Effects Of Irrigation On Green Space Ecosystem With Reclaimed Water

This study is supported by 863 Program "water saving irrigation technique system and demonstration in urban green space of semi-arid North of China" (2002AA2Z428111) and "Research of water supply technology and Environment Security in Olympic Park of Beijing". The whole Study is divided two parts: pot experiment and fields research, which study the impact of irrigation on green space ecosystem with reclaimed water. It will provide scientific data for constituting "Standards for Reclaimed Water Quality on Landscape Irrigation" through evaluating feasibility of reclaimed water irrigation on green space. The conclusions reached include the following:1. the research of water quality, soil, plants indicates that salinity, chloride, bicarbonate, boron and heavy metals will bring negative impact to soil and plants. Nutrients in reclaimed water have active effect on plant growth, but sometimes deteriorate water quality and contaminate groundwater. These water parameters should be monitored frequently.2. In pot experiment, at the same research conditions, 11 plants are irrigated by secondary treated water, tertiary treated water and tap water, the result indicates that secondary treated water has active effect on plant growth, tertiary treated water by reverse osmosis(RO) process has least effect on plant growth, other tertiary water of microfiltration(MF), ultrafiltration(UF) and bio-carbon have the similar influence on soil and plants. Nutrients in different water is the main impact factor. Although salinity, sodium, chloride in soils irrigated by reclaimed water increase variously, they don't harm to soil property and plant growth.3. Electric conductivity(.EC), Sodium Adsorption Ratio (SAR), sodium, chloride, bicarbonate and sulphate increase variously in soils irrigated by treated water, the extent of variation is influenced by water quality and irrigation time. Based on the field research, the article calculated the linear equation of Soil Salinity and EC in costal saline area.4. In soils with reclaimed water irrigation, data about nutrient indicated that irrigation with reclaimed water increases available nutrients , but total nitrogen in soils has not obvious increase, sometimes declined. The content of nitrogen, phosphorus and potassium in leaves of plants irrigated by different water hasn't significantly different.5. In reclaimed water for irrigating green space, content of heavy metals(Cu, Cd, Pb, Cr,Zn, Hg,As) are accord with "Standards for Irrigation Water Quality"(GB5084-92), content of heavy metals in soils are in the range of " Standards of Soil Environmental Quality"(GB15618-1995),so their impact on soil and plants is notnotable.6. In soils with long irrigation of reclaimed water, most parameters in three layers have not significant different, salt, nitrate-N are prone to move downward, which can lessen harm to soil and plants, but is likely to contaminate groundwater.7. Rose, Japanese Pagodatree, Evergreen Euonymus, willow, white clover and Tall fescue in researched plants have better endurance, which are suitable for reclaimed water irrigation. The resistance of chinar, hawthorn and ural falses piraea are relatively low, which maybe bring problems. The suitability of plants is related to salt-tolerance of themselves.8. Summing up pot experiment and fields research , we set up "Standards for Reclaimed Water Quality on Landscape Irrigation"...