By Donna Foulk
Mow Your Way to a Healthier Pasture
Mowing benefits a pasture in many ways.
- Mowing at regular intervals maintains grasses in a vegetative stage and produces a high quality, uniform pasture.
- Mowing also promotes tillering of the grass which leads to a dense, leafy sward.
- In addition to maintaining quality and productivity of favorable species, mowing also helps prevent the growth of weeds. It removes some weed species and reduces the production of weed seeds by others.
- Mowing at the proper height is important to maintain the health and survival of pasture grasses. Many grass species store their energy reserves in the bottom few inches of the plant, so mowing too low reduces their reserves and limits their ability to regrow. When mowing, maintain a mowing height of 2 to 3 inches if your pasture is composed primarily of fine-bladed, short grass species such as perennial ryegrass and bluegrass. Mow to maintain a slightly higher level of 3-5 inches if you pasture is composed primarily of taller species such as orchardgrass or timothy.
Reduce Weed Pressure
- Weeds can be a serious problem in pastures. Since some weeds can be harmful to animal health, pastures should be managed to minimize the presence of weeds.
- If you are establishing a new pasture, it is important to address weed issues prior to planting. In established pastures, the most effective weed management technique is to maintain a healthy stand of grasses and legumes which compete with weed seedlings. If weeds continue to be a problem, an herbicide application may be appropriate to suppress them. If weed pressure is high, the conditions which promote weed growth need to be addressed. Herbicide alone will not provide a long-term solution.
- The first step in any weed control program is to identify the specific species of weeds in your pasture. If you decide to use herbicides as a weed management tool, it is very important to apply the right product because the efficacy varies by species. An herbicide that eliminates one weed species may have no activity on another weed.
- In addition to selecting the correct product, it is important to apply the herbicide at the right time. To ensure the timing of application is effective to control the specific weed, it is important to identify the life cycle of the weed. Perennial weeds live more than one year and are dormant in the winter. The ideal time to control perennial weeds is late summer when the weeds are moving their food reserves into the roots. Canada thistle, curly dock, and milkweed are examples of perennial weeds that commonly grow in pastures.
- Annual weeds only live one year, but are prolific seed producers. The parent plant will die but the weed seeds that are produced can germinate and produce many plants the following year. Annual weeds exist as summer annual or winter annual weeds. Summer annual weeds produce seeds in the summer. The seeds survive the winter and germinate the next spring. A thick, healthy stand of grasses should be able to out-compete newly emerging weed seedlings in spring. If summer annual weeds do become established, then the mature weeds will be highly visible in summer, since the grasses are slowing their growth at this time due to hot, dry conditions. Mowing can sometimes effectively reduce weed seed production and will help reduce weed pressure. The ideal time to control summer annual weeds with herbicides is in late spring when the weed seedlings are very small. It is a poor decision to use herbicides on summer annual weeds in late summer because the plants have already dropped their seeds and are beginning to die. Examples of some common summer annual weeds are lamb’s quarters, ragweed, and pigweed.
- Winter annual weeds such as chickweed and mustard also live one year, but germinate from seeds in late summer. Winter annual seedlings appear in pastures in early fall and persist as plants through the winter. Winter annual weeds flower very early in spring, drop their seeds and die. By summer, winter annual weeds are no longer competitive in the pasture. However, the seeds are present and ready to germinate in early fall. Since winter annual weeds are present in spring and fall, when the cool season grasses are rapidly growing, it is rarely necessary to control these weeds. Healthy pasture grasses should be able to prevent the germination of winter annual weed seeds and reduce the survival of any seedlings. If pasture growth is very poor and the elimination of winter annuals is warranted, the best time to control them is late summer, after all of the weed seeds have germinated.
Caution:
Pesticides to control weeds should be used at the correct rate and time. When using herbicides, it is critical to follow all label directions and restrictions.
- Pastures Need Rest, Too - Rotational grazing systems improve the productivity of a pasture. Rotational grazing systems allow grasses time to rest which allows grasses time to restore energy reserves required for growth. In addition to the heavy traffic patterns of horses, the natural grazing behavior of horses is stressful on pastures. Horses tend to feed on grasses in the same area and graze the same grasses over and over because they are the most palatable. In addition, the precision of a horse’s lips and teeth allow close grazing of select plants in a pasture. Repeated, close grazing of a grass plant depletes energy reserves, reduces growth, and will eventually kill the plant.
- As stocking density increases, the implementation of a rotational grazing system becomes more important to maintain quality, productive pasture. A simple two-paddock system will improve productivity. To set up a simple two-paddock system, put one cross-fence across the pasture and rotate the horses between the two pastures. Turn animals into the pasture when the grass is 6 to 8 inches tall and allow them to graze it down to 3 to 4 inches. Development of a system with more than two paddocks will provide additional improvements in pasture performance.
- Additional steps may be required to give grasses adequate rest. During periods when grass growth is limited, restrict access to the pastures and increase the amount of hay fed. In addition, it may be beneficial to incorporate a stress lot into the rotational system. The stress lot may be composed of soil or stone dust or may be planted with a forage mixture specially formulated for higher traffic and grazing tolerance.
- Spring and fall are ideal times to plan and implement pasture improvements and improve your grazing system. To help develop a rotational grazing system and maximize the resources on your farm, the first step is to map your farm. Diagram the existing barns, pastures, and permanent fences. Consider layouts which allow you to increase the number of paddocks and still allow you to move your animals easily around your farm. Two examples of rotational grazing systems for one farm layout are presented below.
Figure 1. Two examples of rotational grazing systems.
Adopting good pasture management practices will provide a steady supply of high value forage and will generate an aesthetically pleasing and ecologically sound farm environment.
Source:psu.edu