
TY  - JOUR
A1  - Hocking, P.J. 
T1  - Seasonal dynamics of production, and nutrient accumulation and cycling by <I>Phragmites asutralis</I> (Cav.) Trin. <I>ex</I> Stuedel in a nutrient-enriched swamp in Inland Australia. I. Whole Plants
JF  - Marine and Freshwater Research
JO  - Mar. Freshwater Res.
Y1  - 1989
VL  - 40
IS  - 5
SP  - 421
EP  - 444
KW  - 
UR  - https://doi.org/10.1071/MF9890421 
N2  - A study was made of the seasonal changes in dry matter production and patterns of nutrient accumulation by Phragmites australis in a nutrient-enriched swamp in inland Australia. The density of live shoots was highest (224 m-2) in October, but the peak standing crop of live shoots (9890 g m-2) occurred in early May. Peak below-ground biomass (21 058 g m-2) occurred in early August. Rhizome biomass constituted 75% of the below-ground biomass, and showed a distinct seasonal pattern. Net annual above-ground primary production (NAAP), estimated by the maximum-minimum method, was 9513 g m-2. Correction for shoot mortality and leaf shedding before, and production after, the maximum standing crop was attained increased NAAP to 12 898 g m-2. Whole plant production estimated by the maximum-minimum method was 9960 g m-2, and the corrected estimate was 14 945 g m-2. A model of dry-matter production indicated that translocation of carbohydrate from rhizomes could have provided 33% of the dry matter of shoots. About 23% of the dry matter of shoots was redistributed to below-ground organs during senescence. Concentrations of N, P, K, S, Cl and Cu declined, but concentrations of Ca, Mg, Na, Fe and Mn increased as shoots aged. Concentrations of N, P and Zn in rhizomes reached maxima in winter, and decreased in spring. Rhizomes usually contained the greatest quantity of a nutrient in the whole plant, and roots usually had less than 25% of the total plant content. There were seasonal fluctuations in the quantities of N, P, K, Zn and Cu in rhizomes. Nutrient accumulation by live shoots was underestimated by 22-55% using the maximum-minimum method. Nutrient budgets showed considerable internal cycling of N, P, K, S and Cu from rhizomes to developing shoots in spring, and from senescing shoots to rhizomes during autumn and winter. 
ER  -

