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Effect of water-injection and seed-soaking on establishment of sunflower in a vertisol

R. Ferraris

CSIRO Division of Tropical Crops and Pastures, St. Lucia QLD 4067

Poor establishment and associated low yield of summer crops are problems in the self-mulching Vertisols of tropical and sub-tropical Australia (1). Water-injection and seed-soaking are two techniques with potential for improving establishment.

Methods

Site details: Mywybilla black earth, Typic Pellustert, at Dalby. Species: sunflower, Helianthus annuus, cv. Hysun 33. Sowing: 7 cm depth, 10 or 14 seeds/m, tilled seedbed, six dates. Treatments: dry or soaked seed; sown dry or with water injection. Method: soak until early splitting of testa, air dry, recoat with Thiram. Water injection into sowing furrow at 75 mL/m. Plots: rows 20 m long. Datum area: five 2 m of row quadrats/plot. Design: randomised block, three or four replicates. Measurements: emergence counts three times per week per quadrat. Post-sowing soil water content (SWC) to seed depth. Minimum soil temperature at seed depth

(T 1-4 days after sowing).

Results and discussion

Water injection hastened emergence and promoted establishment on two occasions, 12 February 1987, 14 October 1987, (Table 1). Seed soaking had no effect on rate of emergence and its effect on establishment was inconsistent. Responses to injection or soaking did not appear to be associated with seedbed temperature or mean water content. Neither technique can be recommended for routine sowing.

Table 1. Effect of sowing method and seed treatment on days to 50% emergence and establishment of sunflower (%).

Acknowledgment

These studies were part of a project funded by the Rural Credits Development Fund.

References

Spackman, G.B. 1987. Aust. Inst. Agric. Sci., Brisbane, Occas. Paper 34, 130-135.

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