Event Title

Nitrogen Requirements in Irrigated Small Grains After Alfalfa

Presenter Information

Collin Pound

Location

Logan Golf & Country Club, Logan, UT

Start Date

3-26-2019 5:00 PM

End Date

3-26-2019 7:00 PM

Description

Small grains are commonly grown following alfalfa in Utah, especially during drought years as they require less irrigation than corn. Studies across the country have shown that corn following alfalfa rarely needs N fertilizer, yet relatively few have evaluated the N needs of small grains. Furthermore, research on the N needs of small grains grown as forage vs. grain are even more sparse. The objectives of this research are to quantify the N contributions of alfalfa to small grains and develop N guidelines for the first and second year following alfalfa termination, to determine the economics of alfalfa-corn vs. alfalfa-small grain rotations and whether early spring soil nitrate tests or plant chlorophyll content at flag leaf could predict N response. Irrigation type will be evaluated to see if there are any effects on N response. Experiments were conducted on 18 sites in Utah and Colorado in 2018. Four sites had direct comparisons of small grains harvested as grain vs. forage, while another five and nine sites were harvested as grain or forage only, respectively. At each site, four replications of six N rates ranging from 0 to 168 kg N ha-1 were applied in the spring as ammonium nitrate. Early results indicate that N fertilizer was not needed to increase small grain yield at most sites. These results will help growers better utilize N credits from alfalfa, improve their small grain yield and profit, and reduce negative implications of excessive N fertilizer applications that could contaminate runoff and groundwater supplies.

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Mar 26th, 5:00 PM Mar 26th, 7:00 PM

Nitrogen Requirements in Irrigated Small Grains After Alfalfa

Logan Golf & Country Club, Logan, UT

Small grains are commonly grown following alfalfa in Utah, especially during drought years as they require less irrigation than corn. Studies across the country have shown that corn following alfalfa rarely needs N fertilizer, yet relatively few have evaluated the N needs of small grains. Furthermore, research on the N needs of small grains grown as forage vs. grain are even more sparse. The objectives of this research are to quantify the N contributions of alfalfa to small grains and develop N guidelines for the first and second year following alfalfa termination, to determine the economics of alfalfa-corn vs. alfalfa-small grain rotations and whether early spring soil nitrate tests or plant chlorophyll content at flag leaf could predict N response. Irrigation type will be evaluated to see if there are any effects on N response. Experiments were conducted on 18 sites in Utah and Colorado in 2018. Four sites had direct comparisons of small grains harvested as grain vs. forage, while another five and nine sites were harvested as grain or forage only, respectively. At each site, four replications of six N rates ranging from 0 to 168 kg N ha-1 were applied in the spring as ammonium nitrate. Early results indicate that N fertilizer was not needed to increase small grain yield at most sites. These results will help growers better utilize N credits from alfalfa, improve their small grain yield and profit, and reduce negative implications of excessive N fertilizer applications that could contaminate runoff and groundwater supplies.