Every Monday for the past couple of months on the OSU Extension crop team conference call I have heard Jim Noel from the National Weather Service say that across Ohio we are in a pattern of above average temperatures and below average rainfall. These are not encouraging words for a grazier to hear. This isn't the type of forecast conducive to good pasture growth. Summer pasture growth is dependent upon rainfall and pasture management. Rainfall we can't control. Management though is a different story. So what's your plan to manage through a hot, dry summer?
Regardless of the weather pattern, you should stick to what you know as a grazier, as a manager of pasture plants. Those pasture management principles that you learned at a grazing school, or through a grazing council, or from an experienced grazier will serve you in good stead through this weather pattern. Let's review those principles and how they are applied when it is hot and dry.
The take half, leave half principle must be followed during the summer months. That remaining leaf area provides a photosynthetic base for plant regrowth, shades the soil to keep the soil temperature cooler, and it helps to reduce soil moisture loss. Do not cheat on this principle during hot, dry spells. It is critical to maintain a 4 inch grass height to get the benefits mentioned. Maintaining this leaf residue provides the grass plant the best opportunity to take advantage of those spotty rain events that are common to hot, dry years, allowing regrow much sooner than overgrazed pasture paddocks.
The second principle that must be adhered to is to provide a rest period that is sufficient to allow plants to grow back to a practical grazing height. The height at which grazing should begin is somewhere in the 8 to 10 inch range. Obviously the two principles work hand in hand. In practice this means that grazing rotations slow down during hot, dry periods. It is easy to do just the opposite.
Grass is growing slowly. In order to maintain a 4 inch residual I move my livestock into the next paddock a little early. Maybe the grass is only 7 inches tall. If I want to maintain a 4 inch residue, I'll have to leave this paddock a little sooner than the time my livestock can normally graze in this paddock. The grass in my next scheduled paddock is only 6 inches tall. Maybe I should just let them graze this current paddock down a little bit lower, say 3 inches. This pattern continues and soon I am either grazing down to a 2 inch height, which pretty much stops regrowth during 90 degree days with no rainfall, or I am trying to get my livestock to only take off an inch or two of grass growth, which is pretty tough to do. The end result is that paddock moves are speeding up and leaving behind paddocks that are overgrazed. The next rotation puts me in even worst shape.