Sustainable cultivation under saline irrigation water: Alleviating salinity stress using different management treatments on Terminalia arjuna (Roxb.) Wight & Arn.

The use of saline water is one likely option for sustainable cultivation of ornamental plants, particularly in waterscarce regions. To assess the feasibility of sustainable cultivation under saline irrigation water (NaCl at 4000 ppm) in such regions, a field experiment was conducted at the nursery of the Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, Egypt, during the seasons of 2015/2016 and 2016/2017, in which five different management treatments (humic acid, proline, gypsum, leaching, and magnetite) were studied to evaluate their effectiveness on alleviating adverse salinity effects on Terminalia arjuna (Roxb.) Wight & Arn. seedling growth, photosynthetic pigment concentration, and leaf chemical constituents. Generally, compared to seedlings irrigated with saline water, most of the treatments caused significant increases in plant height, number of leaves and main roots/plant, stem diameter, leaf area, fresh and dry weights of leaves and main stem and branches, as well as the concentrations of chlorophylls a and b, total carotenoids, N, P, K, Ca, and proline. Moreover, the parameters for treated plants receiving the different management treatments were close to those of plants irrigated with tap water. Na and Cl concentrations were significantly decreased by most of the treatments in comparison to saline water. The most beneficial treatment among all in reducing negative salinity impacts was humic acid, followed by proline, gypsum, leaching, and magnetite. The results of our study indicate positive effects of all treatments, which can be useful in counteracting the negative consequences of the irrigating with saline water. Such treatments, moreover, may prove to be promising approaches in confronting the challenge of achieving sustainable cultivation under saline irrigation water in arid and semi-arid regions.