engleski

Lysimetric Researches on Pseudogley in a Forst of Pedunculate Oak and Common Hornbeam in the Region of Northwestern Croatia

Lysimetric research of forest ecosystems in Croatia started only 4 years ago. Scarce data on the concentration of heavy metals in lysimetric liquids do not provide us with adequate insight into the state and processes that take place in the pedosphere under the forest stands. Eighteen lysimetres were set up on nine experimental plots in a forest of pedunculate oak and common hornbeam (Carpino betuli-Quercetum roboris Anić 1959/emed. Rauš 1969). The lysimeters were installed at depths of 10 cm, i.e. under the humus accumulative horizon and 100 cm, i.e. in the mineral part of the soil. The soil type is pseudogley of level terrains, medium deep and occurs in the aforementioned forest community in 86% of cases. By its mechanical composition it belongs to the light clays and clayed loams. In the surface horizons (Aoh. Bg) the soil shows a very acid reaction (pH 4, 6-5, 2). In deeper layers, it shows a neutral to alkaline reaction (pH 6, 8-7, 3). According to the humus content in the humus-accumulative horizon it belongs to the category of highly humous soil. With regard to the supply with accessible phosphorus and potassium, the supply is moderately good to good in Aoh horizon and poor in the lower layers of soil. The lysimetric investigation covered stands of 18 to 140 years old. Lysimetric liquids were sampled once a month and the amount of pH were also measured. Following soil stabilization of 2 years the content of heavy, metals in lysimetric liquids (Cd, Pb, Cu and Zn) was determined. On the plots samples of rainwater were collected by rain-gauges installed under the tree crowns: the liquid that ran down the stem of oak and hormbeam tress (stemflow) was collected. For controls the liquid collected in raingauges, installed outside the stand, was used. In lysimetric liquids an increased amount of lead and cadmium was recorded. An average content of cadmium in lysimetred at 10 cm depth was 0, 178 ng/l, lead 39, 0 ng/l, copper 5, 0 ng/l, zinc 9, 9 ng/l. In lysimeters at the depth of 100 cm an average cadmium content amounted to 0, 168 ng/l, lead 37, 7 ng/l, copper 3, 3 ng/l and cadmium 0, 9 ng/l of lead, 1, 9 ng/l of copper and 5, 2 ng/l zinc. The liquid collected in forest stands had a slightly increased content of heavy metals compared to the controls.

pseudogley; pedunculate oak; lysimeters; heavy metals

nije evidentirano