Nitrogen Limitation in Hay Meadows
This past February in Jackson County, Daniel Adamson, a graduate research assistant at the University of Wyoming, discussed their first year of research on nitrogen (N) limitation in hay meadows. Lately, research on high-elevation irrigated meadows has been hard to come by, and these types of agricultural operations provide valuable forage and ecosystem services because of how they are irrigated and managed. Adamson’s research is adding some much need insight into these unique forage systems.
There was some discussion on the key factors to meadow management: water management, forage species effects, N-fertilization, and harvest timing. In terms of water, how we irrigate these fields has a significant impact on the species composition of a meadow. Intermittent or continuous irrigation improves different types of forage species, and improved species increases yield and quality.
However, this research is focused on the “thatch," organic layer, or sod that forms in these meadows. This and prior research have found that anywhere from 1 to 2.2 tons of N/acre is tied up this layer of organic material. How do we utilize this source of N?
Adamson and staff from UW are working with four ranches in the Laramie Valley, WY and North Park Valley, CO. All ranches are above 6,500 ft in elevation and use flood irrigation. In the first year of this study, they wanted to confirm not only the amount of N build-up in irrigated meadows, but that the majority of that N is contained in the O-horizon: the first 2 inches of the soil profile. The diagram below compares the amount and placement of N between rangeland and a fertilized and irrigated meadow.
Going forward, the research has multiple goals:
· Better understand and describe what soil and vegetation properties affect N-availability.
· Define what is “healthy” and productive meadow soil.
· Examine the impact of light mechanical and livestock disturbance and interseeding practices on improving N
We will keep following Daniel’s research and look forward to more results soon! You can see the slides from his presentation here!