By Ryan Benjamin
Nebraska Extension Educator-Beef Systems
As we come into early April, it is important to take time to think about rangeland and pasture conditions and make sure grazing plans are ready for the growing season in 2024. Much of the state has seen close to normal precipitation since October 1 (current water year). However, parts of the state, especially counties in the south and east of the state, that experienced drought last summer are still experiencing drier than normal conditions.
Pasture and native rangeland forage production fluctuates as the growing season progresses and is influenced by precipitation, temperature, range health, the previous year’s precipitation and management, and soil nutrients. The amount and timing of spring and early summer precipitation are important factors in determining annual forage production. Using trigger dates can help producers adjust stocking rates if precipitation and the resulting forage production are expected to be below average. Trigger dates will vary depending on the dominant forage.
Available soil moisture is a major driver of plant growth. Cool- and warm-season grass species have rapid-growth windows when optimum air temperature, day length, and soil moisture are present for plants to fully express their growth potential. Once that window of opportunity has passed for a particular grass species, it is too late to get significant growth, even if it does rain. For example, cool-season grasses produce most of their growth in late spring and again in the fall, whereas warm-season grass growth occurs during the middle part of the growing season.
Precipitation during May, June, and July are strongly correlated with total forage production of warm-season species and total forage production in the Nebraska Sandhills. In the Nebraska Panhandle, many range sites are dominated by cool-season grass plants and forage production is influenced by April, May, and June precipitation. This same timeframe also applies to pastures dominated by smooth bromegrass; a cool-season grass common in Eastern Nebraska. However, smooth bromegrass is a sod-forming grass and can be very drought-tolerant. Many smooth bromegrass pastures will grow again in the late summer and early fall when day length shortens and cooler nights return.
Areas affected by drought during the previous growing season will likely experience lower forage production even if adequate moisture is available this year. It is important to give range and pasture plants the chance to recover from drought and rebuild energy reserves. To accomplish this, maintain a lower stocking rate post-drought.
Suggested trigger dates
Trigger dates for an operation will depend on the grass species present and available grazing resources. Here are some key trigger dates to consider for Nebraska cool- and warm- season dominated range sites.
April 15 to May 10. By this time, 30–45-day precipitation forecasts can have a moderate level of reliability. If above-average temperatures with average to below-average precipitation is predicted, plan additional reductions in stocking rates. In smooth bromegrass pastures with below-average precipitation, annual production may be reduced by 25-50 percent.
May 20 to June 10. Needlegrasses will be completing their forage production and western wheatgrass is in its rapid growth window. If March-May precipitation was 50-75 percent of the long-term average, reduce stocking rates 30-40 percent or more depending upon grass species and plant health. Warm-season grasses such as prairie sandreed and little bluestem are just starting to grow.
June 15 to June 30. Approximately 75 to 90 percent of grass growth on cool-season dominated range sites and 50 percent of grass growth on warm-season dominated range sites will have occurred. Rainfall after late June usually has limited benefit for cool-season grass production but could still benefit warm-season grasses.
June 15 to July 15. Precipitation and available soil moisture is critical for warm-season grass growth.
July 15. Precipitation after this date will have limited benefit to warm-season tallgrass production. However, it can still result in some forage growth from shortgrass warm-season species such as buffalograss and blue grama.
September 1 to September 15. Smooth bromegrass or other cool-season-dominated pastures need adequate precipitation by these dates for enough fall forage growth to be grazed.
For more information or to discuss your pastures and ranges, contact Benjamin at 402-376-1850.