Furrow-irrigated chufa crops in Valencia (Spain). I: Productive response to two irrigation strategies

Chufa (Cyperus esculentus L. var. sativus Boeck.) is an important vegetable crop in Valencia (Spain), where its tubers are used to produce a refreshing drink called 'horchata'. Water is relatively inexpensive, there are no data regarding the volumes of water used to grow chufa, and the irrigation water use efficiency (IWUE) has neither been determined. The aim of this research was to compare the productive responses of the chufa crop to two irrigation strategies (IS). The volumetric soil water content (VSWC) was monitored with capacitance sensors. Trends in VSWC were used to determine the in situ field capacity (FC), beginning each irrigation event when the VSWC reached either approximately 45% (H1) or 60% (H2) of the FC at a soil depth of 0.10 in. The experiments were conducted over three consecutive seasons. An area velocity flow module measured the water flow. The yields, the water volumes used, and the IWUE were calculated. Plants were periodically sampled and the harvest index and relative growth rate were determined. The yield was affected by the year and by the IS. The greatest yields were obtained with the H2 strategy (on average 2.18 kg m(-2) for H2 vs. 1.94 kg m(-2) for H1; p <= 0.01), and the average tuber weight (ATW) was affected (p <= 0.01) by the year and IS interaction. IWUE was affected by the year, and none of the considered factors affected the harvest index (p <= 0.05). It can be concluded that maintaining a higher VSWC would increase both yield and ATW without affecting IWUE.