Spatial Variability of Some Soil Chemical Proprieties in Jeffara Plain, Libya (Case Study: Tripoli, Wadi Almjainin and Bin Ghashir)*

Abstract

Determining variabilities of soil properties is important for ecological modeling, environmental predictions, precise agriculture, and management of natural resources. This study was aimed to examine Kriging and Inverse distance weight (IDW) to predict the spatial variability of Exchangeable Sodium Percentage (ESP), Cation Exchange Capacity (CEC) and Calcium Carbonate Percentage (% CaCo₃). The study area selected for this work consists of Tripoli, Wadi Almjainin, and Bin ghashir, soil profile sheets.

Data for 250 randomly distributed representing soil profiles were encoded in spreadsheets, 225 of them were used for predicting the spatial variability in the GIS environment for ESP, CEC and % CaCo₃. The rest of Data (i.e. 25 representative soil profiles) were utilized to evaluate the maps produced using Kriging or IDW methods.

The results showed that using Simple Kriging method for spatial prediction of ESP, CEC and % CaCo₃ was unsuitable due to the higher range of Nugget-Sill Ratio (i.e. spatial dependency). Whilst the result produced using IDW method was more trustable because the values of RMSE and R² for all the IDW maps were within the acceptable range. The study suggested adopting the Geostatistical methods for studying spatial prediction for different soil proprieties.

Key Words: Kriging, Inverse Distance Weight (IDW), ESP, CEC, CaCO₃.

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* Full article in the Arabic Copy of this journal.

Corresponding Author: Mukhtar Mahmud Elaalem. Dep. of soil and water, Fac. of Agriculture, Univ. of Tripoli, Tripoli, Libya.

Phone:.+218925080367.  e-mail:mukhtarelaalem@yahoo.com

Received: 26/2/2017

Accepted: 26/4/2017