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

• Li, Shoujiao

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

• Jensen, Erik Steen

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

• Dimitrova Mårtensson, Linda-Maria

  • Department of Biosystems and Technology, Swedish University of Agricultural Sciences
    

Associated SLU-program

Future Agriculture (until Jan 2017)


Sustainable Development Goals

Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss
End hunger, achieve food security and improved nutrition and promote sustainable agriculture
Ensure sustainable consumption and production patterns


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