Tillage and Nitrogen Rate Effects on Area- and Yield-Scaled Nitrous Oxide Emissions From Pre-Plant Anhydrous Ammonia

Document Type

Article

Publication Date

3-2015

Abstract

Precision-guided technologies enable corn (Zea mays L.) growers to apply pre-plant anhydrous ammonia (NH3) parallel to intended corn rows even when full-width tillage follows NH3 application. Close, but crop-safe, proximity of NH3 to corn rows may potentially increase N use efficiency and lower N requirements and nitrous oxide (N2O) emissions. Experiments in 2011 and 2012 on silty clay loam Mollisol near West Lafayette, IN, assessed area- and yield-scaled N2O emissions when spring pre-plant NH3 was applied at recommended (202 kg N ha−1) and reduced rate (145 kg N ha−1), in no-till (NT) and conventional tillage (CT) systems following NT soybean [Glycine max (L.) Merr.]. Each 12-cm deep NH3 band was positioned 15 cm from, and parallel to, intended corn rows using precision guidance. Nitrification of NH3 in application bands was 31% faster under CT than NT. Area- and grain yield-scaled N2O emissions were N rate dependent in both growing seasons. On average, CT+202 kg N resulted in highest area-scaled (mean = 2.45 kg N ha−1) and grain yield-scaled (mean = 360 g N Mg−1) N2O emissions. In contrast, CT+145 kg N had similar yield-scaled emissions as NT+202 and NT+145 kg N, and reduced area-scaled N2O emissions by 65, 45, and 19% respectively, relative to CT+202 kg N, NT+202 kg N, and NT+145 kg N treatments. These preliminary results suggest that reducing pre-plant NH3 rates by ∼30% under CT has the potential to reduce N2O emissions without significant yield declines in the CT phase of a NT–CT rotation, despite faster nitrification in CT.

Publication Title

Agronomy Journal

Volume

107

Issue

2

First Page

605

Last Page

614

DOI of Published Version

10.2134/agronj14.0440

Publisher

Wiley

Rights

© 2015 American Society of Agronomy

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