TEMPORAL VARIATION AND SPATIAL DISTRIBUTION OF RELATIVE INDICES OF LEAF CHLOROPHYLL IN GRAPEVINE cv. CHARDONNAY

Abstract

Variation in the spatial distribution of leaf chlorophyll content associated with the progression of the phenological cycle of crops may occur in cultivated areas as a result of the variability of environmental conditions and of the intrinsic properties of the plants. The objective of the present study was to model the trend in variation and assess the temporal stability of index of chlorophyll a, b, and total chlorophyll (Chla, Chlb, and Chlt, respectively), and to characterize the spatial distribution of Chlt index in grapevine cv. 'Chardonnay'. The assessments consisted of in situ measurements made with a portable meter in a commercial vineyard located in the municipality of Espírito Santo do Pinhal, state of São Paulo, Brazil, in the period between flowering and fruit maturation. Descriptive statistics were applied to the indices and regression models were fitted to ascertain the relationship of their mean variation with time. The temporal stability of Chlt index was estimated using Spearman's rank correlation analysis and thematic maps were created using geostatistical analysis and spatial estimation by ordinary kriging. The Chlb and Chlt indices were non-linearly associated with cycle progression and their decrease after the start of maturation was estimated. The temporal stability of the Chlt index was low and variation in its spatial distribution was observed over the assessed period.

Calibration of chlorophyll hand-held meter based on vineyard NDVI zones for estimation of leaf N content

“…However, Costa et al (2019) observed in the same Chardonnay vineyard that the chlorophyll content increased until the last evaluation at 120 dap in 2017 season, when maturation was completed. This divergent behavior can be explained by the climatic condition in which the vines evaluated by Costa et al (2019) were exposed, since it is a tropical climate with high solar incidence during almost the entire growing season.…”

“…Chl meters measure leaf absorbance at red and near-infrared wavelengths as chlorophylls strongly absorb the red light. The use of hand-held Chl meters makes possible to estimate both the leaf Chl and N contents through the fitting of models, providing a simple, low cost, fast and non-destructive field measurement, saving time and labor (Parry;Blonquist Jr;Bugbee, 2014;Kalaji et al, 2017;Brito et al, 2011;Rigon et al, 2013;Xiong et al, 2015;Costa et al, 2019;Walker et al, 2021).…”