Soil water storage, drainage, and leaching in four irrigated cotton-based cropping systems sown in a Vertosol with subsoil sodicity

Abstract

Comparative studies of drainage and leaching in irrigated cotton (Gossypium hirsutum L.) based cropping systems in Australian Vertosols are sparse. Our objective was to quantify soil water storage, drainage, and leaching in four cotton-based cropping systems sown on permanent beds in an irrigated Vertosol with subsoil sodicity. Drainage was inferred using the chloride mass-balance method, and soil water storage and leaching were measured with a neutron moisture meter and ceramic-cup water samplers, respectively, from September 2005 to May 2011 in an ongoing experiment. The experimental treatments were: CC, cotton monoculture, summer cotton with winter fallow; CV, cotton–vetch (Vicia benghalensis L.) rotation with vetch stubble retained as in-situ mulch; CW, cotton–wheat (Triticum aestivum L.), with wheat stubble incorporated and a summer–winter fallow; and CWV, cotton–wheat–vetch, with wheat and vetch stubbles retained as in-situ mulch and summer and spring fallows. Soil water storage was generally highest under CW and CWV and least under CV. An untilled short fallow (~3 months) when combined with retention of crop residues as surface mulch, as in CWV, was as effective in harvesting rainfall as a tilled long fallow (~11 months) with stubble incorporation, as in CW. Drainage under cotton was generally in the order CW ≥ CWV > CC = CV, all of which were considerably greater than drainage during fallows. Except for very wet and dry winters, drainage under wheat rotation crops was greater than that under vetch. During wet winters, saturated soil in the 0–0.6 m depth of treatments under fallow resulted in more drainage than in the drier, cropped plots. No definitive conclusions could be made with respect to the effects of cropping systems on salt and nutrient leaching. Leachate contained less nitrate-nitrogen, magnesium, and potassium, but leachate electrical conductivity was ~6 times higher than infiltrated water. The greater salinity of the leachate may pose a risk to groundwater resources.

Soil organic carbon concentrations and storage in irrigated cotton cropping systems sown on permanent beds in a Vertosol with restricted subsoil drainage

“…Average drainage out of the root-zone was~25 mm per cotton season (October-May), approximating <3% of total water inputs (Hulugalle et al 2013). Average drainage out of the root-zone was~25 mm per cotton season (October-May), approximating <3% of total water inputs (Hulugalle et al 2013). Between 2002 and 2010, soil quality declined in this site, with greatest falls occurring with CV (see below) and least with the cropping systems that included a wheat crop.…”

“…In contrast, for the surface 0.6 m ESI averaged 0.10 and ESP 4. Average drainage out of the root-zone was~25 mm per cotton season (October-May), approximating <3% of total water inputs (Hulugalle et al 2013). Average drainage out of the root-zone was~25 mm per cotton season (October-May), approximating <3% of total water inputs (Hulugalle et al 2013).…”

“…Sowing two or three rotation crops after cotton is, however, unusual. In one of the few studies that investigated including a third crop such as a legume in a two-crop, cotton-based rotation, water conservation and N stocks were enhanced but overall productivity and soil quality was not (Hulugalle et al 2011(Hulugalle et al , 2012a(Hulugalle et al , 2013Powell and Scott 2011). In contrast, Power et al (2011) reported that a third crop (legume) was able to reduce risk, improve water use, and reduce N inputs.…”

Aquifer heterogeneity and response time: the challenge for groundwater management

“…On the alluvial plain, areal recharge estimates range from 32 mm year -1 in the Upper Namoi (SWS 2012) to 0 mm year -1 in the western portion of the lower Namoi . Areal rainfall, irrigation deep drainage (Silburn and Montgomery 2004;Hulugalle et al 2010Hulugalle et al , 2012, and valley edge recharge do not cause visually discernible signals in the groundwater hydrographs.…”

Hydrological and water-use efficiency implications of geomorphological stratification in palæochannels in the Northern Murray–Darling Basin

“…Recent studies have therefore tried to elucidate the effects of crop rotation (Hulugalle et al 2012;Weaver et al 2013), irrigation methods and timing (Gunawardena et al 2011; Ringrose-Voase and Nadelko 2011) land-use patterns Tolmie et al 2011) and regional hydrogeology (Acworth and Timms 2009) on these water and salt flows. Therefore, of particular interest to this study are: (i) what are the specific contrasting biophysical and hydraulic properties that make palaeochannels potential risk zones for irrigation management; and (ii) what management strategy is needed to maximise irrigation resources and minimise ecological impact.…”