The effect of cultivation on the vertical distribution of seeds in the soil.
In a study on the distribution of weed seeds in soil, seeds of lucerne and oilseed flax, which differ markedly in size, shape and seed-coat properties, were sown on the soil surface and the land was ploughed twice in different directions to a depth of 20 cm, then disk. harrowed several times. The percentage of seed recovered from soil samples was 51% for flax and 24% for lucerne. The number of seeds per unit volume increased with depth down to 20 cm.-R.B.