Horizontal movement of seeds following tine and plough cultivation: implications for spatial dynamics of weed infestations

Horizontal movement of seeds by different cultivators was investigated in three experiments. Seeds of barley (Hordeum vulgare L.), field bean (Vicia faba L.) and oilseed rape (Brassica napus L.) were positioned on the soil surface or buried 0.1 m deep prior to cultivation. Seed movement was assessed by counting germinated seedlings. The type of tine implement used significantly affected mean seed movement, with surface-sown seeds bring moved significantly further than buried seeds. Primary cultivation with flexi- or spring-tine machines moved seeds further than straight-tine or power harrow implements. However, there was no overall difference between plough and flexi-tine mean seed movement. A single pass with a tine attached to a seed drill moved seeds less than the two passes with tine plus seed drill, but the first pass had the greatest effect. Small oilseed rape seeds moved significantly further than larger barley or field bean seeds. More than 84% of seeds moved less than or equal to 1 m from the source; no seeds were observed >4.8 m in a forward direction or >0.2 m backwards from the source. In a fourth experiment, plots containing seeds of Sinapis arvensis L. were cultivated in alternate directions in successive years. The results broadly validated the findings of the previous experiments. Quantifying the horizontal movement of weed seeds is important to the understanding of the spatial dynamics of weed patches and thus in the prediction of future weed distributions.