Environment Impact Of Irrigating Green Turf With Reclaimed Water

In this study, field experiments was conducted in the climatic conditions of Beijing. Through the establishment of artificial golf greens, use of the outdoor observation, sampling and laboratory testing methods to determine the physical and chemical properties of soil, the appearance quality of plant, mineral elements and the properties of leaching, and then, study the environment impact of irrigating Green Turf with Reclaimed Water. 18 plots were randomly assigned to three replications of two irrigation treatments and three Cultivation and managements.Irrigation resources were included Tap Water, Secondary Water, with a 120% evapotranspiration rate. managements treatment measures included Topdressing with peat and gypsum, Wetting agent, application topdressing with sand only. The main conclusions are as follows:1. Reclaimed water is secondary recycled water in this test, research of the reclaimed water quality indicated that the value of EC, total P, Ca, Mg, Na, K, Cu, Zn, total N and NH4-N are higher than tap water, but it is consistent with the"GB20922-2007, Urban Wastewater Reuse, Irrigation Water Quality of Farmland".2. Recycled water contains lots of salinity, irrigation will not affect the soil and plant in the short-term, however, if long-term irrigation, salinity accumulates in the soil, the occurrence of salinization, leading to soil compaction, reduced porosity, permeability and aeration to bring down, so, growth of plant has been affect. Grass peat has the function of water retention, permeability, soil improvement and so on, it can mitigate salt damage to plants by topdressing grass peat. After irrigation of reclaimed water, the electrical conductivity of leaching water increased significantly. When topdressing grass peat and gypsum, the soil porosity increased, accelerated leaching, the electrical conductivity of leaching water was significantly higher than the wetting agent and sand area surface.3. Suspended matter clogs the soil pores by irrigation in the reclaimed water, and leads to decrease infiltration rate of saturation soil. Topdressing wetting agent can significantly reduce soil permeability, topdressing grass peat and gypsum can mitigate the reduction of soil saturated infiltration ratio.4. Reclaimed water irrigation can reduce the pH of lawn soil, but no significant difference due to the buffering properties of the soil. After reclaimed water irrigation, the pH value of leaching water has no significant change compared with tap water.5. The content of available phosphorus and potassium are improved by reclaimed water irrigation on the lawn soil, but it is no significant difference compare with the tap water, reclaimed water irrigation does not increase the content of phosphorus and potassium in the soil rocketly. The content of total phosphorus does not make a significant increase in the lawn grass under the reclaimed water irrigation, the content of total phosphorus, total nitrogen and ammonia nitrogen in leaching water, are similar with the tap water. With the irrigation time went on, the content of total phosphorus, total nitrogen and ammonia nitrogen increases in the leaching water, shows a rising trend.6. Under the reclaimed water irrigation, the content of sodium, calcium, magnesium, potassium in the lawn soil are not significantly different compare with the tap water irrigation. Reclaimed water irrigation significantly reduces the content of Ca, Mg which is in the leaves department of lawn grass, but have no significant effect to the content of Na, K. Different topdressing stroma has no significantly impact to the mineral elements in the leaves of lawn. Contrast with tap water, reclaimed water irrigation significantly increases content of Na, K in the leaching water, but the content of Ca, Mg have no significant difference. The content of Ca, Mg which is topdressing wetting agent and sand is significantly lower than grass peat and gypsum, the content of Na, K have little change.7. Reclaimed water irrigation can increase more nutrients for plant, promote the growth of lawn grass, and increase in clipping yield dry-weight of lawn significantly, different topdressing substrates have no significant impact to clipping yield dry-weight. As the temperature changes, clipping yield dry-weight in the April and October is lower than other months throughout the year, clipping yield dry-weight reach the highest value in May, bring down a lower value in June, gradually increase after July and reach the minimum value in October.8. Reclaimed water irrigation has no significant effect on color, density, coverage and overall quality of turf in short-term, different topdressing substrates has no significantly affect on the appearance quality of lawn.Turfgrass appearance quality is poor in July because of the impact of temperature and management.