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Assiut University (2018)

Determining and Mapping Soil Nitrogen, Phosphors and Potassium Contents Using Geostatistical Technique in El-Dakhla and El-Kharga Oases

Farghaly, Samar Swify.

Titre : Determining and Mapping Soil Nitrogen, Phosphors and Potassium Contents Using Geostatistical Technique in El-Dakhla and El-Kharga Oases

Auteur : Farghaly, Samar Swify.

Etablissement de soutenance : Assiut University

Grade : Master in Agricultural Sciences 2018

Résumé
The areas under investigation are located at El-Kharga and El-Dakhla oases, New Valley Governorate, Egypt. The study areas included four sites, two sites in El-Kharga oasis (El-Monira and Bolaq) and the other two sites in El-Dakhla oasis (Zakhera and Mut). The major goal of this study was evaluating and mapping the spatial variability of the soil available N, P and K using geostatistical technique. So, the objectives of this study were analyzing some physical and chemical properties of soil,determine and assessment the availability of soil N, P and K contents,evaluate the spatial variability of soil N, P and K by using geostatistical analysis andproduce maps for the spatial variation of soil N, P and K contents and some soil physico-chemical properties using ArcGIS. One hundred and thirty–seven soil samples (50, 25, 30 and 32 samples) were collected from sites A (El-Monira), B (Bolaq),C (Zakhera) and D (Mut), respectively to represent the study areas. The samples were collected from the surface layer (0-25 cm) of the soil. They were taken using the systematically sampling grid within a distance between two consequent samples of 200m in sites A, B and C and 50m in site D. The soil available N, P and K and some physical and chemical analyses of the soil samples (soil texture, SP, pH, ECe, OM and CaCO3) were determined according standard methods. Data analyzedby using SAS software version 11 to get the statistical analysis including minimum, maximum, range, mean, standard deviation, coefficient of variation, skewness and kurtosis, which are generally accepted as indicators of the central tendency. Geostatistical analyses and the distribution maps of the soilavailableN, P and K contents and some physico-chemical properties were produced by ArcGIS (10.2.2). In ArcGIS geostatistical analyst, the histogram and normal QQPlots tools were used to see what transformations were needed to make the data more normally distributed. Histogram and normal QQPlots analysis were applied for soil available N, P and K of the investigated soil samples to check its data to see if it has normal distribution or not. Logarithmic transformation had been used for N, P and K content data to normalize too highly skewed and outlier data sets because kriging methods work best if the data is approximately normally distributed.Ordinary Kriging (OK) method was used in the present study as interpolation method because it is simple and has high accuracy for prediction in comparison to other kriging methods.

Présentation étendue (EULC)

Page publiée le 24 décembre 2020