1

A comparison of corn head harvest performance

2008 • 2009 • 2010

conducted by

J.S. Burris Burris Consulting LLC

Ames, Iowa November, 2010

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HARVEST LOSS SUMMARY COMBINED 2008 – 2010

Field Loss 2008-2010 with SE

Ox

bo

50

JD

60

0

JD

89

3

Ca

se

0

1

2

3

Un

its/A

cre

Head

3

HARVEST SYSTEM PERFORMANCE

J.S. Burris Burris Consulting LLC

Ames, Iowa November, 2010

INTRODUCTION Over the last two decades the seed corn industry has utilized the husk-on harvest system as originally

described by Stanfield (1986) and that was referred to as the "one step" harvesting system. More

specifically, the "one step" system includes a harvesting unit, which in many cases had been developed

for the sweet corn processing industry. These units remove the ear from the mother plant and elevate it

into a wagon or container. They do not have any husking capability. In principle, harvesting the ear with

the husk intact will reduce the mechanical damage to the seed during transportation from the field to the

plant. The units may also incorporate snapping rolls modified to improve picking efficiency of high

moisture corn, and especially under wet field conditions. Further published reports of the use of non-

husking harvest equipment were reported by Kaltenberg (1986), and reviewed by Wahls, Brown, Meyer

and Brown (1987) in 1987.

As with any new technology, over time the original designs have been modified and performance figures

often vary depending upon the test and the conditions under which the testing is conducted. During this

period, many changes have occurred both in the genetics that are harvested and in the harvest equipment.

Many headers in use today are multi-panel with 12 to 13 rows. In addition, ground speed has increased as

unit horsepower and harvest speed demands have increased. Recent harvest seasons have seen an

increase in the amount of shell corn losses as shown in the photo from 2007. These volunteer corn fields

have served as a stark reminder of the amount of valuable seed being left in the field. Since there is very

little published information on the performance of the current technology, thus, the current study was

initiated.

This report is the summary report of a two year study which included seed fields in several Midwest states

and representing different genetics and moisture levels. The 2008 study included direct comparisons of

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Postharvest seed field Eastern Iowa, September, 2007

Oxbo and competitive headers from Case and Drago. The 2009 study expanded the field locations and

included two types of John Deere heads and also included additional data for the Case header.

PROTOCOL The general protocol will be the same at each location and will consist of field loss and machine

performance data. Fields will be provided by the contract seed producers and their respective seed

companies. The fields will represent normal agronomic practices appropriate for seed production. The

planting patterns may vary but will in most cases be either 30 or 20 inch rows and the hybrids chosen will

represent both easy and difficult harvesting types. The fields will be scouted prior to the harvest and

experimental sections of each field will be identified so as to provide representative yet uniform plant

material. For statistical purposes, the experimental samples will be considered as completely random

within each replication. All equipment will be operated in a manner that would result in optimum

performance balancing production rates with maximized seed quality and minimum field loss.

Field Loss Prior to any harvest in 2008, the fields were sampled using a random quadrate of approximately 1/1000

acre. The quadrate will be placed randomly at 4 locations and any dropped ears or kernels will be

collected (male plants will be examined for viable kernels). These samples resulted in virtually no

dropped ears and thus the preharvest sampling was omitted in 2009.

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Following harvest by each unique harvester, unit field loss estimates will be made by carefully gleaning

either 4 or 8 randomly selected quadrates for loose kernels and ear portions with kernels attached.

Estimates of kernel number and weights (2008) were made for both portions and for the total. Total

gleaned field losses will be calculated using the seed number value and converting it to a unit value

(80,000 kernels/unit) based upon female acreage.

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RESULTS Field Performance 2008 Belt vs Steel Gathering Chains After the initial conversion to the husk-on harvesting system one of the first equipment variables that was

considered for change were the gathering chains from the rubber belts used by the sweetcorn industry to

the steel chains common on grain combines. The sweetcorn industry has continued to use the rubber belts

as a way to reduce damage on field loss. Unfortunately definitive data comparing belt or chain gathering

units has been difficult to obtain until this study.

Oxbo chains vs belts with SE

Belts Chains 0.0

0.5

1.0

1.5

2.0

Un

its

/ac

Header

Position

Left

MIddle

Right

Figure 1, Story county, Iowa at 34% mc onSept. 24, 2008

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When compared side-by-side on similar heads in the same field, the differences between the two units

would be expected to be minimal. The field where the above comparison was made was at 34% moisture

content and the field weed control was good, Figure 1. When the comparison is made across head

position, the Belt vs Chain comparison is 32.6 vs 51.7 lb/ac and the difference is significant at the 5%

level. Within the header configuration, the position on the head did not impact the field loss. Thus, even

when all settings are optimized there is a measurable difference, and in addition to the field losses there is

likely an impact on seed quality. Even though the difference is minimal, maximizing yield and seed

quality should justify the use of the belt gathering system. In the comparisons that follow, all Oxbo

heads were equipped with belt gathering systems and the other heads were typically fitted with steel

gathering chains.

Oxbo vs Case The comparison of Oxbo and Case heads was made in a seed field in Nebraska and all settings on both

heads were made to maximize performance. The harvested sections were adjacent and at approximately

26% mc and thus field losses would be expected to be somewhat higher than the first comparison which

were at a higher moisture content (34%), Figure 2. Across position, the Oxbo vs Case comparison

resulted in 23.4 vs 94.3 lb/ac where the difference is significant at the 1% level. At this somewhat lower

moisture content, the position on the head was significant with the maximum loss occurring in the center

of the head, 21.3, 106.4, 48.9 lbs., respectively, for left, middle, and right positions. The graphical

contrast makes the differences clear and the new head advantage averaged approximately 1.3 (80K) units

per acre. Any suggestion that the seed left in the field are composed of large and small rounds is not

supported by the seed size estimates of the shelled seed, which was closer to that of a flat size rather than

a large round. Further, these comparisons were made with the harvesters operated at approximately 5

mph and the losses would likely be greater at higher ground speeds. It should also be noted that the

graphical scale is twice the magnitude of the initial trial at a higher moisture content.

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Field Loss with SE

Oxbo 51230 Case NH 0.0

0.5

1.0

1.5

2.0

2.5

3.0

Un

its

/ac

Header

Position

Left

MIddle

Right

Figure 2. Buffalo county, Nebraska, 26%mc Sept. 30, 2008

Oxbo vs Drago The Drago corn head is manufactured in Italy and is a recent introduction to the Midwest. Its primary

market has been the commodity corn market but it has also gained a presence in the seed corn harvest

market. One of the primary features is the “self adjusting” stripper plates which are claimed to reduce

loss and damage. In this comparison, the seed field was approximately 24% moisture content and the

inbred had rather short ears. The short ears were pulled down into the snapping rolls and cut into 1 to 2

inch segments. This resulted in a dramatic level of seed loss, Figure 3, as compared to the other locations

and heads. The overall average loss for the Oxbo head was 56 lb/ac while the Drago head resulted in a

430 lb/ac loss. Approximately ¼ of the Drago loss was related to the short cob sections with seed

attached and the remaining was shell corn on the ground. These convert to a unit (80K) loss of 1.3 for the

Oxbo and 9.8 for the Drago per acre, which at current wholesale prices would easily pay for the Oxbo

head.

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Field loss head comparison, Whiteside county IL, Oct, 2008

Field Loss with SE

Oxbo 51230 Drago 0

5

10

15

Un

its

/ac

Header

Position

Left

Middle

Right

Figure 3. Whiteside county, Illinois 24% moisture October 9, 2008

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Field Performance 2009

The experimental design was modified in 2009 with an increase in the number of quadrates sampled and

with a significant increase in the number of side-by-side comparisons and field locations. In addition to

the Oxbo 51230, the study included two styles of John Deere heads the older version being the JD893 and

the new version being the JD 600 series, and finally Case NH heads were also tested. Regardless of

weather the results are reported as seed number or as seed unit values the results are similar.

The Oxbo head resulted in the lowest field losses and was significantly better than any of the other heads

studied. The new (600 Series) of John Deere was the next best and was only slightly better than the older

(893 Series) which was slightly better than the Case unit.

There are clearly large agronomic differences between the 2008 and 2009 seasons, thus it is difficult to

make contrasts across the years. However, it is note worthy that when measured in Units/ac the Oxbo

performance was similar in both years. It would seem reasonable to assume that the loss of more than 2

units of seed production per acre would justify the improvement gains related to the Oxbo header.

Example of field loss resulting from JD 893 header in 38% moisture seed corn.

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Field Performance 2010

Field conditions in 2010 were generally good with rapid dry-down of grain and seed and normal weed

control conditions. Because not all heads were compared side-by-side at all locations a linear analysis of

variance was used to maximize the power to differentiate header performance.

The experimental design for 2010 was similar to 2009 and continued to include eight replications and the

number of locations was increased somewhat. The majority of the samples were from hybrid production

fields with only a few seed fields represented. Since most modern hybrids are small seeded and the

agronomic performance of many seed parents is very much improved, performance in either field

conditions is considered similar. In addition to the Oxbo 50 Series, the study included two styles of John

Deere heads the older version being the JD893 and the new version being the JD 600 series. The results

are reported as seed units per acre to provide a more tangible numerical value and to make the ANOVA

more easily reviewed.

Again in 2010 the Oxbo head resulted in the lowest field losses and was significantly better than any of

the other heads studied. The new (600 Series) of John Deere was the next best and was slightly better

than the older (893 Series). Over the years Oxbo heads have consistently averaged less than one unit/acre

field loss and significantly out performed the competition.

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Field Loss 2008-2010 with SE

Ox

bo

50

JD

60

0

JD

89

3

Ca

se

0

1

2

3

Un

its

/Ac

re

Head

CONCLUSIONS The head-to-head comparisons presented are corroborated by additional individual trials with the Oxbo

head that confirm the performance noted in the samples gathered over a three year period. It is clear that

a head designed for seed harvest will perform better than a unit designed for grain harvest and the amount

of saved seed will provide a quick return on the investment. The following conclusions are supported by

the data from three years of study:

♦ Belt gathering systems are superior to chain gathering and result in less field loss and likely less

mechanical damage.

♦ The Oxbo 50 Series produces significantly less field loss than the Case NH 2412 and saved nearly

1.5 units of seed per acre in the 2008 study..

♦ The Drago head performed very poorly in 2008 with an inbred with short ears and resulted in large

quantities of shelled seed and cob portions left in the field.

♦ Over three years the Oxbo 50 Series is superior to either the new John Deere (JD 600 series) or the

older John Deere 893 series heads with an advantage of approximately one unit/ac.

♦ There should be a financial incentive to the harvester operator to insure maximum seed yield with

a minimal amount of damage.

♦ Harvest equipment should be selected for its ability to gently handle diverse seed genetics over a

range of moisture contents and under various conditions

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LITERATURE CITED Brown C., D. Brown, M.D. Meyer, H. Wahls. 1987. Alternative harvesting systems for seed corn. Proc Seed Tech Conf Iowa State Univ. 9:113-149. Kaltenberg, J. 1986. Application of new technology for harvesting and husking of seed corn. Proc. Seed Tech. Conf. Iowa State Univ. 8:103-110. Stanfield, Z.A. 1986. One-step husking system for seed corn. Proc Corn Sorghum Res Conf. 41:121-133. Stott, T. 1967. Machinery for harvesting seed fields. Proc Corn Sorghum Res Conf. 22:59.

Appendix Complete 4 Rep ANOVA 2008 Oxbo Chain vs Belt Location Story County, Iowa Heads 1 = Oxbo 51320 with belt 2 = Oxbo 51320 with chains Position 1 = Header Left 2 = Header Center 3 = Header Right Units = number of seed per ac/80,000 Analysis of Variance Table for Units Source DF SS MS F P Header 1 1.27882 1.27882 3.22 0.0927 Position 2 0.29992 0.14996 0.38 0.6915 Rep 3 0.14035 0.04678 0.12 0.9482 Header*Position 2 0.37806 0.18903 0.48 0.6300 Error 15 5.95010 0.39667 Total 23 Note: SS are marginal (type III) sums of squares Grand Mean 1.0025 CV 62.82 Means of Units for Header Header Mean 3 0.7717 4 1.2333 Observations per Mean 12 Standard Error of a Mean 0.1818 Std Error (Diff of 2 Means) 0.2571

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Means of Units for Position Position Mean 1 1.1563 2 0.9575 3 0.8938 Observations per Mean 8 Standard Error of a Mean 0.2227 Std Error (Diff of 2 Means) 0.3149 Means of Units for Header*Position Header Position Mean 3 1 0.7900 3 2 0.6950 3 3 0.8300 4 1 1.5225 4 2 1.2200 4 3 0.9575 Observations per Mean 4 Standard Error of a Mean 0.3149 Std Error (Diff of 2 Means) 0.4454

Oxbo vs Case Location Buffalo County, Nebraska Heads 1 = Oxbo 12 row 30” with belt 2 = Case NH 2412 Position 1 = Header Left 2 = Header Center 3 = Header Right Units = number of seed per ac/80,000 Analysis of Variance Table for Units Source DF SS MS F P Header 1 9.95882 9.95882 20.79 0.0004 Position 2 9.12782 4.56391 9.53 0.0021 Rep 3 0.26167 0.08722 0.18 0.9069 Header*Position 2 2.47626 1.23813 2.58 0.1085 Error 15 7.18503 0.47900 Total 23 Note: SS are marginal (type III) sums of squares Grand Mean 1.0700 CV 64.68 Means of Units for Header Header Mean 1 0.4258 2 1.7142 Observations per Mean 12 Standard Error of a Mean 0.1998 Std Error (Diff of 2 Means) 0.2825 Means of Units for Position Position Mean 1 0.4100

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2 1.8937 3 0.9063 Observations per Mean 8 Standard Error of a Mean 0.2447 Std Error (Diff of 2 Means) 0.3460 Means of Units for Header*Position Header Position Mean 1 1 0.1675 1 2 0.8650 1 3 0.2450 2 1 0.6525 2 2 2.9225 2 3 1.5675 Observations per Mean 4 Standard Error of a Mean 0.3460 Std Error (Diff of 2 Means) 0.4894

Oxbo vs Drago Location Whiteside County, Illinois Heads 3 = Oxbo 51320 with belt 5 = Drago Position 1 = Header Left 2 = Header Center 3 = Header Right Units = number of seed per ac/80,000 Analysis of Variance Table for Units Source DF SS MS F P Header 1 434.606 434.606 41.77 0.0000 Position 2 24.336 12.168 1.17 0.3373 Rep 3 87.311 29.104 2.80 0.0761 Header*Position 2 50.229 25.115 2.41 0.1234 Error 15 156.076 10.405 Total 23 Note: SS are marginal (type III) sums of squares Grand Mean 5.6046 CV 57.55 Means of Units for Header Header Mean 3 1.3492 5 9.8600 Observations per Mean 12 Standard Error of a Mean 0.9312 Std Error (Diff of 2 Means) 1.3169 Means of Units for Position Position Mean 1 6.4450 2 4.1888 3 6.1800 Observations per Mean 8 Standard Error of a Mean 1.1405

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Std Error (Diff of 2 Means) 1.6128 Means of Units for Header*Position Header Position Mean 3 1 0.965 3 2 1.965 3 3 1.118 5 1 11.925 5 2 6.413 5 3 11.243 Observations per Mean 4 Standard Error of a Mean 1.6128 Std Error (Diff of 2 Means) 2.2809

ANOVA 2&3 Rep and Nonpaired Comparisons Oxbo vs Case Location Buffalo County, Nebraska Heads 1 = Oxbo 12 row 30” with belt 2 = Case NH 2412 Position 1 = Header Left 2 = Header Center 3 = Header Right Units = number of seed per ac/80,000 Analysis of Variance Table for Units Source DF SS MS F P Header 1 0.20541 0.20541 0.56 0.4883 Position 2 0.28032 0.14016 0.38 0.7012 Rep 1 0.00021 0.00021 0.00 0.9819 Header*Position 2 0.02322 0.01161 0.03 0.9691 Error 5 1.83714 0.36743 Total 11 Note: SS are marginal (type III) sums of squares Grand Mean 0.3592 CV 168.77 Means of Units for Header Header Mean 1 0.2283 2 0.4900 Observations per Mean 6 Standard Error of a Mean 0.2475 Std Error (Diff of 2 Means) 0.3500 Means of Units for Position Position Mean 1 0.2950 2 0.2125 3 0.5700 Observations per Mean 4 Standard Error of a Mean 0.3031 Std Error (Diff of 2 Means) 0.4286

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Means of Units for Header*Position Header Position Mean 1 1 0.1600 1 2 0.0300 1 3 0.4950 2 1 0.4300 2 2 0.3950 2 3 0.6450 Observations per Mean 2 Standard Error of a Mean 0.4286 Std Error (Diff of 2 Means) 0.6062

Oxbo Location Tylor , Missouri Heads Oxbo 51320 with belt Position 1 = Header Left 2 = Header Center 3 = Header Right Units = number of seed per ac/80,000 Analysis of Variance Table for Units Source DF SS MS F P Position 2 0.69095 0.34548 4.31 0.0691 Rep 3 0.21030 0.07010 0.87 0.5047 Error 6 0.48085 0.08014 Total 11 Note: SS are marginal (type III) sums of squares Grand Mean 0.3950 CV 71.67 Means of Units for Position Position Mean 1 0.1700 2 0.7275 3 0.2875 Observations per Mean 4 Standard Error of a Mean 0.1415 Std Error (Diff of 2 Means) 0.2002

Complete 8 Rep ANOVA 2009 Analysis of Variance Table for Units Source DF SS MS F P Loc 18 234.59 13.0330 1.53 0.0815 Head 3 102.45 34.1515 4.00 0.0084 Rep 7 43.54 6.2194 0.73 0.6486 Error 251 2145.10 8.5462 Total 279 Note: SS are marginal (type III) sums of squares Grand Mean 1.7554 CV 166.54

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ANOVA Oxbo vs John Deere 612 Series Analysis of Variance Table for Units Source DF SS MS F P Loc 16 108.676 6.7923 1.00 0.4638 Head 1 31.136 31.1355 4.57 0.0343 Rep 7 31.630 4.5186 0.66 0.7030 Error 143 974.527 6.8149 Total 167 Note: SS are marginal (type III) sums of squares Grand Mean 1.6712 CV 156.20 Means of Units for Loc Loc N Mean SE Loc N Mean SE 1 24 0.0266 0.5460 11 8 2.0688 0.9898 2 8 1.1859 0.9898 12 8 1.7172 0.9898 3 8 3.7328 0.9898 13 16 1.7891 0.6526 5 8 1.4828 0.9898 14 8 1.8188 0.9898 6 8 0.9594 0.9898 16 8 1.4906 0.9898 7 8 0.9281 0.9898 17 8 2.8578 0.9898 8 16 1.8203 0.6526 18 8 2.2172 0.9898 9 8 1.5219 0.9898 19 8 1.4594 0.9898 10 8 1.3344 0.9898 Means of Units for Head Head N Mean SE 1 136 0.9072 0.2239 2 32 2.4353 0.6790

ANOVA Oxbo vs John Deere 893 Series Analysis of Variance Table for Units Source DF SS MS F P Loc 18 193.56 10.7531 1.41 0.1309 Head 1 70.72 70.7170 9.24 0.0027 Rep 7 29.43 4.2042 0.55 0.7961 Error 213 1629.62 7.6508 Total 239 Note: SS are marginal (type III) sums of squares Grand Mean 1.4153 CV 195.43

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Means of Units for Loc Loc N Mean SE Loc N Mean SE 1 8 1.0089 0.9999 11 16 3.0547 0.6915 2 16 2.3711 0.6915 12 16 1.5469 0.6915 3 8 3.6026 0.9999 13 8 1.3761 0.9999 4 8 0.2021 0.9999 14 16 0.9414 0.6915 5 16 0.6680 0.6915 15 8 0.4911 0.9999 6 8 0.8292 0.9999 16 8 1.3604 0.9999 7 16 1.3437 0.6915 17 16 2.7930 0.6915 8 8 0.8604 0.9999 18 16 2.0742 0.6915 9 16 0.7461 0.6915 19 16 1.2344 0.6915 10 16 0.3867 0.6915 Means of Units for Head Head N Mean SE 1 136 0.7814 0.2507 3 104 2.0492 0.3154

ANOVA Oxbo vs Case Series Analysis of Variance Table for Units Source DF SS MS F P Loc 16 67.640 4.2275 1.03 0.4346 Head 1 14.895 14.8948 3.62 0.0597 Rep 7 15.113 2.1590 0.52 0.8149 Error 119 490.209 4.1194 Total 143 Note: SS are marginal (type III) sums of squares Grand Mean 1.8720 CV 108.42 Means of Units for Loc Loc N Mean SE Loc N Mean SE 1 8 1.3398 0.8789 11 8 2.2695 0.8789 2 8 1.3867 0.8789 12 8 1.9180 0.8789 3 8 3.9336 0.8789 13 8 1.7070 0.8789 5 8 1.6836 0.8789 14 8 2.0195 0.8789 6 8 1.1602 0.8789 16 8 1.6914 0.8789 7 8 1.1289 0.8789 17 8 3.0586 0.8789 8 16 1.1914 0.5074 18 8 2.4180 0.8789 9 8 1.7227 0.8789 19 8 1.6602 0.8789 10 8 1.5352 0.8789 Means of Units for Head Head N Mean SE 1 136 0.9072 0.1740 4 8 2.8369 0.9998

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Complete 8 Rep ANOVA 2010

ANOVA Oxbo vs John Deere 612 Series Analysis of Variance Table for Seed Source DF SS MS F P Head 1 9623 9622.55 6.17 0.0133 Rep 7 5457 779.52 0.50 0.8347 Error 455 709431 1559.19 Total 463 Note: SS are marginal (type III) sums of squares Grand Mean 23.735 CV 166.37 Analysis of Variance Table for Units Source DF SS MS F P Head 1 37.59 37.5944 6.17 0.0133 Rep 7 21.31 3.0448 0.50 0.8347 Error 455 2771.20 6.0906 Total 463 Note: SS are marginal (type III) sums of squares Grand Mean 1.4836 CV 166.35

MEANS Means of Seed for Head Head N Mean SE 1 304 18.944 2.2647 2 160 28.525 3.1217 Means of Seed for Rep Rep N Mean SE 1 58 27.694 5.2193 2 58 25.504 5.2193 3 58 28.745 5.2193 4 58 20.004 5.2193 5 58 25.935 5.2193 6 58 20.469 5.2193 7 58 22.004 5.2193 8 58 19.521 5.2193

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Means of Units for Head Head N Mean SE 1 304 1.1841 0.1415 2 160 1.7830 0.1951 Means of Units for Rep Rep N Mean SE 1 58 1.7310 0.3262 2 58 1.5942 0.3262 3 58 1.7967 0.3262 4 58 1.2504 0.3262 5 58 1.6211 0.3262 6 58 1.2795 0.3262 7 58 1.3754 0.3262 8 58 1.2203 0.3262

ANOVA Oxbo vs John Deere 893 Series Analysis of Variance Table for Seed Source DF SS MS F P Head 1 17559 17559.2 9.50 0.0022 Rep 7 5206 743.7 0.40 0.9008 Error 423 781923 1848.5 Total 431 Note: SS are marginal (type III) sums of squares Grand Mean 25.925 CV 165.84 Analysis of Variance Table for Units Source DF SS MS F P Head 1 68.58 68.5769 9.50 0.0022 Rep 7 20.34 2.9051 0.40 0.9008 Error 423 3054.39 7.2208 Total 431 Note: SS are marginal (type III) sums of squares Grand Mean 1.6204 CV 165.83

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MEANS Means of Seed for Head Head N Mean SE 1 304 18.944 2.4659 3 128 32.906 3.8002 Means of Seed for Rep Rep N Mean SE 1 54 30.826 5.9231 2 54 26.363 5.9231 3 54 27.437 5.9231 4 54 23.400 5.9231 5 54 31.418 5.9231 6 54 23.437 5.9231 7 54 22.659 5.9231 8 54 21.863 5.9231 Means of Units for Head Head N Mean SE 1 304 1.1841 0.1541 3 128 2.0567 0.2375 Means of Units for Rep Rep N Mean SE 1 54 1.9267 0.3702 2 54 1.6478 0.3702 3 54 1.7149 0.3702 4 54 1.4626 0.3702 5 54 1.9637 0.3702 6 54 1.4649 0.3702 7 54 1.4163 0.3702 8 54 1.3665 0.3702

ANOVA Combined 2008-2010 Head

1 = Oxbo 2 = JD 600 Series 3 = JD 893 Series 4 = Case

Analysis of Variance Table for Seed Source DF SS MS F P Head 3 21801 7266.88 4.08 0.0070 Rep 7 9241 1320.20 0.74 0.6371 Error 589 1049205 1781.33 Total 599 Note: SS are marginal (type III) sums of squares Grand Mean 28.719 CV 146.96

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Analysis of Variance Table for Units Source DF SS MS F P Head 3 85.15 28.3832 4.08 0.0070 Rep 7 36.10 5.1571 0.74 0.6371 Error 589 4098.44 6.9583 Total 599 Note: SS are marginal (type III) sums of squares Grand Mean 1.7950 CV 146.95 Means of Seed for Head Head N Mean SE 1 304 18.944 2.421 2 160 28.525 3.337 3 128 32.906 3.731 4 8 34.500 14.922 Means of Seed for Rep Rep N Mean SE 1 75 34.234 6.0523 2 75 26.407 6.0523 3 75 33.354 6.0523 4 75 25.660 6.0523 5 75 33.434 6.0523 6 75 24.847 6.0523 7 75 27.247 6.0523 8 75 24.567 6.0523 Means of Units for Head Head N Mean SE 1 304 1.1841 0.1513 2 160 1.7830 0.2085 3 128 2.0567 0.2332 4 8 2.1562 0.9326 Means of Units for Rep Rep N Mean SE 1 75 2.1397 0.3783 2 75 1.6505 0.3783 3 75 2.0847 0.3783 4 75 1.6039 0.3783 5 75 2.0897 0.3783 6 75 1.5530 0.3783 7 75 1.7030 0.3783 8 75 1.5356 0.3783