Emergence and growth performance of Bolboschoenus planiculmis varied in response to water level and soil planting depth: Implications for wetland restoration using tuber transplantation

As a common plant in the Momoge National Nature Reserve (MNNR), China, Bolboschoenus planiculmis has been acknowledged as a key species in Siberian Crane (Grus leucogeranus) habitat by providing food for this migratory waterfowl. Water shortage and salinization have severely impacted B. planiculmis vegetation in this area. In order to restore the degraded B. planiculmis wetlands, tuber transplantation is tentatively used in MNNR. However, the effects of the abiotic factors on tuber emergence and growth of B. planiculmis are poorly understood. In this study, emergence, growth, biomass accumulation and tuber reproduction were investigated experimentally using four water levels (5 cm below soil surface, 0 cm, 10 cm and 20 cm above soil surface) and three soil planting depths (5 cm, 10 cm and 15 cm). Results indicated that emergence, growth and production were closely related with the water level and planting depth. Increasing the water level and planting depth generally decreased the emergence rate and speed of planted tubers. The water table at 5 cm below soil surface significantly increased emergence rate and emergence speed of tubers planted at 5 cm soil depth. Water table at soil surface and 10 cm above soil surface facilitated subsequent growth, biomass accumulation and tuber reproduction of B. planiculmis at soil depth of 5 cm. In addition, planting tubers at this depth increased root/shoot ratio across the four water levels. Therefore, the tuber transplanting method can be selectively ameliorated to promote the plant establishment, plant growth and productivity of B. planiculmis. Results of this study provide technical support for the restoration of B. planiculmis wetland and the improvement in the quality of Siberian Crane habitat.