First, technology introduction
The micro-irrigation and fertigation technology of solar greenhouse film surface is to use the water collection effect of the solar greenhouse membrane surface to accumulate rainwater, supplement irrigation and fertilization equipment, and to develop facilities for non-pollution agricultural dryland harvesting agriculture. The technology can effectively improve the utilization of water and fertilizer and transformation efficiency, and is an effective way to solve the water shortage in the development of solar greenhouse vegetable production in arid and semi-arid areas. It also provides technical support for the development of agricultural irrigation and the development of greenhouse vegetable industry.
The core technology is to use the solar greenhouse membrane surface as the rain collection surface, and the application mode of “the solar greenhouse membrane surface collection rain + water cellar + micro-fertigation and fertilization system equipmentâ€. The use of solar greenhouse membrane surface water collection, storage of water in the cellar, micro-fertilization in the shed to form a collection (storage), micro-irrigation, fertilization as one of the integrated technology of rain and micro-irrigation fertilization. When the mountain terraces are used to build a solar greenhouse, the conjoined design of membrane surface water collection, cellar storage, and drip irrigation water supply is adopted. That is, a concrete collecting tank with a depth of 20 cm and a width of 40 cm is built on the front roof of the greenhouse and the sink is slightly inclined toward the cellar. Two water cells are built in the shed and the outer end of the greenhouse to form a shed-water collection. Impervious guide trough - water cellar - dripping irrigation conjoined construction. At the bottom of the shed film, a gutter is built, and rainwater flows into the greenhouse and the pool through the sump. It was determined that the critical runoff rainfall on the membrane surface was 1.2 mm, and the average water collection efficiency was 90% or more, which increased the precipitation utilization rate of precipitation. The main technology is to build the shed and excavate the collecting trough at the same time. The collecting trough is made of a mold or brick with a slope of 5%. The width is 30cm, the depth is 15-20cm, and the bottom basin is built in the shed. 4m1m1.5m rectangle, and laying anti-seepage membrane; sink water outlet and cellar sedimentation tank connected to the pool capped. The length of solar greenhouse in our province is generally 50m, membrane width is 8m, actual membrane width is 7m after membrane sealing, membrane area is 350m2, 1mm rainfall can hold water 0.3m3, annual rainfall is 400mm, membrane is calculated for 6 months per year, rainfall 200mm, can store 60m3.
Second, technical regulations
1. Solar greenhouse construction indicators and construction standards
(1) Sunlight greenhouse site selection. Solar greenhouses should be selected in areas with flat terrain, long sunshine hours, deep soil, moderate texture and convenient transportation.
(2) Greenhouse Performance Index
Insulation performance. The minimum temperature in winter should be kept above 10-12°C. When there is extreme low temperature around -25°C in outdoor, the minimum indoor temperature should be maintained at least 5°C.
Lighting performance. On the sunny days around the winter solstice, all the inside of the roof can be illuminated, and the horizontal illuminance at a height of 1m in the middle of the greenhouse reaches more than 70% of the outdoor illumination.
Solid performance. Can withstand the most unfavorable local load combination (including snow, wind, etc.) about 25-35kg/m2.
Soil properties. The soil is loose, deep and salt-free, and the soil is free from pollution.
(3) Structure parameters
position. The greenhouses face south, east-west or south-west-5.
Length and span, greenhouse length is 50m. Span 7m.
Back height 3.5m.
The shape and angle of the front roof, the arch is round and the bottom corner is 60. Waist angle 30, top angle 13.
After the roof elevation and thickness. Elevation angle 38, horizontal projection distance 1.4m, back roof thickness 0.7m or more.
The height and thickness of the back wall are 2.8m high, the wall thickness is 1.2m, and the back of the wall is 1m.
(4) Solar greenhouse construction
The solar greenhouse in our province usually adopts the design of column-free steel bamboo structure.
1 building a wall. The construction of soil wall greenhouses should be relaxed by 10cm on both sides of the back wall and the thickness of the gable, and then sprinkle the white-grey line, dig 40cm deep, 1.4m wide foundation, leveling, hitting the wall, back wall and gable to be linked together To avoid air leakage.
2 standing steel frame. The steel frame is installed at a spacing of 3.6m. The bottom is welded by a cement base. The middle layer of the rear layer is welded with 16# steel bars, and 11 # of 8# iron wires are drawn from the east and west, and each 0.5m of 2.4m long bamboo rods are used between the steel frames. Each row of 7 rows, large bamboo poles are fixed on the wire with a wire, the front roof pulls 19 # 8 iron wires, and every 0.5m is tied with a row of small bamboo poles, each row of 7 rows.
3 cover the roof. The first plank, the upper end of the plank pressing down the spine, the lower end of the rear wall inserted not less than 15cm, and then filled with crop straw compaction, thickness not less than 40cm, and finally pressure soil, wiping a layer of grass mud.
4 cover the film. Before the frost, choose no wind to cover the film. The length of the film should be more than 1 meter from the east-west gable. The width should be 0.8 meters above the ceiling and the lower end should be pressed against the sump. When covering the film, it is better to press a film into the top of the film with an embossing method (so that the film does not adhere to the film). The upper end of the film and the film tape are fixed to the arch 0.8 m away from the ridge beam. On the poles and bamboo boards, the eastern and western ends are caught in sorghum stalks or wood strips, and the shed film is stretched at both ends and fixed on the outside of the gables.
5 After the film is covered, a laminating line is pulled between the bamboo plates, the upper end is fixed on the ridge beam, and the lower end is fixed on the anchor of the collecting tank embedded part.
6 Cover the vents. The upper end of the vent membrane shall be pressed on the top of the rear roof through grass mud, and the lower end shall be pressed against the shed membrane 50 cm, and the vents shall be ventilated.
2, the construction of the collector
(1) Use brick or concrete to build a gutter to collect front rainwater.
(2) The collecting trough should have a certain slope, one end of the cellar is low, and the other is high.
(3) When constructing the header tank, according to the captain's flexibility, the trench shape was just completed. After 20 meters, the trench was built. As the distance from the cellar gets closer, the tank gradually deepens.
3. Construction indicators and construction standards for reservoirs and water cellars
(1) The construction standard of the reservoir. The reservoir was built in a shed, designed as a rectangle of 4m1m1.5m in size, and an impermeable membrane was laid to prevent water leakage.
(2) Construction standards for water cellars
1 The structure of the water cellar. It is composed of three parts: the cellar body, the cellar mouth and the cellar cover.
2 excavation. Dig 0.8 m deep vertically between the two painted circles. At the same time fill in the middle circle 0.2 meters high and compact. The underside of the dug hole has been the joint between the hemisphere and the wellhead. Hemispherical soil mold should be based on the size of the cast cellar.
3 Soil cutting mold: After the soil mold is cut, it should become a 0.5 m cylinder with a diameter of 0.5 m in the mouth of the pit; the hemisphere is surrounded by a platform with a width of 0.5 m. The soil mold to be shaved is covered with a waste bag to avoid crashing or moisture evaporation. , Then excavate the earth mold groove of the cylindrical part of the pit body. Cut down the edge of the hemisphere to a depth of 4.2-5.6 meters and a width of 6 centimeters.
4 concrete pouring. According to the order of pouring the first slot, then pouring the ball face and then pouring the pit. The thickness of each layer poured in the tank is 20cm, compacted and solidified. Spherical pouring with the wipe to the concrete affixed to the soil mold in a timely manner until the tap, cast in the pit with a trowel affixed to the concrete each casting height of 30cm, can be divided into several completed. When pouring, pay attention to the buried water inlet pipe and reserve the hole for installing the water pump.
5 backfilled and solidified. Three days after pouring, the soil is filled back to the ground. Backfilling should be layered and compacted and uniformly increased along the circle. Fill the inlet pipe when filling.
6 dig pits. Unearthed from the pit, mortar excavation is required when the cylindrical portion is up to 1 meter deep. The semi-spherical ball is partially lining and is carried out from the bottom up. Using a trowel, the concrete posts were tapped and compacted on the soil wall. The height of each layer was 30 cm, gradually completed along the circumference, and a gap of 3 cm wide was reserved at the junction of the cylindrical parts. Three days after pouring, the gap was filled with “pre-shrink mortar†and hardened, followed by mortar.
7 Lining concrete and mortar. Concrete No. 150 is used for concrete marking, cement is 425 ordinary portland cement, stone is river beach gravel sieved with 44 cm sieve, sand is coarse sand, clay content is less than 1%, sand is no more than 3%, and mix ratio is Casting site selection, material consumption 250 kg per cubic meter of cement, stones 1 230 kg, 730 kg of sand. The semi-circular ball in the bottom of the pit and in the pit is to put the concrete on the soil mold. The water-cement ratio is 0.65, and the water-cement ratio of the soil tank in the middle of the pit is 0.75.
Impervious site mortar plaster two times, the first time cement, sand in a weight ratio of 1:3, the second time 1:2. The method is to use a steel spatula for the first time. The wood wool can evenly compress the hair surface. After the second day, the concrete and mortar are mixed evenly. The steel slurry is applied and pressured.
8 cellar cover. Can be prefabricated concrete and wooden, special management and use, children or non-normal people do not open to use, so as to avoid accidents.
4, the composition of the fertigation system. A complete set of irrigation system consists of water source engineering, the first control hub, transmission and distribution pipelines, and emitters. The first control hub consists of motors, pumps, filters, fertilisers, control and measuring equipment (pressure regulators, diverter valves, water meters, etc.). Transmission and distribution pipelines consist of pipe networks, namely trunk pipes, branch pipes and capillary tubes. The dripper or sprinkler mounted on the capillary.
With the small-scale operation of farmers, the micro-irrigation fertilization system is suitable for greenhouse cultivation:
1 Single shed microfertigation system. The control area is 0.5-2 mu, branch pipes are laid on the surface, and the capillary tube is laid under the mulch with one capillary tube in each row. The use of centrifugal pumps or submersible pumps, supporting motor 0.75-2.2 kilowatts, equipment costs 1,000 yuan per acre, the useful life of 5-7 years.
2 multi-arc rotating fertilization system. Suitable for early spring crop cultivation, small shed spacing, mostly north-south direction. This form can reduce the first equipment investment. The branch pipes are laid vertically on the surface of the shed, and the capillary pipes are laid parallel to the shed in the longitudinal direction. The configuration of the first pump and motor is the same as that for a micro-irrigation system such as a single-cell water cellar, a reservoir, or a well. The outer side of the filter is connected to the hose, which in turn is connected in turn to the branch pipe of the arch shed.
3 Hengshui centralized water supply subdivision self-management drip irrigation fertilization system. Suitable for large-scale vegetable planting areas. The first water source is abundant and the supporting power is large. The frequency conversion governor and other automatic control equipments can be installed to achieve automatic water supply. Each greenhouse is equipped with water valves and fertilizing equipment, and each fertilization scheme is implemented according to the crop varieties.
5. Main fertilization methods and equipment required for the micro-irrigation fertilization system
(1) Fertilizing pot method. Using the principle of shunting, no additional power equipment is required. Suitable for greenhouse area of ​​0.5-2 acres, fertilization tank volume of about 30L, matching pump flow 5-10m3/hr, head of about 15m, motor power 0.75-1.5 kilowatts. Fertilizer tanks are generally made of plastic or neutral glass steel. The volume of the tank depends on the fertilization area, the amount of fertilizer applied per unit area and the concentration of the solution in the tank. Calculated as follows:
Ct=FrA/C
Where: Ct ---- Fertilizer tank volume (L)
Fr---- Fertilizer amount per unit area per application (kg/ha2)
A----fertilizing area (ha2)
C----Concentration in the tank (kg/L)
(2) Venturi device fertilization method. Using the principle of jet flow, the Venturi fertilizer applicator is connected in parallel with the pressure regulator valve. Various specifications of the Venturi device have corresponding parameters. When choosing to use, the following points should be noted: First, if the system flow is less than the minimum flow rate of the selected Venturi tube, or the flow rate of the Venturi tube exceeds its maximum flow rate, When vaporization occurs, select the appropriate system flow based on system flow and pressure. The second is to consider the impact of pressure loss caused by the system. Control valves and pressure gauges are installed at the inlet of the system to adjust the pressure during fertilization. Third, due to the maximum head loss caused by the system when the Venturi tube is maximally inhaled, the flow rate through the Venturi tube is controlled to be slightly larger than the minimum flow rate, and the suction state is stabilized.
(3) Microgravity self-pressure fertilization. Raise a storage tank in the greenhouse, put the fertilizer into an open water storage tank and dissolve it. After the fertilizer solution is filtered, the gravity of the water drops into the soil.
(4) Filtration equipment for irrigation fertilization systems. To prevent system blockage, irrigation water must be purified. Commonly used are gravel filters, centrifugal filters, screen 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 the final filtration when the water quality is good. When the water quality is bad, it can be used as the last filter after the sand filter or the centrifugal filter. Generally, the 120 mesh or more specification is selected. Laminated filters can be used for both primary and final filtration, and are generally available in sizes above 120 mesh.
6. Technical mode and supporting measures
(1) According to the production conditions, choose the appropriate micro-irrigation method, and add fertilizer as the core technology. At the same time, implement the mulch or bio-covered surface, increase the organic fertilizer, determine the rational irrigation system and scientific fertilization program, and appropriately reduce nitrogen and nitrogen. Phosphorus, potassium, trace element fertilizer, in order to achieve the purpose of improving production and quality.
(2) Under the conditions of vegetable facility cultivation, mainly adopting the techniques of drip fertigation under the film, the soil moisture content of the crop before and after the growth should be controlled between 60-70% and 70-90% of the field water holding capacity. : P2O5: K2O ratio should be controlled around 1:1:1 and 2:1:3 respectively, and the ion concentration of irrigation fertilizer solution should be between 500-1500 mg/L.
Third, pay attention to matters
Rainfall micro-irrigation fertilization technology for solar greenhouse membrane surface as the new technology for dryland and water-saving agriculture newly promoted in our province, the main issues that should be noted in the implementation process:
First, the anti-seepage guide trough - water cellar - drip irrigation joint construction projects should be constructed in strict accordance with the requirements of the engineering facilities, in particular guide trough should have a certain slope, in order to facilitate the impoundment;
Second, there are many types of irrigation and fertilization equipment, which should be designed in consideration of their own economic conditions, greenhouse size, and irrigation quotas. According to the reality of our province, we believe that the micro-gravity 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 of our province, it is necessary to set up the irrigation filter equipment. The laminated filter can be used for primary and final filtration. Drip irrigation pipes can also be selected based on actual conditions.
Third, at present, there is no fertilizer formula suitable for greenhouse fertigation in our province. Each implementation unit can formulate fertilizer formulas suitable for their actual greenhouse irrigation and fertilization according to actual conditions in different regions.
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