Howard F. Schwartz, Colorado State University, Bugwood.org.
Summer has almost passed, and wetland wildlife managers across the state are planning, preparing and implementing habitat management practices in hopes of attracting and providing nutrition for migrating and wintering waterfowl for the fast approaching season. That list of activities is easier said than done this year as long-term flooding in the state, specifically the northeast region, has impacted routine waterfowl management in moist soil areas.
In a routine year, waterfowl managers commonly practice moist soil management with the intention of establishing desirable, high-quality native plants and decreasing low-value, undesirable plants. By definition, moist soil management is the drawing down of water during the growing season to promote germination of native plants. This practice is then followed by the reflooding of the area. Successful drawdowns that establish desirable native plants provide quality food and habitat for waterfowl, along with a variety of other wetland-dependent species. This management technique requires concise planning and implementation, as plant composition is driven by the timing of the water drawdown from the unit. An early season drawdown generally occurs between March 15 and May 1, or the first 45 days of the growing season. Mid-season drawdowns are indicated by the second 45 days of the growing season, May 1 to June 15. Finally, the late-season drawdown is delineated by anything beyond the first 90 days of the growing season, June 15 and later.
In a perfect world a manager is able to effectively drawdown to promote desired native plants. In years such as this when low-lying wetland areas remain flooded well into the growing season, it becomes increasingly difficult for the manager to get water off moist soil areas, and it becomes more difficult to have a desired plant response. This situation creates two types of problems: a reduced window of time for drawdown and intervening for a successful response and site conditions favored by problematic plant species. Just a few examples of problematic plants are alligator weed (Alternanthera philoxeroides), cattails (Typha spp.), beakrush (Rhynchospora corniculata), water primrose (Ludwigia peploides) and coffee beans (Sesbania herbacea). All of these species can create monocultures and reduce overall food availability. There are several options for management techniques when undesirable plants are in high densities. Those techniques include disking, mowing, chopping, herbicides, cropping and shallow flooding when problem plants are young. The situations created by the extended inundation here in the northeast region tends to greatly reduce those options, leaving a need for late-season intervention that still has the ability to produce substantial food for waterfowl. Obviously, those requirements lead to the establishment and management of small grains.
Small grains planted for waterfowl include Japanese millet or wild millet, browntop millet, foxtail millet and white proso millet. All of these options are annual plants with the ability to produce an abundance of seed even when established mid to late growing season. Japanese and browntop millet tend to be the go-to variety in the northeast region mainly due to their availability for purchase, adaptability to site index and short maturation period to dry seed. Once established, Japanese millet can be slightly inundated, making it ideal for situations where drainage is an issue. Japanese millet is an excellent reseeding variety when conditions allow for plant maturity and seed production. Japanese millet has a maturation date of approximately 55 days after germination, and the deterioration rate is 57% after 90 days of inundation. Establishment can be achieved by top-sowing 25 pounds of pure live seed per acre on a well-prepared seed bed. In top-sowing situations, using a cultipacker before and after broadcasting is great for ensuring seed-to-soil contact. If using a no-till drill, then reduce rate to 15 pounds of pure live seed per acre. Browntop millet is adapted more to a well-drained soil condition. Browntop millet is prone to lodging on fertile soils where plant height is maximized, making it ideal for placing in front of blinds where open water is needed. Maturation period for browntop millet is 60 to 65 days with a deterioration rate of 25% after 90 days. The low percentage of deterioration is another reason to place this species in front of a blind so that food availability is maintained longer and within shotgun range. Establishment and seeding rate recommendations for browntop millet are the same as Japanese millet, making the two varieties great companion plants.
Fertilizer considerations should be based on a soil test that can be provided by any local LSU AgCenter extension office across the state. If a recommended soil test is lacking, then an application of nitrogen at 40 to 60 pounds per acre when the millet has reached 4 to 8 inches tall will be advantageous.
Millets are grasses, and they open the wetland manager up to several herbicide options to gain control of problematic broadleaf plants that may be encountered. The use of herbicides to control undesirable weeds will also aid in promoting maximum seed yield through the reduction of competitive weeds at critical growth stages. Examples of available post-emergent herbicides to be used in the control of broadleaf weeds are 2,4-D; Aim; or Banvel. Please refer to the LSU AgCenter Louisiana Chemical Weed Management Guide (publication No. 1565) for labeled rates, instructions and considerations.
Finally, after establishment has been achieved, a weekly or biweekly scouting trip across the planted acreage may be necessary to monitor fall armyworm presence or damage. Scouting the entire planted area can help deduce the critical areas to avoid spraying the whole unit. Several insecticides are available for controlling armyworms, and information can be found in the LSU AgCenter Insect Pest Management Guide (publication No. 1838). Local extension agents in your respective parishes can assist you if an issue should arise.
Water levels all around the state are beginning to decline, and soon waterfowl managers will undoubtedly be ready to get into the field to conduct strategic habitat improvements. Cropping intervention may be a likely fit if you are consumed with problematic, undesirable plants and fear there isn’t enough time for native plant management. Good luck this growing season!
Luke Stamper is the LSU AgCenter area wildlife and forestry agent for the Northeast Region.