Verica Vasic

Application of pre-emergence herbicides in poplar nursery production

In addition to pests and diseases, weeds are a major problem in poplar nursery production. The possibilities of herbicide application in juvenile poplar growth were researched, taking into account that weeds are one of the main limiting factors. The following pre-emergence herbicides were tested: acetochlor, S-metolachlor, metribuzin, oxifluorfen, and dimethenamid during two vegetation seasons at two locations, which differed by the soil physico-chemical characteristics. The study results show that the number of weeds on sample plots was significantly reduced by the tested herbicides when compared to control plots. The highest reduction in the number of weeds was achieved using the herbicides acetochlor and metribuzin. However, metribuzin showed a phytotoxic effect on sandy soil. Metribuzin application is recommended only on the soils with higher contents of organic matter, where the phytotoxic effect was absent. Acetochlor, S-metolachlor, oxifluorfen, and dimethenamid were not phytotoxic to poplars and can be used for weed suppression in the production of poplar plants.

Weeds in Forestry and Possibilities of Their Control

However, all weeds do not have equal significance. When considering weed control attibutes, perennial weeds present are far greater challange due to difficulties employing mechanical means, because perennials are often stimulated to grow and disperse even more intensively. Perennial weed species, such as Sorghum halepense, Convolvulus arvensis, and Cynodon dactylon, have well-developed underground organs and are great problems not only in agriculture, but also in nursery production of forest planting materials.

Ecological characteristics and the remediation potentials of opencast mines at Celarevo and Sajkas brickyards, Vojvodina, Serbia

Introduction In the Vojvodina province, Northern Serbia, the consequences of soil degradation, damage and devastation are increasingly explicit. The negative processes lead to a significant decrease of the area of farmland, forest and various forms of protected natural parks. An especially endangered soil type is chernozem, the highly productive agricultural soil which occupies approximately 45% of the area of Vojvodina (Živković et al., 1972). The impacts of different processes of degradation, damage, and finally the devastation of the most productive soils are multiple. Unfortunately, the consequences of the adverse effects cannot always be adequately mitigated, i.e. eliminated. One of the most frequent way of soil degradation in Vojvodina is raw material exploitation in many brickyards (Miljković et al., 2001). In this way, in addition to soil damage, a thick layer of parent matherial on which the soil was originally formed, is permanently lost. Raw material exploitation causes the changes of the relief, hydrological, ecological and site conditions in general. The spontaneous soil renewal in the opencast mines of brickyards is a slow process which results in soil formation with the significantly poorer productive properties. Therefore, such areas should be subjected to the adequate rehabilitation procedures. This study presents the complex analyses of the present environmental status and proposes the sustainable rehabilitation methods of the birckyard opencast mines at Čelarevo and Šajkaš.