Eine elektrische methode zur messung der blattbenetzungsdauer unmittelbar am blatt

✍ Scribed by Hans Häckel

• Publisher: Elsevier Science
• Year: 1974
• Weight: 990 KB
• Volume: 13
• Category: Article
• ISSN: 0002-1571
• DOI: 10.1016/0002-1571(74)90067-3

✦ Synopsis

H~ickel, H., 1974. Eine elektrische Methode zur Messung der Blattbenetzungsdauer unmittelbar am Blatt. (An electrical method for measuring the wetness duration immediately on leaves. ) Agric. Meteorol., 13: 91--103.

The instrument described in the following paper may be used for measuring the leafwetness duration immediately on the leaf. It consists of two pertinax frames. The first frame is stringed with bare wires of rare-metal. The second one is stringed with electrically isolated, green colored chicken wire. For the measurement the leaf is put between the two frames so that the chicken wire presses it against the wires of the raremetal. These wires are connected alternately with the two terminals of a high-frequency generator. If the leaf is wet, there will be an electric current; if the leaf is dry, there will be no current. A high frequency current has no ability for polarization, therefore no resistances will rise at the surface of the wires.

First tests have given a good correspondence between the measurements with this sensor and eye-observation. Results of comparisons with the hemp-threat wetness recorder by Woelfle are presented.