Under semi-arid conditions, irrigated agriculture faces hard competition for water. It is against this backdrop that appropriate management of irrigation techniques and water resources becomes a major concern. This study investigated the effect of surface (SDI) and subsurface drip irrigation (SSDI) with domestic treated wastewater (TWW) and fresh water (FW) on soil water dynamics, salinity, yield, and mineral nutrition of okra. The experimental design was set-up based on two adjacent plots according to the water quality: Fresh Water (FW) T₁ and domestic Treated Wastewater (TWW) T₂. Results showed that measured soil water contents (SWCs), under TWW treatment (T₂), were greater than their corresponding measurements under FW (T₁), and in particular at 35 cm depth. Meanwhile, for both water qualities, soil Electrical Conductivity (EC) registered at 5 cm depth was higher than those measured at 35 cm, with values ranging from 0.14 to 0.36 mS·cm⁻¹ and from 0.20 to 0.47 mS·cm^−m for T₁ and T₂, respectively. Regarding crop yield, a statistically significant increase (p = 0.05) in okra fresh yield was observed when TWW was used. Fresh yield in SDI was 2.55 t·ha⁻¹ and 3.9 t·ha⁻¹ in T₁ and T₂, respectively. Nevertheless, results indicated that lateral depth did not significantly affect okra fresh yield. Moreover, a significant higher irrigation water productivity (WP_irrig) with TWW (1.08 ± 0.26 and 1.23 ± 0.18 kg m⁻¹) was observed, which was nearly double those obtained with FW (0.72 ± 0.33 to 0.78 ± 0.18 kg m⁻¹). Appropriate use of SSDI with TWW stands as an irrigation management technique to improve yield and irrigation water productivity of okra crops.

Purpose Due to increasing water demand in worldwide, treated wastewater (TWW) will become an important component in agriculture, particularly in countries facing the water scarcity. Using judiciously the already existing water resources in agriculture production can be proved by using efficient irrigation method. MethodsThis study investigates the impact of two irrigation water quality including; treated wastewater (TWW) and tap water (FW) with two modes of drip irrigation; subsurface at different depth (5, 15 and 25 cm depth) and surface drip irrigation on yield production and growth parameters of okra during the 2017 and 2018 growing seasons. Okra was chosen for its economical and nutritional values. Results Results revealed that the maximum agronomic performance of okra was recorded with TWW by comparing it with FW. SDI also offers more reliable growth and yield data than surface irrigation. TWW influenced positively the growth parameters and yield attitudes of okra. Plant height was maximum in WSDI25 treatment with 257 cm and 214 cm, in 2017 and 2018, respectively followed by WSDI15 and WSDI5 then WSDI0. The same order was observed for the different treatments in the plot by irrigated by FW. Fruit number per plant was observed to be maximum in WSDI5 (55.8) and WSDI15 (54.8), and minimum in FSDI0 (33.8) and FSDI5 (33.7). Okra yield was maximum in WSDI5 treatment (4.59 t/ha) and minimum in FSDI0 treatment (2.2 t/ha) in 2017. Conclusion The results of this study showed that application of TWW under (5 -15) cm depth of drip line is recommended for higher productivity of okra.

The authors wish to make the following corrections to the original paper