Reduced cultivations and straw disposal systems with spring cereals on various soil types. I. Yields and weed incidence [couch grass]

aradura avenas avoine barley cebada cero-labranza clay soils harrowing hersage labour limpia de rastrojos loam soils malezas mauvaise herbe oats orge paille paja ploughing rastreo silty soils sol argileux sol limoneux sol sablolimoneux straw stubble cleaning suelo arcilloso suelo franco suelo limoso weeds