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\udgrowth and yielding. Its combinination with other cropping measures can ensure optimal\udcrop density for maximal growth and photosynthesis efficiency. The aim of this study\udwas to investigate the influence of different cropping systems: monoculture and two rotations,\udincluding maize, wheat and soybean (MSW and MWS), and different weed management\udmethods (weed removal by hoeing, application of a full recommended herbicide\uddose (RD) and half that dose (0.5 RD), and weedy check) on weed biomass and maize\udgrowth parameters - leaf area index (LAI), free energy, contents of chlorophyll and carotenoids,\udgrain yield, and their possible relationships in two fields of the maize hybrids ZP 677\ud(H1) and ZP 606 (H2).\udThe lowest LAI and grain yield were found in monoculture, particularly in weedy\udcheck, which had relatively high weed infestation. Higher weed biomass was also\udobserved in herbicide treated plots in monoculture. Such high competition pressure\udindicates a stress reflected on reduced LAI and chlorophyll content, and increased free\udenergy and content of carotenoids. On the other hand, rotation, particularly if it is combined\udwith the application of herbicides or hoeing, had a positive impact on yielding\udpotential by increasing LAI and the contents of chlorophyll and carotenoids, and decreasing\udfree energy