AgWatch

Post Drought Pasture Vigilance

SIMPSON, ILL.
   Pastures this summer have taken a huge hit - cooked by the high temperatures that stopped growing; the majority of forages have slipped into weakened dormancy rather than death. Due to limited hay resources, many producers were forced to allow livestock unlimited access to pastures during the drought which further weakened plants. Grazing and hoof traffic removed leaves necessary for photosynthesis. Lack of adequate forage during the drought caused animals to graze available grasses down to the soil.
   The lack of moisture this summer and fall suppressed plant growth and retarded root development. Without adequate root structure, plants are unable to extract moisture and nutrients from the soil, further limiting plant growth. With growth already limited by drought, the plant was forced to utilize more of its stored sugar to grow replacement leaves. Repeated use of the pasture can eventually deplete the plant’s energy reserves, resulting in death of the plant or severely reducing its chance for survival.
   Even after we received some rains, pasture regrowth at the Dixon Springs Ag Station was slow and immediately consumed by livestock. When the drought breaks, it is important to assess your pastures for damage. Carefully identify plants and make sure they are truly forages and not weeds. Some pastures will recover with rest, restricted grazing, and appropriate fertilization. Other pastures may require complete renovation to be productive again.
   Weeds are exceptionally hardy, so it’s not surprising they thrive in drought conditions. Weeds steal sunlight, soil nutrients and water away from desirable pasture plants. They have little nutritional value and some weeds are poisonous if grazed. Ensure your animals have adequate forage or supplemental feed available so they avoid the temptation of sampling harmful plants.
   It can be tempting to start grazing as soon as additional moisture greens up your pastures. However, grazing too soon on drought-weakened pastures can cause plants to further decline, prolong recovery time or even kill the plants.
   Moisture alone does not overcome drought stress. Plants draw from their energy stores to survive drought and need a period of recovery to replenish these reserves and establish new root growth. Complete rest is the most effective and fastest way for pastures to recover. Ideally, pastures should rest for an entire growing season, but may not be practical.
   If you must permit grazing in the season following a drought, plants should be at least 6 to 8 inches high before animals have access to pasture. Avoid overgrazing and re-stressing the pasture by removing animals when plants have grazed down to 3 to 4 inches.
   In general, pastures are more productive with proper fertilization. Resist applying anything without knowing what is needed. Perform a soil test first to identify what nutrients your pasture is lacking.
   Pastures with a low potential for recovery may have to be reseeded or renovated. Depending on the extent of the damage, some pastures may benefit from overseeding bare areas or introducing a legume species to improve pasture quality. Pastures hit hard by drought may only become productive after complete renovation, which can be expensive and require that the land be taken out of production for one to three years.
   Following a drought, pastures are weak and less able to compete with vigorous weeds (especially annual species). Be prepared for several years of vigilance and identify any unknown weeds that might be harmful to animals. Δ
DR. TERESA L. STECKLER: Extension Specialist, Animal Systems/Beef, University of Illinois

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