|ARRIAGA, FRANCISCO - University Of Wisconsin|
|DELANEY, DENNIS - Auburn University|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/13/2018
Publication Date: 6/21/2018
Publication URL: https://handle.nal.usda.gov/10113/6563658
Citation: Balkcom, K.S., Duzy, L.M., Arriaga, F.J., Delaney, D.P., Watts, D.B. 2018. Fertilizer management for a rye cover crop to enhance biomass production. Agronomy Journal. 110:1233-1242. https://doi:10.2134/agronj2017.08.0505.
Interpretive Summary: Winter cereal cover crops are necessary to achieve maximum benefits of conservation tillage in the Southeast. These benefits generally increase as cover crop biomass increases. ARS scientists, in Auburn, AL, conducted a three year experiment to evaluate nitrogen (N) application times, sources, and optimal rates to maximize cover crop biomass production in conservation tillage systems. Commercial fertilizer produced 13% greater biomass compared to poultry litter across all rates and application times. Poultry litter, when compared to commercial fertilizer N, was more expensive to apply, which limited its value as an N source when biomass production was only considered. Climatic events, such as heavy rainfall, are known to influence N fertility requirements for crops. However, based on climate observed across the duration of this experiment, results indicate farmers apply a fall application of commercial fertilizer N to provide superior cover crop biomass, as well as increase surface residue on southeastern soils.
Technical Abstract: Winter cereal cover crops are necessary to achieve maximum benefits of conservation tillage in the Southeast. These benefits generally increase as cover crop biomass increases; therefore, we conducted a study to evaluate nitrogen (N) application times, sources, and optimal rates to maximize cover crop biomass production at Headland, AL on a Fuquay sand (loamy, kaolinitic, thermic Arenic Plinthic Kandiudults) during the 2006-2008 growing seasons. Main plots were time of application (fall and spring), subplots were N source [commercial fertilizer and poultry (Gallus gallus domesticus) litter], and sub-subplots were N rate [0, 34, 67, and 101 kg N ha-1 as commercial fertilizer and 0, 2.2, 4.5, and 6.7 Mg ha-1 as poultry litter (as-sampled basis)] for a rye (Secale cereale L.) cover crop. Commercial fertilizer produced 13% greater biomass compared to poultry litter across all rates and application times. Lower biomass production and higher costs for poultry litter reduced the feasibility of poultry litter as an N source compared to commercial N. Higher carbon (C)/N ratios were measured for fall applied N compared to spring applied N, while N fertilizer recovery efficiency (REN) averaged 37% across the experiment. Results indicate fall application of commercial fertilizer N produced superior results across cover crop metrics examined in this study, while providing general information about N fertilizer requirements to increase surface residue associated with cover crops across the southeastern US.