Winter can be a stressful time for pasture plants, but sending them into the cold months ahead fully prepared will result in better growth when warmth returns next spring. With dry conditions already putting a strain on our pastures, how we manage this fall can have a big impact next year.
Plants and humans both use carbohydrates as a source of energy. However, unlike us, plants can’t carb load with a bowl of spaghetti when they need a boost, they have to produce their own energy. Typically, plants are able to do this just fine through photosynthesis, However, when temperatures get too low, like during the winter, or water is scarce during a drought, plants shut down their energy production and draw upon stored reserves to get by.
As we head into fall, plants sense cooler temperatures and shorter days and begin to build up energy stores to make it through the coming winter. Grazing in the late summer and fall impacts reserve build up in two ways, 1) by forcing the plant to remobilize already stored energy for regrowth and 2) by reducing the amount of plant leaf area, reducing its photosynthetic potential. Both impacts impart a level of stress on the plant at a critical time of the year.
This is especially true for grasses that have already been grazed in early and mid-summer. They have already been busy trying to restore leaf area and have lowered their reserves in the process. Similarly, plants already stressed by a lack of moisture have not been able to function at a high level and haven’t been able to build reserves up throughout the season like normal. In heavy drought situations, photosynthesis has been almost shut down completely, and plant has been using energy from the reserves instead of storing it.
So how do we manage animal needs, with plant needs when grazing pasture this fall? 1) Don’t over graze. The take half leave half adage has stuck around for a reason. Leave half of the plant’s overall growth in tact to maintain photosynthetic ability and reduce the need for regrowth.
2) Rotate pastures. Grazing the same pasture over and over again at the end of the year continually puts that pasture’s plants in a deficit as they head into winter. While plants can survive a few years of this, doing so over and over again decreases plant vigor. Instead, choose a pasture to graze last that has not be grazed yet this year, or has had adequate time for rest from an earlier grazing period. Pastures that have lower levels of drought stress are also a good candidate.
3) Utilize other forage sources. Late summer planted annual forages can provide early fall feed while crop residues and cool season annual forages can fill in the gap later on. Once cold temperatures set in, grazing dormant pastures can be done with lower impact on plant health and crop residues can be grazed without the high cost of harvested feeds.
4) Finally, plan for a sacrifice area if it is needed. Sometimes we just have to overgraze. However, we can choose where this will occur, how large of an area will be impacted, and how we want to facilitate recovery in the years ahead. While not ideal, with a plan, damage can be limited.
A dry year means giving pastures time to rest before winter is more important than ever. Take half-leave half, rotate which pastures are grazed last from year to year, and utilize alternative forage sources for a healthy pasture next year. If you do need to overgraze, plan to limit the damage and how to recover pasture health in the future.
-Ben Beckman is a beef systems Extension Educator serving the counties of Antelope, Cedar, Knox, Madison and Pierce. He is based out of the Cedar County Extension office in Hartington. You can reach him by phone: (402) 254-6821 or email: ben.beckman@unl.edu