1. Most of the water supply for drip irrigation under membrane and drip irrigation in greenhouses is well water, but the pump of well water directly supplies drip irrigation in greenhouses. There is a contradiction between simultaneous water supply and different types of vegetables.Therefore, greenhouses drip irrigation water supply should generally choose the following forms:
(1) pressure irrigation and water supply.For the area with many and centralized greenhouses, pressure tanks are generally used for centralized pressure. Pressure tanks are installed between the water pump and drip irrigation to ensure the continuous work of the pipe network under unmanned control. No additional pressure equipment is set in the greenhouses.The water source is provided with a filtration facility composed of a rotary flow sand separator and a screen filter.Pressure tank water supply one-time investment is small, convenient management, the disadvantage is to increase the cost of irrigation operation.
(2) building water towers to supply water.In the regional center where greenhouses are concentrated, a water tower for drip irrigation of each greenhouse is constructed to meet the pressure and unstable water needed for drip irrigation of greenhouses.Install strainer on the water pipe of pump and water tower, etc.The one-time investment of water tower construction is large, but the operation cost is low, and it can also play a role in regulating the water storage.
(3) single shed small pump water supply.For each greenhouse, 5-7 cubic meters of buried storage tank shall be built nearby the greenhouse, and the water supply to the pool shall be centralized by machine Wells. Micro-pump shall be installed in a single shed to pressurize drip irrigation, and filters shall be installed in the first part of drip irrigation.In terms of overall calculation, the investment is relatively large, but it is easy to build and manage each greenhouse.
2. Application of submembrane drip irrigation
(1) selection of capillary tubes for drip irrigation.It is very sensitive to the supply of water and nutrients. It requires a large density of drip head arrangement and a large amount of capillary. Therefore, the capillary selection of drip irrigation belt with lower price can effectively reduce the cost of drip irrigation, and it is reliable in operation and convenient in installation and use.
(2) arrangement of submembrane drip irrigation.Before drip irrigation into the shed, the ridge should be crossed (or the length of the shed), the width of the ridge is 40 cm, and the height is 10-15 cm, so as to make double high rows with low center. Drip irrigation belt should be placed in the low concave place in the middle of double high rows, and the ridge should be covered with plastic film.The center distance of double high ridges is generally 1 meter, so the spacing of capillary tubes in drip irrigation is 1 meter.The length of each capillary of drip irrigation is generally equal to the width (or length) of the shed, and two rows are sometimes arranged for vegetables with large water demand.Branch pipes are generally arranged along the back wall of the shed (or along the span of the shed) and the length of the shed (or the span of the shed) is equal.The first part of the branch pipe is equipped with a fertilization device and a two-stage mesh filter.
(3) the benefits of vegetable drip irrigation.Drip irrigation under greenhouse film generally saves about 70% more water than flood irrigation, and can greatly reduce the humidity in the greenhouse, reduce diseases and insect pests, and improve the quality of vegetables.Compared with the flood irrigation shed high temperature, fresh vegetables can be on the market half a month in advance.Drip irrigation of vegetables under greenhouse film can increase production by 20%-40%, and the payback period of investment is generally 4-6 months.
3. Management of submembrane drip irrigation
(1) standardize operation.In order to achieve the best effect of vegetable drip irrigation, the design, installation and management must be standardized, and filtering facilities can not be removed at will and holes can not be drilled at any location.
(2) pay attention to filtering.Drip irrigation vegetables under greenhouse film, to often clean the filter inside the network, found that the filter damage to be replaced, drip irrigation pipe network found sediment should be opened in time to wash the plug.
(3) proper irrigation.The duration of drip irrigation should be controlled within 1-4 hours according to the degree of water shortage and the variety of vegetables.