Every spring, ranchers face the same difficult challenge—trying to guess how much grass will be available for livestock to graze during the upcoming season. Since May 2019, an innovative Grassland Productivity Forecast or “Grass-Cast” has been helping producers in the northern and southern Great Plains reduce this economically important source of uncertainty. Officially launched this spring, Grass-Cast is now available to producers throughout New Mexico and Arizona.
Every spring, ranchers face the same difficult challenge—trying to guess how much grass will be available for livestock to graze during the upcoming season. Since May 2019, an innovative Grassland Productivity Forecast or “Grass-Cast” has been helping producers in the northern and southern Great Plains reduce this economically important source of uncertainty. Officially launched this spring, Grass-Cast is now available to producers throughout New Mexico and Arizona.
Grass-Cast uses over 30 years of historical data about weather and vegetation growth—combined with seasonal precipitation forecasts—to predict if rangelands in localized areas (6-miles by 6-miles in size) are likely to produce above-normal, near-normal, or below-normal amounts of vegetation for grazing.
Grass-Cast can provide ranchers and rangeland managers with an indication of what productivity could be like in the upcoming growing season relative to their area’s 30+ year history. Grass-Cast also gives ranchers a view of rangeland productivity in the broader region to help with larger-scale decision making, such as determining where grazing resources might be more plentiful if their own region is at risk from drought.
Producers should not rely on Grass-Cast as a sole source for making management decisions. Similarly, public land managers should not use Grass-Cast as a sole source of information for setting stocking rates, determining turnout dates, or for other aspects of lease agreements, allotments or permits.
The first publicly available forecast for the Southwest was released in May 2020, specifically for the spring season (which ended on May 31). Grass-Cast maps for the Southwest’s summer growing season will be posted to the Grass-Cast website in mid-June. These maps will provide productivity estimates for rangelands at the peak of the growing season.
Grass-Cast’s accuracy improves as the growing season unfolds, so it should be consulted more than just once during the growing season. The grassland productivity forecasts are updated every two weeks to incorporate newly observed weather data and emerging trends in growing conditions.
Grass-cast is the result of collaborations between the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS), Climate Hubs, and Natural Resources Conservation Service (NRCS); the National Drought Mitigation Center (NDMC); Colorado State University and the University of Arizona. Funding from USDA ARS and NRCS, as well as NDMC and the USGS has supported Grass-Cast’s expansion to the Southwest region.
Visit the Grass-Cast website (https://grasscast.unl.edu/) for updates, the latest maps, and other resources.
Grass-Cast contact: Dannele Peck, Director, USDA Northern Plains Climate Hub, dannele.peck@usda.gov
USDA Southwest Climate Hub contact: Emile Elias, Director, emile.elias@usda.gov
Authors: Dannele Peck, Emile Elias and Lauren Kramer