Table 1. Summary of soil quality analysis sampling procedures, schedules, and methods
Soil Quality
Soil Sampling
Parameter
Procedure
Sampling Schedule
Analysis Method
Soil temperature One iButton/plot
Continuous throughout fall
iButton datalogger
and growing season
Soil moisture
One probe/plot
"
Soil moisture sensor
PHYSICAL
Aggregate
Composite of 5 soil Before seaweed application Wet sieving for
stability
cores (depth=15
(Oct 11); before sweet corn determination of water stable
cm) per plot
seeding (May 12); at sweet
aggregates
corn harvest (Sept 12)
Available water
Two 15 cm cores
"
Water content at field
capacity
per plot
capacity
Infiltration
One ring/plot
"
Flooded/ponded
infiltrometer method
Bulk density
Three samples/plot "
Dry weight per unit volume
BIOLOGICAL
Organic matter
Composite of 5 soil Before and after seaweed
Loss-on-ignition at 550°C
content
cores (depth=15
application, monthly
cm) per plot
through growing season
Active carbon
"
"
KMnO4 oxidation,
colorimetric determination
Potentially
"
"
Comparison of extractable
mineralizable
NH4 before and after 7 d
nitrogen
incubation
Beneficial and
"
"
Modified pie plate extraction;
plant-parasitic
counting; dT-RFLP community
nematodes
analysis
Soil respiration
In-field test (1/plot) "
CO2 evolution measurement
Fungal:bacterial Composite of 5 soil "
Fungal ergosterol extraction;
biomass ratio
cores (depth=15
comparison to total microbial
cm) per plot
biomass N
Microbial
"
"
Chloroform fumigation,
biomass N
K2SO4 extraction
Earthworm
30 x 30 x 30 (width Before seaweed application Counting
abundance
x length x depth)
(Oct 11); before sweet corn
sample (1/plot)
seeding (May 12); at sweet
corn harvest (Sept 12)
Insect
Three pitfall
Before and after seaweed
Pitfall trap collection, visual
abundance
traps/plot
application, monthly
identification to family
through growing season
CHEMICAL
Nitrate,
ammonium
Composite of 5 soil
cores (depth=15
cm) per plot
"
"
KCl extraction, microplate
colorimetric analysis
"
Potassium
Ca, Mg, Fe, Al,
Mn, Zn, Cu
Sulfur, sulfate
"
"
"
"
Morgan's Solution extraction,
microplate colorimetric
analysis
KCl extraction, ICP analysis
X-Ray Florescence
"
"
Heavy metals
(Pb, Cd, Ni, Cr)
"
Salinity
(electrical
conductivity)
pH
"
Before seaweed application
(Oct 11); before sweet corn
seeding (May 12); at sweet
corn harvest (Sept 12)
Before and after seaweed
application, monthly
through growing season
"
Phosphate
"
XRF, aqeuous extract and
spectrophotometric analysis
XRF
EC meter, 1:2 soil:water
pH meter, 1:1 soil:water