[Development of the organic soil substance and yield formation of winter wheat in different farming systems at a silty sand soil]

abonos nitrogenados amendement du sol analyse de sol biologie du sol brandenbourg brandenburg brandenburgo crop yield cropping patterns cropping systems cultivos de invierno culture d'hiver enmiendas del suelo ferme pilote fertilidad del suelo fertilisation fertilizer application fincas experimentales humus nitrogen fertilizers organic matter pilot farms plan de culture rendement des cultures rendimiento de cultivos sandy soils sistemas de cultivo soil amendments soil biology soil fertility soil testing soil treatment sol sableux suelo arenoso textural soil types tipos texturales de suelos traitement du sol tratamiento del suelo triticum type de sol textural winter crops