Icebergs and Native Forages - What You Can’t See Can Sink You

In April 1912, the RMS Titanic sank off the coast of Newfoundland after an iceberg tore a hole in her hull 25 feet below the waterline. Only a tenth of an iceberg is visible above the water; most of it lurks beneath the surface. Forage plants are similar: how things look on the soil surface may not reflect what’s happening further down.

Forages use sunlight to convert carbon dioxide into plant sugars that drive plant growth. They can only do this if the roots can absorb enough water and minerals from the soil. You’ve probably seen old pictures of a healthy grass plant with enormous roots extending deep into the soil, and overgrazed grass plants with shallow root systems.

With drought a recurring reality in many regions, you might wonder what affects pastures more – the drought or overgrazing during drought? Dr. James Cahill and co-workers at the University of Alberta studied how grazing season and intensity affected forage yield and root mass under drought conditions (Differential sensitivity of above- and belowground plant biomass to drought and defoliation in temperate grasslands;