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Verano stylo seed production in the douglas daly district, northern territory, Australia

M.R. Norton, N.L. Thomas and P.C. Shotton

Department of Primary Industry and Fisheries, PO Box 79 Berrimah NT 0828

There is increasing interest in pasture seed production in the Douglas Daly agricultural district (13S, 131E). The objectives of this work were to assess the potential for seed production of Verano stylo, Stylosanthes hamata, in the district and to determine the correct timing for direct heading and suction harvesting.

Methods

A uniform area from a commercial, unirrigated crop was selected and divided into four blocks each being randomly subdivided into 11 plots harvested at intervals between 10 May and 8 August. A method of sequential sampling was used (1). Rainfall for the year under study (1989) was 1208 mm, being marginally above the annual average of 1144 mm.

Results and discussion

Seed yield standing in the crop available for direct heading peaked at harvest 3 (H3, 7 June, day 158 of year) with 483 kg/ha and then fell rapidly so that at H4 (14 June, day 165) only 159 kg/ ha was present. This indicated that a single week's delay resulted in a yield reduction of 67%. A more gradual yield decline was evident thereafter. There was an abrupt end to the wet season which probably contributed to the uniformity of flowering and the rapid onset of dry conditions hastened seed maturation and also contributed to the marked seed shedding observed.

Figure 1. Changes in standing, fallen and total seed yield of Verano stylo.

Yield of fallen seed (from suction harvest) peaked at H7 (5 July, day 186) with 903 kg/ha, remaining at a similar level until H10, (26 July, day 207). Suction harvesting permits access to greater yield for a longer period than direct heading.

Reference

Loch, D.S., Hopkinson, J.M. and English, B.H. 1976. Aust. J. Exp. Agric. Anim. Husb. 15, 218-255.

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