Soil nitrate transport in subsurface drip irrigation with different lateral spacing under turfgrass culture using municipal wastewater

The main objective of this study was determination of the effects of water quality, installation depth and space of subsurface drip irrigation (SDI) laterals on soil nitrate under turfgrass culture at the experimental farm of the Shahrekord University, Shahrekord, Iran. Split Split Plot was employed as the experimental design with experimental arrangement of completely randomized block design including 16 treatments and three replications. Treatments included two types of water quality: fresh water (W) and treated wastewater (WW), two installation spacing of SDI laterals (45 and 60 cm) and four depths of placement of SDI dripper (15, 20, 25 and 30 cm). Soil samples were collected from two layers (0-30 and 30-60 cm) and analyzed for No3- at the end of the experiment. The ANOVA results show that interaction of irrigation water quality × lateral spacing × installation depth of SDI laterals was significant on No3- concentration in the layers. The results indicated that irrigation with the wastewater as compared to fresh water causes higher No3- concentration. The No3- concentration in the first and second layers increased by increasing lateral spacing. Also in the first layer, by increasing of lateral depth No3- concentration decreased at first, then increased, whereas in the second layer with increasing lateral depth, decreased.