Effect of CaCO3 Form on Soil Inherent Quality Properties of Calcareous Soils

Four soil samples different in there CaCO3 forms contents (total, active and active /total CaCO3) were taken from tillage horizon 0-30 cm depth to study the impacts of CaCO3 form on some soil inherent quality indicators in calcareous soils. Result revealed that the total CaCO3 forms have a great influence on particle size distribution to make it coarser in general comparing with the absence of CaCO3 with soil particles. The increase of active /total (A/T CaCO3%) till 50% has a positive effect on increasing soil electrical conductivity E.C ds.m-1, while increment of A/T CaCO3 over 50% till 70% detrimentally reduced soil E.C ds.m-1 hundred fold. The elevation of (A/T CaCO3%) has inverse correlation with soil cation exchange capacity (CEC Cmole.kg soil). the elevation of (A/T CaCO3%) has inverse correlation with soil cation exchange capacity (CEC Cmole.kg soil) the (A/T CaCO3%) ratio over 56% till 69% significantly improves the mean weight diameter and macro aggregate. In general the optimum total CaCO3 for micro aggregate formation may not exceed 20%. The best Total and (A/T CaCO3%) for better aggregate stability is between 20 to 48% . The proper total calcium carbonate for better total heterotrophic aerobic bacterial activity is around 20% . The best growth of the Azotobacter species which is belonging to non-symbiotic nitrogen fixing bacteria is obtained when total CaCO3 ranges between 10-20% or between 48-56% of (A/T CaCO3%).