Crop diversity, crop structures and crop residue can modify the seed-bank environment, influencing the seedling emergence of some weeds. The objectives of this work were to analyse (1) the effect of winter crop canopies of canola and wheat and soybean stubble on seedling emergence of Conyza sumatrensis and Raphanus sativus and (2) the effect of different soybean crop structures and soybean stubble on Digitaria insularis and Amaranthus palmeri seedling emergence. Two different field experiments were conducted at Buenos Aires University in a completely randomised factorial design with five replicates. The two winter species showed differences in the emergence timing whereas the two summer species emerged at the same time but with differences between years. Seedling emergence of A. palmeri was reduced by the presence of crop residue while the effect on C. sumatrensis and R. sativus emergence were more variable between years and D. insularis was not affected. Crops did not affect seedling emergence of winter species or that of A. palmeri. However, D. insularis emergence was favoured by soybean presence, mainly with closer canopy structures. Management decisions that promote the presence of crop residues favour the reduction of seedling emergence of palmer amaranth. In contrast, evaluated crop plant densities and planting dates were not able to reduce the seedling emergence of C. sumatrensis, R. sativus and D. insularis. Planting soybean in more competitive crop structures with closer canopies is not a good option due to the improvement of seedling emergence of D. insularis. Crop management decisions that inhibit seedling emergence in some species could stimulate it in others.

作物多样性、作物结构和作物残茬可以改变种子库环境，影响一些杂草的出苗。本工作的目的是分析 (1) 双低油菜、小麦和大豆茬冬季作物冠层对Conyza sumatrensis和Raphanus sativus出苗的影响，以及 (2) 不同大豆作物结构和大豆茬对Digitaria insularis 的影响和苋菜幼苗出苗。在布宜诺斯艾利斯大学进行了两个不同的田间试验，采用完全随机的因子设计，重复五次。两个冬季物种的出现时间不同，而两个夏季物种的出现时间不同，但年份不同。A. palmeri 的幼苗出苗因作物残留物的存在而减少，而对C. sumatrensis和R. sativus出苗的影响在年份之间变化更大，而D. insularis未受影响。作物不影响冬季物种或A. palmeri 的幼苗出苗。然而，D. insularis大豆的出现有利于出苗，主要是冠层结构更紧密。促进作物残留物存在的管理决策有利于减少苋菜苗的出苗。相比之下，评估的作物植物密度和种植日期不能减少C. sumatrensis、R. sativus和D. insularis的幼苗出现。由于D. insularis幼苗出苗的改善，将大豆种植在具有更紧密冠层的更具竞争力的作物结构中并不是一个好的选择。抑制某些物种出苗的作物管理决策可能会刺激其他物种的出苗。