First, technical brief
The micro-irrigation and fertilization technology of the membrane-collecting rainwater in the solar greenhouse is a method of collecting rainwater by using the water collecting effect of the membrane surface of the solar greenhouse, supporting the irrigation and fertilizing equipment, and carrying out the rain-fed agriculture for the pollution-free agriculture of the facility. The technology can effectively improve the utilization of water and fertilizer and conversion efficiency, and is an effective way to solve the water shortage in the development of solar greenhouse vegetable production in arid and semi-arid regions. It also provided technical support for the development of irrigation and agriculture and the development of greenhouse vegetable industrialization.
The core technology is to use the solar greenhouse membrane surface as the rain collecting surface, and adopt the application mode of “sunlight greenhouse membrane surface rain collecting + water raft + micro irrigation fertilization system equipmentâ€. The solar greenhouse is used for collecting water on the membrane surface, water is stored in the water, and micro-irrigation is applied in the greenhouse to form a rainwater micro-irrigation and fertilizer integration technology integrating collection (storage), micro-irrigation and fertilization. That is to say, when building a solar greenhouse in a mountain terrace, the joint design of membrane surface water collection, water raft storage and drip irrigation water supply is adopted. That is to construct a concrete sump with a depth of 20cm and a width of 40cm in the front roof of the solar greenhouse. The sump is slightly inclined toward the water raft, and the water shovel is built in the shed and at the outer end of the shed to form a shed-collecting water. Anti-seepage guide groove - water raft - the joint construction of drip irrigation. The bottom of the shed film is repaired by the collecting trough, and the rainwater flows into the greenhouse and the pool through the collecting trough. It was determined that the critical runoff rainfall of the membrane surface was 1.2 mm, and the average water collection efficiency was over 90%, which improved the current collection utilization rate of precipitation. The main technology is to dig the sump at the same time, and the collecting trough is excavated at the same time. The collecting trough is made up of 30cm wide and 15-20cm deep collecting trough with mold or brick according to 5% slope. The bottom pool is constructed in the shed. It is a rectangular shape of 4m×1m×1.5m, and an anti-seepage film is laid; the water outlet of the water tank is connected with the water sedimentation tank, and the pool is covered. The solar greenhouse in our province is generally 50m long and the membrane width is 8m. The actual membrane width after the membrane is 7m, the membrane area is 350m2, and the rainfall of 1mm can store 0.3m3. According to the annual rainfall of 400mm, the membrane is calculated for 6 months per year. 200mm, can store 60m3.
Second, technical regulations
1. Solar greenhouse construction indicators and construction standards
(1) Location of solar greenhouses. The solar greenhouse should be selected in a flat area with long sunshine hours, deep soil layers, moderate texture and convenient transportation.
(2) Greenhouse performance indicators
Insulation performance. The minimum temperature in winter should be kept above 10-12 °C, and when the outdoor temperature is extremely low at -25 °C, the minimum indoor temperature should be at least 5 °C.
Lighting performance. At noon on the sunny day before and after the winter solstice, all the inner sides of the roof can be illuminated, and the horizontal illumination at 1m height in the middle of the greenhouse reaches more than 70% of the outdoor light.
Stable performance. Can withstand the most unfavorable load combinations (including snow, wind, etc.) in the local area of ​​about 25-35kg / m2.
Soil properties. The soil is loose, deep, without salinization, and the soil is non-polluting.
(3) Structural parameters
position. The greenhouse is facing south, east to west or south to west 5°.
The length and span, and the greenhouse length should be 50m. The span is 7m.
The back height is 3.5m.
The shape and angle of the front roof, the shed is arched and the bottom angle is 60°. The waist angle is 30° and the apex angle is 13°.
Rear roof elevation and thickness. The elevation angle is 38°, the horizontal projection distance is 1.4m, and the rear roof thickness is 0.7m or more.
The height and thickness of the rear wall are 2.8m high, the wall base is 1.2m thick, and the wall back is 1m.
(4) Solar greenhouse construction
The solar greenhouse in our province is usually designed with a bamboo structure without column steel.
1 build a wall. The construction of the soil wall greenhouse should be 10cm wide on both sides of the back wall and the thickness of the gable, then the white gray line, digging 40cm deep, 1.4m wide foundation, tamping and leveling, hitting the wall with the wall, and the back wall and the gable should be built together. To avoid gaps and wind.
2 vertical steel frame. The steel frame is installed at a pitch of 3.6m, the bottom is welded by a cement base, the middle layer is welded with 16# steel in the middle, the east and west 8# wire is 11, and the 2.4m long bamboo pole is used for 0.5m between the steel frame. Each row of 7 rows, the large bamboo poles are fixed on the iron wire by wire, and the front roof and the east pull 19 lanes of 8# wire, and each row of 0.5m is tied with a row of small bamboo poles, each row of 7 rows.
3 cover the roof after the cover. Firstly, the wooden board and the upper end of the board are pressed against the spine, and the lower end is inserted into the inner side of the back wall to be no less than 15cm, and then the crop straw is compacted, the thickness is not less than 40cm, and finally the soil is pressed and a layer of grass mud is applied.
4 cover the shed film. Before the frost, choose the windless sunny day to cover the shed film. The length of the shed film should exceed 1 m above the east and west gables. The width should be 0.8 m vent and the lower end should be pressed against the collecting trough. When covering the shed film, it is best to press a laminating tape at the upper end of the shed film (so that the laminating tape does not adhere to the shed film), and the upper end of the shed film and the laminating tape are fixed together at an arch of 0.8 m from the spine. On the rod and the bamboo board, the east and west ends are rolled into the sorghum straw or the wooden strip, and the shed film is stretched at both ends and fixed on the outside of the gable.
5 After covering the shed film, the film line is pulled between the bamboo plates, the upper end is fixed on the spine, and the lower end is fixed on the ground anchor of the collector groove.
6 Cover the vent, the upper end of the vent film is pressed by the grass mud on the rear roof end, and the lower end is required to press the shed film 50cm, and the quilting is ventilated.
2. Construction of the collecting trough
(1) Use brick or concrete to build a collecting trough to collect rainwater from the front roof.
(2) The collecting trough must have a certain slope, and the end of the water trap is low and the other end is high.
(3) When constructing the collecting trough, according to the flexible length of the shed, the trench is formed at the beginning, and the trough is formed after 20 meters. As the distance from the leeches is closer, the trough is gradually deepened.
3. Construction indicators and construction standards for reservoirs and leeches
(1) Construction standards for reservoirs. A reservoir is built in the shed, designed as a rectangle of 4m × 1m × 1.5m, and an anti-seepage membrane is laid to prevent water leakage.
(2) Construction standards for mink
1 The structure of the otter. It consists of three parts: the body, the mouth and the lid.
2 excavation. Drill 0.8 meters deep under the two circles drawn. At the same time, fill the height of 0.2 m on the middle small circle and compact it. The bottom surface of the dug ring is already the junction of the hemisphere and the wellhead. The hemispherical earth mold should be made according to the size of the helium.
3 cutting soil mold: after the soil mold is cut, it should be a cylinder with a diameter of 0.5 m in the inner mold of the rake; a platform with a width of 0.5 m around the hemisphere, and the soil mold should be covered with a waste bag to avoid damage or evaporation of water. Then, excavate the soil cavity of the cylindrical part. A circular earthen groove with a depth of 4.2-5.6 meters and a width of 6 cm is drilled vertically along the edge of the hemisphere.
4 concrete pouring. It is carried out in the order of pouring the groove first, then pouring the spherical surface and then pouring the mouth. The thickness of each layer is 20cm in the tank, and the tamping is compact. Spherical pouring is carried out by smearing the concrete on the soil mold in time and tapping until it is dense. The concrete is smeared with a trowel and the concrete is applied 30 cm high for each pouring, which can be completed several times. When pouring, pay attention to the pre-buried water pipe and reserve the hole for installing the water pump.
5 backfilling. After pouring for three days, backfill the soil to the ground. Backfilling should be layered and tamped uniformly along the circle. Drain the inlet pipe when filling.
6 dug. Unearthed from the cornice, mortar is excavated when the cylindrical part reaches 1 m deep. The semi-spherical part is lined and runs from bottom to top. Use a trowel to slap the concrete on the soil wall and slap it tightly. Each layer is inclined at a height of 30 cm and gradually completed along the circumference. A space of 3 cm width is reserved at the joint of the cylindrical portion. After pouring for three days, fill the gap with “pre-shrinking mortar†and harden it, then apply the mortar.
7 lining concrete and mortar. The concrete number is 150, the cement is 425 ordinary Portland cement, the stone is the river beach gravel sieved with 4×4 cm sieve, the sand is coarse medium sand, the mud content is no more than 1%, the sand is not more than 3%, match It is selected according to the pouring part, the material dosage is 250 kg per cubic meter of cement, 1230 kg of stone, and 730 kg of sand. The semi-spherical ball in the lower part of the mouth and the lower body is to put the concrete on the soil mold. The water-cement ratio is preferably 0.65, and the water-cement ratio of the soil mold tank in the middle part of the body is preferably 0.75.
The anti-seepage part of the mortar is rubbed twice, the first time cement and sand are 1:3 in weight ratio, and the second pass is 1:2. The method is to use the steel to paste the slurry for the first time, and the wooden surface can be evenly pressed. After the second day, the concrete and the mortar are evenly mixed, and the steel paste is used to paste and calender.
8 窖 cover. It can be prefabricated and made of concrete, and can be used by special personnel. Children or abnormal people should not use it to avoid accidents.
4. The composition of the fertigation system. A complete irrigation system consists of a water source project, a first control hub, a water distribution pipeline, and a water emitter. The first control hub consists of a motor, water pump, filter, fertiliser, control and measuring equipment (pressure regulating valve, diverter valve, water meter, etc.). The water distribution pipeline consists of a pipe network, that is, a trunk pipe, a branch pipe, and a capillary pipe. A dripper or spray head mounted on a capillary.
It is mainly based on the small-scale operation of farmers and is suitable for the micro-irrigation system of greenhouse cultivation:
1 single-shed micro-irrigation and fertilization system. The control area is 0.5-2 mu, the branch pipe is laid on the ground surface, the capillary tube is laid under the plastic film, and each line of crop has a capillary tube. Use centrifugal pump or submersible pump, the supporting motor is 0.75-2.2 kW, the equipment cost per mu is 1000 yuan, and the service life is 5-7 years.
2 multi-arch sheds in turn micro-irrigation and fertilization system. Suitable for early spring crop cultivation, the shed spacing is small, mostly north-south trend. This form reduces the amount of equipment invested in the first unit. The branch pipe is laid perpendicular to the longitudinal direction of the shed on the surface, and the capillary pipes are laid in parallel in the longitudinal direction of the shed. The configuration of the first pump and motor is the same as that of a single-shed water raft, reservoir or machine well. The hose is connected to the outside of the filter, and is connected in turn to the branch pipe of the arch shed.
3 Balanced pressure centralized water supply sub-shed self-administered drip irrigation fertilization system. Suitable for large-scale vegetable concentration areas. The first water source is sufficient, the supporting power is large, and the frequency converter and other automatic control equipment can be installed to realize automatic water supply. Water valves and fertilizing equipment are installed in each greenhouse, and their respective fertilization schemes are implemented according to the varieties of planting crops.
5. Main fertilization methods and equipment required for micro-irrigation and fertilization systems
(1) Fertilization tank method. With the shunting principle, no additional power equipment is required. Suitable for greenhouse area of ​​0.5-2 acres, fertilization tank volume of about 30L, supporting pump flow 5-10m3 / hr, head 15m or so, motor power 0.75-1.5 kW. Fertilizer tanks are generally made of plastic or neutral glass reinforced plastic. The volume of the tank depends on the area of ​​fertilization, the amount of fertilizer applied per unit area, and the concentration of the solution in the tank. Calculated as follows:
Ct=Fr×A/C
Where: Ct----fertilizer tank volume (L)
Fr----the amount of fertilizer applied per unit area per fertilizer (kg/ha2)
A----fertilization area (ha2)
C----solution concentration in tank (kg/L)
(2) Venturi fertilization method. Using the jet principle, the venturi applicator is connected in parallel with the pressure regulator. Various specifications of the venturi have corresponding parameters, should pay attention to the following points when choosing to use: First, if the system flow is less than the minimum flow of the selected venturi, or the flow through the venturi exceeds its maximum flow, When vaporization occurs, select the appropriate system flow based on system flow and pressure. Second, the impact of pressure loss on the system should be considered. Control valves and pressure gauges are placed at the inlet of the system to adjust the pressure during fertilization. The third is because the venturi tube has the largest head loss caused by the system at the maximum inhalation volume. Therefore, the flow control through the venturi is slightly larger than the minimum flow rate and stabilizes the state of the fertilizer.
(3) Microgravity self-pressure fertilization method. A water storage tank is placed in the greenhouse, and the fertilizer is dissolved in an open water storage tank. After being filtered, the fertilizer liquid is dripped into the soil by the gravity of the water.
(4) Filtration equipment for fertigation systems. To prevent system blockage, the irrigation water must be purified. Commonly used are gravel filters, centrifugal filters, mesh filters and laminated filters. Gravel filters and centrifugal filters are used for primary filtration of large and medium-sized systems. The screen filter is used for final filtration when the water quality is good. When the water quality is poor, it can be used as a final filter after being connected to the gravel filter or the centrifugal filter. Generally, the filter is more than 120 mesh. Laminated filters are available for primary and final filtration and are typically available in sizes above 120 mesh.
6. Technical mode and supporting measures
(1) According to the production conditions, choose the appropriate micro-irrigation method, use the fertilizer irrigation as the core technology, at the same time, implement the mulch or biological cover surface, increase the application of organic fertilizer, determine the reasonable irrigation system and scientific fertilization program, and appropriately reduce nitrogen and increase Phosphorus, potassium supplementation, application of trace element fertilizers, in order to achieve the purpose of improving yield and quality.
(2) Under the cultivation conditions of vegetable facilities, the technology of drip irrigation under the film is mainly adopted. The soil moisture content before and after crop growth should be controlled between 60-70% and 70-90% of the field water holding capacity. :P2O5: The ratio of K2O should be controlled at 1:1:1 and 2:1:3, respectively, and the ion concentration of irrigation fertilizer is between 500-1500 mg/L.
Third, matters needing attention
The micro-irrigation and fertilization technology of membrane-collecting rainwater in the solar greenhouse is the new technology for drought-saving and water-saving agriculture in the province. The main problems that should be paid attention to during the implementation process are as follows:
First, the anti-seepage guiding trough - the water raft - the drip irrigation combined construction project should be constructed in strict accordance with the requirements of the engineering facilities, especially the guiding trough should have a certain slope to facilitate water storage;
Second, there are many types of fertigation equipment, and the design plan should be considered in accordance with its own economic conditions, greenhouse size, and irrigation quota. According to the actual situation of our province, we believe that the microgravity self-pressure fertilization method and the venturi fertilization method are more suitable for the actual irrigation and fertilization methods in our province. At the same time, according to the actual situation in our province, the setting of irrigation and filtration equipment is very necessary, and the laminated filter can be used for primary and final filtration. Drip irrigation pipes can also be selected according to actual conditions.
Third, at present, there is no fertilizer formula suitable for greenhouse fertigation in our province. Each implementing unit can formulate fertilizer formulas suitable for their respective greenhouse fertigation according to local conditions.
Source: Gansu Provincial Agriculture and Animal Husbandry
The micro-irrigation and fertilization technology of the membrane-collecting rainwater in the solar greenhouse is a method of collecting rainwater by using the water collecting effect of the membrane surface of the solar greenhouse, supporting the irrigation and fertilizing equipment, and carrying out the rain-fed agriculture for the pollution-free agriculture of the facility. The technology can effectively improve the utilization of water and fertilizer and conversion efficiency, and is an effective way to solve the water shortage in the development of solar greenhouse vegetable production in arid and semi-arid regions. It also provided technical support for the development of irrigation and agriculture and the development of greenhouse vegetable industrialization.
The core technology is to use the solar greenhouse membrane surface as the rain collecting surface, and adopt the application mode of “sunlight greenhouse membrane surface rain collecting + water raft + micro irrigation fertilization system equipmentâ€. The solar greenhouse is used for collecting water on the membrane surface, water is stored in the water, and micro-irrigation is applied in the greenhouse to form a rainwater micro-irrigation and fertilizer integration technology integrating collection (storage), micro-irrigation and fertilization. That is to say, when building a solar greenhouse in a mountain terrace, the joint design of membrane surface water collection, water raft storage and drip irrigation water supply is adopted. That is to construct a concrete sump with a depth of 20cm and a width of 40cm in the front roof of the solar greenhouse. The sump is slightly inclined toward the water raft, and the water shovel is built in the shed and at the outer end of the shed to form a shed-collecting water. Anti-seepage guide groove - water raft - the joint construction of drip irrigation. The bottom of the shed film is repaired by the collecting trough, and the rainwater flows into the greenhouse and the pool through the collecting trough. It was determined that the critical runoff rainfall of the membrane surface was 1.2 mm, and the average water collection efficiency was over 90%, which improved the current collection utilization rate of precipitation. The main technology is to dig the sump at the same time, and the collecting trough is excavated at the same time. The collecting trough is made up of 30cm wide and 15-20cm deep collecting trough with mold or brick according to 5% slope. The bottom pool is constructed in the shed. It is a rectangular shape of 4m×1m×1.5m, and an anti-seepage film is laid; the water outlet of the water tank is connected with the water sedimentation tank, and the pool is covered. The solar greenhouse in our province is generally 50m long and the membrane width is 8m. The actual membrane width after the membrane is 7m, the membrane area is 350m2, and the rainfall of 1mm can store 0.3m3. According to the annual rainfall of 400mm, the membrane is calculated for 6 months per year. 200mm, can store 60m3.
Second, technical regulations
1. Solar greenhouse construction indicators and construction standards
(1) Location of solar greenhouses. The solar greenhouse should be selected in a flat area with long sunshine hours, deep soil layers, moderate texture and convenient transportation.
(2) Greenhouse performance indicators
Insulation performance. The minimum temperature in winter should be kept above 10-12 °C, and when the outdoor temperature is extremely low at -25 °C, the minimum indoor temperature should be at least 5 °C.
Lighting performance. At noon on the sunny day before and after the winter solstice, all the inner sides of the roof can be illuminated, and the horizontal illumination at 1m height in the middle of the greenhouse reaches more than 70% of the outdoor light.
Stable performance. Can withstand the most unfavorable load combinations (including snow, wind, etc.) in the local area of ​​about 25-35kg / m2.
Soil properties. The soil is loose, deep, without salinization, and the soil is non-polluting.
(3) Structural parameters
position. The greenhouse is facing south, east to west or south to west 5°.
The length and span, and the greenhouse length should be 50m. The span is 7m.
The back height is 3.5m.
The shape and angle of the front roof, the shed is arched and the bottom angle is 60°. The waist angle is 30° and the apex angle is 13°.
Rear roof elevation and thickness. The elevation angle is 38°, the horizontal projection distance is 1.4m, and the rear roof thickness is 0.7m or more.
The height and thickness of the rear wall are 2.8m high, the wall base is 1.2m thick, and the wall back is 1m.
(4) Solar greenhouse construction
The solar greenhouse in our province is usually designed with a bamboo structure without column steel.
1 build a wall. The construction of the soil wall greenhouse should be 10cm wide on both sides of the back wall and the thickness of the gable, then the white gray line, digging 40cm deep, 1.4m wide foundation, tamping and leveling, hitting the wall with the wall, and the back wall and the gable should be built together. To avoid gaps and wind.
2 vertical steel frame. The steel frame is installed at a pitch of 3.6m, the bottom is welded by a cement base, the middle layer is welded with 16# steel in the middle, the east and west 8# wire is 11, and the 2.4m long bamboo pole is used for 0.5m between the steel frame. Each row of 7 rows, the large bamboo poles are fixed on the iron wire by wire, and the front roof and the east pull 19 lanes of 8# wire, and each row of 0.5m is tied with a row of small bamboo poles, each row of 7 rows.
3 cover the roof after the cover. Firstly, the wooden board and the upper end of the board are pressed against the spine, and the lower end is inserted into the inner side of the back wall to be no less than 15cm, and then the crop straw is compacted, the thickness is not less than 40cm, and finally the soil is pressed and a layer of grass mud is applied.
4 cover the shed film. Before the frost, choose the windless sunny day to cover the shed film. The length of the shed film should exceed 1 m above the east and west gables. The width should be 0.8 m vent and the lower end should be pressed against the collecting trough. When covering the shed film, it is best to press a laminating tape at the upper end of the shed film (so that the laminating tape does not adhere to the shed film), and the upper end of the shed film and the laminating tape are fixed together at an arch of 0.8 m from the spine. On the rod and the bamboo board, the east and west ends are rolled into the sorghum straw or the wooden strip, and the shed film is stretched at both ends and fixed on the outside of the gable.
5 After covering the shed film, the film line is pulled between the bamboo plates, the upper end is fixed on the spine, and the lower end is fixed on the ground anchor of the collector groove.
6 Cover the vent, the upper end of the vent film is pressed by the grass mud on the rear roof end, and the lower end is required to press the shed film 50cm, and the quilting is ventilated.
2. Construction of the collecting trough
(1) Use brick or concrete to build a collecting trough to collect rainwater from the front roof.
(2) The collecting trough must have a certain slope, and the end of the water trap is low and the other end is high.
(3) When constructing the collecting trough, according to the flexible length of the shed, the trench is formed at the beginning, and the trough is formed after 20 meters. As the distance from the leeches is closer, the trough is gradually deepened.
3. Construction indicators and construction standards for reservoirs and leeches
(1) Construction standards for reservoirs. A reservoir is built in the shed, designed as a rectangle of 4m × 1m × 1.5m, and an anti-seepage membrane is laid to prevent water leakage.
(2) Construction standards for mink
1 The structure of the otter. It consists of three parts: the body, the mouth and the lid.
2 excavation. Drill 0.8 meters deep under the two circles drawn. At the same time, fill the height of 0.2 m on the middle small circle and compact it. The bottom surface of the dug ring is already the junction of the hemisphere and the wellhead. The hemispherical earth mold should be made according to the size of the helium.
3 cutting soil mold: after the soil mold is cut, it should be a cylinder with a diameter of 0.5 m in the inner mold of the rake; a platform with a width of 0.5 m around the hemisphere, and the soil mold should be covered with a waste bag to avoid damage or evaporation of water. Then, excavate the soil cavity of the cylindrical part. A circular earthen groove with a depth of 4.2-5.6 meters and a width of 6 cm is drilled vertically along the edge of the hemisphere.
4 concrete pouring. It is carried out in the order of pouring the groove first, then pouring the spherical surface and then pouring the mouth. The thickness of each layer is 20cm in the tank, and the tamping is compact. Spherical pouring is carried out by smearing the concrete on the soil mold in time and tapping until it is dense. The concrete is smeared with a trowel and the concrete is applied 30 cm high for each pouring, which can be completed several times. When pouring, pay attention to the pre-buried water pipe and reserve the hole for installing the water pump.
5 backfilling. After pouring for three days, backfill the soil to the ground. Backfilling should be layered and tamped uniformly along the circle. Drain the inlet pipe when filling.
6 dug. Unearthed from the cornice, mortar is excavated when the cylindrical part reaches 1 m deep. The semi-spherical part is lined and runs from bottom to top. Use a trowel to slap the concrete on the soil wall and slap it tightly. Each layer is inclined at a height of 30 cm and gradually completed along the circumference. A space of 3 cm width is reserved at the joint of the cylindrical portion. After pouring for three days, fill the gap with “pre-shrinking mortar†and harden it, then apply the mortar.
7 lining concrete and mortar. The concrete number is 150, the cement is 425 ordinary Portland cement, the stone is the river beach gravel sieved with 4×4 cm sieve, the sand is coarse medium sand, the mud content is no more than 1%, the sand is not more than 3%, match It is selected according to the pouring part, the material dosage is 250 kg per cubic meter of cement, 1230 kg of stone, and 730 kg of sand. The semi-spherical ball in the lower part of the mouth and the lower body is to put the concrete on the soil mold. The water-cement ratio is preferably 0.65, and the water-cement ratio of the soil mold tank in the middle part of the body is preferably 0.75.
The anti-seepage part of the mortar is rubbed twice, the first time cement and sand are 1:3 in weight ratio, and the second pass is 1:2. The method is to use the steel to paste the slurry for the first time, and the wooden surface can be evenly pressed. After the second day, the concrete and the mortar are evenly mixed, and the steel paste is used to paste and calender.
8 窖 cover. It can be prefabricated and made of concrete, and can be used by special personnel. Children or abnormal people should not use it to avoid accidents.
4. The composition of the fertigation system. A complete irrigation system consists of a water source project, a first control hub, a water distribution pipeline, and a water emitter. The first control hub consists of a motor, water pump, filter, fertiliser, control and measuring equipment (pressure regulating valve, diverter valve, water meter, etc.). The water distribution pipeline consists of a pipe network, that is, a trunk pipe, a branch pipe, and a capillary pipe. A dripper or spray head mounted on a capillary.
It is mainly based on the small-scale operation of farmers and is suitable for the micro-irrigation system of greenhouse cultivation:
1 single-shed micro-irrigation and fertilization system. The control area is 0.5-2 mu, the branch pipe is laid on the ground surface, the capillary tube is laid under the plastic film, and each line of crop has a capillary tube. Use centrifugal pump or submersible pump, the supporting motor is 0.75-2.2 kW, the equipment cost per mu is 1000 yuan, and the service life is 5-7 years.
2 multi-arch sheds in turn micro-irrigation and fertilization system. Suitable for early spring crop cultivation, the shed spacing is small, mostly north-south trend. This form reduces the amount of equipment invested in the first unit. The branch pipe is laid perpendicular to the longitudinal direction of the shed on the surface, and the capillary pipes are laid in parallel in the longitudinal direction of the shed. The configuration of the first pump and motor is the same as that of a single-shed water raft, reservoir or machine well. The hose is connected to the outside of the filter, and is connected in turn to the branch pipe of the arch shed.
3 Balanced pressure centralized water supply sub-shed self-administered drip irrigation fertilization system. Suitable for large-scale vegetable concentration areas. The first water source is sufficient, the supporting power is large, and the frequency converter and other automatic control equipment can be installed to realize automatic water supply. Water valves and fertilizing equipment are installed in each greenhouse, and their respective fertilization schemes are implemented according to the varieties of planting crops.
5. Main fertilization methods and equipment required for micro-irrigation and fertilization systems
(1) Fertilization tank method. With the shunting principle, no additional power equipment is required. Suitable for greenhouse area of ​​0.5-2 acres, fertilization tank volume of about 30L, supporting pump flow 5-10m3 / hr, head 15m or so, motor power 0.75-1.5 kW. Fertilizer tanks are generally made of plastic or neutral glass reinforced plastic. The volume of the tank depends on the area of ​​fertilization, the amount of fertilizer applied per unit area, and the concentration of the solution in the tank. Calculated as follows:
Ct=Fr×A/C
Where: Ct----fertilizer tank volume (L)
Fr----the amount of fertilizer applied per unit area per fertilizer (kg/ha2)
A----fertilization area (ha2)
C----solution concentration in tank (kg/L)
(2) Venturi fertilization method. Using the jet principle, the venturi applicator is connected in parallel with the pressure regulator. Various specifications of the venturi have corresponding parameters, should pay attention to the following points when choosing to use: First, if the system flow is less than the minimum flow of the selected venturi, or the flow through the venturi exceeds its maximum flow, When vaporization occurs, select the appropriate system flow based on system flow and pressure. Second, the impact of pressure loss on the system should be considered. Control valves and pressure gauges are placed at the inlet of the system to adjust the pressure during fertilization. The third is because the venturi tube has the largest head loss caused by the system at the maximum inhalation volume. Therefore, the flow control through the venturi is slightly larger than the minimum flow rate and stabilizes the state of the fertilizer.
(3) Microgravity self-pressure fertilization method. A water storage tank is placed in the greenhouse, and the fertilizer is dissolved in an open water storage tank. After being filtered, the fertilizer liquid is dripped into the soil by the gravity of the water.
(4) Filtration equipment for fertigation systems. To prevent system blockage, the irrigation water must be purified. Commonly used are gravel filters, centrifugal filters, mesh filters and laminated filters. Gravel filters and centrifugal filters are used for primary filtration of large and medium-sized systems. The screen filter is used for final filtration when the water quality is good. When the water quality is poor, it can be used as a final filter after being connected to the gravel filter or the centrifugal filter. Generally, the filter is more than 120 mesh. Laminated filters are available for primary and final filtration and are typically available in sizes above 120 mesh.
6. Technical mode and supporting measures
(1) According to the production conditions, choose the appropriate micro-irrigation method, use the fertilizer irrigation as the core technology, at the same time, implement the mulch or biological cover surface, increase the application of organic fertilizer, determine the reasonable irrigation system and scientific fertilization program, and appropriately reduce nitrogen and increase Phosphorus, potassium supplementation, application of trace element fertilizers, in order to achieve the purpose of improving yield and quality.
(2) Under the cultivation conditions of vegetable facilities, the technology of drip irrigation under the film is mainly adopted. The soil moisture content before and after crop growth should be controlled between 60-70% and 70-90% of the field water holding capacity. :P2O5: The ratio of K2O should be controlled at 1:1:1 and 2:1:3, respectively, and the ion concentration of irrigation fertilizer is between 500-1500 mg/L.
Third, matters needing attention
The micro-irrigation and fertilization technology of membrane-collecting rainwater in the solar greenhouse is the new technology for drought-saving and water-saving agriculture in the province. The main problems that should be paid attention to during the implementation process are as follows:
First, the anti-seepage guiding trough - the water raft - the drip irrigation combined construction project should be constructed in strict accordance with the requirements of the engineering facilities, especially the guiding trough should have a certain slope to facilitate water storage;
Second, there are many types of fertigation equipment, and the design plan should be considered in accordance with its own economic conditions, greenhouse size, and irrigation quota. According to the actual situation of our province, we believe that the microgravity self-pressure fertilization method and the venturi fertilization method are more suitable for the actual irrigation and fertilization methods in our province. At the same time, according to the actual situation in our province, the setting of irrigation and filtration equipment is very necessary, and the laminated filter can be used for primary and final filtration. Drip irrigation pipes can also be selected according to actual conditions.
Third, at present, there is no fertilizer formula suitable for greenhouse fertigation in our province. Each implementing unit can formulate fertilizer formulas suitable for their respective greenhouse fertigation according to local conditions.
Source: Gansu Provincial Agriculture and Animal Husbandry
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