Influence of Threading of Grazing Cattle on Pasture Soil Compaction

Abstract

The aim of the performed investigations was to establish the influence of longterm threading of neat cattle and sheep during intensive grazing on compaction of noncarbonate, smonitza-like meadow black soils in the Kolubara river valley. To achieve the set task, six soil profiles were opened under similar relief conditions. Three of the profiles originated from a plot which has been, according to the statement of its owner, more than 20 years used as grazing land, and the other 3 profiles were opened at a nearby site under natural forest vegetation, comprised of common oak and common ash (As. Querceto-Fraxinetum serbicum, Rud.) with a well developed grass cover in the ground layer. The profiles under forest vegetation served as comparative (virgin) soils. Bulk density of the soils in the surface (0-10 cm and 10-20 cm) layers of the humus horizon of the meadow black soil under grazing land increased significantly (p<0.05) due to the grazing, by 0.29 Mg m-3 in the layer between 0 and 10 cm, and by 0.13 Mg m-3, in the layer between 10 and 20 cm, in comparison with the forest black soil. At the same time, this caused a significant decrease of total porosity, macroporosity and hydraulic conductance. Total porosity of the meadow black soil under grazing land was decreased by about 10% in the layer between 0 and 10 cm, and about 4% in the layer between 10 and 20 cm. In the surface layer (0-20 cm) of the humus horizon of the grazing land macroporosity is about two times lower than in the forest. Macroporosity of the humus horizon of the grazing land is very low and varies between 2.9 and 7.8% vol. Saturated hydraulic conductivity in the humus horizon (0-30 cm) of the grazing land is significantly lower (8-10 mm h-1) than in the forest (115-285 mm h-1). The investigated physical characteristics of meadow black soil under grazing land do not yield favourable conditions for normal development and health of crops.

Cilj istraživanja bio je utvrđivanje uticaja posledica višegodišnjeg gaženja krava i ovaca, u toku intenzivne ispaši na zbijanje beskarbonatnih, smoničavih livadskih crnica (semigleja) u dolini reke Kolubare. Za realizaciju tog cilja otvoreno je 6 zemljišnih profila u sličnim reljefskim uslovima, i to: 3 profila na parceli koja se, po izjavi njenog vlasnika, preko 20 godina koristi kao pašnjak, a druga 3 profila iskopana su na bliskom rastojanju pod prirodnom šumskom vegetacijom, koju čini zajednica hrasta lužnjaka i poljskog jasena (As. Querceto–Fraxinetum serbicum, Rud.) sa dobro razvijenim prizemnim travnim pokrivačem. Profili pod šumskom vegetacijom poslužili su kao uporedna (devičanska) zemljišta. Rezultati ovih ispitivanja pokazali su da je se pod uticajem ispaše zapreminska masa (gustina) zemljišta značajno (P<0.05) povećala u površinskom delu profila (na dubinama od 0 do 10 i 10-20 cm), i to za 0.29 Mg m-3, na dubini od 0-10 cm, i za 0.13 Mg m-3, na dubini 10-20 cm, u poređenju sa livadskom crnicom pod šumom. To je istovremeno imalo za posledicu i znatno smanjenje ukupne poroznosti, makroporoznosti i hidrauličke provodljivosti. Ukupna poroznost livadske crnice pod pašnjakom smanjena je za oko 10% na dubini od 0 do 10 cm, odnosno, oko 4% na dubini 10-20 cm. U površinskom delu (0-20 cm) humusnog horizonta pašnjaka makroporoznost je za oko dva puta manja nego u šumi. Makroporoznost humusnog horizonta pašnjaka je veoma mala i varira od 2.9 do 7.8% zapreminskih. Saturisani hidraulički konduktivitet u humusnom horizontu (0-30 cm) pašnjaka je mnogo manji (8-10 mm h-1) nego u šumi (115-285 mm h-1). Na osnovu rezultata ovih istraživanja može se zaključiti da fizičke osobine livadske crnice pod pašnjakom ne pružaju povoljne uslove za normalni porast i zdravlje biljaka.