Exploring the relationships between biomass production, nutrient acquisition, and phenotypic traits: testing oat genotypes as a cover crop

Abstract

High biomass and nutrient acquisition are desirable for oat (Avena sativa L.) as a cover crop. However, our understanding of oat genotypes suitable for cover crops and associated traits is limited. The objectives of this experiment on growing oat as a cover crop, after winter wheat (Triticum aestivum L.) harvest, were to determine biomass production, nutrient uptake of a set of oat genotypes, and to identify phenotypic traits that can be used as indicators to select cultivars suitable for cover crops. The results showed that the top biomass-producing genotypes took up larger amounts of soil nutrients, up to 142 kg N ha⁻¹ and 17 kg P ha⁻¹ in 2016, and 43.5 kg N ha⁻¹ and 8.3 kg P ha⁻¹ in 2017. The biomass production was significantly related to plant height and leaf area index (LAI) in both years, and to the normalized difference vegetation index (NDVI) in 2017. Both NDVI and LAI were closely related to the total amounts of N and P uptake. The poor association between biomass and NDVI in 2016 was due to vigorous growth of volunteer wheat and weeds as well as severe rust (Puccinia coronata f. sp. avenae Eriks.) infestation. Our results suggest that it is important to choose oat varieties as cover crops. Leaf area index can be used as a nondestructive indicator for final biomass and nutrient acquisition, while both NDVI and LAI are important traits for choosing oats as soil conservation cover crops.

Keywords:

• Oat
• biomass
• cover crop
• fraction to maximum
• LAI
• NDVI
• nutrient acquisition

Acknowledgements

This study was financially supported, in part, by the Canadian Agricultural Partnership project J-002090 through the Collaborative Research and Development Agreement between Agriculture and Agri–Food Canada (AAFC) and the Canadian Field Crop Research Alliance (CFCRA). We are thankful for the technical assistance provided by Lynne Evenson and Scott Patterson (retired) of AAFC. We thank Peter Johnson, Ellen Sparry, and Martin Quentin for useful information when the study was initiated. AAFC-ORDC contribution No. 21-004.

Disclosure statement

The authors declare no conflicts of interest.