Innovation in standard blowing procedures for Poa pratensis and ...

Oregon State University Seed Laboratory 

Innovations in Uniform Blowing Procedure using 

Orchardgrass and Kentucky bluegrass as a model 

Adriel.Garay@oscs.orst.edu

Goals of presentation: 

ti 

• Importance and history of UBP 

• Problems encountered with previous system 

• Critical elements of new system 

• AOSA acceptance of new system 

• Use and maintenance of new system

Importance 

• Rapid purity method for estimating the percentage of 

inert matter for certain grass species. 

• Uniformity is attained through the elimination of 

personal ljudgment tin classifying i florets into pure seed 

and inert components, and in reducing the variability of 

replicates for the germination test. 

• Theoretically, results within and among laboratories 

will be standardized if blowers are properly calibrated. 

D. Meyer CDFA/PPDC 2006

History 

• 1961 - UBP officially adopted for use on Kentucky 

bluegrass. 

• 1976 – UBP added for orchardgrass, Pensacola 

bahiagrass, rough and Canada bluegrass. 

• 1982 - UBP added for blue grama and side-oats grama. 

• 2003 – UBP added for weeping alkaligrass added. 

• 2006 – New blower calibration method accepted. 


Standard 

Calibration 

samples of 

Orchardgrass

General Blower

Purity Separation 

• Use the uniform blowing point established during the 

calibration to set the blower air gate opening. 

• Pure seed (heavy fraction) is separated from the inert matter 

(light fraction) by air flowing through the blower tube. 

Purity working sample 

of orchardgrass. 

After UBP, pure seed (heavy 

fraction) on left and inert matter 

(light fraction) on right. 


Problem !!! 

• The existing system did not provide 

checks and controls to verify uniformity 

across labs or within labs. 

• Some laboratories were using new 

calibration samples, while others were 

20+ years old. 


Calibration Samples do Deteriorate 

• Seeds decay over time. 

• Frequency of use contribute to physical 

changes of the florets. 

• Physical changes, or loosing critical sample 

components can have significant effects. 


Problem!!! 

All previous factors can cause: 

Variation in physical properties p of seeds (terminal 

velocity) 

Variation among calibration samples is expected and 

has been detected. 

Deviations among test results. 


Assessment of KBG cal. samples. 

• 12 Kentucky bluegrass calibration samples obtained from 

various labs in the USA. Test replicated in three general 

blowers. 


Assessment of OG cal. samples. 

12 orchardgrass calibration samples obtained from different 

labs within the USA. Test replicated in three general 

blowers. 


Conclusions about tOldS System 

• There was variation among calibration samples 

being used by laboratories 

• The system had no checks and controls to assure 

uniformity across labs and through time. 

• There was an urgent need to improve the system.

Proposed Solution !!!! 

• Establish and maintain a set of Uniform Calibration Samples 

“Master Calibration Samples (MCS)” 

. 

• All laboratories would be required to use the “MCS” to find 

the correct setting in their blowers. 

• Once a blower calibration is established, the equivalent air 

velocity (EAV) would be measured. 

• The blower would be set to the EAV for each standard 

blowing procedure. 

• AOSA-USDA would maintain the MCS. 


General Blower

Requirement of the New System 

• Each laboratory need to 

purchase an anemometer to 

measure air velocity to 

monitor blower calibration. 

• Cost of recommended 

anemometer is ca. $ 160. 


Anemometer 

indicating air 

velocity of 

2.3 m/s in 

General blower

Each Blower needs to be calibrated 

Air Velocity Profile of several General Blowers at the OSU Seedlab 

Blower ID 

Air opening in blower 4 5 7 

Equivalent air velocity (EAV) in m/s 

10.0 2.1 1.5 1.5 

10.5 2.2 1.7 1.7 

11.0 2.4 1.8 1.8 

11.5 2.5 2.0 2.0 

12.0 2.6 2.1 2.2 

12.5 2.8 2.3 2.3 

13.0 2.9 2.4 2.5 

13.5 3.1 2.6 2.7 

14.0 3.2 2.7 2.9 

14.5 3.4 2.9 3.1 

15.0 35 3.5 31 3.1 33 3.3 

15.5 3.7 3.2 3.5 

16.0 3.8 3.4 3.7

Validation of New System

Validation Across Blowers 

Using 10 Orchardgrass Samples 


Light iner rt blown (g) 

Separation of light-weight inert in 3 blind Orchardgrass samples 

when labs used their own calibration samples 

0.40 ( referee across 8 laboratories, 10 blowers) 

0.35 

030 0.30 

0.25 

0.20 

0.15 

0.10 

005 0.05 

0.00 

1 2 3 4 5 6 7 8 9 10 

Laboratories 

Low inert matter Medium inert matter High inert matter

0.40 

Separation of ligh-weight inert in 3 blind Orchardgrass samples 

when labs used uniform (master) calibration samples 

(referee across 8l laboratories, 10bl blowers) 

Light 

inert bl lown (g) 

0.35 

0.30 

0.25 

0.20 

0.15 

0.10 

0.05 

0.00 

1 2 3 4 5 6 7 8 9 10 

Laboratories 


wn (g ) 

g ht ine 

rt blo 

Li 

Comparison of blowing 3 OG samples in 10 laboratories based on 

air velocity when blowers calibrated with own lab's calibration 

samples and master calibration samples 

04 0.4 

0.3 

0.2 

0.1 

0 

1 2 3 4 5 6 7 8 9 10 

Laboratories 

Low Inert - Lab Own Cal 

Medium Inert - Lab Own Cal 

High Inert - Lab Own Cal 

Low Inert - Master Cal 

Med Inert - Master Cal 

High Inert - Master Cal

Validation of uniformity across 

blowers 

• Uniform separation of pure seed and inert matter of 5 Kentucky 

bluegrass samples with different levels of inert matter content 

across 7 blowers using the air velocity calibration method. 


separation of light-weight inert in 3 Kentucky bluegrass samples 

when labs used their own calibration samples 

(referee across 8 laboratories, 10 blowers) 

Lig ht inert b lo w n (g ) 

0.06 

0.05 

0.04 

0.03 

0.02 

001 0.01 

0 

1 2 3 4 5 6 7 8 9 10 

Laboratories 


Acceptance by AOSA 


Handbook 24 

THE UNIFORM BLOWING PROCEDURE 

Contribution No. 24 

To The Handbook On Seed Testing 

Provides detailed 

instructions on blowers, 

calibration samples, 

calibration procedures 

and dthe UBP. 

Published by the 

ASSOCIATION OF OFFICIAL SEED ANALYSTS 

1962 

Revised 

1978 

Revised 1983 

Revised 2004 

Revised 2006 


Blower Calibration 

The rule only applies to the 

General Blower. 



Master 

Calibration 

Sample 

Storage 

Pre-conditioning 



ato 

Light fraction 

Heavy fraction 

Set gate opening 

Entire sample 

in blower cup 

Blow sample 

exactly 3 min. 

Count the 

displaced seed 


Blower Calibration Review 

Blower Setting 

Trial number 

Light florets in 

heavy fraction 

Heavy florets in 

light fraction 

1 11 3 

12.00 2 13 5 

12.10 

3 15 3 

Average 13 4 

1 7 8 

2 7 5 

3 6 3 

Average 7 5 

1 4 13 

12.2020 

2 5 15 

3 1 9 

Average 3 12 



How to Measure Air Velocity 

• Establish optimum blowing 

point based on the “Master” 

calibration sample. 

• Set air gate opening at the 

optimum blowing point. 

• Remove the blower cup and 

center the anemometer fan 

over the opening at the base 

of the blower. 




• Turn anemometer on; set to measure 

meters/second. 

• Turn blower on and run for 30 – 60 seconds. 

• When digital read-out stabilizes record 

reading. 

• This air velocity is the “equivalent air velocity 

value.” 




When the UBP is used 

on the purity working 

sample the gate 

opening is adjusted to 

match the equivalent 

air velocity value 

established during the 

calibration for the kind 

of seed being tested. 

This setting will be 

blower specific! 


Species Without a Master 

Calibration Sample 

• Determine the optimum calibration point for Kentucky 

bluegrass as previous described. 

• The blower gate opening value for this point shall be 

multiplied by the appropriate factor for the kind of 

seed being tested. 

• Adjust blower gate opening to the new value. 

• Measure the equivalent air velocity value for the 

adjusted gate opening. 


Advantages of Using 

Master Calibration Samples 

• The Federal Lab administers i the MCS on loan to any 

AOSA-SCST Lab. This lab tracks the uniformity constantly. 

• Member Labs don’t need to purchase a calibration sample 

any more. 

• The system increases repeatability among laboratories that 

use the Master Calibration Samples. 

• It presents a model that can be used in other species. 


Advantages of using 

Equivalent Air Velocity 

The EAV is the causal factor of the desired seed separation. 

Once identified, the EAV is a fixed point in each individual blower 

The EAV changes only with change of glass tube or major repair. 

The use of EAV reduces the repeated use and deterioration of 

MCS ! 

Creates simplicity for daily monitoring of UBP!

Acknowledgements: 

Oregon Seed Council and Oregon Department of Agriculture 

for their financial support 

Northwest seed testing laboratories, AOSA and SCST for their 

suggestions and participation 

Laboratories that participated p in refereed research 

OSU Seed Laboratory staff for their constant research effort.

Innovation in standard blowing procedures for Poa pratensis and ...

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