Leaf volume index

Because parts of the model are used in the Dutch pesticide authorization procedure to estimate worker exposure during re-entry, a study was conducted to validate some of the aspects of the proposed model. Emphasis was put on the relationship between hie applied amount of active ingredient and the resulting increase of DFR in relevant zones (crop heights), as well as determining factors (i.e., application techniques and crop density, or leaf volume index). In addition, the influence of re-entry time and crop density on transfer factors (calculated from levels of re-entry exposure and either DFR or SFR) was studied. 

The results of the DFR assessment of different crop zones indicate that low-volume applications result in a more homogeneous distribution over the crop compared to high-volume applications. A recent study on the interception of high-volume applications in the cultivation of chrysanthemums revealed interception ratios from 0.2 to 1 related to the leaf area index (LAI) (Veerman et al., 1994). In our study, it was not easy to assess the LAI because of the structure of the carnation crop. Estimation of the LAI based on the results of estimation of the crop density (leaf volume index) was not reliable enough and resulted in a large variance of the calculated interception ratio (from 0.4 up to 5). 

Data sets are compilations of data, such as spectra or property tables. These data sets are often published serially as loose-leaf services, but the content is not always organized in chapters as in other serial publications. The citation of a serial data set should contain the title of the data set, the publisher, the place of publication, the date of the volume, the data entry number (as opposed to the data value), and the name of the figure or other identifying information. The page number can be included in the citation if page numbers are used in the index of the data set. 

Succulence reflects a tendency for reducing the surface of a plant relative to its volume (see Figs. 1.6, 1.10). If we assume a perfect sphere (perhaps the ideal succulent form) with a total volume of 1000 cm, the diameter would be 12.4 cm with a total surface area of 484 cm. A disc-like leaf of 1000 cm volume and 1 mm thick would have a total surface area over 20,000 cm. Hence, the disc shape will have a surface area some 41 times greater than the spherical shape of the same volume. Thermal consequences of the spherical shape for CAM plants will be discussed later (Chap. 5.3.6). The surface volume ratio of a plant or a plant organ, as well as its water-storing capacity, is quantitatively described by an index called Oberflachenentwicklung (i.e., surface expansion see Walter, 1926 Larcher, 1973)— where... 

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