water balance assessment of different substrates on potash tailings piles using nonweighable lysimeters water balance is an important tool to evaluate water deficit or excess in crop systems however few studies have evaluated the water balance of vegetation grown on the residues from potash mining because the high sodium chloride levels of the residues hinder agricultural development therefore this study aims to measure the water balance components in eight nonweighing lysimeters installed on a potash tailings pile in heringen werra germany these lysimeters were filled with different mixtures of household waste incineration slags and coal combustion residues resulting in 4 different substrates with two repetitions manual seeding was performed using 65 perennial ryegrass lolium perenne l 25 red fescue festuca rubra l and 10 kentucky bluegrass poa pratensis l environmental conditions were monitored using an automatic weather station groundlevel and 1mhigh rain gauges precipitation and drainage were recorded weekly following the initial saturation of the lysimeters water balance components were determined for two hydrological years based on the expression et mm p d where et evapotranspiration p precipitation and d drainage in addition evapotranspiration was studied using the standard fao penmanmonteith equation and haudes method the lysimeter water balance measured in 2014 revealed an actual evapotranspiration rate of 664 for substrate 1 669 for substrate 2 651 for substrate 3 and 641 for substrate 4 in 2015 evapotranspiration ranged from 657 for substrate 4 to 702 for substrate 1 we observed that the fao penmanmonteith and haudes evapotranspiration models generally overestimated the water use of the green coverage by 67 and 23 respectively our study suggests that an evapotranspiration cover for potash tailings piles may decrease brine drainage from these piles and reduce soil and water contamination