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Abstract

Perennial grain crops intercropped with legumes are expected to use nitrogen (N) resources efficiently. A pot experiment using the N-15 isotope dilution method demonstrated interspecific competition and use of N from the soil and N-2 fixation in intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey, IWG) and white clover (Trifolium repens L., WC) intercrops at five species-relative frequencies and four levels of inorganic N fertilizer in a replacement series design. The proportion of N in WC derived from the atmosphere increased from 39.7% in a sole crop to 70.9% when intercropped with IWG, and 10.1% N in IWG transferred from WC. Intermediate wheatgrass showed high fitness with maintained high total dry matter production at low relative frequencies. Decreasing IWG-relative frequency only increased dry matter and N accumulation of WC, resulting in increased amounts of N-2 fixed. Increased levels of N fertilization increased the proportion of N acquired from the fertilizer in IWG and WC but decreased the N fixed by WC and N absorbed by IWG from the soil. Our study indicates that WC supply sufficient fixed N-2 for IWG intercrop biomass yields under appropriate levels of soil N fertility and species-relative frequencies.

Keywords

symbiotic N-2 fixation; apparent transfer of N; intercropping advantages; interspecific interactions; intermediate wheatgrass; white clover; service crop

Published in

Agronomy
2021, volume: 11, number: 2, article number: 388
Publisher: MDPI

SLU Authors

Associated SLU-program

Future Agriculture (until Jan 2017)

Global goals (SDG)

SDG2 Zero hunger
SDG12 Responsible consumption and production
SDG15 Life on land

UKÄ Subject classification

Agricultural Science

Publication identifier

  • DOI: https://doi.org/10.3390/agronomy11020388

Permanent link to this page (URI)

https://res.slu.se/id/publ/111134