SOWACS: SEEDS as sensors - interesting!

[Marty Grogan]

Marty Grogan writes to the sowacs list:
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How about using some wire mesh on either side of the seed arranged to 
act a plates of a capacitor?  A capacitance bridge could be used for 
calibration and to monitor moisture.

M. G.

>Mark Bloomberg writes to the sowacs list:
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>
>My query relates to measuring moisture availability in the very small 
>space around a germinating pine seed.  This environment has a 
>diameter ca 1cm, is close to the soil surface and therefore moisture 
>levels fluctuate rapidly in relation to time of day, changes in 
>atmospheric RH etc.
>
>Oleskog & Sahlen (Oleskog,G and Sahlen K. 1999. Determination of 
>moisture conditions using Pinus sylvestris (L.)  seeds as biosensors.  
>Scandinavian journal of Forest Research.) stated that conventional 
>methods of soil moisture measurement are not suitable because they 
>may influence moisture levels in the seed's immediate environment, 
>which is very small.  There are also steep vertical gradients in 
>moisture in the  surface soil zone.  Oleskog opted for a bioassay 
>approach, using changes in seed fresh weight as an indicator of 
>moisture availability.
>
>Does anyone have alternative views on this problem?
>
>Yours sincerely, Mark
>
>Mark Bloomberg
>Lecturer in Forestry
>SPES Division, Lincoln University
>Ph (64) (3) 325 2811 Ext 8437
>
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