Location: Range and Livestock Research2008 Annual Report
1a. Objectives (from AD-416)
Objective 1: Develop strategies and decision tools to proactively manage livestock grazing, fire, and drought impacts on Great Plains community structure and function. Sub-objective 1.A. Determine plant community and livestock response to post-fire grazing deferment. Sub-objective 1.B. Determine plant community response to fire return interval and seasonality. Sub-objective 1.C. Determine patch burning effects on plant community dynamics, animal performance, grazing distribution, and foraging efficiency. Sub-objective 1.D. Characterize grazing history effects on rangeland integrity and stability. Objective 2: Improve animal productivity and product quality based on predicted nutrient intake, forage dynamics, and diet selection processes in the northern Great Plains. Sub-objective 2.A. Determine effects of forage quality on autumn forage intake as it interacts with cow lactation and gestation status. Sub-objective 2.B. Determine rumen microbial response to noxious weed consumption by sheep and cattle. Objective 3: Develop management strategies to restore rangelands degraded by weeds and prevent weed invasions in the northern Great Plains. Sub-objective 3.A. Determine interacting effects of fire and grazing on annual brome dynamics. Sub-objective 3.B. Provide weed management protocols adjusting for inter-annual variation. Sub-objective 3.C. Develop an internet-available system to quantify site-specific invasive weed impacts. Sub-objective 3.D. Develop grazing strategies to reduce invasive weed population growth rates.
1b. Approach (from AD-416)
The planned research is designed to improve sustainability of rangeland production by addressing the interacting effects of disturbances on stability and integrity of rangelands and efficiency of livestock nutrient conversion. Objectives are to: 1) Develop strategies and decision tools to proactively manage livestock grazing, fire, and drought impacts on Great Plains community structure and function; 2) Improve animal productivity and product quality based on predicted nutrient intake, forage dynamics, and diet selection processes in the northern Great Plains; and 3) Develop management strategies to restore rangelands degraded by weeds and prevent weed invasions in the northern Great Plains. Experiments are integrated across objectives and will determine the interacting effects of grazing, fire, drought, and invasive plants on plant communities (production, species composition, diversity, heterogeneity, propagation, and survival) and the effects of changes in vegetation and animal physiology on livestock (weight gain, distribution, diet quality, diet selection, diet diversity, foraging efficiency, forage intake, and rumen microbial diversity). Two experiments are replicated across three locations (Miles City, MT, Nunn, CO and Woodward, OK) to determine ecological ramifications of fire seasonality, return interval, and grazing interactions in semiarid rangelands on a north-south gradient across the western Great Plains. Understanding the mechanisms that control disturbance effects on rangelands and animal responses to alterations in the plant community will promote development of proactive management strategies for improved stability in rangelands and rangeland livestock production systems.
3. Progress Report
This report documents research conducted under the in-house associated project CRIS 5434-21630-002-00D, Proactive Management for Sustainable Rangeland Production. All milestones were fully met and primarily limited to treatment application and data collection during this first reporting period. This project addresses goals outlined in the NP 215 Rangeland, Pasture and Forages Action Plan under Component I (Rangeland Management Systems to Enhance the Environment and Economic Viability) and supports ARS strategic plan Objective 5.1 (Provide Science-Based Knowledge and Education To Improve the Management of Forest, Rangelands, and Pastures). More specifically, experiments in this project target the following objectives of the NP 215 Action Plan: Objective A.2, Determine impact of livestock grazing, fire, mechanical treatments, and drought on ecological integrity and watershed structure and function; Objective B.1, Develop monitoring and decision-support tools and management strategies for land managers; Objective B.4, Assess near- and long- term animal productivity, well-being and product quality under alternative rangeland management strategies; and Objective C.1, Understand mechanisms of weed invasion and develop management strategies that can be used to restore rangelands that have been degraded by weeds and other disturbances. Portions of this project are related to or coordinated with research in NP 304 Crop Protection and Quarantine (weed biology and ecology; plant, pest and natural enemy interactions and ecology).
1. An Internet-Available System for Estimating Weed Impacts Without knowing what a weed is costing, it is difficult to decide how much to spend on controlling it. An internet-available model has been developed that estimates current spotted knapweed and leafy spurge impacts: http://220.127.116.11/WeedImpact/. The model requires that weed density data be gathered by randomly depositing a sampling frame about the site of interest. The data are input into a website, and the website calculates estimated weed impacts on desired plant species and forage production. Also, the website translates reductions in desired plant species (weed presense impacts) into reductions in same year livestock carrying capacity. This project supports NP 205 Component, Ecosystems and their Sustainable Management, while addressing Problem Area, Ecological and Economical Sustainability.
5. Significant Activities that Support Special Target Populations
MacNeil, M.D., Haferkamp, M., Vermeire, L.T., Muscha, J.M. 2008. Prescribed fire and grazing effects on carbon dynamics in a northern mixed-grass prairie. Agriculture, Ecosystems and Environment 127:66-72.