Please use this identifier to cite or link to this item: https://repositorio.inpa.gov.br/handle/1/19360
Title: Nutrient dynamics of the highly productive C4 macrophyte Echinochloa polystachya on the Amazon floodplain
Authors: Piedade, Maria Teresa Fernandez
Junk, Wolfgang Johannes
Long, Stephen Patrick
Keywords: Echinochloa Polystachya
Echinochloa Polystachya
Poaceae
Aquatic Macrophyte
Floodplain
Nutrient Dynamics
Brazil, Amazonia
South America, Amazonia
Issue Date: 1997
metadata.dc.publisher.journal: Functional Ecology
metadata.dc.relation.ispartof: Volume 11, Número 1, Pags. 60-65
Abstract: 1. Echinochloa polystachya forms extensive monotypic stands on the lower levels of the Amazon floodplains. During its annual growth cycle c. 100t (dry mass) ha-1 of biomass is formed as the floodplain is being submerged (December-September) and a phase of death and decomposition occurs when the water has retreated (October-November). This study examines the mineral nutrient dynamics of this plant and its potential significance to the nutrient status of the floodplain. 2. Echinochloa polystachya was sampled monthly from a study site in the central Amazon. N, P and K contents for different plant organs were determined and net uptake calculated from concurrent measurements of dry matter production and turnover. 3. Leaf N, P and K contents were c. 20, 1.7 and 19 g kg-1, values typical of nutrient-replete stands of C4 plants. Stem concentrations were c. 12% of those of the leaves. Net N and P uptake followed the rise in the river level, whilst K appeared independent of water level. 4. The vegetation accumulated 377, 51 and 1136 kg ha-2 of N, P and K, respectively, during the growth phase. Over a possible 5000 km2 of these stands in the Varzea, this represents a massive sequestration of nutrients in the flood phase and a high release during the following low-water period. It is suggested that the E. polystachya stands could have a role in maintaining the nutrient status of the Amazon floodplain.
metadata.dc.identifier.doi: 10.1046/j.1365-2435.1997.00066.x
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