The obere ngwepịa osisi na-eji maka nhazi nke topsoil na a dịgasị iche iche nke ndị ọzọ ihe; nkewa viscous ka coagulation nchịkọta; ewu na demolition ụlọ ọrụ; agbajikwa mgbe echetakwa; ịgbari ụlọ ọrụ.
