Prescribed burning is a widely used and effective tool for managing pastures. We are entering a window where most prescribed burns are conducted in the Mississippi and the south, most pastures are burned in late winter to early spring (late January to early March). Figure 1 shows the number of acres burned per state during prescribed burns in 2018. Fire is useful on pastures that are overgrown with much dead biomass (thatch or mulch) that has accumulated over the years. Dead biomass can smother desirable plants and new seedlings, causing stands to thin and creating habitats for invasive species. A well-time burn can injure or killed undesirable species such as inva-sive wood plants, weeds, and reduce soil seed banks of invasive species.
Prescribed burning in the spring is an im-portant part of grass management. Burning a pasture will require having enough dead growth as fuel to support a fire. A hot fire will require at least 1,500 to 2,000 pounds of dry matter per acre that is dead and burn easily to provide enough heat to destroy undesira-ble species during the burning process. Burning hayfields or pastures can reduce insect and disease pressure the following summer. Reducing the thatch layer increas-es sunlight penetration to new growth in the spring and helps warm up soil temperatures and plant roots quicker, resulting in earlier green-up in the fields. Also, burning helps release nutrients into the ground that can be used by the new growth. Timely late winter burns can offer several benefits to a hay or livestock producer.
A good indication of a possible needed pre-scribed burn in your pasture is observed when the field starts to show bunches of grass in the pasture and the cattle graze around them. They try to avoid these areas where the grass in thicker with lower forage quality and then they overgraze other areas. This causes uneven utilization of the pasture and the formation of these grass clumps. It is recommended to burn your pasture only once every two or three years to maximize the health and sustainability of the pasture.
Producers that have never burn a pasture might not realize how hot and fast a fire can travel. Before planning a pre-scribed burn, especially for pastures surrounded by wooded areas, landowners should consult with the Mississippi For-estry Commission (MFC). The Mississippi Prescribed Burning Act of 1992 codified prescribed burning as a property own-er right. Liability is limited if the landowner follows the guidelines outlined in the law. Principally, prescribed burning should be in the public interest. Currently, MFC requires to get a permit before burning. Contact your county MFC for permit information. If burning conditions are not favorable, MFC will not grant a burning permit.
Controlled burning is any fire intentionally ignited to meet specific pasture management objectives, such as to reduce dead biomass, restore ecosystem health, recycle nutrients, or prepare pasture for revegetation and new growth. Before implementing a burning, the following prescribed burning basics must be met and followed.
Controlled burning is a management tool that when used under specific controlled conditions can provide benefits to the forage ecosystem. The burn window or preplan conditions for a targeted burning depends on just the right conditions of the controlled burning from both dead and live fuel moisture, air temperature, wind speed, and relative humify. There are different burning techniques that producers should be aware of before implementing a burn to make sure that the safety and goals of the burn are accomplished (Fig.2). The more common techniques are back, head, flank, and spot fire. Backfire is set at a 90-degree angle to the wind direction, so the fire burns directly against the wind. It is one of the safest methods of executing a prescribed burning and is recommended for beginning burn managers or areas with high fuel loads. Wind speed should be no more than 6 to 10 mph when implementing this burning method. Head fires are sent with the direction and should be used only under ideal fuel conditions. They can produce taller flames and burn quickly. Flank fires are implemented with the fuel load is relatively light and they are set by walking into the wind. Spot fires are set across different locations in the pasture with equal or similar distance until they gradually expand and join.
While burning pastures can improve pastureland, it can be dangerous if the conditions are hot, dry and windy. It must be done safely. To maximize the benefits of implementing a prescribed burn, timing is very crucial. Make sure that pre-scribed burning is implemented close to the regrowth of desirable pasture species to optimize nutrient cycling, nutrient uptake, and canopy closure that will reduce weed competition and improve forage nutritive value. If you are considering a prescribed burn, check with the local Mississippi Forestry Commission and be sure to obtain a permit.
For upcoming forage related events visit: http://forages.pss.msstate.edu/events.html