Oat, rye, and ryegrass response to N fertilizer

Authors: Balkcom, Kipling; DUZY, LEAH - Compliance Services International; Price, Andrew; Kornecki, Ted

Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2018
Publication Date: 2/14/2019
Citation: Balkcom, K.S., Duzy, L.M., Price, A.J., Kornecki, T.S. 2019. Oat, rye, and ryegrass response to N fertilizer. Crop, Forage & Turfgrass Management. 5:1-6. https://doi.org/10.2134/cftm2018.09.0073.
DOI: https://doi.org/10.2134/cftm2018.09.0073

Interpretive Summary: A cereal cover crop combined with conservation tillage can enhance soil productivity of degraded southeastern soils. Direct comparisons regarding performance of different cereal cover crops are limited. Scientists with ARS, in Auburn, AL, conducted an experiment to compare oat, rye, and ryegrass cover crop biomass performance across four nitrogen rates (0, 30, 60, and 90 lb N ac-1 as commercial fertilizer) during the 2009 to 2012 growing seasons. Each cover crop benefited from additional N, but the response to additional N varied by cover crop species. Rye was the most responsive, followed by oat, then ryegrass. Efficiency of applied N averaged 55% for rye and oat, but efficiency of applied N for ryegrass was only 21%. These results support applying some N fertilizer to promote additional rye or oat biomass production. Increased surface biomass levels can enhance cover crop benefits that will improve soil health benefits for growers.

Technical Abstract: A cereal cover crop combined with conservation tillage can enhance soil productivity of degraded southeastern soils. Direct comparisons regarding performance of different cereal cover crops are limited. This experiment, located at Auburn University’s Wiregrass Research and Extension Center in Headland, AL on a Fuquay sand (loamy, kaolinitic, thermic Arenic Plinthic Kandiudults), was designed to compare cover crop biomass performance across nitrogen (N) rates during the 2009 to 2012 growing seasons. The experiment consisted of a randomized complete block design with a split plot restriction. Main plots were cover crops [oat (Avena sativa L.), rye (Secale cereale L.), and ryegrass (Lolium multiflorum L.)] and subplots were N rate (0, 30, 60, and 90 lb N ac-1 as commercial fertilizer). Cover crop biomass responded linearly to applied N (P = <0.0001), but biomass response to N varied by cover crops (cover crop x N rate; P = 0.0001). Nitrogen content also responded linearly to applied N (P = <0.0001), and the response to N varied across cover crops (cover crop x N rate; P = 0.0044). Average maximum carbon (C)/N ratios were greatest for rye, followed by oat and ryegrass; however, 30 lb N ac-1 produced the highest ratios, regardless of species. Average nitrogen uptake efficiency (NUE) of oat (54 %) and rye (57 %) were similar, but averaged 164 % greater than average NUE of ryegrass (21 %). These results support applying N fertilizer to rye or oat as a single species cover crop when high biomass production is preferred.