Aggregate composition and stability of structural aggregates in humus horizons of forest
2006
Gajic, B.(Faculty of Agriculture, Belgrade - Zemun (Serbia). Institute of Land Management) | Zivkovic, M.(Faculty of Agriculture, Belgrade - Zemun (Serbia). Institute of Land Management)
The present study includes the results of comparative investigations of aggregate composition and water stability of structural aggregates in humus horizons of calcareous rendzina, Eastern Serbia, under native forest and pasture vegetations and the same rendzina utilized long-term as arable field. The results show that aggregate composition and water stability of structural aggregates in the cultivated calcareous rendzina are significantly impaired due to a long-term anthropogenization. In the cultivated rendzina, the content of agronomically most valuable aggregates (0.25-10 mm) is decreased, while the percentage of cloddy aggregates (greater than 10 mm) is increased about 1.5 to 2 times in comparison with the forest and pasture. The forest and the permanent pasture calcareous rendzina had a greater aggregate water stibility than the cultivated rendzina in humus horizon. The lowest water stability is found in aggregates greater than 3mm. The largest mean weight diameters (MWD) of dry aggregates were found in forest calcareous rendzina (4.48 mm, vs. 4.23 mm in pasture and 3.98 mm in arable field). MWD of water stable aggregates was higher in pasture (1.32 mm) and forest (1.12 mm) than in cultivated calcareous rendzina (0.54 mm). The structure coefficient of cultivated calcareous rendzina was lower than in forest and meadow.
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