The Experimental Study On Laws Of Seepage With Zippered Plastic Pipe Andpercolaction Irrigation Inside The Shelf

This task is an important part of a major technical item undertaken by Science Commission in Harbin city which centered around the applied research on the technique of percolation irrigation with zippered plastic buried pipe. This thesis aims at promoting the innovation on irrigation methods and the development of irrigation techniques in vegetable cultivation, and also provides for percolation irrigation by way of experimental study on the seepage flow both in air and soil with zippered plastic pipes and on the application of percolation with zippered plastic pipes to vegetable tomato cultivation in shelves.Percolation irrigation takes way of underground micro-irrigation which worked with the aid of micro pore pipes for percolation that is buried at root zone. And the crops' demand for water can be met by percolating through the soil on the condition of low pressure at the right time with right volume. It is one of the best water-saving irrigation methods that can save water in the highest degree for such advantages as saving water, saving energy, increasing production, raising air temperature and ground temperature inside the shelf, lowering air humidity inside the shelf, decreasing plight and reducing the use of pesticide and chemical fertilizer, etc. But percolation irrigation is far from a ripe irrigation method for the problems existing in the development of pipes for PI and the two difficult problems which hamper the development of PI(one is the low uniformity degree irrigation, the other is the blockage in percolation irrigation pipes). In view of the above problems, zippered plastic pipes which have obtained patent was adopted as PI pipe in the providing theoretical basis and data support for the application of zippered PI pipes to the vegetable cultivation in shelves.This thesis, firstly, made an experimental study on the seepage flow both in air and oil with zippered plastic pipes. The special structure of zippered plastic pipe zippered seep holes made a greater seepage quantity on the condition of bare pipe (no anti-blocking material adopted at the mouth of seep holes ).so several kinds of anti-seepage material were adopted in the experiment of this part in order to find the proper anti-seepage material (nonwoven fabrics glued by neoprene) and working head (3m's working herd on initial irrigation).In the second part of the thesis, an experimental study on the effect of embedded depth on the uniformity coefficient of irrigation and the distribution of soil moisture was made. There are three treatments in the experiment this part, the embedded depth being 25cm(A treatment), 35cm(B treatment)and 45cm(C treatment) respectively. After the observation and analysis on the uniformity coefficient of irrigation and the distribution of soil moisture under each different treatment, a result was got that 35cnrs embedded depth is comparatively appropriate for vegetable cultivation for the high uniformity coefficient and the vegetable cultivation for the high uniformity coefficient and the concentrated distribution of irrigation water in the main root zone. In the third part, a comprehensive check experiment was made on percolation irrigation andfurrow irrigation: the percolation irrigation is superior to the furrow irrigation for such advantages as saving water, saving energy, increasing production, raising air temperature and ground temperature inside the shelf, lowering air humidity inside the shelf and reducing plights, and ect.The fourth part is an experimental study on the anti-blocking performance of zippered plastic pipes. Negative pressure blockage and biological blockage are two main forms of blockage for the special structure of zippered plastic pipes, so two treatments were made here:(i) nonwoven fabrics glued by neoprene and(ii) nonwoven fabrics glued by neoprene with a layer of asphalt emulsion applied outside. The result is that nonwoven fabrics glued by neoprene is more effective in anti-blockage, and zippered plastic pipes are superior in blockage-proof performance.The end prod...