Methodology and sampling technique of spray deposit and distribution measurement in vineyards

摘要

The investigation of spray deposits in vineyards is carried out to describe the application quality in terms of magnitude and variability of deposits with respect to sprayer function and sprayer adjustment. Very different sampling techniques are reported in published papers, making the comparison of data difficult or impossible. Differences are reported concerning the sampling unit, being artificial or natural. Sampling procedures reported are random samples or different systems of stratification. Investigations often just describe samples out of grape zone and upper leaf zone of the canopy but do not consider the vertical distribution profile. Deposit measurement is done by analysing individual units or bulk samples. Another aspect of confusion results from different understanding of the term "deposit" which is used for coverage on surfaces, number of particles/cm~2 or the initial deposit (ng/cm~2 or ng/g fresh weight). In this paper a sampling technique is proposed which enables to determine the magnitude and variation of deposits on upper and lower leaf side, berries and rachises as well as the spatial distribution in the leaf wall. These target units are supposed to be of epidemiological relevance in grapevines.