Weed infestation of cereals in organic, conventional and intensive farms in Malopolska region [Poland]

agriculture biologique agriculture intensive cereal crops chambre de croissance cultivos de cereales especies experimentation exploitation agricole explotaciones agrarias farming systems farms fitotrones germinability graine growth chambers infestation intensive farming malezas mauvaise herbe organic agriculture plantule poder germinativo poland pologne polonia sampling seedlings seeds semilla silty soils soil sol sol limoneux species statistical methods suelo suelo limoso weeds