Study On Effect Of Reclaimed Water Irrigation On City Garden Plants And Soil

With the growth of the population and the development of the economy, the water resource was being consumed swiftly and the reuse of reclaimed water was being attached more importance by many countries. The lack of water resource in China was so serious that it has made the research and reuse of reclaimed water resource even more important than ever.This research is based on the investigation of Beijing reclaimed water current utilization situation. The whole Study is divided two parts: pot experiment(such as Pinus tabulaeformi, Pinus bungeana, Ginkgo biloba, Koelreutetia paniculata, Iris tectorum) and soil column simulated experiment that has turfgrass on it, which study the impact of irrigation on green space ecosystem with reclaimed water. The research include: the reclaimed water quality, soil physicochemical properties and plants growth. It will provide scientific data for appling of reclaimed water in large-scale garden irrigation through evaluating feasibility of reclaimed water irrigation on city green space. The conclusions reached include the following:1. The analysis result of water quality of the reclaimed water shows that: the pH value of reclaimed water is little higher than local tap water; Compared with the local tap water, nitrogen, phosphorus and potassium in reclaimed water is far higher, the nutrient content is relatively higher; Both the total dissolved solids and chloride are higher, which the sodium ion is comparatively outstanding; so it should be considered that much utilization will bring out the soil salt accumulation problem; It is not significant in the content of heavy metal between reclaimed water and tap water.2. The analysis result of pot experiment indicates that: there is no significant impact on soil pH value for reclaimed water irrigation; Comparing with tap water irrigation, reclaimed water can increase soil fertility, that available phosphorus and potassium are changed significantly, there is a little accumulated in the soil, but the increasing of organic matter and vailable nitrogen is no significantly, the two types water have the same contribution for the soil fertility; The content of total salts and chloride in soil would be increased for treatment irrigated with reclaimed water, which lead soil salt accumulation to a certain degree, but there is no impacts on the appearence of the gareden plants; The content of Cd,Cr,Zn,Ni in Pinus bungeana soil had a accumulation with reclaimed water irrigation, and they were all under heavy metal average value of our country; There is no apparently difference of mineral elememts and chlorophyll contents in leaves between the different water irrigation; The plant cell cytoplasm membrane permeation is higher and better with reclaimed water irrigation;3. The analysis result of soil column simulated experiment indicates that: pH value have increased with three types water, the pH value in loam soil present that more salt reclaimed water> reclaimed water >tap water; There is no apparently accumulation with total salts of 0～20cm soil layer with different irrigation; but there is a apparently difference with clay soil and it present that more salt reclaimed water> reclaimed water >tap water, more salt reclaimed water may cause the clay soil salinization; chloride content is much more than before after irrigation and it present more salt reclaimed water> reclaimed water >tap water, it accumulate swifter in sandy soil; The content of water-extractable sodium is lower with soil depth, and it is more than original soil with more salt reclaimed water irrigation in sandy and clay soil; After amount of irrigation, heavy metals content has increased in sandy soil and they had a more fast accumulation speed than clay and loam soil, there is no apparently effect on soil heavy metals with three types water; There is no apparently difference with turfgrass chlorophyll of clay and loam soil, but is in sandy soil; The turfgrass cell cytoplasm membrane permeation present more salt reclaimed water> reclaimed water >tap water irrigation, it shows that reclaimed water increased turfgrass resistance ability.In sum, the reclaimed water irrigation of this research district is feasible.