Impact of wheat cultivar development on biomass production and carbon input in tillage-eroded soils

Abstract. Crop biomass, especially from belowground, improves soil health and recovery. However, the effects of cultivar traits and tillage erosion on biomass production, particularly root biomass, remain unclear. We quantified root system characteristics throughout the wheat growing season, considering different cultivars and varying soil erosion gradients. This data informed a model assessing cultivar performance on root biomass production under different soil water and erosion scenarios. Tillage erosion reduced total wheat biomass, leaving 3.2 tons less carbon per hectare annually. Recently developed cultivars produced 70 % more grain in depositional soils and 30 % more in highly eroded soils than earlier cultivars. However, this increased grain yield came with a trade-off: carbon input into soil decreased by 32 % in eroded soils and 43 % in depositional soils. Simulations reveal recently developed cultivars are more sensitive to drying soils, which received 12 kg C ha^-1 less than those with earlier cultivars over the five years.