Spatial variability of texture and coarse fragment content in eutric brown soils on flysch rocks at the level of an olive tree

V diplomski nalogi nas je zanimala variabilnost fizikalnih lastnosti evtričnih rjavih tal na flišnih kamninah, ki so lahko zelo spremenljiva zaradi kombinacije laporovcev in peščenjakov, ki se razlikujejo po hitrosti preperevanja. Diplomska naloga je del projekta KOREOLJKA (ŠIPK). Terensko delo in vzorčenje smo izvedli v oljčniku na Škofijah. Določali smo vsebnost skeleta v tleh, teksturo in vodo zadrževalne lastnosti tal. Tla so vsebovala v povprečju 5,5 % skeleta. Analizo teksture smo opravili s sedimentacijsko metodo, brez predhodnega odstranjevanja organske mase in karbonatov, s katero smo določili, da se večina vzorcev uvršča v teksturni razred GI. Frakcija peska je bila najbolj variabilna in je naraščala z globino. Ugotovili smo, da skupna variabilnost teksture presega variabilnost analitske metode pri vseh frakcijah, razen pri glini na globini 30 cm. V skladu s postavljeno hipotezo večjo prostorsko variabilnost izkazuje skelet v primerjavi s teksturo. Vodo zadrževalne lastnosti smo analizirali na štirih vzorcih in ugotovili, da lahko obravnavana tla do globine 1 m zadržijo 145 mm rastlinam dostopne vode. Heterogenost tal lahko pripišemo različno hitremu preperevanju tal na flišnih kamninah in terasiranju ter rigolanju obravnavanega območja.In the thesis we were interested in the variability of the physical properties of eutric brown soils on flysch rocks, which can be very variable due to the combination of marls and sandstones, which differ in the rate of weathering. The graduation thesis is part of the KOREOLJKA (ŠIPK) project. Field work and sampling were performed in the olive grove in Škofije. We determined the coarse fragment content in the soil, the texture and water retention properties of the soil. The soil contained an average 5.5 % of coarse fragment. Texture analysis was performed by the sedimentation method, without prior removal of organic matter and carbonates, which determined that most of the samples fall into the GI texture class. The sand fraction was the most variable and increased with depth. We found that the total texture variability exceeds the variability of the analytical method in all fractions except clay at a depth of 30 cm. According to the hypothesis, the coarse fragment shows greater spatial variability compared to the texture. Water retention properties were analyzed on 4 samples and it was found that the considered soil depth of 1 m can retain 145 mm of water accessible to plants. The heterogeneity of the soil can be attributed to the differently rapid weathering of the soil on the flysch rocks and the terracing and plowing of the sample area