There have been several articles printed in NF Ag News and Views on the topic of acceptable stubble height for adequate re-growth and persistence of certain grasses. Stubble height is the average height measured from the soil surface to the height of actively growing leaves. Although I am a forage specialist by trade, even I have a hard time getting very excited about measuring the height of grass leaves. I do, however, have a keen interest in sports football, to be more exact. So I figured if I could put the two together, I can make part of my job more interesting and get the point across to producers in a different, but still effective, manner.
Have you ever heard the phrase "That pasture's been ballparked?" That means it's either been severely overgrazed or hayed short so that it appears as smooth and even as a ballpark or a golf green, in some really bad cases. To that extreme, ballparking a pasture normally isn't a good thing to do. This practice removes too much leaf area to permit timely regrowth, which gives weeds a competitive advantage, reduces fertilizer efficiency, increases erosion potential and normally results in poor livestock performance due to inadequate daily forage intake.
Sometimes, however, given the right forage, ballparking a pasture is not so detrimental and can even facilitate proper pasture management. Such a situation could be over-seeding ryegrass in a bermudagrass pasture in the fall and intentionally overgrazing the bermudagrass. This practice facilitates ryegrass germination by "treading-in" the seed with high stock densities of livestock. This practice normally does not adversely affect bermudagrass production but could be very detrimental if the forage base were perennial native grass.
So the effect of ballparking a pasture depends on the type of forage team you have and the season in which you're playing the game. I'd wager that a large percentage of you reading this article have played football or baseball in a pasture once or twice in your lifetime. Normally, the pasture isn't grazed or hayed as short as the previous example, and, as long as the grass isn't so thick that you can't see the ball, the game isn't usually affected too much. So we have the ballpark system of proper grazing management. The time of year and the base forage will dictate the minimum stubble height for timely re-growth and production and therefore what type of ballpark is appropriate.
For example, with bermudagrass, you should begin grazing when you can drop a baseball in it and still see the top of the ball (about 3 inches tall). You can allow for occasional periods during rapid growth in the spring where the average height of the bermudagrass is the height of a golf ball (1 1/2 inches), but rotational grazing is highly recommended to allow for re-growth prior to the middle of summer. The only time that bermudagrass should be allowed to be deeper than a basketball (9-10 in.) is when accumulated for hay or winter stockpile. In my experience, the highest forage quality on bermudagrass is obtained when managed for softball (3 1/2 in.) depth throughout the grazing season under rotational grazing. High-quality winter stockpiled bermudagrass is obtained by starting with softball (3 1/2 in.) in August, fertilizing and hopefully finishing with basketball (9-10 in.) or greater prior to first frost.
Warm-season perennial native grass mixtures that are dominated by tall to mid grasses like Indiangrass, switchgrass, or little bluestem should be initially grazed when grass heights average deeper than an over-inflated basketball (10-12 in.) and are managed to be no less than a football (7 in.) deep prior to first frost. Actually, football season year-round through rotational grazing works very well on mixed grass prairie. Bahiagrass can be managed the same as bermudagrass, but will get very coarse and unpalatable if managed for golf (1 1/2 in.). Dallisgrass should be managed for no less than softball (3 1/2 in.) or the plant growth form becomes more mat-like than upright making it harder for cattle to graze. Begin grazing crabgrass at softball level (3 1/2 in.), and stock heavy enough and rotationally graze to keep it from getting much more than football (7 in.) or forage quality will decline, and pasture production and season of use will be decreased. Grazing should be initiated on Old World bluestems at football depth, grazed no lower than softball depth during the growing season, and allowed to go to football season again in the fall, prior to first frost.
These situations represent the major warm-season grass species present in the southern Great Plains. Right now is the time to make sure that your forage team is in the right ballpark prior to opening day (first frost). Hopefully, this method will make judging proper pasture use a little more interesting. Now get out there and play ball!