Research Challenges from Research Challenges from and and forfor High Yield Growers High Yield Growers

International Conference on Precision Agriculture

Minneapolis, MNJuly 26, 2004

Paul FixenPotash & Phosphate Institute

Scientists andScientists andfarmersfarmers

Is this session appropriate for a precision Is this session appropriate for a precision agriculture conference?agriculture conference?

Precision in management gets more Precision in management gets more critical as yield potential climbs …critical as yield potential climbs …

- agronomic reasons- agronomic reasons- environmental reasons- environmental reasons

Summary:Summary:Research challenges from high yield growers Research challenges from high yield growers

A large gap exists between maximum attainable and typical yields

Observing the practices of high yield growers through the lens of scientific principles and controlled research can be revealing and lead to researchable questions for scientistsscientists and farmersfarmers

Modern technologies should facilitate narrowing the gap between attainable and typical yields

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1965 1970 1975 1980 1985 1990 1995 2000

Year

Corn

yie

ld, bu/A

Exploitable yield potential in cornExploitable yield potential in corn

IA State Average1.7 bu/A/yr

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1965-19912.0 bu/A/yr

H. WarsawSaybrook, IL

F. ChildsManchester, IA

20 bu/A/yr

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Iowa exampleIowa example

IA Contest Winners

Top corn yields from researchers in Top corn yields from researchers in 1982 1982

Dr. Roy FlanneryDr. Roy FlanneryNew JerseyNew Jersey

338 bu/A338 bu/A

Dr. Sterling OlsenDr. Sterling OlsenColoradoColorado

332 bu/A332 bu/A

From Saybrook, IL to Manchester, IAFrom Saybrook, IL to Manchester, IA

Manchester, IA

Saybrook, IL

Growing season precip: very similar at 27-28”Growing degree Days: Manchester - 2980

Urbana – 3513

Property Childs Warsaw Soil type Kenyon loam Parr silt loamTaxonomy Typic Hapludolls Oxyaquic ArgiudollsOrg. mat., % 5.5-6.0 4.5-5.8pH 5.3-6.1 6.0P1, ppm 126 (VH) 81 (VH)K, ppm 374 (VH) 400 (VH)

Source: Childs – Murrell and Childs, 2000; Smith,2000; Dobermann, 2002; Warsaw – PPI, 1986.

From Saybrook, IL to Manchester, IA: From Saybrook, IL to Manchester, IA: Soil OMSoil OM

Manchester, IA

Saybrook, IL

Depth, In Childs Warsaw-light Warsaw-dark Organic matter, % 0-6 5.6 5.8 4.5 6-12 4.5 4.9 3.9 12-18 3.0 3.2 4.3 18-24 --- 1.4 4.3 24-30 --- 0.8 3.8 30-36 --- 0.6 3.6

Source: Childs data – Dobermann, 2002. Warsaw data – PPI, 1977.

Warsaw: 20 years of intensively managed continuous corn Childs: 35 years of intensively managed continuous corn

From Saybrook, IL to Manchester, IA: From Saybrook, IL to Manchester, IA: PracticesPractices

Manchester, IA

Saybrook, IL

Practice Childs Warsaw Fall tillage Mini MP 14” deep CH 14” deepHybrid 2001-34M95; 2002-34N44 FS 854Harv. Population 34,000 - 40,000 36,000Row spacing 2001-30”; 2002-20” 28”Manure High rates in past 20 T/A annually

Fall P2O5+K2O none 250+250Fall N, lb/A 50(UAN) 45(DAP)Preplant N 250(NH3 + sep. stab.) 300(UAN)+ 100(AS)Starter, N+P2O5+K2O 6+15+15+ACA 26+26+26Popup, N+P2O5+K2O 4+9+4 nonePostplant N 50(UAN) 75(UR)2.5-4’ tall N 50(UAN+Guardian) None Fert N, lb/A 410(1.0 bu/lb) 546(0.7 bu/lb) Other nutrients Boron Sulfur

Research challenges: Which practices are Research challenges: Which practices are critical and at what level?critical and at what level?

Determination of site-specific attainable yield estimates (crop models)

Carbon cycling – crop and environmental impacts Crop rotation vs monoculture Tillage requirements … no till/strip till Minimum N requirements, NH4

+ vs NO3-, timing

Minimum soil test P and K requirements Role of subsoil fertility, organic matter, etc. (P. Nowak)(P. Nowak)

Role of manure application Role of secondary and micronutrients Importance of starter fertilizer (0.5% P at V3-V4 for

max kernel initiation/ear)

http://www.hybridmaize.unl.edu/http://www.hybridmaize.unl.edu/

Better Crops (2004, No. 1)

Real time yield prediction of current seasonReal time yield prediction of current season

U. of Nebraska EI Study - Lincoln

July 25, 2004

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349

279

Soil Test P and K requirements for Soil Test P and K requirements for very high yields: Classical theory very high yields: Classical theory

For soil immobile nutrients like P or K, the STL vs % yield relationship should not vary with site yield potential unless plant population increases enough for adjacent roots to compete with each other for P and K (Bray, 1954; Bray, 1963).

Roots normally occupy less than 1% of soil volume (Barber, 1984) … an increase in size of the root system translates into a greater volume of soil P or K being available for uptake.

As long as the size of the root system increases proportionally with yield, a higher yielding crop should not need a higher P or K concentration at the root surface … should not require a higher soil test level.

Soil Test P and K requirements for very Soil Test P and K requirements for very high yields: Conditions that could lead to high yields: Conditions that could lead to

higher requirementshigher requirements Shoot growth increases that exceed root growth

increases as yields climb Redistribution of roots from the surface soil to a low P or

K subsoil soil factors (organic matter, pH, structure, etc.) varietal factors – vertical vs lateral rooting tendencies

Each % increase in yield has greater economic value … want to be further up the response curve

Is “subsoil” fertility more important to today’s Is “subsoil” fertility more important to today’s high yield potential “stay-green” hybrids?high yield potential “stay-green” hybrids?

Probably taking up nutrients later in the season when surface soils are dryer

Higher % of active roots located deeper in profile

36 Days

8 Weeks Mature

Source: Weaver, 1926 Is manure important Is manure important because it moves P because it moves P

into subsoils?into subsoils?

Impact of Impact of hybridhybrid on the influence of on the influence of NN rate rate on yield response to plant on yield response to plant populationpopulation

S.R. Olsen, reported by W. M. Stewart, 2000

27K vs 38K 39K vs 46K

Colorado

Risk/benefit evaluation of yield Risk/benefit evaluation of yield improvement phasesimprovement phases

Phase Yield benefit and risk

Fully implement standard agronomic BMPs (site-specific) Minor

Experiment with optimizing setssets of easily controlled factors for higher yield levels

Ex: population, nutrients, hybrid

Moderate

Experiment with system-level changes, then re-optimize

Ex: tillage, row spacing, rotation

Major

Long-termLong-term soil quality improvement with continuous re-optimization

Ex: organic matter, subsoil properties, tilth

Long-term major

Summary:Summary:Research challenges from high yield growers Research challenges from high yield growers

A large gap exists between maximum attainable and typical yields

Observing the practices of high yield growers through the lens of scientific principles and controlled research can be revealing and lead to researchable questions for scientistsscientists and farmersfarmers.

Modern technologies should facilitate narrowing the gap between attainable and typical yields Simulation models to help define attainable yields and researchable

questions Improved weather data and management tools Site-specific technologies for greater efficiency Biotechnology for yield protection … and building

Research Challenges from Research Challenges from High Yield GrowersHigh Yield Growers

InfoAg 2003Indianapolis, IN

August 1, 2003

Paul Fixen

Potash & Phosphate Institute