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Research article - Peer-reviewed, 2023

Nitrate leaching losses and the fate of 15N fertilizer in perennial intermediate wheatgrass and annual wheat — A field study

Huddell, Alexandra; Ernfors, Maria; Crews, Timothy E.; Vico, Giulia; Menge, Duncan N.L.;

Abstract

Perennial grains, such as the intermediate wheatgrass (Thinopyrum intermedium) (IWG), may reduce negative environmental effects compared to annual grain crops. Their permanent, and generally larger, root systems are likely to retain nitrogen (N) better, decreasing harmful losses of N and improving fertilizer N use efficiency, but there have been no comprehensive N fertilizer recovery studies in IWG to date. We measured fertilizer N recovery with stable isotope tracers in crop biomass and soil, soil N mineralization and nitrification, and nitrate leaching in IWG and annual wheat in a replicated block field experiment. Nitrate leaching was drastically reduced in IWG (0.1 and 3.1 kg N ha−1 yr−1) in its third and fourth year since establishment, compared with 5.6 kg N ha−1 yr−1 in annual wheat and 41.0 kg N ha−1 yr−1 in fallow respectively. There were no differences in net N mineralization or nitrification between IWG and annual wheat, though there was generally more inorganic N in the soil profile of annual wheat. More 15N fertilizer was recovered in the straw and all depths of the roots and soils in IWG than annual wheat. However, annual wheat recovered much more 15N fertilizer in the seeds compared to IWG, which had lower grain yields. 15N-labeled fertilizer contributed little (<3 %) to nitrate–N in leachate, highlighting the role of soil microbes in regulating loss of current year fertilizer N. The large reduction in nitrate leaching demonstrates that perennial grains can reduce harmful nitrogen losses and offer a more sustainable alternative to annual grains.

Keywords

Nitrate leaching; 15N fertilizer; Intermediate wheatgrass; Perennial grains; Agroecology

Published in

Science of the Total Environment

2023, volume: 857, number: Part 1, article number: 159255

Authors' information

Huddell, Alexandra
Swedish University of Agricultural Sciences, Department of Biosystems and Technology
Swedish University of Agricultural Sciences, Department of Biosystems and Technology
Crews, Timothy E.
The Land Institute
Swedish University of Agricultural Sciences, Department of Crop Production Ecology
Menge, Duncan N.L.
Columbia University

UKÄ Subject classification

Agricultural Science
Ecology

Publication Identifiers

DOI: https://doi.org/10.1016/j.scitotenv.2022.159255

URI (permanent link to this page)

https://res.slu.se/id/publ/119311