Cropping System Influence on Planting Water Content and Yield of Winter Wheat
David C. Nielsen*,a,
Merle F. Vigila,
Randy L. Andersonb,
Rudy A. Bowmana,
Joseph G. Benjamina and
Ardell D. Halvorsonc
a USDA-ARS, Central Great Plains Res. Stn., 40335 County Road GG, Akron, CO 80720
b USDA-ARS, Northern Grain Insects Res. Lab., 2923 Medary Ave., Brookings SD 57006
c USDA-ARS, SoilPlantNutrient Research Unit, P.O. Box E, 301 S. Howes, Ft. Collins, CO 80522

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Fig. 1. Winter wheat yield as affected by available soil water content at planting (in 0180 cm depth) at Akron, CO. (a) All data (19932001) by crop rotation; (b) data from dry years (AprilJune Pan evaporation - Precipitation >65 cm); (c) data from average and wet years (AprilJune Pan evaporation - Precipitation <65 cm).
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Fig. 2. Frequency distribution of Pan evaporation - Precipitation summed over April, May, and June at Akron, CO (19682000).
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Fig. 3. Cumulative frequency distributions of available soil water at wheat planting as influenced by rotation (19932001) at Akron, CO.
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Copyright © 2002 by the American Society of Agronomy.