Root Structure, Biomass Allocation, And Legume Intercropping Of Intermediate Wheatgrass

Abstract

Intermediate wheatgrass (IWG; Thinopyrum intermedium) is a perennial grass undergoing domestication as a grain crop, whose deep roots can reduce soil erosion and nutrient pollution. One barrier to the viability of IWG as a grain crop is an interannual decline in seed production, the cause of which is unknown. Both experiments in this thesis aim to uncover plant density-dependent relationships associated with a decline in seed production and guide future strategies to increase yield stability. The first chapter investigates the effects of intercropping legumes on IWG in two row spacings. Intercropping legumes was not found to increase IWG seed or biomass production, however, rarely did intercropping impose net competitive effects. The second chapter investigates root structure and biomass allocation using minirhizotrons. Greater root abundance was not linked to lower aboveground productivity in IWG, which suggests that IWG does not experience a biomass allocation trade-off between above- and below-ground plant tissues.