November 30, 2022

Extension Notebook: Don’t assume pastures will be forgiving

By Teresa L. Steckler

To say that this year has been a little strange is an understatement. I was perusing over the U.S. Drought Monitor maps (https://droughtmonitor.unl.edu/). The Oct. 13 map clearly shows that most of the U.S. could use slow, soaking rains. Colleagues harvesting at a test station in Mississippi are having the same issues as Illinois — beans harvested at below normal moisture at 7% to 8%. Normal is 13%.

Southern Illinois has been dry most of the summer, evident by the poor quality and low volume of hay harvested. Some areas received timely rains, but that was short-lived. Pastures in many areas are brown with little to no stockpiling of cool season forages. Several pastures that I have seen are already down to dirt. Cattlemen in some areas are feeding bales of hay.

Now is a critical time for pastures. Decreasing day length, upcoming freezing temperatures, and no rain will impede growth. Especially hard on pastures is overgrazing when temperatures allow for plant growth. If there is growth, the plants are taking reserves out of the roots, which can affect performance next spring.

No one knows for certain what the weather will bring next year, but if we again have below normal rainfall patterns, overgrazing can be particularly hard on plants as we are stacking one stressor (drought) on top of another (grazing), putting plants in a difficult position to recover from during a normal year, let alone without adequate water. Drought plans should be implemented to reduce stocking rates and limit the potential for overgrazing.

Managing livestock: Reduce stocking rates if forage supplies are limited. First, cull cows that are old, open, in poor condition or have poor disposition. While checking pregnancy status, also check for health problems (poor udders, eye and feet issues, poor disposition) that warrant elimination from the herd. Open livestock are difficult to justify feeding expensive hay or grazing. If available, move livestock to leased pastures where forage is boot high or greater.

Those with fall-born calves may want to consider early weaning calves and prepare (precondition — vaccinations and bunk broke) them to be sold. This will reduce the stocking pressure on your pastures and nutrient requirements of your cows. Delaying this decision will cause pastures to be depleted sooner. I would recommend keeping replacement heifers on the cows as long as possible (early weaned heifers may nurse herd mates after calving).

Grazing management: The amount of forages left after animal grazing is the biggest key factor in how well your pasture will bounce back. This is a juggling act between getting the most out of your forages while leaving enough to grow back. Keep in mind that it is critically important to not overgraze your pastures.

Letting your grasses have enough rest in between grazing is a major factor in having lush pastures or scrubby, weed-infiltrated pastures. If plants have enough rest, then the root system will stay healthy. Keeping the roots healthy will determine how well the plant can take in moisture and nutrients and grow back.

Depending on the species of the forages, usually pasture plants need to grow to 8 to 10 inches before you let the animals back onto the field. Types like Bermuda grass can handle more grazing because they have above- and below-ground runners. Forage regrowth will depend on several factors — starting growth height, soil nutrient availability, rainfall, and season of growth are examples — thus time to achieve this growth will be variable. Once you turn livestock out onto the pasture, monitor plant height and pull them off once they have grazed the forages down to about half of the original length.

Those pastures with little or no green growth are living off the roots, and root mass has declined substantially. Roots must be replaced, or bare areas will increase, and invader grasses/weeds will prevail. In addition, overgrazing plants removes the buds needed for re-growth. If insufficient stubble and root remains, water capture and infiltration is reduced. So, when it does rain again, less water will enter the soil stores for plant growth.

Fertilizer inputs should be reduced or stopped during periods of prolonged reduced precipitation, and deferred grazing should be considered to increase harvest efficiency, forage utilization and flexibility of herd management.

Weed management: Think twice before applying herbicides during a drought. Plant mechanisms in response to a drought will prevent adequate entry of herbicides into plants and result in a high-cost application with little control of the specific weed.

There are many pastures across Illinois that are “toast” this year, so what can be done to allow those “toasted” pastures to recover? One strategy is to install interior fencing to prevent cattle from overgrazing new growth on drought-stricken pastures. Manage grazing by rotating the remaining cattle through pastures, monitoring closely the projected number of grazing days (weeks) ahead of the herd and the recovery rate of the pastures. If grazing expectations are not being met without overutilizing the pastures, destocking protocols should be further implemented.

Weeds can be problematic when pasture grasses are grazed down and do not return quickly. Apply herbicide only if the target weeds are actively growing and not drought-stressed, usually early in the season. Make weed control a priority over fertility on introduced pasture if one must be chosen over the other.

We cannot predict conditions the next growing season will hold. Impacts from drought on pasture can be immediate and more long-term. Without moisture, plant growth slows or stops, reducing our production and grazing potential for the year. If the stress of drought is prolonged or compounded by another stressor like overgrazing, impacts can be felt for years. Perennial species take time to build back vigor and strength as their energy reserves recover. This may drop productivity for several grazing seasons as well as increase the likelihood of continued overgrazing and the opportunity for the establishment of invasive weeds.

Take stock of your pastures — have the forages grown back sufficiently or have they been overgrazed? Understanding the impact of severely reduced rainfall or drought on your pasture can provide direction for planning and mitigating impacts. Planning ahead can reduce the long-term impacts and help make difficult decisions easier in the heat of the moment.

Teresa L. Steckler is a University of Illinois Extension specialist, commercial agriculture.