An electronic instrument for the measurement and recording of leaf angles

Abstract Research in the last decades has shown the importance of the geometry of vegetation in defining the radiative regime within a crop canopy. Accordingly we have devised an electronic instrument to allow fast and accurate measurement of the angles of elevation, midrib azimuth and twist of leaves and branches. The measurement range of the instrument is 180° for elevation, 360° for azimuth and 120° for twist, with an accuracy of 2° and 1° for the last measurements, respectively. The accuracy of elevation measurements is 1° in the - 45°/+45° range and 3° in the remaining intervals. The stored data can be transferred to a personal computer using specially developed software that allows either the construction of numerical files in standard ASCII format or an initial processing into angular classes of variable width. The instrument is relatively inexpensive and provides acceptable accuracy and rapid execution, allowing the collection of the large data sets necessary for an exact description of the geometry of a crop.

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