Estimating nitrogen budgets of Typha angustifolia by considering the regrowth shoot productivity and nitrogen content after harvesting aerial organs in different growing seasons |
| |
Authors: | Shamal Chandra Das Norio Tanaka |
| |
Institution: | (1) Graduate School of Science and Engineering, Saitama University, 255 Shimo-okubo, Sakura-ku, Saitama 338-8570, Japan |
| |
Abstract: | A dynamic model that includes regrowth after harvesting aerial shoots of an emergent macrophyte, Typha angustifolia L., was applied to evaluate the nitrogen (N) budget and the N uptake by the plant from sediment in Shibakawa Pond, Japan.
Under natural conditions (control/uncut stands), the analysis showed that the annual uptake of N from sediment was 26.6 gN/m2 and harvesting Typha shoots at their growth peak removed 29.0 gN/m2 from the system (142 days in summer). Harvesting in winter after weathering of leaves removed only 13.9 gN/m2. To evaluate the N budget considering regrowth shoot characteristics, three sets of harvesting experiments were done on 16
May, 8 July, and 5 August 2003. Our study revealed that May, July, and August harvesting removed 9.4, 21.9, and 16.3 gN/m2, respectively. Further, combining the first harvesting from spring to summer and the second harvesting in autumn (before
the start of senescence of regrowth shoots), the annual total N removals in stands cut in May and autumn and July and autumn
were 34.7 and 36.0 gN/m2, respectively—higher than that in stands cut in August and autumn (22.2 gN/m2) or that in uncut stands (13.9 gN/m2). At the same time, the amounts stored in rhizomes by stands cut in May and autumn, July and autumn, and August and autumn
were 9.1, 8.4, and 4.4 gN/m2, respectively, lower than that in uncut stands (18.8 gN/m2). Our results suggest that summer harvesting, especially in July to August, improves N removal efficiency and decreases the
translocation of N from primary shoots to rhizomes, which is important for the sustainable management of Typha-dominated wetlands. Combined summer and autumn harvests further increase the removal efficiency but drastically reduce the
storage of N. This might be useful when we need to control the plants properly. |
| |
Keywords: | Emergent macrophytes Growth dynamic model Plant uptake Sustainable management Wastewater treatment |
本文献已被 SpringerLink 等数据库收录! |
|