A Model to Predict Winter Wheat Emergence as Affected by Soil Temperature, Water Potential, and Depth of Planting1
- M. J. Lindstrom,
- R. I. Papendick and
- F. E. Koehler2
Establishment of adequate stands of winter wheat (Triticum aestivum L.) in northwest USA is often hampered by low soil temperature or moisture, or by deep planting to reach moisture sufficient for emergence. Because of the wide variability and interactive effects among these factors, it is often difficult to predict the rate and extent of emergence of field plantings. A model was devised to predict emergence time of ‘McCall’ and ‘Nugaines’ winter wheat as a function of soil temperature between 5 and 25 C, water potential down to −10 bars, and planting depth. Predictions were reasonably good when compared with field measurements, particularly at high water potentials and with shallow planting. In general, the emergence rate progressively decreased with lowering of water potential, lowering of temperature from 25 C, or with increase in planting depth. The lower limit or minimum water potential for emergence increased with increasing temperature. Both wheats responded similarly to temperature decreases; however, the emergence rate of each variety responded differently to change in water potential. Differences in varietal response to water potential can possibly be characterized in terms of two parameters in the function describing the water potential effect on emergence.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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