Nitrogen limitation and growth response to CO{sub 2} in ponderosa pine

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Bulletin of the Ecological Society of America

OSTI ID:107108

Johnson, D W; Henderson, P ^[1]; Walker, R F ^[2]

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1. Desert Research Institute, Reno, NV (United States)
2. Univ. of Nevada, Reno, NV (United States); and others

Ponderosa pine (Pinus ponderosa) was grown from seed and subjected to three levels of CO{sub 2} (370,525, and 700 {mu}l/ l{sup {minus}1}) and three levels of N (0, 10, and 20 g N m{sup {minus}2} yr{sup {minus}1}) for three years in open top chambers. Both N and CO{sub 2} produced a positive growth response, and there was a growth response to CO{sub 2} without fertilization. This growth increase was accompanied by increased N uptake with elevated CO{sub 2}; the commonly-observed reduction in tissue N concentration was insufficient to allow a significant growth response without additional N uptake. Detailed and exhaustive analyses of both bulk soil and rhizosphere soil revealed no growth response without additional N uptake. Detailed and exhaustive analyses of both bulk soil and rhizosphere soil revealed no effect of elevated CO{sub 2} on soil N mineralization rate. Thus, the growth response to elevated CO{sub 2} with suboptimal N was facilitated by greater root biomass and exploration of the soil for available N supplies. Root biomass was disproportionately greater in trees treated with elevated CO{sub 2}. Results of this in combination with previous pot studies show that N limitation is a continuum rather than an on/off situation, and thus N limitation constraints upon CO{sub 2} response varies continuously from complete limitation at very low N to no limitation at high N.

• OSTI ID: 107108
• Report Number(s): CONF-9507129--
• Journal Information: Bulletin of the Ecological Society of America, Journal Name: Bulletin of the Ecological Society of America Journal Issue: 3 Vol. 76; ISSN BECLAG; ISSN 0012-9623
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOCHEMISTRY
BIOLOGICAL EFFECTS
CARBON DIOXIDE
NITROGEN
PINES
PLANT GROWTH
UPTAKE