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High nitrogen : phosphorus ratios reduce nutrient retention and second‐year growth of wetland sedges
Author(s) -
Güsewell Sabine
Publication year - 2005
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2005.01320.x
Subject(s) - carex , nutrient , phosphorus , growing season , biomass (ecology) , wetland , agronomy , nitrogen , biology , zoology , botany , chemistry , ecology , organic chemistry
Summary• Shifts from nitrogen (N)‐ to phosphorus (P)‐limited growth due to high N deposition may alter the functioning of wetland vegetation. This experiment tested how N vs P deficiency affects the growth and nutrient use of wetland sedges. • Five wetland Carex species were grown at nine N : P supply ratios (0.6–405) with two absolute levels of N and P. Biomass and nutrient concentrations were determined after one and two growing seasons. • Shoot biomass was maximal at N : P supply ratios of 15–26 after one season but 5–15 after two seasons. Photosynthesis after the first season, second‐year growth, leaf longevity, and the fraction of nutrient supply retained by plants over two seasons were all negatively related to N : P supply ratios, with small effects of absolute supply. The five Carex species responded similarly to N : P ratios but differed in nutrient resorption efficiency and biomass allocation. • Plants treated with high N : P ratios appeared to lose nutrients below ground. Such losses may reduce plant performance in P‐limited wetlands affected by high N deposition.