Furrow-irrigated chufa crops in Valencia (Spain). II: Performance analysis and optimization

Abstract

Chufa (Cyperus esculentus L. var. sativus Boeck.) is a traditional crop in the Mediterranean region of Spain, where it is only furrow irrigated. This article analyzes the irrigation performance for this crop, conducting field studies over three consecutive seasons in Valencia (Spain). Irrigation schedule was based on the volumetric soil water content, which was measured with capacitance sensors. Infiltrability was measured with blocked-furrow infiltrometers. An area velocity flow module measured the water flow, the cross-sectional geometry of furrows was determined using furrow profilometers, and times for advance and recession were recorded. WinSRFR software was used to analyze every irrigation event, determining the application efficiency (AE) and distribution uniformity of the minimum (DU min ), and to optimize the combination of furrow inflow (q) and cut-off time (T co ). Average values obtained for AE were 30. 1%, 25.6%, and 26.7% in 2007, 2008, and 2009, respectively, and the corresponding DU min values were 0.54, 0.61, and 0.67. Optimized results showed that it is possible to reach AE and DU min values up to 87% and 0.86, respectively. However, understanding the q-T co relationship that maximizes both AE and DU min is more important than knowing the specific values. A function that related q and T co was obtained for the typical plot dimensions, and this was validated in 2011. Therefore, this function can be used in most of the plots in the cultivation area.Additional key words: application efficiency; cut-off time; distribution uniformity; furrow inflow rate; irrigation management; vegetable crop. * Corresponding author: bpascual@prv.upv.es Received: 31-07-12. Accepted: 09-01-13.Abbreviations used: AE (application efficiencies); D app (average depth of the water applied to the field); D av (average depth of the water infiltrated to the field); D min (minimum depth of the water applied to the field); D req (average depth of the water required to fill the root zone); DOY (day of the year); DU (distribution uniformity); DU min (distribution uniformity of the minimum); EY (experimental year); FC (field capacity); n (roughness coefficient); Q (water flow); q (furrow inflow); RP (refill point); T co (cut-off time); VSWC (volumetric soil water content.

Response of nutsedge (Cyperus esculentus L. var sativus Boeck.) tuber production to drip irrigation based on volumetric soil water content

“…Three different DI strategies were used (D70, D80 and D90) and irrigation began when the VSWC values at a soil depth of 0.10 m [Pascual-Seva et al (2013b) stated that the maximum root density and water uptake by nutsedge plants occurred at a depth of 0.10 m] dropped to 70%, 80% and 90% of the FC value.…”

Response of drip-irrigated chufa (Cyperus esculentus L. var. sativus Boeck.) to different planting configurations: Yield and irrigation water-use efficiency

“…Within this context, a line of research was initiated to identify the best practices for the management of the irrigation of chufa. The effect of furrow irrigation on chufa yield has been addressed in previous research (Pascual-Seva et al, 2013a, 2013b. In these studies, irrigation was optimised through the development and validation of an empirical function that estimated the optimum irrigation time as a function of flow discharge, and among other indices, the irrigation water-use efficiency (IWUE) was determined.…”