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Research article2013Peer reviewedOpen access

Effects of seedbed properties on crop emergence. 6. Requirements of crops with small seeds

Håkansson, Inge; Arvidsson, Johan; Etana, Ararso; Rydberg, Tomas; Keller, Thomas


The effects of seedbed properties on emergence of various crops were studied in a series of experiments. Results for crops with seeds weighing <7 mg are reported here. The experiments were carried out in shallow plastic boxes placed directly on the ground in the field. Small seeds require shallow sowing, which is a great disadvantage in the event of dry weather after sowing, particularly on clay and clay loam soils, where the upper 3-cm soil layer quickly dries to wilting point. Nevertheless, good emergence of crops with seeds weighing 2-7 mg (white mustard, Sinapis alba L., oilseed rape, Brassica rapa L., Metzg., sugar beet, Beta vulgaris L. and red clover, Trifolium pratense L.) was often obtained when the seed was placed at about 3-cm depth directly on a firm basal layer with >6% plant-available water and covered by soil dominated by aggregates <5 mm. Cruciferous crops germinated most rapidly, which facilitated emergence from shallow depth. Sowing could be slightly shallower in coarse-textured than in fine-textured soils, since the former soils dry less rapidly to below wilting point. For timothy (Phleum pratense L.) with seeds weighing about 0.5 mg and requiring a sowing depth <2.5 cm, it was impossible to design a seedbed that eliminated the risk of poor emergence in dry weather. Firming of the seedbed after sowing favoured emergence only in initially dry seedbeds. The risk of poor emergence because of surface layer hardening was minimised by placing seeds at a depth and in seedbed conditions that promoted the fastest possible emergence.


compaction; dry weather; germination; oilseed rape (Brassica rapa L., Metzg.); red clover (Trifolium pratense L.); sowing depth; sugar beet (Beta vulgaris L.); surface layer hardening; white mustard (Sinapis alba L.)

Published in

Acta Agriculturae Scandinavica, Section B - Soil and Plant Science
2013, Volume: 63, number: 6, pages: 554-563