Articles | Volume 19, issue 12
Hydrol. Earth Syst. Sci., 19, 4877–4891, 2015
https://doi.org/10.5194/hess-19-4877-2015
Hydrol. Earth Syst. Sci., 19, 4877–4891, 2015
https://doi.org/10.5194/hess-19-4877-2015

Research article 21 Dec 2015

Research article | 21 Dec 2015

Green and blue water footprint reduction in irrigated agriculture: effect of irrigation techniques, irrigation strategies and mulching

A. D. Chukalla, M. S. Krol, and A. Y. Hoekstra A. D. Chukalla et al.
  • Twente Water Centre, University of Twente, Enschede, the Netherlands

Abstract. Consumptive water footprint (WF) reduction in irrigated crop production is essential given the increasing competition for freshwater. This study explores the effect of three management practices on the soil water balance and plant growth, specifically on evapotranspiration (ET) and yield (Y) and thus the consumptive WF of crops (ET / Y). The management practices are four irrigation techniques (furrow, sprinkler, drip and subsurface drip (SSD)), four irrigation strategies (full (FI), deficit (DI), supplementary (SI) and no irrigation), and three mulching practices (no mulching, organic (OML) and synthetic (SML) mulching). Various cases were considered: arid, semi-arid, sub-humid and humid environments in Israel, Spain, Italy and the UK, respectively; wet, normal and dry years; three soil types (sand, sandy loam and silty clay loam); and three crops (maize, potato and tomato). The AquaCrop model and the global WF accounting standard were used to relate the management practices to effects on ET, Y and WF. For each management practice, the associated green, blue and total consumptive WF were compared to the reference case (furrow irrigation, full irrigation, no mulching). The average reduction in the consumptive WF is 8–10 % if we change from the reference to drip or SSD, 13 % when changing to OML, 17–18 % when moving to drip or SSD in combination with OML, and 28 % for drip or SSD in combination with SML. All before-mentioned reductions increase by one or a few per cent when moving from full to deficit irrigation. Reduction in overall consumptive WF always goes together with an increasing ratio of green to blue WF. The WF of growing a crop for a particular environment is smallest under DI, followed by FI, SI and rain-fed. Growing crops with sprinkler irrigation has the largest consumptive WF, followed by furrow, drip and SSD. Furrow irrigation has a smaller consumptive WF compared with sprinkler, even though the classical measure of "irrigation efficiency" for furrow is lower.

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Short summary
This paper provides the first detailed and comprehensive study regarding the potential for reducing the consumptive WF of a crop by changing management practice such as irrigation technique, irrigation strategy and mulching practice. If we consider all the cases of drip or subsurface drip irrigation with synthetic mulching, including all crops and environments, we find an average consumptive WF reduction of 28-29%. The corresponding blue WF reduction is 44% and the green WF reduction 14%.