Team:
T. Berger (Bachelor Thesis) A. Schlagenhaufer (LfL)
Collaboration:
Prof. Dr. T. Ebertseder, Fakultät Nachhaltige Agrar- und Energiesysteme, (Faculty of Sustainable Agriculture and Energy Systems) Hochschule Weihenstephan-Triesdorf (HSWT)
Duration:
May 2021 to September 2021
Background and Objectives The European and Mediterranean Plant Protection Organization is calling for the introduction of a new plant protection model in hops as a function of the total leaf surface (the leaf wall). The question is whether or not the Leaf Wall Area model (LWA) or the Tree Row Volume model (TRV) are suitable as a replacement of the current model, which is based on the plant’s development stages. According to the new models and contrary to current practice, pesticides should no longer be applied in three stages but should be adapted to the foliage area of the crop. This would require the development of a uniform reference system that could be used for all plant cultures. This would also allow for regulatory approvals of plant protection products to become transferable among different crops and cultivation methods. To determine the suitability of the various models specifically for hop cultivation, part of the research of the bachelor thesis involved leaf area measurements, as well as plant height and width measurements. Method The experiments were set up with Perle and Herkules at two locations. At the start of vegetation, ten plants of each variety were planted, each with two shoots whose height and average width were measured weekly. For the height determinations, the length of each shoot was measured separately. In addition, the leaf areas of three bines of the two varieties were measured on three separate dates. This involved plucking all leaves on these bines by hand and sorting them according to size, with the aid of 10 templates. The templates allowed for the sorting of leaves into 10 categories. Figure 12 shows the template for category 8 as an example.
Figure 4.12: Template for categorizing leaf surfaces according to size
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