Silage on the top of a bunker silo can vary in temperature — and perhaps quality — depending on whether it is covered by white plastic or black plastic.

Researchers at Cornell University discovered that the temperature of silage under black covers was 10 degrees warmer than silage under white covers when measured 12 inches into the pile. The silage covered in black plastic also was 20 degrees warmer when measured 6 inches into the pile. The chart below summarizes the results.

More sugars may be utilized during fermentation in warmer silage, which may lead to lower quality.

Maximum temperature variation
White Plastic Versus Black Plastic (Degrees Fahrenheit)

Measured at 6 inches from top of pile

20 1
Measured at 12 inches 10 2
Measured at 24 inches 5 3

1Day 30 of ensiling. Summertime afternoon reading.

2Day 34 of ensiling. Summertime afternoon reading.

3Day 36 of ensiling. Summertime afternoon reading.