Influence of different drip irrigation strategies on irrigation water use efficiency on chufa (Cyperus esculentus L. var. sativus Boeck.) crop

Abstract

Chufa is a typical crop in Valencia, Spain, where it is cultivated in ridges with furrow irrigation. It uses large volumes of water, and thus, different studies have been undertaken to maximize irrigation water use efficiency to obtain important water savings. Particularly, different values for turning water on, considering the basis of volumetric soil water content were analysed in drip irrigation. It was reported that starting each irrigation event when the volumetric soil water content dropped to 90% of the field capacity resulted in the best yield, and the best irrigation water use efficiency was obtained when it dropped to 80% of the field capacity. However, these results may be improved by defining the optimum criteria for turning water off, which is the aim of the present research. This investigation, conducted in 2015, 2016 and 2017, analises the productive response of the drip irrigated chufa crop, determining the yield and the irrigation water use efficiency. The volumetric soil water content was monitored using multi-depth capacitance probes, with sensors at 0.10, 0.20 and 0.30 m below the top of the ridge. Each irrigation event started when the volumetric soil water content at 0.10 m dropped to 85% of field capacity. Three irrigation strategies were considered. T1: each event resulting in water being turned off when the sum of the volumetric soil water content values that were measured at 0.10, 0.20 and 0.30 m reached the corresponding field capacity value; T2: turning water off in each event when the volumetric soil water content values that were measured at 0.20 m reached the corresponding field capacity value; and T3: each irrigation event applying 8.5 mm in 2015 and 2016, as well as 9.8 mm in 2017. Overall, the T2 strategy resulted in the largest yield, and T3 resulted in the highest irrigation water use efficiency in 2015 and 2016. The average tuber weight and dry matter content did not differ between the irrigation strategies.