Soil acidity is one of the most common reasons for low yields of forage crops. This paper analyzes the long-term effect of liming (control -without CaO; 3 t*ha -1 CaO; 6 t*ha -1 CaO) applied to an acid soil (pHH2O 4.8) before stand establishment on the productivity of a mixture of red clover (Trifolium pratense L.) and tall oat grass (Arrhenatherum elatius L.) during the third year of production. Soil liming significantly increased hay yields in the first and second cuts by 17-25% and 46%, respectively, which resulted from an increase in the total yield and dry matter content of forage. In the third cut, soil liming had no effect on forage and hay yields due to the lower amount of precipitation in the second part of the growing season. Both lime application rates led to a significant reduction in the percentage of red clover in the first and second cuts, thus favoring the percentage of tall oat grass. In the third cut, only the percentage of weeds was lower in both lime treatments, as it decreased by more than 55% compared to the control.Keywords: forage yield, red clover, soil liming, tall oat grass Sažetak Kiselost zemljišta je jedan od najčešćih razloga za niske prinose krmnih useva. U radu je analiziran produžen uticaj primene kalcizacije (kontrola -bez CaO; 3 t*ha -1 CaO; 6 t*ha -1 CaO) na kiselom zemljištu pH 4,8, pre zasnivanja useva, na produktivnost smeše crvene deteline (Trifolium pratense L.) i francuskog ljulja (Arrhenatherum elatius L.) tokom treće godine proizvodnje. Kalcizacija zemljišta je uticala na značajno povećanje prinosa sena u prvom i drugom otkosu za 17-25%, odnosno 46% po redosledu. To je posledica povećanja ukupnog prinosa krme i sadržaja suve materije u krmi. U trećem otkosu, kalcizacija zemljišta nije ostvarila Agriculture, 2018, 19(2), p.482-489 482 uticaj na prinos krme i sena, zbog manje količine padavina u drugom delu vegetacije. Primena oba nivoa kalcizacije zemljišta je uticala na značajno smanjenje udela crvene deteline u prvom i drugom otkosu, na račun povećanja udela francuskog ljulja. U trećem otkosu je jedino udeo korova bio manji na obe varijante kalcizacije za više od 55% u odnosu na kontrolu.

The Western corn rootworm (WCR), Diabrotica virgifera sp. virgifera(Col.,Chrysomelidae), is an oligophagous pest native in America. WCR is a maizepest present in all regions of the Corn Belt. It is an invasive species which was, inEurope, first identified in Serbia, in 1992, near the Belgrade airport. The presenceof this pest in maize field can cause losses and plant damages up to 100%. A fieldexperiment was carried out in Bečej, Vojvodina province (Serbia), during 2014 and2015. In the field, 96 plants (maize cultivar NS 640), arranged in 48 pairs wereselected. Each pair consisted of one plant artificially infested with WCR eggs (Dplant) and the control plant (C plant). In both years, the experiment in the field wasregularly inspected, once a week. During each observation, the presence of "gooseneck" symptoms was recorded, and the number of plants damaged by the mostimportant stem boring and leaf feeding insects (Ostrinia nubilalis, Helicoverpaarmigera, H. zeae, aphids, mites, cicadas, etc. ) was counted. Root damages wereassessed at the end of the experiment (September), according to Ostlie and Notzel(1987), on scale 1-6. Comparing the root damages on C and D plants, less rootdamages were established on C plants. Only six i. e. four D plants had healthy roots(rate 1) during 2014 and 2015, respectively. Between D plants in 2014, the mostdamaged were14 plants, with the rate 3 (least one root chewed to within 1½ inches(3. 8 cm) of the plant). In 2015, severe damages were registered on 18 plants,which were ranked as level 6 (with three or more nodes destroyed). Only two Cplants during vegetation 2014-2015were registered with damages with rate 5 (twonodes destroyed) and rate 6 (three or more nodes destroyed), respectively.

Summary From the economic perspective, the western corn rootworm (WCR), Diabrotica virgifera sp. virgifera (Col., Chrysomelidae), poses the gravest threat to the field maize production in Serbia. The purpose of this study is to examine the impact of WCR larvae on the morphology of maize characters during a low-level artificial egg infestation. A field experiment involving the Serbian cultivar ‘NS-640’ was carried out in Bečej, Vojvodina Serbia, in 2016. In the experimental field, a total of 96 maize plants were selected, marked and arranged in 48 pairs. Each pair consisted of an infested plant (WCR eggs injected in the root zone) and an uninfested plant (distillate water injected in the root zone). The number of leaves, height and stem diameter of the plants observed were recorded. Root damage and root weight were measured and evaluated at the end of the trail. For the purpose of statistical analysis, the non-parametric Kruskal-Wallis one-way analysis of variance and a correlation matrix were used. The statistical analysis performed indicate a highly significant difference in the number of leaves and plant height between the infested and uninfested maize plants examined in July (the third field observation). During the last field inspection, significant differences were recorded only between the stem diameters of the infested and uninfested maize plants. A negative correlation was found to exist between the root damage and root weight of the plant pairs. There were positive correlations between the stem diameter, plant height and number of leaves of the infested plants, whereas positive correlations were found between the root damage and plant height of the uninfested plants.