Spatial Distribution of Soil Organic Matter and Soil Organic Carbon Stocks in Semi-Arid Area of Northeastern Syria

Abstract

Although soil organic matter (SOM) forms a small portion of the soil body. Nevertheless, it is the most important component of the soil ecosystem, as well as of the carbon global cycle. In the semi-arid environment, there has been little research on the spatial distribution of SOM and soil organic carbon (SOC) stock. In this study, stratified random samples of total 30 soils were collected from two different soil depth (topsoil, subsoil) of Al Balikh plain and used for mapping the spatial variability of SOC and to estimating the SOC stock. The result showed that the values were relatively homogenate, with the normal decreasing trend with increasing the depth. The standard deviation (Std. D) for both SOC and SOC stock indicates homogeneous and absence of outliers values, whereas the coefficient of variation (C.V) indicates non-dispersion and clustering of values around the average. SOC was 0.38%, 0.17% in topsoil and subsoil respectively; the corresponding averages of SOC stock were 1.23 kg•m −2 and 1.14 kg•m −2 respectively, these values reflecting typical characteristics of poor SOC semi-arid soil. The correlation between SOC and SOC stock was (R 2 = 0.996, p < 0.001) in topsoil and it was (R 2 = 0.941, p < 0.001) for subsoil. The semivariograms were indicated that both SOC and SOC stock were best fitted to the exponential model. Nugget, range, and sill were equal to 0.002, 0.036, and 0.044, respectively for SOC in topsoil, and 0.014, 0.071, and 0.081, for SOC in the subsoil. For SOC stock, it was 0.0, 0.036, and 0.0508, respectively in topsoil. In the subsoil, the values were 0.1899, 0.086, and 4.159, respectively. SOC and SCO stock in both two layers are shown a strong spatial dependence, for which were 4.3, 17.2 for SOC in topsoil and subsoil respectively, and 0.0, 4.5 for SOC stock in topsoil and subsoil respectively, thus, which can be attributed to intrinsic factors.

Soil Constraints in an Arid Environment—Challenges, Prospects, and Implications

“…This indicates the need for developing and utilizing the land, especially previously overlooked areas. In this respect, the large soil resources of arid regions provide a potential agricultural habitat and comprise around 16% of the planet's land surface [3]. Most developing nations with rapid population expansion are located in arid and semi-arid regions.…”

Soil Carbon and Nitrogen Stock and Their Spatial Variability Along an Exclosure Chronosequence at Kewet District, Central Dry Lowlands of Ethiopia

“…Overall, the range suggests that SOC stock shows strong spatial autocorrelation than TN stock in all the exclosures and adjacent open grazing. The slightly higher nugget of TN than SOC stock implies a random and inherent variability of TN stock (Husein et al, 2019).…”

Variation of soil organic carbon across different land covers and land uses in the greater Gaborone region of Botswana

“…At the sampling points, soil samples were collected from a depth of 30 cm for SOC content, pH, and soil texture determination. Studies have shown that SOC is higher in the topsoil and decreases exponentially with depth [32][33][34]. In addition, the 30 cm soil depth is considered the most relevant soil depth for SOC estimation because it is the most biologically active layer of the soil [35] and is most affected by land management practices, particularly in the agricultural system (ploughing) [36].…”