J. T. Ball

Michigan State University, East Lansing, Michigan, United States

Are you J. T. Ball?

Claim your profile

Publications (38)87.75 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We conducted a 4-year study of juvenile Pinus ponderosa fine root (< or =2 mm) responses to atmospheric CO2 and N-fertilization. Seedlings were grown in open-top chambers at three CO2 levels (ambient, ambient+175 mumol/mol, ambient+350 mumol/mol) and three N-fertilization levels (0, 10, 20 g m(-2) year(-1)). Length and width of individual roots were measured from minirhizotron video images bimonthly over 4 years starting when the seedlings were 1.5 years old. Neither CO2 nor N-fertilization treatments affected the seasonal patterns of root production or mortality. Yearly values of fine-root length standing crop (m m(-2)), production (m m(-2) year(-1)), and mortality (m m(-2) year(-1)) were consistently higher in elevated CO2 treatments throughout the study, except for mortality in the first year; however, the only statistically significant CO2 effects were in the fine-root length standing crop (m m(-2)) in the second and third years, and production and mortality (m m(-2) year(-1)) in the third year. Higher mortality (m m(-2) year(-1)) in elevated CO2 was due to greater standing crop rather than shorter life span, as fine roots lived longer in elevated CO2. No significant N effects were noted for annual cumulative production, cumulative mortality, or mean standing crop. N availability did not significantly affect responses of fine-root standing crop, production, or mortality to elevated CO2. Multi-year studies at all life stages of trees are important to characterize belowground responses to factors such as atmospheric CO2 and N-fertilization. This study showed the potential for juvenile ponderosa pine to increase fine-root C pools and C fluxes through root mortality in response to elevated CO2.
    Oecologia 06/2006; 148(3):517-25. · 3.01 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The effects of elevated CO2 (ambient, +175, and +350 μl l−1) and nitrogen fertilization (0, 100, and 200 kg N ha−1 yr−1 as ammonium sulfate) on C and N accumulations in biomass and soils planted with ponderosa pine (Pinus ponderosa Laws) over a 6-year study period are reported. Both nitrogen fertilization and elevated CO2 caused increases in C and N contents of vegetation over the study period. The pattern of responses varied over time. Responses to CO2 decreased in the +175 μl l−1 and increased in the +350 μl l−1 after the first year, whereas responses to N decreased after the first year and became non-significant by year six. Foliar N concentrations were lower and tree C:N ratios were higher with elevated CO2 in the early years, but this was offset by the increases in biomass, resulting in substantial increases in N uptake with elevated CO2. Nitrogen budget estimates showed that the major source of the N for unfertilized trees, with or without elevated CO2, was likely the soil organic N pool. There were no effects of elevated CO2 on soil C, but a significant decrease in soil N and an increase in soil C:N ratio in year six. Nitrogen fertilization had no significant effect on tree C:N ratios, foliar N concentrations, soil C content, soil N content, or soil C:N ratios. There were no significant interactions between CO2 and N treatments, indicating that N fertilization had no effect on responses to CO2 and that CO2 treatments had no effect on responses to N fertilization. These results illustrate the importance of long-term studies involving more than one level of treatment to assess the effects of elevated CO2.
    Biogeochemistry 01/2006; 77(2):157-175. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Previous modelling exercises and conceptual arguments have predicted that a reduction in biochemical capacity for photosynthesis (Aarea) at elevated CO2 may be compensated by an increase in mesophyll tissue growth if the total amount of photosynthetic machinery per unit leaf area is maintained (i.e. morphological upregulation). The model prediction was based on modelling photosynthesis as a function of leaf N per unit leaf area (Narea), where Narea = Nmass×LMA. Here, Nmass is percentage leaf N and is used to estimate biochemical capacity and LMA is leaf mass per unit leaf area and is an index of leaf morphology. To assess the relative importance of changes in biochemical capacity versus leaf morphology we need to control for multiple correlations that are known, or that are likely to exist between CO2 concentration, Narea, Nmass, LMA and Aarea. Although this is impractical experimentally, we can control for these correlations statistically using systems of linear multiple-regression equations. We developed a linear model to partition the response of Aarea to elevated CO2 into components representing the independent and interactive effects of changes in indexes of biochemical capacity, leaf morphology and CO2 limitation of photosynthesis. The model was fitted to data from three pine and seven deciduous tree species grown in separate chamber-based field experiments. Photosynthetic enhancement at elevated CO2 due to morphological upregulation was negligible for most species. The response of Aarea in these species was dominated by the reduction in CO2 limitation occurring at higher CO2 concentration. However, some species displayed a significant reduction in potential photosynthesis at elevated CO2 due to an increase in LMA that was independent of any changes in Narea. This morphologically based inhibition of Aarea combined additively with a reduction in biochemical capacity to significantly offset the direct enhancement of Aarea caused by reduced CO2 limitation in two species. This offset was 100% for Acer rubrum, resulting in no net effect of elevated CO2 on Aarea for this species, and 44% for Betula pendula. This analysis shows that interactions between biochemical and morphological responses to elevated CO2 can have important effects on photosynthesis.
    Plant Cell and Environment 01/2002; 22(9):1109 - 1119. · 5.91 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Summary Studies have suggested that more carbon is fixed due to a large increase in photosynthesis in plant–soil systems exposed to elevated CO2 than could subsequently be found in plant biomass and soils –- the locally missing carbon phenomenon. To further understand this phenomenon, an experiment was carried out using EcoCELLs which are open-flow, mass-balance systems at the mesocosm scale. Naturally occurring 13C tracers were also used to separately measure plant-derived carbon and soil-derived carbon. The experiment included two EcoCELLs, one under ambient atmospheric CO2 and the other under elevated CO2 (ambient plus 350 L L− 1). By matching carbon fluxes with carbon pools, the issue of locally missing carbon was investigated. Flux-based net primary production (NPPf) was similar to pool-based primary production (NPPp) under ambient CO2, and the discrepancy between the two carbon budgets (12 g C m− 2, or 4% of NPPf) was less than measurement errors. Therefore, virtually all carbon entering the system under ambient CO2 was accounted for at the end of the experiment. Under elevated CO2, however, the amount of NPPf was much higher than NPPp, resulting in missing carbon of approximately 80 g C m− 2 or 19% of NPPf which was much higher than measurement errors. This was additional to the 96% increase in rhizosphere respiration and the 50% increase in root growth, two important components of locally missing carbon. The mystery of locally missing carbon under elevated CO2 remains to be further investigated. Volatile organic carbon, carbon loss due to root washing, and measurement errors are discussed as some of the potential contributing factors.
    Global Change Biology 01/2000; 6(1):99-109. · 8.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Atmospheric CO2 enrichment effects on growth, nutrition, and water relations of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were investigated in a field study of 5 years duration which included a soil N fertility variable in order to assess interactions of CO2 and N on tree responses. Open-top chambers permitted creation of atmospheres with 700 μl l−1, 525 μl l−1, or ambient CO2 concentrations. Trees were reared from seed in a mid elevation Sierra Nevada forest soil with a total N concentration of 856 μg g−1 or in soil amended with sufficient (NH4)2SO4 to increase total N by 100 μg g−1 or 200 μg g−1. The intermediate CO2 treatment within the intermediate N treatment was omitted from the study. Height and diameter measurements at the conclusions of each of the five growing seasons revealed significant growth enhancement by atmospheric enrichment, initially more pronounced in 525 μl l−1 than in 700 μl l−1 CO2. Final measurements indicated that the twice-ambient atmosphere ultimately proved the most stimulatory, however, but the magnitude of the growth responses to elevated CO2 was somewhat dependent on soil N availability throughout the study. Foliar analysis revealed reductions in N, P, and S concentrations during the second season and that of Mg in the third season in the above-ambient CO2 treatments, while P was increased by high CO2 in high soil N but decreased by high CO2 in low N during the third season. Among micronutrients, foliar Fe was elevated in high CO2, a response that also extended to Al, while Mn and B concentrations were reduced in this atmosphere, but significant treatment effects on micronutrients and Al were found in the second season only and were evident primarily in low soil N. During the fourth growing season, foliar N was initially higher but then later become lower in the above-ambient atmospheres. Predawn and midday measurements of xylem water potential made at intervals during the fifth season indicated substantial variability in responses to treatment, but increased moisture stress in trees reared in the enriched atmospheres was periodically evident.
    Forest Ecology and Management 01/2000; · 2.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: elevated CO2 (Allen et al., 2000) but no statistically significant differences in fine root production, microbial Soil C sequestration in predicted, future elevated CO2 environ- biomass, or plant chemistry. Growth in elevated CO2 ments will be important to atmospheric CO2 levels, soil tilth, and fertility. An elevated CO2 study with ponderosa pines (Pinus pon- can lead to changed plant species composition and litter derosa Laws) grown in chambers produced above ground vegetation quality and quantity (Oene et al., 1999). This together with a d 13 Co f244‰ and roots with 242‰. This together with carbon with changes in other constituents can alter decomposi- dating made it possible to follow soil C dynamics. Fifty percent of the tion of litter and C cycling back to the atmosphere California upland soil C, resistant to acid hydrolysis, was designated as (Strain and Thomas, 1992). Increases in N can act the resistant fraction. Carbon dating showed the mean residence times through enhanced plant growth, changes in litter quality, of this fraction to be 400 to 1500 yr greater than the total soil C for and either positive or negative alteration of in situ de- the horizons sampled. Young ponderosa pines grown in CO2 chambers composition rates (Fogg, 1988). The response of trees to produced negligible leaf litter. There were 32% more roots in the elevated atmospheric C and N fertilization is especially presence of either added N or double CO2 but 77% more in the presence of both. Root-derived soil C was equivalent to 10% of the important in that forests are considered to be major root C after the 6-yr growth period. Analysis of laboratory CO2 evolu- potential C sinks in global change scenarios (Schimel, tion during extended incubation showed the active soil C pool repre- 1995; Fan et al., 1998). Atmospheric N may enhance sented 1 to 2% of the soil C with a field-equivalent mean residence both tree growth and soil C sequestration; it can also time (MRT) of 24 to 53 d. The slow pool represented 46 to 52% of contribute to forest decline (Nadelhoffer et al., 1999). the C with MRT of 24 to 67 yr depending on treatment and soil depth. Elevated CO2 concentration in the soil atmosphere has Analysis of the 13 CO2 label during incubation from the elevated CO2 resulted in increased ecosystem C uptake but also has treatments, showed the root-derived 13
    Soil Science Society of America Journal - SSSAJ. 01/2000; 64(6).
  • Source
    D. W. Johnson, W. Cheng, J. T. Ball
    [Show abstract] [Hide abstract]
    ABSTRACT: The effects of six years treatment with elevated [CO2] (350, 525, and 700 μl l-1) and nitrogen (N) (0, 10, and 20 g N m-2 yr-1) on soils, soil solution, and CO2 efflux in an open-top chamber study with ponderosa pine (Pinus ponderosa Laws.) are described. The clearest [CO2] effect was in year 6, when a pattern of lower soil N concentration and higher C/N ratio with elevated [CO2] emerged. Statistically significant effects of elevated [CO2] on soil total C, extractable P, exchangeable Mg2+, exchangeable Ca2+, base saturation, and soil solution HCO3 - and NO3 - were also found in various treatment combinations and at various times; however, these effects were inconsistent among treatments and years, and in many cases (P, Mg2+, Ca2+, base saturation) reflected pre-treatment differences. The use of homogenized buried soil bags did not improve the power to detect changes in soil C and N or help resolve the inconsistencies in soil C patterns. Nitrogen fertilization had the expected negative effects on exchangeable Ca2+, K+, and Mg2+ in year 6, presumably because of increased NO3 - leaching, but had no consistent effect on soil C, N, or extractable P.
    Plant and Soil 01/2000; 224(1):99-113. · 3.24 Impact Factor
  • Source
    D. W. Johnson, W. Cheng, J. T. Ball
    [Show abstract] [Hide abstract]
    ABSTRACT: Naturally senesced needles from ponderosa pine (Pinus ponderosa Dougl.), grown from seed in open-top chambers under three levels of CO2 (350, 525 and 700 μl l-1) and three levels of N fertilization (0, 10 and 20 g N m-2 yr-1), were used in a field litterbag decomposition study and in a laboratory study on potential microbial and nonmicrobial N immobilization. The litterbag studies revealed no statistically significant effects of either CO2 or N treatment on mass loss, N concentration, or N content over a 26-month period. The laboratory study of potential 15N immobilization revealed no statistically significant effects of CO2 or N treatment on either total or microbial immobilization. Elevated (CO2) did have a significant negative effect on nonmicrobial immobilization, however. Natural abundance of 15N was significantly greater with elevated (CO2) in both live and naturally senesced needles under all N treatments. This pattern combined with 15N natural abundance in soils suggests that saplings grown under elevated (CO2) were either taking up more N from surface horizons or from a more recalcitrant soil N pool in either horizon.
    Plant and Soil 01/2000; 224(1):115-122. · 3.24 Impact Factor
  • Source
    David T. Tissue, Kevin L. Griffin, J. Timothy Ball
    [Show abstract] [Hide abstract]
    ABSTRACT: Photosynthesis of tree seedlings is generally enhanced during short-term exposure to elevated atmospheric CO(2), but longer-term photosynthetic responses are often more variable because they are affected by morphological, biochemical and physiological feedback mechanisms that regulate carbon assimilation to meet sink demand. To examine biochemical and morphological factors that might regulate the long-term photosynthetic response of field-grown trees to elevated CO(2), we grew ponderosa pine (Pinus ponderosa Dougl. ex Laws.) trees in open-top chambers for six years in native soil at ambient CO(2) (35 Pa) and elevated CO(2) (70 Pa) at a site near Placerville, CA. Trees were well watered and exposed to natural light and ambient temperature. At the end of the sixth growing season at elevated CO(2), net photosynthesis was enhanced 53%, despite reductions in photosynthetic capacity. The positive net photosynthetic response to elevated CO(2) reflected greater relative increases in Rubisco sensitivity compared with the decreases resulting from biochemical adjustments. Analyses of net photosynthetic rate versus internal CO(2) partial pressure curves indicated that reductions in photosynthetic capacity in response to elevated CO(2) were the result of significant reductions in maximum photosynthetic rate (20%), Rubisco carboxylation capacity (36%), and electron transport capacity (21%). Decreased photosynthetic capacity was accompanied by reductions in various photosynthetic components, including total chlorophyll (24%), Rubisco protein content (38%), and mass-based leaf nitrogen concentration (14%). Net photosynthesis was unaffected by morphological adjustments because there was no change in leaf mass per unit area at elevated CO(2). An apparent positive response of photosynthetic adjustment in the elevated CO(2) treatment was the redistribution of N within the photosynthetic system to balance Rubisco carboxylation and electron transport capacities. We conclude that trees, without apparent limitations to root growth, may exhibit photosynthetic adjustment responses in the field after long-term exposure to elevated CO(2).
    Tree Physiology 05/1999; 19(4_5):221-228. · 2.85 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Estimation of leaf photosynthetic rate (A) from leaf nitrogen content (N) is both conceptually and numerically important in models of plant, ecosystem, and biosphere responses to global change. The relationship between A and N has been studied extensively at ambient CO2 but much less at elevated CO2. This study was designed to (i) assess whether the A–N relationship was more similar for species within than between community and vegetation types, and (ii) examine how growth at elevated CO2 affects the A–N relationship. Data were obtained for 39 C3 species grown at ambient CO2 and 10 C3 species grown at ambient and elevated CO2. A regression model was applied to each species as well as to species pooled within different community and vegetation types. Cluster analysis of the regression coefficients indicated that species measured at ambient CO2 did not separate into distinct groups matching community or vegetation type. Instead, most community and vegetation types shared the same general parameter space for regression coefficients. Growth at elevated CO2 increased photosynthetic nitrogen use efficiency for pines and deciduous trees. When species were pooled by vegetation type, the A–N relationship for deciduous trees expressed on a leaf-mass basis was not altered by elevated CO2, while the intercept increased for pines. When regression coefficients were averaged to give mean responses for different vegetation types, elevated CO2 increased the intercept and the slope for deciduous trees but increased only the intercept for pines. There were no statistical differences between the pines and deciduous trees for the effect of CO2. Generalizations about the effect of elevated CO2 on the A–N relationship, and differences between pines and deciduous trees will be enhanced as more data become available.
    Global Change Biology 01/1999; 5:331-346. · 8.22 Impact Factor
  • Source
    Global Change Biol. 01/1999; 5:331-346.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Individual and interactive effects of atmospheric CO2 enrichment and soil N and P fertility on above- and below-ground growth and mycorrhizal colonization of juvenile ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were examined. Seedlings were grown from seed in atmospheres with 700 μl l−1, 525 μl l−1, or ambient CO2 concentrations. High and low soil N treatments were created by adding sufficient (NH4)2SO4 to an infertile soil mixture to establish total N concentrations of 500 μg g−1 and 400 μg g−1, respectively, while high and low P treatments consisted of 68 μg g−1 and 43 μg g−1 concentrations, respectively, of extractable P created by additions of CaHPO4. All seedlings were inoculated with the mycobiont Pisolithus tinctorius (Pers.) Coker and Couch shortly after emergence. Three whole-seedling harvests at four month intervals permitted assessment of treatment effects on shoot and root growth and ectomycorrhizal development. Initially, 525 μl l−1 CO2 and high N and P were all influential factors in above-ground growth, with each of these treatments increasing shoot weight while the latter increased height, diameter and volume. Stimulation of root growth was evident in dry weight and length measurements at the first harvest, with N and P main treatment effects again evident, but the response to elevated CO2 was most pronounced in the 700 μl l−1 atmosphere. After eight months, soil P was of little consequence above- or below-ground, but high N increased shoot dimensions, volume, and weight and root weight and length. Furthermore, the 525 μl l−1 CO2 treatment emerged as the dominant stimulatory atmosphere both above- and below-ground, as seedlings grown in intermediate CO2 exhibited the largest shoot diameters, greatest shoot and root weights, and the longest root systems at the second harvest. At the final harvest, interactive effects of 525 μl l−1 CO2 and high N were prominent, as this treatment combination produced the largest shoot dimensions, volume and weight, and the greatest root volume and coarse and fine root weights. Intermediate CO2 also produced the longest root systems after 12 months. Shoot/root ratios were lowered by growth in 700 μl l−1 CO2 after four months and by both enriched atmospheres after eight months, but this effect was no longer evident at the final harvest. Greater numbers of mycorrhizae were formed by seedlings grown in 700 μl l−1 CO2 after four months and by those grown in 525 μl l−1 CO2 after eight months. Both enriched atmospheres increased mycorrhizal counts after 12 months, and seedlings grown in high CO2 and low N exhibited the highest percentage of total root system length colonized at the final harvest as well. Overall, these results indicate that CO2 enrichment stimulates shoot and root growth of juvenile ponderosa pine, a response dependent on soil N rather than P availability, and that the magnitude of the growth increase is greater in 1.5× ambient than in 2× ambient CO2.
    Forest Ecology and Management 09/1998; 109:9-20. · 2.77 Impact Factor
  • Early Human Development 07/1998; 51(3). · 2.02 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Interactive effects of elevated atmospheric CO2 and soil N fertility on above- and below-ground growth, mycorrhizal colonization, and water relations of juvenile ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were investigated. One-year-old seedlings were planted in undisturbed field soil within open-top chambers which permitted creation of atmospheres with 700 μl l−1, 525 μl l−1, or ambient CO2 concentrations. High and medium soil N treatments were imposed by incorporating sufficient (NH4)2SO4 to increase total N by 200 μg g−1 and 100 μg g−1, respectively, while unamended soil, which had a total N concentration of approximately 900 μg g−1, constituted the low N treatment. Following each of two consecutive field growing seasons, whole seedlings of every combination of CO2 and N treatment were harvested to permit assessment of shoot and root growth and quantification of ectomycorrhizal development. Late in the second growing season, a simulated drought episode was imposed by withholding irrigation during which predawn and midday xylem water potential and soil water potential were measured. The initial harvest revealed that coarse and fine root weights were increased by CO2 enrichment during the first growing season. This result was most apparent in the 525 μl l−1 CO2 treatment and high soil N, which produced the greatest root volume as well. Shoot/root ratio decreased with increasing CO2 at the first harvest. After two growing seasons, elevated CO2 increased seedling diameter, shoot and root volume, and shoot and coarse root weight, again most prominently in high N. Unlike the initial results, however, stimulation of seedling growth by the 700 μl l−1 CO2 atmosphere exceeded that in 525 μl l−1 CO2 after two growing seasons, and shoot/root ratio was unaffected by either CO2 or N. At both harvests, seedlings grown in the enriched atmospheres generally had higher mycorrhizal counts and greater percentages of colonized root length, but differences among treatments in ectomycorrhizal development were nonsignficant regardless of quantification method. During the imposed drought episode, xylem water potential of seedlings grown in elevated CO2 descended below that of seedlings grown in the ambient atmosphere as soil water potential decreased, most notably in the predawn measurements. These results suggest that CO2 enrichment stimulates shoot and root growth of juvenile ponderosa pine under field conditions, a response somewhat dependent on soil N availability. However, below-ground growth is not increased proportionally more than that above ground, which may predispose this species to greater stress when soil water is limited.
    Forest Ecology and Management 03/1998; 102(1):33–44. · 2.77 Impact Factor
  • Source
    Journal of Environmental Quality - J ENVIRON QUAL. 01/1998; 27(2).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This data set presents measured values of plant diameter and height, biomass of plant components, and nutrient (carbon, nitrogen, phosphorus, sulfur, potassium, calcium, magnesium, boron, copper, iron, manganese, and zinc) concentrations from a study of the effects of carbon dioxide and nitrogen fertilization on ponderosa pine (Pinus ponderosa Dougl. ex Laws.) conducted in open-top chambers in Placerville, California, from 1991 through 1996. This data set contains values from 1991 through 1993.
    01/1998;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The effects of elevated CO2 and N fertilization on fine root growth of Pinus ponderosa Dougl. ex P. Laws. C. Laws., grown in native soil in open-top field-exposure chambers at Placerville, CA, were monitored for a 2-year period using minirhizotrons. The experimental design was a replicated 3 × 3 factorial with a treatment missing; plants were exposed to ambient (≈ 365 μmol mol−1) air or ambient air plus either 175 or 350 μmol mol−1 CO2 and three levels of N addition (0, 100 and 200 kg ha−1 year−1). By the second year, elevated CO2 increased fine root occurrence and root length while N fertilization had no effect. The CO2 × N interactions were not significant. Neither elevated CO2 nor N fertilization altered fine root diameter. Fine root mortality was increased by increasing soil N but was reduced in elevated CO2. Highest fine root mortality occurred during summer and was lowest during winter. Elevated CO2 increased mycorrhizal and fungal occurrence earlier than N fertilization.
    Environmental and Experimental Botany 01/1997; · 3.00 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Interactive effects of atmospheric CO 2 enrichment and soil N fertility on above-and below-ground development and water relations of juvenile ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were examined. Open-top field chambers permitted creation of atmospheres with 700 L L 1 , 525 L L 1 , or ambient CO 2 concentrations. Seedlings were reared from seed in field soil with a total N concentration of approximately 900 g g 1 or in soil amended with sufficient (NH 4) 2 SO 4 to increase total N by 100 g g 1 or 200 g g 1 . The 525 L L 1 CO 2 treatment within the intermediate N treatment was excluded from the study. Following each of three consecutive growing seasons, whole seedlings of each combination of CO 2 and N treatment were harvested to permit assessment of shoot and root growth and ectomycorrhizal colonization. In the second and third growing seasons, drought cycles were imposed by withholding irrigation during which predawn and midday xylem water potential and soil water potential were measured. The first harvest revealed that shoot weight and coarse and fine root weights were increased by growth in elevated CO 2 . Shoot and root volume and weights were increased by CO 2 enrichment at the second harvest, but growth stimulation by the 525 L L 1 CO 2 concentration exceeded that in 700 L L 1 CO 2 during the first two growing seasons. At the third harvest, above-and below-ground growth increases were largely confined to the 700 L L 1 CO 2 treatment, an effect accentuated by high soil N but evident in all N treatments. Ectomycorrhizal formation was reduced by elevated CO 2 after one growing season, but thereafter was not significantly affected by CO 2 and was unaffected by soil N throughout the study. Results of the xylem water potential measurements were variable, as water potentials in seedlings grown in elevated CO 2 were intermittently higher on some measurement days but lower on others than that of seedlings grown in the ambient atmosphere. These results suggest that elevated CO 2 exerts stimulatory effects on shoot and root growth of juvenile ponderosa pine under field conditions which are somewhat dependent on N availability, but that temporal variation may periodically result in a greater response to a moderate rise in atmospheric CO 2 than to a doubling of the current ambient concentration.
    Plant and Soil 01/1997; 195(25):25-36. · 3.24 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Interactive effects of atmospheric CO_2 enrichment and soil N fertility on above- and below-ground development and water relations of juvenile ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were examined. Open-top field chambers permitted creation of atmospheres with 700 µL L^-1, 525 µL L^-1, or ambient CO_2 concentrations. Seedlings were reared from seed in field soil with a total N concentration of approximately 900 µg g^-1 or in soil amended with sufficient (NH_4)_2SO_4 to increase total N by 100 µg g^-1 or 200 µg g^-1. The 525 µL L^-1 CO_2 treatment within the intermediate N treatment was excluded from the study. Following each of three consecutive growing seasons, whole seedlings of each combination of CO_2 and N treatment were harvested to permit assessment of shoot and root growth and ectomycorrhizal colonization. In the second and third growing seasons, drought cycles were imposed by withholding irrigation during which predawn and midday xylem water potential and soil water potential were measured. The first harvest revealed that shoot weight and coarse and fine root weights were increased by growth in elevated CO_2. Shoot and root volume and weights were increased by CO_2 enrichment at the second harvest, but growth stimulation by the 525 µL L^-1 CO_2 concentration exceeded that in 700 µL L^-1 CO_2 during the first two growing seasons. At the third harvest, above- and below-ground growth increases were largely confined to the 700 µL L^-1CO_2 treatment, an effect accentuated by high soil N but evident in all N treatments. Ectomycorrhizal formation was reduced by elevated CO_2 after one growing season, but thereafter was not significantly affected by CO_2 and was unaffected by soil N throughout the study. Results of the xylem water potential measurements were variable, as water potentials in seedlings grown in elevated CO_2 were intermittently higher on some measurement days but lower on others than that of seedlings grown in the ambient atmosphere. These results suggest that elevated CO_2 exerts stimulatory effects on shoot and root growth of juvenile ponderosa pine under field conditions which are somewhat dependent on N availability, but that temporal variation may periodically result in a greater response to a moderate rise in atmospheric CO_2 than to a doubling of the current ambient concentration.
    Plant and Soil 01/1997; 195(1). · 3.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 CO_2. Based upon the literature, we hypothesized that 1) elevated CO_2 would cause increased growth and yield of biomass per unit uptake of N even if N is limiting, and 2) elevated CO_2 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 CO_2 caused growth dilution (decreased concentrations but not decreased uptake) of P, S, and Mg. Effects of elevated CO_2 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 CO_2, 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^+, Ca^{2+}, Mg^{2+} 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 CO_2 on mineralizeable N and extractable P, and positive effects of both N fertilization and CO_2 on exchangeable Al^{3+}. Soil exchangeable K^+, Ca^{2+}, and Mg^{2+} 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^+, Ca^{2+}, Mg^{2+} if N was nitrified and leached as NO^-_3.
    Plant and Soil 01/1997; 190(1). · 3.24 Impact Factor

Publication Stats

529 Citations
87.75 Total Impact Points

Institutions

  • 2000
    • Michigan State University
      East Lansing, Michigan, United States
  • 1995–2000
    • Desert Research Institute
      • Biological Sciences Center
      Reno, Nevada, United States
    • University of Nevada, Reno
      Reno, Nevada, United States
  • 1999
    • Texas Tech University
      • Department of Biological Sciences
      Lubbock, Texas, United States
  • 1996
    • University of Illinois, Urbana-Champaign
      • Department of Plant Biology
      Urbana, IL, United States
    • The Ohio Environmental Protection Agency
      Columbus, Ohio, United States