Location: Agroecosystem Management Research
Project Number: 3042-21600-001-013-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 20, 2024
End Date: Jul 19, 2028
Objective:
Maintain all grazing treatments and measurements annually as part of this project that include full greenhouse gas flux for CO2, CH4 and N2O for continuously grazed fertilized brome pastures compared to rotational grazing, not fertilizing but with 30% more area, and supplementation to improve cattle performance while cattle ‘fertilize’ pasture with nitrogen via urine. The grazing-land plots are aspirational in two areas: rotational grazing and supplementation without fertilization. We have measured GHG flux for the previous 5 years on continuous grazed, fertilized cool-season pastures. In addition to continuing that monitoring, the impact of supplementation or rotationally grazing will be compared for impacts on GHG flux, cattle performance, and pasture performance on both animal- and land-based units of measure.
Approach:
A smooth bromegrass pasture (8.1 ha) is set aside specifically for grazing by growing beef steers to measure long term impacts of grazing and GHG emissions from cattle. Each year, 25 steers continuously graze the pasture from early May until late September. Within this pasture CO2, CH4 and N2O flux are being monitored; along with plant and soil measurements. Additional smooth bromegrass pastures (7.3 ha each) were enrolled in the LTAR project. Each pasture is subdivided into 3 treatments and 5 steers rotationally graze each replication throughout the grazing season. The 3 treatments include 1) Pastures fertilized with 90 kg N/ha (2 ha paddocks), 2) Cattle supplemented daily at 0.6% of body weight with dry distillers grains plus solubles (2 ha paddocks) 3) Control pastures with cattle rotationally grazing, but no fertilizer or supplement added (2.9 ha paddocks). These treatments have been continuously implemented since 2005 in order to study the long-term effects of N inputs into the system.
