Environmental Needs for In-SeasonN Management

S.B. PhillipsVirginia Tech

Nutrient Inputs into the Chesapeake Bay

337.5284.8

183.2

050

100150200250300350400

1985 2000 2010

Mill

ion

lb N

/Yea

r

0

5

10

15

20

25

30

Million lb P

2 O5 /Year

19.12

12.8

27.13

19851985 20002000 GoalGoal

Virginia 13.46 9.61 6.00

Pennsylvania 4.44 3.48 2.26

Maryland 6.77 3.83 2.92

District of Columbia 0.16 0.14 0.34

New York 1.14 0.98 0.59

Delaware 0.60 0.53 0.30

West Virginia 0.57 0.55 0.37

TotalTotal 27.1327.13 19.1219.12 12.8012.80

Phosphorus Input into the Chesapeake Bay (millions of pounds/year)

Counties with 4-20 houses

Eastern Shore31,000 tons

Shenandoah Valley453,000 tons

South Central48,500 tons

Southeast7,400 tons

VA Poultry Industry: Total Manure Production ~ 560,000 tons/year.N = 34.7 Million lbs; Phosphate = 35.0 Million lbs

Phosphorus applied as poultry litter (4t/A) versus crop removal

0 50 100 150 200 250

CS/RS

Corn-SLG-17t

Rye-SLG-6t

Alfalfa-4t

Hay-3t

Pasture

Corn-GRN-130

PL

Added Removal

lbs P2O5/acre

Extractable nutrient (lb/acre)

Rel

ativ

e Yi

eld

(%)

0

20

40

60

80

100

"Critical Level"

Critical ValueFor P Loss??

P Lo

ss in

Sur

face

Run

off

Critical ValueFor Yield

VH

Phosphorus - Based Nutrient Management Plans

Delmarva Legislative Action

Nutrient Management LegislationMaryland: Water Qual. Imp. Act, 1998

NMP - 8 AUP-Based – Chemical Fertilizer 12/31/02P-Based – Manure/Biosolids 7/01/04

Delaware: Delaware Nutrient Mgmt. Law, 1999NMP - 8 AU or owns/leases/controls - 10 acP-Based – P appl. to high P soils cannot exceed 3-yr crop removal rate

Virginia: Poultry Waste Mgmt. Act, 1999NMP – 200 AUP-Based – 10/01/01P rates – not exceed crop needs or crop removal

Soil Test P - Eastern Shore of VA

VERY HIGH

HIGHMEDIUM

3.4 %29.1 %

67.5 %

Applying 31,000 Tons of Litter to Produce 150 bu/acre Corn:

N-Based - 7,4407,440 acres required P-Based - 37,00037,000 acres required

Poultry litter from 20000 broilers applied to 150 bu/acre corn crop

Nitrogen BasedNitrogen Based Rate = 4.2 t/A 150 lb PAN/A 260 lb P2O5/A 122 lb K2O/A

Land required = 36 A N needs met 240 lb P2O5/A SurplusSurplus 82 lb K2O/A SurplusSurplus

Phosphorus BasedPhosphorus Based Rate = 0.97 t/A 35 lb PAN/A 60 lb P2O5/A 28 lb K2O/A

Land required = 181 A 115 lb N/A DeficitDeficit P2O5 needs met 12 lb K2O/A DeficitDeficit

In-Season N Fertilization

Increased cost to growers Need to maximize efficiency

Improved Varieties Reduced Tillage Systems Accurate Rate Determination Optimize Application Timing Management of Spatial Variability

NOT A PUTTING GREEN!