Tillage and cover crop influence on weed pressure and Fusarium infection in spring cereals

Several studies have reported positive effect of cover crop on topsoil physical properties as well as weed suppression, but few have quantified its effect on Fusarium head blight prevention. This study explored the effect of white mustard (Sinapis alba L.) and white clover (Trifolium repens L.) as cover crops on weed pressure and Fusarium infestation in spring wheat and spring barley grain under different tillage systems. Five tillage practices were investigated in a loam soil in long term tillage experiment in Central Lithuania in Dotnuva: deep ploughing (22-24 cm), shallow ploughing (16-18 cm), shallow harrowing (8-10 cm), deep harrowing (14-16 cm) and direct drilling, with and without cover crop. Cover crops were sown using fertilizer spreader: white mustard seed were spread before harvest of the spring wheat and spring barley in 2013 and 2014, respectively and white clover - at the beginning of vegetation of winter oilseed rape in early spring, in 2017. Cover crops effect on Fusarium fungi was evaluated in spring cereals grown after the cover crop: in spring barley in 2014 and in spring wheat in 2018. Both cover crops resulted in lower weed pressure for a post - harvest period under different tillage practises. White mustard suppressed weed air-dry mass up to 90 and white clover up to 99 percent. White mustard has influenced the decrease of Fusarium graminearum contamination in spring barley grain as well as white clover reduced F. culmorum infestation level in spring wheat grain. Our results suggest that white mustard and white clover as cover crops might be an option for integrated pest management in order to supplement weed control strategy and Fusarium head blight prevention under sustainable tillage practises.