PURPOSE
To determine mycorrhizal fungus species composition and number in the Konza Prairie LTER Belowground study plots. Percentage mycorrhizal colonization and colonization intensity of sampled plant roots will also be determined.
LOCATION OF SAMPLING STATIONS
LTER belowground study plots - sampled every 5 years.
VARIABLES MEASURED
1) Mycorrhizal species composition per gram (dry wt) soil.
2) Spore density of each mycorrhizal species per gram (dry wt) soil.
3) Percent mycorrhizal root colonization and colonization intensity of sampled plant roots.
METHODS
Ten 15 x 1.8 cm cores are removed from each LTER sample plot. The cores are randomly taken from throughout the plots with a 25 x 1.8 cm soil probe. Percent moisture is calculated and 100-500 g (dry wt) soil are examined from each sampling site. Samples are blended in water, wet sieved through a 38 æm sieve, decanted and subjected to 20, 40 and 60% sucrose density centrifugation (Daniels and Skipper, 1982) to separate spores from organic matter. Spores thus collected are then examined microscopically to determine the number of spores and identity of each species present. Roots from each sample were washed free of soil, stained with trypan blue (Phillips and Hayman, 1970), and examined microscopically to determine percentage root colonization and colonization intensity (Kormanik and McGraw, 1980).
Daniels, B. A., and H. D. Skipper (1982). Methods for the recovery and quantitative estimation of propogules from soil. IN: Methods and Principles of Mycorrhizal Research (N. C. Schenck, Ed.), pp. 29-37. American Phytopathological Society, St. Paul, Minn.
Kormanik, P. P., and A. C. McGraw (1982). Quantification of vesicular-arbuscular mycorrhizae in plant roots. IN: Methods and Principles of Mycorrhizal Research (N. C. Schenck, Ed.), pp. 37-47. The American Phytopathological Society, St. Paul, Minn.
Phillips, J. M. and D. S. Hayman (1970). Improved procedures for cleaning roots and staining parasitic and vesicular-arbuscular mycorrhizal fungi for rapid assessment of infection. Transactions of the Mycological Society 55:158-160.
To measure the effects of burning, mowing, and N and P fertilization on pH; available P; exchangeable, soluble and total- N; cation exchange capacity; exchangeable Ca, Mg, and K; extractable Fe, Mn, Zn, and Cu; and total-P.
LOCATION OF SAMPLING STATIONS
Grid B-16 behind the stone house. The soil on the sites is an Irwin silty clay loam with approximately 15% slope. Sixty-four, 12 X 12 meter plots are arranged in a split-split design to measure burning, mowing, and fertilization effects.
FREQUENCY OF SAMPLING
Twice per year, early spring and fall, every two years.
VARIABLES MEASURED
Unless otherwise noted, the methods used in measuring the variables listed below follow the procedures in "Recommended Chemical Test Procedures for the North Central Region", Bulletin 499, North Dakota Agricultural Experiment Station, North Dakota State University, Fargo North Dakota (1980) found in APPENDIX D.
1) Nitrate and Exchangeable NR+ 4. A 10:1 mixture of 2 M KCl and soil are shaken for one hour and filtered. Nitrate and ammonium are measured using Technicon Autoanalyzer.
2) Available P (Bray).
3) Total-N (Kjeldahl).
4) pH. (1:1 water)
5) Organic matter
6) Exchangeable K, Ca, Mg; Cation Exchange Capacity. Five grams of soil are suspended in 50 mL of 1 M NH4OAc for 25 minutes, centrifuged, and filtered. This process is repeated three times. The suspension is washed with ethanol, centrifuged, and finally extracted with 2 M KCl. Exchangeable K, Ca, and Mg are determined in the original ammonium acetate washings, and CEC determined by measuring the residual NH4+ in the KCl extract.
7) DTPA-Extractable Cu, Zn, Mn, and Fe.
METHODS
To avoid destructive over-sampling, all scientists on the Belowground Plots use the same samples. A composite of several 5 cm cores are taken from each plot, and sub-samples distributed to each investigator. A 50 g sub-sample is generally plenty for soil chemical analysis. Samples are air dried, ground to pass a 2 mm sieve, and stored in plastic containers for future analyses.
PURPOSE
Monitor long-term changes in plant production and nutrient balance due to the effect of annual burning, mowing, and nitrogen and phosphorus fertilization.
LOCATION OF SAMPLING STATION
HQC
FREQUENCY OF SAMPLING
Once per year for peak biomass in August or September. For the mowed plots an additional sample is taken at mid-season (June) before mowing. Beginning in 1992, two transects were clipped per plot in the fall.
VARIABLES MEASURED
1) Plant biomass sorted by live, dead, forbs and woody, and litter
2) Total-N and total-P
METHODS
One 0.1 m2 quadrat is clipped from each plot. The plant material is dried at 60oC and then separated into live, dead, forbs, and woods, and litter material. The dried material is then ground to pass a 2 mm screen and acid digested by the Kjedahl procedure and the solution analyzed for total-N and total-P by automated calorimetric analysis.
PURPOSE
Monitor long-term changes in plant root production and nutrient balance due to the effect of annual burning, mowing, and nitrogen and phosphorus fertilization.
LOCATION OF SAMPLING STATION
HQC
FREQUENCY OF SAMPLING
Once every five years in August or September.
VARIABLES MEASURED
1) Root biomass sorted by live, dead, and forbs
2) Total-N and total-P
METHODS
Two 5 cm diameter by 20 cm deep soil cores are sampled from each plot and combined. The roots are then washed, separated, and dried at 60oC. The dried material is then ground to pass a 2 mm screen and acid digested by the Kjedahl procedure. The solution is then analyzed for total-N and total-P by automated calorimetric analysis
.
PURPOSE
To monitor nematode densities and trophic composition at the Konza Prairie LTER belowground study plots.
LOCATION OF SAMPLING STATIONS
The belowground study plots are located south of the aboveground burn treatment plots, (grids B-16 and C-16).
SAMPLING FREQUENCY
Soil cores are collected in the fall of every other year,
beginning in May, 1987. Sampling will be reduced to once per five
years after the first few years of the study.
2) Trophic composition
METHODS
All plots will be sampled with a 5 cm diameter coring tool to
a depth of 20 cm. The Christie-Perry Technique, as modified by Dr.
C. C. Russell at Oklahoma State University, will be used to extract
the nematodes from a composite sample obtained from four soil cores
for each treatment. The following is a brief summary of the steps
in the extraction procedure:
1) A 100 cm3 soil sample is suspended in 3 L of H2O and
allowed to settle for 90 seconds.
2) The soil/H2O solution is poured through a 15 mesh sieve
nested over a 400 mesh sieve.
3) The screenings from the 400 mesh screen are washed onto
two layers of Scotties brand tissue which have been supported
in a 4 inch diameter pot by a wire screen. The H2O level
in the pot should just cover the sample.
4) After 24 hours, nematodes that have migrated through the
tissue are collected from the bottom of the pot by
decanting the H2O to a volume of 40-50 ml.