Grazing Bites by Victor Shelton, Retired NRCS Agronomist/Grazing Specialist I’m not going to throw any particular grazing management system under the bus. I’m also not going to intentionally target continuous grazing systems, even though it might be hard to call some of them a “system.” Most can have situations where they are surprisingly successful when one important factor is in their favor – a stocking rate low enough to prevent gross overgrazing and allow adequate recovery. All too often forage is allowed to rest but not really recover. There is a difference. Rest is simply time without another grazing or cutting event. Recovery is the ability for the plant to rebuild after that event. A pasture may sit untouched long enough to produce a decent flush of green growth, but that does not necessarily mean it has recovered. A hayfield may also be greening up after harvest while plants are still rebuilding their “solar panels,” replenishing energy reserves, restoring roots and replacing weakened tillers. It has had rest, but perhaps not enough recovery. Adequate recovery occurs when forage has rebuilt enough leaf area to photosynthesize efficiently, replenished much of the energy used during regrowth, maintained or increased tillering and resumed healthy root growth. How long that takes depends on season, moisture, temperature, fertility, species and, perhaps most importantly, how much leaf area was left behind. In practical terms, recovery looks like a full, leafy canopy, vigorous vegetative growth, new tillers and plants that have rebuilt enough reserves to withstand another grazing without being set back. That is why residual matters so much. A plant left with four inches of healthy leaf starts recovery with a functioning solar panel already in place. A plant grazed or mowed tightly must rebuild much of that leaf area before getting back to replenishing reserves and growing roots. It is almost shocking how much quicker forage can recover when adequate residual is left behind. Mechanical harvest can be more demanding because it usually removes forage more uniformly and leaves less residual than well-managed grazing. In either case, the principle is the same: time alone does not equal recovery. Rest is measured with a calendar. Recovery is measured by the plant. Before I get too deep into this discussion, I want to go back to what I said about continuous grazing sometimes being successful. In many cases, that success is being paid for with a low stocking rate, sometimes low enough that livestock cannot keep up with all the desirable forage during rapid growth. It can work, but it is not necessarily an efficient use of the forage being grown. What is more concerning are pasture systems where desirable forage isn’t getting enough recovery between grazing events. When that happens repeatedly, plants gradually lose vigor. Selective grazing can make it worse because livestock return to the plants they prefer while less desirable species are left with more leaf area and more opportunity. Add stressful growing conditions for cool-season forages and the pasture can begin shifting toward the plants livestock wanted least in the first place. That was especially noticeable this year on numerous farms, including some that are generally managed quite well. Nimblewill and Japanese stiltgrass were especially troublesome. Nimblewill expanded where cool-season forage lost vigor and canopy, while Japanese stiltgrass took advantage of many of the same thin and weakened areas from seed. The pasture can start looking less like a productive forage stand and more like a salad bar stocked with all the wrong greens. That doesn’t necessarily mean the pasture was poorly managed. Sometimes weather simply stacks the deck against us. But repeated grazing without adequate recovery makes it much easier for undesirable species to take advantage. So, what can we do about it at this point in the season? A lot of the answer comes back to recovery, but in some fields what is really needed is a period of deferment. It will be especially important this fall not to continue grazing fields already struggling to maintain desirable species. Those fields may need to be deferred for the remainder of fall and through winter so cool-season forages can take advantage of whatever favorable growing conditions remain. That deferment allows plants to rebuild leaf area, strengthen crowns and tillers, replenish energy reserves and improve root growth before winter. Grazing weakened cool-season forage just before dormancy removes leaf area when plants need it most to replenish root and crown reserves, potentially setting the stand back even further. When growing conditions are favorable, one of the most useful things we can do for a pasture shifting in the wrong direction is simply stop grazing it. If hay is available, this may be a year to start feeding a little earlier and use that hay to buy more recovery time. Bale grazing on stockpiled forage or other suitable ground can also help shift pressure away from the fields that most need deferment while putting nutrients back where they can do some good. Giving up some grazing now may help produce a stronger, more productive and better-quality pasture next season. Clipping may also help where taller weeds or rank undesirable growth are shading desirable forage. The goal isn’t to make the field look neat; it is to reduce competition and get more sunlight to the plants we want to encourage. Cutting everything short, though, simply creates another defoliation event for the plants we’re trying to help. Fertility should also be considered. If soil tests show deficiencies, correcting them can give desirable cool-season forage a better chance to respond during the remaining fall growth period. Nitrogen may help grass growth where appropriate, while potassium can be especially important for plant vigor, stress tolerance and overwintering. But fertility cannot replace deferment. Sometimes the best thing we can do for a struggling pasture in the fall is quit grazing it, reduce unnecessary competition, correct fertility where needed and let the plants use the rest of the growing season for themselves. It is not about maximizing a single grazing event but optimizing the entire grazing season. Keep on grazing. Reminders & Opportunities Free Heifer Selection Event – Oct. 24, Southern Indiana Purdue Ag Center, Dubois. Info/registration: Jason Tower at towerj@purdue.edu |
