1. Effects of seedbed properties on crop emergence. 6. Requirements of crops with small seeds.
- Author
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Håkansson, Inge, Arvidsson, Johan, Etana, Ararso, Rydberg, Tomas, and Keller, Thomas
- Subjects
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SEED beds , *PLANT growth , *SEED physiology , *SOWING , *SOIL testing , *BRASSICA - Abstract
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 albaL., oilseed rape,Brassica rapaL., Metzg., sugar beet,Beta vulgarisL. and red clover,Trifolium pratenseL.) 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 pratenseL.) 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. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
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