May is a very important month for native pastures in the southern Great Plains. By the end of this month, approximately 50% of this year’s forage production will be produced. Monitoring your native pastures that are being grazed is critical to making sure they are not being overutilized. As you evaluate your native pastures, you should see some of last year’s dead/residual growth still standing in the green new growth. If you do, you are likely stocked properly and are doing a good job with your grazing management. If you do not, now is a good time to re-evaluate your stocking rate and/or make changes to your grazing plan.
May is generally a wet month in Oklahoma and Texas, so monitoring rainfall this month and throughout the year is critical. We recommend using a water year rainfall table. The water year rainfall table allows you to determine the percentage above or below the long-term average that the actual rainfall is at the end of each month. Having this information allows you to make stocking rate adjustments.
For instance, according to Oklahoma Mesonet data, south-central Oklahoma has received 24.3 inches of precipitation for the water year beginning Oct. 1, 2019, through April 1, 2020. This is a +6.2 inch departure from normal, or, said another way, 138% of what we typically receive during this period. This is currently the 10th wettest record for this time period since 1921. The point is, things are shaping up for a very wet spring and, all things considered, should be realized in increased forage production. Understanding and monitoring rolling annual and water year tables can assist you in forecasting conditions in order to take advantage of opportunities.
Native pastures that are going to be grazed need to be monitored as well. There are several methods to do this. One is to use a grazing stick to measure forage height before livestock are turned in to graze the pasture. Select a key grazing plant. The goal is to manage for the plants you want. Your key grazing plant should be one that is well represented across the pasture and one that is selected readily. At several locations throughout the pasture, measure plant height prior to grazing. Take measurements at locations that are representative of the entire pasture. Don’t pick all the best or worst locations. As livestock graze the pasture, continue to measure plant height. When height approaches the target stubble height, it is time to rotate to the next pasture and allow that pasture to rest and recover before grazing again. Rest and recovery after a grazing event is essential to maintaining a native plant community. Another method is to use grazing exclusion cages.
Many producers use stockpiling to extend the grazing season. Stockpiling forages simply means allowing growth to accumulate during the growing season to be grazed during the winter months. Native pastures that are going to be stockpiled should be lightly grazed in May and June and then rested throughout the remainder of the growing season to achieve the maximum forage production for stockpile. For additional information on stockpiling see: www.noble.org/stockpiled-forages.
Spring brings an abundance of life. This abundance also includes species that we may or may not want in our pastures. May is a good time to scout for invasive brush species. Species like honey mesquite, a native plant that has the propensity to invade and dominate area rangelands, begins to green up in April to May. This “green up,” or bud break, is a critical time frame for this plant. This is a critical date to know as treatment options and timing can be considered based on the bud break date. If considering a foliar chemical application this summer, it is important to know when the plant is transporting carbohydrates from actively growing leaves to the roots. This period generally occurs for honey mesquite approximately 45 days after bud break. Chemical foliar applications made prior to this switch in the plant’s physiology when the plant is focused on transporting energy from the roots to develop new leaves will likely not meet control expectations.
Recognizing these considerations early in the growing season can pay positive dividends to the producer who is focused on intentional management. Ultimately, the ability to read the land by knowing what to look for can aid producers in making decisions and capitalize on opportunities.