Effects of municipal wastewater on soil chemical properties in cultivating turfgrass using subsurface drip irrigation

ABSTRACT

Knowing the concentrations of the nutrient elements in soils is important due to their toxic effect on humans and the environment. The aims of this study were to assess the effects of water quality, depths, and distances of lateral installation on soil chemical properties during turfgrass cultivation. A field experiment was conducted using a Split-Split-Plot design based on the randomized complete block (RCB) design with two treatments (well water and wastewater) and eight sub-treatments (45 and 60 cm distance of the laterals and 15, 20, 25, and 30 cm depths of laterals) in three replicates on a sandy loam soil, in Shahrekord, Iran. Soil samples were collected from 0 to 30 and 30 to 60 cm depth for measuring nitrate (NO₃⁻), electrical conductivity (EC), and pH at the end of the experiment. During the experiment, fecal coliform was also measured at the soil surface. Results indicated that by increasing lateral distance, NO₃⁻ level increased in both layers. With installing laterals in deeper levels, NO₃⁻ concentration decreased at the beginning, then increased in the first layer, whereas in the second layer, NO₃⁻ concentration decreased. In addition, installing laterals in deeper depth caused an increase in soil EC in the top layer, but a decrease in the lower layer. However, the results showed that there was no significant effect of the treatments (well water and wastewater) and the sub-treatments (distance and depths of laterals) on soil pH. The results also show that with increasing laterals depth, fecal coliform level decreased at the soil surface.

KEYWORDS:

• soil chemical properties
• subsurface drip irrigation
• wastewater and dripper installation depth

Acknowledgment

The authors wish to thank Shahrekord University for their general support of this project and Tarbiat Modaress University as well as Mr. Kamran Asgari and Ms. Sara Mardaninejad for their technical support.