Impact of a Novel Water-Saving Subsurface Irrigation System on Water Productivity, Photosynthetic Characteristics, Yield, and Fruit Quality of Date Palm under Arid Conditions

Maged Elsayed Ahmed Mohammed,Mohammed Refdan Alhajhoj,Muhammad Munir,Hassan Muzzamil Ali-Dinar

doi:10.3390/agronomy10091265

Maged Elsayed Ahmed Mohammed, Mohammed Refdan Alhajhoj + Show 2 more

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https://doi.org/10.3390/agronomy10091265

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Abstract

Water scarcity is a major constraint in arid and semi-arid regions. Crops that require less irrigation water and those, which are considered drought-tolerant such as date palm (Phoenix dactylifera L.), are dominant in these regions. Despite the tolerance of these crops, the development of technologies that ensure efficient use of irrigation water is imperative. Taking these issues into consideration, the study was conducted to investigate the impact of limited irrigation water using a new subsurface irrigation system (SSI) on gas exchange, chlorophyll content, water use efficiency, water productivity, fruit physicochemical characteristics, and yield of date palm (cv. Sheshi). The impact of the SSI system was compared with two surface irrigation systems, namely, surface drip irrigation (SDI) and surface bubbler irrigation (SBI). The field experiment was carried out during 2018 and 2019 at the Date Palm Research Center of Excellence, King Faisal University, Kingdom of Saudi Arabia. The annual crop evapotranspiration (ETc) was 2544 mm. The applied irrigation water was set at 50%, 75%, and 125% of ETc for SSI, SDI, and SBI, respectively, which were based on the higher crop water productivity recorded in an initial field study. The total annual volume of water applied for SSI, SDI, and SBI was 22.89, 34.34, and 57.24 m3 palm−1, respectively. The crop water productivity (CWP) at the SSI system was significantly higher, with a value of 1.15 kg m−3, compared to the SDI (0.51 kg m−3) and SBI systems (0.37 kg m−3). The photosynthetic water use efficiency (WUE) was 10.09, 9.96, and 9.56 μmol CO2 mmol−1 H2O for SSI, SBI, and SDI, respectively. The maximum chlorophyll content (62.4 SPAD) was observed in SBI, followed by SSI (58.9 SPAD) and SDI (56.9 SPAD). Similarly, net photosynthesis and the transpiration rate were significantly higher in SBI and lowest in SSI. However, the SSI system substantially increased palm yield and enhanced fruit quality. The new SSI system, through its positive impact on the efficiency of irrigation water use and enhancement on fruit yield and fruit quality of date palm, seems quite suitable for the irrigation of palm trees in arid and semi-arid regions.

Highlights

Date palm (Phoenix dactylifera L.) is a major crop in most arid and semi-arid regions of the world [1].These regions are generally characterized by water resource scarcity [2]
The present study indicated that the water use efficiency (WUE) based on the net photosynthesis and transpiration rate was higher (10.09 μmol CO2 mmol−1 H2 O) when the palm tree were irrigated by the subsurface irrigation (SSI) system followed by the surface drip irrigation (SDI) (9.96 μmol CO2 mmol−1 H2 O) and surface bubbler irrigation (SBI)
The results showed an increase of 17.9% in crop yield with 67.8% in crop water productivity (CWP) compared to the SBI system, though the annual volume of water applied by SSI was 60% lower than that of the SBI system

Summary

Introduction

Date palm (Phoenix dactylifera L.) is a major crop in most arid and semi-arid regions of the world [1]. These regions are generally characterized by water resource scarcity [2]. Agronomy 2020, 10, 1265 such regions, inefficient use of water still prevails and can be commonly noticed on date palm farms, which is blamed for the depletion of precious groundwater sources [3]. Highest date palm production is achieved when providing full irrigation water requirements by traditional methods, the same production can be achieved with significantly less water application, up to 50% less, by using modern irrigation systems [5]

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