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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Environmentally Integrated Dairy Management Research » Research » Publications at this Location » Publication #324665
Title: Production and nitrogen-use efficiency of oat forage receiving slurry or urea

Author
item Coblentz, Wayne
item Jokela, William
item CAVADINI, JASON - University Of Wisconsin

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2016
Publication Date: 7/11/2016
Citation: Coblentz, W.K., Jokela, W.E., Cavadini, J.S. 2016. Production and nitrogen-use efficiency of oat forage receiving slurry or urea. Agronomy Journal. 108:1390-1404.

Interpretive Summary: Fall-grown oat offers good yield potential in the north-central US as a late-season (sometimes emergency) forage crop. Furthermore, it provides a window of opportunity during mid-summer for manure distribution after the previous crop is harvested and before the oat is planted in August. Most of the research on fertilizer and manure application rates for oat is based on oat planted in the spring, not August. So we conducted a study to determine an appropriate fertilizer rate for fall-grown oat. We also wanted to determine how much dairy manure slurry should be applied to equal this fertilizer rate. In addition to determining these application rates, the results also suggested that fall-grown oat is an aggressive scavenger of nitrogen, which may provide dairy producers with an additional tool to limit nitrogen losses through leaching, thereby reducing associated environmental burdens.

Technical Abstract: Recently, several research projects have evaluated fall-grown oat for use as emergency fall forage throughout the north-central US; however, using fall-grown oat in cropping programs also allows the practical benefit of summer manure distribution that is completely de-coupled from corn production. ‘ForagePlus’ oat was seeded into replicated plots fertilized with urea at rates of 0, 20, 40, 60, or 100 kg N ha-1, or with dairy slurry applied at approximately 42,300 and 84,600 L ha-1 (105 and 209 kg N ha-1, respectively). Apparent N recoveries from fall-grown oat plots fertilized with urea ranged from 65.8 to 89.8%, which suggests aggressive scavenging of N, but calculation of these high apparent N recoveries also was dependent on relatively low pre-plant concentrations of soil NO3-N, as well as a good DM yield response to N fertilization (Y = - 0.114 x2 + 29.9 x + 2130; R2 = 0.982). For this study, applications of high and low rates of dairy slurry yielded respective N-fertilizer equivalencies of 38 and 45 kg N ha-1 for fall-grown oat, which are roughly equivalent to Wisconsin recommendations for cereal grains (45 kg N ha-1). Apparent N recoveries following application of the high and low rates of dairy slurry were 18.1 and 25.5%, respectively; however, when expressed on the basis of NH4-N applied, apparent N recoveries for fall-grown oat averaged 53.5%, and did not differ on the basis of slurry-application rate. Fall-grown oat appears to be an effective scavenger of N applied as NH4-N from dairy slurry.