Cover crop effects on fibrous roots and growth of subsequent sugar beet

Abstract

Abstract Purpose Cover crops (CC) may increase root growth of the following main crop by improving the soil structure, however, the extent of this effect might depend on the CC species. This study aims at quantifying the effects of different CCs on sugar beet (SB; Beta vulgaris L.) fibrous roots and plant growth. Methods Two field trials were conducted near Göttingen, Central Germany, with SB after four CC treatments: fallow, oil radish, saia oat, and spring vetch, differing in biomass. SB root length density and biomass was analyzed to 60 cm soil depth in July, around 100 days after sowing. From June on, plants were sampled monthly to determine leaf and taproot biomass. CC biomass and SB residues were further analyzed for carbon content. Results SB root length density in 0–20 cm soil depth was increased by the CCs, particularly radish and oat, while in lower depths only non-significant differences were found. Differences between the CC treatments regarding SB leaf and taproot biomass were site-specific with increases in SB biomass after CCs at a site with high N supply, yet no effects on sugar yield were found for either site. Carbon input into the soil was significantly increased through CC cultivation by 47 to 85%. Conclusion CCs with different properties improved fibrous root and overall plant growth of SB to a different extent at sites with contrasting conditions. Future studies under diverse environmental conditions are needed to fully assess the potential benefits of CCs on following SB growth.