Heat Effects on Alfalfa
When it gets hot, alfalfa plants grow more slowly and moisture stress becomes common, even in moist soil. Maintaining high-quality hay is very difficult due to the high temperatures, especially when the heat does not subside at night. High night-time temperatures cause rapid respiration rates in alfalfa, burning off nutrients that plants accumulated during the day. This often produces alfalfa hay with fine stems that contain high protein, more fiber and lower feed value than expected.
Another problem with heat is how fast alfalfa plants mature. When it is hot, alfalfa may begin to bloom in less than four weeks. If you use blooming as a signal to harvest, this early bloom can be misleading. Early blooms may not mean the plant has fully recovered from the previous cutting.
During hot weather, alfalfa plants need more time, not less time, to rebuild nutrient reserves in their roots because they lose more to respiration. So, watch the calendar along with plant maturity to determine when to cut your alfalfa fields. Waiting longer may support stand health, but forage quality will continue to decline as the crop matures.
Finally, you might adjust the time of day when you cut hay. Some research has shown that cutting in late afternoon produces higher quality hay than cutting in the morning. However, on good drying days it may still be wiser to cut in the morning.
When hay in the windrow stays above 50% moisture, plant cells continue to respire, burning away nutrients. Hay cut late in the day respires all night long, losing yield and quality. On good drying days, plant cells can dry enough to be stabilized before nightfall, reducing respiration losses.
Getting high-quality hay can be challenging on a good day, but during heat waves, it can be even more so. Use the calendar, plant condition and drying forecast together to plan harvest for better results than relying on bloom or time of day alone.
Yucca Control on Rangeland
Yucca, also called small soapweed, is a common weed in western and central Nebraska rangelands. Yucca plants are especially noticeable when flowering in June. In some areas, high plant density can significantly reduce grass production, so yucca may need to be managed to reclaim grazing lands.
Once established, yucca plants can flourish on drier range sites due to their deep taproots, which compete aggressively for the limited soil water. With sharp leaves, cattle rarely eat these plants during summer, and grass production decreases where yucca thrives.
General broadcast spraying to control yucca is cost prohibitive, although small patches can and should be controlled before they expand. Labeled herbicides include Remedy®, Tordon 22K®, Chaparral + 2,4-D or Cimarron Plus® + 2,4-D for yucca suppression of individual plants.
Hexazinone products like Velpar L®, Pronone Power Pellet or Velossa® can be applied to the soil on the uphill side of individual yucca plants with an exact delivery hand-gun applicator. Herbicides are most effective when applied in spring or early summer.
When using herbicides, be sure to follow label directions for the best control.
Winter grazing with cattle and bison can provide some yucca control success. During winter, yucca is often the only green plant prevalent, and some cows may chew through the base of the plant to get to the moist, tender parts. After several consecutive winters of grazing, yucca stands can be reduced, allowing grass to thrive during summer.
Whether it is with herbicides or trying some winter grazing, reclaim your pasture(s) from yucca.
Late Rain and Brome Pastures
Summer rain can turn a smooth brome pasture from brown to green, but it cannot replace spring forage production that was missed.
Common in eastern Nebraska pastures, smooth bromegrass is a cool-season grass that makes much of its growth during April, May and early June. Many pastures entered spring stressed from a dry fall and winter, then missed timely spring moisture. Much of their main production window may already be gone.
Late rain can still stimulate new leaves, but that growth may be more valuable for plant recovery than additional grazing. New brome regrowth is highly palatable and can be grazed off quickly, especially when cattle have immediate access after rain.
Walk pastures rather than judging them from the road. Look beyond the green color and seedheads. Check plant height, leaf area, residual forage, bare ground and whether cattle repeatedly graze the same areas.
Where forage remains short, slow rotations, increase recovery time, reduce grazing pressure or locate additional feed. Early weaning or marketing lower-priority animals may be needed if the forage budget remains short.
The goal is not to harvest every green leaf. Maintaining leaf area now gives stressed brome plants a better chance to rebuild vigor this fall and produce forage next spring.
