Kinetic of Calcium and Magnesium Released from Calcareous Soils Irrigated by Different Water Quality

Abstract

Abstract The objective of present investigation was to study the kinetics of Ca + Mg – minerals dissolution from calcareous soils of north Iraq and to compute diffusion coefficient rates in soils. Therefore. a laboratory procedure was conducted to evaluate the rate of water quality to release the exchange and mineral dissolution from miscible displacement experiments on undistributed soil columns. Soil columns collected from three sites at North Jazera project (Rabia City) Mosul governorate. Water quality (EC. SAR 0.4. 10.45. 2.07 and 7.05) allowed to flow in the columns until Pv10. The results showed a high amount of mineral – dissolution (Ca + Mg) (0 – 725) Cmole.Kg while a low amount release from exchange phase (0 – 636) Cmole.Kg-1. The results also reflected to high mineral dissolution amount by well water also a low amount of dissolution noticed by river water (Tigris river). A mineral – dissolution amounts were described kinetically by using five different models and equations (zero order. first order. parabolic diffusion. Elovichand power equations). Pathway reaction was consisted from two stages along to period of reaction. parabolic diffusion equation gave a best description of Mineral – dissolution release – and there were some deviation. There was same deviation in diffusion plots during the initial period of description it indicated that diffusion – controlled exchange at sites an external surface and slowly mineral dissolution high rate coefficients of Ca + Mg release where (0 – 592. 0-708. and 1461 × 10-4 mg.kg-1.t1/2 in Alkana and Botha and Till Talb respectively that irrigated by well water . while the low values were (0.238. 0.262 and 473 × 10-4) for Botha. Till Talb and Alkana soils respectively after irrigated by river water (Tigris river)

Keywords

Ca, Ma, Water quality