Asparagus (Asparagus officinalis L.) Root Distribution: Cultivar Differences in Mature Plantings

Annual plant growth patterns and seasonal conditions have both been shown to influence asparagus (Asparagus officinalis L.) root development over time. Root biomass and distribution changes in mature asparagus cultivars are herein illustrated and described. Asparagus root length density and biomass were estimated from soil cores using a systematic field sampling approach each spring. Soil cores (0.9 m deep) were divided into 0.15 m lengths and fleshy roots collected from the soil. Root length density and dry weights were determined and root distribution maps generated from collected data. As asparagus plantings matured, the sampling year had a significant influence on root development. Fleshy roots grew deeper into the soil each year but the majority of roots of Atlas, Guelph Millennium, and Jersey Giant were found in the upper 60 cm of the soil profile. For the three cultivars evaluated, minor differences in root length and root weight occurred. By Year 6, Atlas showed a decrease in root length and weight when compared to Guelph Millennium and Jersey Giant. While spear yield differences between the varieties were not significant, Atlas tended to produce more very large and large spears compared to Guelph Millennium and Jersey Giant. These results increase our understanding of asparagus root development.