How soil-applied maltodextrin with caraway (Carum carvi L.) oil affects weed and soil microbiological activity in maize (Zea mays L.) stands

Abstract

The essential oil (EO) of caraway (Carum carvi L.) is a confirmed source of herbicidal compounds. Therefore, the object of this study was to determine the effect of soil-applied maltodextrin (MD) microcapsules containing approximately 12% caraway EO on weed infestation in maize (Zea mays) stands, the yield of maize and the number of colonies of soil microbes. A two-year field experiment was set up in a randomized block design on brown podzolic soil. It was shown that the MD-EO microcapsules affected the number of only some annual weeds, such as G. quadriradiata, G. parviflora, and E. crus-galli. The dry mass of monocotyledonous and dicotyledonous weeds was significantly reduced by all the MD treatments, on average by 45-65% and 35-65%, respectively, compared to the control. The number of maize plants and cobs per 1 m2 was reduced by 17% and 21%, respectively, following the MD-EO treatments. The mass of the cobs was unaffected by the MD-EO treatments. The application of MD-EO caused a significant decrease in the number of soil mesophilic bacteria colonies but did not affect the amounts of phenolic compounds in the soil. In conclusion, the soil application of caraway EO within MD microcapsules has a potential as a natural weed control agent but should be studied further to optimize its dose and timing of application for weed control in maize stands.