Weather Effects on Corn Silage

The variation in our weather from year to year and location to location has a substantial impact on corn silage quality in our region. This variation causes dairy producers and nutritionists the need to adjust rations to maintain high milk production levels. The accompanying table summarizes some of the effects of weather on yield and several forage quality traits of corn. Most of these data were adapted from a summary by Coors and Lauer (2001) from studies in the Netherlands and New York, but our data from Pennsylvania studies would support them as well.

Table 1. Weather Effects on Corn Silage

Factor

DM Yield

Digestibility

Fiber Content

Fiber Digestibility

High temperature

+

-

+

-

High light intensity

+

+

-

High populations

+

-

+

Delayed planting

-

-

+

Delayed harvest

-

-

-

Drought

-

-

+

+

-, +, : negative, positive and mixed effects on the trait

Higher temperatures can increase DM yield, but cause more respiration to occur late in the season and reduce grain fill. High light intensity (lack of cloudy days) promotes good grain fill that has positive effects on whole plant digestibility. As plant densities increase, yields often increase, but reduced sugars and starch in the silage may lead to slightly lower whole plant digestibility. Delaying harvest tends to reduce dry matter slightly, decrease digestibility, and here in Pennsylvania, often decreases the fiber content and fiber digestibility. Drought generally reduces yield, and grain content. This increases the fiber content but this is often accompanied by lower lignin production that increases the fiber digestibility. In seasons where the drought comes at the end of the season, sometimes the grain content is reduced but the stalks are large and well lignified, so the fiber digestibility is not increased.