Benefits of the Phytotoxic Ozone Dose (POD) index in dose-response functions for wheat yield loss

The effects of delaying chemical fallowing in a pasture rotation on pasture quality and subsequent wheat yield were investigated at sites near Minyip and Charlton, Victoria, in 1983 and 1984. Three chemical fallows were commenced at different times and were compared with a conventionally cultivated fallow. The earliest chemical fallow was established, together with a conventional fallow, at the end of winter. The second chemical fallow commenced towards the end of the rapid spring growth period in mid-October (early hayfreezing), and the third in mid- November (late hayfreezing) on a grass-dominant pasture. The pasture in spring ranged from 51 to 72% digestible dry matter (DDM) but the quality declined to 42-50% DDM by the end of the fallow treatments in autumn at each site in both years. Weathering of the pasture over summer reduced it to roughage. In contrast to a conventional fallow, early hayfreezing of pasture reduced the yield of subsequent wheat crops at Minyip by 14% in 1984 and 26% in 1985. Late hayfreezing caused losses of around 35% in each year at Minyip. At Charlton yield losses were much lower with only 14% loss observed from late hayfreezing in 1985. Because the feed produced by hayfreezing was of very poor quality, hayfreezing cannot be recommended as a viable fodder conservation method as it could not adequately compensate for any yield loss.

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On the statistical evaluation of dose-response functions

Radiation and Environmental Biophysics ◽

10.1007/bf01323095 ◽

1974 ◽

Vol 11 (1) ◽

pp. 1-13 ◽

Cited By ~ 29

Author(s):

A. M. Kellerer ◽

J. Brenot

Keyword(s):

Dose Response ◽

Statistical Evaluation ◽

Response Functions

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Improvement of the ISO classification system based on dose-response functions describing the corrosivity of outdoor atmospheres

Outdoor Atmospheric Corrosion ◽

10.1520/stp10884s ◽

2009 ◽

pp. 73-73-15 ◽

Cited By ~ 6

Author(s):

J Tidblad ◽

V Kucera ◽

AA Mikhailov ◽

D Knotkova

Keyword(s):

Dose Response ◽

Classification System ◽

Response Functions

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Downy Brome (Bromus tectorum) Interference and Economic Thresholds in Winter Wheat (Triticum aestivum)

Weed Science ◽

10.1017/s0043174500056447 ◽

1990 ◽

Vol 38 (3) ◽

pp. 224-228 ◽

Cited By ~ 40

Author(s):

Phillip W. Stahlman ◽

Stephen D. Miller

Keyword(s):

Winter Wheat ◽

Bromus Tectorum ◽

Yield Loss ◽

Wheat Yield ◽

Dry Weight ◽

Quadratic Equation ◽

Downy Brome ◽

Economic Threshold ◽

Weed Density ◽

Economic Thresholds

Densities up to 100 downy brome m2were established in winter wheat in southeastern Wyoming and west-central Kansas to quantify wheat yield loss from downy brome interference and to approximate economic threshold levels. A quadratic equation best described wheat yield loss as a function of weed density when downy brome emerged within 14 days after wheat emergence. Densities of 24, 40, and 65 downy brome m2reduced wheat yield by 10, 15, and 20%, respectively. Wheat yield was not reduced when downy brome emerged 21 or more days later than wheat. Economic thresholds varied with changes in downy brome density, cost of control, wheat price, and potential wheat yield. In a greenhouse experiment, dry weight of 72-day-old wheat plants grown in association with downy brome was not affected by the distance between the weeds and wheat, whereas downy brome plant dry weight increased with increasing distance between the weeds and wheat.

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