Ability of cereal species for nitrogen uptake from cover crop rhizodeposits is not related to domestication level

Abstract

AbstractBackgroundCereal cultivars vary in root traits, and it can be proposed that wild forms and old cultivars are more adapted to using organic nitrogen (N) sources.AimsInvestigating N uptake from cover crop (CC) rhizodeposits by wheat and barley of different domestication level and their wild relatives, we expected a more efficient N uptake by wild forms and old cultivars, indicated by higher N uptake from rhizodeposits per root biomass.MethodsEleven wheat and seven barley cultivars categorized into three domestication levels (wild, old, and modern) were grown under controlled conditions in pots with soil containing 15N‐labelled CC rhizodeposits. Shoot and root biomass, their 15N‐uptake, and a range of root traits were analyzed.ResultsDomestication level was a weak predictor of root architecture. N taken up from rhizodeposits was similar in all plants at 14% of plant N. Cultivars with largest values for most root traits (e.g., root length or volume) and root to shoot ratio also showed largest total N uptake and N uptake from rhizodeposits. However, N uptake efficiency (N uptake from rhizodeposits per root biomass) was smallest for these cultivars. Two modern wheat cultivars showed the largest N uptake efficiency from CC rhizodeposits, whereas in barley a wild and an old cultivar showed the largest efficiency.ConclusionsIn our study with a limited number of cultivars, domestication level is not related to the ability of cereals to take up N from CC rhizodeposits. The same proportion of N derived from rhizodeposits irrespective of cultivar or root traits indicates that the N provision from rhizodeposits was driven by other factors like mineralization. However, some cultivars had a larger N uptake efficiency.