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Natalie Rossington

on 29 November 2012

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Transcript of Ferris

Decomposition Cycle! Deposition of organic matter (OM) and plant detritus Decomposed by microorganisms bacteria
arthropods collembola
and many more Release of nutrients to soil
food web Release of carbon dioxide to soil and atmosphere Root and bacteria uptake
and immobilization
of nutrients Temperature
pH Regulative Factors Nutrients
Electron acceptors
OM Quality Decomposition Rate k= litter mass (mg) time (days) Organic Matter Quality Cellulose Lignin Wheat Straw Composition Celluose = 40.4%
Hemicellulose = 30.1%
Lignin = 4.6% Methods and Materials ) ( ln High Low C:N Ratio (Stipa pulchra): 68.2 NORTH SOUTH Wild Oats Fox tail Purple Needle Grass Purple Needle Grass Wild Oats Fox tail Poison Oak Coffeeberry Coast Live Oak Coyote Bush Cal Poly Morphological Differences NORTH SOUTH 0-5cm Texture: SCL
Color: 10YR 3/3 0-5cm Texture: CL
Color: 10YR 3/3 pH: 6.05
Rock Frags:
Gravelly pH: 5.51
Rock Frags: None A A A2 5-30cm Texture: CL
Color: 10YR 3/4 Bt 30-35cm Texture: CL
Color: 7.5YR 3/3 pH: 6.25
Rock Frags: None Bt1 5-25cm Texture: C
Color: 7.5YR 3/3 pH: 6.72
Rock Frags:
Gravelly Bt2 25-40cm Cr 40cm+ Texture: C
Color: 7.5YR 3/3 pH: 6.82
Rock Frags: None pH: 6.07
Rock Frags: None Litter Bags rates can be used to monitor the whole soil system Calculating Decomposition Rates of a Native Grass using Mesh Litter Bags Hypotheses and Objective Hypotheses 1. The decomposition rate will be higher in the north aspect soil pit. 2. The decomposition rate will be highest in the bags in the 5cm horizon. Objective 1. Compare decomposition rates on north and south aspects and at four different depths. Litter Bag Study enclose a known mass of OM in wire mesh bag
wire mesh allows organisms to enter and exit freely - mesh >2mm allows microfauna,
mesofauna and some macrofauna
to enter Litter Bag Challenges travel bags
choosing appropriate variables
soil addition to bags
errors in data
replicates Installation and Removal travel bags were taken to the soil pit
three litter bag replicates (A, B, and C) were installed at four depths, 0cm, 5cm, 15cm, and 30cm, at the North and South pits
litter bags were installed in the open soil face using "cubbyholes"
the open soil pits were back filled in order to ensure proper horizonation Installation Removal litter bags were carefully removed from the surface and from inside the soil pit Calculation of Rate (k) grass was emptied from bag, separated from soil and weighed (including travel bags)
each litter bag weight was calibrated to the travel bag weight loss k= ln ( initial (mg)-final (mg) ) ( - travel bag (mg) time (days) 11cm 12cm about 4g of Stipa pulchra
per bag each bag included a metal
label tag staple numbers were
limited 30 Litter Bags 4 depths with 3
replicates each at both
sites 3 travel bags for each
site .85mm .85mm ) Results and Discussion Aspect Our Hypothesis The decomposition rate will be higher in the
north aspect soil pit. Depth Our Hypothesis The decomposition rate will be highest in the bags in the 5cm horizon. Conclusions Results and Discussion Results and Discussion Scott Pensky Natalie Rossington Ariel Namm Decomposition rates on north vs.
south aspects at increasing depth south aspect has a generally higher
decomposition rate
more microbial activity at the south aspect
than expected
temperature may be the more limiting factor
than moisture content during the time frame
higher pH in south aspect both aspects follow a similar depth trend
- increased decomposition rate at 5cm depth
- decrease in rate from 5 to 15cm
- surprising increase in rate from 15 to 30cm
(opportunistic microbes and burrows?) trend is correlated to Solvita trend high decomposition rates show high microbial activity and can be used to monitor the health of a soil system
litter bag studies are simple and accessible method to measure decomposition rates Our Experiment temperature seemed to be an influential factor in litter decomposition rates
a high decomposition rate located in the 5cm horizon
similar trend as Solvita microbial respiration tests
future experiments should have more replicates, longer time frame, look at microarthropod influence, less variables Other Litter Bag Studies litter bag ANOVA analysis useful for comparison between treatments, not to model decomposition rate in soil (Wieder and Lang, 1982)
a study by Sariyildiz and Anderson (2003) showed microclimate had an influence on decomposition rates
a similar study found higher decomposition rates on north compared to south aspect slopes over two years (Sariyildiz et al., 2005)
- in this study, soil pH was highest at the north site References (Kuers and Simmons, 2005) Decomposition rates at increasing depth on north vs. south aspect CO2 respiration with increasing depth Kuers, K., and J. Simmons. 2005. Litter Decomposition. CAWS. Sewanee: The University of the South. Sariyildiz, T., and J.M. Anderson. 2003. Decomposition of sun and shade leaves from three deciduous tree species, as affected by their chemical composition. Bio Fert Soils 37:137-146. Sariyildiz T., J.M. Anderson, and M. Kucuk. 2005. Effects of tree species and topography on soil chemistry, litter quality, and decomposition in Northeast Turkey. Weider, R.K., and G.E. Lang. 1982. A critique of the analytical methods used in examining decomposition data obtained from litter bags. Ecology 63:1636-1642. (Carrillo et al., 2011)
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