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THE UNIVERSITY OF ILLINOIS commercial forage testing program has been testing
public and private forages for over 51 years. The initial purpose was to evaluate
the many public varieties available, today public varieties are far out numbered
by private varieties. This year 44 seed companies are participating in the 2002
trials.
The purpose of this commercial forage testing program is to provide unbiased,
objective, and accurate testing of all varieties entered. The tests are conducted
on as uniform a soil as is available in the testing area. Small plots are used
to reduce the chance ofsoil and climatic variations occurring between one variety
plot and another.
The results of these tests should help you judge the merits of varieties in
comparison with other private and public varieties. Because your soils and management
may differ from those of the test location, you may wish to plant variety strips
of the higher-performing varieties on your farm. The results printed in this
circular should help you decide which varieties to try.
Selection of entries Forage producers in Illinois and surrounding
states were invited to enter varieties in the 2002 Illinois forage performance
trials. Entrants were required to provide seed in a commercially available container
to the University of Wisconsin for distribution to other public testing programs.
This is to ensure performance is not affected by seed source and to avoid each
entrant the cost of sending a commercial bag of seed to each program.
To help finance the testing program, a fee of $450 per location per 4 years
was charged for each variety entered by the seed producer. Most of these varieties
are commercially available, but some experimental varieties were also entered.
A total of 140 varieties were tested in 2002.
Number and location of tests In 2002, tests were conducted at 5 locations
throughout the state (see map on pg. 4). These sites represent the major soils
and dairy producing areas of the state.
Field plot design Entries of each test were replicated four times in a randomized
complete block. Plot size was 23 feet by 3 feet andend trimmed at each harvest
to obtain a 19 foot long plot.
Fertility and weed control All test locations were managed at a high level
of fertility for each crop. Herbicides were used at all testlocations for weed
control.
Method of planting and harvesting All trials were seeded with a five row
seeder modified to accommodate small plot seeding. Plots were seeded at 18 pounds
per acre. Harvests were taken with a custom built flail chopper equipped with
electronic data gathering equipment.
Yield Forage yield is reported in tons dry matter per acre. Yields
were converted to a dry matter basis by estimating percent moisture within
each trial.
It is impossible to obtain an exact measure of performance when conducting
any test of plant material. Harvesting efficiency may vary, soils may not be
uniform, and many other conditions may produce variability. Results of repeated
tests are more reliable than those of a single year or a single-strip test.
When one variety consistently out yields another at several test locations and
over several years of testing, the chances are good that this difference is
real and should be considered in selecting a variety.
As an aid in comparing alfalfa varieties within a single trial, certain statistical
tests have been devised. One of these tests, the least significant difference
(L.S.D.), when used in the manner suggested by Carmer and Swanson1 is quite
simple to apply and is more appropriate than most other tests. When two entries
are compared and the difference between them is greater than the tabulated L.S.D.
value, the entries are judged to be "significantly different."
The L.S.D. is a number expressed in tons dry matter per acre and presented following
the average yield. An L.S.D. of 5% is shown. Add the L.S.D. value to the trial
mean. Every variety with a greater yield than the resulting number is 'statistically
better than average. Consider the merits of the varieties in this group when
making varietal selections.
To make the best use of the information presented in this circular and to avoid
any misunderstanding or misrepresentation of it, the reader should consider
an additional caution about comparing entries. Readers who compare entries in
different trials should be extremely careful, because no statistical tests are
presented for that purpose. Readers should note that the difference between
a single entry's performance at one location and its performance at another
is caused primarily by environmental effects and random variability. Furthermore,
the difference between the performance of entry A in one trial and the performance
of entry B in another trial is the result not only of environmental effects
and random variability, but of genetic effects as well.
1Carmer, S.G. and M.R. Swanson. "An Evaluation of Ten
Pairwise Multiple Comparison Procedures by Monte Carlo Methods."
Journal of American Statistical Association 68:66-74. 1983.
2002 Growing Season Rainfall |
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| Location |
May
|
June
|
July
|
Aug.
|
Sept.
|
| Freeport |
4.90 |
2.70
|
6.90
|
1.40
|
2.00
|
| Yorkville |
4.40
|
4.80
|
3.20
|
1.60
|
3.10
|
| Urbana |
6.29
|
2.78
|
2.73
|
7.27
|
1.77
|
| Perry |
9.15
|
4.60
|
4.75
|
4.46
|
0.85
|
| Belleville |
6.60
|
1.74
|
3.74
|
3.62
|
3.38
|
