Water And Salt Transport In Dredger Fill Under Steady Flow And Its Adaptability To Plant Growth

At present, directly using dredger fill for ecological construction in the reclamation area is a hot issue at home and abroad. This thesis study the law of water and salt movement through laboratory experiments, and verify that plants can grow on the desalinated dredger fill through pot experiments. The results of this research can provide theoretical support and technical guidance of ecological construction in using dredger fill directly in Caofeidian and coastal areas. The mainly results are as follows:Under the 1cm and 3cm water pressure, the process of leaching desalination can be divided into 3 stages, including desalination of top-soil, moving down of salt peak and desalination of Sub-soil. The amount of water during desalination is 760～1 150 mm(1cm) and 740～1 130mm(3cm), and the time-consuming is 113h(1cm) and 89h(3cm). During the process of desalination, dredger fill changes from NaCl-type to Ca(HCO₃)₂-type and CaSO4-type, and content of ion in desalinated dredger fill haven't toxic effects to general plant. The value of pH, SAR and RSC of filtrate and soil is within the scope of that general landscape plants can withstand.When groundwater table is 50cm(Z1) and 100cm(Z2), the soil columns need 15 and 51 days to the final of test, and the amount of groundwater consumed is 8 905 ml and 12 515 ml. The total consumption of groundwater of Z1 and Z2 changes linearly with time. At the surface of Z1 and at the depth of 5cm of Z2 appear salt crust, and the average water content of Z1 and Z2 is 18.8% and 20.1%, and the average salt content is 0.5% and 0.4%. The law of salinity change is similar to the change of electrical conductiv of soil solution. During the process of returning salt, the transfer speed of cation and anion is Na⁺>Ca²⁺>Mg²⁺ and Cl^->HCO₃^-≈SO₄^2-. And there is no alkalization phenomenon.Increasing the using of manure is little effect to add the color of tall fescue. The texture of tall fescue with no fertilizer is worse than comparison, but growing of tall fescue is gradually increasing at late stage, while the scores of texture is low overally.The turf density of tall fescue is increased with the increase of fertilizer when using manure alone or sludge, but when the content of sludge 10% and above, little fertilizer can improve turf density. Overall appearance point of view, uniformity of tall fescue is similar at different fertilization modes.The difference of chlorophyll is very significant in different treatments. Chlorophyll content of white clover increase with the increase of fertilizer applied, but when exerted mixed fertilizer, chlorophyll content of tall fescue has trend to decrease. Chlorophyll a/b in fertility and not fertilization is in a range which is approaching to comparison. White clover has a least membrane permeability in C100%, and maximum membrane permeability is in C94%+W5%+N1%. While least membrane permeability of tall fescue is in C90%+W10%, maximum membrane permeability is in L100%.The amount of plant biomass increase with the increase of fertilizer, using manure can increased aboveground biomass of white clover significantly, but sludge fertilizer is better on tall fescue.