Yield and quality responses of drip-irrigated spinach to different irrigation quantities in a semi-arid region with a high altitude

The effect of different irrigation quantities on the growth, marketable yield, crop quality (antioxidant activity, mineral and total phenolic content) and irrigation water use efficiency (IWUE) of spinach grown in a semi-arid region of high altitude (1795 m a.s.l.) was determined. Plants were irrigated with three different irrigation quantities which determined considering 100 (I1), 85 (I2) and 70% (I3) of the evaporation obtained from a Class A pan. Irrigation quantities in the I1, I2 and I3 treatments as two years average were 290, 264.3 and 238.6 mm, respectively. The I1 treatment provided the highest growth, marketable yield (28.06 t*ha) and IWUE (9.7 kg*m). However, mineral and total phenolic content and antioxidant activity in the leaves of spinach were significantly higher under lower water application conditions. The I2 treatment resulted with the highest antioxidant activity and content of N, K, Mg, Na, Fe, Cu and total phenolics. As a result of the study, I1 treatment in spinach production could be suitable for water sufficient regions due to higher yield and IWUE. However, I2 treatment may be more appropriate for water scarce semi-arid regions of high altitude for obtaining higher minerals and antioxidant activity.