Author name:
علاء حسين علي البدران
Supervisor name:
محمد مالك ياسين
Abstract:
Three laboratory experiments were conducted to study the ionic exchangeable relation for sodium - calcium cations to calculated the exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR).1 - First experiment was included to use two standard clay minerals, kaolinite (1 : 1) layers and montmorillonite (2 : 1) layers with solutions of several SARs (2,4,8,24,48 and 96) (m mole L - 1)0.5 at four ionic strength (20,40,80 and 240 ) mmol L - 1. The results showed, increasing ESP with increasing SAR for both clay minerals. The equations (liner, exponential, logarithm, quadratic, power, ,exponential curved, U. S. salinity laboratory and developed ) were used to description the relationship between ESP and SAR by correlation (R2) and the root of mean standard error (rmse). The exponential curve equation ESP= A+ B(D)SAR which (A, B and D) coefficients regression was more capability in prediction of ESP from SAR and it be the nearest to really value ESP comparing with other equations at various ionic strength and for both clay minerals. This equation tended to show the increase of ESP values with increasing ionic strength for kaolinite mineral and raising the constant (A), but not with montmorillonite. Also the results showed high significant differences (p<0.01) for coefficients regression parameters (A, B and D) at ionic strength (40, 80 and 240) mmole L - 1 between two minerals, while the significant was in coefficient (D) in 20 mmole L - 1 only. The Vanslow selectivity coefficient (Kv) gave the best description of the prefence ability of the exchange surfaces to cations Na - Ca exchange comparing with Gapon selectivity coefficient (KG).2 - Second experiment : Twenty seven locations represents Basrah province soils (1 - AL - Fao, 2 - AL - Maamer, 3 - ASSiba, 4 - AL oga, 5 - Naher kouz, 6 - Abo Mughera, 7 - Assibiliat, 8 - Mehalla, 9 - Hammdan, 10 - yousfan, 11 - Mehagran, 12 - Auassyan, 13 - AL - karma, 14 - AL - Hartha, 15 - Adear , 16 and 17 - (Ahwar - Adear) two places from marshes of Adear, 18 - Asharsh, 19 - AL - Qurna, 20 - AL - Hweer, 21 and 22 - (Ahwar AL - Hweer) two places from marshes of AL Hweer, 23 - AL - Mudayna, 24 and 25 - (Ahwar AL - Mudayna) two places from marshes of AL Mudayna , 26 - Azubair, 27 - Saffwan) with depth (0 - 30) cm were selected to study sodium - calcium exchange and measurements ESP and SAR. Generally the results referred to the soils contain the clay minerals montmorillonite, chlorite, illite, kaolinite, chlorite - montmorillonite interstratification and illite - Palygorskite interstratification with the different rates. After testing the previous equations for relationship between ESP and SAR for the soils, we found the exponential cure was a best equations (R2= 0.920), (rmse= 7.740) for describe the ESP - SARI116relationship comparing with others studying equations. The salinity factor had clear role in effect of the measuring ESP from ESP - SAR relationship, but there was no apparent influence for minerals composition, may be because the interaction between clays type, minerals ratio and soil properties. Also (Kv) gave more accuracy in description for surfaces preference of sodium - calcium exchange compared with (KG).3 - Third experiment : Five types of soils were selected from prior locations in second experiment, which are different in SAR, ESP , EC and other properties (1 - AL - Fao, 8 - Mihalla, 16 - Ahwar Ader first location ,22 - Ahwar AL - Hweer second location, 23 - AL Mudayna) were placed in plastic column to 30 cm depth and 10 cm diameter. Four irrigation water salinity of (1,4,8 and12)ds m - 1 were irrigated to field capacity for ten times. After drying the columns were divided to two parts, 0 - 15 and 15 - 30 cm, then the prior equation were as 1st and 2nd experiments. The results showed that superiority equation of exponential curved compared with other equations in ESP from SAR (R2=0.94) and (rmse=14.379). The study showed to potentiality of alteration the soils to sodic salinity soils with raising of salt concentrations as result from irrigation with high water salinity. Also the soil Colloids surfaces showed more sodium preference comparing with calcium through the selectivity coefficient (Kv) in particular with irrigation water salinity increasing except the hoor. Adear soil of first location for two depths which showed its surfaces more calcium preference compared with sodium (Kv<1) in spite of soil salinity increasing.
