Abstract: In this study, six dominant plant species, including Phragmites australis, Triarrhena lutarioriparia, Zizania latifolia, Carex cinerascens, Carex Argyi and Polygonum hydropiper, were selected in Nanji Wetlands National Nature Reserve in Poyang Lake. Subsequently, mature and senescent leaves were sampled for analyzing N and P concentrations at biomass peaking and the end of growing season, respectively. The objective of this study was to clarify the characteristics of N and P resorption of the six dominant plant species in Poyang Lake wetlands. The results showed that the N resorption efficiency (NRE) of the six plant species ranged from 8.2% to
46.6%, whereas the P resorption efficiency (PRE) varied from 18.9% to 44.5%. Among the six plant species, C. cinerascens had the minimum NRE and PRE. Moreover, the mean NRE and PRE were 41.3% and 38.5% for emergent plants, but 19.9% and 26.0% for hydromorphic plants, respectively. NRE and PRE were positively correlated with N and P concentrations in mature leaves. In addition, NRE was positively correlated with N∶P ratio in mature leaves. According to their nutrient resorption proficiency, the six plant species in the Poyang Lake wetlands could be recognized as low N resorption plants.

Key words: straw potassium, substitute potassium, rice, nutrient absorption, tobacco straw returning