Managing P & N Nutrient Resources Agronomy In-service January 3, 2013 Greg LaBarge, Field Specialist, Agronomic Systems

Managing P & N Nutrient Resources

Agronomy In-serviceJanuary 3, 2013

Greg LaBarge, Field Specialist, Agronomic Systems

Discussion

• Why be concerned with nutrient/sediment

• Phosphorus – What do we want farmers to do– Tri-state Philosophy and Status

• Nitrogen– Economic rate calculator

• Other Issues

Why be concerned about nutrients/sedimentation leaving edge of field?

• Water Quality Concerns in water bodies– EPA water quality measured as “intended use”– Regulation

• Ohio Ag Pollution Abatement

from “manure and sediment

bound nutrients” to “nutrients”

– Sedimentation removal• Cost Maumee and Harbor

($5,000,000 annual)

• Good Stewards

and Public Pressure• Economic Cost (Loss) of Nutrients

Value of Nutrient In Maumee River

• Average value of nutrient lost WY2008-2011 – based on $650 per ton P2O5 & $0.65 cent

Nitrogen

Nutrient Value

Phosphorous $ 4,129,291

Nitrogen (Nitrate) $39,694,230

Total $43,823,521

Per acre $13.52

Phosphorus

• Soil reactions of phosphorous • Nutrient Movement • What do we want farmers to do• Do the tri-state recommendations still work• Recommendation resources

Three Important Soil P Fraction for Plant Nutrition

Soil Solution Labile P Nonlabile P

Nutrient Movement

Solution PSolution P

HH22POPO44--

HPOHPO442-2-

<0.3 ppm<0.3 ppm

Solution PSolution P

HH22POPO44--

HPOHPO442-2-

<0.3 ppm<0.3 ppm

AdsorbedP

Labile P

Secondary MineralsFe/AlPO4

CaHPO4

Nonlabile P

Primary Minerals

Nonlabile P

OrganicMatterBound

PNonlabile P

Fertilizer Manure

Adsorption

Desorption

Dissolution

Precipitation

Dissolution

Mineralization

Immobilization

Plant uptake

Leaching

Total P in soil – 50-1500 ppm ~ 100-3000 lb/acre

Labile P

Leaching

Water Definitions

• Total Phosphorus"Total" phosphorus is largely defined on the basis of how much phosphorus in its various forms will be oxidized into orthophosphate by a

specific oxidant.

• Water soluble P–Dissolved reactive phosphorus (DRP)–Bioavailable Phosphorus The soluble form of the nutrient phosphorus, which is readily available for use by plants. consist largely of the inorganic orthophosphate (PO4) form of phosphorus.

• Particulate P Soil attached P

Source: Heidelberg University

Maumee River Gauging Station

Source: Hiedelberg University

Increased DRP?

• Increased broadcast applications– Time required for nutrient to attach to sites– Stratification and preferential flow

• No-till• Time needed to re-establish preferential flow after tillage

• Soil tests levels– STL are in decline & P fertilizer sales are declining

• Tile increased intensity• Rotation changes• Size of farm

Nutrient Movement• Can they move?

– Yes. Largest deciding factors are soil texture and nutrient concentration (tillage is a factor as well, obviously)

Boem et al., SSSAJ, 2008

Nutrient Movement

• Nutrient concentration causing nutrient leaching

Mehlich-3 soil P, mg/kg

Dissolved P,mg/L

0.5

0

1.5

1

0 200 400 800600

Drainage from 50-cm undisturbed soil lysimeters

Discussions agricultural reductions

• Five month public process

• 100 plus individuals involved

• Final report• http://

www.dnr.state.oh.us/portals/12/docs/waterqualityreport.pdf

What contribution to reduction can agriculture make?

• 4R Nutrient Stewardship– ‘Right’ Rate, ‘Right’ Timing, ‘Right’ Placement & ‘Right’

Source

• Industry Developed Program – Global– http://www.nutrientstewardship.com/

• Goals– Increase crop production & improve profitability– Minimize nutrient loss & maintain soil fertility– Ensure sustainable agriculture for generations to come

http://www.nutrientstewardship.com/

Additional In-service

For More Information: https://www.agronomy.org/

https://www.agronomy.org/

Recommendations to Reduce Nutrient

Movement off -site

• The ‘Right’ Rate.– Good representative soil sample should be the basis

for fertilizer application.– Utilize Ohio State University Extension Agronomic

Recommendations for nutrient application.– Records should be kept for all soil tests,

recommendations and applications as well as crop and resulting yields.

– http://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins Source: Ohio Director’s Working Group on Ag Nutrients 4/12

http://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins



Fertility Rates

Critical Level

• “…the soil test level above which the soil can supply adequate quantities of a nutrient to support optimum economic growth.”

• Below the CL”…the soil is not able to provide P and K requirements of the crop.”

• Above the CL”…the soil is capable of supplying the nutrient required by the crop and no response to fertilizer would be expected.”

Critical Level

Crop P- Bray 1(PPM)

P- Bray 1 (lbs/A)

Corn & Soybeans 15 30

Wheat & Alfalfa 25 50

2104/19/23

Spatial Variation

0-15 15-30 30-45 45-60 60-75 75-90 90-105 105-120 120-135

Soil test P

22 04/19/23

Nutrient Distribution• Mean soil test P – 18 ppm• Median soil test P – 16 ppm

Maintenance Plateau Range

• “Designed to replace nutrient lost each year through crop removal.”

• “…no response to fertilizer in the year of application expected.”

• “No response to placement technique such as banding or stripping or the use of P and K starter fertilizer…”

Corn

Maintenance Limit

Crop P- Bray 1(PPM)

P- Bray 1 (lbs/A)



Drawdown

• “When soil test levels exceed maintenance plateau level (Maintenance Limit), the objective of the fertilizer recommendation is to utilize residual soil nutrients….There is no agronomic reason to apply fertilizer when soil test are above the maintenance plateau level.”

Drawdown

Crop P- Bray 1(PPM)

P- Bray 1 (lbs/A)



Corn

"What do you mean do not put any P on, won't my soil test drop?"

Two part answer. First yes, soil test levels will drop, but if you are above the crop response range for the crop it really is not a problem crop production wise. If you are above 30 PPM there is no yield benefit and if you are way above this level there is an economic benefit to using this soil stored P.

"What do you mean do not put any P on, won't my soil test drop?“ Part 2

The second part of the answer is soil test do not drop 1 to 1 with crop removal. A 150 bushel corn crop removes (150 bushel * 0.37 Crop removal = 56 lbs). Phosphorous chemistry in the soil buffers the crop removal so that for each 15-20 lbs of P2O5 removal phosphorous levels in the soil are lowered 1 PPM. So our 150 bushel crop will lower the soil test at around 3-4 PPM.

Expected Soil Test Changes

• The buildup equations in the Tri-states

• 20 lbs./A of P2O5 to change soil test P levels one ppm.

• 6 to 10 lbs./A of K2O are required to change soil test 1 ppm depending upon the soil CEC.

Equations

BUILDUP EQUATION for P: lb P2O5/A to apply = [(CL - STL) x 5] (YP x CR) MAINTENANCE EQUATION for P: lb P2O5/A to apply = YP x CR DRAWDOWN EQUATION for P: lb P2O5/A to apply = (YP x CR) - [(YP x CR) x (STL - CL 15))/10]

CL = critical soil test level (ppm) STL = existing soil test level (ppm) YP = crop yield potential (bu per acre for grains, tons per acre for forages) CR = nutrient removed per unit yield (lb/unit) CEC = soil cation exchange capacity (meq/100g)

Recommendation Resources

Recent looks at Tri-state Critical Values

• 1993-1999. Dr. Jay Johnson study at Western Branch relative yield without fertilizer

• 2006-present. Dr. Robert Mullen study at Western, Northwest and Wooster fertilizer at 0, 1X, 2X rate based on tri-state

Critical Levels• Ohio State data – relative corn yield and STP

50

60

70

80

90

100

110

0 20 40 60 80

Soil test P, lb/acre

Rel

ativ

e yi

eld

, %

of

max

Critical Value – 30 lb/ac

Critical Levels

• Ohio State data – relative soybean yield and STP

0

20

40

60

80

100

120

140

0 20 40 60 80

Soil test P, lb/acre

Rel

ativ

e yi

eld

, %

of

max

Critical Value – 30 lb/ac

Iowa

Are Current Critical Levels Still Valid?

• Northwest Research Station near Custar, Ohio

• Initial soil test levels– P – 39 ppm; K – 272 ppm; CEC – 24 meq/100 g– Critical levels – 15 ppm (P) and 135 ppm (K)

• Would you expect much response at this location?


• Phosphorus response in corn-soybean rotation


• Phosphorus response in corn-corn-soybean rotation


• Western Research Station near Springfield, Ohio








• East Badger Farm near Wooster, OH







Other Rate Considerations

• Product Margin vs Service

• Consider all nutrient sources


• Precision Application– Sampling scheme– Variable rate across

field• Goal• Even levels across

field-good for pH• Application rate

based on crop response


• Rented vs Owned– Fertility Levels– Structures


Movement off -site

• The ‘Right’ Time.– Nutrients should not be applied to frozen or

snow covered ground.– Nutrients should be applied as close to crop

utilization as possible.– Or if not applied close to utilization practices

should be used to keep it in forms that limit movement offsite

Source: Ohio Director’s Working Group on Ag Nutrients 4/12


Movement off -site

• The ‘Right’ Place.– Phosphorous applications should be injected

or incorporated whenever possible.– If surface applications are made, it should

have a growing crop or cover as soon as possible.


0

2

4

6

8

10

12

14

16

Tilled-incorporated Tilled-surface No-till cover No-till

Dis

solv

ed P,

ppm

Control

DAP

Poultry litter

Mullen, 2011, unpublished

Rainfall simulator study, NW Ohio, Nov 2009

• P sources applied at 80 lb P2O5 per acre• Total P loss < 2% of amount applied• Rain @ 2.4”/hour; first 30 minutes runoff

Placement

• Row Starter

• Foliar

• Strip Tillage

• Other banded application

• Incorporation


Movement off -site

• In addition to the 4 R’s- Improve Soil Quality.– Soil organic matter.– Soil compaction.– Water infiltration rates.– Methods to reduce runoff.


Source: http://leopold.iastate.edu

Tiling

Blind Inlets

Contribution


Movement off-site • In addition to the 4 R’s- Improve Water Management and

Possible Treatment of Drainage Water.– Repair broken subsurface drainage.– Treating surface inlets runoff into subsurface drainage

systems.– Treating concentrated surface runoff areas.– Controlled drainage.– Constructed wetlands for treatment– Improved designed filtered areas, biofilters– Alternative drainage ditch designs


Nitrogen Recommendations

Nitrogen RecommendationsNitrogen Recommendations

Relationship between yield level and agronomic optimum N rate in Ohio (90 sites – corn after soybeans)

626204/19/2304/19/23


So…Land Grant Universities (in the Midwest) have moved away from yield goal based recommendations as a result of this informationWhat are we left with?

It’s a risk model, what is the risk of a certain N rate with regard to agronomic performance while considering the economic factors

636304/19/2304/19/23

Where we are today with new recommendations

Where I think we should go?Using the above template, evaluate different sources, timings, and methods of N application to define risk of yield loss at various N rates

Lots of data yet to be collected


646404/19/2304/19/23

Economic Nitrogen Rate Calculators

• Mullen Developed http://agcrops.osu.edu/specialists/fertility/fertility-fact-sheets-and-bulletins Will be updated by 3/1/2013

• Iowa State (houses midwest verson) http://extension.agron.iastate.edu/soilfertility/nrate.aspx



http://extension.agron.iastate.edu/soilfertility/nrate.aspx

http://extension.agron.iastate.edu/soilfertility/nrate.aspx

Iowa Site

Other Issues

• NRCS 590 Nutrient Management and 633 Manure Nutrients was combined into one 590 standard

• NRCS CAPS (Conservation Activity Plan)– 102 Comprehensive Nutrient Management Plan– 104 Nutrient Management Plan– Systems Soil testing, precision application, cover

crops, controlled traffic, strip tillagehttp://www.nrcs.usda.gov/wps/portal/nrcs/main/national/programs/technical/tsp/

http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/programs/technical/tsp/

http://www.nrcs.usda.gov/wps/portal/nrcs/main/national/programs/technical/tsp/

Summary

• Building case for better nutrient management-economic and environmental

• Tri-state Philosophy– Tri-state P & K Recommendations are sound

• What do we want farmers to do:– 4R Nutrient Stewardship

• Introduction to Nitrogen– This is an area we need to more in moving

forward. Economic implications are greater.

Documents

Managing P & N Nutrient Resources Agronomy In-service January 3, 2013 Greg LaBarge, Field Specialist, Agronomic Systems