1. Characteristics of tidal irrigation There are many forms of tidal irrigation: bed type, trough type, and floor type. There are also many names: tidal irrigation, ebb and flow irrigation, and bed flood irrigation.
Tidal irrigation is a bottom irrigation method, that is, irrigation water enters from the bottom. Usually, a pump is used to fill the water storage tank into the crop cultivation bed and cultivation tank that can maintain a water depth of 1.25-5cm. Each irrigation is maintained for 6-10 minutes of soaking time. The advantages of this method are that the uniformity of irrigation is very high, the labor intensity is very low, the greenhouse space can be fully utilized, the crop leaves are not wet, and the spread of leaf diseases rarely occurs. All irrigation water is recycled, which reduces the use of fertilizers and water. cost, reducing the cost of treating irrigation discharge water. ,
Tidal irrigation is very different from micro-irrigation systems such as drip irrigation and micro-sprinkler irrigation. The water delivery system is different, and the physical movement of water in the matrix is also different, thus bringing about huge differences in production methods and results.
2. Application of tidal irrigation The tidal irrigation system mainly consists of water storage tanks, filtration and disinfection systems, water replenishment systems, heating equipment, automatic control equipment, and cultivation equipment (cultivation beds, cultivation troughs, and cultivation floors).
(1) Water storage tank Tidal irrigation requires the irrigation water to be stored in a water storage tank. Generally, 2 to 4 water storage tanks can be used in the system, and different fertilizer solutions are placed in each water storage tank, so that the fertilizer solution can be selected according to the needs of the crops. Water storage tanks can be built above ground or underground.
(2) Filtration and disinfection system In the tidal irrigation system, all water can be recycled, and wherever the irrigation water goes, there is excess water to be recycled. Each recycled irrigation water needs to be filtered and disinfected to remove matrix fibers and other impurities in the water to avoid the spread of diseases for most crops in the greenhouse.
(3) Water replenishment system Unless the water storage tank is large enough to meet the irrigation water requirements of the crop during the entire growth period, the water and nutrients absorbed by the crops must be replenished in time during irrigation. There are two ways to manage irrigation water and fertilizer concentration in the water. .
① Continuously detect the nutrient solution concentration (EC value) in the irrigation water, and add fertilizer or clean water to the water storage tank as needed.
② Use irrigation water with a fixed fertilizer concentration and regularly update all irrigation water in the system.
(4) Heating equipment In order to maintain the air content in the soil and substrate, the cultivation area must be heated when using tidal irrigation. It is usually heated at the bottom of the cultivation bed or cultivation tank.
(5) Automatic control equipment Tidal irrigation generally requires automatic control equipment. For small irrigation systems, automatic water supply equipment with irrigation timers and water storage tanks can usually be used. More advanced tidal irrigation systems can be uniformly controlled by a central computer.
(6) Cultivation equipment There are three main types of tidal irrigation cultivation equipment:
①Cultivation bed. There are two commonly used types of cultivation beds: fixed cultivation beds and mobile cultivation beds.
Fixed cultivation beds use wooden or metal frames and plastic or aluminum bottom plates. The width is generally 1.8m, the length is generally 30m, and the frame height is 5cm. There are holes in the bottom plate for better drainage.
Mobile cultivation beds are basically the same as fixed cultivation beds, but mobile cultivation beds require that the pipe connectors in the irrigation system need to have a certain degree of flexibility to accommodate the left and right movement of the cultivation bed.
②Cultivation tank. The cultivation trough is similar to the cultivation bed system, except that the bottom is no longer a flat plate, but a trench with a slight slope. During irrigation, water is flushed from the upper part of the trench and drained from the bottom. The crops flowing along the way are irrigated.
③Cultivation floor. Floor cultivation is becoming more and more popular around the world. It is applicable regardless of the scale of cultivation, and can maximize the use of greenhouse space and adapt to changes in cultivation width.
Despite the higher cost, tidal irrigation still attracts many growers because the system works well in a variety of container and bed cultivations. The uniformity of irrigation is very high, saving a lot of manpower; it has great flexibility in the selection and placement of cultivation containers, and can make full use of the greenhouse space; the crop leaves are not moist, so the spread of leaf diseases rarely occurs , reducing the use of pesticides; and, because this type of irrigation uses the principle of capillary absorption of water, container specifications in the same irrigation area can be different; in addition, the recycling of irrigation water not only reduces the cost of fertilizers and water , and means zero discharge, reducing the burden on growers to deal with discharged irrigation water.
However, there are some problems with bottom irrigation. They are fully irrigated every time and small amounts of water cannot be achieved when it is desired to slow plant growth. However, since the irrigation is sufficient and even every time, the time interval between two irrigations can be appropriately extended. For flexible irrigation, many growers also use top irrigation, such as cantilever sprinklers, sprinkler heads and other systems. Bottom irrigation also requires the substrate to have good capillary adsorption while maintaining appropriate porosity conditions. Usually, peat mixed substrates of various porosity can meet this requirement, but if the content of bark, etc. in the substrate is too high, the capillary action of the substrate will be reduced.
Post time: Jan-15-2024