Determination of regression equations to predict soil extract salinity from aqueous soil samples (1:2 and 1:5) for calcareous and non-calcareous loamy soils

摘要

The aim of the study was to reveal regression equations to predict soil extract salinities (ECe) for calcareous and non-calcareous soils. For this purpose, 12 calcareous and 12 non-calcareous soil samples were artificially salinizedby 1.0,5.0 and lOdSm~(-1) saline waters which were prepared witl NaCl. In order not to disturb the homogeneity of application of each sample, the saline waters were added to unapplied soils by the ratio of l.T(w/ w), and then oven dried at 105°C until reaching constant weight to prepare the saline soils to analyze. Hence, 3 salinity levels (1.0, 5.0 and 1( dSm~(-1)), 24 soil samples (12 calcareous and 12 non-calcareous) and 3 methods (EC_e, EC_(1:2) and EC_(1.5) ), total of 216 analyzes were performed. Saturatiot percentage of soils were recorded in order to recalculate aqueous soil samples back to soihwater ratio at saturation level. Thus, 8 regression equations were developed for specified conditions such as i) four equations for direct conversion from EC_(12)or EC toEC_e, where there was no data on soihwater ratio at saturation point, for calcareous and non-calcareous conditions andii) another four equations were calculated by soil: water ratio ai saturation point from EC_(12)or EC_(15) to EC_e, on where there weredata on soihwater ratio at saturation point, for calcareous and non-calcareous conditions.