Effects of Root-Cutting Treatment on Biomass, Photosynthetic Characteristics, and Soil Nutrients in Jerusalem Artichoke

Helianthus tuberosus L. tubers are the primary part utilized by humans for bioenergy and bioproduct production. Therefore, achieving high tuber yield is a core issue in Jerusalem artichoke cultivation and management. In this study, red-skinned Jerusalem artichoke was used as an experimental material. Under field conditions from 2022 to 2023, different root-cutting treatments were established to investigate their effects on Jerusalem artichoke biomass, photosynthetic characteristics, and rhizosphere (non-rhizosphere) soil nutrient content, aiming to provide a theoretical basis for high-yield cultivation of Jerusalem artichoke. During the vegetative growth stage (70–75 days after planting), a “vertical cutting method” was applied; centered on the plant, vertical cuts were made through the horizontal root system at radii of 20 cm, 30 cm, 40 cm, and 50 cm to implement root-cutting treatments. The total biomass, underground biomass, tuber yield and root/shoot ratio of Jerusalem artichoke increased by 11.59–25.97%, 15.77–46.33%, 7.69–49.09% and 11.72–62.69%, respectively. The tuber yield was greatest under D1 (20 cm) (0.94 kg·plant−1 and 0.98 kg·plant−1). On the 7th and 15th days after root breakage, the photosynthetic characteristics and transpiration rate of the Jerusalem artichoke gradually increased with increasing root-cutting radius and were lower than those of the control. On the 21st day after the root-cutting treatment, the photosynthetic characteristics and transpiration rate of the Jerusalem artichoke plants gradually decreased with increasing root-cutting radius and were greater than those of the control plants. The water use efficiency of Jerusalem artichoke increased with increasing root-cutting radius. The contents of C, N, P, available phosphorus, alkali-hydrolyzed nitrogen, nitrate nitrogen showed that proper root-cutting can increase tuber yield of Jerusalem artichoke and improve rhizosphere soil nutrients.