Improving yield and Irrigation Water Use Efficiency (IWUE) is important for pistachio cultivation in Iran. Subsurface Drip Irrigation (SDI) is a novel irrigation system that is used by pistachio farmers. Oxygen deficiency could occur in the soil under crops irrigated by SDI, especially in heavy clay soils, due to creation of sustained wetting fronts around emitters. The focus of this work was to evaluate aerated water irrigation (oxygation) under SDI to overcome hypoxia in saline loam silt soil environments on 15 years old pistachio trees in desert climate. Two treatments including F
3 (irrigation frequency once every 3 days without air injection) and F
3-oxygation (irrigation frequency once every 3 days by air injection) were investigated in two years.
The injection of 18% by volume air into irrigation water by SDI resulted in a beneficial effect on yield and IWUE in the second year of experiment; with yield values of 4.9 ton ha
-1 for F
3-oxygation against 4.4 ton ha
-1 for F
3; and IWUE values of 4.2 kg ha
-1 mm
-1 for F
3-oxygation against 3.7 kg ha
-1 mm
-1 for F
3. Decreases in yield and IWUE in the F
3-oxygation in comparison with F
3 were 33.3 and 28.2% in the first year, respectively; but yield and IWUE due to F
3-oxygation were 11.1 and 13.5% greater in the second year compared to F
3, respectively. At the end of the irrigation season, the nitrogen content of the nuts removal in F
3, and F
3-oxygation were 1.9 and 2.1% in the first year and 1.4 and 1.6% in the second year, respectively. The leaf K
+ and nut Fe
2+ concentrations in F
3-oxygation were about 24 and 44% more than F
3, respectively. Leaf area was larger in aeration treatment compared with the control. Overall, these results indicate positive effects of oxygated SDI system on pistachio trees and merit further investigation for improving yield and IWUE.
Article Type:
Original Research |
Subject:
Irrigation and Drainage Received: 2019/06/8 | Accepted: 2020/02/5 | Published: 2020/10/13