Transcript Document

Great Lakes Protections Fund Grant 833 – Development of a
Phosphorus Soil Test Metric to Reduce Dissolved Reactive
Phosphorus Loading to Lake Erie.
Team Meeting # 5
July 23-24, 2013
Agenda Item 2. A review of basic concepts and terminology
related to phosphorus movement from cropland to streams
and rivers.
Some basic concepts and related terms
that will likely be used
Some
Agronomic
Terms
Particulate
Phosphorus
Losses
Soil System
Terms
Dissolved
Reactive
Phosphorus
Losses
See handout – Some basic concepts and terminology …
Some Agronomic Terms
No additional P fertilizer
recommended
Critical STP
for wheat
and alfalfa
Critical STP
for corn and
soybeans
What is the agronomic
range for soil test
values?
Tillage Terminology
CTIC Till Type Symbol to Use:
NT= No-Till,
MT = Mulch Till (>30%),
RT = Reduced Till (15-30%)
ST = Strip Till (>30%),
CT= Conventional Till (plow or
<15%)
Other terms
Mold board plowing (inversion
tillage)
Vertical tillage
Incorporation
Fall Tillage Symbols to use:
N = None,
FM = Mulch >30%,
FR = Reduced (Chisel/Disk<30%),
FS = Fall Strip Till,
FP = Fall Plow
Sandusky Watershed Stratified Soil Testing Program
Soil
Profile
Revised diagram for pathways of dissolved phosphorus runoff.
Dissolving and runoff of broadcast
fertilizer granules before incorporation.
M
a
c
r
o
p
o
r
e
s
Tile drainage
A comparison of maintenance phosphorus fertilizer application rates and watershed
export rates of total phosphorus and dissolved reactive phosphorus.
Sediment Delivery Ratio --- lbs/acre loss at watershed
divided by lbs/acre at edge of field
Enrichment Ratio --- mg P/kg SS at edge of field divided by
mg P/kg soil in the cropland soil.