VARIABILITY OF PASTURES BASED ON SOIL QUALITY

The study evaluated the spatial variability of pastures, in the area of Sanpetru Mare, Timis County, Romania. The analyzed area included 80 plots in six size categories in relation to the surface: 0.01-1.0 ha (25 plots), 1.01-2.0 ha (21 plots), 2.01-5.0 ha (19 plots), 5.01-25.0 ha (5 plots), 25.01-50.0 ha (6 plots), and 50.01-100.0 ha (4 plots). Soil pH, humus (H, %), phosphorus (P, ppm), and potassium (K, ppm) were determined, and the values for V (%) and NI (%) were calculated. The series of values presented normal distribution (r=0.854 for pH, r=0.956 for P, r=0.986 for K and r=0.829 for H). Very strong correlation was recorded between pH and V (r=0.962) and between NI and H (r=0.969), p<0.001. Strong correlation was recorded between NI and pH (r=0.838), p<0.001) and moderate correlations between H and pH (r=0.757) and between NI and H (r=0.748), p<0.001. Based on PCA, PC1 explained 62.723% of variance, and PC2 23.247% of variance, in relation to pH, H, P and K, as soil quality indices. Spline models described pH and H content variation in relation to the plots size category (Psc), under statistical safety conditions (epsilon = 2.0722 E- 05 ; epsilon = 6.06 E- 05).