Photosynthetic recovery in arctic caribou forage lichens following a long-term field sulfur dioxide fumigation

The gross photosynthetic response of Cladonia stellaris (Opiz.) Pouz. & Vezda., Cladonia rangiferina (L.) Wigg., and Cetraria cucullata (Bell.) Ach. was monitored during three growing seasons subsequent to a long-term, in situ SO2 fumigation conducted in 1978 at Anaktuvuk Pass, AK. The lichen vegetation which had experienced the greatest SO2 stress during the 1978 fumigation remained photosynthetically inactive. Significant photosynthetic recovery was discovered in the test species which had experienced sublethal concentrations of SO2; however, their photosynthetic capacities remained less than controls.

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Effects of a long-term field sulfur dioxide fumigation on Arctic caribou forage lichens

Canadian Journal of Botany ◽

10.1139/b80-258 ◽

1980 ◽

Vol 58 (21) ◽

pp. 2235-2240 ◽

Cited By ~ 22

Author(s):

Thomas J. Moser ◽

Thomas H. Nash III ◽

W. Dennis Clark

Keyword(s):

Sulfur Dioxide ◽

Stress Gradient ◽

Growing Season ◽

Photosynthetic Response ◽

Test Species ◽

Chlorophyll Contents ◽

Cladonia Rangiferina ◽

Term Field

The gross photosynthetic response of Cladonia stellaris (Opiz.) Pouz. & Vezda., Cladonia rangiferina (L.) Wigg., and Cetraria cucullata (Bell.) Ach. to a continuous, long-term, in situ SO2 fumigation was monitored during the growing season at Anaktuvuk Pass, Alaska. The photo-synthetic capabilities of the test species were either destroyed or significantly reduced depending upon the SO2 stress gradient over the fumigation plot. Additional sampling of the plot 1 year after termination of the fumigation revealed no significant recovery in photosynthesis, and chlorophyll contents of the test species were significantly less than the controls.

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Diurnal gross photosynthetic patterns and potential seasonal CO2 assimilation in Cladonia stellaris and Cladonia rangiferina

Canadian Journal of Botany ◽

10.1139/b83-073 ◽

1983 ◽

Vol 61 (3) ◽

pp. 642-655 ◽

Cited By ~ 14

Author(s):

Thomas J. Moser ◽

Thomas H. Nash III ◽

Steven O. Link

Keyword(s):

Photosynthetic Activity ◽

Growing Season ◽

Early Morning ◽

Co2 Assimilation ◽

Atmospheric Moisture ◽

Growing Seasons ◽

Late Evening ◽

Summer Rain ◽

Cladonia Rangiferina

The daily, in situ gross photosynthetic patterns of Cladonia stellaris (Opiz.) Pouz. & Vězda. and Cladonia rangiferina (L.) Wigg. were monitored during portions of the 1977, 1978, and 1979 growing seasons at Anaktuvuk Pass, Alaska. Photosynthetic activity in both species closely paralleled atmospheric moisture status, where peak photosynthetic rates were attained during or following sporadic summer rain. In addition, thallus absorption of moisture during extended periods of high atmospheric water vapor content gave rise to short periods of minimal photosynthetic activity. During late evening and early morning hours moistened thalli exhibited minimal or no photosynthetic activity, coinciding with consistent attenuation in solar radiation during these periods. Photosynthetic activity was not homogeneous throughout the thallus. The greatest activity occurred in the apical regions and decreased progressively into the basal regions. The apical 10-mm regions of C. stellaris and C. rangiferina thalli accounted for approximately 50% of their photosynthetic capabilities. The potential gross CO2 assimilation of the apical 10-mm regions over 72 days of the 1978 growing season was estimated at approximately 35 g CO2∙m−2 and 16 g CO2∙m−2 for C. stellaris and C. rangiferina, respectively.

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Irrigation of maize (Zea mays L.) in relation to fertilization in a long-term field experiment

Acta Agronomica Hungarica ◽

10.1556/aagr.53.2005.1.5 ◽

2005 ◽

Vol 53 (1) ◽

pp. 41-46 ◽

Cited By ~ 7

Author(s):

A. Megyes ◽

J. Nagy ◽

T. Rátonyi ◽

L. Huzsvai

Keyword(s):

Field Experiment ◽

Crop Production ◽

Strongly Correlated ◽

Growing Seasons ◽

Production Factors ◽

Maize Yields ◽

Set Up ◽

Fertilizer Rates ◽

Term Field

The objectives of this study were to examine the correlation between factors of great significance for crop production, especially between irrigation and fertilization, and to evaluate the effects of irrigation and fertilization on maize yields over four growing seasons (2001-2004) in a long-term field experiment set up at the Látókép Experimental Station of the Centre for Agricultural Sciences of Debrecen University. The results showed that irrigation and fertilization were strongly correlated with the yield. The effect of irrigation depended on the natural water and nutrient supplies of the soil, and on the specific fertilizer rates. The results indicated that both fertilization and irrigation had a significant effect on the yield. The correlation between the year and the crop production factors was also significant. The yield-increasing effect of irrigation and fertilization differed significantly in the experimental years.

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Fate of 15N-labelled fertilizer in a long-term field trial at Ropsley, UK

The Journal of Agricultural Science ◽

10.1017/s0021859697004425 ◽

1997 ◽

Vol 129 (1) ◽

pp. 49-63 ◽

Cited By ~ 4

Author(s):

A. BHOGAL ◽

S. D. YOUNG ◽

R. SYLVESTER-BRADLEY

Keyword(s):

Field Trial ◽

N Uptake ◽

Significant Loss ◽

Growing Seasons ◽

Large N ◽

Long Term Effect ◽

Added Nitrogen Interaction ◽

Labile N ◽

Term Field

In 1992 and 1993, eight rates of 15N-labelled fertilizer (0–245 kg ha−1) were applied to winter wheat growing on the Ropsley long term field trial where eight different N amounts had been applied annually since 1978. The fate of the labelled N in the crop and topsoil (0–23 cm) was determined at harvest in the year of 15N application and in the first and second residual years.By harvest in the second residual year, 60–77% of the original labelled application had been recovered in the crop and topsoil with 23–40% lost. These losses virtually all occurred within the first two growing seasons; there was no significant loss during the second residual year. Significant changes in the 15N balance were observed at N applications in excess of the range 140–175 kg ha−1 which suggested a marked decrease in the efficiency of N use and an increase in residual labile N in the soil at harvest. At low N applications (<175 kg ha−1), a positive added nitrogen interaction (ANI) was observed: 40–50% of this was a residual ANI due to the short or long term effect of applying N fertilizer, and the remainder was probably an apparent ANI due to pool substitution in the immobilization process. At large N applications (>175 kg ha−1) a negative ANI was observed: large N applications resulted in a net suppression of soil N uptake due to substitution by fertilizer for a limited plant N demand.

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