Abstract: The ecological stoichiometry of root, stem and leaf of Phragmites australis in different habitats of Keriya River of the southern marginal zone of Tarim Basin, Xinjiang was studied, to explore the effects of habitats and organs on stoichiometry. The results showed that the mean concentrations of C, N and P in P. australis organs were in order of leaves > stems > roots, the C∶N and C∶P ratios were in order of roots > stems > leaves, whereas the N∶P ratio was in order of leaves > stems > roots. The concentrations of C, N, P and their stoichiometric ratios in roots, stems and leaves differed with habitat. The concentrations of C in root, stem and leaf were significantly higher in riverbank than in oasis and desert. Stem N concentration was significantly lower in desert than in riverbank and oasis, while the concentrations of N in leaf and root were not significantly different among the three habitats. Leaf P concentration in oasis was significantly higher than in desert, and the concentrations of P in stem and root were significantly higher in riverbank than in oasis and desert. There was no significant difference in C∶N ratio among root, stem and leaf. The C∶P ratios in stem and root differed between riverbank and desert, while the ratio of N∶P did not differ among the three habitats and was less than 14, which indicated that the growth of P. australis was mainly limited by N. The N concentration was positively correlated with the P concentration, indicating a consistent demand of N and P during P. australis growth. According to the factorial analysis of GLM, we concluded that the C and N concentrations and C∶N and N∶P ratios were mainly affected by the organs, while the P concentration and C∶P ratio were mainly determined by the habitats.

Key words: arid land, cotton field, nitrous oxide, desert soil, plastic mulch drip irrigation, urease inhibitor, nitrification inhibitor, controlled-release fertilizer