Digitaria sanguinalis is a troublesome annual weed that causes important yield losses in different crops. Despite this, there is scarce information about different aspects of its biology under field conditions. New knowledge about the establishment process of this species will be of paramount importance in order to maximise the effectiveness of weed management. The aims of this paper were to evaluate the effect of stubble found on the surface on seed dormancy levels through the season, the effects of stubble and soyabean crop canopy on seedling emergence and to determine the field emergence pattern as a consequence of seed dormancy level at dispersal time. Seeds on the soil surface, which showed a high dormancy level at the beginning of autumn, were released from dormancy by low winter temperatures and germinated during spring as temperatures rose, showing a transient surface seedbank. Seeds covered by stubbles had delayed the emergence in the field due to lower alternating temperatures perceived by the surface seedbank. On the other hand, the presence of a soyabean crop and stubble together reduced the number of seedlings. Seeds with a high dormancy level at dispersal time showed a delayed emergence in the next season when compared with seeds with a lower dormancy level. However, the final number of seedlings was similar. Both stubble on surface and crop canopy are useful factors to lessen and delay the seedling emergence allowing the design of weed management strategies in order to diminish the population levels of this species.

中文翻译：

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马齿苋种子休眠解除和出苗受作物冠层和茬口影响

Digitaria sanguinalis 是一种麻烦的一年生杂草，会导致不同作物的重大产量损失。尽管如此，关于野外条件下其生物学不同方面的信息很少。有关该物种建立过程的新知识对于最大限度地提高杂草管理的有效性至关重要。本文的目的是评估在整个季节表面发现的茬对种子休眠水平的影响、茬和大豆作物冠层对幼苗出苗的影响，并确定田间出苗模式作为种子休眠水平的结果。散播时间。土壤表面的种子在秋初表现出较高的休眠水平，在冬季低温时解除休眠，并在春季随着气温升高而发芽，显示瞬态表面种子库。由于地表种子库感知到较低的交替温度，被残茬覆盖的种子延迟了田间的出苗。另一方面，大豆作物和残茬的存在减少了幼苗的数量。与较低休眠水平的种子相比，在传播时具有高休眠水平的种子在下一季表现出延迟的出苗。然而，最终的幼苗数量是相似的。地表残茬和作物冠层都是减少和延迟幼苗出苗的有用因素，允许设计杂草管理策略以减少该物种的种群水平。由于地表种子库感知到较低的交替温度，被残茬覆盖的种子延迟了田间的出苗。另一方面，大豆作物和残茬的存在减少了幼苗的数量。与较低休眠水平的种子相比，在传播时具有高休眠水平的种子在下一季表现出延迟的出苗。然而，最终的幼苗数量是相似的。地表残茬和作物冠层都是减少和延迟幼苗出苗的有用因素，允许设计杂草管理策略以减少该物种的种群水平。由于地表种子库感知到较低的交替温度，被残茬覆盖的种子延迟了田间的出苗。另一方面，大豆作物和残茬的存在减少了幼苗的数量。与较低休眠水平的种子相比，在传播时具有高休眠水平的种子在下一季表现出延迟的出苗。然而，最终的幼苗数量是相似的。地表残茬和作物冠层都是减少和延迟幼苗出苗的有用因素，允许设计杂草管理策略以减少该物种的种群水平。与较低休眠水平的种子相比，在传播时具有高休眠水平的种子在下一季表现出延迟的出苗。然而，最终的幼苗数量是相似的。地表残茬和作物冠层都是减少和延迟幼苗出苗的有用因素，允许设计杂草管理策略以减少该物种的种群水平。与较低休眠水平的种子相比，在传播时具有高休眠水平的种子在下一季表现出延迟的出苗。然而，最终的幼苗数量是相似的。地表残茬和作物冠层都是减少和延迟幼苗出苗的有用因素，允许设计杂草管理策略以减少该物种的种群水平。