The changes of weed-crop competition between wild mustard and important crop species under the future climate and ozone treatment

Abstract

Climate change, manifesting by increasing atmospheric CO2 concentration and air temperature induces planty of changes in crop physiology. Moreover, climate change interacts with other biotic and abiotic environmental stress factors, leading to complex shift in crops growth and productivity in the future. Therefore the aim of this study was to investigate the changes in growth and competitiveness of important crop species in response to competition with wild mustard under ozone pollution and climate change. Spring barley (Hordeum vulgare L.), pea (Pisum sativum) and summer rape (Brassica napus L.) were grown in mono- and mixed-cultures with wild mustard (Sinapis arvensis) under current climate (CC) (400 μmol mol−1 of CO2, 21/14 ºC day/night temperature) or future climate (FC) conditions (800 μmol mol−1 of CO2, 25/18 ºC day/night temperature) with and without O3 treatment (+O3) (180 μg m-3). Dry biomass of roots and shoots, as well as leaf area (LA) were investigated. Weed suppression capacity (WSC) – an ability to reduce weed growth at competition, was calculated as the ratio of dry biomass of wild mustard grown in monoculture and in competition with corresponding crop. The presence of wild mustard reduced shoot dry weight of barley and pea (27% and 34%, respectively, p<0,05) at current climate. Ozone pollution hardly affected above ground biomass of investigated crop species grown in monocultures; however, weed-induced shoot biomass losses reduced in barley and pea at CC+O3 conditions. Rape’s shoot biomass was unaffected by weed competition, irrespective of O3 treatment. FC stimulated monoculture crops growth, however, increased negative weed effect on shoot growth of barley and rapes. Moreover, FC+O3 conditions further increased weed-induced biomass losses in these crop species: shoot biomass was reduced by 40% and 33% in mixed-culture as compared to monoculture barley and rape.[...]