Cover crop species can increase or decrease the fertilizer-nitrogenrequirement in maize

CARCIOCHI, WALTER; MASSIGOGUE, IGNACIO; LAPAZ, ADRÏAN; CAFARO LA MENZA, FRANCISCO; SAINZ ROZAS, HERNÁN RENÉ; BARBIERI PABLO ANDRÉS; DI NAPOLI, MARCELO; GONZALEZ MONTANER, JORGE; CIAMPITTI, IGNACIO

AGRONOMY JOURNAL

AMER SOC AGRONOMY

Año: 2021

0002-1962

Cover crop species and termination date could affect fertilizer-nitrogen (N) manage-ment and N diagnostic methods traditionally used in bare fallow-maize (Zea maysL.) systems. Our objectives were to (a) assess the effect of cover crop terminationdate on maize yield and response to fertilizer-N, (b) determine maize yield at vary-ing N rates following different cover crop species and mixtures, and (c) evaluate thechlorophyll meter reading (CMR), grain N concentration (Nc), and grain N nutri-tion index (NNI) as N diagnostic methods. Experiments were conducted at four sitesin the southeastern Argentinean Pampas with maize planted after cover crops. Fac-tors investigated were cover crops with vetch (Vicia villosaRoth), vetch–oat (AvenasativaL.) mixture, or bare fallow; early termination of cover crops or∼3wklater;and maize fertilizer-N at 0, 50, 100, and 200 kg N ha–1. The minimum N rate thatmaximized grain yield was higher in vetch–oat mixture (100 kg N ha–1) than in vetch(50kgNha–1). Maize yield was not affected by cover crops with 200 kg N ha–1.Latetermination dates of vetch–oat mixture reduced maize yield by 15% compared withearly termination dates, while there was no effect of vetch termination date. Covercrop termination date did not affect yield response to fertilizer-N. Relative CMR atsilking, grain Nc, and especially grain NNI at maturity were useful tools to diagnosemaize N status and cover crop effect. Cover crop management should be consideredto adjust the fertilizer N rate and optimize maize productivity.