Dusan Kovacevic

Effects of different cropping systems and weed management methods on free energy and content of pigments in maize

Rotation is a cropping system that has many advantages and ensures better crop growth and yielding. Its combinination with other cropping measures can ensure optimal crop density for maximal growth and photosynthesis efficiency. The aim of this study was to investigate the influence of different cropping systems: monoculture and two rotations, including maize, wheat and soybean (MSW and MWS), and different weed management methods (weed removal by hoeing, application of a full recommended herbicide dose (RD) and half that dose (0.5 RD), and weedy check) on weed biomass and maize growth parameters - leaf area index (LAI), free energy, contents of chlorophyll and carotenoids, grain yield, and their possible relationships in two fields of the maize hybrids ZP 677 (H1) and ZP 606 (H2). The lowest LAI and grain yield were found in monoculture, particularly in weedy check, which had relatively high weed infestation. Higher weed biomass was also observed in herbicide treated plots in monoculture. Such high competition pressure indicates a stress reflected on reduced LAI and chlorophyll content, and increased free energy and content of carotenoids. On the other hand, rotation, particularly if it is combined with the application of herbicides or hoeing, had a positive impact on yielding potential by increasing LAI and the contents of chlorophyll and carotenoids, and decreasing free energy. [Projekat Ministarstva nauke Republike Srbije, br. TR-31037]

Research results of long-term use of new line of machines and tools for land surface and depth arrangement

This paper presents the results of the application of the machines and tools for new technologies in plant production for two years of research. The comparative analysis of the influence of new technologies and new types of machines was done, and also the effect of conventional tillage systems on several agricultural crops (sunflower, commercial maize and wheat). During the experiment, we analyzed the effects of application of new line of machines to: physical properties of soil, morphological features of crops, use of energy and yield, and we also analyzed the economic aspects of the application. On the control plots, a conventional tillage system was simultaneously applied for comparative analysis of the previously mentioned factors. Trials were conducted on production plots of Maize Research Institute “Zemun Polje” in Krnjesevci from October 2008 until July 2010.

Effect of Fertilizers on the Yield of Alternative Small Grains

Summary The purpose of this study is to evaluate the effect of organic farming technologies on the yield of alternative types of wheat: hard wheat (Triticum durum), spelt (Triticum aestivum ssp. spelta) and a common variety of (soft) winter wheat (Triticum aestivum ssp. vulgare). The experiment was carried out during 2010-11 and 2011-12, at the Radmilovac experimental field of the Faculty of Agriculture in Belgrade, according to the randomized block design in four replications. In addition to the control treatment (without fertilizers), microbiological fertilizers were applied in topdressing (alone) and in combination with organic fertilizer before sowing. Crops were grown under a four-crop rotation on leached chernozem in the rainfed water regime. The average yields of the varieties examined were not significantly different depending on the growing year, whereas fertilization showed a highly significant effect on the grain yield. The combined application of microbiological and organic fertilizers resulted in the highest yields in both years (5,209 and 4,992 kg ha-1, respectively). The selected wheat varieties exhibited different responses to the treatments applied. The highest yield was observed in the common soft wheat variety examined (5,170 and 5,611 kg ha-1), whereas the lowest in durum wheat (3,138 and 2,429 kg ha-1). The analysis of experimental factor interactions showed that statistically significant effects on the yield could be attributed to the year-fertilization interaction. The wheat yields obtained are similar to those observed in the conventional production system due to favorable weather conditions and a proper selection of the type and sequence of crops that are part of the four-crop rotation (winter wheat, maize, spring barley + red clover, and red clover).