PARTICLE SIZE DISTRIBUTION OF CARBONATE IN SOME CALCAREOUS SOIL SEPARATES OF NORTHERN IRAQ

Abstract

The experiment included calcareous soils samples with different orders classified within the series level from four locations of Northern Iraq namely(Aridisols-453CCW-Talafer) (Iceptisols-452CCF-Ninevah Forest) (Mollisols-653CEE-Zawaita) (Vertisols-452CCW-Batail). Soil samples were fractionated intro coarse sand (200-500m), fine sand (50-200 µ m), coarse silt (20-50µ m), fine silt (2-20 µ m) and clay (<2 m), and the calcium carbonate distribution was determined in each fraction.The results revealed that carbonate particles were concentrated in the coarse separates of Batail, Zawaita and Talafer accounting for 460.0, 457.7 and 461.4 gm.kg-1 respectively. In the Nineveh forest it was 179.2 gm.kg-1. carbonate particles were order as following (coarse sand ,fine sand ,coarse silt ,fine silt and clay fraction) respectively and the calcium carbonate distribution was different within the series level from four locations of Northern Iraq and within soil bedons. The concentration of carbonate particles is indicative of it’s nature whether it is secondary or pedogenic. Statistic a analysis showed a significant positive correlation (r=0.68**) between the percentage of carbonate in soil separates and it’s average diameter.