Sandy silt loam soil may hamper the inoculation effect on lucerne (Medicago sativa L.) growth

ABSTRACT

Despite newly approved lucerne cultivars, this has not led to increased use of this legume in high-latitude agriculture. Challenges with inoculation by Rhizobium meliloti have been identified as a bottleneck to adaptation. Here we tested inoculation sources (ISs) with soil types and cultivars in pot and field experiments. During a one-year outdoor pot experiment, we tested the impact of IS (wet peat slurry and Nitragin Gold dry inoculation) and three soil types (sand, sandy silt and /peat soil) on nodule development, shoot and root growth and winter survival of one hybrid lucerne cultivar (‘Ludvig’). The pot experiment revealed that dry inoculation led to significant better plant growth, flower and nodule development as well as plant regrowth after winter survival. Peat soil appeared as the best growth medium and silty soil limited inoculation efficiencies. In field trials at two locations differing in soil characteristics using similar ISs, and three hybrid lucerne cultivars (‘Lavo’, ‘Live’ and ‘Lotte’) biomass yield during two ley years showed site as well as cultivar differences. Such environmental interactions in the field trials justify the use of adapted cultivars, and dry inoculation should be recommended for practical use replacing peat slurry inoculation.

KEYWORDS:

• Dry matter yield
• nitragin gold
• peat slurry inoculation
• root nodules
• rhizobia
• shoot:root ratio

Acknowlegdements

This work was funded by a grant from the Norwegian Research Funds for Agriculture and Food Industry for the project ‘Smart renewal of long-term grassland: towards higher productivity and profitability’ (LONGTERMGRASS, FFL/JA. 255176). The inoculation product (Nitragin Gold) was supplied by DLF Trifolium, DK. Rune Jakob Furset and Merete Myromslien are acknowledged for their work with the pot experiment and root scanning at Fureneset and similarly Roberts Sturitis and Mari Hansen Vold at Tjøtta for root scanning and the technical staff at Løken and Tjøtta for the fieldwork. We also thank Dr. Phil Murray, UK, for his valuable input to the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Norwegian the Research Funding for Agriculture and Food Industry (Foundation for Research Levy on Agricultural Products (FFL) and the Agricultural Agreement Research Fund (JA)).

Notes on contributors

Ievina Sturite

Ievina Sturite is a research scientist at NIBIO Division of Food Production and Society who has worked on many topics related to grasslands and nutrient turnover in the plant-soil system. She is currently involved in several projects related to carbon storage in agricultural soils.

Tor Lunnan

Tor Lunnan is a retired research scientist at NIBIO Division of Food Production and Society who worked for many years with grass and legume plants, nutrient supply in leys and grassland management.

Liv Østrem

Liv Østrem is a retired research scientist at NIBIO Division of Food Production and Society who worked for many years with plant breeding, grass and legume testing and plant adaptation to changing climate.