Why it Doesn’t Pay to Push Your Pasture
By Brittany Neumeier, AAg, Agri-Environmental Specialist, North Battleford
Managing pastures for maximum productivity is a long term goal, but weather fluctuations, forage inventory damage or any other unforeseen circumstances can cause you to rethink your management options. During times of dry conditions, the urge to maximize the use of what little forage growth there is may be overwhelming. Before doing so it is important to consider the future consequences of pushing pastures to obtain more grazing days.
No Roots – No Grass
Roughly two-thirds of total plant growth occurs below ground, while the above ground portion only makes up one-third. The extensive root system forms the lifeline for forage plants and helps ensure long-term survival as well as productivity. Moisture stress can reduce or impair root growth even without added grazing pressure. When plants are repeatedly grazed without a recovery period, the root system becomes increasingly shallow. This results in plants that are less vigorous, robust and productive.
Litter is an Insurance Policy
You might think that leaving plant material behind after a grazing period is a waste. However, the amount and distribution of dead plant material, also known as litter, left on a pasture is an essential component of a healthy pasture and ecosystem. The litter left behind helps to shade and cool the soil. This reduces evaporation and conserves moisture. Litter also helps to protect the soil from erosion and maintains soil stability.
Removing every blade of grass decreases the litter carryover and increases recovery time. The amount of rest needed depends on the amount of leaf area remaining after grazing and the time of grazing during the growing season. Under ideal conditions, effective rest for tame pastures is four to six weeks. However, if limited moisture is available the plant will not regrow as quickly and a longer rest period is needed. Under these conditions, overgrazed plants will stop allocating resources to root growth and instead use root reserves for leaf regrowth in an attempt to survive short-term. If dry conditions persist into subsequent years and overgrazing has occurred, desirable plants will first reduce production and eventually disappear from a pasture.
It Takes Moisture to Grow Grass
There are no quick-fix solutions to forage growth under dry conditions. The absence of moisture will inevitably result in an absence of forage growth. Under these conditions, adjusting stocking rates and using alternative feeding systems helps protect pastures and ensures animal requirements are being met. Ahead of these conditions, there are some management options to help increase available moisture in the soil during dry times. Help reduce soil temperatures and evaporation by ensuring all soil is covered and shaded by plant material. Maintaining wetlands and water features, both in the field and adjacent to the field, helps replenish and restore ground water. Outside of wetlands, plants and leaf litter also slow down precipitation, allowing it to soak into the ground and into the water reserves rather than just rushing off the landscape.
As tempting as overgrazing pastures in dry conditions is, it can cause the loss of production in subsequent grazing seasons. Leaving sufficient carry-over and allowing enough time for plants to recover may be the hardest but most critical grazing management decisions made during dry conditions. Fencing to create paddocks will help reduce grazing pressure in desirable grazing areas and will increase forage use of less desirable species.
The Farm Stewardship Program, funded through the Canadian Agricultural Partnership, offers grazing management programs. The Native Grazing Management and Riparian Grazing Management BMPs offer a 50 per cent rebate up to $10,000.00 to help in the cost of implementing exclusion or cross fencing. To find out if you are eligible or for more information about pasture management, please contact a specialist near you or contact the Agriculture Knowledge Centre at 1-866-457-2377.