Campus Units

Agronomy

Document Type

Abstract

Publication Version

Published Version

Publication Date

2016

Conference Title

ASA-CSSA-SSSA Annual Meeting

Conference Date

November 6–9, 2016

City

Phoenix, AZ, United States

Abstract

Nitrogen balance provides a measure of agroecosystem performance and environmental sustainability by taking into accounts of N inputs and outputs and N retention in the soil. The objective of this study was to evaluate N balance due to N inputs and outputs and soil N sequestration rate after 7 yr in response to five dryland crop rotations (two 4-yr stacked and two alternate-year rotations and one monocropping) and two cultural practices arranged in a split-plot design in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)-durum-canola (Brassica napus L.)-pea (Pisum sativum L.) (D-D-C-P) and durum-durum-flax (Linum usitatissimum L.)-pea (D-D-F-P). Alternate-year rotations were durum-canola-durum-pea (D-C-D-P) and durum-flax-durum-pea (D-F-D-P). Monocropping was continuous durum (CD). Cultural practices were traditional (conventional till, recommended seed rate, broadcast N fertilization, and reduced stubble height) and ecological (no-till, increased seed rate, banded N fertilization, and increased stubble height). Total annual N input due to N fertilization, pea N fixation, atmospheric N deposition, crop seed N, and nonsymbiotic N fixation was lower in CD than other crop rotations, regardless of cultural practices. Total N output due to crop grain N removal and N losses due to denitrification, volatilization, plant senescence, N leaching, gaseous N (NOx) emissions, and surface runoff was lower in traditional CD and D-F-D-P than traditional D-C-D-P and ecological D-C-D-P, D-D-C-P, and D-F-D-P. Nitrogen sequestration rate at 0-125 cm from 2005 to 2011 averaged 50 kg N ha-1yr-1 for all treatments. Nitrogen balance was negative and lower with CD than other crop rotations, regardless of cultural practices. Because of reduced reliance on external N inputs and increased grain N removal, N flow, and N surplus, crop rotations with legumes, nonlegumes, and oilseed crops in the rotation had positive N balance and can be productive and environmentally sustainable compared with monocropping, regardless of cultural practices.

Comments

This is an abstract of a presentation from the ASA-CSSA-SSSA Annual Meeting, Phoenix, AZ, November 6–9, 2016. Posted with permission.

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

Share

Article Location

 
COinS