Delineating reclamation zones for site-specific reclamation of saline-sodic soils in Dushak, Turkmenistan

Abstract

Soil salinization is the widespread problem seriously affecting the agricultural sustainability and causing income losses in arid regions. The major objective of the study was to quantify and map the spatial variability of soil salinity and sodicity. Determining salinity and sodicity variability in different soil layers was the second objective. Finally, proposing an approach for delineating different salinity and sodicity zones was the third objective. The study was carried out in 871.1 ha farmland in Southeast of Dushak town of Ahal Province, Turkmenistan. Soil properties, including electrical conductivity (EC), soil reaction (pH), sodium adsorption ratio (SAR), calcium carbonate and particle size distribution (clay, silt and sand fractions) in 0–30, 30–60, 60–90 and 90–120 cm soil layers were recorded. The EC values in different soil layers indicated serious soil salinization problem in the study area. The mean EC values in 0–90 cm depth were high (8 dS m-1), classifying the soils as moderate to strongly saline. Spatial dependence calculated by the nugget to sill ratio indicated a strong spatial autocorrelation. The elevation was the primary factor affecting spatial variation of soil salinity in the study area. The reclamation of the field can be planned based on three distinct areas, i.e., high (≥12 dS m-1), moderate (12–8 dS m-1) and low (<8 dS m-1) EC values. The spatial trend analyses of SAR values revealed similar patterns for EC and pH; both of which gradually decreased from north to the south-west. The amount of water needed to leach down the salts from 60 cm of soil profile is between 56.4–150.0 ton ha-1 and the average leaching water was 89.8 tons ha-1. The application of leaching water based on the amount of average leaching water will result in higher or lower leaching water application to most locations and the efficiency of the reclamation efforts will be low. Similar results were recorded for sulfur, sulfuric acid and gypsum requirements to remediate sodicity. The results concluded that the best management strategy in planning land development and reclamation schemes for saline and sodic soils require accurate information about the spatial distribution of salinity and sodicity across the target area.

Potential of Landsat 8 OLI for mapping and monitoring of soil salinity in an arid region: A case study in Dushak, Turkmenistan

“…The information on spatial distribution of salinity is important to determine better management decisions with the goal of maximizing agricultural productivity in saline soils [ 41 ]. This study revealed that soil salinity could be successfully predicted with medium resolution satellite images and multivariate regression models.…”

Identification of Halophilic and Halotolerant Bacteria from the Root Soil of the Halophyte Sesuvium verrucosum Raf

“…Zinc in saline soils is a limited element; therefore, the use of solubilizing bacteria could become a great resource to improve plant nutrition [ 64 ]. An alternative for the recovery of saline soils is the release of calcium from native calcium carbonate which—by exchange with sodium in the soil—can reduce the sodium concentration by subsequent washing [ 65 ]. These bacterial plant growth-promoting mechanisms exist due to the production of organic substances that are capable of causing responses in plant cells at biochemical, physiological and morphological levels [ 66 ], which in addition to participating in biogeochemical cycles, make organic and inorganic compounds available that can be later used by plants subjected to salt stress [ 60 ].…”

Extenuating the Detrimental Effects of Sodic Water on Agronomic, Ionic, and Quality Attributes of Fodders

“…Gypsum, a widespread soluble calcium (Ca 2+ ) source, can aid alteration in sodium-rich soils (Sundha et al, 2020;Gunal, 2021). Lime and gypsum comprising calcium (Ca 2+ ) can alter sodium ions during leaching at exchange sites of cations.…”