Plant-to-Plant Variability in Corn Production K.L. Martin, P.J. Hodgen, K.W. Freeman, Ricardo Melchiori, D.B. Arnall, R.K. Teal, R.W. Mullen, K. Desta,

Plant-to-Plant Variability in

Corn Production

Plant-to-Plant Variability in

Corn Production

K.L. Martin, P.J. Hodgen, K.W. Freeman, Ricardo Melchiori, K.L. Martin, P.J. Hodgen, K.W. Freeman, Ricardo Melchiori, D.B. Arnall, R.K. Teal, R.W. Mullen, D.B. Arnall, R.K. Teal, R.W. Mullen,

K. Desta, S.B. Phillips, J.B. Solie, M.L. Stone, K. Desta, S.B. Phillips, J.B. Solie, M.L. Stone, Octavio Caviglia, Fernando Solari, Agustin Bianchini, Octavio Caviglia, Fernando Solari, Agustin Bianchini, D.D. Francis, J.S. Schepers, J. L. Hatfield, W.R. RaunD.D. Francis, J.S. Schepers, J. L. Hatfield, W.R. Raun

Objectives

1. Evaluate by-plant corn grain yield variability over a range of production environments2. Determine the relationships among mean grain yield, standard deviation of yield, coefficient of variation of yield, and yield range3. Evaluate the relationship between NDVI and corn grain yields.

Objectives

1. Evaluate by-plant corn grain yield variability over a range of production environments2. Determine the relationships among mean grain yield, standard deviation of yield, coefficient of variation of yield, and yield range3. Evaluate the relationship between NDVI and corn grain yields.

Variability in by-plant corn grain yields

Variability in by-plant corn grain yields

Delayed and uneven emergence Delayed and uneven emergence variable depth of plantingvariable depth of planting double seed dropsdouble seed drops wheel compactionwheel compaction location of the seed within the furrowlocation of the seed within the furrow surface crustingsurface crusting random soil clodsrandom soil clods soil texture differencessoil texture differences variable distance between seedsvariable distance between seeds variable soil compaction around the seedvariable soil compaction around the seed insect damageinsect damage moisture availabilitymoisture availability variable surface residuevariable surface residue variable seed furrow closure variable seed furrow closure

Ames, IowaAmes, Iowa

2003 Corn DataFAO and National Corn Growers Association

2003 Corn DataFAO and National Corn Growers Association

Corn Grain Production Corn Grain Production Avg. YldAvg. Yld AreaAreaMg/haMg/ha million hamillion ha

WorldWorld 4.54.5 142 142 USAUSA 8.98.9 2828ArgentinaArgentina 6.46.4 2.32.3MexicoMexico 2.52.5 7.87.8

IowaIowa 9.8 9.8 4.84.8NebraskaNebraska 9.29.2 3.13.1OhioOhio 8.78.7 1.21.2VirginiaVirginia 7.27.2 0.20.2OklahomaOklahoma 7.87.8 0.10.1

MethodsMethods By-plant Corn Grain YieldsBy-plant Corn Grain Yields

ArgentinaMexicoIowaNebraskaOhioVirginiaOklahoma

Data collected: Data collected: Grain yield, yield range, standard deviation and coefficient of variation. Grain yield, yield range, standard deviation and coefficient of variation.

Transects: corn rows ranging from 8 to 30 m in lengthTransects: corn rows ranging from 8 to 30 m in length

Individual plants marked at most sites at or before V8 to ensure detection of Individual plants marked at most sites at or before V8 to ensure detection of barren, and/or lost plants at harvest (60-85 days later depending on the maturity)barren, and/or lost plants at harvest (60-85 days later depending on the maturity)

At the time plants were tagged, a tape measure was extended the length of the At the time plants were tagged, a tape measure was extended the length of the row and cumulative distances were recorded for each plantrow and cumulative distances were recorded for each plant

At most sites (based on row spacing) the area occupied by each plant was At most sites (based on row spacing) the area occupied by each plant was calculated. calculated.

Each plant determined to occupy half the distance to and from its nearest neighborEach plant determined to occupy half the distance to and from its nearest neighbor

Where:Where: AiAi is the area occupied by the ith plant is the area occupied by the ith plant Di-1,di,di+1Di-1,di,di+1 are the distances to the i-1, i, and i+1 plants are the distances to the i-1, i, and i+1 plants RR is the row spacing is the row spacing

Ears harvested individually, dried, and weighedEars harvested individually, dried, and weighed > one ear per plant , total weight was recorded on a by-plant basis> one ear per plant , total weight was recorded on a by-plant basis Sites where actual distances between plants were not recorded: Avg. distance Sites where actual distances between plants were not recorded: Avg. distance

occupied per plant was determined based on row spacing and total transect or row occupied per plant was determined based on row spacing and total transect or row distance and number of plants harvested per row. distance and number of plants harvested per row.

MethodsMethods

Rdddd

A iiiii

2211

Mean Yield vs Std. Dev.Mean Yield vs Std. Dev.

0

1000

2000

3000

4000

5000

6000

7000

0 5000 10000 15000 20000 25000

Mean Yield, kg/ha

Std

. De

v. Y

ield

, kg

/ha

Oklahoma

Iowa

Nebraska

Mexico

Argentina

Ohio

Virginia

StdDev =920.71 +5.16E-5 Yld2 - 2.7 E-9 Yld3

R2 = 0.498

Average corn grain yield plotted against the standard deviation from by-plant yield over 46 transects in Argentina, Mexico, Iowa, Nebraska, Ohio, Virginia, and Oklahoma.

Mean Yield vs. CVMean Yield vs. CV

0

10

20

30

40

50

60

70

0 5000 10000 15000 20000 25000

Mean Yield, kg/ha

CV

of

Yie

ld, %

Oklahoma

Iowa

Nebraska

Mexico

Argentina

Ohio

Virginia

CV = 38.9 - 4.14 x 10-12 Yld3

R2 = 0.203

Average corn grain yield plotted against the coefficient of variation from by-plant yields over 46 transects in Argentina, Mexico, Iowa, Nebraska, Ohio, Virginia, and Oklahoma.

Mean Yield vs. Yield RangeMean Yield vs. Yield Range

0

10000

20000

30000

40000

50000

0 5000 10000 15000 20000

Mean Yield, kg/ha

Yie

ld R

an

ge

, kg

/ha

Oklahoma

Iowa

Nebraska

Mexico

Argentina

Ohio

Virginia

YR = - 3.54 + 6.28E-9 Yld2- 202E-8 Yld3

R2 = 0.550

Average corn grain yield plotted against the by-plant yield range (maximum minus minimum yield) in 46 transects ranging from 10.5 to 30m in length, in Argentina, Mexico, Iowa, Nebraska, Ohio, Virginia, and Oklahoma.

Distance Averaged vs. ErrorDistance Averaged vs. Error

0

0.5

1

1.5

2

2.5

0 25 50 75 100 125

Distance Averaged Along Row, cm

No

rmal

ized

Err

or

Nebraska

Iowa

Oklahoma

Error = 0.966 + 1.22 e-Dist/27.7

R2 = 0.574Effect of averaging plant yields over a specified distance along the row on the absolute error incurred when using the average corn yield for estimating the by-plant yield. Yields were normalized by the average yield along the entire row.

Average corn grain yields plotted by plant, every 2 plants, every 3 plants and every 4 plants, using measured distances between plants, Ames, IA 2004.

MeasuredDistancesMeasuredDistances

Fixed DistancesFixed Distances

Average corn grain yields computed using fixed distances of 23.5, 47.0, 70.6, and 94.1 cm at Ames, IA 2004

NDVI vs Yield NDVI vs Yield NDVI versus corn grain yield determined for every 4 plants using linear regression and associated 95% confidence intervals, east row, Ames IA, 2004.

+/- 1000 kg/ha

Location StatisticsLocation Statistics

Minimum, maximum, mean, standard deviation, maximum/minimum and CV for by-plant corn grain yields from 46 transects in Argentina, Mexico, Iowa, Nebraska, Ohio, Virginia, and Oklahoma, 2002-2004.________________________________________________________________________________________________________

Location Years Transects Min Yield Max Yield Mean Yield Stdev Max/Min CV------------------------ kg ha-1----------------------- %

El Batan, Mexico 2002 3 606 9440 4268 1935 22.4 45.3OK, <6000 kg ha-1 2003-4 12 1128 9169 4652 1724 10.0 37.2

OK, >6000 kg ha-1 2003-4 8 1947 14120 7050 2167 11.6 30.5

Ames, IA, Shelton, NE 2004 4 1872 21173 8320 3660 14.1 46.0

Wooster, OH 2004 1 2066 19458 9759 4367 9.4 50.2

Parana, Argentina 2003 9 2806 28058 11478 4211 15.0 36.8Painter, VA 2003 4 4753 24552 11943 3171 5.2 26.7

Phillips, NE 2004 5 7098 21492 14383 2926 3.2 20.3--------------------------------------------------------------------------------------------------------------

All Sites 2002-04 46 2752 17281 8495 2765 11.1 34.3________________________________________________________________________________________________________

44 bu/ac

SummarySummary Errors associated with predicting yield at V8 Errors associated with predicting yield at V8

were dwarfed in comparison to the recorded were dwarfed in comparison to the recorded by-plant yield differencesby-plant yield differences

Can N management at this scale help since Can N management at this scale help since yield potential can be predicted. yield potential can be predicted.

By-plant nutrient management could be By-plant nutrient management could be eliminated by developing production systems eliminated by developing production systems that homogenized plant stands, and that homogenized plant stands, and emergence emergence

Over all sites, plant-to-plant variation in corn Over all sites, plant-to-plant variation in corn grain yield averaged 2765 kg/ha (44.1 bu/ac). grain yield averaged 2765 kg/ha (44.1 bu/ac). Sites with the highest average corn grain yield Sites with the highest average corn grain yield (11478 and 14383 kg/ha, Parana Argentina, (11478 and 14383 kg/ha, Parana Argentina, and Phillips, NE), had plant-to-plant variation in and Phillips, NE), had plant-to-plant variation in yields of 4211 kg/ha (67 bu/ac) and 2926 kg/ha yields of 4211 kg/ha (67 bu/ac) and 2926 kg/ha (47 bu/ac)(47 bu/ac)