استخدام نظام التصنيف العددي في تصنيف بعض الترب العراقية باستخدام بعض صفاتها

Abstract

Abstract : This study was conducted on some soils in different regions from Iraq, according to previous studies in soil survey and classification.The aim was to classify the soils numerically, representing a different physiographic units using the morphological characteristics of soils as well as physical and chemical characteristics and to compare the results with those of USDA system. Sixteen sites were elected in the following areas: Anbar, Mosul, Arbil, Sulaymaniyah, and Diyala. The soil individuals were classified numerically, using the method of Ward proposed by Ward (1963) to reduce the sum of squares of differences from each individual (group) to the center of the group. The results pointed out that two soil individuals of Diyala were compatible due to the greater homogeneity in some morphological characteristics used in numerical taxonomy such as type of structure of B horizon , thickness of horizons A, B, thickness of soil solum, Hue, Value, and Chroma. It was noted harmony in some chemical characteristics of the organic matter content, pH reaction and cation exchange capacity. Also it was indicated the Agreement in the physical characteristics of the values of bulk density and content of clay and silt.These soil individuals were classified according to USDA system to subgroup Typic Calciargids. The similarity indices of the soil individuals within the areas under study were as follows: similarity index between soil individuals of Diyala equal to 0.966; similarity index between soil individuals of Arbil and Mosul equal to 0.907; and similarity index between soil individuals of Sulaymaniyah equal to 0.818. The results confirmed the validity of the use of morphological (semi_quantitative), with the physical and chemical characteristics in the numerical taxonomy of soils and compatibility with the USDA system.