Location: Natural Resource Management Research2011 Annual Report
1a. Objectives (from AD-416)
Specific objectives of this research include: Objective 1. Provide management guidelines to improve the conservation and enhancement of agroecosystem function and structure in grasslands of the NGP. Objective 2. Improve the viability of cattle production on the NGP by providing management strategies that increase the efficiency of forage utilization. Objective 3. Develop methods to alter the composition of beef so that it better meets the emerging market demand for healthier beef.
1b. Approach (from AD-416)
An automated rainout shelter will be used to simulate drought conditions and test if early-season water stress and (or) defoliation following water stress will have greater impact on productivity of switchgrass or western wheatgrass or on mixtures of western wheatgrass and alfalfa. The influence of soil attributes on growth characteristics of perennial grasses will be determined with greenhouse evaluations using soil collected under native vegetation and under severely weed invaded plant communities at four sites between Mandan, ND and Pierre, SD. Field-based estimates of the greenhouse gases carbon dioxide and nitrous oxide will be used to determine if soil emissions of nitrous oxide offset carbon uptake by moderately grazed mixed-grass prairie. Satellite-based estimates of plant canopy carbon:nitrogen ratio will be determined for five native rangeland pastures and these estimates will be used to determine if they can be used to estimate forage quality for pastures on the northern Great Plains. Trials with cattle will be conducted to determine if grazing higher quality forages with supplemental flaxseed and (or) forages containing condensed tannin will result in reduced methane emissions per unit of beef produced and greater economic returns. Other trials with cattle will be conducted to determine if omega-3 fatty acid levels in beef can be raised substantially if fattening yearlings are fed flaxseed or flaxseed oil that is treated to protect the alpha-linolenic acid in it from hydrogenation by ruminal microbes.
3. Progress Report
Termination of an earmark linked to the Rangeland and Livestock Resource Management research project resulted in the elimination of a vacant animal scientist position. A new PDRAM was developed and reflected the position loss by eliminating Subobjectives 2.1, 2.2, and 3.2. For Subobjectives 1.1 and 1.2, manuscripts are being prepared. For Subobjective 1.4, monitoring and assessing rangeland carbon flux and canopy condition continued with additional support from the US Forest Service and new field studies at the Grand River National Grassland, and a manuscript detailing this work is in review. For Subobjective 2.3, the sheep tannin trial was completed and the cattle tannin trial is underway. For Subobjective 3.1, two manuscripts are being prepared on this research.
1. Incorporating alfalfa in rangeland increases soil organic matter. Management interventions are needed to concurrently increase forage production on native rangelands while improving the soil resource. Incorporation of alfalfa into rangelands represents one such intervention, though information regarding the influence of alfalfa on key indicators of soil health is limited. ARS researchers in Mandan, ND, documented the effects of alfalfa interseeded into rangeland on soil organic matter, a fundamental building block for creating healthy soil. They discovered soil organic matter increased by 3.1 tons per acre under two of the three interseeded alfalfa cultivars, and was related to increased forage yield compared with rangeland without alfalfa. This study highlighted a management intervention that concurrently increases forage production while improving the health of rangeland soils.
Deiuliis, J., Shin, J., Murphy, E., Kronberg, S.L., Eastridge, M.L., Suh, Y., Yoon, J., Lee, K. 2010. Bovine adipose triglyceride lipase is not altered and adipocyte fatty acid binding protein is increased by dietary flaxseed. Lipids. 45:963-973. DOI: 10.1007/s11745-010-3476-2.