Changes in soil properties of an eastern Australian vertisol irrigated with treated sewage effluent following gypsum application

Abstract

Historically many towns in inland Australia disposed of their treated sewage by pumping into local rivers. This is no longer a feasible proposition. Alternatives to river pumping include irrigation and/or aquaculture. As treated sewage effluent may contain large amounts of nitrogen, phosphorus and sodium salts, if not managed carefully, soil salinity, sodicity and nutrient accumulation could increase. The objective of this study was to evaluate if gypsum application had any effect on soil-quality changes in a Vertisol due to irrigating a cotton-wheat rotation with tertiary treated sewage effluent. The treatments were application of 2Á5 t ha À1 of gypsum in June 2000 before commencing irrigation and an untreated control. Annually, between June 2000 and April 2004, irrigation water quality and soil changes in nitrate-N, EC 1:5 , pH, organic carbon, Cl, dispersion index, and exchangeable cations to a depth of 1Á8 m were measured and deep drainage inferred with the chloride mass balance method. Cotton lint yield and fibre characteristics were also evaluated.Irrigation with treated sewage effluent increased exchangeable Na in all depths, and exchangeable Ca and K in the clayey-textured surface 0Á6 m, but decreased exchangeable Ca and K, and SOC in the coarser clay-loam-textured depths > 0Á6 m. Nitrate-N leaching, associated with deep drainage had occurred, as the crops had not used all the N in irrigation water. Gypsum application decreased exchangeable Ca, increased dispersion and during the 2003-2004 season deep drainage, but had no effect on salinity, sodicity or pH. Application of commercial gypsum at sub-optimal rates with sodiumrich irrigation water is, therefore, unlikely to improve soil properties. Stubble incorporation before sowing cotton in 2003 appears to have mobilized gypsum applied during 2000. Gypsum application reduced cotton lint yield and fibre quality during

Review: Use of recycled wastewater for irrigating grapevines

“…1994). Interestingly, in a Vertisol soil irrigated with municipal wastewater, Hulugalle et al. (2006) reported a reduction in exchangeable Ca 2+ and increased clay dispersion under gypsum application.…”

Effects of treated wastewater irrigation on soil salinity and sodicity in Sfax (Tunisia): A case study

“…Research dealing with the environmental impacts of wastewater applications has mostly focused on short-term effects on plant growth and has usually been conducted in experimental plots in open fields HERPIN et al, 2007;HULUGALLE et al, 2006). Studies examining indirect effects of various TWE qualities (CHOUDHARY et al, 2006;MINHAS et al, 2007;TEDESCHI and DELL' AQUILA, 2005; VAN HOORN et al, 2001) are also generally based on short-term laboratory experiments, sometime using continuous water flow in packed soil columns (JALALI et al, 2008;SUAREZ et al, 2006).…”

“…Most of the salts added are only partially removed during conventional sewage treatment (secondary and tertiary), so they remain in the irrigation water (TARCHITZKY et al, 1999). Previous studies related to the changes in soil salinity and sodicity after irrigation with wastewater are mostly based on short-term laboratory experiments with continuous water flow in packed soil columns (JALALI et al, 2008) or on controlled field experiments conducted in small plots HERPIN et al 2007;HULUGALLE et al, 2006). However, little is known about the time needed for soil salinization to appear in real agricultural conditions.…”

Some characteristics of organic soils irrigated with municipal wastewater

“…Soil irrigation with wastewater (WW) is a problem dating back to ancient times (Filip et al ., 1999; Hoffmann et al ., 2002; Hulugalle et al ., 2006; Levy, in press). Globally, around 20 million ha of land are irrigated with WW.…”