USDA/ARS National Soil Tilth Laboratory 2004
Gulf Hypoxia Goals
Reduce average to 5000 km2 by 2015• 2001 Hypoxia Action Plan - 30% N
reduction target• Updated Gulf Science – 35-45%, up to
55% & 60% N reduction, P reduction• SAB report 8/27/07 – at least 45%
reductions of both N and P
2001-2005 Nitrogen Loadings to the Gulf
32% N reduction – “previous” regression method for USGS monitoring data
21% N loading reduction – “new” regression method for USGS monitoring data
No corresponding change in size of zone
Role of fertility management to reduce N transport to water resources and to meet Gulf hypoxia N reduction targets?
Impact of annually increasing corn yields with steady fertilizer rates?
Excess nutrients?
Iowa’s Statewide Nutrient BudgetNitrogen Balance
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
4,500,000
N Inputs N Outputs
Tons
Iowa Statewide Hypoxia Strategy Dean’s 10/15/07 Strawman
N Reduction Target 45%, at least
Improved fertility mgmt 10%Riparian buffers <1%Drainage management ??Not discovered practices ??Row crop land retirement ??N sink wetlands 30+%
Needed “Scaling” of N Sink WetlandDeployment
• Current Iowa CREP – 20 sites/year
• Adoption level to achieve 40-50% reduction of statewide NO3 transport to water resources for Gulf hypoxia goal
3,000 – 10,000 N sink wetland sites in Iowa
10,000 sites478 sites
1999 2000 2001 2002 2003 2004 2005 2006 2007
CREP Sign
ing Cere
mony at
Iowa S
tate Fair
CREP discuss
ion initia
ted with
FSA
2000 Io
wa legisla
ture
pass
water in
itiativ
e –
includes C
REP
SFY2001 $3,000,00
0 appropria
tion
SFY2001 ($
2,990,583)
de-ap
propria
tion
SFY2002
$3,000
,000 a
ppropria
tion
SFY2002 ($
2,965,465)
de-ap
propria
tion
Region
al Perm
it #34 i
ssued
First s
ites a
pprove
d
through R
egiona
l
Permit #
34CREP Engin
eering o
utsou
rced
NRCS desig
ns firs
t 6 si
tes under N
WP 27
Individ
ual 404
permits
requir
ed & in
itiate
progra
mmatic ag
reemen
ts for
RP
20 C
REP wetla
nd proj
ects
cons
tructe
d to date
– 6
unde
r NWP 27
, 14 un
der
indivi
dual
404 perm
its
Dedica
ted C
REP Field/
Lando
wner Conta
ct Supp
ort
1993 – 2007 IDALS Funding of N
-sink
wetland re
search
, ISU
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
CR
EP
P
rogr
ess
Deappropriation
RegulatoryE
conomics
?