Response of selected indigenous dryland agroforestry tree species to salinity and implications for soil fertility management

Abstract

Salt tolerant plants are known to remove excess soluble salts from the soil and thus may be used in land reclamation.We studied the responses of the trees, Balinites aegyptiaca L. (Zygophyllaceae), as well as the Fabaceae, Acacia tortilis (Forssk) Hayne, and Tamarindus indica L. to salinity. Three experiments were conducted on: germination, in the laboratory; seedling performance in a lath house; and, the impact of the tree species on soil productivity in the field in Afar regional state along the Awash river, eastern Ethiopia. Mixtures of salts, composed of chlorides and sulfates were tested at different concentrations in both germination and lath house experiments in randomized complete block designs. Seedling root collar diameter and height were measured every two weeks. Soil samples were collected from randomly selected pots to examine the effect of salinity on soil properties. The effects of trees on in situ soil productivity was studied by collecting 72 soil samples at different distances from the tree and different soil depths. The soil productivity index was calculated by summing the products of sufficiency of available water capacity, aeration, bulk density, pH, electrical conductivity and the Weighting factor for each layer. The study revealed that germination percentage and rate decreased significantly with increasing salt concentrations. The effects of the three tree species on soil properties were significantly different at 12.2 dS m -1 salinity level compared to the control. A. tortilis was the least salt-sensitive. Balancing the key requirements of adequate germination and growth and the ability to reduce the salt concentration of the soil solution, B. aegyptiaca is the species with the most potential. Therefore, the study suggests to use B. aegyptiaca as agroforestry trees in the form of parkland in arid and semi-arid areas where salinity problems are prominent.

Salinity-induced changes in the morphology, physiology, and anatomy of seeds and seedlings of smooth narra (Pterocarpus indicus Willd. f. indicus)

“…Jimenez-Casas and Zwiazek (2014) observed that Pinus leiophylla's stem diameter growth decreased with increasing NaCl concentration. Also, the RCD of a native dryland agroforestry tree species, Acacia tortilis, was severely impacted by salinity (Seid et al 2016). For Senegalia senegal, Vachellia seyal, and Prosopis juliflora, Fall et al (2016) observed that salinity reduced significantly the RCD.…”

“…For Senegalia senegal, Vachellia seyal, and Prosopis juliflora, Fall et al (2016) observed that salinity reduced significantly the RCD. In contrast, salinity had no effect on the RCD of Balanites aegyptiaca (Seid et al 2016). In addition, the greenhouse experiment of Duan (2015) demonstrated the effectiveness of N fertilization in improving the growth of seedlings in a saline growth media, resulting in improved RCD growth for both Pinus contorta and Picea glauca seedlings.…”

Modeling impacts of climate change on the geographic distribution and abundances of Tamarindus indica in Tigray region, Ethiopia

“…Tamarindus indica L. (hereafter T. indica) is one of the multipurpose trees in sub-Saharan zones and traditionally builds resilience to the farming systems [ 7 , 8 ]. Beyond maintaining ecological sustainability [ 9 , 10 ], T. indica is an indigenous semi-evergreen tree species of the Fabaceae family, widely distributed across the sub- and semi-arid tropics [ 7 , 11 ] and is preferred for its wild edible fruit and timber [ 7 ], fodder for animals [ 12 ], medicinal value [ [13] , [14] , [15] , [16] , [17] , [18] ], food [ 18 , 19 ] and improve soil fertility [ 9 , 10 ].…”