapid production of facility agriculture. Therefore, there is an urgent need for a comprehensive method that combines rapid desalination, water and energy saving, and facility agriculture construction. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a method for continuously desalinating greenhouse saline-alkali soil and application. By designing a clever "in-shed irrigation salt suppression-out-shed evaporation salt accumulation-biological absorption salt discharge" synergistic mechanism, fruits and vegetables are produced while the salt content of the soil in the shed is rapidly, efficiently and cost-effectively reduced.

[0005] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions: The present application provides a method for continuously desalinating greenhouse saline-alkali soil, comprising the following steps: After the greenhouse is shaded to a light transmittance of 30% to 70%, the entire area inside and outside the greenhouse is irrigated once, and salt-tolerant plants are planted outside the greenhouse. The irrigation amount is 50 to 500 m 3 / mu.

[0006] Preferably, the method for shading the greenhouse comprises covering the greenhouse with a shading object.

[0007] Preferably, the shading object comprises a light-transmitting non-woven fabric or a sunshade net.

[0008] Preferably, the salt-tolerant plants comprise Suaeda salsa, Salicornia bigelovii, Limonium bicolor, Spinacia oleracea or Spinacia oleracea.

[0009] Preferably, before the salt-tolerant plants are planted outside the greenhouse, a ditch is also dug, the depth of the ditch is 30 to 50 cm, and the width of the ditch is 30 to 70 cm.

[0010] Preferably, the planting position of the halophyte comprises both sides of a ditch.

[0011] Preferably, the planting comprises sowing or transplanting.

[0012] Preferably, after the one-time irrigation, the conventional crops in the greenhouse are subjected to daily irrigation management.

[0013] The application provides application of the method in improving the yield of crops in saline-alkali land.

[0014] Compared with the prior art, the application has the following beneficial effects: The application provides a greenhouse saline-alkali soil continuous desalination method and application, through pre-covering on a greenhouse, the light transmittance is controlled at 30-70%, sufficient irrigation is carried out on the land in the greenhouse including the pre-covered greenhouse and the land between the greenhouses planted with halophytic plants, due to the flooding irrigation, the irrigation water carries the soluble salt under the gravity and leaches downward, after the soil salt in the greenhouse reaches the standard, fruits and vegetables are planted according to the conventional method. Due to the daily irrigation management in the greenhouse, the soil in the greenhouse forms a relatively "low evaporation potential" area. And the area between the greenhouses is directly exposed to strong sunlight, the soil water is strongly evaporated, forming a strong "high evaporation potential" area, the potential difference is formed between the greenhouse and the area between the greenhouses, which becomes the "dry salt discharge" power source. The evaporation potential difference will produce a significant water potential gradient, causing the lateral migration of the soil capillary water in the adjacent greenhouse. Since the salt is dissolved in water, the leached salt in the greenhouse is continuously transported laterally to the root zone of the halophytic plants in the area between the greenhouses. The strong water evaporation makes the area between the greenhouses become a salt accumulation area, the salt in the root zone is absorbed by the halophytic plants and enriched in the tissues. By regularly harvesting the halophytic plants in the growing season, the plant bodies rich in salt are removed from the land, so that the permanent removal of salt is realized. The process is circular, which ensures that the soil electrical conductivity in the greenhouse decreases to the target threshold suitable for the growth of fruits and vegetables. The technical scheme of the application utilizes the strong soil water potential difference generated by the water, temperature and salt difference between the greenhouse and the outside, actively "extracts" the salt in the greenhouse to the outside, compared with the simple biological desalination, the efficiency is greatly improved. The application first couples the water-salt movement law "salt comes with water, salt goes with water" and the biological salt absorption capacity of the Suaeda salsa, which is a physical principle, to produce a "1+1>2" synergistic desalination effect, and the desalination speed is much faster than a single technology. The strong evaporation in the area between the greenhouses actively "extracts" the salt in the greenhouse, changes the passive "salt washing" to the active "salt discharge", the salt is directionally transported, the direction is clear, and the efficiency is higher. Without a large amount of fresh water for repeated flushing, only relying on conventional irrigation and natural solar energy to drive the whole process, the water resources are greatly saved, which meets the requirements of sustainable development of agriculture in arid areas. The investment of the expensive underground pipe salt discharge system is also saved, the salt removal is realized by using the halophytic plants, and the operation cost is low. The application realizes the win-win of ecology and economy, including the economic benefits of the harvested products of the halophytic plants, and realizes the value increment of the improvement process, such as the seedlings as vegetables, the mature bodies as feed or biological salt raw materials. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a schematic diagram of the system structure principle of the method of the application, wherein 1 is a sunlight greenhouse, 2 is the downward leaching of the soil salt in the greenhouse, 3 is the land between the greenhouses, 4 is the salt absorption of the halophytic plants, 5 is the soil low potential area, 6 is the soil high potential area, 7 is the lateral migration direction of the soil water and salt, 8 is the strong evaporation effect. The potential area described herein is the water and soil potential, including the matrix potential + solute potential + gravity potential + pressure potential.

[0016] Figure 2The system structure of the method is shown in the figure, from left to right, it is a plant of Suaeda salsa, a Suaeda salsa planted in the inter-shed field is in a branching period, and a Suaeda salsa planted in the inter-shed field is in a seed setting period. DETAILED DESCRIPTION

[0017] The application provides a greenhouse saline-alkali soil continuous desalination method, which comprises the following steps: After the sunlight transmittance of the greenhouse is 30-70%, the whole area in and outside the greenhouse is irrigated once, and then the halophyte is planted outside the greenhouse. In the application, the greenhouse is used to plant fruits and vegetables according to local crops (for example, spring early cucumber-autumn late tomato-overwintering), and after the fruits and vegetables are planted, the shading curtain of the greenhouse is taken down.

[0018] In the application, the sunlight transmittance after shading is 30-70%, preferably 40-60%, and more preferably 50%; the halophyte is planted outside the greenhouse; the shading object preferably comprises light-transmitting non-woven fabric, sunshade net, cotton quilt or straw curtain; the halophyte is preferably Suaeda salsa, Salicornia, Limonium bicolor, Spinacia oleracea or Spinach, and more preferably Suaeda salsa; the planting time of the halophyte is preferably from April to October.

[0019] In the application, a ditch is preferably dug outside the greenhouse, on the one hand, the ditch can be used to avoid salt to ensure the emergence rate of the halophyte, and on the other hand, the halophyte can survive by relying on natural precipitation in the ditch; if the ditch is not dug, the halophyte can survive by relying on underground water supply and natural precipitation and a small amount of artificial irrigation; the depth of the ditch is preferably 20-60 cm, more preferably 30-50 cm, and more preferably 40 cm; the width of the ditch is preferably 30-70 cm, more preferably 40-60 cm, and more preferably 50 cm; the planting position of the halophyte is preferably on both sides of the ditch.

[0020] In the application, the method for planting the halophyte preferably comprises sowing or transplanting, after the halophyte emerges, a small amount of irrigation is preferably performed to the seedling stage, the irrigation interval is preferably 5-10 days, more preferably 6-8 days, and more preferably 7 days; the irrigation amount of each time is preferably 10-20 m 3 , more preferably 12-18 m 3 , and more preferably 15 m 3 ; after the halophyte grows into seedlings, the halophyte can survive by relying on underground water supply and natural precipitation.

[0021] In the application, the whole area in and outside the greenhouse is irrigated once, and the irrigation amount is preferably 50-500 m 3 / mu, and more preferably 100-300 m 3further preferably 200 m 3 / acre. After the one-time irrigation, the conventional crops in the greenhouse are managed by daily irrigation.

[0022] The application provides application of the method in improving yield of crops in saline-alkali soil.

[0023] The technical solutions provided by the application will be described in detail below in combination with examples, but they cannot be understood as limitations to the protection scope of the application.

[0024] Example 1

[0025] In the modern agricultural industry park of Bachu County in Kashi (the initial soil electrical conductivity ECe is 8-10 dS / m).

[0026] S1: 10 acres of saline-alkali land are leveled, and 5 east-west running solar greenhouses with an area of about 1 acre each are planned and constructed, the width of the land between the greenhouses is 4-6 meters, and the length is the same as that of the greenhouse. The greenhouse steel frame structure is built, and cotton is provided.

[0027] S2: After the construction of the solar greenhouse, the soil salt content is high, and fruits and vegetables cannot be planted. At this time, the drip irrigation system is used to irrigate the soil in the greenhouse once with a large fixed amount, and the irrigation amount is 50 m 3 / acre, and at the same time, the cotton is covered on the greenhouse to reduce water evaporation and leach the soil salt in the greenhouse to meet the salt requirement for tomato planting.

[0028] S3: In early April, the inter-plot land is furrowed and the seed of Salicornia bigelovii is sown, and then it is slightly pressed after sowing. The sowing amount is 1-1.5 kg / acre.

[0029] S4: The inter-plot land is irrigated by using the drip irrigation system, and the irrigation fixed amount is 15 m 3 / acre. After the seedling of Salicornia bigelovii, irrigation is carried out once every 7 days, and irrigation is carried out 3 times, and after the seedling, irrigation is no longer carried out (Salicornia bigelovii survives by relying on groundwater recharge and natural precipitation).

[0030] S5: At the same time, the tomato variety “Shen 048 tomato” is planted in the greenhouse in a timely manner, and subsequently, according to the light conditions and the needs of crop growth, cotton is used, and the total irrigation amount is about 300-600 m 3 / acre according to the conventional water and fertilizer management system in Xinjiang region in the whole growth period. Due to the great difference in soil water potential caused by irrigation, water moves to the high potential area, “salt follows water”, and the soil water in the inter-plot land continuously evaporates under the action of evaporation and transpiration, and the salt is accumulated in the inter-plot land.

[0031] S6: The Salicornia bigelovii is cut once a month, and the harvested plants are removed from the land. The soil EC value in the greenhouse is monitored every month. The Salicornia bigelovii in the inter-plot land is continuously managed and harvested.

[0032] S7: After about 5 months of operation, the ECe of the 0-40cm plough layer soil in the shed is reduced to below 2.0 dS / m. The schematic diagram of the system structure principle profile of the method of the application is shown in Figure 1 , Figure 2 is a real scene diagram.

[0033] In addition, the planting method of a conventional sunlight greenhouse is selected for comparison, wherein the cultivation method of the conventional sunlight greenhouse is as follows: the conventional greenhouse refers to a sunlight greenhouse without reserved plots between sheds and without planting of halophytes, and the fixed water irrigation is 150 m 3 . The shed planting management measures are consistent with those of the application. The results are shown in Table 1.

[0034] The results show that the method of the application saves water by about 66.67% compared with the traditional salt washing method, shortens the desalination time by about 46.67%, and no salt damage phenomenon occurs in the first year of tomato planting in the shed, and good economic and social benefits are achieved. The results are shown in Table 1.

[0035] Table 1: Use effect of different sunlight greenhouses

[0036] Example 2

[0037] The implementation site and conditions are as follows: the implementation site is in Ruoqiang County, Kashi Region, Xinjiang, which is a heavy saline-alkali wasteland, the soil pH value is 7.8, the average salt content (EC value) of the 0-20cm surface soil is 10.25 g / kg, the groundwater mineralization degree is high, and the annual average evaporation is much greater than the precipitation.

[0038] Specific implementation steps are as follows: S1: Ten standardized sunlight greenhouses (each shed is 100m long and 10m wide) are constructed, the width of the reserved plots between the sheds is 4-8m, and the length is the same as that of the greenhouse shed. The greenhouse steel frame structure is built, and the sunshade net is provided to control the light transmittance to be 30%-50%. The steps are similar to those of Example 1.

[0039] S2: The water irrigation amount is 100 m 3 / mu, and the salt content of the soil in the shed is leached to meet the salt content requirement for tomato planting (2.50 g / kg or less, which is the condition for planting tomatoes, cucumbers and other conventional vegetables and fruits).

[0040] S3: In early April, a 40cm-deep and 50cm-wide ditch ridge is dug in the plot between the sheds. The ditch soil is naturally accumulated into a ridge, and the halophyte Puccinellia tenuiflora seeds are densely sown in the ditch by mechanical drilling to ensure the seedling emergence rate of the halophyte Puccinellia tenuiflora.

[0041] S4: The plot between the sheds is provided with a drip irrigation system, and the irrigation amount is 20 m 3The saline Suaeda plants are irrigated every 7 days after germination, and the irrigation is performed 3 times, and irrigation is not performed after seedling.

[0042] S5: The salt-resistant tomato variety "Jinpeng 10" is transplanted in the greenhouse at a time according to the local crop connection time, and the total irrigation amount during the whole growth period is about 400-600 m 3 The soil water potential gradient in the greenhouse causes lateral migration of water and salt, and the soil moisture in the field outside the greenhouse evaporates continuously under the action of evaporation and transpiration, and the salt is accumulated in the field between the greenhouses.

[0043] S6: 3-4 crops of the saline Suaeda plants are harvested in the field outside the greenhouse during the whole growth season (April-October), and the plants are harvested as forage at the end of the growth period.

[0044] S7: The soil salt in the greenhouse is monitored every month by using a soil conductivity meter. In the fourth month, the monitoring data shows that the soil EC value in the greenhouse has stabilized at 2.80 dS / m.

[0045] 4. Implementation effect: Desalination efficiency: The soil salt in the greenhouse is reduced from 10.25 g / kg to 2.80 g / kg (statistical during the tomato harvesting period, at this time, the irrigation water amount is reduced, and the soil is slightly salted), and the desalination rate is 73.04%.

[0046] Water resource saving: Compared with the traditional large water flooding and salt washing (about 200 m 3 / acre), the water saving rate of the method is more than 50%.

[0047] Economic benefit: The yield of the tomatoes planted in the same year reaches 2375.63 / acre, which is close to the yield level of the greenhouse in the non-saline alkali soil in the local area. At the same time, the harvested dry grass of the saline Suaeda is sold as forage, which partly offsets the early investment.

[0048] The use effect of the sunlight greenhouse, the use effect of the conventional sunlight greenhouse (Example 1) and the use effect of the non-saline alkali soil greenhouse are compared.

[0049] Table 2 Use effect of different sunlight greenhouses

[0050] Example 3

[0051] Implementation place and condition: The average salt content (EC value) of the 0-20 cm surface soil in the 224th team of the Hotan area in Xinjiang is 7-9 dS / m. It is hoped that the soil is improved and multiple benefits are created as much as possible.

[0052] Implementation goal: Not only the desalination of the greenhouse soil is realized, but also the wild elm money spinach is "turned waste into treasure", and the double benign circulation of ecology and economy is formed.

[0053] Specific implementation steps: S1-S5 steps are similar to example one. High value-added fruits cucumber or cherry tomato are planted in the greenhouse.

[0054] S6: The core innovation lies in the high value resource utilization of halophytes: First cutting (seedling stage): Fresh and tender wild elm money spinach seedlings are picked as special vegetables to supply the local high-end catering market, and the sales price is considerable.

[0055] Subsequent cutting (vigorous growth period): The harvested stems and leaves are ensiled or dried into hay, which is provided as feed to the sheep of the local cooperative, as shown in Table 3.

[0056] Table 3 Economic benefits of planting wild elm money spinach

[0057] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A method for continuous desalination of saline soil in a greenhouse, characterized in that, The method comprises the following steps: After the greenhouse is shaded to a light transmittance of 30-70%, the whole area inside and outside the greenhouse is irrigated once, and salt plants are planted outside the greenhouse. The irrigation amount is 50-100 m 3 / acre.

2. The method of claim 1, wherein, The method for shading the greenhouse comprises covering a shading object on the greenhouse.

3. The method of claim 2, wherein, The shading object comprises a light-transmitting non-woven fabric, a sunshade net or a cotton quilt.

4. The method of claim 1, wherein, The salt plants comprise Suaeda salsa, Salicornia, Limonium binervule, Wild Moneywort or Spinach.

5. The method of claim 1, wherein, Before the salt plants are planted outside the greenhouse, a ditch is dug, the depth of the ditch is 30-50 cm, and the width of the ditch is 30-70 cm.

6. The method of claim 1, wherein, The planting position of the salt plants comprises both sides of the ditch.

7. The method of claim 1, wherein, The planting comprises sowing or transplanting.

8. The method of claim 1, wherein, After the one-time irrigation, the conventional crops inside the greenhouse are subjected to daily irrigation management.

9. Application of the method according to any one of claims 1-8 in improving the yield of crops in saline-alkali soil.

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