Fig. 1.
Fig. 1.

Photograph of a front-mounted roller/crimper constructed by Pennsylvania State University. The roller/crimper is 3.2 m in length by 51 cm diameter by 3.2 mm thickness and weighs 1520 kg.

 


Fig. 2.
Fig. 2.

Cumulative daily precipitation for 2005 (closed circles) and 2006 (open circles) in Rock Springs, PA, for the 2005 and 2006 cropping seasons.

 


Fig. 3.
Fig. 3.

Cumulative daily growing degree days (GDD) for 2005 (open circle) and 2006 (closed circles) in Rock Springs, PA, for the 2005 and 2006 cropping seasons. Growing degree days were calculated by the following equation: GDD = [(T max + T min)/2] – T base, where T max is the maximum daily temperature, T min the minimum daily temperature, and T base is the base temperature (4.4°C) (Nuttonson, 1958).

 


Fig. 4.
Fig. 4.

Percentage control of cereal rye cultivars 6 wk after rolling/crimping by cultivar, planting date, and termination date (years pooled). Acceptable control of cereal rye cover for planting date and termination date combinations was achieved at the 85% control threshold. Bars represent standard error of the means.

 


Fig. 5.
Fig. 5.

Percentage cereal rye control in 2005 (triangles) and 2006 (circles) as related to phenological development. The lines represent the fitted three-parameter sigmoidal dose response curve regressions for 2005 (solid line; y = 95.37/[1 + exp{−7.99[log(x) – log(43.91)]}] and for 2006 (dashed line; y = 99.39/(1 + exp{−8.90[log(x) – log(50.22)]}). Data are pooled over cultivar due to no significant cultivar effects.