Soil Descriptive Parameters and Properties – Interdependence Relationships and Variation Models

Abstract

The study aimed to evaluate the soil descriptor parameters in the case of agricultural land in the pasture category, non-irrigated system, and to evaluate the variation of soil agrophysical properties in relation to textural components. The study area was located within the ATU Ciacova, Timis County, Romania. The soils identified in the study plot were of the type Eutricambosol weakly gleyed, weakly sodicized, and Eutricambosol gleyic, moderately gleyed. The following parameters were considered for the soil characterization: Coarse sand (CS, %), Fine sand (FS, %), Dust (Dst, %), Colloidal clay (CC, %), Physical clay (PC, %), Specific density (SD, g/cm3), Apparent density (SD, g/cm³), Total porosity (TP, %), Aeration porosity (AP, %), Compaction degree (CD, %), Hygroscopicity coefficient (HygC, %), Withering coefficient (WC, %), Field capacity (FC, %), Total capacity (TC, %), Usefull water capacity (UWC, %), and Hydraulic conductivity (HydC, mm/h). The data series showed normal distribution. High variability was recorded for CS and HydC, moderate variability for AP and CD, and low variability for the other parameters and indices. The variable interdependence in intensity and direction of action was recorded between the soil descriptor parameters considered. Parameters HygC, WC, FC, which express the hydrophysical properties of the soil, presented, according to Ordinary Least Squares Regression (OLSR), positive distribution, with Slope a = 0.2425, r² = 0.8854 in the case of HygC, respectively with Slope a = 0.3635, r² = 0.8861 in the case of WC. Under the same analysis conditions, the UWC parameter values ​​presented a negative distribution, with Slope a = -0.2895, r² = 0.8113. Polynomial models described the variation of the HygC, WC, FC and UWC parameters in relation to the soil textural components, in conditions of statistical safety.