Effects of CO2 and nitrogen fertilization on vegetation and soil nutrient content in juvenile ponderosa pine
In: Plant and soil, Jg. 190 (1997), Heft 1, S. 29-40
Online
academicJournal
- print, 34 ref
Zugriff:
This paper summarizes the data on nutrient uptake and soil responses in opentop chambers planted with ponderosa pine (Pinus ponderosa Laws.) treated with both N and CO2. Based upon the literature, we hypothesized that 1) elevated CO2 would cause increased growth and yield of biomass per unit uptake of N even if N is limiting, and 2) elevated CO2 would cause increased biomass yield per unit uptake of other nutrients only by growth dilution and only if they are non-limiting. Hypothesis 1 was supported only in part: there were greater yields of biomass per unit N uptake in the first two years of growth but not in the third year. Hypothesis 2 was supported in many cases: elevated CO2 caused growth dilution (decreased concentrations but not decreased uptake) of P, S, and Mg. Effects of elevated CO2 on K, Ca, and B concentrations were smaller and mostly non-significant. There was no evidence that N responded in a unique manner to elevated CO2, despite its unique role in rubisco. Simple growth dilution seemed to explain nutrient responses in almost all cases. There were significant declines in soil exchangeable K+, Ca2+, Mg2+ and extractable P over time which were attributed to disturbance effects associated with plowing. The only statistically significant treatment effects on soils were negative effects of elevated CO2 on mineralizeable N and extractable P, and positive effects of both N fertilization and CO2 on exchangeable Al3+. Soil exchangeable K+, Ca2+, and Mg2+ pools remained much higher than vegetation pools, but extractable P pools were lower than vegetation pools in the third year of growth. There were also large losses of both native soil N and fertilizer N over time. These soil N losses could account for the observed losses in exchangeable K+, Ca2+, Mg2+ if N was nitrified and leached as NO3-.
Titel: |
Effects of CO2 and nitrogen fertilization on vegetation and soil nutrient content in juvenile ponderosa pine
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Autor/in / Beteiligte Person: | JOHNSON, D. W ; BALL, J. T ; WALKER, R. F |
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Zeitschrift: | Plant and soil, Jg. 190 (1997), Heft 1, S. 29-40 |
Veröffentlichung: | Dordrecht: Springer, 1997 |
Medientyp: | academicJournal |
Umfang: | print, 34 ref |
ISSN: | 0032-079X (print) |
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