Integrated effects of herbicides and foliar fertilizer on corn inbred line

ABSTRACT Plant response to herbicides is one of the most essential points in corn (Zea mays L.) production, especially in inbred lines. Weed abundance is higher in corn lines comparing to hybrids. Insufficient herbicide selectivity in lines crop can be a limiting factor for their application. Weed control today is based on Integrated Weed Management (IWM) approach, i.e. to use all possible methods and measures for weed control and better crop fitness. In this research, sensitivity of one corn inbred line (selection based on previous research) was tested to two sulfonylurea herbicides in treatments with and without foliar fertilizer. Treatments included recommended and double field doses and control (no herbicide), with and without foliar fertilizer. Herbicides and foliar fertilizer were applied as a mixture. In a 3 yr field experiment, herbicides expressed different selectivity to the tested line. The line was further tested in controlled conditions for dose-response analyses in order to determine variations in biomass and biochemical compounds levels. The double dose of foramsulfuron affected fresh matter significantly (p < 0.05) with 90% decrease, compared to control. An experiment in controlled conditions showed increased tolerance to herbicides in treatments with foliar fertilizer - according to higher effective doses (ED10, ED50, and ED90) estimated, indicating higher plant tolerance to herbicides when foliar fertilizer was applied. In corn leaves the highest herbicide dose and foliar fertilizer induced slight reduction of concentrations of free thiol groups, soluble proteins and phytic P (to 14.1%, 9.3% and 9.9%, respectively) and increased phenolics concentration (up to 26.7%) compared to treatment without herbicide application. Obtained results indicate positive effects of foliar fertilizer when it is applied in mixture with herbicides, and foliar fertilizing should be considered as important strategy in obtaining higher yields.