Long-term effects of primary tillage on above-ground weed flora and on the weed seedbank

aradura banco de semillas del suelo barley cebada chemical control cultivation cultivo cultivo mixto depth distribution spatiale dynamique des populations emergence emergencia escarda galium graine herbicidas herbicide herbicides hordeum vulgare integrated control labiatae labour lamium purpureum lucha integrada lutte chimique lutte physique malezas mauvaise herbe mixed cropping orge physical control ploughing population dynamics pratique culturale profondeur profundidad seeds semilla soil morphological features soil seed banks spatial distribution stock semencier du sol trait morphologique du sol weed control weeds