Irrigation and fertilization in one go - a detailed introduction to greenhouse topdressing and irrigation technology

I. Facility Construction

The facilities consist of three parts: a water tank, a water delivery pipe, and subsurface irrigation laterals. The water tank is located inside the middle of the back wall of the greenhouse. It is built with bricks and cement, forming a rectangular tank 2 meters long, 1 meter wide, and 1.2 meters high. The bottom is 0.2 meters above the ground. Two iron pipes, each approximately 0.3 meters long, are built into the sides 0.1 meters above the bottom of the tank. The outer diameter of the iron pipes connects to the valves and plastic pipes. The length of the plastic pipes equals the length of the greenhouse and is buried beneath the north end. Laterals are connected to the plastic pipes; the distance between the laterals is consistent with the ridge distance, and the length of the laterals equals the length of the ridges. The tops of the plastic pipes and laterals are sealed. There are several water seepage holes on the laterals, ideally spaced 1 meter apart. The laterals are buried under the ridges, where the crops are planted. The water tank is usually kept full of water. When irrigation is needed, open the valve, and the water in the tank flows through the plastic pipes into the laterals, then through the seepage holes in the laterals into the soil at the roots of the crops. If fertilizer is needed, the fertilizer can be dissolved in the water tank before being directed to the soil at the roots of the crops through the pipes, thereby achieving fertilizer application.

II. Advantages of Subsurface Irrigation and Fertilization
1. Time and labor-saving. Irrigation and fertilization can be completed simply by opening the valve.
2. Water-saving. Subsurface irrigation requires only 2-3 cubic meters of water per mu each time, saving 3/4 of the water compared to furrow and flood irrigation.
3. Fertilizer-saving. Deep subsurface fertilization saves 1/3-1/4 of the fertilizer each time and achieves uniform fertilization.
4. Disease reduction. The humidity in the greenhouse is significantly reduced, leading to fewer diseases and less pesticide pollution.
5. Beneficial for increasing soil temperature. The water in the water tank is stored until its temperature is close to the indoor temperature before irrigation, minimizing the decrease in soil temperature.
6. Improved soil properties. It prevents soil compaction, keeping the topsoil loose and well-aerated, promoting crop root development and growth.
7. Low cost. The one-time investment for the pipes is 600 yuan per mu, with a usable lifespan of 8-10 years.

 III. Precautions for Use
1. The water tank should be located in the middle of the greenhouse. If the greenhouse is 80-100 meters long, two water tanks should be installed, with equal water delivery distances. The diameter of the water outlet pipe of the water tank should be 50 mm.
2. Each mu of greenhouse should have a water tank with a capacity of 3-4 cubic meters.
3. Keep the water tank clean. Cover the water tank with a plastic sheet, and wrap the outlet pipe with double-layered gauze to prevent debris from entering the laterals and blocking the seepage holes.
4. Before tilling the land, remove the laterals. Rebury them after tilling. Remove any blockages from the seepage holes each time they are removed.
5. Regularly clean the gauze filter on the outlet pipe to prevent dirt from entering the pipes. Typically, clean it once before each water storage.